Biomass Cofiring Potential and Experiences in The Netherlands

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					Biomass Cofiring Potential and
Experiences in The Netherlands



  René van Ree, Rob Korbee, Theo de Lange,
     Simon Eenkhoorn, Bas Groenendaal

 Netherlands Energy Research Foundation ECN
              Biomass Systems




International AFB-net Cofiring Workshop
 Grenoble, France, 14-15 September 2000
                     CONTENTS


•   Dutch renewable energy policy -> contribution of biomass
•   Available coal and natural gas fired power plants
•   Status current cofiring projects
•   “Advanced” co-firing concepts
•   Technical, environmental, and economic constraints
•   Discussion/conclusions
•   ECN’s co-firing activities
•   Acknowledgement
                 Dutch Renewable Energy Policy
                  Contribution of Biomass

•10% renewable energy in 2020 (288 PJth,a.f.f.u.)                    Summer 2000
                                                                    policy agreement
•Biomass contribution: 26%                                          government and
                                                                         power production
                               Biomass policy goal [PJth, a.f.f.u.]         companies:
        Technology              2000       2007        2020                  6 Mt CO2-
   Domestic wood comb.            8          8            8              reduction in 2010
   Industrial wood comb.          5          5            5                      ->
Co-firing in fossil fuel fired    3         18           20               3 Mt by cofiring
        power plants                                                      biomass in coal
 Decentral CHP production         2          6           30             fired power plants
Biogas (waste disposal sites,                                             -> 20% cofiring
         digestion)               6          8            8
           Others                 -          -            4
            Total                24         45           75
           ECN’s Cofiring Activities (1)
• System Assessments
  - steady-state integral thermodynamic system analysis
       -> overall mass and energy balances
       -> net electrical system efficiencies [%LHV]
  - technical system assessments
       -> system bottle-necks -> “de-bottle-necking”
  - environmental system assessments (incl. LCAs)
       -> gaseous, liquid, solid system emissions
       - applicable air/water emission constraints
       - commercial applicability of solid waste streams (ashes, gypsum)
  - financial-economic system assessments
       -> specific investment costs [Euro/kWe]
       -> investment decision criteria (POT, NPV, ROI)
       -> costs of avoided CO2-emissions
       -> biomass fuel costs versus power production costs
               incl. applicable subsidies, fiscal regulations
             ECN’s Cofiring Activities (2)
• Experimental work
-   Thermal conversion (gasification, pyrolysis, combustion) of
    biomass/waste streams
    fuel gas/syngas/flue gas compositions/contaminants
    slagging/fouling behaviour
-   Fuel gas/syngas clean-up/conditioning technologies for application of
    biomass-derived gas in downstream equipment
    particles, tars, HCl, H2S, NH3, alkali-metals, H2/CO-ratio, ...
-   Bottom-ash and fly-ash characterisation
    the influence of biomass-derived contaminants on the quality of these ash
    fractions and on their commercial applicability

            For the experimental work ECN owns a large variety
                    of lab-scale and bench-scale facilities
                         (see conference proceedings)
             Acknowledgement



   The work presented has been performed in the framework
of the in-house RD&D-programme “ENergy Generation In the
            Natural Environment (ENGINE) of ECN
                     and was co-funded by
      the Dutch Agency for Energy and the Environment
                          (NOVEM)
                  Coal Fired Power Plants
                    in The Netherlands
 Power plant          Owner              Net capacity        Lifetime
                                            [MWe]
Gelderland-13            EPON                602            1983-2011
   Amer-8                 EPZ                645            1981-2010
   Amer-9                 EPZ                600            1994-2023
 Borssele-12              EPZ                403            1988-2012
Maasvlakte-1              EZH                518            1989-2013
Maasvlakte-2              EZH                518            1988-2012
Buggenum-7              for sale             253            1994-2023
 Hemweg-8                UNA                 630            1995-2024
          Total coal fired power production capacity: 4170 MWe

                    EPON = Electra-Bel (Belgium)
                    EPZ = ESSENT (Netherlands)
                   EZH = Preuen-Elekra (Germany)
                    UNA = Reliant Energy (U.S.A.)
            Natural Gas Fired Installations in
                    The Netherlands
• Natural gas fired boilers: mainly for industrial heat production
  more than 900 installations, overall capacity > 4600 MWth

• Natural gas fired gas turbine installations for CHP production
  more than xxxx installations, overall capacity > 4325 MWe
  - power production: gas turbines integrated with a condensing steam
    turbine (low heat/power-ratio) -> overall capacity > 6000 MWe
  - > 60% built after 1990 -> dry low-NOx combustion chamber
  - < 40% built before 1990 -> water/steam injection facilities
                             Current Cofiring Activities
                                in The Netherlands

 Power plant        Type of        Type of fuel        [kt/yr]   % cofiring   CO2-em.red.        Status
                    cofiring                                      (energy)      [kt/yr]
Gelderland-13       indirect     demolition wood        60            3          110          operational
   Amer-8            direct        paper sludge         75           0.3          11          operational
   Amer-9         gasification   demolition wood        150           5          170           test phase
 Borssele-12         direct    phosphor furnace gas     23            3            ?          operational
Maasvlakte 1/2       direct      Biomass pellets1       150           5           78          operational
                     direct        poultry litter       40            4           60             tested
 Buggenum-7          direct          variety             ?            ?            ?             study
  Hemweg-8           direct       sewage sludge         75            3           92             tested
           1
               Demolition wood / sewage sludge: negative view from the public (heavy metal emissions)
                  2
                    Biomass pellets: 60 w% paper/cardboard, 24 w% waste wood, 16 w% compost
                Short-term Additional Cofiring
                Activities in The Netherlands (1)
• EPON
• Cofiring percentage of the Gelderland-13 power plant 3 -> 10% (relatively
  clean fuels), by: 1) expanding the current indirect cofiring capacity, 2) direct
  cofiring, 3) upstream gasification (without add. gas clean-up).
• Cofiring of sewage sludge/high calorific waste streams in the gas-fired
  Eems power plant (1675 MWe). Technology: upstream gasification with a
  very extensive fuel gas clean-up system. Maximum cofiring capacity: 100
  MWth (3% total energetic natural gas input).
• EPZ
• Direct cofiring of 6-12 kt/yr sewage sludge in Borssele-12 power plant.
• Co-firing capacity expansion in all their coal fired power plants.
  Technologies: direct cofiring and upstream gasification (and pyrolysis?)
               Short-term Additional Cofiring
               Activities in The Netherlands (2)
• EZH
• Increasing the quality of the Biomass pellets that are currently being cofired
  (5%) in the Maasvlakte power plant by potentially integrating an additional
  fuel drying process.
• Direct cofiring of 40 kt/yr poultry litter (4%) planned.
• UNA
• Direct cofiring of 75 kt/yr sewage sludge (3%) in the Hemweg power plant
  planned.
• Potentially two vacuum pyrolysis units (Pyrovac) for cofiring purposes
  planned. Capacity: 120 kt/yr biomass.
• Demkolec
• Direct and indirect cofiring of biomass and waste streams in the
  Buggenum coal fired IGCC plant (253 MWe). Plant for sale.
  Future activities depending on new plant owner.
           “Advanced” Future Cofiring Concepts
             ECN study co-funded by NOVEM
• To meet Policy Agreement: current 0 - 5% -> 20% cofiring in coal fired
  power plants (CO2-emissions ~ gas fired plants). Longer-term > 20%

• Which cofiring concepts are available (coal fired power plants and natural
  gas fired CCs)?
• What is their potential?
  - net electrical biomass conversion efficiency [%LHV]?
  - necessary additional specific investment costs [Euro/kWe]?
• What are the technical and environmental cofiring constraints?
• What is the financial potential of the cofiring concepts?
  -> preferable biomass cofiring concept combinations
          “Advanced” Future Cofiring Concepts
         Technical and Environmental constraints
• Technical constraints (coal fired power plants)
• Pretreatment section: size reduction, quality control, dust explosion danger
• Boiler: large gas volume, fuel burn-out, slagging/fouling behaviour, (HT)
  corrosion/deposition/erosion danger
• Flue gas clean-up: capacity ESP, deactivation SCR-catalyst, DeSOx-
  capacity, emission constraints concerning heavy metals

-> Most of the technical problems have already been solved.
-> Further (experimental) attention need:
   - the slagging and fouling behaviour
   - the (HT) corrosion problems
         “Advanced” Future Cofiring Concepts
               Economic Constraints
Net electrical efficiency biomass [%LHV], specific costs additional investment
[Euro/kWe], operation time [hrs/year], specific financial criteria for Dutch situation
-> price of fuel that can be converted economically as function of the profit of
    the produced electricity                                Main financial criteria:
                                                            subsidy (EIA+Vamil): 25% on add. inv.
                                                            depreciation time: 10 year
                                                            tax: 35%
                                                            Coal price: 1,63 Euro/GJth
                                                            ...
         “Advanced” Future Cofiring Concepts
        Technical and Environmental constraints
• Environmental constraints
• EU air emission constraints applicable for (large-scale) power plants.
• Commercial applicability of produced solid waste streams (fly-ash, gypsum
  (bottom-ash)).
                                                                       Clean biomass fuels (EU):
                                                                       No problem emissions
• ECN-study                                                            (particles, NOx, SO2) to the
                                           Maximum allowable
                                           component content in        air expected.
                                           biomass fuel
   EU emission           Spreadsheet                                   Contaminated biomass
   constraints           with indicative                               fuels (EU): a variety of
                         power plant
                         data
                                                                       components are critical.

   Influence cofiring                      Distribution biomass fuel
   on quality of ashes                     components to the gas phase,
   and gypsum                              the solid phases (ashes, gypsum),
                                           and the liquid phase (waste water)

Contaminated fuel cofiring -> heavy metals to solids -> critical?
Clean fuel cofiring -> no critical influence on quality expected
                     “Advanced” Future Cofiring Concepts
                      Cofiring concepts and their potential
         Concept            Biomass input       Net electrical  Necessary additional     Base-case coal fired
                               [MWth]            efficiency     specific investment
                                            biomass part [%LHV]  costs [Euro/kWe]        combustion plant:
        direct cofiring       151/622               39,6               35/20             - 600 MWe
      indirect cofiring       158/649               38,0              500/285
    separate gasification                                                                - Net eff.: 40 %LHV
    - without fgcu (FW)       157/648              38,1                455/300           - 6000 hrs/yr
     -with fgcu (Lurgi)       169/695              35,6               1120/730
     separate pyrolysis
    - slow without pgcu       167/688              35,9                  895             10% / 40% cofiring
      - slow with pgcu        186/765              32,3                 1240
       - fast (Pyrovac)       166/682              36,1                  935              Base-case natural gas
        separate HTU          170/697              35,4                620/490            fired CC:
 separate combustion with     155/639              38,6                940/575            - 335 MWe
   steam-side integration
                                                                                          - Net eff.: 55%LHV
              Cofiring in a CC by separate gasification with fgcu (Lurgi)
                                                                                          - 6000 hrs/yr
 Cofiring percentage Biomass input           Net electrical       Necessary additional
[% total, energy basis]      [MWth]            efficiency          specific investment    5, 10, 20% cofiring
                                         biomass part [%LHV] costs [Euro/kWe]
        5 (6.1)                38                 44.3                    1500
      10 (12.1)                75                 44.3                    1340
      20 (23.7)               151                 44.3                    1180
                     Discussion/conclusions (1)

• Policy agreement government - power production companies concerning
  CO2-emission reduction coal fired power plants -> 20% cofiring in 2010
• Current cofiring activities: mainly direct cofiring in coal fired power plants
  (< 5% of total energetic plant input).
• Six main concepts have been identified to increase the cofiring capacity of
  coal fired power plants: further direct cofiring, indirect cofiring, separate
  gasification, separate pyrolysis, separate HTU and separate combustion with
  steam-side integration.
• Preferable concepts for clean biomass fuels (EU): direct cofiring, separate
  gasification without fgcu.
• Preferable concepts for contaminated biomass fuels: separate gasification
  with fgcu and slow pyrolysis with pgcu. A cheaper alternative could
  probably be mixing these fuels with clean fuels.
                    Discussion/conclusions (2)

• For cofiring in natural gas fired CCs, the biomass has to be gasified
  upstream, after which the fuel gas has to be cleaned extensively, before the
  gas is mixed with natural gas to be combusted in the CC.
• The main technical constraints that have to be solved (experimentally) for
  cofiring of biomass in coal fired power plants are: fouling/slagging and (hot)
  corrosion.
• The main technical constraint that has to be solved for biomass cofiring in
  natural gas fired CCs is to get a better insight in the maximum amount of
  LCG that can be burned in relatively new gas turbines with dry low-NOx
  burners.
• For clean biomass cofiring no problems are expected concerning applicable
  EU air emission constraints and the quality of produced solid waste streams.
• For contaminated biomass fuels both aspects need further research.