Energy and Greenhouse Gas Analysis for Biogas Power Plants

In order to assess the efficiency of an alternative power source and to provide a meaningful comparison with fossil fuel based power sources, a complete accounting of all energy input and output streams, as well as all greenhouse gases, is necessary. We present this analysis for a 1.45 MW (0.71 MW electrical) biogas power plant operating with 70% corn silage and 30% cow dung feedstock. We find net energy ration of 8.0, a net efficiency of 1.2% of converting solar energy into electricity and usable heat, and that only 16 g CO2 per kWh are generated in the process. If all greenhouse gases are considered, our process even actively reduces the total greenhouse gas load on the atmosphere. In terms of producing transportation biofuels our plant provides 3.8 times more yield per hectare than bioethanol plants.