Direct Fuel Cell Experience on Renewable Biogas

Abstract

FCE (FuelCell Energy, Inc.) in Danbury, CT currently offers three commercial products; the DFC300MA, DFC1500, and DFC3000, rated 300 kW, 1200 kW and 2400 kW, respectively to operate on methane-rich fuels including bio-gas. These products use the Direct FuelCell® (DFC®), which has the special ability to generate electricity directly from a hydrocarbon fuel by reforming it inside the fuel cell and supplying hydrogen for fuel cell reactions. Biogas, which is available from distributed sources, contains 50-80% methane depending on the source, and is an excellent fuel for DFC power plants. FCE has placed over twenty biogas units ranging from 250 kW to 1.2MW around the world, achieving an electricity conversion efficiency of 45 to 49% (LHV). A unique feature of the DFC is that its performance is not impacted by the bio fuels diluted with CO2 (20-50%). In fact, the biogas plants are consistently showing a higher fuel cell conversion efficiency (~1% on a normalized basis) compared to pipeline natural gas plants. Initial DFC biogas applications focused on wastewater treatment, food processing and brewery industries where the contaminants are primarily sulfur and siloxane. FCE has used operation experience with these plants to improve the gas supply reliability, understanding of the biogas contaminants and improve removal process effectivity.