Power Generation from Biogas using SOFC – Results for a 1 kW e Demonstration Unit

A stand‐alone system for power generation from biogas‐based on a commercial SOFC module in the 1 kW e range shall demonstrate its applicability to biogas, quantify the efficiency gain compared to conventional combined heat and power technology and justify further development toward SOFC modules in the hundreds of kilowatt range. The system includes biogas cleaning, combined dry and steam reforming, electrochemical oxidation of synthesis gas, offgas burning, and heat usage for steam generation and support of the endothermic reforming reaction. The system demonstrated a performance of 1 kW e at 52% gross efficiency for a synthetic biogas containing 55 vol.% CH 4 during 500 h in the lab. In addition, the performance using real biogas derived from the wastewater treatment process of a sugar plant was demonstrated for different operating points. Based on the experimentally validated results, it is possible to predict the benefit of operating larger SOFC biogas systems. Investment costs of 2.5 times compared to the conventional technology of a 75 kW e biogas unit get paid off due to higher electricity revenues over time.