The government body tasked with keeping the lights on issued a rare call for more electricity supplies on Monday morning due to low wind power generation forecasts across Europe.
A notice issued by the National Energy System Operator (Neso) on Sunday night said it faced a “shortfall†of almost 1,400 megawatts in its electricity supply margins from 6am until 11am on Monday.
The notice said Neso would need to find extra generation of about 800 megawatts, or the equivalent of a medium-sized gas power plant, within eight hours before a review of power supplies scheduled for 4am.
A second “electricity margin notice†issued after the pre-dawn review revealed that Neso's 11th-hour margin call helped to shrink its shortfall to 500MW. It said that no further contingency power was required but Neso could still call on power plants to generate more than usual between 8am and 11am.
A later update said the shortfall had shrunk again, to 200MW, before being cancelled entirely just after 9am.
In the past, these notices would typically have been used during cold, winter evenings, when electricity use is often at its highest for the year, to call for extra power supplies to meet the peak in demand.
The unusual morning power shortfall has followed an uptick in Neso alerts over recent months, including the first margin notices to be issued during this summer when heatwaves pushed demand higher while curbing generation.
A spokesperson for Neso, which balances the power system's supply and demand on a minute-by-minute basis around the clock, said the notice was “a routine and precautionary measure†to give the market “an opportunity†to make extra generation capacity available.
“This is not a warning of power cuts, there is no risk to customer electricity supplies, and customers do not need to take action – Great Britain's electricity system remains secure,†the spokesperson said.
The market notice was issued despite there being no constraints within the electricity grid which might make power plants or windfarms unavailable, and while the UK is forecast to export electricity to Europe.
This suggests that the shortfall may have been prompted by low wind speeds across Europe, which have curbed the continent's renewable energy output at the end of last week.
In northern Europe, periods with a reduction in solar and wind power are referred to as Dunkelflaute, German for “dark doldrumsâ€, in the renewable energy sector.
On Friday, Neso paid more than 10 times the market price of earlier in the week to secure power imports from Europe, which will ultimately be covered through charges on home energy bills.
Kathryn Porter, an independent energy consultant, said these payments included £2,500 a megawatt-hour for power imported via Great Britain's high voltage subsea cables, and £1,000/MWh to fire up gas plants.
The system operator is under scrutiny after an independent investigation, published last month, found significant and concerning “cultural issues†within the grid operator's control room.
The three-month investigation was undertaken by an external law firm after whistleblowers accused Neso of covering up the growing risk of blackouts faced by the country.
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After a string of margin notices over the summer, the whistleblowers claimed the grid was becoming increasingly unmanageable, and that control room decisions were subject to “interference†by the company's corporate affairs team to protect the reputation of the government-owned operator.
Neso was once part of the FTSE 100 energy company National Grid. It came back under government control in 2024.
Separately on Monday, benchmark Dutch and British wholesale gas prices rose amid colder weather forecasts, increasing demand for heating.
The benchmark Dutch month-ahead contract edged up by €0.91 to €86.50 (£72) a MWh, ICE data showed. The equivalent British contract rose by 2.75 pence to 215p a therm.
Wholesale energy prices remain in focus as markets closely watch developments in the Middle East conflict.
The LSEG gas analyst Yuriy Onyshkiv said: “News is mixed. Trump downplayed the likelihood of further US strikes on Iran while talks progress, which eases geopolitical risk. However, both sides reported shipping hit in or near the strait of Hormuz.
The US president, Donald Trump, said on Sunday he was highly unlikely to order fresh attacks on Iran as long as talks to end the conflict progressed. The Brent crude oil price fell 0.6% to just under $96 (£72)a barrel on Monday.
The AA said petrol prices had peaked at 174.7p a litre earlier this month to reach their highest since August 2022 but started this week at 169.7p.
