Turbines waste enough wind power to supply all of London’s homes

Britain’s wind farm turbines wasted enough energy to power all of London’s homes last year, new figures show.

A record 10 terawatt hours (TWh) of wind power went to waste in 2025, according to a report from energy analyst Montel – costing billpayers a total of £1.4bn in “curtailment costs”.

This was up 22pc on the year before, as growing strain on the grid prevented wind power from being transported to the cities and towns that need it most.

This results in so-called curtailment costs, which are paid to wind farms when they are asked to switch off.

At the same time, grid operators must call on gas plants to step in and keep the lights on with replacement power, often at great expense.

Analysts said that wind farms in Scotland were largely to blame.

Montel’s report said: “The amount of renewable electricity curtailed in Great Britain in 2025 (10TWh) could have met the combined electricity demand of every domestic household in London for the entire year.

“Northern Scotland has seen the most curtailment by far. Over 8.8TWh of wind power in northern Scotland was switched off, enough to also power all Scottish domestic electricity demand for the year.”

The cost of curtailment has been growing as Ed Miliband, the Energy Secretary, rolls out more renewable energy sources – such as wind and solar.

As well as paying wind developers, Montel said solar farms are also being asked to switch off because of bottlenecks.

Montel said: “Solar curtailment costs rose over the year to total over £252,000. While this is substantially lower than the corresponding figures for wind, it represents a rise from the negligible costs associated with solar curtailment in 2024.”

To combat curtailment, regulator Ofgem has approved plans for the UK’s three transmission operators – National Grid, Scottish Power and SSE – to spend up to £90bn on new lines and substations.

However, these will take at least five years to build, with constraint payments set to continue rising.

Octopus Energy has warned that such payments could see £8bn added to bills by 2030.

Claire Coutinho, the shadow energy secretary, has blamed Mr Miliband’s planned expansion of renewables for the recent uptick in costs.

The Energy Secretary has approved large numbers of new wind and solar projects as part of his plan to decarbonise the grid by 2030.

She said: “We are paying more than ever before to pay wind farms to switch off when the wind blows.

“Costs are set to triple by 2030 as he approves more wind farms than ever before. He cares far more about his own Clean Power 2030 target than looking after consumers.”

A spokesman for SSE said: “ The UK has built renewables where the resources are strongest, and now we need to upgrade the grid to eliminate bottlenecks so we can harness more of that energy, more of the time.”

The National Energy System Operator said it was working to keep energy costs down but stressed that grid expansion was crucial.

A spokesman said: “Without the crucial expansion of the electricity network by those who own it, and industry working together to deliver the changes needed, there is a risk that curtailment costs will continue to rise.”

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