European electricity prices surge as heatwave lifts demand and cuts supply

Europe’s heatwave is pushing wholesale electricity prices sharply higher across major markets as demand for cooling rises and supply is constrained by weak wind, heat-limited gas units and cooling issues at some French nuclear reactors.

In Great Britain, the system is paying about £470 per megawatt-hour for imported electricity during the 5 p.m. to 7 p.m. peak window, according to the reporting cited by The Guardian. That is more than six times the June 2025 average of about £71/MWh and more than three times Monday’s £123/MWh level.

The price spike is part of a broader squeeze across Europe rather than a single-country event. German power prices were forecast above €545/MWh, the highest since June 2024, according to Epex Spot. French wholesale electricity prices climbed above €268/MWh, the highest since August 2023.

Heatwave pressure builds

The latest jump follows days of severe heat across France, Britain and parts of continental Europe. Le Monde said France’s heatwave began on June 17 and could last into the weekend of June 27-28 or even into early July.

That same heat has become a direct energy-market problem. As temperatures rise, households, offices and industry use more electricity for cooling at the same time that several forms of generation become less flexible or less efficient.

France has also recorded extreme temperatures during the episode, adding to the strain on infrastructure and public services. The Guardian and Le Monde both reported broad disruption across the country as the hot spell intensified.

Supply-side constraints

The supply picture has tightened on several fronts at once. The Guardian reported that UK wind power supplied about 13% to 15% of electricity on Tuesday, down from around 30% in June 2025. Lower wind output removes an important source of flexible generation just as demand is climbing.

Britain has also seen heat-related deratings at gas plants. The Guardian said five British gas plants reduced output because of ambient heat conditions, removing about 2.5 gigawatts of capacity.

France is dealing with another heat-linked constraint. Lower river-water temperatures are making it harder to cool some nuclear reactors, according to The Guardian. That leaves a major power system under pressure at the same time that electricity demand remains elevated.

Demand rises with the temperature

The demand side is moving in the opposite direction from supply. The hotter it gets, the more power consumers need for cooling, especially during the evening peak when systems are already stretched.

UK households are being asked to reduce consumption during peak hours through a demand-reduction scheme that can save about 115 megawatts, according to The Guardian. The measure is small relative to total system demand, but it shows how operators are trying to shave the highest-risk hours.

That balance matters because peak demand is arriving when imports are expensive and domestic generation is constrained. The result is a sharp move in wholesale prices across multiple markets at once.

Why the spike matters

Higher wholesale power prices can eventually feed through to balancing costs and, over time, consumer bills. The episode also raises reliability risks if heat-related outages deepen or if low wind output persists.

The current market stress illustrates how climate extremes can hit energy systems on both sides of the ledger at once. Demand rises when people need more cooling, while supply can fall when wind weakens or thermal and nuclear plants face operating limits.

France, Britain and Germany are all seeing heat-related power-system strain at the same time, broadening the impact beyond one national grid. That makes the episode a regional energy story, not just a weather story.

What to watch next

The key near-term question is whether prices stay elevated into the next market day or ease if wind speeds recover and temperatures fall. Traders and system operators will also be watching for further plant deratings, new outage notices or signs that demand-response measures are working.

Additional attention is likely to fall on British gas units and French nuclear output, since both have already shown heat-related constraints. Any change in those conditions could quickly alter the pricing picture.

For now, Europe’s heatwave is feeding directly into power markets. The combination of higher cooling demand, weaker wind and constrained generation has turned an extreme-weather event into a market-moving energy shock.