At a glance
| Tool | Type | Price | Best for |
|---|---|---|---|
| Ember Electricity Data Explorer | Data explorer, CSV datasets and API | Free (CC BY 4.0) | Free, up-to-date national electricity mix and emissions intensity for more than 200 geographies. |
| Our World in Data: carbon intensity of electricity | Interactive chart and downloadable data | Free (CC BY 4.0) | Comparing countries' electricity carbon intensity over time in a chart you can cite and download. |
| IEA Emissions Factors 2025 | Paid dataset | Single-user licence price on request; digital multi-user licences from €1,990 (5 users) | Consistently compiled country emission factors for electricity and heat, widely used in corporate and national reporting. |
| Electricity Maps | Live map, data platform and API | 14-day free API trial; real-time carbon intensity €6,000 per country per year (hourly granularity) | Hourly, real-time and forecast carbon intensity for grid zones, for operational decisions and hourly carbon accounting. |
| WattTime | Emissions data API | Free Basic plan (all signals for one region, CAISO_NORTH, plus CO₂ percentiles everywhere); paid plans on request | Marginal emissions signals for shifting electricity use to cleaner hours. |
| eGRID | Dataset, summary tables and Power Profiler tool | Free | US projects that need emission rates for their grid subregion rather than the national average. |
| European Residual Mix | Annual results (PDF) | Free | Market-based Scope 2 reporting in Europe, for electricity not covered by guarantees of origin. |
| C4B | Web app, in the browser | Free plan; paid plans from €59/month (cancellation takes effect after 12 billing cycles) or €599/year, with a 7-day free trial | Seeing the national grid's carbon intensity and generation mix next to a project's climate and energy analyses. |
How to choose
Decide which question you are answering. For a building's operational carbon or a location-based Scope 2 figure, you need the average intensity of the grid the building draws from. For deciding when to run flexible loads, marginal emissions (from the power plants that respond to a change in demand) are more relevant, which is what WattTime provides. For market-based reporting in Europe, the residual mix published by the AIB applies to electricity not covered by guarantees of origin.
Check what is counted. Some sources give direct CO₂ from combustion; others give life-cycle CO₂-equivalent, including upstream methane, supply chains and manufacturing, as Ember does. Some describe electricity generated in a country, others electricity consumed after imports and exports, as Electricity Maps does, and the IEA publishes correction factors for grid losses and trade. The same country can therefore have noticeably different values in different sources.
Match the granularity to the decision. Annual national averages (Ember, Our World in Data, the IEA) suit early design comparisons and benchmarking. In large countries, sub-national figures matter: the US EPA's eGRID gives rates by grid subregion. Hourly and forecast data (Electricity Maps, WattTime) matter for operation, storage and load shifting.
Check the year and the licence. Annual datasets are published one to two years after the fact and are revised. Ember and Our World in Data are free under CC BY 4.0, while the IEA's emission factors and Electricity Maps' commercial data are paid, with licence terms that restrict reuse.
Ember Electricity Data Explorer
Free, up-to-date national electricity mix and emissions intensity for more than 200 geographies.
- Yearly generation, capacity, emissions and demand for 215 countries from 2000, with annual data generally available up to 2025, and monthly data for 88 geographies.
- Emissions intensity in gCO₂e/kWh, overall and by source, aiming to include full life-cycle emissions.
- Updated twice a month, with CSV downloads and an API (key on request).
Good to know
- Describes electricity generated in each country, not electricity consumed after imports and exports.
- Annual and monthly, not hourly; the latest full year is not yet available for every country.
Our World in Data: carbon intensity of electricity
Comparing countries' electricity carbon intensity over time in a chart you can cite and download.
- Life-cycle carbon intensity of electricity generation in gCO₂e/kWh from 1990 to 2025, processed from Ember's data.
- Download as CSV with metadata, or use the chart's data API.
- Last updated on 30 June 2026; next update planned for 30 June 2027.
Good to know
- Annual national values only, updated once a year.
IEA Emissions Factors 2025
Consistently compiled country emission factors for electricity and heat, widely used in corporate and national reporting.
- CO₂ emission factors for electricity and heat, and for electricity only, for countries worldwide from 1990 to 2023, plus provisional 2024 factors for OECD and selected countries.
- Correction factors for grid losses and, for OECD countries, electricity trade; CH₄ and N₂O factors in CO₂-equivalent.
- Last updated September 2025.
Good to know
- Licence terms restrict reuse: work for clients, such as calculating their carbon footprint, needs a separate agreement, and publishing results in annual or sustainability reports needs at least an Enterprise licence.
Electricity Maps
Hourly, real-time and forecast carbon intensity for grid zones, for operational decisions and hourly carbon accounting.
- Location-based and consumption-based: electricity flows between zones are traced, in line with the GHG Protocol Scope 2 location-based method.
- Zones are the smallest grid subdivisions with reliable data, with country aggregates, at 5-minute, 15-minute and hourly granularity.
- Uses IPCC 2014 emission factors, more granular emissions data where available, and upstream emission factors.
Good to know
- Commercial data are priced per signal, per country and per year.
WattTime
Marginal emissions signals for shifting electricity use to cleaner hours.
- The Marginal Operating Emissions Rate (MOER) describes the generators responding to changes in load, including renewable curtailment and imports and exports between regions.
- Covers more than 200 countries and territories, with at least two years of history and 72-hour forecasts updated every 5 minutes.
- Also publishes average CO₂ and health damage signals.
Good to know
- The MOER is expressed in pounds of CO₂ per MWh, not CO₂-equivalent.
- Full data for regions other than CAISO_NORTH need a paid plan.
eGRID
US projects that need emission rates for their grid subregion rather than the national average.
- Annual output emission rates for CO₂, CH₄, N₂O and CO₂e, plus NOx and SO₂, by eGRID subregion, in lb/MWh.
- The latest edition uses 2023 data, released in January 2025 and revised in June 2025.
- The Power Profiler tool helps you find the emissions of the electricity you use.
Good to know
- United States only; annual averages.
European Residual Mix
Market-based Scope 2 reporting in Europe, for electricity not covered by guarantees of origin.
- The residual mix of each country: the electricity supply not explicitly tracked with guarantees of origin, published to avoid double counting.
- 2025 results published on 28 May 2026, including direct CO₂ emissions, calculated by the European Energy Exchange for the AIB.
- Results available for every year from 2015.
Good to know
- A market-based disclosure figure, not the physical average intensity of the grid; direct emissions use Ecoinvent factors where national values were not provided.
C4B
We make C4BSeeing the national grid's carbon intensity and generation mix next to a project's climate and energy analyses.
- Country grid carbon intensity from Our World in Data and Ember, benchmarked against other countries, with the generation mix by fuel.
- Shown in the Energy tab, including on the Free plan, next to solar radiation, PV potential and the preliminary energy balance.
Good to know
- National figures only: no regional, hourly, marginal or market-based values.
- No data download or API; for carbon reporting, use the original sources.
See your site's climate before design begins
Pin any location and get climate, comfort and preliminary energy insight your whole team can read. Start with a 7-day free trial, or book a 30-minute demo.
Frequently asked questions
What is grid carbon intensity?
The greenhouse gas emissions associated with each unit of electricity on a grid, usually in grams of CO₂ or CO₂-equivalent per kilowatt-hour. It depends mainly on the share of fossil fuels in the generation mix and changes by year, season and hour.
Where can I find electricity emission factors by country for free?
Ember's Electricity Data Explorer and Our World in Data publish annual carbon intensity by country free under CC BY 4.0. The US EPA's eGRID is free for US subregions, and the AIB publishes European residual mixes for market-based reporting. The IEA's Emissions Factors dataset is paid.
Why do sources give different values for the same country?
They count different things: life-cycle CO₂-equivalent or direct CO₂ only, electricity generated or consumed after imports and exports, with or without grid losses, and different emission factors and years. Electricity Maps, for example, notes that it uses IPCC 2014 emission factors where the IEA uses IPCC 2006 factors.
What is the difference between average and marginal emissions?
Average intensity divides a grid's total emissions by its total electricity. Marginal emissions describe the generators that respond to a change in demand at a given moment, as in WattTime's MOER. Averages suit carbon accounting and design comparisons; marginal signals suit decisions about when to use electricity.
Does C4B show regional or hourly grid carbon intensity?
No. C4B shows the national annual grid carbon intensity from Our World in Data and Ember, with a benchmark and the generation mix. For regional or hourly figures, use sources such as eGRID, Electricity Maps or WattTime.
Sources
We make C4B. Information about the other tools comes from their official websites and documentation, checked on 18 September 2026. Products and prices change, so check each vendor's site for the latest details. All product names belong to their respective owners.
- Ember: Electricity Data Explorer
- Ember: yearly electricity data
- Ember: API
- Ember: electricity data methodology (PDF)
- Our World in Data: carbon intensity of electricity
- IEA: Emissions Factors 2025
- Electricity Maps: pricing
- Electricity Maps: methodology
- WattTime: marginal CO2 signal
- WattTime: data plans
- US EPA: eGRID
- US EPA: eGRID summary data
- AIB: European Residual Mix
- AIB: European Residual Mix 2025 results
Related on C4B
Grid carbon intensity
The carbon intensity and generation mix of the national electricity grid, compared with other countries.
Preliminary energy analysis
An hourly preliminary energy balance and orientation and aspect-ratio optimization for early design.
Solar radiation and PV potential
Direct, diffuse and global solar radiation, yearly PV potential, optimal panel orientation and geothermal ground temperatures.