Fuel cells | Archive Titles

Table 1: Fuel cell system characteristics and comparison with conventional generating systems
Characterisitc	Fuel cell type				Conventional systems
	Proton exchange membrane – pemfc	Phosphoric acid – pafc	Molten carbonate – mcfc	Solid oxide – sofc	Internal combustion engine – generator	Gas turbine	Steam turbine generator
Electrolyte	Sulphonic acid incorporated into a solid polymer membrane	Phosphoric acid	Molten lithium carbonate	A ceramic, solid oxide zirconia	–	–	–
Applicable size range (kWe)	1-250	100-1000	100-2000	1 -3000	25-5000	500-25 000	25-25 000
Projected commercial availability	2004	Available	2006	2006	Available	Available	Available
Footprint (m²/kWe)			0·056-0·372		0·020- 0·029	0·002-0·057	< 0·009
Electrical efficiency at full load (%)	40	45	45-50	45-50	25-45	25 - 40	30 - 42
Electrical efficiency at half load (%)	40	45	45 - 50	45	23-40	20 - 35	28 - 40
Heat output (% of input)	40	35	30-45	35-45	35-45	40-55	Low-grade
Operating temperature (°C)	50-90	200	650	800-1000	80-480	260-600	Low-grade
Start-up time	Seconds	Hours	Hours	> 30 minutes	Seconds	Minutes	Hours
Target equipment life (years)	5 (cell stack), 20 balance of plant	5 (cell stack), 20 balance of plant	3 (cell stack), 20 balance of plant	5 (cell stack) 20 balance of plant	4 - 20	30	30
Possible fuels (see note)	Hydrogen, natural gas, lpg, methanol, ethanol, gasoline, diesel	as pemfc plus landfill gas and biogas	as pafc and gasified coal	as pafc and gasified coal	as pemf	as pemfc and gasified coal	as pemfc and gasified coal and solid fuels
NOx emissions (g/MWh)			<9		998-1270	181-1814	816
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
Period	Fuel cell type				Conventional systems
	PEMFC	PAFC	MCFC	SOFC	Internal combustion engine – generator	Micro turbine – generator	Gas turbine	Steam turbine
Capital costs (£/kW) 2003	2,600-6,500	2000-3400	2,000-5,000	5,000-10,000	–	–	–	–
Projected 2005	1,500	1,900	1,850	2,300	200 - 820	450 - 820	450 - 570	500 - 630
Projected 2010	700	1500	950	1100	–	–	–	–
Projected 2015	500	1300	700	750	–	–	–	–
Projected 2020	300	1100	550	550	–	–	–	–
Operating costs (£/kWh) 2003	0·04-0·06	0·08	0·04 - 0·08	0·05	–	–	–	–
Maintenance costs (£/kWh) projected 2006 (see note)	0·003-0·01	0·003-0·01	0·003-0·01	0·003-0·01	0·005-0·01	0·002-0·06	0·002-0·005	0.003
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
Item
Fuel cell stack	£255,000
Fuel processor	£85,000
Plant	£113,600
Labour	£113,400
Total	£567,000
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
Spares	10% 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.