In August 2024, Britain's electricity averaged 84 gCO₂/kWh, in the low band (70–139 g). That is 27% cleaner than July 2024 (115 g), and 48% cleaner than August 2023 (161 g). Wind made 33.4% of the electricity generated, nuclear 19.7%, gas 17.5% and imports 12.3%; low-carbon sources together made 70.0%. The cleanest half hour was 25 g at 11:30 on Friday 23 August, and the dirtiest 220 g at 21:00 on Thursday 29 August. Sunday 25 August was both the cleanest day (49 g on average) and the windiest (53.9% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Thu 1 Aug | 166 | 46.3% | 8.9% | 9.0% | 37.2% | 48 |
| Fri 2 Aug | 105 | 60.7% | 25.0% | 8.1% | 21.9% | 48 |
| Sat 3 Aug | 100 | 59.3% | 19.8% | 9.7% | 20.2% | 48 |
| Sun 4 Aug | 72 | 67.2% | 27.1% | 7.8% | 13.2% | 48 |
| Mon 5 Aug | 73 | 73.2% | 40.8% | 5.6% | 15.5% | 48 |
| Tue 6 Aug | 87 | 66.4% | 28.0% | 7.8% | 17.3% | 48 |
| Wed 7 Aug | 58 | 73.4% | 40.5% | 5.7% | 12.2% | 48 |
| Thu 8 Aug | 71 | 69.0% | 37.9% | 4.2% | 15.9% | 48 |
| Fri 9 Aug | 53 | 85.0% | 51.6% | 8.9% | 10.9% | 48 |
| Sat 10 Aug | 67 | 75.0% | 38.6% | 7.1% | 13.7% | 48 |
| Sun 11 Aug | 77 | 67.3% | 19.7% | 12.3% | 12.9% | 48 |
| Mon 12 Aug | 73 | 77.1% | 39.8% | 7.8% | 13.5% | 48 |
| Tue 13 Aug | 94 | 67.6% | 26.5% | 7.9% | 18.7% | 48 |
| Wed 14 Aug | 131 | 56.4% | 16.7% | 7.1% | 29.5% | 48 |
| Thu 15 Aug | 63 | 75.2% | 41.2% | 5.2% | 12.4% | 48 |
| Fri 16 Aug | 94 | 68.1% | 25.3% | 9.8% | 19.7% | 48 |
| Sat 17 Aug | 86 | 69.4% | 24.2% | 8.7% | 17.1% | 48 |
| Sun 18 Aug | 69 | 71.1% | 30.5% | 9.2% | 14.5% | 48 |
| Mon 19 Aug | 78 | 69.2% | 34.5% | 4.0% | 15.8% | 48 |
| Tue 20 Aug | 50 | 81.0% | 46.8% | 8.5% | 10.4% | 48 |
| Wed 21 Aug | 58 | 82.4% | 52.7% | 6.0% | 12.9% | 48 |
| Thu 22 Aug | 62 | 80.4% | 51.0% | 4.3% | 13.7% | 48 |
| Fri 23 Aug | 55 | 80.7% | 45.0% | 8.9% | 11.6% | 48 |
| Sat 24 Aug | 54 | 75.3% | 39.2% | 6.5% | 10.4% | 48 |
| Sun 25 Aug | 49 | 86.1% | 53.9% | 6.7% | 10.0% | 48 |
| Mon 26 Aug | 79 | 74.2% | 37.8% | 8.3% | 16.9% | 48 |
| Tue 27 Aug | 93 | 72.9% | 40.9% | 5.2% | 20.1% | 48 |
| Wed 28 Aug | 128 | 60.7% | 25.5% | 5.8% | 25.9% | 48 |
| Thu 29 Aug | 136 | 59.5% | 23.0% | 8.8% | 28.8% | 48 |
| Fri 30 Aug | 152 | 51.8% | 12.9% | 9.2% | 34.8% | 48 |
| Sat 31 Aug | 71 | 67.4% | 30.9% | 7.3% | 15.1% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in August 2024, with August 2023 beneath it for comparison. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Very low (under 70 g): 363 hours, 49%
- Low (70–139 g): 283 hours, 38%
- Moderate (140–219 g): 98 hours, 13%
- High (220–299 g): 1 hours, 0%
Records in August 2024
- Cleanest half hour
- 25 g 11:30 on Friday 23 August
- Dirtiest half hour
- 220 g 21:00 on Thursday 29 August
- Most wind
- 66.7% 02:30 on Friday 9 August
- Most solar
- 35.2% 13:00 on Sunday 11 August
- Most low-carbon
- 91.9% 13:00 on Friday 9 August
- Least gas
- 4.6% 13:00 on Thursday 15 August
- Cleanest day
- 49 g Sunday 25 August
- Dirtiest day
- 166 g Thursday 1 August
- Windiest day
- 53.9% wind Sunday 25 August
- Sunniest day
- 12.3% solar Sunday 11 August
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.