Britain’s grid operator has sent out a fresh warning regarding power supplies after soaring temperatures piled strain on energy networks.
The National Energy System Operator (Neso) issued an Electricity Margin Notice for Thursday evening, encouraging power plants to provide extra supplies to cope with “extreme temperatures”.
The notice is the third of its kind this summer, highlighting the increased pressure on the grid as households turn on fans and air conditioners.
Neso warned of a potential shortfall of 1.2 gigawatts (GW) in capacity between 6.30pm and 10.30pm on Thursday night, roughly equating to the output of one of the UK’s five nuclear power stations.
It comes as temperatures are forecast to hit 36C in some parts of the country, while wind speeds plummet.
By midday on Thursday, the UK’s total wind output had fallen to 1.5GW, compared with 10-12GW on a windy day.
Gas-fired power stations can make up some of the difference, but closures and maintenance schedules mean the UK is also heavily reliant on imports via interconnector cables.
About 22pc of the UK’s electricity was being generated overseas on Thursday morning, of which just more than half was coming from France.
‘Tight electricity margins’
Electricity margin notices are aimed at encouraging generators to make any extra capacity available, with the prospect of being paid premium rates to do so.
Neso said the notices do not signal imminent blackouts or that there is not enough generation to meet demand.
Margin notices have only previously been needed in winter, when demand for heating and lighting surges.
However, as the UK becomes increasingly reliant on weather-dependent renewables, such as wind and solar, extra capacity is essential in summer as well.
A Neso spokesman said: “Our forecasts indicate tight electricity margins. This is due to extreme temperatures across Europe, reducing the availability of some generation.”
Kathryn Porter, an energy analyst, said policy makers were increasingly gambling on the weather and on other countries to keep Britain’s lights on.
“This is only going to get worse,” she said. “High pressure weather systems with lots of sun but little wind are common both in summer when they cause high temperatures and winter when they bring the coldest temperatures.
“Clearly we’re struggling to manage. We need sensible energy policies and to stop gambling on the weather and praying other countries can bail us out.”
The heat is expected to peak on Thursday and Friday when temperatures will “widely exceed 30C” across the UK, according to the Met Office.
