In July 2024, Britain's electricity averaged 115 gCO₂/kWh, in the low band (70–139 g). That is 15% dirtier than June 2024 (100 g), and 20% cleaner than July 2023 (143 g). Gas made 25.4% of the electricity generated, wind 22.6%, nuclear 17.9% and imports 16.4%; low-carbon sources together made 58.1%. The cleanest half hour was 28 g at 14:30 on Thursday 4 July, and the dirtiest 230 g at 20:30 on Monday 8 July. Thursday 4 July was both the cleanest day (50 g on average) and the windiest (55.7% wind).
Carbon intensity, day by day
Day by day, as a table
| Day | gCO₂/kWh | Low-carbon | Wind | Solar | Gas | Half hours |
|---|---|---|---|---|---|---|
| Mon 1 Jul | 91 | 61.5% | 26.8% | 5.8% | 19.7% | 48 |
| Tue 2 Jul | 104 | 64.7% | 27.6% | 7.2% | 22.0% | 48 |
| Wed 3 Jul | 90 | 72.0% | 37.1% | 5.5% | 17.3% | 48 |
| Thu 4 Jul | 50 | 86.7% | 55.7% | 9.3% | 10.6% | 48 |
| Fri 5 Jul | 81 | 70.8% | 36.8% | 7.2% | 18.6% | 48 |
| Sat 6 Jul | 55 | 68.6% | 31.7% | 8.9% | 11.1% | 48 |
| Sun 7 Jul | 82 | 60.6% | 22.5% | 10.1% | 18.6% | 48 |
| Mon 8 Jul | 170 | 41.1% | 7.2% | 7.7% | 39.9% | 48 |
| Tue 9 Jul | 91 | 63.8% | 35.2% | 3.5% | 21.5% | 48 |
| Wed 10 Jul | 86 | 66.4% | 35.9% | 6.4% | 19.2% | 48 |
| Thu 11 Jul | 149 | 49.4% | 16.7% | 7.9% | 36.3% | 48 |
| Fri 12 Jul | 119 | 56.3% | 23.2% | 6.3% | 28.1% | 48 |
| Sat 13 Jul | 85 | 64.5% | 27.9% | 7.5% | 19.6% | 48 |
| Sun 14 Jul | 83 | 62.1% | 24.7% | 8.7% | 18.3% | 48 |
| Mon 15 Jul | 165 | 42.2% | 7.6% | 5.3% | 38.0% | 48 |
| Tue 16 Jul | 133 | 53.8% | 19.6% | 6.4% | 29.4% | 48 |
| Wed 17 Jul | 156 | 50.3% | 11.7% | 10.1% | 34.6% | 48 |
| Thu 18 Jul | 120 | 59.1% | 22.1% | 9.9% | 26.6% | 48 |
| Fri 19 Jul | 105 | 64.6% | 28.5% | 11.0% | 20.8% | 48 |
| Sat 20 Jul | 130 | 52.7% | 18.5% | 6.3% | 25.8% | 48 |
| Sun 21 Jul | 105 | 57.5% | 20.7% | 9.8% | 20.3% | 48 |
| Mon 22 Jul | 128 | 53.3% | 19.9% | 6.9% | 27.5% | 48 |
| Tue 23 Jul | 158 | 45.8% | 10.8% | 8.3% | 36.0% | 48 |
| Wed 24 Jul | 154 | 49.4% | 17.2% | 6.6% | 35.2% | 48 |
| Thu 25 Jul | 110 | 60.7% | 31.9% | 4.1% | 24.0% | 48 |
| Fri 26 Jul | 119 | 57.1% | 20.7% | 10.0% | 25.4% | 48 |
| Sat 27 Jul | 153 | 45.1% | 6.2% | 10.4% | 34.6% | 48 |
| Sun 28 Jul | 107 | 57.3% | 10.0% | 13.8% | 22.6% | 48 |
| Mon 29 Jul | 98 | 61.1% | 20.8% | 11.5% | 21.7% | 48 |
| Tue 30 Jul | 136 | 52.9% | 13.9% | 10.8% | 30.6% | 48 |
| Wed 31 Jul | 153 | 48.8% | 10.9% | 10.3% | 34.6% | 48 |
What powered the grid
Each fuel's average share of the electricity generated in Great Britain in July 2024, with July 2023 beneath it for comparison. Imports count as one source, as NESO counts them.
Hours in each carbon band
- Very low (under 70 g): 136 hours, 18%
- Low (70–139 g): 390 hours, 52%
- Moderate (140–219 g): 216 hours, 29%
- High (220–299 g): 2 hours, 0%
Records in July 2024
- Cleanest half hour
- 28 g 14:30 on Thursday 4 July
- Dirtiest half hour
- 230 g 20:30 on Monday 8 July
- Most wind
- 64.2% 01:00 on Thursday 4 July
- Most solar
- 37.4% 12:30 on Sunday 28 July
- Most low-carbon
- 91.7% 14:30 on Thursday 4 July
- Least gas
- 5.4% 14:30 on Thursday 4 July
- Cleanest day
- 50 g Thursday 4 July
- Dirtiest day
- 170 g Monday 8 July
- Windiest day
- 55.7% wind Thursday 4 July
- Sunniest day
- 13.8% solar Sunday 28 July
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.