- Renewables have so far accounted for 100% of mainland Britain’s electricity demand for 87 hours in 2025, an increase of 97.1% on 2021
- The longest period of 100% renewable energy generation was 15 hours in May
- The government wants 95% of all energy generation to be renewable by 2030

Clean energy has been responsible for 100% of all mainland Britain’s electricity demand for a record 87 hours so far this year, according to data from Carbon Brief.
This figure is up by 25.8% on the 64.5 hours in 2024 and 97.1% from the 2.5 hours in 2021.
According to Carbon Brief’s analysis, during the periods where clean energy accounted for all of mainland Britain’s demand, the biggest source was wind, which pitched in 72% of power, followed by nuclear at 18% and solar at 10%.
When you include biomass at 4% and hydro at 1%, clean energy has at times generated 105% of national demand in 2025. The most recent period when mainland Britain had all its electricity provided by clean energy was on Friday 12 September between 2am and 6am.
Northern Ireland, which is part of the separate all-Ireland grid, is not included in the data.
For more information on government grants for solar panels, have a look at our dedicated guide.
The longest period where clean energy has provided 100% of mainland Britain’s energy is from midnight on 25 May to 3pm on 26 May at a total of 15 hours.
During the periods when renewable energy was offering 100% of electricity, the country was still generating energy from gas, enough to potentially meet 13% of mainland Britain’s demand.

Get free solar panel quotes
Answer a few quick questions, and our trusted installers will send you bespoke solar panel quotes – for free.
Combined with the surplus of clean energy, this meant the country could export 19% of the total energy it generated across all sources, and it did so to Ireland, France, Belgium, Denmark, Norway and the Netherlands.
Government clean energy targets
The data shows the UK government is closer to reach its goal of having 95% of electricity demand covered by clean energy sources by 2030 and for 100% to be met without fossil fuels.
In 2025 so far, 66% of electricity has come from either renewable sources of nuclear, which accounted for 59% of total demand, the difference being down to net imports.
On top of that, the National Energy System Operator (NESO) has its own goal of running the electricity grid without fossil fuels for at least 30 minutes by the end of 2025.
Craig Dyke, NESO’s director of system operations, told Carbon Brief that he expects the first 30 minutes of full zero-carbon electricity could be achieved this autumn, describing it as “absolutely groundbreaking”.

Get £7,500 towards your heat pump installation through a trusted installer
An MCS-certified heat pump installer can apply for the Boiler Upgrade Scheme on your behalf. Get a quote from one now