Electricity grid operators across Europe are preparing for a temporary drop in solar power generation during Wednesday’s solar eclipse, while UK households are being encouraged to reduce their electricity use as the Moon passes in front of the Sun.
The eclipse on 12th August is expected to cause a rapid but predictable fall in photovoltaic generation across Europe. The European Network of Transmission System Operators for Electricity (ENTSO-E) estimates that solar output could drop by as much as 9.7 gigawatts under clear-sky conditions between 19:15 and 21:30 CEST.
Transmission system operators (TSOs) have been coordinating preparations to maintain the stability of electricity networks during the event. Control room staff have been briefed, while market participants have been warned about the expected reduction in solar generation.
Spain and Germany are expected to experience some of the largest reductions in photovoltaic output. TSOs are also receiving updated solar generation forecasts from weather services to help operators make decisions in real time.
Planned grid outages are being avoided during the eclipse to maximise flexibility, while ENTSO-E has established a dedicated task force to coordinate preparations and monitor the impact across Europe.
Solar power accounted for around 13% of EU electricity generation in 2025, meaning sudden changes in output are becoming increasingly important for grid operators as renewable generation expands.
Never ones to miss a trick, Octopus Energy is asking customers to reduce their electricity consumption between 6pm and 8pm in the UK, where the eclipse is expected to block up to 95% of the Sun in some areas.
In return, the company is offering eligible customers free electricity the following weekend if they use less power than usual during the two-hour period. Customers can also enter a competition to win solar panels and installation, or a £12,000 cash alternative.
Households are being encouraged to move activities such as running washing machines, dishwashers and games consoles outside the peak eclipse period.
The timing is significant because the reduction in solar generation is expected to coincide with rising evening electricity demand as people return home.
Solar power produced a record 14.4% of Britain’s electricity in July, according to Octopus, increasing the importance of managing short-term changes in solar output.
Rebecca Dibb-Simkin, Chief Customer Officer at Octopus Energy, said: ‘Many of us will be looking up at the sky on Wednesday evening to experience this once-in-a-generation event. But as the Sun disappears, so will some of Britain’s solar generation, just as demand peaks.
‘By shifting everyday tasks like the washing machine or dishwasher until later, households can help reduce the need for gas power stations – and earn rewards for doing their bit.’
Photo: Jongsun Lee