Work out biogas to electricity instantly with clear inputs, formula shown and shareable results.
Biogas energy is its methane content times methane's calorific value of 9.94 kWh per cubic metre. A gas engine converts 35-42% to electricity and around 42% to recoverable heat, of which part is needed to keep the digester at temperature. Generator size follows from daily energy divided by planned running hours.
Biogas energy
Energy (kWh) = biogas volume (m3) x methane fraction x 9.94
Electrical output
Electricity = energy x engine electrical efficiency
Biogas is flammable and contains toxic hydrogen sulphide. Gas handling, engine rooms and digesters must comply with the applicable gas safety and confined space regulations.
Typically 20-35% of the recovered heat in a temperate climate, more in winter. Only the surplus is available for export, which is often the difference between a viable and unviable project.
Yes. Hydrogen sulphide must be removed to protect the engine, and moisture and siloxanes removed to protect valves and catalysts. Untreated gas destroys engines rapidly.