A heatwave made electricity free.
We mostly slept through it.
Europe baked this weekend. Solar panels from Seville to Suffolk went into overdrive, output overwhelmed demand, and wholesale power prices across the continent fell below zero. Britain caught the edge of it. For a few hours, electricity was not just cheap. It was worth less than nothing.
☀️ Too much of a good thing
A heatwave is a strange event for a power grid. It pushes demand up, because fans and air conditioning and fridges all work harder. It also pushes supply up, hard, because the thing causing the heat is also the thing powering the solar panels.
This weekend supply won. Solar output across Europe was enormous, demand was a lazy weekend, and prices collapsed through zero.
Negative prices mean generators were paying to get rid of their electricity. Not selling it. Paying.
🥶 The cruel joke of a British summer
Here is the bit that should annoy you. The cheapest electricity of the entire year arrives on the days when you least want to run anything.
Nobody is doing a hot wash at 1pm in a heatwave. Nobody is heating the house. Nobody is charging the car, because the car is on a driveway in Cornwall.
So the free power arrives, and the average household is out. Automated households were in. Their batteries filled, their tanks heated, their cars charged, all at prices that dipped below nothing.
🌙 And then the sun went down
At around 8pm the solar disappears in under an hour. Demand is still high, because it is still hot and everyone has come home and switched the fan back on.
Gas plants fire up to cover it, and the price goes vertical. Same day. Same grid. Sometimes a tenfold difference between lunch and dinner.
If your appliances ran at 8pm instead of 1pm, you paid the peak price for the privilege of missing the free one.
Britain finally got a heatwave and the grid responded by making electricity free, which we celebrated by not using any. There is a version of this weekend where your car charged for nothing while you were in a beer garden. The car does not need you there. That is rather the point.