Third heatwave of the summer.
The grid is getting tired.
Britain's power system was designed around a simple assumption: winter is the hard bit. Cold, dark, teatime, everyone home. Summer was the easy season. Three heatwaves in, that assumption is quietly falling apart, and this week is going to test it.
🧯 Summer was supposed to be the holiday
Power systems are built around their worst day. In Britain, that has always been a cold, still, dark evening in January.
Maintenance gets scheduled for summer. Plants come offline. Engineers take their leave. The whole industry exhales.
That works right up until summer stops being quiet. Record temperatures push cooling demand up at exactly the moment half the fleet is in bits on a workshop floor.
🌬️ Heat and wind do not get along
A heatwave in Britain usually means a big blocking high pressure system parked over the country. Blue skies. And, critically, almost no wind.
So the fleet that has been carrying an increasing share of the grid goes quiet exactly when demand climbs. Solar covers the middle of the day beautifully. Solar does nothing at 8pm, when it is still 28 degrees.
That leaves gas, nuclear and imports to cover a hot evening on their own. Which is fine, until it is not.
🇫🇷 And the neighbours have their own problems
Britain leans on cables to France and the continent to fill gaps. That works when the continent has spare power.
In a European heatwave the continent is in the same trouble, at the same hour, for the same reason. France has been cutting nuclear output because the river water used to cool the reactors is too warm.
Everybody wants to import at once. Nobody wants to export. This is the part of the design that assumed the weather in Britain and France would be different.
The grid was built for a country where the emergency arrives in January, wearing a coat. It keeps arriving in July, in shorts, and nobody has updated the plan.