by A. Montford, Sept 12,2025 in NetZeroWatch
When the wind isn’t blowing and the sun isn’t shining, we rely on so-called ‘firm capacity’ to step in and keep the lights on. In the UK, that means gas-fired and nuclear power stations and pretty much nothing else – the giant wood-burner at Drax is the only significant exception.
Unfortunately, both the gas-fired and nuclear fleets are now very old, and much of the capacity is nearing the end of its life. Regulators have granted extensions to some of the nuclear units, but after 2028 permanent closures are likely. Meanwhile, as much as a third of our gas-fired capacity is expected to retire over the next five years.
Unless these units can be replaced, or their lives extended, we face a capacity crunch by 2030 at the latest. At best that means sky-high prices, and at worst, brownouts – electricity rationing in other words. That is a horrific prospect. As the Spanish found out to their cost during the recent Iberian blackout, when the power supply goes down, people die.
However, replacement is currently looking unlikely. With so much wind and solar on the grid, nobody wants to put money into new power stations, either gas-fired or nuclear. The financial numbers simply don’t add up any longer, either for new units or for overhauls of existing ones.
In theory, we could subsidise our way out of this. Although little or no new capacity has emerged from the government’s capacity market auctions, if caps on prices were removed, in theory someone might take the risk.
However, in practice this won’t happen. That’s because a surge in power demand from new datacentres means that the lead time for a new gas turbine is now eight years. Lead times for nuclear are mostly even longer – the Koreans have delivered in as little as eight years, but everyone else takes much longer. And this is the United Kingdom, where building anything takes an eternity.
Either way, new gas turbines or nuclear will arrive too late to help the UK avoid a capacity crunch.
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