Fuel Defra

This category allows the user to calculate emissions from a certain amount of fuel, measured in mass, energy or volume. It follows the methodology presented in the most recent Defra data and advice.

What the user needs to know

In order to use this category the user must know the amount of fuel used and the units for that measurement - either mass, volume or energy. The user also needs to know, if measuring their fuel use in terms of energy, whether that energy is net or gross.

The data presented here provide emission factors on a Net Calorific Value (CV) and Gross CV basis. If the fuel use is measured in terms of mass or volume the emission factor is the same in both Net and Gross cases. If calculating in terms of energy useage the Net CV emission factors are significantly higher so it is important that the correct emission factor is used. Natural Gas consumption figures quoted in kWh by suppliers in the UK are generally calculated on a Gross CV basis from the volume of gas used. Therefore, the Gross CV emission factor should be used by default for calculations of Natural Gas emissions, unless the supplier states otherwise.

Gross CV or Higher Heating Value (HHV) is the CV under laboratory conditions. Net CV or Lower Heating Value (LHV) is the useful calorific value in typical real world conditions. The difference is essentially the latent heat of the water vapour produced.

How to use this category

This category has three drill downs. Use the first drill, fuel, to select the fuel being used from the following options.

• aviation spirit

• aviation turbine fuel - similar to kerosene, refined to a higher quality for aviation use

• burning oil - also known as kerosene or paraffin used for heating systems

• coal (industrial) - industry use including collieries, iron and steel, autogeneration, cement production, lime production, public sector, stationary combustion, railways and agriculture

• coal (electricity generation) - power station use only

• coal (domestic) - domestic use coal only

• coking coal

• compressed natural gas (cng)

• diesel

• fuel oil

• gas oil

• lpg

• lubricants

• naphtha

• natural gas

• other petroleum gas

• petrol

• petroleum coke

• refinery miscellaneous

The third drill-down, unit is used to select which units the fuel use will be entered in, either mass, energy or volume.

The user must then enter a fuel use value as either the mass, energy or volume profile item values. Only one of these profile item values can be used for any single calculation and this must match the unit drill-down selected previously.

The algorithm then multiplies the fuel use value by the appropriate emission factor to give a result of kgCO₂e, which includes contributions from carbon dioxide, nitrous oxide and methane.