Generation of heat and power from biogas for stationary applications: boilers, gas engines and turbines, combined heat and power (CHP) plants and fuel cells - The Biogas: Science, Production and Applications - page 419

maintenance and operating labour. O&M costs are comparable for gas
turbines, micro turbines, gas engines and fuel cells, and only a fraction lower
for Stirling engines. Total O&M costs range from 0.005/kWh to

€

0.02/kWh
for commercially available gas engines. Based on manufacturers' service
contracts for specialised maintenance, the O&M costs for micro turbines are
€

0.010/kWh for typical gas turbines and from 0.010/kWh to

€ € €

0.008/kWh to € 0.015/kWh and between € 0.003/kWh and € 0.01/kWh for

fuel cells.
Micro turbines are already commercially available while Stirling engines
are still mainly in development phase. Both promise much lower NO x and
CO emissions and maintenance costs. Compared with traditional gas
engines, micro turbines have better resistance to sulphur compounds and
lower exhaust emissions but are more expensive. Fuel cells are often
considered to be the small-scale plants of the future for the production of
power and heat with efficiencies of 65-75% and extremely low emissions
(3mgNO x /Nm 3 flue gas).
Micro turbines have become a popular alternative to IC engines due to
their lighter maintenance schedule, lower noise levels and lower air emission
levels. The initial cost is higher, however. Fuel cells may be an option in the
future, but costs need to come down before they become a practical
alternative for farm use. Micro turbine or Stirling engine based CHP units
are just now becoming commercially available. Both promise much lower
maintenance costs as oil changes are not required. Currently, the capital cost
of these options is still over 60% more than IC engines, but these costs are
predicted to drop dramatically with time and increased production of the
units.

17.5 References
Accettola F, Guebitz G M and Schoeftner R (2008) 'Siloxane removal from biogas
by biofiltration: biodegradation studies', Clean Technol Environ Policy, 10, 211-
218.
Allen M R, Braithwaite A and Hills C C (1997) 'Trace organic compounds in landfill
gas at seven U.K. waste disposal sites', Environ Sci Technol, 31, 1054-1061.
Chambers A K and Potter I (2002) 'Gas utilization from sewage waste', Alberta
Research Council, Edmonton. Available from: http://www.bvsde.paho.org/
bvsacd/cd08/gas.pdf [Accessed 20 September 2011].
Cox H H J and Deshusses A M (2001) 'Co-treatment of H 2 S and toluene in a
biotrickling filter', Chem Eng J, 3901, 1-10.
de Hullu J, Maassen J, vanMeel P, Siamak S, Vaessen J, Bini L and Reijenga J (2008)
'Biogas upgrading: Comparing different techniques', Eindhoven University of
Technology, Eindhoven. Available from http://students.chem.tue.nl/ifp24/Final
%20prese-nation.ppss [Accessed 10 May 2011].

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