In April 2026, Britain's electricity averaged 94 gCO₂/kWh, in the low band (70–139 g). That is 20% cleaner than March 2026 (117 g), and 29% cleaner than April 2025 (133 g). Wind made 33.4% of the electricity generated, gas 17.7%, nuclear 17.7% and imports 12.5%; low-carbon sources together made 69.1%. The cleanest half hour was 20 g at 14:00 on Tuesday 7 April, and the dirtiest 201 g at 06:30 on Monday 13 April. The cleanest day was Thursday 30 April (46 g on average); the windiest was Saturday 11 April (60.0% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Wed 1 Apr | 158 | 52.5% | 25.6% | 2.2% | 35.7% | 48 |
| Thu 2 Apr | 125 | 62.4% | 26.2% | 10.3% | 27.5% | 48 |
| Fri 3 Apr | 58 | 83.4% | 59.0% | 3.6% | 11.5% | 48 |
| Sat 4 Apr | 66 | 76.7% | 48.7% | 5.8% | 11.4% | 48 |
| Sun 5 Apr | 51 | 83.7% | 53.2% | 10.2% | 8.3% | 48 |
| Mon 6 Apr | 77 | 67.2% | 29.0% | 14.3% | 12.5% | 48 |
| Tue 7 Apr | 57 | 78.9% | 45.3% | 11.9% | 9.6% | 48 |
| Wed 8 Apr | 116 | 61.6% | 23.1% | 12.9% | 24.3% | 48 |
| Thu 9 Apr | 85 | 72.7% | 40.3% | 6.6% | 15.7% | 48 |
| Fri 10 Apr | 89 | 72.6% | 39.6% | 10.0% | 18.3% | 48 |
| Sat 11 Apr | 53 | 86.0% | 60.0% | 8.2% | 10.7% | 48 |
| Sun 12 Apr | 77 | 79.4% | 50.4% | 8.8% | 17.1% | 48 |
| Mon 13 Apr | 158 | 50.5% | 16.3% | 10.1% | 37.6% | 48 |
| Tue 14 Apr | 137 | 60.8% | 28.0% | 7.3% | 30.9% | 48 |
| Wed 15 Apr | 76 | 79.3% | 52.4% | 5.0% | 15.4% | 48 |
| Thu 16 Apr | 98 | 72.9% | 41.4% | 8.3% | 20.1% | 48 |
| Fri 17 Apr | 85 | 75.2% | 43.9% | 6.2% | 16.4% | 48 |
| Sat 18 Apr | 85 | 73.9% | 34.3% | 11.6% | 16.7% | 48 |
| Sun 19 Apr | 104 | 64.5% | 20.5% | 13.7% | 18.6% | 48 |
| Mon 20 Apr | 132 | 58.0% | 17.9% | 11.1% | 27.7% | 48 |
| Tue 21 Apr | 72 | 79.0% | 40.8% | 11.4% | 11.8% | 48 |
| Wed 22 Apr | 62 | 79.0% | 37.0% | 13.7% | 8.5% | 48 |
| Thu 23 Apr | 98 | 62.7% | 17.2% | 14.6% | 15.9% | 48 |
| Fri 24 Apr | 134 | 53.0% | 6.0% | 15.1% | 23.2% | 48 |
| Sat 25 Apr | 118 | 55.1% | 8.2% | 15.5% | 19.2% | 48 |
| Sun 26 Apr | 109 | 58.3% | 13.6% | 12.8% | 17.6% | 48 |
| Mon 27 Apr | 144 | 51.7% | 10.0% | 12.1% | 27.7% | 48 |
| Tue 28 Apr | 86 | 66.3% | 29.5% | 8.0% | 11.3% | 48 |
| Wed 29 Apr | 53 | 76.4% | 38.4% | 13.6% | 5.1% | 48 |
| Thu 30 Apr | 46 | 80.7% | 47.3% | 13.0% | 5.9% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in April 2026, with April 2025 beneath it for comparison. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Very low (under 70 g): 259 hours, 36%
- Low (70–139 g): 317 hours, 44%
- Moderate (140–219 g): 145 hours, 20%
Records in April 2026
- Cleanest half hour
- 20 g 14:00 on Tuesday 7 April
- Dirtiest half hour
- 201 g 06:30 on Monday 13 April
- Most wind
- 68.4% 01:30 on Sunday 5 April
- Most solar
- 45.6% 13:00 on Saturday 25 April
- Most low-carbon
- 94.3% 14:30 on Tuesday 7 April
- Least gas
- 1.2% 14:30 on Wednesday 22 April
- Cleanest day
- 46 g Thursday 30 April
- Dirtiest day
- 158 g Wednesday 1 April
- Windiest day
- 60.0% wind Saturday 11 April
- Sunniest day
- 15.5% solar Saturday 25 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 18 October 2026.