Emission factors are used to compute emissions related to electricity consumption with the simple formula:

Figure 1: Schematic representation of emission factors

They thus describe how much carbon is emitted per unit of energy used.

The carbon-intensity factors used by Electricity Maps are computed through life-cycle analysis.

Emissions from direct operations (ex: carbon emitted during the combustion of coal), emissions resulting from the extraction of resources required to build up installed capacity (ex: emissions from the exhaust of the trucks used in coal mines), and end-of-life related emissions (ex: emissions resulting from the dismantlement of a coal power plant) are all accounted for.

For some commercial purposes, we also support operational (or direct) emission factors. These emission factors only account for emissions that directly result from the operation of a given electricity source.

The emission factors used by Electricity Maps come from different sources

• Default emission factors

See our Default emission factors wiki entry for details

• Zone specific emission factors

For some zones, Electricity Maps is able to source specific emission factors.

For example, for the US and the EU direct power plant emissions are publicly available. It is thus possible to match these emissions with power plant generation data and compute per power plant emission factors, which can be aggregated at a zone level.

There are also some reputable sources, such as peer-reviewed scientific papers, or meta-analysis that offer direct emission factors with a precise geographical granularity.

There are dedicated wiki entries for regions of the world for which Electricity Maps uses zone specific emission factors, where you can read more about the exact methodology used:

• US emission factors
• European emission factors

The emission factors of storage is calculated based on average intensity of the grid, see detailed description of how/why we do it this way.

Using regional emission factors increases the accuracy and quality of Electricity Maps' data. We are open to contributions to continuously enhance our dataset. In order to be added on the map, the data submission must follow these guidelines:

• Verify data sources
• Create a pull request with the following:

1. Zone configuration file is updated
2. EMISSION_FACTORS_SOURCES.md is updated. (You can run poetry run python scripts/update_emission_factors_sources.py once the zone configuration has been updated)

Sources should be formatted using the MLA citation style, you can use this free citation generator if you are unsure about how it should be styled.