tc02e.com's emission factors come exclusively from open-licensed or public-domain sources. Several of those licenses require attribution — this page provides it, and every calculation result also shows the source, year and license of the exact factor used.
IEA-derived factors were removed from the active dataset in July 2026 because the IEA license is incompatible with a free commercial product; they are retained internally only for the audit trail of historical calculations.
UK DEFRA/DESNZ GHG Conversion Factors
Open Government Licence v3.0
Contains public sector information licensed under the Open Government Licence v3.0. Source: UK Department for Energy Security and Net Zero, Greenhouse Gas Reporting: Conversion Factors.
https://www.gov.uk/government/collections/government-conversion-factors-for-company-reportingSingapore Energy Statistics (EMA)
Singapore Open Data Licence
Grid emission factor from the Energy Market Authority of Singapore, Singapore Energy Statistics, used under the Singapore Open Data Licence.
https://www.ema.gov.sg/resources/singapore-energy-statisticsEmber Yearly Electricity Data
CC BY 4.0
Country grid intensities from Ember's Yearly Electricity Data, licensed CC BY 4.0. Values are provisional annual averages pending re-verification against the downloaded dataset.
https://ember-energy.org/data/yearly-electricity-data/US EPA GHG Emission Factors Hub / eGRID
Public domain (US federal work)
US grid and combustion factors from the US Environmental Protection Agency (public domain).
https://www.epa.gov/climateleadership/ghg-emission-factors-hubIPCC 2006 Guidelines defaults
Public domain
Fuel combustion defaults from the IPCC 2006 Guidelines for National Greenhouse Gas Inventories.
https://www.ipcc-nggip.iges.or.jp/public/2006gl/EXIOBASE 3
CC BY-SA 4.0
Spend-based intensities derived from EXIOBASE 3, licensed CC BY-SA 4.0. Derived published tables (including this page's factor lists) remain under CC BY-SA 4.0.
https://www.exiobase.eu/