In October 2024, Britain's electricity averaged 138 gCO₂/kWh, in the low band (70–139 g). That is 13% dirtier than September 2024 (122 g), and about the same as October 2023 (139 g). Wind made 32.4% of the electricity generated, gas 29.2%, nuclear 13.9% and imports 11.5%; low-carbon sources together made 59.3%. The cleanest half hour was 34 g at 14:30 on Saturday 5 October, and the dirtiest 254 g at 19:30 on Sunday 13 October. The cleanest day was Saturday 5 October (65 g on average); the windiest was Sunday 20 October (57.6% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Tue 1 Oct | 94 | 69.3% | 45.0% | 2.0% | 19.2% | 48 |
| Wed 2 Oct | 118 | 63.9% | 36.7% | 3.0% | 25.7% | 48 |
| Thu 3 Oct | 163 | 51.0% | 19.7% | 6.0% | 34.1% | 48 |
| Fri 4 Oct | 127 | 61.8% | 31.0% | 5.1% | 26.7% | 48 |
| Sat 5 Oct | 65 | 75.7% | 41.7% | 6.5% | 11.2% | 48 |
| Sun 6 Oct | 82 | 70.2% | 45.5% | 1.8% | 16.7% | 48 |
| Mon 7 Oct | 137 | 57.1% | 26.9% | 4.8% | 28.8% | 48 |
| Tue 8 Oct | 130 | 58.7% | 29.7% | 2.8% | 26.9% | 48 |
| Wed 9 Oct | 107 | 64.9% | 39.1% | 2.4% | 22.7% | 48 |
| Thu 10 Oct | 122 | 61.8% | 35.3% | 4.3% | 25.3% | 48 |
| Fri 11 Oct | 152 | 55.0% | 27.0% | 5.7% | 32.2% | 48 |
| Sat 12 Oct | 83 | 71.3% | 49.6% | 3.5% | 14.4% | 48 |
| Sun 13 Oct | 163 | 52.8% | 27.5% | 2.9% | 34.4% | 48 |
| Mon 14 Oct | 218 | 41.6% | 14.9% | 2.6% | 48.5% | 48 |
| Tue 15 Oct | 127 | 64.5% | 40.9% | 1.3% | 27.7% | 48 |
| Wed 16 Oct | 129 | 64.3% | 41.3% | 1.2% | 28.1% | 48 |
| Thu 17 Oct | 165 | 56.2% | 25.4% | 4.6% | 34.3% | 48 |
| Fri 18 Oct | 147 | 60.9% | 33.2% | 3.6% | 32.3% | 48 |
| Sat 19 Oct | 132 | 62.6% | 29.8% | 4.8% | 27.6% | 48 |
| Sun 20 Oct | 78 | 77.4% | 57.6% | 2.0% | 16.4% | 48 |
| Mon 21 Oct | 114 | 71.3% | 48.5% | 1.8% | 24.8% | 48 |
| Tue 22 Oct | 156 | 59.2% | 31.3% | 3.8% | 32.6% | 48 |
| Wed 23 Oct | 169 | 56.0% | 29.2% | 3.2% | 36.4% | 48 |
| Thu 24 Oct | 121 | 68.1% | 43.6% | 3.3% | 23.8% | 48 |
| Fri 25 Oct | 202 | 42.2% | 14.8% | 1.7% | 43.5% | 48 |
| Sat 26 Oct | 150 | 52.2% | 24.8% | 3.4% | 30.9% | 48 |
| Sun 27 Oct | 103 | 63.9% | 34.5% | 5.1% | 18.9% | 50 |
| Mon 28 Oct | 155 | 53.6% | 30.1% | 1.4% | 33.8% | 48 |
| Tue 29 Oct | 208 | 38.6% | 12.9% | 1.8% | 46.9% | 48 |
| Wed 30 Oct | 217 | 36.8% | 10.1% | 1.3% | 49.0% | 48 |
| Thu 31 Oct | 149 | 54.7% | 28.5% | 2.1% | 32.3% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in October 2024, with October 2023 beneath it for comparison. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Very low (under 70 g): 89 hours, 12%
- Low (70–139 g): 308 hours, 41%
- Moderate (140–219 g): 277 hours, 37%
- High (220–299 g): 72 hours, 10%
Records in October 2024
- Cleanest half hour
- 34 g 14:30 on Saturday 5 October
- Dirtiest half hour
- 254 g 19:30 on Sunday 13 October
- Most wind
- 68.5% 00:00 on Sunday 13 October
- Most solar
- 23.7% 12:00 on Saturday 5 October
- Most low-carbon
- 86.2% 00:00 on Sunday 13 October
- Least gas
- 3.5% 14:00 on Saturday 5 October
- Cleanest day
- 65 g Saturday 5 October
- Dirtiest day
- 218 g Monday 14 October
- Windiest day
- 57.6% wind Sunday 20 October
- Sunniest day
- 6.5% solar Saturday 5 October
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 21 October 2026.