Wind power became the largest source of UK electricity generation in 2024, with today’s blackout warning from the system operator bringing the grid-balancing act into sharp focus.
The National Electricity System Operator (NESO) issued a system warning of a 1,700 MW (1.7 GW) “shortfall” in power that, it warned, could lead to blackouts.
“An electricity margin notice (EMN) has been issued to the market,” NESO said in a statement. “Our forecasts are showing tight margins on the electricity system for today between 16:00-19:00.
“This is a routine tool that we use most winters, and means we are asking market participants to make any additional generation capacity they may have available.
“The EMN does not mean electricity supply is at risk.”
‘Outages’
The warning followed interconnector grid outages affecting imports of electricity from certain countries in Europe.
The network operator indicated that outages had affected imports of electricity from some European countries through interconnectors in France (ElecLink) and the Netherlands.
The GreenLink interconnector in Ireland, while not yet commissioned, could bring extra power including electricity produced from offshore wind.
Shivam Malhotra, head of power trading at LCP Delta, said that “high energy demand clashes with periods of dwindling low wind output”, adding that the warning notice from NESO provides strong signal to the market to “respond”.
“Wind power is forecast to drop to just 1.6-2.6 GW late afternoon and early evening, while demand is expected to peak at 46.5 GW,” said Malhotra.
“This leaves the NESO with a thin margin of only 510 MW at 17:00, with a current loss of load probability of 29%, which is the chance of power shortages or ‘load shedding,’ where electricity supply may need to be restricted in certain areas. This is very unlikely to happen, and this number will likely drop later in the day as the market reacts to the notice.”
Malhotra said NESO’s options for meeting demand remain “relatively limited” as the UK is already importing 5 GW from interconnectors.
“One option here could be returning some interconnection from outage, such as the 1GW ElecLink GB-France interconnector,” he added.
“The majority of the UK’s thermal power plants are running at full capacity already so cannot add further support, with some being accepted to remain on for £3,400/MWh in the Balancing Mechanism to ensure they can deliver power during this tight period.”
A total of £5.8 million (£5,839k) was spent on balancing costs in the last day, according to the network operator. Peak demand yesterday hit 46,738 MW.
© Mathew Perry/DCT MediaWind ‘takes over from gas’
NESO said yesterday that the grid had record low carbon-intensity and reached a new record for wind power in 2024. Just 125 grams of carbon dioxide were produced per kilowatt-hour of electricity on the system on average, it said.
Posting on social media platform Bluesky, Energy Minister Michael Shanks said: “An incredible transformation in our energy mix – wind power takes over from gas as our biggest source of electricity.”
Wind power accounted for nearly a third of electricity last year, hitting a record of more than 22.5 GW on a single day in December, while renewable electricity made up more than half the UK’s electricity supply.
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