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Table 1: Fuel cell system characteristics and comparison with conventional generating systems
CharacterisitcFuel cell typeConventional systems
 Proton exchange membrane – pemfcPhosphoric acid – pafcMolten carbonate – mcfcSolid oxide – sofcInternal combustion engine – generatorGas turbineSteam turbine generator
ElectrolyteSulphonic acid incorporated into a solid polymer membranePhosphoric acidMolten lithium carbonateA ceramic, solid oxide zirconia
Applicable size range (kWe)1-250100-1000100-20001 -300025-5000500-25 00025-25 000
Projected commercial availability2004Available20062006AvailableAvailableAvailable
Footprint (m²/kWe)  0·056-0·372 0·020- 0·0290·002-0·057< 0·009
Electrical efficiency at full load (%)404545-5045-5025-4525 - 4030 - 42
Electrical efficiency at half load (%)404545 - 504523-4020 - 3528 - 40
Heat output (% of input)403530-4535-4535-4540-55Low-grade
Operating temperature (°C)50-90200650800-100080-480260-600Low-grade
Start-up timeSecondsHoursHours> 30 minutesSecondsMinutesHours
Target equipment life (years)5 (cell stack), 20 balance of plant5 (cell stack), 20 balance of plant3 (cell stack), 20 balance of plant5 (cell stack) 20 balance of plant4 - 203030
Possible fuels (see note)Hydrogen, natural gas, lpg, methanol, ethanol, gasoline, dieselas pemfc plus landfill gas and biogasas pafc and gasified coalas pafc and gasified coalas pemfas pemfc and gasified coalas pemfc and gasified coal and solid fuels
NOx emissions (g/MWh)  <9 998-1270181-1814816
Note: these represent sources of raw fuel which need to be processed (or reformed) to provide the fuel required to power the fuel cell, which is hydrogen in the case of pemfc and pafc and hydrogen or carbon monoxide for mcfc and sofc.
Table 2: Cost comparison for stationary generation equipment
PeriodFuel cell typeConventional systems
 PEMFCPAFCMCFCSOFCInternal combustion engine – generatorMicro turbine – generatorGas turbineSteam turbine
Capital costs (£/kW) 20032,600-6,5002000-34002,000-5,0005,000-10,000
Projected 20051,5001,9001,8502,300200 - 820450 - 820450 - 570500 - 630
Projected 201070015009501100
Projected 20155001300700750
Projected 20203001100550550
Operating costs (£/kWh) 20030·04-0·06 0·080·04 - 0·080·05
Maintenance costs (£/kWh) projected 2006 (see note)0·003-0·010·003-0·010·003-0·010·003-0·010·005-0·010·002-0·060·002-0·0050.003
Note: current maintenance costs for fuel cells are high due to the limited number of units and manufacturers in the marketplace, and possible issues concerning reliability.
Table 3: Breakdown of typical project costs
Fuel cell stack£255,000
Fuel processor£85,000
Delivery to site (outside USA)£20,000
Installation costs (site and application dependent)
Standard (generation only)£50,000
Non standard£80,000
CHP (including project management, design, site preparation and additional plant)£100,000-£200,000
Spares10% of capital cost
Maintenance£ 16,000 - £ 26,000 pa
Fuel stack  
Fuel stack replacement£ 150,000 every 4 years
Fuel stack refurbishment£ 120,000 every 4 years
Total (£/kW) 3549-4415 (excluding stack replacement/refurbishment)
Note: excludes inflation beyond second quarter 2003, incoming gas service, builders work in connection with services, main contractors overheads and profit and attendances, professional fees, vat.