Fuel combustion emissions: natural gas, diesel, LPG and heating oil

Burning fuel in boilers, generators, kilns and company vehicles is the most common source of Scope 1 emissions. The calculation is simple, quantity × factor, but the factor has to match the unit of your data exactly. See Scope 1 emissions.

DESNZ 2026 factors by unit

kg CO2e per unit:

Natural gas is also available per cubic metre: 2.02633 kg CO2e/m³.

Gross or net calorific value?

Energy in a fuel can be stated on a gross basis (including the heat in the water vapour formed) or a net basis (excluding it). The same physical gas gives a higher kWh figure on a gross basis, so the factor per gross kWh is lower. For natural gas the two factors differ by about 11%.

Check your invoice or the supplier's terms for the basis and use the matching factor. Using a net factor on gross kWh overstates emissions by that 11%.

Biofuel blends

Road fuels sold at the pump contain some biofuel. DESNZ publishes "average biofuel blend" factors for pump diesel and petrol, and separate 100% mineral factors. Use the blend factor for fuel bought at retail stations unless you know the exact blend. DESNZ publishes the CO2 from the bio-component of forecourt fuels separately, as "outside of scopes" factors, so it can be reported separately from Scope 1.

Worked example

A small manufacturer uses, in a year:

Upstream emissions

These factors cover combustion only. The emissions from producing and delivering the fuel are Scope 3 category 3, calculated with separate well-to-tank factors on the same quantities. See category 3.