In February 2019, Britain's electricity averaged 216 gCO₂/kWh, in the moderate band (140–219 g). Gas made 42.8% of the electricity generated, nuclear 20.3%, wind 14.4% and imports 9.6%; low-carbon sources together made 45.1%. The cleanest half hour was 74 g at 04:00 on Saturday 9 February, and the dirtiest 342 g at 06:00 on Tuesday 5 February. Sunday 17 February was both the cleanest day (120 g on average) and the windiest (34.2% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Fri 1 Feb | 293 | 28.5% | 3.8% | 0.2% | 56.3% | 18 |
| Sat 2 Feb | 247 | 33.9% | 4.6% | 2.7% | 52.7% | 48 |
| Sun 3 Feb | 232 | 35.0% | 5.6% | 2.5% | 51.2% | 48 |
| Mon 4 Feb | 252 | 34.7% | 6.4% | 1.4% | 52.9% | 48 |
| Tue 5 Feb | 271 | 30.2% | 4.3% | 0.5% | 58.9% | 48 |
| Wed 6 Feb | 228 | 36.3% | 5.1% | 1.7% | 51.1% | 48 |
| Thu 7 Feb | 221 | 37.5% | 6.4% | 2.5% | 47.4% | 48 |
| Fri 8 Feb | 154 | 46.4% | 12.1% | 0.8% | 38.3% | 48 |
| Sat 9 Feb | 136 | 51.7% | 13.0% | 3.2% | 35.4% | 48 |
| Sun 10 Feb | 212 | 43.0% | 11.5% | 2.0% | 45.0% | 48 |
| Mon 11 Feb | 279 | 37.6% | 10.0% | 2.4% | 50.9% | 48 |
| Tue 12 Feb | 216 | 47.9% | 19.9% | 1.6% | 41.6% | 48 |
| Wed 13 Feb | 196 | 52.6% | 24.6% | 2.4% | 35.3% | 48 |
| Thu 14 Feb | 224 | 46.7% | 16.3% | 3.5% | 41.2% | 48 |
| Fri 15 Feb | 213 | 50.3% | 19.9% | 4.1% | 35.7% | 48 |
| Sat 16 Feb | 162 | 56.8% | 25.8% | 1.6% | 32.4% | 48 |
| Sun 17 Feb | 120 | 66.6% | 34.2% | 3.0% | 23.5% | 48 |
| Mon 18 Feb | 170 | 58.6% | 29.9% | 1.5% | 30.6% | 48 |
| Tue 19 Feb | 203 | 50.9% | 20.8% | 2.7% | 37.0% | 48 |
| Wed 20 Feb | 172 | 55.9% | 27.0% | 1.8% | 32.9% | 48 |
| Thu 21 Feb | 204 | 50.7% | 20.2% | 3.1% | 36.4% | 48 |
| Fri 22 Feb | 200 | 50.8% | 19.5% | 3.5% | 37.2% | 48 |
| Sat 23 Feb | 168 | 57.4% | 22.5% | 4.2% | 31.9% | 48 |
| Sun 24 Feb | 227 | 43.3% | 8.8% | 5.1% | 45.2% | 48 |
| Mon 25 Feb | 258 | 39.2% | 7.8% | 4.7% | 49.6% | 48 |
| Tue 26 Feb | 267 | 38.9% | 6.9% | 4.6% | 49.6% | 48 |
| Wed 27 Feb | 279 | 36.7% | 4.5% | 4.7% | 52.1% | 48 |
| Thu 28 Feb | 289 | 33.2% | 5.9% | 1.3% | 55.3% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in February 2019. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Low (70–139 g): 86 hours, 13%
- Moderate (140–219 g): 242 hours, 37%
- High (220–299 g): 272 hours, 41%
- Very high (300 g or more): 58 hours, 9%
Records in February 2019
- Cleanest half hour
- 74 g 04:00 on Saturday 9 February
- Dirtiest half hour
- 342 g 06:00 on Tuesday 5 February
- Most wind
- 41.0% 23:30 on Sunday 17 February
- Most solar
- 20.5% 12:00 on Sunday 24 February
- Most low-carbon
- 72.8% 05:30 on Sunday 17 February
- Least gas
- 16.3% 23:30 on Sunday 17 February
- Cleanest day
- 120 g Sunday 17 February
- Dirtiest day
- 289 g Thursday 28 February
- Windiest day
- 34.2% wind Sunday 17 February
- Sunniest day
- 5.1% solar Sunday 24 February
About these figures
GridMonkey records NESO's carbon intensity and generation mix for Great Britain every half hour: the actual figure where NESO has published one, otherwise its forecast. They are added up by UK calendar day and month. Percentages are shares of the electricity generated, imports included, so the fuels add up to 100%. Low-carbon means wind, solar, nuclear, biomass and hydro. The carbon bands are GridMonkey's: very low under 70 g, low 70–139 g, moderate 140–219 g, high 220–299 g and very high 300 g or more, per kWh. Northern Ireland has its own grid and isn't included.
To see the grid now, open GridMonkey. For the wind farms that ran hardest this week, see the wind farm league table.
Data: NESO Carbon Intensity API (carbonintensity.org.uk), licensed under CC BY 4.0, recorded and summarised by GridMonkey. Figures as of 31 October 2026.