The grids that cleaned up fastest, 2015 to 2025
Portugal cut the carbon intensity of its electricity from 414 grams of CO2 per kilowatt hour in 2015 to 128 grams in 2025, a fall of 69 per cent. On Ember’s annual figures that is the largest ten year fall of any country generating at least 50 TWh a year. Finland is a close second, down 69 per cent from 182 grams to 57. Neither country did it by building one big thing. Both did it by removing coal and adding wind and solar at the same time.
Carbon intensity is the emissions produced for each unit of electricity delivered. It is the single most useful number for comparing grids of very different sizes, because it does not reward a country simply for being small.
The ten largest falls
Countries generating 50 TWh or more in 2025, ranked by the percentage fall in carbon intensity between 2015 and 2025 (Ember, annual):
| Country | 2015 | 2025 | Change |
|---|---|---|---|
| Portugal | 414 | 128 | -69% |
| Finland | 182 | 57 | -69% |
| The Netherlands | 551 | 254 | -54% |
| Spain | 328 | 153 | -53% |
| Greece | 604 | 325 | -46% |
| The United Kingdom | 398 | 222 | -44% |
| Brazil | 189 | 110 | -42% |
| Belgium | 215 | 126 | -42% |
| Chile | 493 | 291 | -41% |
| Germany | 504 | 334 | -34% |
Figures are grams of CO2 per kilowatt hour.
Coal leaving is what does it
In almost every case the same thing happened. Coal went from a large share of generation to almost none.
- Portugal: coal was 28.8 per cent of generation in 2015 and zero in 2025. Solar went from 1.6 per cent to 17.3 per cent, wind from 22.7 to 26.8, hydro from 16.9 to 29.7.
- Spain: coal fell from 18.5 per cent to 0.3 per cent, while solar rose from 5.0 to 21.9 per cent and wind from 17.8 to 20.4.
- The United Kingdom: coal fell from 22.4 per cent to 0.6 per cent, and wind rose from 11.9 to 29.2 per cent.
- Greece: coal fell from 43.3 per cent to 4.8 per cent, though a good part of the gap was filled by gas, which rose from 17.8 to 40.3 per cent. That is why Greece, at 325 grams, remains well above the countries above it in the table.
- The Netherlands: coal fell from 36.1 per cent to 7.1 per cent while solar rose from 1.0 to 21.1 per cent and wind from 6.9 to 25.0.
Finland is the exception to the pattern. Its coal share was only 7.5 per cent in 2015. It got to 57 grams by taking wind from 3.4 per cent of generation to 27.5, and by nuclear rising from 33.9 per cent to 39.8 per cent of a larger total.
The big grids moved less, but moved more
Percentage falls favour small systems. The largest grids in the world changed by less in proportion, and by far more in absolute terms.
China went from 670 grams to 528, a fall of 21 per cent, while its generation grew from 5,799 TWh to 10,506 TWh. Its coal share fell from 70.0 per cent to 54.8 per cent, and solar rose from 0.7 per cent to 11.2 per cent. The United States went from 505 grams to 384, a fall of 24 per cent, with coal down from 33.1 per cent of generation to 16.3 and gas up from 32.6 to 40.0. India fell from 751 grams to 671, a fall of 11 per cent, with coal still at 70.9 per cent of generation in 2025.
Europe as a bloc
The European Union average fell from 348 grams per kilowatt hour in 2015 to 210 in 2025, a fall of 40 per cent. Across the wider Europe region, which includes non EU countries, the average fell from 373 grams to 284. The EU’s coal share dropped from 24.6 per cent to 9.2 per cent over the same ten years, while solar went from 3.5 per cent to 13.1 and wind from 9.2 to 17.0.
Europe’s grids are also where the cleanest and the most carbon intensive sit close together. Norway generated at 28 grams in 2025 and Sweden at 35, while Poland was at 591 despite falling 28 per cent over the decade.
Who has barely moved
At the top of the 2025 table, Uzbekistan was at 1,000 grams per kilowatt hour, Kazakhstan at 813 and South Africa at 699. South Africa fell 12 per cent over ten years, Kazakhstan and Uzbekistan by less.
The full ranking for every country is on the carbon page, and each country’s own record back to 2000 or earlier is on its history page, for example Portugal’s and the United Kingdom’s.
How we calculated this
All figures come from Ember’s annual dataset, as loaded into this site’s export on 15 September 2026.
- Carbon intensity:
sections.annual.carbon_intensity_gco2_kwhincountries/<id>.jsonandregions/region-eu.jsonandregions/region-europe.json, at the 2015 and 2025 positions ofsections.annual.years. - Percentage change: (2025 value minus 2015 value) divided by the 2015 value.
- The ranking covers only countries whose
sections.annual.total_generation_twhfor 2025 was 50 TWh or more, which is 48 countries. Without that filter the list fills with very small systems where one new plant moves the average. - Fuel shares:
sections.annual.share_pctby fuel, same files and years. - Generation totals:
sections.annual.total_generation_twh.
Ember statistics are annual and describe completed calendar years, not present conditions. Ember revises earlier years as countries report, so a 2015 figure quoted here may differ slightly from one published in 2016. Licence details are on the sources page.