Biogas To Electricity Calculator

Work out biogas to electricity instantly with clear inputs, formula shown and shareable results.

About Biogas To Electricity Calculator

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.

Formulas

Biogas energy

Energy (kWh) = biogas volume (m3) x methane fraction x 9.94

Electrical output

Electricity = energy x engine electrical efficiency

Worked example

With the default values below, Biogas To Electricity Calculator returns Daily Electricity Generated of 2,266.32. Change any input above and every figure here is recalculated in your browser.

Inputs used

Biogas Volumeminimum 0 m3/day: 1,000 m3/day
Methane Contentaccepts 1–100 %: 60 %
Engine Electrical Efficiencyaccepts 1–60 %: 38 %
Operating Hours Per Dayaccepts 0.01–24 hours: 22 hours

Results

Daily Electricity Generated: 2,266.32
Generator Capacity Required: 103.015
Biogas Energy Content: 5,964.00
Recoverable Heat: 2,504.88

Step by step

1Values used
2Biogas energy
3Electrical output
4Daily Electricity Generated= 2,266.32
5Generator Capacity Required= 103.015
6Biogas Energy Content= 5,964.00
7Recoverable Heat= 2,504.88

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
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.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

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.

Frequently Asked Questions

How much heat does the digester itself need?

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.

Does the gas need cleaning?

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.