Conversion factors for the energy content of fuels (so-called ‘heating’ or ‘calorific values’) need to be used when preparing information on energy consumption. Heating values can be direct or indirect data, originate from multiple sources, and be expressed in different ways (e.g. energy per weight or energy per volume).
Direct data on heating values will result from the analysis of the heat content of fuels used and from which a conversation factor is derived. This is typically done by very large energy consumers (and emitters) who need to know well the fuels they use, for example, power production from fossil fuels.
Indirect data on heating values can comprise, for example, data from fuel suppliers, national statistics data or engineering/technical factors representing usually accepted average figures foreach fuel type, often reported as ranges (e.g. biodiesel 39–41 MJ/kg).
Common sources of indirect data for heating values are:
- 2006 IPCC Guidelines for National Greenhouse Gas Inventories (Table 1.2, page 1.18), also used as a reference for Annex VI of the EU ETS Monitoring and reporting regulation;
- the UN Energy Statistics Yearbook, which provides statistical series of Heating values for different fuels and countries (see the supplement to the 2021 Energy Statistics Database);
- GHG national inventories reports (NIR) submitted to the UNFCCC; and publications from energy statistics by the national statistics or energy authorities.
- It is important to note that calorific value changes across jurisdictions.