NESO September 2026: 68% zero-carbon power, wind 36%, gas 20.5%
Victoria Shinder2 min readThe National Energy System Operator (NESO) published its monthly Britain's Energy Explained report for September 2026 on 9 October. The headline numbers for Great Britain's electricity system:
- 68% of electricity came from zero-carbon sources over the month, with a peak zero-carbon share of 95%.
- Average carbon intensity: 108 gCO2/kWh; the lowest half-hour reached 27 gCO2/kWh. The greenest moment of the month was 13:30 on 12 September.
- 22 TWh ran through the network. Peak demand came at 18:00 on 28 September.
Generation mix, September 2026 (share of supply as NESO reports it):
| source | share | |---|---| | Wind | 36.3% | | Gas | 20.5% | | Nuclear | 12.2% | | Imports | 10.8% | | Biomass | 8.2% | | Solar | 8.2% | | Storage | 2.2% | | Hydro | 1.8% |
Interconnectors. NESO puts electricity flowing in from interconnectors at 2,435 GWh and flowing out at 1,520 GWh for the month — Britain was a net importer in September, with imports covering more than a tenth of supply.
Gas. On the gas side, NESO reports 86% of supply entering from UK and Norwegian fields, 5% from LNG and 9% from storage withdrawal, with distribution networks taking 42% of gas, EU and Ireland exports 27% and power stations 23%. NESO flags that gas figures are not yet reconciled and points to National Gas's data portal for the latest.
How to read it. September is a shoulder month: solar is still meaningful at 8.2% while wind is already carrying more than a third of supply, which is why a 95% zero-carbon peak and a 108 g average sit together — the system is very clean in windy, sunny hours and still leans on gas, at one-fifth of supply, in the evening peak. The report also shows month-on-month changes for each source; NESO's live figures are available through its app and at carbonintensity.org.uk.
Source: NESO, "Britain's Energy Explained: September 2026", 9 October 2026 — https://www.neso.energy/september-2026-energy-report