VIEWS: 204 PAGES: 87

									                                CENTRE FOR RENEWABLE
                                   ENERGY SOURCES

                                HYDROGEN PRODUCTION FROM

                                            Dr. N. Lymberopoulos

                            Project Technical Assistant Framework Contract
                             (EESD Contract No: NNE5-PTA-2002-003/1)

                                                    September 2005

19th Km Marathonos Ave., GR-190 09 Pikermi Attiki, Greece
Tel.: +30-210-6603300 Fax: +30-210-660
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                                     EESD Contract N°: NNE5-PTA-2002-003 / 1                                               PTA

                                                           TABLE OF CONTENTS

1.   INTRODUCTION ......................................................................................................................... 4
2.   THE HYDROGEN ENERGY VECTOR ...................................................................................... 5
  2.1.   Hydrogen properties............................................................................................................... 5
  2.2.   Hydrogen production, storage, use ........................................................................................ 6
  2.3.   Hydrogen in the research agenda ........................................................................................... 7
  2.4.   Hydrogen from renewables.................................................................................................... 8
3. ELECTROLYSIS BASICS ......................................................................................................... 11
  3.1.   Basic Principles of electrolysis ............................................................................................ 11
  3.2.   Alkaline electrolysis............................................................................................................. 13
  3.3.   Proton exchange membrane electrolysis.............................................................................. 14
  3.4.   Steam electrolysis ................................................................................................................ 15
  3.5.   Solid Oxide Electrolysis....................................................................................................... 16
4. REFORMING BASICS ............................................................................................................... 17
  4.1.   Steam reforming................................................................................................................... 17
  4.2.   Partial Oxidation .................................................................................................................. 17
  4.3.   Autothermal reforming ........................................................................................................ 18
5. BASICS OF OTHER RES-HYDROGEN PATHWAYS............................................................ 19
  5.1.   Hydrogen from biomass....................................................................................................... 19
  5.2.   Bio-processes for hydrogen production ............................................................................... 20
  5.3.   High temperature solar - Thermolysis ................................................................................. 21
  5.4.   Photo-electrochemical production ....................................................................................... 22
6. CASE STUDIES OF EXISTING RES-HYDROGEN INSTALLATIONS ................................ 24
  6.1.   Utsira.................................................................................................................................... 24
  6.2.   Stralsund .............................................................................................................................. 25
  6.3.   RES2H2 ............................................................................................................................... 27
  6.4.   FIRST project....................................................................................................................... 29
  6.5.   ENEA wind- hydrogen stand-alone system ......................................................................... 31
  6.6.   HYSOLAR........................................................................................................................... 33
  6.7.   SAPHYS .............................................................................................................................. 35
  6.8.   SWB project......................................................................................................................... 37
  6.9.   PHOEBUS ........................................................................................................................... 39
  6.10.    PURE project ................................................................................................................... 41
  6.11.    PVFSYS (Sophia Antipolis) ............................................................................................ 42
7. CURRENT R&D IN EUROPE .................................................................................................. 44
  7.1.   EC funded projects............................................................................................................... 45
  7.2.   National research efforts ...................................................................................................... 47
8. AREAS OF FURTHER RESEARCH ......................................................................................... 54
9. MARKET POTENTIAL OF RES-HYDROGEN SYSTEMS .................................................... 57
  9.1.   SWOT analysis of RES-Hydrogen stand alone systems (up to 300 kW) ............................ 57
  9.2.   Economic viability of RES-Hydrogen stand alone systems (up to 300 kW)....................... 58
  9.3.   Market Assessment of RES-Hydrogen stand alone systems (up to 300 kW)...................... 61
  9.4.   Market Assessment of wind-hydrogen systems (up to 5 MW)............................................ 64
  9.5.   Country-wide studies for wind-hydrogen technologies ....................................................... 65

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10.     CONCLUSIONS...................................................................................................................... 72
11.     REFERENCES......................................................................................................................... 73
12.     WEB SITES ............................................................................................................................. 77
13.     ANNEX I– MAJOR ELECTROLYSER MANUFACTURERS............................................. 78
  13.1.    AccaGen SA..................................................................................................................... 79
  13.2.    Casale Chemicals SA (& Metkon-Alyzer)....................................................................... 80
  13.3.    ErreDue ............................................................................................................................ 81
  13.4.    Gesellschaft für Hochleistungselektrolyseure zur Wasserstofferzeugung (GHW).......... 81
  13.5.    Giovanola Freres .............................................................................................................. 82
  13.6.    Hydrogenics ..................................................................................................................... 82
  13.7.    Linde ................................................................................................................................ 82
  13.8.    Norsk Hydro..................................................................................................................... 83
  13.9.    PIEL ................................................................................................................................. 83
  13.10.   Proton Energy Systems .................................................................................................... 84
  13.11.   Stuart Energy.................................................................................................................... 85
  13.12.   Teledyne Brown Engineering .......................................................................................... 85
14.     ANNEX II– MAJOR REFORMER MANUFACTURERS .................................................... 86
  14.1.    Johnson Matthey .............................................................................................................. 86
  14.2.    Argonne National Laboratory .......................................................................................... 86
  14.3.    Ceramic Fuel Cells........................................................................................................... 86
  14.4.    HELBIO SA..................................................................................................................... 86
  14.5.    HEXION .......................................................................................................................... 86
  14.6.    HONEYWELL................................................................................................................. 86
  14.7.    NUVERA ......................................................................................................................... 87
  14.8.    N-GHY............................................................................................................................. 87
  14.9.    Osaka Gas Co................................................................................................................... 87

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Hydrogen is heralded by many as the energy carrier of the future, the fuel that will replace
conventional liquid and gaseous fuels in stationary and transport applications. Hydrogen, although
abundant in nature, is always found in the form of compounds and high value energy needs to be
consumed for its production. The plethora of sources of hydrogen, like water or hydrocarbons, along
with the variety of methods to extract it from these compounds is the reason hydrogen is considered
the ultimate fuel, the introduction of which will lead to the establishment of energy “democracy”
around the globe: hydrogen can be produced in the most remote African village through a PV-
electrolyser system or in N. America using the heat from a nuclear reactor to thermally split water.

Hydrogen appears to have the potential to allow us to “overcome” the fact that fossil fuels are finite
and reduce the environmental impact from their combustion. However, the overall environmental
benefits accruing from the energetic use of hydrogen can only be realised if the complete hydrogen
production and use cycle is CO2 neutral. Hydrogen used as fuel, produced through the reforming of
hydrocarbons or through electrolysis that uses fossil fuel generated electricity involves CO2
emissions that in some cases could be higher than the conventional path of using fossil fuels directly.

It is the combination of hydrogen produced from renewables and Fuel Cells that holds the promise
for a sustainable future, in terms of resource availability and environmental protection. Fossil fuels
will be used in the short and medium term to help establish hydrogen infrastructures and
technologies, till the economics become right for renewables to take over. For electricity producing
renewables, it is most efficient to consume “instantly” the electricity produced for covering the
demand, if however there is an excess, then this could be stored in the form of hydrogen. Such niche
markets that would allow an increase of the penetration of renewables could be the Sherpas of the
hydrogen economy.

There are many paths that can be used to produce hydrogen from renewables, including electricity
producing renewables like wind, hydro, solar or geothermal energy, heat producing renewables, like
concentrated solar energy, methods to produce hydrogen from biomass or biofuels, processes that
mimic nature to produce hydrogen from wastes.

The present study covers the various pathways to produce hydrogen from renewables. A review is
initially given of the energetic properties of hydrogen, touching on the methods for its production,
storage and use. The international frameworks for the undertaking of research on the methods for the
production of hydrogen from renewable energy sources are then presented. The study moves on to
the basic principles governing electrolysis and reforming, which are the main production methods in
use today, however the principles of innovative techniques that are today in an early R&D phase are
also covered.

Various case studies of installations around Europe are then presented, covering mostly wind- and
solar-driven electrolysis plants. A review of current research efforts is presented followed by a listing
of areas requiring further research. The study concludes with a market assessment of energy systems
based on integrating renewables and hydrogen technologies. Non-exhaustive information on
electrolysis and reformer manufacturers is presented in annexes.

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Environmental concerns and security of supply issues support the transition from a fossil fuel based
society to a hydrogen society in order to meet our ever-increasing energy needs in a sustainable
manner. Historical trends prove that humanity, once in the industrial age, tends to use fuels whose
carbon content keeps on diminishing, with the hydrogen content increasing, rendering hydrogen as
the “ultimate” fuel. The combination of hydrogen, biofuels, electricity and fuel cells gives a promise
for a sustainable energy future for Europe and the world.

2.1. Hydrogen properties
Hydrogen is the most abundant element in nature but can be found only in compounds due to its high
reactivity (e.g. water, hydrocarbons), which on the other hand makes hydrogen such an interesting
fuel, suitable for many combustion applications (Table 1). Hydrogen can be produced from a variety
of energy sources and if “combusted” in fuel cells the only by-product is water vapour. However
hydrogen has its drawbacks: since it does not exist free in nature energy must be consumed to extract
it from its compounds. It has a high cost (twice the cost of gasoline per energy content) and is
difficult to store, specially in an energy-dense form. The following table compares the properties of
various energy carriers.

            Energy Carrier           H2        Methane          LPG         Methanol         Petrol        Lead
                                  (220 bar)     (NG)                                                      batteries
            Energy density    33.3                  12.9
                                                 13.9            5.6       12.7                             0.03
            per weight
            Energy density    0.53       2.6        7.5          4.4        8.7        0.09
            per volume
                    Table 1 Comparison of energy properties of various energy carriers

Hydrogen combusts in air in a much wider range than methane. Its explosion limits are also much
wider; it is these properties after all than render it such an interesting fuel. However, as can be
observed in the following table, hydrogen first goes through a combustion range, before going to the
explosion range (4-13% volume), meaning that it will most probably combust rather than explode,
which is not the case for methane (5-6%). Hydrogen being much lighter than air, disperses quickly
and much faster than methane.

                                                                       Hydrogen        Methane           Propane
            LCV (kWh/Nm3)                                                   3              9.9             25.9
            Density (kg/m3)                                               0.09             0.7               2
            Concentration for combustion (volume %)                    4.1 – 72.5      5.1 – 13.5        2.5 – 9.3
            Explosion limits (volume %)                                 13 – 65         6.3 – 14             -
            Dispersion coefficient (cm3/s)                                0.61            0.15               -
                 Table 2 Comparison of combustion properties of various energy carriers

    the weight of the storage tank for each fuel has not been taken into consideration with the exception of the lead batteries

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2.2. Hydrogen production, storage, use
Hydrogen can be produced from water through electrolysis or from fossil fuels through reforming.
The energy required by these processes can be obtained from various sources than include fossil
fuels, nuclear energy and renewable energy sources, including biofuels. This plurality in terms of
energy sources is one of the main advantages of the hydrogen energy vector, since the world
economy can disentangle itself from its dependency on oil. If hydrogen is produced through the
reforming of fossil fuels, then CO2 is released. Nuclear energy although CO2 free, has still to address
nuclear waste disposal issues. If hydrogen is produced through water electrolysis, then the emissions
related to its production are those associated with the power industry.

Vast quantities of hydrogen as an industrial gas are produced around the world. Total annual
production amounts to 500 billion normal cubic meters (Nm3/yr), equivalent to less than 10% of the
world oil production in 2002. Almost all of this hydrogen is produced from fossil fuels, as shown in
Table 3, while only 5% of this hydrogen is commercially used and distributed – the majority is
consumed internally in refineries or chemical plants. Commercial hydrogen sales are expected to
increase by over 8% per annum till 2008 [Trogish, 2004].

                                    Feedstock                   %
                                    Natural gas                 48
                                        Oil                     30
                                       Coal                     18
                                   Electrolysis                  4
           Table 3 Feedstock used in the global production of hydrogen [Trogisch, 2004]

Even though electrolysis provides a much more pure form of hydrogen, only a small percent of the
global production is obtained in this way in small plants due to the fact that it is much more costly
than natural gas reforming, which is three times more energy-efficient than electrolysis if fossil
source electricity is used (80% for reforming and 40% x 70%=28% for electricity production and
electrolysis). The following table shows indicative costs for hydrogen production.

                        Method                               Cost ($/GJ)
                        Natural Gas reforming                            5
                        Coal gasification                               11
                        Biomass gasification                            13
                        Electrolysis with large scale hydro             12
                        Wind electrolysis                               32
                        PV electrolysis                             50-100
                          Table 4 Hydrogen production costs [Hart, 1997]

The storage of hydrogen is considered as its “Achilles’ heal”. Its storage in an energy dense form is
particularly hard to achieve and is currently one of the many areas of research. Hydrogen is
commonly stored in gaseous form under pressure. Large storage tanks are under a pressure of 16 bar
while in cylinders hydrogen is stored under 200-250 bar. Pressures of 750bar are being
experimentally investigated for applications in the transport sector. Hydrogen in liquid form can be

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stored in special vacuum tanks, like the ones used in space applications. This type of storage
addresses the problem of storing hydrogen at high volume densities, however liquid hydrogen is still
four times less “energy dense” per volume as kerosene. Additionally, 40% of the energy contained in
gaseous hydrogen needs to be consumed for lowering the temperature of hydrogen down to 14
degrees Kelvin where it liquefies.

Innovative storage methods include bonding hydrogen in metal hydrides that are metal dusts whose
atom structure allows for the orderly packing of hydrogen atoms, thus achieving higher volume
densities than hydrogen in compressed gaseous form (volume is approx. that of gaseous hydrogen at
300 bar, for a tank pressure of 10 bar). The weight of these materials is however quite significant,
where usually only 1.5% of the total weight is the weight of hydrogen. Depending on the properties
of the metallic hydride dust, heat must be supplied to the tank for hydrogen to be released while heat
must be absorbed for charging the tanks with hydrogen.

The vast quantities of hydrogen produced today are consumed in non-energy related uses that are
summarised in the following table.

                                         Usage                 %
                              Ammonia production                 50
                              Refineries                         37
                              Methanol                            8
                              Space                               1
                              Other                               4
                               Table 5 Hydrogen usage [Hart, 1997]

Hydrogen is used in ammonia (NH3) production that in turn is used for the production of fertilisers.
In refineries hydrogen is used for the upgrading of fuels, mostly for the removal of sulphur.
Hydrogen is becoming the single most important product of the refinery so that the final products can
meet the ever more stringent fuel specifications, however it remains an internally consumed product
and rarely exits the refinery. The petrochemical industry uses hydrogen to produce methanol, which
as it will be seen later, is sometimes used in fuel cells where it is reformed to release its hydrogen
content. Hydrogen is also used in the food industry for the hydrogenation of fats. Some other uses
accrue from the physical properties of hydrogen, like lubrication, heat transfer (cooling of power
plant generators) or buoyancy (meteorological balloons).

The space programme of the USA has been the only case where hydrogen was used as a fuel.
Hydrogen can very well be burned in suitably modified boilers, gas turbines and internal combustion
engines. However, it is the development of fuel cells where hydrogen can be combusted with
minimal or no emissions that has opened new horizons for the energetic use of hydrogen in transport,
mobile, portable and stationary applications, spanning all types of human activities.

2.3. Hydrogen in the research agenda
Driven by recent technical advances in hydrogen and fuel cells technologies and the need for
diversified and sustainable technologies OECD governments are intensifying their R&D efforts.
Almost 1 billion Euro per year are invested globally for hydrogen and fuel cells research, the three

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main players being the US, Japan and Europe. Half of this amount is spent on fuel cells R&D and the
rest on technologies to produce, store and use hydrogen in other energy conversion devices like
internal combustion engines. The respective investment from the private sector is considerably larger
(approx. 3-4 billion Euro a year), including major oil and gas companies, car manufacturers,
electrical utilities, power plant component developers and a number of “small” players (SMEs) in the
current hydrogen and fuel cell market.

Multi-annual programmes have been announced by the major countries active in the field, including a
1.7 billion $ over 5 years in the US, 2 billion Euro in the 6th Framework Programme and the Growth
Initiative of the EC and 30 billion Yen per fiscal year in Japan. Similarly significant programmes are
in place in individual countries like Canada, Germany, Italy and others. These efforts are
complimented by three major international co-operation initiatives:

       The International Energy Agency (IEA) has formed in April 2003 the Hydrogen Co-
       ordination Group to enhance co-ordination among national R&D programmes, building on
       the IEA co-operation framework, including the Implementing Agreements on Hydrogen,
       Advanced fuel cells and others
       In November 2003, sixteen countries including non-OECD countries Russia, Brazil, India and
       China have formed the International Partnership for the Hydrogen Economy (IPHE),
       following a proposal of the US
       In January 2004, the EC established the European Hydrogen and Fuel cells technology
       platform (HFP), which is a cluster of public and private initiatives aiming to co-ordinate and
       promote the development and application of hydrogen energy technologies including fuel

A review of the national R&D programmes on hydrogen and fuel cells has recently been published
by the IEA, in the context of the previously mentioned Hydrogen Co-ordination Group work, in
which the current author was a contributing member covering Greece [IEA, 2004].

2.4. Hydrogen from renewables
Long-term forecasts for hydrogen production show some deficiencies between supply and demand,
implying that increased production must be covered from alternative energy sources, including
renewables. One should not forget that the production of hydrogen from fossil fuels results to CO2
emissions, the quantities of which per mole of hydrogen produced depend on the feedstock and
production technology used. Natural gas is the fossil fuel with the highest hydrogen to carbon ratio,
however hydrogen from electricity producing renewables or from CO2-neutral biomass are the ways
for producing hydrogen in a distributed fashion without any CO2 emissions.

Hydrogen production from nuclear energy is also CO2-free, however the handling of nuclear wastes
is not yet solved while uranium is found in fewer places in the world than oil, meaning that the
dependency on few countries possessing raw materials with remain. Also the technologies used are
very complicated and only a few countries and companies posses the knowledge for the development
of nuclear plants. Hydrogen from renewables has none of these problems since renewables are
indigenous and available around the globe, while RES technologies and hydrogen production and use
technologies can be manufactured almost anywhere around the globe.

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Hydrogen from fossil fuels can also be CO2 free if CO2 sequestration is to be applied. The method
has been demonstrated in the North Sea where CO2 is pumped back into oil wells to enhance the
extraction of oil. However this approach would greatly increase the cost of hydrogen and would
create a problem of what to do with the large quantities of the produced CO2.

It is thus predicted that even if fossil and nuclear fuels can be sources of hydrogen in the short to
medium term, it is renewables that will be the sources of hydrogen in the long-term. The hydrogen
vision compiled by the European Commission High Level Group on Hydrogen and Fuel Cells
Technologies demonstrates this trend (blue arrows indicate role of RES in the Hydrogen economy).

                                                         A CHALLENGING EUROPEAN HYDROGEN VISION
                                                                                               direct H2 production from renewables;
                                                                                               de-carbonised H2 society
                                                                                                                                                   s n
                             n                     Increasing de-carbonisation of H2 production;                                                fit atio
                          io                                                                                                                 n e i al i z
                        ct ion
                                                   renewables, fossil fuel with sequestration, new nuclear       2040                      be erc ns ns
                      u                                                                                                           e
                                                                                                                                at m tio tio
                    od ut                                                                                                     iv com ica lica
                  pr trib                                                                                               d c
                                                                                                                            pr ale appl app
                H2 dis
                                                                                                                                                                     n               H2 use in aviation;
                                                                                                                   an e-s bile ary                               t io
                                                                                                                 rd l larg mo ation                            ra
                  &                                                                             2030            a e l C st                                et
                                           Widespread H2 pipeline infrastructure                              w         F                               en
                                                                                                            re el C         FC                     tp
                                                                                                         lic Fu                                  ke                        Fuel cells become dominant
                                                                                                        b d                                    ar          2040
                        Interconnection of local H2 distribution grids;                               Pu an ion
                                                                                                          n ct t                       g
                                                                                                                                           m                               technology in transport, in
                        significant H2 production from renewables, incl.                                ge u or                    si n                                    distributed power generation,
                                                                                                      ro rod sp               ea
                        Biomass gasification                                 2020                   yd 2P ran ge
                                                                                                   H H T ra            In
                                                                                                                         cr                                                and in micro-applications
       H2 produced from fossil fuels with C sequestration                                                H 2 St
                                                                                           n               H2
              Clusters of local H2 distribution grids;                            rt trat                               2030
                                                                             e ffo ons tion)                                             H2 prime fuel choice for FC vehicles
                                                                            e m ra     e
          Local clusters of H2 filling stations
                                                                             at h, D ene                                         Significant growth in distributed power generation
     H2 transport by road, and local H2
                                               2010                       iv            g                                        with substantial penetration of FCs
                                                                    pr a r c a l ,
     production at refuelling station (reforming                  d ese ctric ation                                         2nd generation on-board storage (long-range)
     and electrolysis)                                         an d r ele ort                               2020 Low-cost high temperature fuel cell systems;
                                                             e ie                p
 H2 produced by reforming natural gas                     tiv ppl and ans                       ts
 and electrolysis                                     c en h, A les n, tr                  flee                       FCs commercial in micro-applications
                                                   in rc ic tio                          e                     FC vehicles competitive for passenger cars
                                                i c esea (veh duc se                 ich                    SOFC   systems atmospheric and hybrid commercial (<10MW)
                                              bl l r lls ro d u                st
                                          Pu enta l Ce en p an              te                           First H2 fleets (1st generation H2 storage)
                                                   e g        n          ld
                                            am Fu dro utio            ie            2010 Series production of(boats); FC for auxiliary(direct H2 and on-board reforming)
                                                                                                                         FC vehicles for fleets
                       2000              nd        Hy strib        ,f
                                                                                                   and other transport                           power units(incl. reformer)
                                                     di       R TD
                                                                                           Stationary low temperature fuel cell systems (PEM) (<300kW)
                                                                                                                                                                              s te t
                 Fossil fuel-based                                              Stationary high-temperature fuel cells systems (MCFC/SOFC) (<500kW);                       sy n
                                                                                H2 ICEdeveloped; Demonstration fleets of FC-buses
                                                                                                                                                                     d  H2 pme ent
                     economy                                       Stationary low temperature fuel cell systems for                                               an lo m
                                                   2000            niche commercial (<50kW)                                                                     C eve loy   F     D dep

                                     Fig. 1 Role of Renewables in the Hydrogen economy
                                 [High Level Group of Hydrogen and Fuel Cells Technologies]

One should keep in perspective though that other energy outlook studies of the European
Commission, like the WETO study [WETO, 2003], do not foresee that hydrogen is to play a major
role in the energy scene till 2030, indicating that perhaps the predicted road map is slightly optimistic
for hydrogen.

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On the more technological aspects of producing hydrogen, the various pathways are depicted
schematically in figure 2 below:

                        Fig. 2 Hydrogen production pathways [Turner, 1999]

The various possible pathways for producing hydrogen from renewable energy sources are
summarised below:
   • hydrogen from renewable electricity sources (wind, solar, geothermal, hydro, wave, biomass1)
      through electrolysis
   • hydrogen through reforming of biomass-derived fuels1
   • hydrogen through gasification or pyrolysis of biomass1
   • biological and bio-mimetic hydrogen production (bio-photolysis and fermentation)
   • high temperature solar thermochemical production - thermolysis
   • photo-electrochemical production – photo-electrolysis

Electrolysis, gasification and reforming - particularly large scale reforming of fossil fuels - are well
established technologies while the other pathways are still in an early development phase,
characterised by low efficiencies but also great potential for improvement. The basic principles
governing these pathways are described in more detail in the following chapters.

 The efficiency of the various pathways for producing hydrogen from biomass varies. The optimum
path would depend on local conditions

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3.1. Basic Principles of electrolysis
Electrolysis is an electrochemical process in which electrical energy is the driving force of chemical
reactions. Substances are decomposed, by passing a current through them. The first observation of
this phenomenon was recorded in 1789. Nicholson and Carlisle were the first who developed this
technique back in 1800 and by the beginning of the 20th century there were already 400 industrial
water electrolysis units in use.

In figure 3 a schematic of an electrochemical cell is presented. The core of an electrolysis unit is an
electrochemical cell, which is filled with pure water and has two electrodes connected with an
external power supply. At a certain voltage, which is called critical voltage, between both electrodes,
the electrodes start to produce hydrogen gas at the negatively biased electrode and oxygen gas at the
positively biased electrode. The amount of gases produced per unit time is directly related to the
current that passes through the electrochemical cell. In water, there is always a certain percentage
found as ionic species; H+ and OH- represented by the equilibrium equation:

                                  Fig.3. Sketch of an electrochemical cell [Neagu, 2000].

       H2O (l)↔ H+ (aq) + OH- (aq)

Oxygen and hydrogen gas can be generated at noble metal electrodes by the electrolysis of water:

       +VE electrode (anode):                  4OH- ↔ 2H2O + O2 + 4e-

       -VE electrode (cathode):                2H+ (aq) + 2e- ↔ H2 (g)

The reactions occurring at the electrode interface are slightly different, for the cases of acidic or basic
water. In water electrolysis there are no side reactions that could yield undesired byproducts,
therefore the net balance is:

       2H2O → (4e-) → O2 + 2H2
The minimum necessary cell voltage for the start-up of electrolysis,             E   cell   , is given under standard
conditions (P, T constant) by the following equation:
                       − ∆G

        E   cell

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where ∆Go is the change in the Gibbs free energy under standard conditions and n is the number of
electrons transferred. In the case of a closed electrochemical cell, the conditions slightly change from
standard conditions, open cell (P, T) = constant to closed cell (V, T) = constant because the change in
the cell volume is smaller compared to that of pressure. Therefore, instead of ∆Go, ∆Ao – free energy
(Helmholtz) is used.

The necessary voltage for an electron to overcome the Helmholtz energy barrier is given below:
                       − ∆A

        E   cell

       ∆Αο = ∆Ηο – ΤR∆n - T∆So

For the electrolysis of water, the standard reaction enthalpy is, ∆Ηο = 285.8 (kJ/mol), ∆n = 1.5,
∆So(H2) = 130.6, ∆So(O2) = 205.1, ∆So(H2O) (l) = 70 J/mol K, ∆Sotot = 130.6 + ½ 205.1 – 70 =
163.14 J/mol K, and ∆Αο = 233.1 (kJ/mol). So, the minimum necessary cell voltage is Ecell = 1.21 V.
In the case of an open cell, Eocell = -∆Go/ ηF = 1.23 V, with ∆Go = ∆Ηο – Τ∆So = 237.2 kJ/mol
(standard conditions, 1 bar, 25 oC).

In order for a reaction to get started, it is necessary to overcome an additional energy barrier, namely
the activation energy Eact. The number of molecules able to overcome this barrier is the controlling
agent of the reacton rate, r, and it is given by the statistical Maxwell – Boltzman relation which has
an exponential behaviour: r ~ro exp(-Eact/RT). So, the activation energy expresses the speed with
which a reaction takes place.

The maximum possible efficiency of an ideal closed electrochemical cell is defined by the following

                       ∆Η     ∆Η
       εmax =             =-
                       ∆Α    ηFE cell

In practice, the efficiency of an electrochemical cell is given by:

       εreal = -
                       ηΕ elec

where ∆Eelec is the voltage to drive the electrochemical cell at I:

       ∆Eelec = ∆Α + IR + Ση

Where R is the total ohmic series resistance in the cell including external circuit resistance,
electrolyte, electrodes, membrane material; Ση is the sum of the overpotentials (activation
overpotential at the two electrodes, and the concentration overpotential due to the mass transport of

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the gaseous products away from the anode and cathode surfaces). The balance energy, per mole,
during water electrolysis is shown in Fig.4. The activation overpotential increases by increasing the
current density and can be lowered by using electrodes which have a catalytic action, such as

                         Fig.4. Energies involved in a reaction [Neagu, 2000].

For water electrolysis, under ideal reversible conditions, the maximum theoretical efficiency with
respect to the electrical energy source would be εmax = 120%. Therefore, heat would have to flow into
the cell from the surroundings. When the value of the denominator in Eq.7 becomes 1.48 ηF
(overpotential of 0.25V), the electrochemical cell would perform at 100% efficiency. Under these
conditions (∆S = 0, Ση = 0, so ∆G = ∆Η), the cell does not heat or cool and the value of Εtn = ∆Η /
ηF = 1.48 V is denoted as the thermoneutral potential. The electrochemical cell produces heat at
potentials above 1.48 V and takes heat in at potentials below this value, under the condition that cell
temperature is to be maintained constant. In practice, the IR drop may be ca 0.25V. The overpotential
η should be kept low so as to maximize the efficiency and to minimize the production of heat. On the
other hand, the lower the overpotential the slower the reaction will occur, so we have to make a
compromise. One of the best ways to increase the current without increasing the overpotential is to
increase the contact areas between the electrodes and the liquid [Neagu, 2000].

Electrolysis plants with normal or slightly elevated pressure usually operate at electrolyte
temperature of 70-90oC, cell voltage of 1.85-2.05 V and consume 4-5 KWh / m3 of hydrogen, which
is obtained at a purity of 99.8% and more. Pressure electrolysis units run at 6-200 bar and there is no
significant influence on the power consumption. Because of its high energy consumption and also of
the quite substantial investment, water electrolysis is currently used for only 4% of world hydrogen
production. [Varkaraki, 2003]

3.2. Alkaline electrolysis
In the initial discovery of electrolysis, an acidic water solution was used, but nowadays there exist
only alkaline electrolytes such as potassium hydroxide (KOH). This technology offers the advantages
of materials which are cheaper and less susceptible to corrosion compared to those required to handle
acids. The first large scale plant was operated in 1948, while a pressurised and more efficient type
was constructed in 1948. In order to build a large-scale electrolysis plant, each small electrolysis cell
is linked to another in series (bipolar) or parallel (unipolar) arrangements to produce a sufficient
amount of current and thus hydrogen product [Hart, 1997].

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The principle of alkaline water electrolysis is schematically shown in Fig.3 (monopolar tank
electrolyser). Two molecules of water are reduced to one molecule of hydrogen and two hydroxyl
ions at the cathode. The hydrogen escapes from the surface of the cathode recombined in a gaseous
form and the hydroxyl ions migrate under the influence of the electrical field between cathode and
anode through the porous diaphragm to the anode, where they are discharged to ½ molecule of
oxygen and one molecule of water.

                       Fig.5. Principle of alkaline electrolysis [Kreuter, 1998].

Oxygen and hydrogen recombine at the electrode surface and escape as gases. Whereas atmospheric
pressure electrolysers are mainly built in monopolar tanks, which is the simplest construction
principle, pressurized electrolysers are manufactured in the so-called bipolar filter press arrangement.
The main reasons for the bipolar arrangement are the savings in space and in electrical bus bars and
housing material, which are essential for large pressurized plants. A small disadvantage of the bipolar
type when compared to the monopolar, is the occurrence of shunt currents inside the electrolyte ducts
of the bipolar electrolyser. This can be addressed through a more sophisticated design of the
electrolyte and gas ducts and the application of a small protection current during operational shut-
down times.

3.3. Proton exchange membrane electrolysis
The proton exchange membrane water electrolysis is based on the use of a polymeric proton
exchange membrane as the solid electrolyte (‘polymer electrolyte membrane’) and was first proposed
by General Electric for fuel cell, and later, electrolyser applications. The proton exchange membrane
electrolyser technology was developed in the 70s and 80s by ABB, Switzerland.

The inherent advantages of polymer electrolyte technology over the alkaline one are:

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   (i)     greater safety and reliability are expected since no caustic electrolyte is circulated in the
           cell stack
   (ii)    previous tests made on bare membranes demonstrated that some materials could sustain
           high differential pressure without damage and were efficient in preventing gas mixing
   (iii)   the possibility of operating cells up to several amps per square centimeter with typical
           thickness of a few millimeters [Millet, 1996].

Ultrapure water (1 µSiemens compared to 5 µSiemens for an alkaline unit) is fed to the anode
structure of the electrolysis cell which is made of porous titanium and activated by a mixed noble
metal oxide catalyst. The membrane conducts hydrated protons from the anode to the cathode side.
Appropriate swelling procedures have led to low ohmic resistances enabling high current density of
the cells. The standard membrane material used in PEM water electrolysis units and PEM fuel cells is
NafionTM 117, manufactured by DuPont. The cathode of such an electrolyser consists of a porous
graphite current collector with either Pt or, in more recent designs, a mixed oxide as electrocatalyst.
Individual cells are stacked into bipolar modules with graphite based separator plates providing the
manifolds for water feed and gas evacuation. The operation of the cells leads to electro-osmotic water
transport through the membrane from the anode to the cathode side.

The technology has been demonstrated on a 100 kW commercial scale in two units: Stellram/ATEL
(1987-1990 and 1991-present) unit and SWB, Solar-Wasserstoff-Bayern GmbH (1990-1996) unit
(chapter 6.8). The operation of these two electrolysers has successfully demonstrated the feasibility
of this technology for industrial hydrogen production. A major problem of electrolysers of this type is
the limited lifetime of the electrolysis cells.

The first commercial scale PEM electrolyser was installed in 1987 at Stellram SA, a metallurgical
specialty company, in Nyon, Switzerland. The unit was designed to produce up to 20 Nm3/h of
hydrogen at a pressure of 1-2 bar. The plant consisted of 120 cells of 20 x 20 cm2 active area each,
grouped into four modules of 30 cells, and electrically connected in series. The nominal operating
conditions for the plant at start-up were 400 A (i.e. 10 kA/m2), at 80 oC. Cell voltages at these
operating conditions were typically of the order of 1.75 V. The plant was operated at variable load,
according to the hydrogen needs of the metallurgical process, for approximately 15000 hours before
it had to be shut down in 1990. By this time the voltage across a number of cells had drastically
dropped, indicating short circuits within these cells as the reason for gas leakages and gas purity

Today PEM electrolysers are developed commercially (chapter 14.10) in the range 0.5 to 10
Nm3H2/hr, producing hydrogen of very high purity, at prices comparable to that of alkaline units.
Versions of such electrolysers suitable for coupling with stochastic renewable energy sources are
available but currently have limited warranty.

3.4. Steam electrolysis
Steam electrolysis is a technology that has the potential to reach higher total energy efficiency
compared to alkaline and proton exchange membrane electrolysis. From the thermodynamic
viewpoint of water decomposition, it is more advantageous to electrolyse water at high temperature
(800-1000 oC) because the energy is supplied in mixed form of electricity and heat. The main

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advantage is that a substantial part of the energy needed for the electrolysis process is added as heat,
which is much cheaper than electrical energy. In addition, the high temperature accelerates the
reaction kinetics, reducing the energy loss due to electrode polarization, thus increasing the overall
system efficiency. A typical high temperature electrolyser such as the German HOT ELLY system
achieves an electrical efficiency of 92% while low temperature electrolysers can reach 85%
efficiency at most (cell stack efficiency).

The high temperature system employs oxygen ion conducting ceramics as the electrolyte. The fluid to
be dissociated is 200 oC steam which, after being further heated to 800-1000 oC, enters at the cathode
side. After the steam is split to hydrogen gas and O-- ions, the oxygen ions are transported through the
ceramic material to the anode, where they discharge and form oxygen gas. Despite this high
efficiency with respect to electricity, the high temperature system still produces hydrogen at about
four times the cost of hydrogen produced through steam reforming of natural gas.

A new approach to reduce the electricity consumption in electrolysers was achieved by using natural
gas in order to reduce the chemical potential difference across the electrolyser cell. The concept is
called Natural-Gas-Assisted-Steam Electrolysis (NGASE). In this new technology, the air in the
anode side is replaced with natural gas in order to lower the open circuit voltage and thereby the
electricity consumption. The reducing character of natural gas helps to lower the chemical potential
difference between the two sides of the electrolyser. The scale-up to large water electrolysis units
using this technology is currently under development.

3.5. Solid Oxide Electrolysis
This could be a sub-category of steam electrolysis. The operation of a solid-oxide electrolyser
depends on a solid ceramic electrolyte (zirconia/ceria), which at temperatures of 800-1000oC
transfers oxygen ions (O2-). The solid oxide electrolyser requires a source of high-temperature heat.
By operating at elevated temperatures, the heat input meets some of the energetic requirement for
electrolysis and so less electricity is required per m3 of H2 generated, compared with the other
electrolyser technologies. To date, prototype solid-oxide electrolyser units have not achieved useful
operational lives and substantial engineering problems exist with respect to thermal cycling and gas
sealing. Accordingly, it is premature to make comparisons with alkaline and PEM electrolysers
[Newborough, 2004].

The previously mentioned steam electrolysis and solid oxide electrolysis are both suitable for
operation along a high temperature nuclear plant, that would provide the electricity and high –
temperature heat aiming for the case of large scale centralised production of hydrogen. For smaller
distributed generation applications, heat could be supplied by a solar concentrator and electricity by
wind turbines or photovoltaics.

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Reforming is the generic term used for converting hydrocarbons into hydrogen and CO2. There are
three basic reforming techniques, steam reforming (endothermic), partial-oxidation (exothermic) and
autothermal reforming (combination of the previous two; close to thermal equilibrium). The
reforming process consumes between 20-30 % of the energy contained in the fuel to be reformed.
Besides hydrocarbons, reforming can be applied to biomass derived fuels for the rpoduction of

4.1. Steam reforming
Steam reforming (SR) is currently the most wide spread method for producing hydrogen from light
hydrocarbons thanks to the relative simplicity of the method. Fuel is mixed with superheated steam at
1,100oC under pressure and in the presence of a nickel based catalyst. Carbon in the fuel is oxidised
producing carbon monoxide while hydrogen is released:

                                CnHm + nH2O → nCO + (n + m/2) H2

The CO is then subjected to a further reaction at 400 – 500 oC, known as water gas shift reaction in
which it is reacted with water to produce more hydrogen and CO2.

                                       CO + H2O → CO2 + H2

The temperature regime of the reactions and the catalyst used depends on the fuel to be reformed. If
for example methanol is the feedstock, then this process takes place at 300 oC, making the process
suitable even for transport applications. The range of feedstocks is limited to final boiling point and
aromatic content. Methane (as in natural gas or biogas) can be reformed as well as propane and
butane, but higher hydrocarbons need to go through a pre-reforming process producing hydrogen,
methane and carbon oxides.

Steam reforming is most efficient at large scales but less effective at a scale as that suitable for use
inside a car, where the energy spent would be almost 40%. At the same time steam reformers are
rather bulky and since high temperatures are required, they are slow to respond to start-ups or
transients in general.

4.2. Partial Oxidation
As the name implies, partial oxidation or POX is the partial or incomplete combustion of a fuel,
resulting from the use of a substoichiometric amount of oxygen (air). The process is highly
exothermic and self sustaining, however for small-scale applications a catalyst could be used to
increase reaction rates are lower reaction temperatures. The process is mostly used for liquid fuels.

During partial oxidation the incomplete burning of hydrocarbons produces char, vapours and oils.
These are quenched through the introduction of superheated steam which promotes the water-gas
shift reaction (described previously under steam reforming) necessary to reduce CO and increase H2

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For the case of methane:

                                     CH4 + ½O2 ↔ CO + 2 H2

While for pentane:

                                   C5H12 + 5/2O2 ↔ 5CO + 6H2

Non catalytic POX reactions can require temperatures as high as 1,000oC for the case of petrol,
which implies the use of special materials. The reduction of temperatures through nickel-based
catalysts means that standard materials can be used and that the amounts of CO are reduced, meaning
a smaller shift reactor is required. Overall efficiency is also improved.

For heavier hydrocarbons, reaction temperatures can range from 870oC for catalytic POX up to
1,400oC for non-catalytic POX. For diesel fuel with high sulphur concentrations, reaction
temperatures are 925oC for catalytic POX and 1,175oC for non-catalytic POX.

Usually POX reactors have better efficiencies than steam reformers and are more compact since no
external heat transfer is required, thus more suitable for transport applications. However the high
temperatures involved result to low H2 and CO2 selectivity and construction materials constraints,
while in the case of steam reforming, the H2 and CO2 selectivity is higher. Designers choose among
the two processes depending on the particular application.

4.3. Autothermal reforming
The autothermal reformer or ATR is a hybrid between the steam reformer and the partial oxidiser. In
such a reactor heat is internally exchanged between the endothermic steam reforming reaction and
the exothermic partial oxidation reaction. A catalyst is required to determine the relative extents of
each reaction. Maximum temperatures are limited by the fact that the SR reaction absorbs heat from
the POX reaction. Autothermal reforming provides a fuel processor compromise that operates at a
lower temperature than the POX, is smaller, quicker starting, and quicker responding than the SR and
results in good H2 concentration and high efficiency that is equal or better than that of a steam

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5.1. Hydrogen from biomass
Gasification technology has been under intensive development over the last two decades and large-
scale demonstration facilities have been tested and many commercial units are in operation, the
quality of the gas produced however – in terms of hydrogen purity – is low. Until recently, biomass
gasification has been employed to produce electricity or heat, which rarely justify the capital and
operating costs. No commercial plants exist today to produce hydrogen from biomass, however the
increasing demand for hydrogen promises to drive research and development of biomass gasification
projects in the near future.

Currently, the pathways followed are steam gasification (direct or indirect), entrained flow
gasification, and more advanced concepts such as gasification in supercritical water, application of
thermo-chemical cycles, or the conversion of intermediates (e.g. ethanol, bio-oil or torrified wood).
None of the concepts have reached a demonstration phase for hydrogen production. Biomass
gasification is an R&D area shared between H2 production and biofuels production. Gasification (and
pyrolysis) is considered the most promising medium term technology for commercialisation of H2-
production from biomass.

A number of countries have allocated R&D resources towards the production of hydrogen from
biomass sources. Austria, which has been a leader in developing biofuels for transportation, has two
demonstration plants and several pilot projects dedicated to gasification, conversion and purification
of biomass for hydrogen production. Belgium is investigating the production of hydrogen for fuel cell
from organic residues, and the GAZOPILE program focuses on fuel cell feeding from wood gas
generation. In Norway, a bio-hydrogen project has the objective to identify a process to gasify
biomass and generate hydrogen with a purity sufficient for use with SOFCs. Spain has several R&D
projects for producing hydrogen from waste biomass sources, including the development of
bioethanol-to-hydrogen conversion facility using fermentation processes. A €62,000 project in
Greece is designed to test catalysts and reactors for reformation of ethanol and biogas for hydrogen.
The Greek Company, Helbio, is planning to commercialize an ethanol fuel processor system for
hydrogen production from biomass for remote, off-grid locations and areas of inexpensive ethanol
production such as Brazil, China and India. The Netherlands has a number of hydrogen from biomass
projects under its Biohydrogen Platform, which is a collaborative effort among eleven Dutch
institutes and universities concentrating on pyrolysis and supercritical water gasification.

In the US, the plan for 2010 is to develop and demonstrate technology to supply purified hydrogen
(purity sufficient for polymer electrolyte membrane (PEM) fuel cells) from biomass at $2.60/kg at
the plant gate (projected to a commercial scale 75,000 kg/day). The objective is to be competitive
with gasoline by 2015. There is also a “Hydrogen Production from Biomass (pyrolysis, gasification,
and fermentation) program” funded at US$4 million. The EU sponsored “CHRISGAS” consortium
aims to develop a large scale biomass gasification process to produce a clean gas rich in hydrogen
which can be used for the production of vehicle fuel. This program will be funded with €9.5 million.

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5.2. Bio-processes for hydrogen production
Bioprocesses for hydrogen production are in an early stage of development. Processes are usually
split in those requiring incident sunlight (bio-photolysis and photo-fermentation) and those that can
be carried out in the absence of light (dark fermentations) [WIBA, 2005]

The starting process of bio-photolysis is photosynthesis, in which water is split into oxygen, protons
and electrons (water splitting) with the aid of sunlight. Normally, the electrons set free in this process
are then used for building up biomass together with atmospheric carbon dioxide. However, certain
green algae and cyanobacteria are also capable of transferring the electrons to protons thus forming
molecular hydrogen. The great advantage of this process is that only water is needed as the starting
material. In principle this is an attractive H2 pathway, because of the simple process inputs and
because photosynthetic micro-organisms are capable of highly efficient use of sunlight, several times
higher than the efficiency associated with photosynthetic biomass production.

In photo-fermentation hydrogen is produced by anaerobic photosynthetic bacteria employing
nitrogenase instead of hydrogenase to transfer reducing power from organic substrates, preferably
organic acids. Although more metabolic energy is required in the case of nitrogenase, this enzyme is
not inhibited by hydrogen. This is a great advantage that can be exploited to enable high conversion
rates e.g. using high-density systems.

Major breakthroughs are required before bioprocesses can meaningfully contribute to ‘sustainable
hydrogen’ production. These breakthroughs are needed both in relation to biological conversion
efficiencies and yields, for which advances in biology and genetic engineering should provide input,
but also in relation to reactor technology, specifically the design and construction of cheap, large
bioreactors. A major challenge for these photobiological processes is thus to achieve high light
conversion efficiency combined with a high hydrogen production rate. This is essential in order to
reduce land requirement and costs of photobioreactor systems. Reasonable light conversion
efficiencies have thus far only been obtained at low light intensities with associated low hydrogen
production rates. In more realistic, higher light intensities the efficiency is thus far restricted to below
1%, where 10% would be the typical minimum requirement for these methods to be considered as
economically viable H2 production routes.

                 Fig. 6 Experimental investigation of bioreactor designs [Riis, 2004]

In dark fermentations hydrogen along with organic acids and CO2 are produced in the absence of
sunlight from organic substrates, in particular wet biomass, under anaerobic conditions by bacteria
employing hydrogenases. In current R&D there is considerable attention for extreme thermophilic
fermentations at temperatures above 70 °C, giving much higher hydrogen yields than ambient-

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temperature fermentations. A present drawback here is the incomplete oxidation of the organic
substrate to organic acids. [SRA, 2005]

          Fig. 7 Experimental fermentative conversion of biomass to hydrogen [Riis, 2004]

Many small-scale projects have successfully demonstrated the ability of these technologies to
produce hydrogen albeit at the very low efficiencies previously quoted and very high costs.
Nonetheless, the body of knowledge in this area of research is increasing rapidly. Key areas for on-
going fundamental R&D efforts related to bio-processes for hydrogen production include:
   • Studies of genetic mechanisms and biochemical pathways of hydrogen metabolism.
   • Hydrogen metabolism investigations of micro-algae in daylight and darkness.
   • Maximization of photosynthetic efficiencies.
   • Improvement of oxygen tolerance of algae.
   • Hydrogen fermentation processes.
   • Recycling of algal cells after hydrogen evolution process.
   • Development of bioreactor systems that operate under visible light
   • Future ocean-based systems are envisaged, with low tech designs using salt water, integrated
       into an overall bio-refinery concept

Photo-biological work has been undertaken in Austria, focusing on anaerobic digestion of different
substrates and purification systems. French research agencies CEA and CNRS conduct research in
photo-biological processes in cooperation with other European programs, in particular Sweden’s
Consortium for Artificial Photosynthesis. The photo biological part of that program is included in the
consortium for artificial photosynthesis. In Italy, the University of Padova is leading research into
innovative methods of hydrogen production from biological processes. The US photolytic program
focuses on both photo-biological and photo-electrochemical hydrogen production processes.

5.3. High temperature solar - Thermolysis
Thermolytic water splitting is the generic term for multi-step thermochemical processes that use
high-temperature heat to split water into hydrogen and oxygen. The interest in this route stems from
the theoretical potential that such a process could convert high-temperature heat into hydrogen with

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50 % efficiency, thereby outperforming the efficiency of the electricity/electrolysis pathway and
offering an alternative to electrolysis for renewable hydrogen generation. Over more than thirty years
of extensive research has lead to the identification of a handful process options. Thermolysis is
mostly proposed in the context of advanced nuclear reactors and features prominently in the
Technology Roadmap for Generation IV nuclear reactors. Alternatively, the high-temperature heat
from solar concentrators may be used. In any case the major challenge is the capture of the thermally
split hydrogen.

Direct thermolysis can be pursued at very high temperatures, exceeding 2000°C. The hydrogen
might be captured via membranes. Yet, it needs to be taken into consideration that other major
developments applying functional materials at high temperatures, as magneto-hydrodynamic power
generation or even the SOFC, revealed notable obstacles with such materials. Circumventing this
problem, hydrogen can be split at lower temperatures and captured applying a sequence of chemical
processes that allow in the end gathering the pure hydrogen. Reaction temperatures required for the
most promising thermochemical cycles are:
      Zink/ zink oxide process: hydrogen splitting reaction: 600°C; zink regeneration reaction:
     Sulphur iodine cycle: sulphuric acid decomposition: 800-1000°C; SO2 gas absorbing Bunsen
     reaction: 20-100°C; HI decomposition: 450°C
      UT-3 cycle: all steps at or below 760°C.
Side reactions need to be investigated and minimized. Use of gaseous or liquid noxious substances is
advised to avoid in these cycles if energy relevant mass markets are targeted. Research strategies for
thermolysis that devise pathways to get around these issues should be pursued for the high potential
of the technology. [SRA, 2005]

5.4. Photo-electrochemical production
Photo-electrochemical processes can produce hydrogen in one step – splitting water by illuminating
a water-immersed semiconductor with sunlight. This is basically the combination of photovoltaic
cells (PV) with in-situ electrolysis of water. In other words, the photovoltaic effect of semiconductor
materials is not used to generate electricity as in PV, but to directly split water electrochemically.

There are two types of photo-electrochemical processes:
   1. The first uses soluble metal complexes as catalysts. When these complexes dissolve, they
       absorb solar energy and produce an electrical charge that drives the water splitting reaction.
       This process mimics photosynthesis, however, currently there is minimal experience in this
   2. The second method uses semi-conducting electrodes in a photochemical cell to convert light
       energy into chemical energy. The semiconductor surface serves two functions, to absorb solar
       energy and to act as an electrode. However, light induced corrosion limits the useful life of
       the semiconductor.

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                         Fig. 8 Photo-electrolysis experiment [Riis, 2004]

It is still unclear whether the efficiency of photo-electrolysis efficiency might exceed that of an
integrated system of PV and electrolysis. Low cost silicon based photo-electrolytic systems have an
efficiency of 7.8%, while efficiencies of 16.8% have been achieved with a gallium based monolithic
system. The main advantage of a photo-electrolysis system is that it represents an advanced
alternative to a PV/electrolysis system by combining both processes in a single piece of apparatus.

Research into photo-electrochemical processes is limited but gaining momentum. Four major photo-
electrochemical concepts are being studied, comprising two-photon tandem systems, monolithic
multi-junction systems, dual-bed redox systems, and one-pot / two-step systems. While the first two
concepts employ thin-film-on-glass devices immersed in water, the latter two concepts are based on
the application of photosensitive powder catalysts suspended in water. The IEA-HIA coordinates and
manages a significant part of these R&D efforts in a collaborative, task-shared Annex. [IEA
HYPROD, 2005]

The US is developing advanced renewable photolytic hydrogen generation technologies, with a 2015
goal to demonstrate an engineering-scale biological system that produces hydrogen at a plant-gate
cost of $10/kg projected to commercial scale. The US is also planning to demonstrate direct photo-
electrochemical water splitting with a plant-gate hydrogen production cost of $5/kg projected to
commercial scale. [IEA, HCG, 2005] [SRA, 2005]

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6.1. Utsira
Norsk Hydro in cooperation with Enercon developed a combined wind and hydrogen energy system
as a pilot demonstration project on the island of Utsira, whose municipality has an ambition to be
self-supplied with renewable energy [Eide, 2005, Hagen, 2005].

                        Fig. 9 Overall view of the Utsira wind-hydrogen site

The island of Utsira is located 1 ½ hours boat trip off the western coast of the Norwegian mainland. It
has the smallest population of all municipalities in Norway (about 230 inhabitants) and a total area of
only 6.15 square kilometres. The island is presently connected to the main land through a sea cable,
but has a history of having diesel electric generation on the island. The wind-hydrogen option was
examined in order for Utsira to become self-supplied with renewable energy and at the same time
being independent of a cable to the main land in the future. The autonomous system developed on the
island aimed to cover the loads of 10 customers both in terms of peak load and energy consumption.
The power quality delivered by the autonomous system should be comparable to that supplied today
by the cable connection to the main land. Under these constraints and following detailed simulations,
the system consisted of the following components:

                             Key                Key data
                             Wind turbine       600 kW
                             Battery            50 kWh
                             Flywheel           5 kWh, 200kWmax
                             Synchronous        100 kVA
                             Electrolyser       10 Nm3/h, 48 kW
                             Hydrogen storage   12 m3 @ 200 bar = 2400
                             unit               Nm3
                             Hydrogen genset    55 kW
                             Fuel cell          10 kW

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The components making the autonomous system were integrated electrically at 400V (TN-S)
@50Hz. A separate 315 kVA, 22/0.4 kV transformer connected a 1.5 km cable, transmitting power
from the autonomous system to the customer substation. All the 10 households were connected in the
customer substation at 230V, which is the standard voltage level in Norway. The customer substation
also comprised a 22kV bus bar circuit breaker for easily switching the customer from autonomous
system mode to grid-connected mode in case of failure. Hence, an emergency mode for the customers
could then easily be provided, and requirements on autonomous system redundancy (and costs) could
be minimised.

The 600kW wind turbine connected to the autonomous system had a separate 300 kW one-directional
inverter drawing electricity from the DC circuit and fed into the autonomous system. Surplus power
was fed into the grid in parallel to the second turbine. The power fed into the autonomous system
varies in proportion to the total power produced from the wind. In practice, the autonomous system
has a ‘virtual’ 300 kW turbine connected to it.

The project concluded on the importance of placing emphasis on integration issues right from the
project’s start. More specifically, the main conclusions were:
    • Careful considerations with respect to static and dynamic performance of the hydrogen
        equipment (hydrogen loop) are needed
    • Interfaces in the electrical loop must consider quality demands on the consumer side
    • Interfaces in the control loop must be standardised. Different suppliers normally have
        proprietary control systems, thus it is vital to select a standard communication protocol in
        early design phase, preferably based on industry standards
    • Location, quality of supply, as well as maintenance philosophy must be included in the design

It should be noted that some problems have been encountered when trying to feed the local electricity
network through the fuel cells installed.

6.2. Stralsund
Fachhochschule Stralsund has established in the 90s a Multi-component Laboratory for Integrated
Energy Systems, that includes a variety of energy conversion devices that can convert renewable
sources of energy, such as wind and solar energy, to thermal or electrical energy. The key
components are listed below:

                             Key                Key data
                             Wind turbine       100 kW
                             Photovoltaics      10 kW
                             Electrolyser       20 kW operating at 25 bar
                             Hydrogen storage   200 Nm3
                             2 stage H2         at 200 bar
                             PEM fuel cell      350 W
                             catalytic H2       21 kW

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The wind turbine has a nominal power output of 100 kW. However, depending on the wind speed,
the two-speed asynchronous generator can be operated at either 1,000 or 1,500 rpm, producing 20
kW or 100 kW of electricity, respectively. Nominal power of 100 kW is reached at a wind speed of
12 m/s. The 20-kW alkaline pressure electrolyser was developed by ELWATEC GmbH Grimma, that
later became Hydrogen Systems GmbH. It can deliver hydrogen at up to 25 bars. The system
comprises 40 cells characterized by a very compact bipolar design.

The hydrogen storage tank has a geometrical volume of 8 m3 . However, because the system works
without a compressor, the tank is only used to the maximum pressure of the electrolyser. Under 25
bars, the tank is filled within 50 hours and contains 200 Nm3 hydrogen. A two-stage compressor with
an output pressure of 300 bars is available for filling up tanks or bottles.

The static and dynamic behavior of the electrolyser has been investigated in this facility. The
efficiency of the electrolyser stack reached about 80% on a HHV basis. The electrolyser was
controlled according to the power output of the wind turbine.

             Fig. 10 the 20 kW high pressure electrolyser of ELWATEC GmbH Grimma

Besides providing a suitable environment for engineering students experiments, the installation has
produced interesting data as to the capability of an electrolyser to operate with intermittent electrical
loads. Dump loads are advised for stable autonomous operation [IEA web site on case studies]

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6.3. RES2H2
The integration of wind and hydrogen technologies at an industrial scale is the aim of the RES2H2
EC funded project (contract ENK5-CT-2001-00536). The project involves the realisation of two test
sites, one in the Canary islands, Spain and another in Attica, Greece. The Spanish test site aims to
optimise the energy produced by a wind turbine by providing electricity to the grid, producing
drinking water through a reverse osmosis plant and hydrogen through an electrolyser. This will be
stored in a tank and used in a fuel cell for re-electrification purposes. The aim of the Greek test site is
to study the possibility for hydrogen to become an alternative product for wind park developers, in
case electricity transmission lines are saturated, studying at the same time the performance of
hydrogen production and storage technologies under variable power input. [RES2H2 web site,
Lymberopoulos, 2004]

The Spanish test site has encountered some siting and optimisation problems and is presently (2005)
under design. The Greek test site has been realised and is about to be commissioned. Its main
parameters are listed in the following table:

                               Key                 Key data
                               Wind turbine        500 kW
                               Electrolyser        25 kW operating at 25
                               Hydrogen            40 Nm3 in MH tanks
                               1 stage H2          at 220 bar
                               1 filling station   220 bar bottles

For the Greek test site of RES2H2 a Casale Chemicals 25 kW electrolysis unit operating at a pressure
of up to 20 bar has been connected to a 500 kW gearless, synchronous, multipole Enercon E40 wind
turbine. The electrolysis unit has been developed with special cells to be able to withstand rapid
changes of input power (15-100% capacity in 1 sec). The electrolyser will operate in various modes
(percentage of wind turbine production, "peak-shaving", etc.), with excess energy from the wind
turbine being fed to the grid. The electrolytic hydrogen will be purified prior to entering a buffer
tank. Part of the produced hydrogen will be stored in novel metal hydride tanks of approximately 40
Nm3 H2 capacity. The rest of the produced hydrogen will be compressed to 220 bar and fed to
cylinders at a filling station. The process flow sheet is shown in figure 11, while figure 12 shows an
overall view of the installation.

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                                                                                                           Hydrogen                                 11
                        O2 vent                                       H2 vent                                 HC                                                                                                     12
                         10                                            11                                                                                                                                                                    CWout

                                                                                     PI               AI                                                                                                            PC TC
                                                                                                                 DO                                HD                                            MHT

                                                                                                                                                                                               Metal Hydride
             Oxygen                                       Hydrogen                                                                                                                               Tank
              Filter      OF                                 Filter     HF

                                     10                                           11
                                                                                                                                                                                                               TC               CWin

           CWout                                                                 LC
                                   LC                                                                                                                                                                                           Electrical       CWin
              OS                                                HS                                                                                                                                                               Heater
         Separator                                       Hydrogen                          CWin                                                                                                                                                                 H2 vent
                                                         Separator                                3

                                                                                                                                                                        PC    TC          12
                                                                                                                                                   PCV                                          PCV

                                          Electrolysis                                                                                                                   H2 Buffer tank

            Legend                                                                                                                                                                                                                                      Cylinders' Filling Station
            CW: Cooling Water
            DW: Demineralised Water                                                         Water Tank                                                   Water inlet
            PI: Pressure Indicator                                                                                              Water demineraliser                                                             Compressor
            PC: Pressure Controller                                                                                                                                                                                               Compressor
            TI: Temperature Indicator                                                                                                                                                                                        PC Cooler                  TC
            TC: Temperature Controller
            AI: Analysis Indicator
            CV: Control Valve                                                             CW in, T, P, m3/h
                         Battery Limits                                                                3              4         5              6           7

                1 : DW inlet               10 : Oxygen vent
                                                                                                      HS              HC       MHT            MHT        CC
                 2 : Air inlet             11 : Hydrogen vent                                         OS
           3 - 7 : CW inlets               12 : Hydrogen vent
                                                                                                                                                                  CW out, T

Fig. 11 Process flow sheet of hydrogen production, storage and compression system [Varkaraki

                                                    Fig. 12 Overall view of the wind – hydrogen installation

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The various components of the system have all been installed, including the electrolyser, compressor,
metal hydride tanks, cooling unit, control cabinets. The metal hydride tanks have been activated and
the compressor has been primed with Nitrogen. Initial trials will commence in October 2005 upon
which time the electrolyser will be commissioned.

Conclusions drawn so far with respect to designing and building such an installation are:
   • besides meeting technical and cost targets and addressing safety issues, the design of a
      hydrogen energy system must be done in relation to what is market ready – no point to
      optimise a system specifying units whose capacity is not available or that are still at an early
      development phase
   • the transportation and installation of hardware is something to be considered for such
      installations that are in many cases remote and with poor access. The capacities of the
      systems involved in the present site were on the limit of conventional trucks and lifting
      equipment in terms of size and weight in combination with the poor access road quality
   • the interfacing of the various units is key, in relation to static and dynamic hydrogen flow,
      electricity and information flow and control. In the present system:
   • parameters such as the flow rate, pressure and temperature of hydrogen were used for the
      hydrogen interfacing of the hardware at the low pressure (20 bar) part of the system
   • dynamic effects are of the order of 1 Hz. An analogue input was specified on the electrolyser
      in order to specify the current, based on the output of the wind turbine and the control strategy
   • a PLC based control system was preferred to a PC based one for reasons of safety, resulting
      however to reduced flexibility in implementing changes in situ
   • special attention must be paid to peripheral units, vital for the safe operation of the system,
      including cooling water, instrument air, Nitrogen inertisation. A closed cooling water system
      was preferred since in such remote locations water availability is limited
   • the fact that the installation is remote and exposed means that provisions must be taken in
      protecting the hardware from nature’s elements, from theft and even from wild animals

6.4. FIRST project
INTA of Spain has since 1990 developed in three phases a PV-hydrogen installation in order to study
the feasibility of solar hydrogen production and storing solar energy in the form of hydrogen. The
main components of the plant that was developed are listed below:

                             Key                Key data
                             Photovoltaics      8.5 kW
                             Alkaline           5.2 kW operating at 6 bar
                             TiMn2 MH           24 Nm3
                             Hydrogen storage
                             2-stage            8.8 Nm3 at 200 bar
                             compressor and
                             bottle storage
                             one PAFC           10 kW
                             two PEM FCs        2.5 and 5 kW

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The electrolyser manufactured by METKON (fig. 13) is equipped with an adjustable control unit that
allows both automatic and safe operation, and different operation modes. To provide optimum direct
coupling with the PV field, the control unit can select the number of operating cells as a function of
the solar radiation:
    • 24 cells: 120-90 A (1000-720 W/m2)
    • 25 cells: 90-60 A (720-500 W/m2)
    • 26 cells: 60-30 A (500-200 W/m2),

                       Fig. 13 5.2 kW METKON alkaline electrolyser of INTA

The hydrogen produced by the electrolyser is initially stored in an intermediate buffer of 1 m3 water
volume, from which it can be transferred to one of the two storage systems: metal hydride storage or
pressurized gas (at 200 bar), shown in figure 14. The metal hydride storage system manufactured by
GfE mbH consists of an intermediate buffer, a hydrogen purification unit, a metal hydride container
and a cooling water supply system.

 Fig. 14 Hydrogen storage facility of INTA (from L to R: buffer tank, MH tank, 200 bar bottles and

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With respect to the fuel cells installed, a 10 kW PAFC supplied by ERC was installed at the end of
1993 that included a methanol reformer to permit operation with methanol so as to allow tests with
fuels other than pure H2.

Lastly a number of auxiliary systems have been installed for the proper operation of the system,
    • Feed water treatment unit
    • Gases supply section
    • Fire protection system
    • Uninterrupted power supply
    • Cooling/heating water supply unit

The control system of the facility was designed in a decentralised way, so that each subsystem had its
own independent control system.

Some of the observations from the long-term operation of the previous experimental facility are:
   • the efficiency of the PV array was 8.3% and of the electrolyser 69.6%, with an overall
      efficiency of 5.7%
   • the electrolyser operated with higher efficiency under varied number of cells operation
   • no deterioration of the electrolyser performance was observed , however, the long time
      required to reach operating temperature (2 hours for steady state operation) meant that
      efficiency was low in this period of operation.
   • a lack of components of such capacities that would allow the optimal design of small scale
      stand-alone systems was observed

6.5. ENEA wind- hydrogen stand-alone system

The “Hydrogen Generation from stand-alone wind powered electrolysis systems” EC project
(contract number JOU2-CT94-0413) was realised between 1994 and 1997 and aimed to study the
integration of wind energy technologies with electrolysers, in order to complement the numerous
studies investigating PV-based hydrogen production. The project sought to determine how best to
control a wind turbine to produce a smooth power output, to examine the tolerance of an electrolyser
to fluctuating power inputs, and to design and build a small scale (< 10 kW) stand-alone wind
hydrogen production system. The main components of the system are listed in the following table:

                         Key               Key data
                         Wind turbine      Riva Calzoni M7S, 5.2 kW
                         Alkaline          von Hoerner System GmbH,
                         Electrolyser      2.25 kW, 20 bar
                         battery storage   330 Ah
                         dump loads        0.5 and 2 kW

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The plant comprised the wind turbine, the electrolyser unit complete with its built-in controllable
power supply, battery storage, a DC-DC controllable converter, and two dump loads (0.5 and 2 kW)
controlled by two voltage-actuated relays. The auxiliary equipment (electrolyser pumps, valves,
control equipment, and water demineralization unit) for the demonstration plant were supplied by the
grid for convenience. The following figure shows a schematic of the plant layout.

                         Fig. 15 Stand-alone wind-hydrogen system layout

The plant could be operated in 2 modes, with respect to electrolyser loading:
   1. wind-powered: The electrolyser current is controlled by the DC-DC step down converter,
       while the current to the battery storage was not controlled, with the battery acting as an
       energy buffer, and the dump loads were controlled in order to limit the maximum voltage to
       the battery to prevent overcharging
   2. controlled power supply: The electrolyser is supplied by the controllable power supply, either
       manually or PC-controlled to emulate the operation from a different type of plant

Both hydrogen and oxygen were released to the atmosphere. The control components of the plant for
its autonomous operation included:
     • wind turbine centrifugal speed controller
     • wind turbine voltage controller
     • dump load controller
     • electrolyser controller
     • plant controller (controls the connection state of the electrolyser to the DC bus and the
        amplitude of current supplied to the electrolyser)

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The system’s control was based on the state of charge (SOC) of the battery. When the battery SOC
was low, energy produced by the wind turbine was used to recharge the battery. Once this was full,
then energy was directed to the electrolyser.

The first year of the system’s operation was spent on correcting a number of faults and malfunctions
related to the electrolyser operation. Most of the problems were due to high impurity levels of
hydrogen in oxygen during operation at low current levels and apparently high impurity levels of
oxygen in hydrogen after some hours of stand-by operation, both conditions leading to alarms and
automatic plant shutdown. Most of these problems were related to leaking flanges or pipes and were
addressed through tightening or pipe substitution. The problem that persisted was the bad oxygen
quality at low currents. This was addressed through better anode insulation (performed by the cell
stack manufacturer). Following these modifications tests showed that:
    • behavior in intermittent operation is satisfactory, although during stand-by, the pressure drop
        is not negligible (approximately 15 bar in 60 hours)
    • the measured minimum continuous current level for acceptable oxygen quality (defined as 3
        % hydrogen in oxygen) is around 25 A (irrelevant if oxygen is vented)
    • hydrogen quality is good, with impurity levels typically of the order of 0.15-0.35% oxygen in
        hydrogen, for current levels as low as 15 A or less, thereby permitting operation at very low
        capacity factors

The overall cell stack efficiency (relative to the lower heating value for hydrogen) has been found to
be typically around 40%, with a maximum of 45% around nominal current. These values are very
low compared to the values in excess of 60% found for other cases like the HYSOLAR Electrolyser 2
at DLR. Operation of the DLR electrolyser with intermittent loads proved that:
    • for short term operation, power fluctuations have no significant effect on the overall electrical
       stability of the electrolyser
    • the magnitude of pressure fluctuations increases and the product gas purity declines,
       compared to operation at the equivalent constant mean power input
    • the decline in product gas purity appears to be affected by power variations on the scale of a
       few minutes rather than a few seconds

The project concluded that electrolyser technology was relatively immature for such wind-hydrogen
stand alone applications and that the electrolyser cost should be considerably reduced if such systems
were to be used to cover cases with excess wind energy in weak grids.

The HYSOLAR project was carried out by DLR and the University of Stuttgart in cooperation with
three Saudi universities. Phase I of the program lasted from 1985 to 1989 and consisted of the
following activities:

   •   design and installation of a 350 kW demonstration plant in the "Solar Village" near Riyadh
       consisting of a concentrating photovoltaic power system, an advanced electrolyser system
       with power supply system, a grid operated rectifier and the necessary gas handling and
       storage system in order to collect experience in technical scale application

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   •   design and installation of a 10 kW test and research facility in Stuttgart, consisting of a multi-
       crystalline photovoltaic generator system, a power conditioning system, two electrolysers of
       10 kWe and one electrolyser of 2 kWe and a PV-simulator in order to do systems development
       for advanced hydrogen equipment

   •   undertaking of basic research and of system studies for the assessment of the HYSOLAR
       program and of a utilization program for the evaluation of safety, reliability and
       environmental aspects of the selected hydrogen application technologies, as well as of an
       educational and training program

Fig. 16 The 350 kW electrolyser in Riyadh (left) and the Stuttgart HYSOLAR building(right)

Phase II lasted from 1992 to 1995 and its major focus was on hydrogen production and utilization. In
particular, the 350 kW electrolysis demonstration plant in Riyadh was put into continuous solar-
connected operation. From the long-term experience accumulated, performance data were obtained
for optimisation and scale up of the system. In the 10 kW research and test centre in Stuttgart, several
different electrolyser concepts have been investigated. For solar operation the electrolysers could be
connected to the photovoltaic generator with or without power conditioning unit. Furthermore the
electrolysers could be operated with any other controllable current or power profile fed by grid
connected power supplies, thus simulating wind energy profiles from wind turbines located at
different sites worldwide. A comprehensive simulation code to calculate system efficiency and
annual hydrogen production rate from individual characteristics of components and climatic data has
been developed.
In the field of hydrogen utilisation technologies basic theoretical and laboratory research was
performed on alkaline fuel cell concepts (e.g. characterization of gas diffusion electrodes) as well as
on catalytic burners (reaction kinetics of H2/air mixtures). Experimental investigation of instationary
combustion phenomena were performed. Practical tests were carried out on internal combustion
engines, also of the compression ignition type. [Altman, downloadable from
http://www.hyweb.de/Wissen/autarke.htm], [IEA/H2/T11/FR1-2000]

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The Stand Alone Small Size Photovoltaic Hydrogen Energy System (SAPHYS) project was a joint
undertaking of ENEA, IFE and KFA, funded by the EC under Joule II (1994 – 1997). SAPHYS was
conceived to test and demonstrate safe and effective long-term storage of hydrogen produced by
renewable energy using solar powered electrolysis of water, and to regenerate the stored energy into
electric energy with a fuel cell.

The objectives of the project were:
· to assess the efficiency of hydrogen used as a storage medium of solar electric energy
· to design and test a small SAPHYS system for unattended operation.

The main components of the system are shown in the table below:

                             Key                Key data
                             Photovoltaics      5.4 kW
                             Electrolyser       5 kW operating at 20 bar
                             Hydrogen storage   300 Nm3
                             PEM fuel cell      3 kW
                             dummy loads        4 kW peak

The electrolyser (manufactured by Metkon-Alyser with cells by KFA) was originally 2.5 kW and was
revamped to 5kW by Casale Chemicals. Emphasis was placed on good dynamic performance in
intermittent operation. The SIMWELLY software of the Research Centre Julich was used to design
and optimise the 5 kW electrolyser. An efficiency of 87% at 80 C was calculated for this electrolyser
and the particular electrodes used (activated nickel electrodes and NiO diaphragms).

The fuel cell was a Ballard Power Generator System (PGS) 103A solid polymer fuel cell (SPFC)
rated at 3 kW DC power, with air as oxidant, designed mainly for demonstration and evaluation. Its
main features were: the capability to operate at low temperature (about 72°C); its short start-up
period; no significant stand-by problems; its simple installation and operation; its quick response to
load changes; and its high efficiency. The system was built to cover the energy needs of two
hypothetical isolated houses whose load profile was characterized by small and short hourly peaks of
about 0.4 kW and two high consumption peaks (4 kW in the morning and 2.5 kW in the evening).
The daily energy consumption was 11 kWh, obtained through dummy loads.

Emphasis was placed on integrating the various components of the system through simulations,
suitable design of the electrolyser and the control system, usage of a battery bank for stabilising
voltage. The control strategy was based on an algorithm that operated the electrolyser and fuel cell
according to the battery state of charge.

Some observations from operating the SAPHYS plant were:
   • the plant was very complex, the presence of many components increasing the parasitic energy
      consumption and could reduce plant reliability

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   •   the DC-DC converters configuration protected the electrolyser from fast voltage fluctuations
       at the bus-bar level but introduced inefficiencies
   •   The presence of the battery produced a smooth current profile to the electrolyser, even during
       temporary periods of low or irregular insolation
   •   using the battery state of charge as the variable to operate the electrolyser and fuel cell,
       allowed for smooth equipment operation, and in the case of the electrolyser, a high-current
       operation with high grade purity hydrogen production.
   •   the auxiliary equipment of the electrolyser proved to be less reliable than the electrolyser
       itself. (water demineralization unit, compressed air treatment unit, inert gas unit)
   •   the solid polymer fuel cell proved suitable for a small-scale system, however, it can suffer
       from long stand-by periods and from freezing temperatures.

The testing phase proved that both electrolyser and plant efficiencies were very encouraging and
compare well with those obtained in similar experiences. The PV array provided a little over one
third of its energy to the load (439 kWh) and two thirds to the electrolyser to make hydrogen (768
kWh). A total of 123 Nm 3 of hydrogen were produced during the two-month test period. Figure 17
shows the daily behaviour of the plant for a day with significant variations of solar input.

                  Fig. 17 Experimental data of the SAPHYS system for a cloudy day
It can be seen that the type of control logic used (battery state of charge) makes the battery a buffer,
smoothing the input load to the electrolyser. The measured efficiency of the electrolyser was 77% but
for operating temperatures below the design value.

The project concluded that it would be beneficial to use a reversible fuel cell (electrolyser and fuel
cell in one device, preferably pressurised) in order to reduce the systems complexity and cost.

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6.8. SWB project
This is one of the earliest and largest projects of its kind. It was initiated in 1986 and completed in
1999 with a budget of DM 59million (US$ 39 million). The aim of the Solar-Wasserstoff-Bayern
(SWB) hydrogen project was to test, on an industrial demonstration scale, major technologies of the
hydrogen cycle utilizing electric power generated by photovoltaic solar energy. The facility was
located in Neunburg vorm Wald, Germany.

                          Fig. 18 Arial view of SWB solar hydrogen facility

The following table shows the capacities of the various subsystems

                           Key Components          Key data
                           Photovoltaics           370 kW
                           two low-pressure        111 kW and 100 kW
                           Alkaline                with a joint production
                           Electrolyser            capacity of 47 Nm3/hr
                           one high -pressure      100 kW operating at 32
                           Alkaline                bar producing 20 Nm3/hr
                           compressors for H2      30 bar delivery pressure
                           and O2
                           H2 storage              5,000 Nm3
                           O2 storage              500 Nm3
                           two NG-H2 boilers       20 kWth each
                           NG-H2 catalytic         10 kWth
                           H2 catalytically        32.6 kWth burner, 16.6
                           heated refrigeration    kWth       refrigeration

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                           unit                  capacity
                           AFC                   6.5 kW
                           PAFC                  79.3 kWe 42.2 kWth
                           PEM                   10 kW
                           filling station       Liquefied H2

In building the SWB system, emphasis was placed not only on the previously mentioned major
components, but also on the essential subsystems / peripherals / balance-of-plant, including utility
and auxiliary subsystems (instrument/operating air supplies, nitrogen supply, demineralised
water/KOH systems, ventilation, e.g.), process and safety control subsystems, and extensive test data
acquisition subsystems. Also to power conditioning (converters and inverters) as a way of improving
the operability and efficiency of the overall system.

At SWB, particular attention was paid to the integration of the components and to the operability of
the facility as an integrated plant. Some of the coupling issues investigated in detail were:
    • The electricity produced by the photovoltaic fields was distributed and/or transformed
        according to downstream needs. Surplus PV electricity was supplied to the grid, while
        electricity supply from the grid was used in other cases. Direct coupling of solar generators
        and electrolysers was also possible.
    • Generation, treatment and storage (G/T/S) of hydrogen and oxygen were adjusted to the
        downstream needs
    • Each of the various end use applications possible in the SWB facilities (i.e., production of
        heat, cold, or mechanical power) requires its own mixture of hydrogen, natural gas and
        oxygen and its own combination of G/T/S subsystems.

All possible varieties and many desirable combinations of applications, including different choices of
solar generators or electrolysers were tested. The cumulative operating times logged for the various
plant subsystems differ considerably according to the test programs run (i.e., alkaline low-pressure
electrolyser 6000 h, membrane electrolyser 2000 h, catalytic heater 5200 h, PAFC fuel cell plant
3900 h, LH2 filling station 900 h).

With respect to the operation of the atmospheric pressure electrolysers, hydrogen purity problems
occurring with the alkaline electrolyser, were eliminated by installing polysulphone diaphragms
reinforced on the cathode side to replace the previous plain type. Test results gathered over several
years indicate that the alkaline low-pressure electrolyser worked well. The membrane electrolyser
had to be shut down in June 1995 because of increasingly deficient product gas purities (above all, H2
in product O2). Up to the time it was decommissioned, the membrane unit also worked well even
under conditions of greatly varying power input when directly coupled to a solar generator. After
dismantling the cell stack in February 1996, the membranes were found to have deteriorated severely
during the five years of test operation.

The advanced 30 bar 100 kW alkaline electrolyser provided the same specific energy consumption
(4.5 to 4.7 kWh/Nm3) but no compression of the produced gases was required. Some problems were
encountered with rising O2 presence in the produced H2 leading to a change of the cell stack.

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Following cleaning and drying, the gases were stored in respective tanks. The system had the
capability to provide mixtures of hydrogen and natural gas to the various heaters or fuel cells.

The alkaline fuel cell was operated on pure H2 and O2 and an efficiency of 54% was measured at
rated load but the system proved too complex and its reliability was questionable, with frequent
replacements of the cell stack.

The PAFC was run on natural gas or hydrogen, using air as the oxidiser, which was enriched by O2
(50%) for improved efficiency (3%). Major problems occurred at the time of commissioning of the
PAFC plant, necessitating extensive repairs and changes. Most of the difficulties originated in the
associate peripheral systems, with very few in the fuel cell stack itself. Emissions were measured to
be comparable with other commercially available phosphoric acid fuel cell plants and were several
orders of magnitude lower than the levels specified for gas engines. The frequent starts and stops
(450 in total) lead to a drop of its nominal power by 20 kW.

General conclusions were:
   • hydrogen systems for energy conversion are for the most part only to be purchased at the
      present time as prototypes or individually engineered designs.
   • their integration into a meaningful overall plant concept is often more difficult than
      commonly believed. For instance, the extent and complexity of the associate peripheral
      systems is often underestimated
   • The multitude of necessary utility and auxiliary systems required underscores the fact that
      large capacity hydrogen facilities are plant engineering and construction projects subject to
      individual planning
   • Closely centralized generation and storage of the gas and its subsequent utilization as an
      energy medium is mandatory not only in the interests of cost reduction but also with a view to
      optimum attendance, service and safety installations.
   • it is desirable that major plant subsystems for gas generation and utilization be constructed as
      outdoor installations, unlike the indoor configuration selected for the SWB.
   • On the whole it can be stated that several of the systems installed at the solar hydrogen
      facility failed to work satisfactorily at the start but most problems were addressed and in the
      process many improvements to the original concepts were achieved


The PHOEBUS project involved the provision of autonomous solar electricity to the library building
of the Research Centre Julich. This system included batteries but also an electrolyser and a fuel cell,
as can be seen in the following table:

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                              Key                Key data
                              PV                 43 kW
                              Batteries          110 batteries storing
                                                 300 kWh
                              Electrolyser       26 kW operating at 7
                              Electrolyser       5 kW operating at 120
                              Experimental       solar thermal - metal
                              compressor         hydride 120 bar
                              Hydrogen           3000 Nm3 in H2
                              storage            cylinders at 120 bar
                              Oxygen storage     1400 Nm3 in O2
                                                 cylinders at 70 bar
                              Alkaline fuel      6.5 kW

      Fig. 19 General view of the PHOEBUS facility (left) and the 120 bar electrolyser (right)

The stability and controllability of direct coupling of the PV generator with the battery, electrolyser,
and fuel cell have been thoroughly investigated in the PHOEBUS facility and feasibility was
demonstrated by simulation. It was concluded that the efficiency of the overall plant can be improved
from 54% to 65% and an appreciable reduction in construction costs may also be expected by the
omission of the converters.

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6.10. PURE project
The Stand-Alone Small Size Wind Hydrogen Energy System (PURE) Project was a joint project of
UNST (community of the Shetland Islands), siGEN (system integrator), AccaGen SA for the PURE
Community of Shetland-Islands, and is supported by the EU. The project aims to demonstrate how
wind power and hydrogen technology can be combined to provide the energy needs for a remote
rural industrial estate. PURE was conceived to test and demonstrate safe and effective long-term use
and storage of hydrogen produced by renewable energy using wind powered electrolysis of water,
and to regenerate the stored energy into electric energy with a fuel cell. The key components of the
system are listed below

                              Key                Key data
                              Wind turbines      2 15 kW wind turbines
                                                 (Proven Ltd)
                              Electrolyser       15 kW operating at 55
                                                 bar (Acca Gen SA)
                              Hydrogen           44 Nm3 in H2 cylinders
                              PEM fuel cell      5 kW (Plug Power)

A picture of the site is shown in the figure below:

                           Fig. 20 view of the PURE wind hydrogen system

The electrolyser section consists of a AccaGen electrolyser unit assembled with advanced cells
specifically designed and manufactured by AccaGen SA for Wind application, capable of operating
up to 55 bar. Apart from high energy efficiency and good dynamic performance in intermittent
operation, a particularly important requirement for Wind-operated water electrolyser is the possibility
of operating the electrolyser over a wide range with high current yields and sufficient gas purities.

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To match the actual plant power, the electrolyser is designed for 15 kW, the required power
according to the design data specified from simulations. This was done in cooperation with siGEN
LtD. Furthermore, the electrolyser control is developed by AccaGen to ensure fully automatic
operation within the PURE system. The start-up of the system is planned for September 2005.

6.11. PVFSYS (Sophia Antipolis)
The aim of the PVFSYS EC funded project (contract ERK5-CT1999-00017) was to develop a PV
and hydrogen based system for storing solar energy. The hydrogen part of the system consisted of an
electrolyser, hydrogen storage and a fuel cell. The system aimed to avoid using batteries, thus fuel
cells were to the only means to provide electricity to the load, if that exceeded the PV production. A
small battery was used for the safe shut-down of equipment in case of emergency. The PV-FC system
can thus be considered as a direct competitor to PV-batteries concept. [Lymberopoulos 2005]

Two systems were built, one defined as a test bench in Sophia Antipolis and the other a pilot plant
located in Agrate. The main components of the two systems are listed below

                Key                Key data                  Key data
                Components         Sophia Antipolis          Agrate
                PV                 3.6 kW                    3.6kW
                Electrolyser       3.6 kW 10 bar alkaline    3.4 kW 30 bar alkaline
                Hydrogen storage   400 l in cylinders        4Nm3 in tank
                Oxygen storage     200 l in cylinders        -
                PEM fuel cell      4 kW (DeNora)             2 kW (Axane)

The main difference between the two systems is the fact that oxygen is stored in the test bench and
used in the fuel cell, increasing efficiency but also space and safety measures requirements.

  Fig. 21 The 3.6 kW Electrolyser (left) and 4kW fuel cell (right) of test bench of PVFCSYS system

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Intrinsic tests were performed on the electrolyser and fuel cell of the test bench system for their
characterisation (electrical and thermal behaviour, faraday efficiency, gas purity). Additionally
simulations were performed using the Matlab/Simulink software in order to develop a numerical
model for such a kind of “reversible fuel cell”. The system storage efficiency was estimated at 40-

The conclusions of the project in terms of improving its components were:
   • Increase pressure of electrolyser to reduce the storage volumeReduce the intrinsic
       consumption of the electrolyser through more efficient auxiliary components (valves, pumps)
   • Reduce pure water consumption of electrolyser to zero by optimising the security
       measurement (gas purity)Reduce price and increase range of commercial electrolysersReduce
       the intrinsic consumption and increase the life time of the fuel cells

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Hydrogen and fuel cells have received increased attention in Europe in order to help meet policy
objectives at a European Union or member state level. The following table shows the level of funding
for hydrogen and fuel cells under the 5th Framework Programme.

              Table 6 Budget in MEuros allocated to H2 and FC projects under FP5

Similarly in the 6th Framework Programme, the EC has approved for funding the following projects,
with an indicative EU funding of 60.8 MEuro.

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                   Table 7 H2 Projects funded by EC under FP6 [Bermejo, 2004]

In the field of Hydrogen and Fuel cells the European Commission has helped the launch of the
Hydrogen and Fuel Cells Technology Platform. This platform has been a major instrument for
steering EU efforts in this field and it is expected that in the context of FP7, the Platform will evolve
into a Joint Technology Initiative, a new kind of framework for fostering technological development
through public private partnerships.

Some of the EC funded projects that are related to Hydrogen from Renewables are listed below.

7.1. EC funded projects
BIO-H2, ERK6-CT-1999-00012 (completed)
This project aimed at developing a method for the production of H2 from biomass derived ethanol,
with “zero” emissions of pollutants. The method basically consisted of developing a bio-ethanol
reformer. The produced H2 was to be fed to FC powered vehicles. In the context of the project
catalytic    materials      for    the     reformation   of    bioethanol      were    developed
exhibiting high activity, high selectivity towards H2 formation, resistance to poisoning by S- and N-
containing species, and long-term thermal stability at temperatures in the range of 700-1000 degrees
C. The catalyst was deposited on ceramic foams in order to obtain the optimum catalytic surface.
Catalytic materials were also developed for the Water Gas Shift reaction in order to fit the operating
reactor conditions (temperature and pressure of the effluent of the primary reformer). Similarly
catalytic materials for the Selective Oxidation of CO were developed.
Coordinator: Gianlucca BOLITO

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Tel:+ 39-01-19083290
Fax:+ 39-01-19083786
e-mail: gianlucca.bollito@crf.it
EC scientific officer: A. Paparella

CHRISGAS, “Clean Hydrogen-rich Synthesis Gas”, FP6 project
An existing biomass-fuelled pressurised IGCC plant will be used as a pilot facility so as to test new
process equipment that will allow the production of a hydrogen-rich clean gas.
Coordinator: University of Vaxjo, Sweden
Contact e-mail: -
Project web site: www.chrisgas.com

RENEWABLE-H2, ENK5-CT-2002-80633 (completed)
The aim of this project was to make an overview of activities in Europe on renewable hydrogen and
to identify the role that renewable hydrogen could play in communities.
Coordinator: Bert VAN DE BELD
e-mail: vandebeld@btg.ct.utwente.nl
EC scientific officer: W. Borthwick

SUPERHYDROGEN, ENK6-CT-2001-00555 (on-going)
The project aimed at developing a supercritical water gasifier, that would be cost-effective (<
12Euro/GJH2) and energy efficient (>60%) for the conversion of wet biomass to compressed, pure
hydrogen (>98%Vol). The work involved theoretical modelling and bench-scale tests and included a
techno-economic evaluation of the chain.
Coordinator: Bert VAN DE BELD
e-mail: vandebeld@btg.ct.utwente.nl
EC scientific officer: G. Guiu Exteberria

HYDROSOL, ENK6-CT-2002-00629
The aim of this project is to exploit solar energy for the catalytic dissociation of water and the
production of hydrogen. The basic idea is to combine a support structure capable of achieving high
temperatures when heated by concentrated solar radiation, with a catalyst system suitable for the
performance of water dissociation and at the same time capable of regeneration at these temperatures,
so that complete operation of the whole process (water splitting and catalyst regeneration) can be
achieved by a single solar energy converter. The purpose of HYDROSOL is thus two-fold: 1)
development of novel catalytic materials for the water dissociation reaction at moderate temperatures
(800-1100 C) and of the associated coating technology on supports, and 2) integration of the
developed material technologies into a solar catalytic reactor suitable for incorporation into solar
energy concentration systems, opening the road towards a complete hydrogen fuel production unit
based solely on solar energy.
Coordinator: Aerosol & Particle Technology Laboratory, Chemical Process Engineering Research
Institute (CPERI), Centre for Research & tecnology Hellas (CERTH)
Project web site: http://www.hydrosol-project.org/

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RES2H2, EVK4-2001-00058
The aim of RES2H2 is the integration of wind and hydrogen technologies at an industrial scale. The
project involves the realisation of two test sites, one in the Canary islands, Spain and another in
Attica, Greece. The Spanish test site aims to optimise the energy produced by a wind turbine by
providing electricity to the grid, producing drinking water through a reverse osmosis plant and
hydrogen through an electrolyser. This will be stored in a tank and used in a fuel cell for re-
electrification purposes. The aim of the Greek test site is to study the possibility for hydrogen to
become an alternative product for wind park developers, in case electricity transmission lines are
saturated, studying at the same time the performance of hydrogen production and storage
technologies under variable power input. The Greek test site is completed and ready to be
commissioned (autumn 2005) while the Spanish site is still in the design phase due to various
Co-ordinator: INABENSA and then ULPGC
Project web site: www.res2h2.com
EC officer: J. Bermejo

7.2. National research efforts
The R&D efforts in the field of Hydrogen from Renewables is presented below per European country
[IEA, HCG, 2004]

Austria is one of the pioneers in the field of fuel cells, where even in the 1970s a vehicle equipped
with an alkaline fuel cell supplied with pressurised hydrogen was developed. Work in the field of H2
and FCs has primarily been “horizontal” across a number of broader R&D activities. There is no
“specific” fuel cell and hydrogen programs, however there are 50 ongoing H2 and FC projects being
conducted in Austria. In total, up to 40 Austrian organisations are carrying-out hydrogen and fuel cell
R&D activities. The Austrian R&D is mainly driven by third party funds (i) from the Austrian R&D
public and/or private funds, and (ii) from EU framework program budgets.

Concerning hydrogen production pathways Austrian research institutions mainly focus in the
hydrogen production from renewable energy sources through reforming (from biogas, biomass and
PV/electrolysis). Extensive modelling activities concerning the prospects of a hydrogen economy
(incl. fuel cells) in a future energy system are carried out by the International Institute for Applied
Systems Analysis.

Although there is no specific national R&D program, Belgium in working on a number of individual
projects to explore the potential of hydrogen and fuel cells. Belgium is also a participant in several of
the EU programs, while Belgium is home of part of the Air Liquide Industries hydrogen grid
covering Belgium, the North of France and the South of the Netherlands that connects chemical
industries and oil refineries.

With respect to hydrogen production from renewables, the Walloon government is supporting the
BIO-H2-FC project dealing with biological production of hydrogen for fuel cells from organic

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Denmark has a significant R&D community engaged in national, Nordic and European R&D
activities related to hydrogen and fuel cells. Energy research on hydrogen and fuel cells has in the
last five years been supported by the National Energy Research Program (EFP), the Public Service
Obligation Funds for R&D within environment and electricity (PSO), the Research Councils, and the
Hydrogen Program (1999-2001). The latter gave priority to pre-competitive research and
demonstration projects in hydrogen technologies and development and application of PEM fuel cells
for both stationary and mobile applications. So far no strategy has been made for hydrogen, but the
Danish Energy Agency is currently preparing a Danish hydrogen R&D strategy together with key

Most national and EU projects involving Danish companies in the field are related to fuel cells. Some
of the Nordic energy research projects are related to hydrogen, namely:
    • Biohydrogen (Roskilde University (DK), University of Jyväskyla (FIN), Tampere University
        of Technology (FIN), University of Akureyri (IS), Norwegian Institute of Water Research
        (N), University of Uppsala (S), Linköbing University (S)).
   •   Hydrogen Production – electrolysis (Risø National Laboratory (DK), Helsinki University
       (FIN), University of Oslo (N)).
   •   Nordic Hydrogen Energy Foresight (Risø National Laboratory (DK), Energi E2 (DK), IRD
       Fuel Cells (DK), DGC (DK), IDA (DK), VTT (FIN), Wärtsilä (FIN), Fortum (FIN), ABB
       (FIN), University of Iceland / Icelandic New Energy (IS), NTNU / SINTEF (N), Norsk Hydro
       (N), Swedish Defence Research Agency (S), Vattenfall (S), AGA (S), Swedish Hydrogen
       forum (S)).
Finland has been investing Fuel Cell and Hydrogen technologies since 1995, primarily through the
National Technology Agency (Tekes). The hydrogen strategy is to focus on distributed hydrogen
related energy systems, to network with international activities (EU, IEA, Nordic) and connect with
fuel cell activities in Finland. Major players in the field of hydrogen are:
    • VTT Processes -- hydrogen R&D activities
   •   University of Jyväskylä -- hydrogen production from biogas by fermentation
   •   University of Tampere -- NEFP project ”BioHydrogen”
   •   HUT -- metal hydrides and hydrogen production
Finish institutions participate in the previously mentioned Nordic Hydrogen Energy Foresight and
BioHydrogen projects.

Work on production, storage and transportation of hydrogen as an energy vector was carried out in
France in 1975-1980 by the DGRST under Energy R&D European program. Hydrogen production
via high temperature processes was studied by various actors thanks to the relation of France with

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nuclear energy technologies. In 1998, the Association Française de l’Hydrogène (AFH2) was
founded, bringing together all French players in this field. The Hydrogen R&D activity started again
in 2001 after CEA decided to support the development of high temperature gas cooled nuclear
reactors, which cover a wide variety of high temperature applications. Concurrently, the CNRS
launched the program “Energy” with different themes on hydrogen. A number of players are active in
the field of fuel cells, including the French car industry. The main research bodies involved are: the
CEA, the CNRS, the INERIS, Universities, the INRETS, the CNRT and a few engineering schools
(Ecole des Mines, CNAM).

Some of the key areas of R&D in relation to hydrogen production are:
   • High temperature processes: the CEA, CNRS and industrial companies such as EDF and
      Framatome are carrying out a R&D programs on massive Hydrogen production using
      innovative High Temperature processes. This is related to nuclear reactors but solutions could
      find uses in concentrated solar technologies.
   • Low or room temperature processes: R&D on Photobiological processes is carried out in CEA
      and CNRS in cooperation with European programs related to artificial and natural
   • Small reformers: R&D areas include compact and low cost reformers (1-5 kW) to convert
      fossil fuels (natural gas, gasoline) or biomass fuels (ethanol) to hydrogen via different
      processes (steam reforming, partial oxidation, auto-thermal, non catalytic hybrid steam
      reforming), improvements in reformer efficiency, capacities and response times, integration
      of purification units

Germany has been at the forefront of hydrogen and fuel cell technology development and
implementation worldwide. Germany has various federally and regionally funded initiatives in place.
There has been strong cooperation between public and private enterprises, with involvement of the
German car industry (NEBUS, CUTE, Munich airport projects).

Intense R&D on hydrogen technologies took place between 1988 and 1995 and concentrated on the
development of specific technologies (production from electrolysis and storage) as well as on larger
projects to demonstrate the work supply chain (HYSOLAR, SWB, BAYSOLAR projects,
installations at Stralsund Technical University – please refer to Chapter 6 of this study). Following
this work, there are currently no projects being funded specifically for hydrogen and efforts have
concentrated on fuel cell technology.

No specific national plan on hydrogen and fuel cells exists in Greece, the topics have recently been
included in the Greek national research agenda while the hybridizing of wind parks with hydrogen
technologies is foreseen in commercial projects. Past research activities in Greece on these two topics
have been funded primarily by EC funds.

In the field of hydrogen production from renewables, Greek company HELBIO is developing and
marketing reformers for producing hydrogen from bio-ethanol, bio-gas or bio-oil. The Centre for

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Renewable Energy sources has developed a wind-hydrogen installation at its wind park in Lavrion, in
collaboration with C. ROKAS SA and FIT (Cyprus) in the context of the RES2H2 EC funded
project. The production of hydrogen through solar water splitting using concentrated solar collectors
and catalytic monolith reactors is being investigated by CERTH/CPERI.

The Greek research community is considering islands that are not connected to the main land as
potentially favourable sites for the earlier introduction of hydrogen energy technologies, due to the
currently high energy costs. To that end, a national effort is being undertaken for the creation of a
Greek Hydrogen island, that could be funded by frameworks like HYCOM.

Italy is another important player in the H2 and FCs scene, with R&D activities in the field starting in
the 80’s where they concentrated on the development of fuel cell technologies, with a moderate R&D
commitment addressed towards the production of hydrogen as a sustainable energy carrier. In the
beginning of ‘90s, projects were carried out for the production of hydrogen from renewable energy
sources and its utilization in internal combustion engines (ICE). Italy’s ENEA laboratories have
developed an integrated plant for the production of hydrogen from photovoltaics, while its storage
and utilisation in fuel cell has been built and tested, under the auspices of EU frameworks.

In more recent years, industrial involvement has increased in the development of hydrogen vehicles,
under the auspices of either national or international programs. In February 2001, Fiat introduced its
first prototype of a fuel cell car, the “Seicento Elettra H2 Fuel Cell” and a more advanced prototype
of the same car was presented in 2003. Both Fiat prototypes use compressed hydrogen as fuel and
fuel cell stack supplied by Nuvera.

A national R&D Program on “Hydrogen and Fuel Cells” -- supported by the Ministry of Research
and University and Ministry of the Environment -- was outlined in the framework of the National
Research Plan (PNR). Furthermore in March 2003, the Ministry of Research launched a call for
proposal on “New systems for energy production and management”. Italy is active in international
cooperative agreements, and is at the forefront of many EC fuel cell and hydrogen initiatives.

R&D activities related to hydrogen production from renewables include:
  • Hydrogen production through thermal solar (process with metal oxides/redox process)- Long
  • Hydrogen production through thermal solar (iodine-sulphur and UT-3 processes for water
     dissociation) - Transition phase
  • Innovative method for hydrogen production from biological processes (university of Padova)
  • Producing clean hydrogen from bioethanol through the development of a bioethanol reformer

The Dutch hydrogen energy activities started in the seventies, but due to the discovery of natural gas,
R&D on hydrogen energy decreased significantly. As of 1985 the Dutch National fuel cells program
focused on efficient and clean use of natural gas and coal-gas. Hydrogen production and conversion
has been part of those activities, that continued under the NECST program (New Energy Conversion

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Systems and Technologies). Separately, the Dutch energy industry is actively involved in different
aspects (e.g., as transportation fuel and transition ways from a natural gas to hydrogen energy

In 2003, the “Hydrogen Networking” program started which aims to stimulate National and
International co-operation and programmatic tuning. In addition the public-private funded
“Sustainable Hydrogen” program has been initiated. Its objective is to stimulate hydrogen research
activities at universities. Hydrogen production from renewables includes:
    • Many biological projects run in the Biohydrogen Platform (National co-operative platform
        involving 11 Dutch institutes, universities)
    • Various thermal and hydrothermal processes (BTG, TNO, ECN and institutes)

Hydrogen and fuel cells activities in Norway have mostly been parts of larger R&D-programs within
the field of renewable sources of energy. The main effort during the last 5-10 years has been related
to more or less fundamental and basic R&D. The basic research has mostly been related to material
science with potential application, especially within membranes for fuel cells, catalysts for PEM-fuel
cells, electrolysers, and materials for hydrogen storages (mostly metal hydrides).

A recent Norwegian government paper on energy and environment noted that hydrogen will be
important and will play a vital role because of its advantages when it comes to environmental
impacts. The Norwegian Parliament has also established a national Hydrogen Committee to define
national targets to develop hydrogen as energy carrier, identify means and instruments for added
value and better environment, identify necessary participation from government and framework
conditions, and propose organization, responsibility and necessary funding for a national hydrogen

Norway has realised the “Utsira” project on the island of Utsira for the production of hydrogen from
wind energy and its subsequent use in fuel cells for re-electrification. The project was initiated by the
company Norsk Hydro, whose activities include the development of electrolysers as well as the more
general creation of Hydrogen communities (chapter 6.1). IFE is a research establishment in Norway
also investigating hydrogen energy systems that include renewables (HYDROGEMS software tool)
and hydrogen storage technologies.

Spain initiated activities in hydrogen and fuel cells research in the early 1990s, and continues to focus
its work in the areas of hydrogen productions (particularly from photovoltaic powered electrolysis),
hydrogen storage (tested in compressed gas cylinders and metal hydrides), the development of
materials for MCFC and PEMFC, fuel cell design (validation of 2.5 kW PEMFC), and fuel cell
testing (stacks and components). At present there is not a specific program devoted to hydrogen
energy and fuel cells in Spain, however, the Spanish Plan for Scientific Research, Technological
Development and Innovation (2004-2007) in the energy area, will consider these topics as separate
items included in the priority devoted to renewable energies and emerging technologies.

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The level of involvement of Spanish car industries is increasing, as well as other industries including
industrial gas, utilities and renewables players. Up to the present, the Spanish industries have taken
part as partners in hydrogen and fuel cell European projects with increasing emphasis as Spanish
Research Centres and the private sector are coordinating some major European projects.

With respect to hydrogen production from renewables, the production of electrolytic hydrogen using
renewable energy is being investigated (PV and wind), as well as photoelectrolysis, photobiology or
biomimetic processes. Some of the EU projects related to RES-hydrogen that are co-ordinated by
Spanish partners are:
    • FIRST – FC Innovative Remote system for Telecom utilising Photovoltaics to drive an
       electrolyser (co-ordinated by INTA)
    • RES2H2 – Hydrogen production from wind energy, involving two sites, one in the Canary
       islands and another in Greece (lead by Inabensa and then ULPGC)

There is no national program or strategy for hydrogen related activities existing in Sweden,
nevertheless, the Swedish National Energy Agency has identified hydrogen and fuel cells as one of
the strategically important areas and is actively involved in funding fuel cell and hydrogen-related
projects. The only large-scale program is related to artificial photosynthesis, performed by a
consortium between several Swedish Universities.

Under this consortium, the university of Uppsala, (photo biological hydrogen production and
photoelectrochemical production of hydrogen) and KTH (storage of hydrogen) cooperate to develop
an educational exchange between students at the different faculties. Since 2003, this program
includes photo biological hydrogen production from cyano bacteria.
Hydrogen is considered as one of the most important future secondary energy carrier in the Swiss
National Energy Research and Development Programme. Consequently, the Swiss authorities
continue to support activities for the sustainable production, safe storage and efficient use of
hydrogen, including fuel cells.

Research and development of hydrogen energy and technology are co-ordinated and financially
supported by the Swiss Federal Office of Energy. Federal and cantonal research institutes as well as
private institutions and industries guarantee additional financial support. The Swiss Hydrogen
Competence Centre, Hydropole exists since autumn 2000. This centre surveys ongoing pilot and
demonstration projects, and documents and promotes new alliances among institutional and industrial
partners. All activities are closely co-ordinated with the IEA and EU research programs.

In terms of hydrogen production, topics investigated include high pressure electrolysis of water using
Switzerland’s extensive hydropower, thermo-chemical splitting of water using a high temperature
metal/metal oxide redox cycle driven by concentrated solar radiation, and room-temperature
generation of hydrogen by the photo-catalysed splitting of water using solar radiation via the so-
called tandem-cell. Hydrogen production from bio-mass has also been studied.

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Hydrogen research is carried out in different institutions: solar driven hydrogen production is under
investigation at the Paul-Scherrer-Institute, while photocatalytic splitting of water is the focus of
work by an alliance of the Universities of Bern and Geneva and the Federal Institute of Technology

Turkey has engaged in limited work on hydrogen in fuel cells. Most of the effort is driven by the
TUBITAK Marmara Research Centre (TUBITAK-MRC), involving selected hydrogen related
projects and fuel cell development. Work on hydrogen is currently oriented toward utilisation in
transport and stationary applications on both civil and military levels. A policy study have been
undertaken on an Energy production plant based on new, renewable and national energy sources. It is
aimed that Turkey will be among the first nations to manufacture a hydrogen vehicle. No major effort
exists at the moment for hydrogen production from renewables.

The involvement of the UK in the field of hydrogen and fuel cells is mostly in the field of fuel cells,
utilising the research base that is active in the fields of materials science, catalysis and bio-
engineering. The DTI has been supporting industrial research on fuel cells since 1992 under its
Advanced Fuel Cell Programme. During its lifetime the focus of the program has changed from
supporting studies designed to inform the DTI and the industry regarding the prospects for fuel cells
to work to supporting the development of UK capabilities. The Energy White Paper *February 2003)
sets out a strategy for the long term, and to give industry the confidence to invest in a truly
sustainable energy future. The paper, among other issues, sets the goal that hydrogen will ultimately
be generated primarily by non-carbon electricity. In the long term part of this vision report (2013-
2023) it is foreseen that renewables will play an ever increasing role in the production of hydrogen.

With respect to hydrogen from renewables, the planned Tees Valley Hydrogen project will address
hydrogen fuelling and hydrogen production from renewable sources. On the Unst island (Shetlands) a
wind-hydrogen installation has been established in the context of the PURE project.

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Renewables are expected to be an important source for the energy required for the production of
hydrogen in the future. Even though hydrogen production and renewable energy technologies are
well advanced, their integration is an area of current research. Additionally there are other pathways
that are only now being investigated and for which there exists considerable R&D potential.

The areas where future R&D efforts should be concentrated in the field of hydrogen production from
renewables have been investigated in a number of studies, performed by:
       the IEA, in the context of the Hydrogen Co-ordination Group activities [IEA, HCG]
       the IEA, in the context of the Hydrogen Implementing Agreement [IEA, H2PROD, 2005]
       the Department of Energy, Argonne National Laboratory [DOE, 2004]
       the European Hydrogen and Fuel Cells Platform, in the context of the Strategic Research
       Agenda [SRA]
       the DGs TREN and RTD of the European Commission have recently awarded a contract for
       an Integrated Project titled Roads2HyCOM that will enable the creation of the first hydrogen
       communities in Europe, with a task to identify areas of further research

Reference is made below to the areas identified in the previous studies where further research is
required with respect to technological improvements. In terms of the time scales involved, it is
foreseen that in the short-term (2005-2015), water electrolysis and small-scale natural gas reformers
will be used for hydrogen production while in the medium-term (2015-2030), it is foreseen that
centralised hydrogen production will be based on fossil fuels with capture and storage of CO2. In the
long term however (2030+) the hydrogen economy will depend increasingly on electrolysis from
renewables and nuclear, provided additional R&D is undertaken on various issues including:
    • The production of hydrogen from biomass; considering larger scale and improvements on the
        preparation and logistics of the feed
    • Photo-electrolysis is at an early stage of development and material cost and practical issues
        will need to be addressed
    • The photo-biological processes are at a very early stage of the development with only low
        conversion efficiencies obtained so far
    • High temperature processes need further materials development, focusing on high
        temperature membranes and heat exchangers.

More specifically, R&D efforts for the production of hydrogen from the splitting of water should
concentrate on:
   • Alkaline electrolysers: design and manufacturing of electrolyser equipment at lower costs
       with higher energy efficiency and large turn down ratios. The future hydrogen costs from
       electrolysers is presented below:

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       Fig. 22 future potential for cost of electrolystic hydrogen [IEA, H2PROD, 2005]

•   PEM electrolysers: not as mature as alkaline electrolysers with relatively high cost, low
    capacity, poor efficiency and short life time. Their performance has the potential to be
    improved through material development and cell stack design
•   High temperature electrolysers; need for materials development and improved thermo-
    mechanical stress within the functional ceramic materials, similar to the main challenges for
    the SOFC.
•   Photo-electrolysis: this is a technique at an early stage of development and thus there is
    plenty of scope for improvement through R&D related to progress in material science and
    engineering. The development of highly efficient, corrosion-resistant photo-electrode
    materials and their processing technologies are important, paving the path toward smart
    system integration as well as engineering. Since no “ideal” photo-electrode material for water
    splitting exists commercially, tailored materials have to be engineered. Corrosion and photo-
    corrosion resistance concern further significant R&D challenges to be addressed with most of
    the promising material options at hand. Both current-matching between anode and cathode
    and ohmic resistance minimisation require considerable systems design as well as
    sophisticated engineering solutions. Optimisation of fluid dynamics (mass and energy
    transfer) and gas collection and handling (operational safety) will demand major conceptual
    and application specific R&D attention.
•   Bio-photolysis: R&D is needed in the field of photo-biological production (photosynthesis
    and H2 production from hydrogenases) to understand the natural processes and the genetic
    regulations of H2 production. Improved cells need to be constructed by metabolic and genetic
    engineering and demonstrate the process in larger bioreactors. Another option is to reproduce
    the two steps using artificial photosynthesis
•   Thermolysis: Thermolysis or high temperature decomposition has the potential to allow bulk
    production of hydrogen at low costs. TO achieve this, the technical challengens that must be
    addressed are materials developments due to the need for corrosion resistance at high
    temperatures, high temperature membrane and separation processes, heat exchangers, and
    heat storage medium development.

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Gasification and pyrolysis is considered the most promising medium term technology for the
production of hydrogen from biomass. Since biomass comes in varied form and quality depending on
climatic conditions, crop and collection and handling method, developments must be realised also
upstream of the gasifier. Thus areas of further R&D include:
    • Feed preparation - Identify the characteristics of feedstocks that will allow the technologies to
    • Gasification of biomass. This is not specific for hydrogen; but is followed-up in relation to
        general biomass and renewables pathways and research
    • Raw gas handling and clean-up
    • Interface issues and system integration. One should also investigate on the relationship
    • production scale and fuel quality requirements and tolerances that can be accommodated for
        the respective technologies

With respect to hydrogen production though the conversion of biofuels (e.g. ethanol, bio-oil) to
hydrogen through reforming, research priorities include:
   • development of improved catalysts that rely less and less on noble metals
   • development of catalysts that would support a lower-temperature, water-gas shift reaction,
       and improved catalysts for desulphurisation of feedstocks
   • development of catalysts that are more active, more specific, more stable, and less susceptible
       to poisoning and fouling
   • development of semi-permeable membranes for the separation and purification of gas streams
       through improvements in membrane selectivity and robustness at elevated temperatures (200–

Lastly, some cross-cutting areas for further research include:
   • materials development for electron and ion transfer at catalyst/electrolyte interfaces
        encountered in solar PV photo-electrochemical and bio-mimetic hydrogen production present
        problems similar to PEM fuel cells
   • high temperature resistant materials are required for thermally assisted electrolysis, similar to
        that of solid oxide fuel cells

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Hydrogen along with electricity are claimed to be the energy vectors of the future, readily changing
from one form to the other, or joining eventually into a single entity referred to as “hydricity”. Given
that fossil fuels are finite while their use is detrimental to the environment, hydrogen seems a
favourable energy vector to replace liquid and gaseous fuels in transport or stationary applications,
along with other alternative fuels.

The production of RES-derived hydrogen can be dispersed or centralised, the optimum choice being
site specific. It is expected that hydrogen technologies will be first applied in niche applications and
markets that would include:
         back-up units for telecom relay stations (few kWs of power)
         UPS for applications requiring 100% power availability like computer centres or hospitals
         (few 10s of kWs of power)
         power generation for remote stand-alone applications (few 100s of kWs of power)
         storage of excess energy from renewable energy installations operating on weak electricity
         networks (few MWs of power)

There are few studies that have studied the market potential of RES-hydrogen applications at
different scales. The market potential of RES-hydrogen technologies in stand-alone power systems
(up to 300kW) has been investigated in an Altener study titled “Market Potential Analysis for
Introduction of Hydrogen Energy Technology in Stand-Alone Power Systems” with the acronym H-
SAPS. The market for larger wind – hydrogen applications has also been addressed [Altmann 2000,
Dutton 2004]

9.1. SWOT analysis of RES-Hydrogen stand alone systems (up to 300 kW)
The methodology used in the H-SAPS Altener study was to perform a Strengths-Weaknesses-
Opportunities-Threats (SWOT) analysis and then considering technological push, market pull and
environmental issues in order to assess the market potential of RES-hydrogen systems. The
HYDROGEMS software library was used to simulate existing stand-alone systems and calculate
variants of these systems that incorporate optimised hydrogen production, storage and use

The SWOT analysis was done in order to identify the most obvious success factors. Strengths and
Weaknesses refer to the product itself (hydrogen technologies in stand-alone systems) and constitute
so-called internal factors, which may be influenced. Opportunities and Threats refer to the external
environment affecting market development of the product. The table below shows the SWOT
analysis covering technological, market and environmental aspects of RES-hydrogen based stand
alone systems.

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Strengths                                                   Weaknesses
       Existing experience in handling compressed gases           Technology immaturity of fuel cells and PEM
       High noise level of the main competing systems             electrolysers
       (e.g. Diesel Engine Generators Sets)                       Low availability and high cost of small
       Seasonal energy storage without energy loss over           electrolysers
       time                                                       Lack of component and system life-time
       Able to handle power fluctuations and therefore            experience
       ideal for integration with intermittent renewable          Low component efficiency
       energy sources                                             Missing codes and standards
       Renewables       can     become     “dispatchable”         Lack of after sales support
       (guaranteed power from renewables)                         Weak supply network (providers, installers, etc)
       Self-sufficient energy supply system                       Lack of public awareness
       Potential for low and predictable O&M costs                Lack of recycling and re-use schemes for
       Avoidance of fuel transport costs                          hydrogen technology
       Reduced environmental impact compared to
       conventional energy systems
Opportunities                                               Threats
       Emergence of large scale markets for hydrogen              Limited practical experience due to few true
       energy applications                                        Stand-Alone Power Systems with hydrogen as an
       Already existing Stand-Alone Power Systems                 energy carrier (H-SAPS) installed
       driven by Renewable Energy Sources in which                Competing technologies have proved to be
       hydrogen technologies can be incorporated as a             perfectly adequate
       replacement of batteries                                   Potential end users have no experience in H2
       New job opportunities                                      technologies
       Diversification of companies involved in the               Inadequate legislative framework (standards,
       energy sector                                              regulations, permissions of installation)
       Energy costs in conventional SAPS relatively high          Low interest and priority from utilities and major
       Reduction of environmental impact compared to              suppliers of SAPS components / systems
       conventional fossil based solution

                  Table 8 SWOT analysis RES-hydrogen based stand-alone systems

9.2. Economic viability of RES-Hydrogen stand alone systems (up to 300 kW)
Techno-economic modelling of five existing SAPS systems was performed that were chosen on the
basis of diversity in climate conditions, renewable energy technology, power demand and load
characteristics. They represent four climatically different parts of Europe, include the energy sources
PV, wind and small hydro, range from 8 – 70 kW and include both seasonal and all year load
characteristic. The five cases were:

   •   Kythnos (Greece)                           PV-Diesel-Battery
   •   Fair Isle (UK)                             Wind-Diesel
   •   Rum (UK)                                   Micro-Hydro - Diesel
   •   Rauhelleren (Norway)                       Diesel only
   •   La Rambla del Agua (Spain)                 PV - Battery

The present and future costs of the hydrogen technologies involved were assumed as per the
following table:

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Hydrogen                             Type                            2003-5                                    Long-term (2020)
                                                                      O&M            Cost                           O&M
                                                  Lifetime                                          Lifetime                        Cost
                                                                      (% of                                         (% of
                                                   (years)                                           (years)
                                                                    inv.costs)                                    inv.costs)
                                                                                    8,150                                           4,075
 Electrolyser                  (30 bar outlet            20            2.0                            20             1.0
                                                                                   €/Nm3/h                                        €/Nm3/h *
  Fuel Cell                      PEM-type                10            2.5                            20             1.0       300 €/kW♣
                              Compressed gas
H2-storage unit                                          20            0.5         38 €/Nm3           20             0.5       25 €/Nm3♠
                                 (30 bar)

 Table 9 Assumed lifetime and operations and maintenance cost, and estimated specific costs for the
                    hydrogen energy system components at present and in 2020

The simulations showed that the economic viability of hydrogen solutions is strongly dependent upon
the site characteristics (local RES resource). The following figure shows the cost of energy (COE) of
all five cases at present (2003-2005) and in the long-term based on the data of the previous table.

                                        Ref.case (2003)
                                        H2 - 2003-5
                              1.60      H2 - long-term

              COE (€ / kWh)







                                        Rambla        Rauhelleren            Rum             Fair          Kythnos

  Fig. 23 Comparison of the cost of energy (COE) for the conventional SAPS and H-SAPS in 2003-
                       2005 and in the long-term for the 5 simulated cases

The technical features for the case of Kythnos summer settlement case study before and after the
application of hydrogen energy technologies are shown below:

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           Conventional SAPS - Kythnos                      H-SAPS - Kythnos
                                                         PV-modules: 139 m² (16 kW)
               PV-modules: 73 m² (8.8 kW)
                                                              Electrolyser: 18 kW
                      DEGS: 8 kW
                                                        Hydrogen storage unit: 2500 Nm³
                 Diesel tank: 3000 litres
                                                                Fuel cell: 8 kW
                    Battery: 280 kWh
                                                               Battery: 140 kWh

                  Fig. 24 Technical features of the Kythnos settlement case study

The discounted capital costs between the conventional and the H-SAPS cases are shown below, along
with a breakdown in the constituents of each cost. Operation and maintenance costs do not include
the cost of fuel.

        3%                             PV
                                       Diesel tank
                           36%         Battery                                                    500

     34%                               Inverters
                                                                    Total discounted costs (k€)

                  7%1%                                                                            350

         7% 3% 8%                      PV                                                         200
      11%                              Electrolyser
                           26%         H2-storage                                                 50
                                       Fuel Cell                                                   0

                                       Battery                                                          HSAPS    SAPS

     26%                               Inverters
                     19%               O&M

 Fig. 24 Discounted capital costs for conventional and Hydrogen stand alone systems for the case
                                         study of Kythnos

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The large variations in costs for the conventional systems are due to the different RE technologies
(electricity from PV being 2-3 times more expensive than wind), varying diesel costs (varying
transportation costs) and other site characteristics such as renewable electricity and load match. The
system modelling showed that the cost of H-SAPS is high and that the main problem is to limit the
storage demand. A direct consequence of this would be to ensure that any demonstration or test plant
is ideally configured with regards to RES and match of RES and user load.

Another important issue is the division of electrical and thermal load in order to raise the total energy
efficiency of the hydrogen energy system. In addition, it is important to recognise the need for
prioritising loads by introducing load control, which is already operating successfully in a number of
conventional SAPS. This is a powerful tool in reducing COE for the system.

Electrolyser and storage units contribute significantly to the overall system costs. Electrolyser cost
reduction is then equally important compared to the cost reductions for fuel cells for this early market
segment. At present, the hydrogen technology industry can almost exclusively recognise the near-
term potential for fuel cell power systems based on distribution of hydrogen from centrally produced
hydrogen, as the hydrogen production option from RE is too expensive. The source for distributed
hydrogen, with Air Liquide and Linde as main actors, are almost exclusively fossil (steam reforming
of natural gas).

In the H-SAPS modelling study, the two PV-based H-SAPS systems situated in southern Europe, and
the Fair Isle wind / hydrogen system, were found to be able to compete with conventional power
SAPS. The PV-based systems are situated in sunny regions and have low energy and power demand
at night. This gives a smaller energy storage demand. Energy storage is needed on a weekly, rather
than monthly or seasonal basis. The prospects for Fair Isle system also appear favourable in the long-
term. This is mainly due to extremely good wind resources and a system, which even today seems to
be slightly over-dimensioned.

9.3. Market Assessment of RES-Hydrogen stand alone systems (up to 300 kW)
The market assessment is divided into three parts covering the demand side, the supply side and the
external factors that affect both the demand and supply sides.

In order to assess the demand side, possible users were grouped into three groups:
    • High cost grid connected users
    • Conventional SAPS users
    • Users with no access to electricity

The last two categories were identified as the most promising ones, while for the first category (grid
connected users) there could be a small market in case the grid connection is too expensive to
maintain and operate for the grid owner or if the customer is not satisfied with the quality of the
electricity supplied through the grid. The main competitors to RES-hydrogen based stand alone
systems are diesel gen-sets and grid extensions. The principal market barrier in this segment is high
upfront costs, which still deter potential users, along with the fact that the end-user does not possess
knowledge of the available technology.

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Such users / applications could be:
   • Residential electricity supply
   • Agricultural activities
   • Tourism
   • Water treatment and desalination
   • Back-up power systems
   • Communication
   • Others (lighthouses, food processing, etc)

The estimated market potential for hydrogen based stand alone systems in Europe is shown in the
following table [Zoulias 2004, Merten 1998]
                                                                                 Total annual
                                   Number of           Unit         Total          energy
                                    dwellings        power          power          demand
                                 (users) covered      (kW)          (MW)           (GWh)
Rural villages, settlements
                                      500 000             3          1 500           1 601
and rural housing
Back-up power systems                   2 000             5            10               7
Rural tourism
                                       10 000             5            50              37
Rural tourism
establishments with strong              1 500            30            45              30
energy requirements
Rural farming and
                                         200             40             8               4
Water desalination plants
                                         550              4             2               4
Waste water treatment                    450             10             5              10
Large communication
                                         150             10             2              13
TOTAL                                                                1 621           1 706
         Table 10 Summary of the estimated future potential market for H-SAPS in Europe

The supply side can be divided into two main groups:
   • the operational market players
   • the visionary market drivers

In the short-term (5-10 years) related technology is not expected to reach a maturity level so as to
offer economically viable solutions. It will thus be mostly visionary market drivers who at the same
time are well-established players in the energy scene who will be involved in the first niche
applications, like Shell, BP, Hydro and others. The national governments will have a key role to play
to support those visionaries and trigger the hydrogen market.

The possible steps up to reaching the viable market are presented in the following figure:

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                   A = Portable applications         E                E
                   B = HSAPS
                   C = Grid islanding                         Main future market
                                                                Mobile applications
                   D = Large Wind/H2 systems
                   E = Residential units


           Figure 25 Presentation of the route to market for hydrogen energy applications

In figure 25 it can be observed that a number of the niche and initial markets for hydrogen energy
applications are related to RES technologies, including stand-alone systems, grid-islanding and large
wind-H2 systems.

Lastly the external factors affecting the market development of small scale RES-hydrogen stand
alone systems are:

Energy policy factors:
      • General political climate for RES
      • Energy mix for RES (security of supply, diversification, environment)
      • Subsidies and Fiscal measures for RES (tax incentives, certificate trading, etc.)
      • Implementation of the RES electricity directive

Other factors:
       • Cost of fossil fuels
       • Security and quality of supply (blackouts, natural disasters, terrorist attacks)
       • Population and Public perception
       • Formal procedures in local planning (environmental regulations, local planning)
       • Internalisation of externalities of environmental pollution

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9.4. Market Assessment of wind-hydrogen systems (up to 5 MW)
The market potential of systems that use hydrogen as means to store excess energy so as to be able to
cover electricity demand during periods of low or zero wind energy production has been investigated
in the WHySE project [Altmann, 2000]. The study compared wind-hydrogen systems with diesel
systems, determining the market potential of 1kW to 5 MW wind-hydrogen systems on European

Systems were divided into four categories according to size, micro (1 kW), small (10kW), medium
(100 kW) and large (5 MW). Rough sizing was preformed since detailed sizing would depend on the
specificities of each site, however identical systems were chosen for small power installations (large
numbers would reduce costs) while for larger power installations each system would need to be
optimised to local conditions. The cost breakdown per kW installed for the four categories studies is
shown in the following figure. It should be noted that these are targets rather than prices that were set
in 2000 for year 2005, that would have been reached if industrial action was taken immediately.
Prices today are rather different, considering costs of wind turbines with that of electrolysers and
especially the cost of fuel cells, for which large reductions were expected, however one could assume
that this type of breakdown could be achieved if significant industrial development was undertaken in
the short term.

 Fig. 26 Targeted investment cost of wind-hydrogen systems for year 2005 (1 Euro is approx. 2 DM)

The analysis showed that RES based systems like the wind-hydrogen systems examined would
replace the variable (fuel) costs of a conventional diesel system by capital costs, the economic
viability of wind-hydrogen systems being dependent on the price of diesel fuel.

The electricity costs as a function of system size were estimated as depicted in the following figure. It
should be noted that operation and maintenance costs were assumed to be equal to 40% of total
electricity costs for small systems, reducing to 10% for the large systems. The analysis showed that
large systems have a chance to compete with diesel based systems. However one should make note of
the cost assumed for electrolysers (Fig. 26) which is less than an order of magnitude of the actual cost
of these units following a market survey (Fig. 31). It should also be noted that the cost breakdown of
the Kythnos PV-Hydrogen system of the previously described H-SAPS project (Fig. 24) is
considerably different to the one of this study.

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The study concluded that in order to achieve the cost figures estimated for wind – hydrogen systems,
industrial groups should be formed between manufacturers of the major components of such systems
(wind turbine, electrolyser, fuel cells, storage, control) in order to develop the overall system concept
and then build each component according to the requirements of the overall system.

    Fig. 27 Electricity costs of wind-hydrogen systems compared to costs of diesel generator sets
                                       (1 Euro is approx. 2 DM)

9.5. Country-wide studies for wind-hydrogen technologies
The commercial potential of energetic hydrogen installations has been investigated by researchers for
a number of countries including Ireland [Gonzalez, 2003], the UK [Dutton, 2004] and the state of
California [Lipman, 2005]

For the case of the UK, hydrogen is considered to have the potential to contribute in the reduction of
greenhouse gas emissions from the transport sector. Indeed, a series of scenarios were examined at
the Tyndall Centre for Climate Change Research exploring possible transition pathways against a
background of different socio-economic landscapes. The scenarios indicated the major potential role
for wind energy in reducing carbon dioxide emissions in the electricity supply system. It became also
apparent that the UK Government’s target of 60% reduction of emissions by 2050 will be hard to
meet while sustaining current standards of living without significant progress towards replacing
petroleum as a transport fuel.

The four different scenarios examined were related to “values” and “governance”. Technology is
considered not as autonomous but as emerging from a combination of the dominant values and the
governance system. The scenarios were tiled:
   1. World Markets
   2. Global Sustainability
   3. Provincial Enterprise
   4. Local Stewardship

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The THESIS software tool was used that predicts the potential carbon dioxide savings at any
timescale into the future arising from different strategies of implementing a hydrogen energy
economy. The demands in electricity and fuel from the Transport, Domestic, Industry and Services
sectors were the major input to the model, aiming to study the effects of introducing hydrogen
produced from wind energy in CO2 emissions. For each scenario, the potential uptake of hydrogen
and the most likely production technologies were estimated.

The World Markets scenario showed the lowest level of hydrogen demand, insufficient to promote
technology development. By 2050 hydrogen production is predominantly from SMR (small/medium
plants) with conventional storage technologies. Some electrolysis was to be used for small levels of
production in niche areas (but electricity was drawn from the bulk supply and was not generated from
specific low carbon sources).

The Provincial Enterprise scenario was characterised by the preferential use of indigenous fuels. The
gasification of coal proved prominent for the UK as a major hydrogen production technology, with
hydrogen replacing imported fuels.

The Global Sustainability scenario displayed high penetrations of hydrogen (particularly in the
Transport sector) and strong environmental protection measures driving the expansion of low carbon
hydrogen sources. Coal was used with sequestration. Rapid development of hydrogen technologies
lead to the realisation of solid-state storage modules for vehicles by 2025. Considerable additional
electric plant capacity is estimated to be required to support the required level of hydrogen
production. A marked increase of 65,000 MW of nuclear capacity and over 210,000 MW (nameplate
capacity) of renewables was determined by the THESIS model.

In the Local Stewardship scenario the demand for energy services was the lowest and was the only
scenario in which the overall energy demand actually decreased in all sectors. The electricity mix by
2050 was largely renewables-driven, supported by a declining contribution from natural gas. Local
energy sources (renewables and to a lesser extent coal) were selected for hydrogen production.

CO2 emissions for the four scenario were estimated and are shown in the following picture. Under the
World Markets and Provincial Enterprise scenaria, where economic and market considerations
predominate over environmental concerns, the work suggested that UK carbon dioxide emissions
would increase. Maximum reductions were obtained under the Global Sustainability scenario, which
showed that for the vision of a hydrogen energy future based on renewable electricity to materialise,
this would require a very large and sustained investment in renewable electricity generating capacity,
a large proportion of which can be expected to be based on wind energy (capacity factor 0.25 for on-
shore and 0.35 for off-shore). Hydrogen is produced chiefly by electrolysis from the capacities of
RES and nuclear mentioned previously. Lastly it was concluded that while hydrogen introduction
into the transport sector may be driven by automobile manufacturers, the benefits of reduced carbon
dioxide emissions are unlikely be realised without appropriate political backing for low-carbon
hydrogen production routes.

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           Fig. 28 The scenarios landscape used by the THESIS software [Dutton, 2004]

Hydrogen production as a way to harness the considerable wind resource of Ireland has been
investigated by researchers [Gonzalez, 2003]. Ireland is the second most energy import-dependent
country in Europe (87% of the energy needs in 2001). At the same time, it is estimated that
greenhouse gas emissions will rise by 37% in the period 1990–2010, whereas Ireland is committed to
a maximum increase of 13% according to the Kyoto protocol. The exploitation of RES is thus a
necessity for Ireland. However, increasing the installed capacity of wind energy for example results
to changes in system management to ensure power reliability and quality and to maintain the
necessary reserve capacity, and usually demands costly grid reinforcements.

The introduction of new technologies and strategies, such as forecasting, geographical dispersion,
interconnections, and sophisticated power electronics, will mitigate these problems to some extent,
but, as these do not remove the fluctuating nature of wind, the large penetration of wind will
ultimately require the uptake of energy storage. Hydrogen is considered an attractive option due to its
multi – functionality, since it can be converted back to electricity or used as a clean fuel in transport
(fig. 29), which is considered the main driver for the introduction of hydrogen as an energy carrier.

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                              Fig. 29 Wind – hydrogen system concept

The feasible wind energy resource in Ireland is estimated at 344 TWh/y (125 GW capacity), or ten
times more than the future electricity demand of 33.5 TWh predicted for 2010, which resource is
however curtailed by spatial planning. Hydrogen is examined as a way to increase the penetration of
wind energy that would be limited by the capacity of the electrical transmission network or the limit
set by the electricity company. Also it is investigated as a way to increase the controllability
(dispatchability) and low capacity factor of wind power. To estimate the benefit of increasing wind
energy penetration three types of “value” are considered:
    1. energy value, reflecting the avoided costs of generating electricity by other sources
    2. generation capacity value, reflecting the generation costs that wind capacity can avoid by
        allowing the shutdown and decommissioning of conventional plants
    3. transmission and distribution value, representing the benefits of embedded generation –
        avoidance of building new lines

According to most authors, the value of wind energy does not vary significantly at penetration levels
up to 10% (on an energy basis), but a marked decrease occurs beyond 20% due to the need of grid
reinforcement. The generation of hydrogen from excess wind-generated electricity offsets the drop of
wind energy value at high penetration levels in the following ways:
        the smoothing of power reduces the need for ancillary services to maintain power quality.
        avoiding the shutting down of wind parks
        reducing the scale of grid reinforcements if hydrogen plants are near the wind parks
        providing a clean fuel for urban transport

The economic viability of wind-hydrogen systems is expected to be affected by:
       energy market failures in case the tariff system or electricity trading arrangement used is not
       high cost of components, specially of the electrolyser, caused partly due to the lack of
       competitiveness in a market occupied by only a handful of manufacturers throughout the

An analysis of a hypothetical 100MW wind park located in Ireland has shown the following results in
terms of the electrolysis plant installed capacity in MW, in terms of the value of surplus electricity
and the value of hydrogen as a fuel or commodity:

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    Table 11 Optimum electrolysis plant size in MW for a 100 MW wind park [Gonzalez, 2003]

The State of California in the US has assigned the University of California, Berkley, to compare
various energy storage technologies that can potentially enhance the operation of wind power and
other intermittent renewable energy systems [Libman, 2005]. Economic and environmental analyses
of four energy storage options were conducted, namely:
    • lead acid batteries
    • zinc bromine or flow batteries
    • hydrogen production, storage and re-conversion to electricity
    • hydrogen production, storage and sale for fuelling hydrogen-powered vehicles

These technological options for storing excess win energy were considered under two wind
penetration scenarios (10% for 2010 and 20% for 2020) at four California sites that are likely to
experience significant wind farm development. The HOMER simulation tool of NREL was used for
the simulations, however real scale wind –hydrogen installations are being installed in California for
testing the technological aspects of such systems, as in the case of a wind park near Palm Springs
(Fig. 30)

    Fig. 30 An electrolyser being installed at a wind park near Palm Springs in California, USA
                                           [Libman, 2005]

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Some of the results of the simulations for the 2010 and 2020 scenaria amounting to 10% and 20%
wind penetration are shown in the following tables.

    Wind park /                Altamond              San Gorgonio           Solano          Tehachapi
Electrolyser – fuel                        N/A                      2,277            N/A           3,075
cell (SSB)
Electrolyser – fuel                        N/A                      2,134            N/A           2,616
cell (FB)
Solid         State                   241,056                       2,298      463,594             3,033
Flow Battery*2                        121,723                       1,728      241,318             2,151
   SSB= system sized to match solid-state battery system output
   FB= system sized to match flow battery system output

                      Table 12 Annual cost of stored energy in $/MWh for 2010 scenario

    Wind park /                Altamond              San Gorgonio           Solano          Tehachapi
Electrolyser – fuel                     59,241                       476       758,167                  411
cell (SSB)
Electrolyser – fuel                     32,158                       927       368,238                  905
cell (FB)
Solid         State                     33,250                       829       247,250                  846
Flow Battery*2                          17,523                       783       127,042                  788
     SSB= system sized to match solid-state battery system output
     FB= system sized to match flow battery system output

                      Table 13 Annual cost of stored energy in $/MWh for 2020 scenario

The key findings of the study were that:

      •    All energy storage systems were better utilised for the case of high wind energy penetration
           (20%) assumed for 2020 where 1600 hours of operation per year were estimated, compared to
           the low penetration of 10% assumed for 2010
      •    At low levels of wind penetration (1%–2%), the electrolyser /fuel cell system was either
           inoperable or uneconomical

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•   In the 2010 scenarios, the flow battery system delivered the lowest cost per energy stored and
•   At higher levels of wind penetration, the hydrogen storage systems became more economical
    such that with the wind penetration levels in 2020 the hydrogen systems delivered the least
    costly energy storage
•   However, the hydrogen production scenario (compared to energy storage through re-
    electrification) delivered the greatest financial revenue
•   A general conclusion was that energy storage systems have relatively limited application
    potential at present but may become of greater interest over the next several years, in areas
    that are experiencing significant growth in wind power and other intermittent renewables.

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The increasing demands for abundant energy sources on one hand and environmental protection on
the other have promoted hydrogen high on the research agenda as a potential major energy carrier
along with electricity. The Hydrogen economy seems as a possible long-term solution for a secure
and sustainable energy future.

The gap between today’s capabilities for the production, storage and energetic use of hydrogen and
those required to reach the “Hydrogen economy” is enormous. Significant gains must be achieved in
the efficiency and reliability of various components along the chain, while the costs for producing
hydrogen must be lower by a factor of 4, while that of fuel cells by a factor of 10. To achieve these
ambitious targets major R&D efforts need to be undertaken and indeed appropriate funds are being
funnelled in this field at various levels.

The production of hydrogen in a CO2 neutral way is one of the key elements for reaching the
sustainability targets of the Hydrogen economy. This can be obtained through the integration of
hydrogen production technologies with renewable energy sources and the respective technologies.
The vision of an energy stream originating from the sun and flowing through hydrogen to perform
electrical or mechanical work, producing only water as its by-product is the essence of the Hydrogen
economy. The biological world has established its own hydrogen economy three billion years ago,
using solar energy, hydrogen, oxygen and carbon in the photosynthesis cycle. The human hydrogen
economy can similarly exploit the flexibility of hydrogen to link with various renewable energy
sources and a multitude of energy uses.

A review of the various methods for the production of hydrogen from renewable energy sources has
been presented in the present study, covering both established methods like electrolysis and
reforming, but also methods that are still in the early development phase like thermolysis or bio-
photolysis. A list of areas requiring further research in order to improve efficiencies and reduce costs
has been presented, covering the technologies per se but also cross cutting issues.

Besides the technical challenges, the economic viability of hydrogen as an energy carrier must be
proven, including RES-hydrogen systems. Indeed there are cases where RES-hydrogen technologies
can become economically viable once cost targets are met, like in the case of small autonomous
systems or large systems enabling high penetration of renewables in the electricity network though
the storage of excess electricity in the form of hydrogen, as was presented in the present study.

Europe has been the leader in technologies like electrolysers and reformers and similarly in
technologies related to renewables. It is important that Europe builds on this expertise in order to
establish its role and market in the global market of integrated renewable and hydrogen technologies
systems through concerted efforts to this end.

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Altmann M., Gamallo F.
Autarke Wind-Wasserstoff-Systeme
Downloadable from http://www.hyweb.de/Wissen/autarke.htm

Altamnn M. Niebauer P., Pschorr-Schoberer E., Zittel W.
WHySE Wind-Hydrogen Supply of Electricity Markets – Technology – Economics
Wind Power for the 21 st Century, Kassel, Germany, 25-27 September 2000

Bermejo J.
Fuel Cells and Hydrogen Research in the European Union
2004 DOE Hydrogen and Fuel Cell Program Review, Philadelphia, 24 May 2004

Dutton A.
Wind Energy And The Hydrogen Economy: A New Commercial Opportunity?
European Wind Energy Conference (EWEC), London, 22-25 November 2004

Basic Research Needs for the Hydrogen Economy
Report prepared by the Argonne National Laboratory on the Basic Energy Sciences Workshop on
Hydrogen Production, Storage, and Use, 2004. Can be downloaded from

Eide, P., Hagen E. F., Kuhlmann M., Rohden R.
Construction and commissioning of the Utsira Wind / Hydrogen Stand-alone Power System
Published in the proceedings of EWEC 2004, 22-25 November 2004. Downloadable from

Fjermestad Hagen
personal communication

Gamma D.
Personal communication
AccaGen SA, August 2005

Gonzalez A., McKeogh E., Gallachoir B. O.
The role of hydrogen in high wind energy penetration electricity systems: The Irish case
Renewable Energy 29 (2003) 471–489, available on-line at www.sciencedirect.com

Hart D,
Hydrogen power: The commercial future of “the ultimate fuel”
Financial Times Energy Publishing, p. 36-38 1997

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Market Potential Analysis for Introduction of Hydrogen Energy Technology in Stand-Alone Power
Final report of Altener contract No. 4.1030/Z/01-101/200, downloadable from
http://www.hsaps.ife.no , 2004

High Level Group for Hydrogen and Fuel Cells
Hydrogen Energy and Fuel Cells: A vision of our future
European Commission, 2003, DG RTD, DG TREN, EUR 20719 EN

INTA Solar Hydrogen Facility
IEA Hydrogen Implementing Agreement Task 11: Integrated Systems, Final Report of Subtask A:
Case Studies of Integrated Hydrogen Energy Systems, Chapter 6 of 11, 2000, downloadable from

IEA Hydrogen Co-ordination Group (HCG)
Hydrogen & Fuel Cells; Review of National R&D Programs
IEA 2004, ISBN 92-64-10883-1

Hydrogen Production R&D; Priorities and Gaps
IEA Hydrogen Implementing Agreement – Hydrogen co-ordination Group, 2005

Kreuter W., Hofman H.
Electrolysis: the important energy transformer in a world of sustainable energy
Int. J. Hydrogen Energy, 23(8), 1998

Lipman T. E., Ramos R., Kammen D. M.
An Assessment of Battery and Hydrogen Energy Storage Systems Integrated with Wind Energy
Resources in California
California Energy Commission, PIER Energy-Related Environmental Research. CEC-500-2005-136.
Downloadable from http://www.energy.ca.gov/pier/final_project_reports/CEC-500-2005-136.html

Lymberopoulos N., Zoulias E.I., Varkaraki E., Kalyvas E., Christodoulou C., Karageorgis G.N.,
Poulikkas A, Stolzenburg K.,
Hydrogen as an alternative product for wind park developers
Proceedings of MedPower Conference, Lemessos, Cyprus, 14-17 Nov. 2004

Lymberopoulos N.
Personal communication with Prof. F. P. Neirac and Dr. J. Labbe
Visit to Ecole des Mines des Paris, Centre of Energy Studies, Sophia Antipolis, June 2005
Lymberopoulos N.
Personal communication at PIEL stand, Rome, 2005

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Merten J.
Market strategies for the Implementation of PV/Hybrid systems in Southern Europe”
Appendix to the Final Report of the Thermie Project SME 1468/97/NL, 1998.

Millet P, Andolfatto F and Durand R
Design and performance of a solid polymer electrolyte water electrolyser
Int. J. Hydrogen Energy 21(2): 87-93, 1996

Neagu C, Jansen H, Gardeniers H, and Elwenspoek M
The electrolysis of water: An actuation principle for MEMS with a big opportunity
Mechatronics: 571-581, 2000

Newborough, M.
A report on electrolysers, future markets and the prospects for ITM Power Ltd’s Electrolyser
Downloadable from www.h2fc.com/Newsletter/PDF/ ElectrolyserTechnologyReportFINAL.doc

Riis T.
Realising the Hydrogen Future: Sustainable Hydrogen; Direct Water Splitting and Hydrogen from
IEA presentation, 2004

Strategic Research Agenda of European Hydrogen and Fuel Cell Technology Platform
July 2005, can be downloaded from https://www.hfpeurope.org/hfp/keydocs

Trogisch, S., Baske, W. E.
Biogas Powered Fuel Cells
ISBN 3-85487-626-2, 2004, Trauner Verlag

Turner J. A.
Hydrogen production pathways.
Science 285, 687 (1999).

Van der Stegen JHG, Van der Veen AJ, Weerdenburg H, Hogendoorn JA, and Versteeg GF
Application of the Maxwell-Stefan theory to the transport in ion-selective membranes used in the
chlor-alkali electrolysis process
Chemical Engineering Science 54: 2501-2511, 1999

Varkaraki E., Zoulias E., Lymberopoulos N.
1st year Progress report – Contribution of CRES
EVK4-CT2001-00058 contract RES2H2, confidential document, 2002

Varkaraki E., Zoulias E., Lymberopoulos N.
3rd year Progress report – Contribution of CRES
EVK4-CT2001-00058 contract RES2H2, confidential document, 2004

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World Energy, Technology and Climate Policy Outlook 2030
EC DG RTD, 2003, EUR 20366

Strategy Report on Research Needs in the Field of Hydrogen Energy Technology
Hydrogen Strategy Group of the Federal Ministry of Economics and Labour, 2005, downloadable
from http://www.wiba.de/english/frames.htm

Zoulias E., Glockner R., Lymberopoulos N., Tsoutsos T., Vosseler I., Gavalda O., Mydske H., Taylor
Integration of hydrogen energy technologies in stand-alone power systems analysis of the current
potential for applications
Available on-line from www.sciencedirect.com

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AccaGen SA

Casale Chemicals

European Hydrogen and Fuel Cell Technology Platform

ErreDue s.r.l.

Gesellschaft für Hochleistungselektrolyseure zur Wasserstofferzeugung (GHW)

Hydrogenics corporation

IEA Hydrogen Implementing Agreement

IEA Case Studies of Integrated Hydrogen Energy Systems

Linde Gas


RES2H2 project web site

Stuart Energy

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Industrial electrolysers are mainly operated in alkaline medium, because corrosion problems are more
severe in acidic medium. Conventional alkaline electrolysers are normally operated at near ambient
pressures and have a monopolar configuration. Advanced alkaline electrolysers are built in the
bipolar filter press configuration, and are operated at pressures ranging from 3 to 30 bar. The
standard hydrogen purity at the exit of an alkaline electrolyser is approximately 99.8%vol., the rest
being oxygen and water vapour. By adding a drying and deoxidiser unit, generally called
‘purification unit’, it is possible to attain a hydrogen purity of min. 99.999% vol.

Information on the different suppliers has been gathered by studying the brochures of companies, in
websites, by requiring information directly to the suppliers or to their clients, by personal testing of
equipment, and in publications. Except for one supplier that uses the PEM technology for
electrolysis, all the commercial electrolysers presented here by alphabetical order are alkaline.

Although the technology of electrolysis is well established, there is still a considerable margin for
price reductions. Until now, most manufacturers of hydrogen generators have sold their units on a
one-by-one basis, which did not allow for real economies of scale. The greatest part of the hydrogen
generators installed are of low capacity, up to 5 Nm3/h H2, because they are used to replace hydrogen

An overview of the prices of hydrogen generators by different suppliers, based on offers during the
period 2000-2002, are presented in Figure 5, as a function of hydrogen capacity. The name of the
suppliers has been removed, because many of the offers are not officially valid any more, and the
prices may have changed.

                       Price (KEuro)










                            0   10     20   30   40     50     60      70       80   90   100   110   120
                                                      Capacity (Nm 3 /h H 2 )

       Fig. 31 Prices of electrolysers based on offers (2000-2002) by different manufacturers

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The cost of electrolysers increases with decreasing size and can be even an order of magnitude lower
per Nm3 produced for a 10x increase in production capacity, as shown in the next figure

                                                                    Supplier 1 (Alkaline)
                            80                                      Supplier 2 (Alkaline)
                                                                    Supplier 3 (Alkaline)
                                                                    Supplier 4 (Alkaline)
     Price (k€ / Nm / h)

                            30                                      Supplier 5 (Alkaline)
                                                                    Supplier 6 (PEM)

                            25                                      Supplier 7 (Alkaline)
                                                                    Supplier 8 (Alkaline)
                            20                                      Supplier 9 (Alkaline)
                                                                    Supplier 10 (Alkaline)



                                 0   10 20 30 40 50 60 70 80 90 100 110 120
                                     Hydrogen production capacity (Nm / h)
 Fig. 32 Electrolyser component costs obtained from 10 major suppliers in Europe[H-SAPS, 2003]

13.1. AccaGen SA
AccaGen is a company involved in the production of hydrogen technologies including high pressure
electrolysers, hydrogen storage and handling equipment and fuel cells (alkaline and PEM). The AGE
family of electrolysers involves models producing 1 to 100 Nm3/hr of Hydrogen at 10 bar. Units
operating at 55 bar have been sold while development work aims for 200 bar electrolysers. The
company has been collaborating with Casale Chemicals using their proprietary VOLTIANA
electrolyser cells. [AccaGen web site, Gamma 2005]. They have developed their own control strategy
and recently their own electrolysis module for high pressure operation.

AccaGen has provided a 55 bar electrolyser to the PURE wind-hydrogen installation to the Unst
community of the Shetland islands.

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                         Fig. 33 The AGE 1.0 electrolyser of AccaGen SA

13.2. Casale Chemicals SA (& Metkon-Alyzer)
Casale Chemicals SA is based in Lugano, Switzerland, and supplies advanced alkaline electrolysers
in the range 0.5 – 100 Nm3/h H2. Hydrogen is delivered at 5-30 bar pressure, at 99.8% standard
purity, which becomes 99.999%, if a purification unit is added. The electrolysers are certified by
TÜV, and, because of the increased safety of the devices, Casale Chemicals is the only supplier that
is insured by Lloyds for operation on off-shore drilling platforms. The initial concept of these
electrolysers is due to the company Metkon-Alyzer, which has supplied them for decades, before
Casale Chemicals took up and increased their reliability. Casale Chemicals has the richest reference
list as supplier of solar powered electrolysers. Grid and solar powered hydrogen generating units
have been supplied to KFA-Forschungszentrum Juelich in Germany, ENEA in Italy, INTA in Spain,
Norsk Process in Norway and Hydrogen Systems in Belgium, among others [Casale web site].

     Fig. 34 Picture of process part of Casale Chemicals 25 kW electrolyser [RES2H2 project]

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13.3. ErreDue
The Italian company ErreDue s.r.l. provides low cost units in the range of 1 to 64 Nm3/hr. The
specific energy consumption is 6 kWh/Nm3 H2 for a 99.7% H2 purity. The standard design pressure
of the electrolysers is 6 bar, because the usual clients (metal processing) do not need higher
pressures. However, according to the manufacturer, it seems possible to increase the operating
pressure to 10 bar with minor modifications, at low extra cost. The price of these alkaline
electrolysers is lower than the price of all other manufacturers (except the Italian company PIEL) by
a considerable margin.

                           Fig 35 ErreDue electrolyser [Erredue web site]

13.4. Gesellschaft für Hochleistungselektrolyseure zur Wasserstofferzeugung (GHW)
GHW mbH has been founded by Linde AG, MTU-Friedrichshafen and HEW (Hamburgische
Electricitäts-Werke AG). Their alkaline electrolyser delivers hydrogen at 5-30 bar, with the bipolar
cell stack completely encapsulated in a pressure vessel and surrounded by the feed water. Operating
temperature may be as high as 150ºC, and cell efficiencies of more than 80% can be achieved with
current densities of 10 kA/m2 (Kreuter W., 1998). The construction is very heavy and bulky,
compared to electrolysers where the pressure is kept inside the bipolar cell stack. The company is
developing a product line with capacities ranging from 0.5 to 2 MW.

GHW has constructed the 100-kW-pilot-electrolyser at the Munich airport. The electrolyser is
operated with a 40%w KOH solution at 130ºC, 30 bar and 2500 A over 0.25 m2 electrodes. The
temperature of the electrolysis is kept constant with the help of a large heat exchanger between the
electrolyte and the water in the pressure vessel. Initially, the heat exchanger was made of nickel but,
due to severe corrosion at the feed water side, nickel had to be replaced by a metal with 25% Ni as
basic material and monel for valves and sensors. In order to avoid corrosion problems in the pressure
vessel, pure nickel (2.4060, more than 99% nickel) had to be used as inner shield for the steel vessel
and monel (2.4360) for valves, pipes and flanges (Kreuter W., 1998).

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13.5. Giovanola Freres
Giovanola Freres SA in Switzerland builds atmospheric pressure electrolysers according to Bamag
technology, in unit capacities of 3 to 330 Nm3/h hydrogen output. The specific energy consumption is
4.8 kWh/Nm3 H2 for a 99.9% H2 purity.

13.6. Hydrogenics
Hydrogenics is a Canadian company operating in the US, Europe and Asia, active in the fields of on-
site hydrogen generation, fuel cells and fuel cell test systems. In the field of hydrogen generation,
Hydrogenics has been specialising on PEM electrolysers. Recently the company has joint forces with
Stuart Energy of Canada that are specialising on alkaline electrolysers. Stuart Energy has acquired
Hydrogen Systems of Belgium, who were the original developers of the Vandenborre Inorganic
Membrane Electrolysis Technology (IMET®), now offered by Hydrogenics. In this way they have
expanded their atmospheric pressure electrolyser experience to pressurised electrolysers.

Hydrogenics offers the HyLYSER hydrogen refuelling system that incorporates PEM electrolysers
capable of delivering 2.5 or 65 kgH2/day.

      Fig. 36 The 2 kg/day (left) and the 65kgH2/day (right) HyLYZER refueler of Hydrogenics
                                        [Hydrogenics web site]

13.7. Linde
Linde AG is based in Germany. They produce the HYDROSS electrolyser product line, which is part
of their ECOVAR portofolio. They range from 5 to 250 Nm3H2/hr at purities up to 99.9 % without
additional purification and up to 99.999% or even higher with purification and up to 25 bar pressure.
Their electrolysers are skid mounted and can be placed inside a container for outdoor installation.

                      Fig. 37 The HYDROSS 10 unit of Linde [Linde web site]

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13.8. Norsk Hydro
Norsk Hydro Electrolysers is based in Norway, with more than 170 hydrogen generating units
already supplied throughout the world. The company manufactures a variety of products. The
atmospheric pressure electrolysers are built in the range of 60 to 485 Nm3/hr. High pressure
electrolysers operating at 15 bar are available for the range 10-65 Nm3/hr. The company can also
provide hydrogen filling stations.

Norsk Hydro was one of the core partners of the wind-hydrogen installation at the Utsira island. The
company is also very active in various international or EU fora and committees, while being an
ardent supporter of hydrogen communities.

            Fig. 38 Norsk Hydro atmospheric (left) and pressurised (right) electrolysers

13.9. PIEL
The PIEL division of ILT Technology s.r.l., installed in Italy, manufactures alkaline electrolysers
with technical characteristics similar to ErreDue, at equally low prices. Low pressure models (up to 3
bar) produce hydrogen with 99.5% purity and a capacity of 1 to 15 Nm3/hr and are suitable for
welding and generally metal processing applications. Medium pressure electrolysers (up to 8 bar)
come in the range of 3 to 16 Nm3/hr. Lastly there is a 82 kW high pressure unit (Fig. 39) producing
14 Nm3/hr at 18 bar with a 99.5% purity. It should be noted that the energy consumption of PIEL
electrolysers is of the order of 7 kWh per Nm3 produced.

A containerised vehicle hydrogen filling system has been developed by PIEL, consisting of a
4Nm3/hr electrolyser, a purifying section and a 200 bar compressor that is a modified air compressor
normally used for filling air bottles used in scuba diving. The complete system including the high
pressure hose has a price of the order of 100,000 Euro [Lymberopoulos, 2005].

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Fig. 39 The 18 bar / 14 Nm3/hr electrolyser of PIEL (left) A 4 Nm3/hr unit used for vehicle refuelling
                                          [Piel web site]

13.10. Proton Energy Systems
Proton Energy Systems is based in the United States, and has recently commercialised the first
hydrogen generators based on electrolysis with Proton Exchange Membranes. Hydrogen capacities
range from 0.5 Nm3/h for the HOGEN® 20 model to 10 Nm3/h for the HOGEN® 380 model. The
specific energy consumption is higher than for alkaline electrolysers, namely 6 kWh/Nm3 H2 but the
hydrogen produced is of ultra high purity (99.999%) and delivered at high pressure (13 bar). Two
years ago, the company started an effort for significant cost reduction, focusing mainly on three key
elements of the electrolyser: the cell stack, the power conditioning and renewables interface, and the
system components. The electrolysis cell stack is addressed using strategies that have been
substantially proven in fuel cell hardware. A characteristic of these PEM electrolysers is that oxygen
is vented at atmospheric pressure and cannot be delivered at 13 bar, like hydrogen, without an
external compressor.

                     Fig. 40 The HOGEN RE electrolyser for RES applications

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For RES applications, the company provides the HOGEN RE system as an experimentation platform
which incorporates a HOGEN 20 or 40 model hydrogen generator, a sophisticated DC to DC power
supply, and a flexible software operating system that allows for several modes of operation.
According to the company’s brochure, this electrolyser needs AC power from the electricity grid for
running the controls and ancillary systems, while the renewable source output can be connected
directly to the electrolyser cell stack (DC source: 60-200 VDC, 150A max).

13.11. Stuart Energy
Stuart Energy is a Canadian-based company with three main product lines, which come in small,
medium or large sizes, and service three key markets: industrial, regenerative and transport. It was
founded in 1948 and, until recently, focused on industrial applications, where hydrogen is used in
processes such as the manufacture of fibre optics, integrated circuits and float glass. The electrolyser
is scalable and they fabricate electrolysers producing between 1 and more than 1000 Nm3/h

Stuart Energy recently acquired Hydrogen Systems of Belgium, expanding their product range to
include pressurised electrolysers. Their range includes products with a capacity of 1 to 60 Nm3/hr at
10 to 25 bar pressure. The specific power consumption is 4.8 to 4.9 kWh per Nm3, including rectifier
and auxiliaries losses.

  Fig. 41 Stewart Energy electrolyser incorporating Vandenborre IMET technology [Stuart Energy
                                             web site]

13.12. Teledyne Brown Engineering
Teledyne Energy Systems, a unit of Teledyne Brown Engineering Inc., based in the USA,
manufactures alkaline electrolysers for capacities ranging from few liters to 150 Nm3/h H2. Standard
delivery pressure is up to 7 bar, but the largest series operate at temperatures up to 15 bar. The
standard purity is 99.7%, but 99.9998% vol. is available with an optional purifier. The total
efficiency of the plant is approximately 6.1 kWh/Nm3 H2. The budgetary price of a 11.2 Nm3/h
generator at 7 bar pressure and 99.999% purity is 150’000 USD

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Some companies active in the development of small scale reformers are listed below. Large units like
those applied to refineries are considered a mature technology.

14.1.Johnson Matthey
Johnson Matthey is developing an autothermal reformer called Hot-Spot aimed to be used for
methanol reforming on board vehicles. The reformer starts using a POX reaction. Once water is fed
in, H2 output increases by 50% and the reaction becomes autothermal. Apparently 100% of the
CH3OH is converted leaving CO to the cleaned prior to use in a fuel cell.

14.2.Argonne National Laboratory
The Argonne National Laboratory is another autothermal reformer developer, aiming for a compact,
quick starting reformer. Catalysts have been developed for a variety of fossil and renewable fuels
including methane, methanol, ethanol, petrol and diesel. The catalysts have shown a tolerance for up
to 30ppm sulphur containing fuels. The fabrication of catalysts in the form of micro-channels has
lead to a 3-5 times reduction in the size of the reformer. Designs have been made for 5-10 kW units
(refers to the power of a fuel cell that can be driven from the gas of these reformers).

14.3.Ceramic Fuel Cells
Ceramic Fuel Cells Ltd, is developing a pre-reformer fuel processor that will convert hydrocarbon
fuels to a methane and hydrogen-rich reformate. This reformate will be directly used in an SOFC
where it will be internally reformed.

Helbio S.A. is a Greek company (spin-off from the University of Patras) that is active in the
development and commercialisation of hydrogen and energy production systems from renewable
sources integrated with fuel cells. The main hydrogen carriers utilised include bio-fuels such as bio-
ethanol, bio-gas and bio-oil. Other sources of hydrogen, such as fossil fuels (natural gas, gasoline and
diesel) are also being examined. [Helbio web site]

Hexion is a Dutch company developing hydrogen generators for industrial processes, automotive
fuelling and residential fuel cell applications. Its hydrogen generating equipment is based on different
modules that can be combined to generate different qualities of hydrogen from different fuels
covering pure hydrogen generators for industrial process applications, pure hydrogen generators for
automotive fuelling stations and hydrogen generators for residential applications with fuel cells
[Hexion web site]

Honeywell is developing an POX fuel processor for JP8 and diesel fuels, to be used in military
applications. The reaction takes place at high temperatures and is very fast with residence times of
the order of milliseconds. Fuels with a sulphur content as high as 500 ppm were utilised. The system
is optimised to produce high yields of H2 and CO and little carbon deposits.

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Nuvera Fuel Cells, besides developing fuel cells is also active in the development of reformers of
various types like catalytic partial oxidation, autothermal reforming and steam reforming. The ATR
is used for the reformation of a variety of fuels including natural gas, petrol (85% efficiency) or
diesel. The largest unit produced was for a 200kW fuel cell.

French company N-GHY is developing a high temperature non catalytic HSR whose Generation 1
prototype of 20kW showed multi fuel potential, with a conversion rate of more than 99%. The
reformer has been tried with diesel fuel, ethanol, rapeseed oil, rapeseed oil methyl ester (ROME) and
a mixture of diesel and ROME. The unit has been developed in the context of French Fuel cell
network “reseau PACo”.

14.9.Osaka Gas Co.
Osaka Gas is Japan’s second largest gas supplier. The company has been working with fuel cells
since the 1970s, and since then has operated and evaluated at least 55 units. Osaka Gas has developed
a compact reformer for a residential PEMFC that processes propane and natural gas. It can operate
maintenance free for 90,000 hours, and produces hydrogen with a CO concentration of less than
1ppm. It is considered as one of the most advanced in the world.

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