Biogas and biomethane: Efficiency
Leaks, landfill capture and engine losses: where the methane goes
What this tab covers How much of the energy available is actually captured or extracted, in per cent: theoretical limits, laboratory records, typical new equipment and in-service averages, each with exactly what is being measured.Raw biogas is 45-75% methane by volume. How much methane reaches a useful end depends on capture and leakage: US EPA reporting defaults assume landfill wells collect 50-85% of the gas depending on cover, and biogas plants leak on average about 6% of their output. Engines convert 26-32% of biogas energy to electricity.
Chart: Efficiency ranges
In service CommercialEfficiency by measure
| Measure | Range | Type | What is measured |
|---|---|---|---|
| Landfill gas collection, daily soil cover | 50%1 | In service | Share of generated methane collected by active wells (US EPA Greenhouse Gas Reporting Program default) |
| Landfill gas collection, intermediate cover | 65%1 | In service | As above, for intermediate soil cover or thin final cover |
| Landfill gas collection, final clay or geomembrane cap | 85%1 | In service | As above, for at least 3 feet of clay or a geomembrane cap |
| Methane retained by biogas plants | 94%2 | In service | Share of produced methane not leaked, global average (calculated from average emissions equal to about 6% of output; measurements are limited) |
| Biogas in engines (electricity only) | 26 to 32%3 | Commercial | Energy in biogas to electricity |
| Biogas combined heat and power | 40 to 85%3 | Commercial | Energy in biogas to electricity plus useful heat, depending on heat use |
Where the energy is lost
| Step | Loss |
|---|---|
| Methane leaking during feedstock handling (European measurements) | 0.1-2.4%5 |
| Methane leaking from digesters and digestate storage | 0-12%5 |
| Methane slip during upgrading to biomethane | 0.2-10%5 |
| Landfill gas not collected under a final cap | about 15% (calculated from the 85% default); all gas from areas without wells1 |
Biogas is made by microbes, so efficiency is about how much of the feedstock's energy they release as methane and how much of that methane is caught. Raw biogas holds 16-28 MJ per cubic metre; after the CO2 is removed, biomethane holds about 36 MJ per cubic metre, close to natural gas. Industrial food-processing wastes yield about 0.40 tonnes of oil equivalent per tonne, far more than manure.
Leakage matters more than in most energy systems because methane is at least 28 times more effective than CO2 at trapping heat over 100 years. A plant leaking 6% of its output loses much of its climate benefit, which is why measured leakage (0-12% at the digester, up to 10% at upgrading) is a central performance measure.
Sources
- 40 CFR Part 98 Subpart HH (Municipal Solid Waste Landfills), Table HH-3: landfill gas collection efficiencies US Environmental Protection Agency, Greenhouse Gas Reporting Program (eCFR), 2024
- Outlook for Biogas and Biomethane: A global geospatial assessment (World Energy Outlook special report) International Energy Agency, 2025
- Biomass for Heat and Power, Technology Brief E05 IEA-ETSAP and IRENA, 2015
- IEA's 2025 Outlook for Biogas and Biomethane (summary of the IEA report) World Biogas Association, 2025