Fuel cell operation on anaerobic digester gas: conceptual design and assessment

The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at wastewater treatment plants during the process of treating sewage anaerobically to reduce solids. The economic feasibility study shows the fuel cell is economical where plant electricity costs are 5 ¢/kW h or higher, based on entry level fuel cell costs of $3000/kW. FCs are one of the cleanest energy technologies available, and the widespread use of this concept should result in a significant reduction in global warming gas and acid rain air emissions. Additionally, technology evaluation focused on improving a commercial phosphoric acid FC power plant operation on ADG is described.