Official Standards & Sources
Slate doesn't publish its own emission factors or invent its own methodology. Every number traces back to one of the publishers below. These links go to the primary source, not Slate's summary of it, so you can verify the underlying data yourself.
Accounting framework
GHG Protocol Corporate Standard
↗World Resources Institute / WBCSD
The Scope 1, 2 and 3 framework Slate categorises every activity record into.
GHG Protocol Scope 2 Guidance
↗World Resources Institute
Location-based and market-based accounting methods for purchased electricity.
Emission factor publishers
These are the actual factor sets loaded into Slate's factor library, each with its own publisher, edition and update cadence.
UK DEFRA GHG Conversion Factors
↗Department for Environment, Food & Rural Affairs
Annual UK conversion factors covering fuels, transport, materials and more. Slate loads the 2026 flat-format edition.
US EPA GHG Emission Factors Hub
↗U.S. Environmental Protection Agency
US emission factors for fuels, mobile sources and Scope 3 categories, including the Table 9 waste disposal factors used outside the WARM comparison.
EPA eGRID
↗U.S. Environmental Protection Agency
US grid subregion emission factors, the basis for location-based Scope 2 electricity in the US.
UK DESNZ Fuel Mix Disclosure
↗Department for Energy Security and Net Zero
Residual fuel mix data used for market-based Scope 2 electricity in the UK.
Canada ECCC Emission Factors and Reference Values
↗Environment and Climate Change Canada
Grid electricity consumption intensity for Canada's 13 provinces and territories, 2023–2027, derived from the National Inventory Report. The basis for location-based Scope 2 electricity in Canada.
Ember Yearly Electricity Data
↗Ember (open data, CC BY 4.0)
Grid emissions intensity for all 55 African countries, including Nigeria, from 2019 to each country's latest year. The basis for location-based Scope 2 electricity in Africa. Lifecycle basis.
IPCC 2006 Guidelines for National GHG Inventories
↗Intergovernmental Panel on Climate Change
Stationary and mobile combustion, industrial processes, agriculture and land-use factors, across multiple volumes.
IPCC 2019 Refinement
↗Intergovernmental Panel on Climate Change
The 2019 update to the 2006 Guidelines, used where a category has been refined since the original publication.
Waste
Climate science
Water
A note on these links
Slate is not accredited or certified by any of these organisations, and none of their standards require accreditation to use, GHG Protocol, DEFRA, EPA, IPCC and GRI all publish openly for exactly this kind of self-applied use. If a factor edition shown here looks out of date, it means Slate hasn't imported the newer release yet, check the primary source for the latest version.