In April 2024, Britain's electricity averaged 93 gCO₂/kWh, in the low band (70–139 g). That is 27% cleaner than March 2024 (128 g), and 42% cleaner than April 2023 (161 g). Wind made 37.0% of the electricity generated, gas 17.6%, nuclear 17.3% and imports 12.2%; low-carbon sources together made 69.3%. The cleanest half hour was 19 g at 13:30 on Monday 15 April, and the dirtiest 238 g at 20:30 on Friday 26 April. The cleanest day was Friday 5 April (39 g on average); the windiest was Saturday 6 April (61.2% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Mon 1 Apr | 92 | 64.7% | 32.7% | 5.4% | 17.9% | 48 |
| Tue 2 Apr | 133 | 52.9% | 24.3% | 4.3% | 28.3% | 48 |
| Wed 3 Apr | 75 | 69.8% | 43.1% | 3.0% | 14.9% | 48 |
| Thu 4 Apr | 114 | 58.1% | 27.5% | 4.0% | 25.2% | 48 |
| Fri 5 Apr | 39 | 81.6% | 53.7% | 5.2% | 6.4% | 48 |
| Sat 6 Apr | 40 | 86.5% | 61.2% | 5.2% | 8.3% | 48 |
| Sun 7 Apr | 48 | 86.6% | 61.2% | 5.9% | 7.7% | 48 |
| Mon 8 Apr | 116 | 61.7% | 32.6% | 4.2% | 24.8% | 48 |
| Tue 9 Apr | 48 | 81.6% | 50.9% | 4.2% | 7.3% | 48 |
| Wed 10 Apr | 67 | 77.0% | 46.9% | 3.0% | 11.3% | 48 |
| Thu 11 Apr | 67 | 79.4% | 46.9% | 4.8% | 11.5% | 48 |
| Fri 12 Apr | 48 | 84.8% | 51.0% | 6.7% | 7.5% | 48 |
| Sat 13 Apr | 52 | 84.2% | 50.2% | 6.7% | 8.3% | 48 |
| Sun 14 Apr | 65 | 79.6% | 44.9% | 8.1% | 10.6% | 48 |
| Mon 15 Apr | 42 | 86.1% | 56.6% | 6.6% | 6.4% | 48 |
| Tue 16 Apr | 56 | 81.1% | 47.5% | 6.8% | 9.3% | 48 |
| Wed 17 Apr | 108 | 67.4% | 31.4% | 7.0% | 20.2% | 48 |
| Thu 18 Apr | 96 | 68.9% | 33.8% | 6.7% | 17.9% | 48 |
| Fri 19 Apr | 54 | 78.1% | 48.1% | 6.0% | 9.0% | 48 |
| Sat 20 Apr | 81 | 67.3% | 25.9% | 9.4% | 13.0% | 48 |
| Sun 21 Apr | 105 | 62.2% | 21.3% | 8.6% | 18.2% | 48 |
| Mon 22 Apr | 191 | 43.8% | 10.3% | 3.6% | 42.1% | 48 |
| Tue 23 Apr | 143 | 56.4% | 22.7% | 5.5% | 30.9% | 48 |
| Wed 24 Apr | 129 | 60.6% | 25.3% | 6.3% | 25.2% | 48 |
| Thu 25 Apr | 176 | 50.8% | 18.6% | 4.5% | 37.1% | 48 |
| Fri 26 Apr | 197 | 42.8% | 7.1% | 6.6% | 40.7% | 48 |
| Sat 27 Apr | 156 | 51.7% | 16.7% | 4.6% | 28.6% | 48 |
| Sun 28 Apr | 91 | 66.7% | 36.2% | 5.8% | 14.6% | 48 |
| Mon 29 Apr | 77 | 74.4% | 42.8% | 6.2% | 12.8% | 48 |
| Tue 30 Apr | 72 | 72.6% | 37.5% | 7.7% | 12.2% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in April 2024, with April 2023 beneath it for comparison. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Very low (under 70 g): 338 hours, 47%
- Low (70–139 g): 216 hours, 30%
- Moderate (140–219 g): 161 hours, 22%
- High (220–299 g): 6 hours, 1%
Records in April 2024
- Cleanest half hour
- 19 g 13:30 on Monday 15 April
- Dirtiest half hour
- 238 g 20:30 on Friday 26 April
- Most wind
- 68.8% 03:00 on Sunday 7 April
- Most solar
- 26.5% 12:30 on Saturday 20 April
- Most low-carbon
- 94.9% 15:00 on Monday 15 April
- Least gas
- 0.0% 23:00 on Saturday 13 April
- Cleanest day
- 39 g Friday 5 April
- Dirtiest day
- 197 g Friday 26 April
- Windiest day
- 61.2% wind Saturday 6 April
- Sunniest day
- 9.4% solar Saturday 20 April
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 22 October 2026.