Negative prices are back.
And they are getting less rare.
Britain's wholesale power price has dipped below zero again. A few years ago that was a freak event worth a news story. This year it is on track to happen for hundreds of hours. The word for something that happens hundreds of hours a year is not freak. It is normal.
📊 More than double, in one year
Analysts now expect around 306 hours of below-zero prices across 2026. That is more than double last year, and the sharpest jump since anyone started counting.
The cause is not mysterious. Britain is adding roughly 7.4GW of new wind and solar this year alone. Solar capacity has pushed past 20GW, helped along by several hundred thousand new rooftops.
All of that generation has one thing in common: it produces when the weather says so, not when you say so.
🪫 Nobody built the sponge
We built an enormous amount of generation and a much smaller amount of storage. So when supply overshoots, there is nowhere to put the extra.
Prices go negative because a generator would rather pay a small amount to keep running than shut down and lose its subsidy or its market position. Someone, somewhere, has to absorb the electricity.
Right now the absorbers are a handful of grid batteries, a cable to France, and the off switch. That is a thin list for a country producing this much power.
🏠 The sponge is in your house
Every EV is a battery. Every home battery is a battery. Every hot water tank is a thermal battery that most people have never once thought of as one.
There are millions of them, already installed, already paid for, sitting idle for 23 hours a day.
The grid does not need you to buy anything. It needs you to let it choose the hour.
Three hundred and six hours a year when electricity is worth less than nothing, in a country where people are choosing between heating and eating. We have not got a generation problem. We have got a timing problem.