Solar Hydrogen and Fuel Cells A Revolutionary and Sustainable by oaw14128

VIEWS: 37 PAGES: 8

									                                GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009



Solar Hydrogen and Fuel Cells: A Revolutionary and Sustainable Source
of Energy
         Abu-Hamatteh, Z.S.H.
         Al-Balqa' Applied University, Salt-Jordan
         Besieso, M. S.
         Senior Technical Advisor, Ministry of Energy and Mineral Resources, Jordan

         Jordan is a non-oil producing country. Its basic energy requirements are obtained from imported oil and natural gas from
         different sources. Energy import costs create a financial burden on the national economy. Jordan spends more than 35% of
         its gross domestic products on the purchase of energy at current oil prices. Significantly, Jordan has abundance of solar
         energy with solar radiation considered among the highest in the world. The annual daily average solar irradiance is 5-7
         kWh/m2. A major problem that accompanies all renewable energies is the storage; however, implementing solar hydrogen
         system, such problem may be eliminated. The current investigation focus on the prospects of using hydrogen generated by
         solar photovoltaic cells and electrolyzes water to produce hydrogen that contains calorific value three times more than that
         of the conventional fuel, besides being much cleaner and safer. Hydrogen is the storage and the medium to transport the
         provided energy. Therefore the developing and to applying such alternative energy sources and technology, in order to
         meet requirement without shortage and at reasonable and constant prices is a priority. Electrolyzing water by photovoltaic
         system, fuel cells types and operational description, economical and environmental characteristics are discussed herein.
         Fuel cells have been identified now by automotive industry as the most likely new technology to replace internal
         combustion engine. Also fuel cells have been in service providing power to various applications. Fuel cells have moved
         beyond the experiment stage, they make sense in today’s market place particularly where environmental concerns are
         paramount.

                                                                              oil shale, solar, wind, biogas and hydro energy utilization.
1. INTRODUCTION                                                               Jordan has initiated extensive programs leading to the
                                                                              promotion of available, new and renewable energy
   Energy is vital for the processes of production and                        resources to conserve part of its imported oil. It is
manufacturing and, as such, it is a key element of                            expected that according to the National Energy Strategy,
sustainable development which means meeting the                               Alternative fuel will participate in around 40% of total
economic, environmental, and social needs of today’s                          energy use in Jordan by 2020.
society without compromising the opportunity of future
generations to do the same. Sustainable development                              Our sun is a giant nuclear fusion reactor running on
stands for the needs on our common future. Current                            hydrogen. Each second it converts 564 million tons of
patterns of global energy use are not sustainable. The                        hydrogen to 560 million tons of helium through the fusion
fossil fuel period is an era not an age and highly limited in                 process. The loss of 4 million tons of mass equates 91
time therefore, it is critical for the world to view what                     billion Twh of energy (Twh = 1 million MWh). This is
remains of the fossil fuel era as transition.                                 more energy in one second than 6 billion nuclear power
                                                                              plants would produce in one year. Astronomers have
   The desert sunny area of the region with abundance                         determined that the sun’s energy has remained relatively
solar radiation that can capture the solar energy and                         constant over the last century and this solar constant will
transmit the power via the power grid loop or the hydrogen                    continue to be 1.35 kW per m2 for about the next four
generated to export it to local market and to industrial                      billion remaining years [3, 4, 5].
countries similar to oil or natural gas, sparing the use of
fossil fuels for higher economic benefits. Most of the                          The sun’s interior composed of dense gases (70%
scientists and experts now agree that the age of fossil fuels                 hydrogen and 28% helium). Under very high temperature
is closing and that the hydrogen will be the fuel choice for                  of 15 million ºC, hydrogen atoms are fused together to
the future. Hydrogen is the candidate and most logical                        form helium. Deep within the sun and stars, nuclear fusion
form of energy to use as the only safe, pollution free                        converts hydrogen into helium. The energy that is released
choice left to use to power the planet. We have the                           when four hydrogen atoms become a helium atom is the
responsibility to develop and to apply alternative                            energy that fuels all life [2].
technologies, in order that coming generations can be sure
to meet their energy requirement [1, 2].                                        The sun could be the solution to all energy supply
                                                                              problems-already now and in future [6]. The sun radiates
  Jordan enjoys a substantial potential of new and                            many times more energy down to earth than we require.
renewable energy sources. The most important domestic                         We just have to find ways of using this energy. In
sources of indigenous energy are natural gas, renewable                       photolysis, sunlight is used to split water. Two photolytic
energy and oil shale. Considerable efforts have been made                     processes are being explored: (1) photo biological
and great progress has been achieved in the application of                    methods, in which microbes, when exposed to sunlight,
                            GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

split water to produce hydrogen, and (2) photo electrolysis,   early internal combustion engine developed in 1820.
in which semi-conductors, when exposed to sunlight and         Hydrogen is both flammable and buoyant so it dissipates
submersed in water, generate enough electricity to produce     more rapidly. Hydrogen has often been called the perfect
hydrogen by splitting the water [7, 8].                        fuel. Its major reserves on earth are water which is
                                                               inexhaustible. The use of hydrogen is compatible with
                                                               nature rather than intrusive. We will never run out of
2. DISCUSSION                                                  hydrogen [9, 10, 11].
   Hydrogen is considered as the most promising source of         Hydrogen will likely play a key role in future electricity
energy which is a renewable fuel and can be extracted by       storage. Photovoltaic blends well with this technology for
renewable energy sources. Hydrogen is the most abundant        producing the hydrogen. An electrolyzer technology
material in the universe which makes up more than 90% of       already existing may allow taking a leading role in this
the composition of the universe. It is the third most          important future area. One way to avoid making carbon
abundant element in the earth’s surface (70%) and is found     dioxide is to stop burning fossil fuels and rely on
mostly in water and organic matters. When hydrogen is          renewable energy sources. When it comes to storing solar
generated from renewable sources, its production and use       energy for use at night or on cloudy days, hydrogen is a
is part of a clean, cyclic process, thus offering a non-       very promising alternative.
polluting, in–exhaustible, efficient and cost effective
energy system that considered as a primary energy source
                                                               2.1. Fuel Cells
in the world’s sustainable energy future. Hydrogen was
first identified in the late 16th century, this mysterious        Sir William Robert Grove developed the first working
which yielded water when burned was named hydrogen,            prototype in the year 1839 representing the foundation
meaning water production [1].                                  stone for today's fuel cell technology. This prototype
                                                               consisted of two platinum electrodes which were
  Hydrogen is the lightest element in the universe. It is an   separately surrounded by a glass cylinder. One of the
energy carrier, not an energy source, meaning that it stores   cylinders was filled with hydrogen the other with oxygen.
and delivers energy in a usable form. In its pure form         Both electrodes were immersed in diluted sulphuric acid,
(H2), it is a colorless and odorless gas. However, since it    which was the electrolyte and created the electric
combines easily with other elements, hydrogen is rarely        connection. At the electrodes voltage was produced. This
found by itself in nature and is usually found as a part of    voltage was very low and therefore Grove linked several
other compounds, including fossil fuels, plant material,       fuel cells to get a higher voltage. Only in the 1950`s,
and water [6]. Hydrogen can be produced using a variety        against the background of the Cold War, his idea was
of domestic energy resources-fossil fuels, such as coal and    taken up again. Space travel and military technology
natural gas, with carbon capture and sequestration;            required compact and powerful energy sources [9].
renewable, such as biomass, and renewable energy
technologies, including solar, wind, geothermal, and              Fuel cells and their ability to cleanly produce electricity
hydropower; and nuclear power [3, 4].                          from hydrogen and oxygen are what make this system
                                                               attractive as a new technology for transportation use and
  Hydrogen condenses at -252.77 °C. Liquid-hydrogen            for homes and other uses. Fuel cells function somewhat
has a specific gravity of 70.99 g/l. Because of that           like a battery—with external fuel being supplied rather
hydrogen has the highest energy density in relation to         than stored electricity—to generate power by chemical
mass of all fuels and energy carriers: 1 kg hydrogen           reaction rather than combustion. They typically consist of
contains as much energy as 2.1 kg natural gas or 2.8 kg        numerous small cells in layers, rather than a single large
petrol [2].                                                    one [4].

  Independent from the base material hydrogen is always           Spacecraft and submarines require electric power and it
generated by a process. For this energy is needed. It is an    is not possible to work with internal combustion engines.
advantage of the use of hydrogen that the energy for its       Because of batteries being too heavy for spacecrafts,
generation has not necessarily to be taken from fossil         NASA in the Apollo program decided in favor of the
sources. Wind power, solar energy and waterpower are           direct chemical generation of electric power by fuel cells.
primary energy sources as well. The production of              The civil use of fuel cells became interesting only during
hydrogen is not really new. At the moment world-wide           the last years.
every year 500 billion cubic meters of hydrogen are
produced, stored, transported and used. This is happening        At the beginning of the 90’s scientists and engineers
mostly in the chemical and petrochemical industry.             developed different new concepts and technologies which
                                                               made it possible to increase efficiency continually and to
  Being lighter than air (one ft3 hydrogen weight just         decrease costs at the same time. Today fuel cells can be
0.005 1b), hydrogen was used to inflate observation            used for many different applications, such as vehicle
balloons as early as 1783 and also served as a fuel for an     engines, residential heating systems and even big power
                            GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

stations with a power rating of several megawatts as well       power. The output DC electricity is then converted to AC
as for smallest applications like in mobile phones or           in the power conditioning section.
mobile computers. The fuel cell really has the potential to
revolutionize the world of energy technology.                      The positive ions travel through the electrolyte to the
                                                                other catalyst electrode where they combine with oxygen
   There are several different types of fuel cells using        fed to that electrode—and electrons—to produce water and
different catalysts and electrolytes. Today, there are          heat. The necessary electrons are drawn through an electric
various types of fuel cells that’s developed or being           circuit external to the cell, creating the electrical
developed. Each fuel cell has their own characteristics but     generation. Fuel cells give us a very efficient way to
similar in how they work. Each type has different potential     produce electric power and heat. In the whole circle of
applications. Solid polymers or proton exchange                 renewable energies they are the final element. The
membrane fuel cells operates at relatively low temperature      electrolyte membrane looks rather like a thick sheet of
(85 °C), they have high power density, can start instantly      food wrap and can be handled easily and safely. The anode
at full capacity and can adjust quickly to variable power       and cathode are prepared by applying a small amount of
demands. Polymer Electrolyte Membrane (PEM) fuel cells          platinum black to one surface of a thin sheet of porous,
are the prime candidates for light and duty vehicles. Fuel      graphitized paper which has been wet – proofed with
cells types are: polymer electrolyte membrane; direct           tephlon. The electrolyte is sandwiched between the
methanol; alkaline; phosphoric acid; molten carbonate,          cathode and anode and the three components are then
solid oxide and regenerative fuel Cells.                        sealed together under heat and pressure to produce a single
                                                                membrane / electrode assembly. This assembly which is
  Several benefits can be expected by using fuel cell           the heart of the fuel cell is less than 1mm thick. Fuel cells
technology, the may be summarized as following:                 of the 1960’s were expensive (due to large amount of
• Environment benefits because of no combustion;                platinum needed to manufacture fuel cell). In the late
• Flexibility in the types of fuels that can be used with       2006, significant reduction in the amount of platinum
    fuel cell technology;                                       needed for fuel cells were obtained.
• Relieves the reliance on existing natural resources
    used for energy consumption;                                3. PHOTOVOLTAICS
• Higher quality of power and energy efficient;
• Safe, quiet and reliable;                                        Photovoltaic cells (PV) convert the sunlight directly into
• Fuel cells can run continuously for long periods of           electricity which can be easily moved but not easily
    time before servicing is required;                          transported so it can be used in the electrolysis system
• Fuel cells provides another method of generating              when storage is needed. The electrolysis converts water
    energy;                                                     into hydrogen and oxygen. The hydrogen gas can easily be
• Fuel cells converts hydrogen into water, it matches           converted to electrical power in a fuel cell. PV and fuel
    the eco-system (natural cycle of the biosphere);            cells contain no moving parts; they are reliable and have
• They are clean-efficient (zero emissions) and they are        service life of more than 20 years. Solar cells (PV) use
    modular in design;                                          semiconductor material to convert sunlight directly into
• No moving parts, no maintenance. (Cold burning);              electricity. Because PV produces power only when the sun
• No transmission lines, the disappearance of electric          is shining, an independent PV system must include
    grid are a possibility;                                     batteries to store energy when the sun is not shining.
• Fuel cells can start instantly at full capacity and can       Where the electrical system is or near its capacity, adding
    adjust quickly to variable loads;                           PV can be cheaper than upgrading electrical transformers
• Decentralized electric plants sized according to the          and distribution wires. Use semiconductor material to
    needs – small enough to power a car (and a house at         convert sunlight directly into electricity. Because PV
    night);                                                     produces power only when the sun is shining, an
• Fuel cells are perfect for co-generation.                     independent PV system must include batteries to store
                                                                energy when the sun is not shining. Where the electrical
                                                                system is or near its capacity, adding PV can be cheaper
2.2. Operation Principle                                        than upgrading electrical transformers and distribution
  When fuel is passed over one side and air over the other,     wires.
the hydrogen atom splits into a proton and an electron
where a chemical reaction occurs, which involves a flow           The PV cell was discovered in 1954 by Bell Telephone
of negatively charged oxygen ions across a thin sheet layer     researchers examining the sensitivity of a properly
of platinum which induces the gas for separation. This          prepared silicon wafer to sunlight. Beginning in the late
creates an exploitable electric current which will continue     1950s PVs were used to power U.S. space satellites. The
to flow for as long as the fuel and air supplies are            success of PV in space generated commercial applications
maintained. Fuel cell stack which is a series of electrode      for PV technology. The simplest photovoltaic systems
plates interconnected to produce a set quantity of electrical   power many of the small calculators and wrist watches
                                                                used everyday. More complicated systems provide
                            GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

electricity to pump water, power communications                 and oxygen gas is the classic example of electrochemistry.
equipment, and even provide electricity to our homes.           The principle is easily demonstrated by connecting
                                                                platinum-tipped wires to a battery, immersing them in tap
   Photovoltaic technology is used to produce electricity in    water fairly close to each other, and observing the gas
areas where power lines do not reach. In the developing         bubbles produced. Hydrogen is the most energy-rich fuel
countries, it is significantly improving living conditions in   known and burns to give almost pure and drinkable water.
rural areas; it can be incorporated in packages of energy
services and thus offer unique opportunities to improve            State–of–the–art industrial electrolyzers based on
rural health care, education, communication, agriculture,       polymer–electrolyte membrane separators now operate
lighting and water supply.                                      routinely at over 85%. The reason for producing H2 from
                                                                electricity, which of course consumes energy, is to create a
   In the industrialized countries, programs that provide       form of energy storage useful for indefinite or long time-
incentives for the incorporation of photovoltaic systems in     scales. H2 has the potential to serve as both an energy
building roofs and walls have tallied up thousands of           storage means and an energy carrier [8].
completed projects in the United States, Japan and Europe.
Annual worldwide sales of photovoltaic systems are                 When an electric current is passed between two metal
growing by around 30% and now stand at about one                plates (electrodes) through a conducting solution, H2 gas
billion dollars. Solar thermal technology could                 is formed at the negative electrode (the cathode) and
theoretically supply about half of Europe industrial            oxygen at the positive electrode (the anode). The
process heating needs.                                          conducting solution (the electrolyte) is normally alkaline –
                                                                potassium or sodium hydroxide. Gas output depends
   Solar cell is a device for converting energy from the sun    directly on the electric current. For example, 1000 amperes
into electricity. Solar cell is made from highly processed      flowing between single anode-cathode pair of electrodes
silicon, a material known to display the photoelectric          will produce 0.418 normal m3 of H2 and 0.209 normal m3
effect, in which light causes electricity to flow in a          of O2 per hour [7].
material. Silicon is a type of material called a
semiconductor is a conductor where electricity can flow           Electrolysis at 1.48 volts (corresponding to 3.5 KWh per
freely, and an insulator, where electrons are board tightly     normal m3 of H2) would be 100% efficient in the
to their atoms and do not flow freely. The Sunlight hits the    conventional sense. Practical electrolysers today achieve
electrons, some of the electrons gain enough energy from        efficiency of 85%. Electrolytic H2 can therefore be
the sunlight to jump and become free to conduct electricity     regarded as storable form electricity. At present, the use of
(direct current DC). A typical PV module measures about         H2 as a storage medium generated by solar power is at the
0.5 m2 produces about 75 watt of DC power in full sun.          research and development stage.
Wiring modules in series increases the voltage available
while wiring in parallel increases the current available.       5. HYDROGEN STORAGE
The PV industry took 27 years to hit its first gigawatt
Einstein was the first to discover that sunlight releases a        A hydrogen economy will appear when adequate storage
stream of electrons.                                            technology exists, allowing us to tap and trade renewable
                                                                power sources. Finding a cost-effective method of storing
                                                                hydrogen on a vehicle is a challenge. While hydrogen
4. ELECTROLYSIS
                                                                contains more energy per weight than any other energy
  The obvious way to make hydrogen is electrolysis              carrier, it contains much less energy by volume. This
which operates by an electrical current in a solution which     makes it difficult to store a large amount of hydrogen in a
has long been used to separate oxygen and hydrogen in           small space, like in a gas tank of a car. Hydrogen can store
water. The conventional way to produce hydrogen by the          energy like it is stored today by oil or by natural gas. In
solar energy is that electricity from photovoltaic (PV)         general there are three different ways of storing hydrogen,
panels can be used to turn an electrolyzer, a device which      i.e., storage in pressure tanks; storage of liquid hydrogen
splits water into its elemental parts, hydrogen (H2) and        and storage via absorption. In the recent years, several
oxygen (O2). When solar energy is not available, the            technologies have been developed [7, 8]. They are
hydrogen is recombined with oxygen in a fuel cell, an           discussed herein.
electrochemical power plant that directly converts the
chemical energy in hydrogen into electricity. This              5.1. High-Pressure Tanks
electricity can be used in the same ways as grid power, and
even to power cars [1].                                           Hydrogen gas can be compressed and stored in storage
                                                                tanks at high pressure. These tanks must be strong,
  Electrolyzers convert abundant chemicals into more            durable, light-weight, and compact, as well as cost
valuable ones by the passage of electricity, normally by        competitive. When it is necessary to store large amounts of
breaking down compounds into elements or simpler                hydrogen in a future energy economy then hydrogen can
products. Electrolysis of liquid water into hydrogen gas        be pressed into subterranean cavern storages. There it can
                            GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

be stored under a pressure of up to 50 bars. In France and     indicated that the use of graphite nanofibers to increase
in the USA this method is already in use. In Germany           current hydrogen storage capabilities by a factor of ten. If
natural gas is stored in such caverns. They could be used      true, the new discovery means that a car can travel 5000
for the storage of hydrogen in future. Tanks for the storage   miles on a single hydrogen cartridge, the empty cartridge
of pressurized gas differ by their construction according to   could then be recharged or exchanged for a full one. There
the type of application which determines the required          would be no need to establish a hydrogen infrastructure
pressure levels. For the most part stationary tanks have a     and the two greatest obstacles to use hydrogen, lack of
lower pressure level because this type of storage is           infrastructure and onboard storage problems would be
cheaper. The requirements for mobile applications, for         removed [13, 14].Carbon nanotubes are examples of
example in a motor vehicle, are quite different because        materials that reversibly store hydrogen. Other sorbents
there is not much room for tanks. For such applications        may be able to store hydrogen at room temperature.
tank pressure is increased up to 700 bars in order to store    Materials are under study that release hydrogen by a
as much hydrogen as possible in a very confined space.         chemical process on the vehicle. These materials are then
Pressure tanks used to be made from steel and therefore        removed and" regenerated "off-board, either at the fueling
were very heavy. Modern pressure tanks are made from           station or at a central processing plant.
composite materials (coal-fibre composite materials with a
thin internal aluminum liner) and they are much lighter.       6. SAFETY AND ENVIRONMENT
Delivery of pure hydrogen gas is carried out by 700 miles
in US, UK and Germany. It is small compared to natural            Global warming may be the most divesting
gas but this indicates that there are hydrogen pipelines in    environmental problem human beings have created and the
operation today to deliver hydrogen to users successfully      toughest to solve since the world is largely dependent on
[10, 11].                                                      fossil fuels causing this problem. The only way to solve
                                                               this environmental problem is by producing commercial,
                                                               zero-emission power machines. From the environmental
5.2. Liquid Hydrogen
                                                               perspective, the best transitional fuel may be the one that
  Hydrogen can be stored as a liquid. In this form, more       leads most quickly to the use of fuel cells using hydrogen
hydrogen can be stored per volume, but it must be kept at      from renewable sources. It is hoped that these problems
cold temperatures (about -253°C). Materials-based storage      would become things of the past. Scientists have
of hydrogen: Hydrogen can be stored within solid               calculated that an immediate 60% reduction in CO2
materials, such as powders, or liquids [12].                   emissions would stop the build up of CO2. If the increase
                                                               of greenhouse concentrations is not limited, the predicted
5.3. Reversible Metal Hydrides                                 climate change would place stresses on natural and social
                                                               systems unprecedented in the past 10,000 years [13].
   Hydrogen combines chemically with some metals,
which can result in higher storage capacity compared to           As global ecosystem exploitation and destruction
high-pressure gas or liquid. These materials can be re-        reaches its end point sometime in the first half of this
filled with hydrogen while on the vehicle. Metal hydride       century and natural environments cease to exist outside
storage technology uses certain metal alloys which are         protected enclaves, our reliance on the bounties of nature
storing hydrogen like a sponge becoming saturated with         well end. We well then depend entirely on how well we
water. The hydrogen is adsorbed by the metal thus              can manage the remaining biological and physical assets
building metal hydrides. If a metal hydride is filled with     of our plant, to sustain the existence of human population
hydrogen it emits heat [7, 8].To regain the hydrogen heat      whose current growth rate is only exceeded by its
must be supplied. Referring to the volume metal hydride        accelerating consumption of natural resources. In addition
storage has a very high storage capacity. Unfortunately        we will need to manage these resources within the context
those storages are quite heavy and therefore they can not      of a rapidly changing global environment. Global climate
be used in mobile applications. In addition they are very      change is a pressing factor in the non sustainability of
expensive because of the high costs of materials. Hydride      present energy use. Improved energy efficiency and the
storage is the simplest and the safest, but it increases       introduction of renewable energy sources are the most
weight. Liquid hydrogen is light, but due to its low energy    promising means for moving toward sustainability.
density which occupies three times as much volume as
gasoline. Storage as a compressed gas is inexpensive and          In order to conserve our energy resources, protect our
provides for ease of operation but its weight and bulk is      environment and improve the quality of life, a technology
the main problem. New hydrogen energy involves a new           is needed that is efficient to provide for world’s energy
type of reaction between hydrogen and heavy metals.            demand, which is clean enough to help reverse the damage
Through a process of molecular–level interaction,              to our environment. That technology is the hydrogen fuel
significant amount of energy in the form of heat are           cells which have the ability to generate electricity in big
released. The reaction takes place under extremely             power plants, transportation and, medical applications.
controlled circumstances. The claim announced in 1999 by       Fuel cells also could help decentralized the power
researchers at Northeast University in Boston–USA              industry. Hydrogen is a colorless, odorless and tasteless
                             GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

and completely non-poisonous gas. It has a specific               time due to the cost involved in generating electricity for
gravity of 0.0899g/l (Air is 14.4 times as heavy) and since       the process [15, 16, 17].
hydrogen is lighter than air, it diffuses rapidly [15, 16, 17].
Hydrogen is both flammable and buoyant, due to its                   Hydrogen production by electrolysis of water requires
buoyancy; it dissipates more rapidly than either gasoline or      3.3 kWh of primary energy produces enough liquid
natural gas in a spill. Hydrogen handling has excellent           hydrogen to produce 1 kWh of secondary power. The cost
safety record. Hydrogen also is completely non–toxic. The         of fuel cell power systems must be reduced before they
often–expressed concern about hydrogen safety is                  can be competitive with conventional technologies.
misplaced [12].                                                   Currently the costs for automotive internal combustion
                                                                  engine power plants are about $25-$35/kW; for
  Hydrogen flames have low radiant heat. An explosion             transportation applications, a fuel cell system needs to cost
cannot occur in a tank or any contained location that             $30/kW for the technology to be competitive. For
contains only hydrogen. By using hydrogen in low-                 stationary systems, the acceptable price point is
temperature fuel-cells (e.g. membrane fuel cells: PEMFC)          considerably higher ($400-$750/kW for widespread
emissions can be avoided completely. In the process of            commercialization and as much as $1000/kW for initial
generating energy from hydrogen and air-oxygen there is           applications).
only water as a reaction product (i.e. water without any
minerals, like distilled water). The use of hydrogen in fuel-        The cost of solar cells and fuel cells energy technologies
cells operating at a higher temperature-level causes              are going down (90% reduction in three decades) implying
emissions a hundred times lower than in conventional              that more markets will be open soon. In long term, solar –
power stations [13, 14].                                          generated hydrogen from seawater may become an export
                                                                  commodity mainly for countries that are blessed with high
   With regard to handling and safety there are advantages        solar radiation. Power production cost by using fuel cell
in the use of metal hydride storage tanks. Almost all of          technology is estimated at bus bar cost of C 5 /kWh which
them operate at normal pressures, there are no losses and         is close to the conventional cost of power production.
they effect a cleaning of the hydrogen. Hydrogen is               Several fuel cell manufacturers plan to commercialize fuel
released by the supply of heat and therefore the hydrogen         cells for stationary power plants at $1000/kW. At this
remains bonded in case the tank is damaged. Motor                 capital cost, fuel cells can compete with conventional
vehicles consume half of the world’s oil and account for a        power plants in providing electricity to the bulk power
quarter of the greenhouse-gas emission. Laws in California        market. PV electricity cost was $500 /watt in 1972 but by
now require that 10% of all cars sold by the year 2008            1999, wholesale prices were down to $3.5/watt and
should be zero-emission vehicles. Under the new laws, the         conversion rates now approach 31%. It is expected to
annual sales of zero-emission vehicles are expected to            become cheaper to around $ 1.0 /watt in 2010. Moreover,
surpass 200,000. In order to meet this demand, American’s         wholesale of wind power costs down 80% over the past
three big automakers–Ford, Chrysler and GM have formed            decade to C 3.5/kWh but wind could also drop as low as C
a partnership for a new generation of vehicles [18].              2.5/kWh by 2010 [19, 20].

7. SYSTEM ECONOMICS                                                  The long distance transmission of hydrogen gas through
                                                                  pipelines would be more efficient than transmission of
   The challenge in solar hydrogen-fuel cell development          electricity across power lines. A combination of fuel cell /
for practical applications has to improve the economics           electrolyzer can be used and the hydrogen can be stored or
through the use of low cost components with acceptable            piped and then later can be used. This technology makes it
life and performance. Although natural gas will likely            possible to provide a continuous supply of power being
provide the earliest affordable feedstock for hydrogen,           not dependent on the level of solar radiation. It is expected
today's costs are prohibitively expensive. The cost of            that by 2010, at least 150 hydrogen-powered buses will be
producing and delivering hydrogen from a small scale              running in regular scheduled routes in USA. In 1996 the
reformer of natural gas for a fuel cell vehicle could be as       first commercial fuel cell to run on renewable fuel was
high as $40-$50 per million BTUs with today's                     dedicated at a landfill in the city of Groton- USA. The car
technology. This would make hydrogen about four times             industry and the stationary power industry are both so
as expensive as gasoline at the pump [19, 20].                    huge that if one of them adopts fuel cells, it will pull the
                                                                  other one into the market and cost will drop considerably
  The first demonstration step proves that fuel cells have        [21].
reached a stage of technical maturity, at the same time;
other key issues need further investigation like reducing            There are currently few buses in Chicago and
the cost and the volume and weight. The most cost–                Vancouver that run of fuel cells where smog is a constant
efficient method currently employed in the industrial             health hazards. Most major automakers have started their
manufacture of hydrogen is steam hydrocarbon reforming.           intension to begin selling fuel cell passenger vehicles. The
Electrolysis is energy intensive and can not compete              Union of Concerned Scientists estimates that a fuel cell car
economically on a large scale with other methods at this          using gasoline would provide at best 1.5 to 2.3 times
                             GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

higher fuel economy than the same internal combustion            have been slow to gain universal acceptance as an
engine car burning gasoline, while fuel cell running on          alternative fuel.
hydrogen scores 2-8 times the gasoline-powered cars
performance.                                                        One reason is that like most new technologies, costs of
                                                                 production are still high. Recent advances in materials
  A suitable technology to store hydrogen on board a             have yielded solar and fuel cells that are simpler to
vehicle needs to be developed mainly to store hydrogen in        produce and considerably more efficient to operate.
solid-state. Such storage technologies include developing a      Through much additional work needs to be done, the
material with a sufficient high hydrogen storage capacity        development of these advances have brought the
and an ability to very quickly absorb and release hydrogen.      electrolytic production, storage, distribution of hydrogen
During the early 90s nearly every major car manufacturer         and power production from fuel cells much closer to
in the world launched a program to build a fuel cell             commercial reality. It is worth to mention that electricity
automobile. The cost of fuel cell is coming down and the         cost was 3 USD/kWh when it was first delivered from
Los Alamos Scientists have found a way to reduce the             Edison’s Power Station in 1882, yet it was successfully
necessary platinum by a factor of 40, this reduction in cost     commercialized because it delivered a better product. If
would make fuel cell complete with conventional                  solar hydrogen fuel cell follow the herd and deliver the
machines [15, 16, 17].                                           same product, then they will have to cost less and perform
                                                                 better than conventional generation since hydrogen is a
8. CONCLOSION AND                                                carbon-free energy carrier that has the potential to replace
RECOMMENDATIONS                                                  fossil fuels in every sector of the economy. The cost of
                                                                 energy should become no more at a consideration than the
  Solar–Hydrogen is increasingly seen as an ideal energy         cost of air or water. If you could free up all the energy
source that satisfies clean atmosphere requirements. The         stored in a simple glass of water, you could heat your
remaining hydrocarbon fuel resources could be used for           home for months.
purposes other than energy, such as the manufacturing of
plastics, synthetic fibers and other durable goods.              References
Conventional fossil fuels are being sold too cheaply, since
their total selling price should involve hidden costs which      [1] R. Dante, J. Lehmann and O.J. Solorza-Feria, Appl.
consumers do not see. These are the costs involved in            Electrochem., 35: 327-337, 2005.
degrading the health and the environment.                        [2] F. Orecchini, A Santiangeli and A.J. Dell Era, Fuel
                                                                 Cell Sci. Technol., 3: 75-82, 2006.
   It is expected that in the near future, every house will
generate its own needs of electricity and heat by using a        [3] S.A. Grigoriev, V.I. Porembsky and V.N. Fateev, Int.
small size stack fuel cell. Whenever excessive electricity       J. Hydrogen Energ., 31: 171-175, 2006.
generated from the solar cell on the roof, the electricity can   [4] H.K. Lee, H.Y. Choi, K.H Choi, J.H. Park and T.H
be sold and also be converted into hydrogen. This system         Lee, Jour. Power Sources 132: 92-98, 2004.
has the advantage of substituting almost existing
                                                                 [5] S.G. Meibuhr, Electrochim. Acta, 11, 1301, 1966
infrastructure such as pipelines and power lining. A
scheme for alternative hydrogen energy system must be            [6] P.H. Aurora and J.J. Duffy, Adv. Sol. Energy, 16: 371-
further developed to solve the environmental and energy          421, 2005.
crises which will contribute to sustainable development.         [7] F. Barbir, Sol. Energy, 78: 661-669, 2005.
Fuel cell systems could help decentralize the power
industry and provide low cost electricity for consumers.         [8] J. Nowotny, C.C. Sorrell, L.R. Sheppard and T. Bak,
New, cheaper ways to use solar electricity to obtain             Int. J. Hydrogen Energ., 30: 521-544, 2005.
hydrogen from water is emerging. So are methods that use         [9] A. Gallucci, L. Paturzo and A. Basile, Ind & Eng
light instead of electricity, imitating photosynthesis, but so   Chem Res., 43(10): 2420-2432, 2004.
far these are only in lab scale.
                                                                 [10] J.N. Armor, Applied Catalysis A, No. 176: 159-176,
                                                                 1999.
   Transition to hydrogen economy will require
development of a hydrogen infrastructure, storage                [11] A.L. Dicks, Journal of Power Sources, 61: 113-124,
technologies, electrolysis, hydrogen fueling stations, fuel      1996.
cell vehicles and reliable hydrogen sensors. Among the           [12] R. Nowakowski and R. Dus, Langmuir 19 6750-6758,
alternative energy carriers, hydrogen is preferred which         2003.
can be produced in a biological process (photosynthesis
using solar energy to split water). Upon utilizing hydrogen       [13] V.A. Paganin, E.A. Ticianelli and E.R. González,
energy in fuel cells, the H2 and O2 components are               Jour. Appl. Electrochem., 26: 297-304, 1996
combined to form water and energy is released in a cyclic        [14] M.A. Pena, J.P Gomez. and J.L.G. Fierro, Applied
driven by the unlimited and safe energy source of the sun.       Catalysis A, 144:7-57, 1996.
Despite its many advantages, solar hydrogen fuel cells
                          GCREEDER 2009, Amman-Jordan, March 31st – April 2nd 2009

[15] R.G. González-Huerta, J.A. Chávez-Carvayar and O.      [19] M. Zanfir, Catalytic plate reactors for endothermic-
J. Solorza-Feria, Power Sources, 153: 11-17, 2006.          exothermic reaction coupling, PhD Thesis, University
[16] L. Barreto, A. Makihira and Riahi, Int. Jour.          College London, UK, 2000.
Hydrogen Energ. 28: 267-284, 2003.                          [20] V. Plzak, B. Rohland and H. Wendt, Modern Aspects
[17] R. Charlesworth, The steam reforming and               Electrochem., 26: 105-163, 1994.
combustion of methane on thin layer catalyst for use in a   [21] K. Suárez-Alcántara, A. Rodríguez-Castellanos, R.
catalytic plate reactor, PhD Thesis, University of          Dante, and O.J. Solora-Feria, Power Sources, 157: 114-
Newcastle-upon Tyne, UK, 1996.                              120, 2006.
[18] S. Borman, Chemical and Engineering News 83 (7):
11, 2005.

								
To top