Question

How to calculate efficiency of biogas plant?

Answer 1

Usually the output/input or input/output ratio is used, but I would like to inform another useful metrics. I think relevant metrics could be (input electrical power + input heat) / (output methane energy content) and the ratio between input electricity and heat, or reciprocals of the aforementioned. You might also want to consider that heat input has typically much less value than output gas, assuming that the heat is excess .