January 17, 2025 - 1:00pm

The National Energy System Operator (Neso), the company controlled by Energy Secretary Ed Miliband which runs the national grid, is still insisting that Britain did not come dangerously close to a blackout last week. Even if a major power source had “tripped” offline during the evening of 8 January, when the windless cold weather meant demand was high and supply low because wind farms were barely functioning, Neso claims it could have kept the lights on. Of course, it has not said exactly how.

Still, a forthcoming report by the energy consultant Kathryn Porter, whose blog detailed how tight margins became last week, suggests that Miliband’s plan to make Britain a “clean energy superpower” — using fossil fuels for no more than 5% of its electricity by 2030 — will make the risks much worse.

Porter’s document, to be published next week by the campaign group Net Zero Watch, points out that on a typical winter day, by far the biggest source of electricity is natural gas, which in the colder months currently supplies around 30 gigawatts (GW) — almost two-thirds of the total peak demand. In winter, solar panels are almost useless, while the output from wind fluctuates enormously. On one day last December, it was more than 22GW, but in cold weather it often falls below 1GW. On 8 January, it was 2.5GW.

Miliband insists that there will one day be means to store vast quantities of energy generated by renewables, which can then be used during those periods when the weather means they don’t work. But for now, writes Porter, such technologies “have yet to be deployed anywhere at commercial scale, and some are utterly unproven”. For example, Miliband claims he plans to build more batteries and connect them to the grid. However, existing types of battery “can only run for a matter of hours”, while “periods of low wind can last for days and even weeks.”

Aside from gas, the UK’s only constant electricity source is nuclear. Yet at least two of Britain’s existing reactors are set to close by 2030. Hinkley Point C, the only new one being built, is “very unlikely to be open” by 2030 according to Porter. Interconnectors — the undersea cables linking Britain with Europe that proved essential to avoiding disaster last week — are “also at risk”. In recent years, some have been damaged by accidents, and several countries also facing energy shortages may well decide to restrict electricity exports with the goal of protecting their own consumers — as Norway already has.

Yet another problem Porter identifies is the need to expand the grid massively to connect the new wind and solar facilities promised by Miliband. “Renewables require many more wires and associated grid infrastructure,” she writes. “A gas power station requires a single connection, but a wind farm requires that every single individual turbine is connected.”

Under the Government’s plans, twice as much infrastructure will have to be built in the next five years as has been in the last 10. Already, though, there is evidence that construction is not keeping pace. Last year, the power firm Drax finished building three new gas power stations – more than enough to have covered any shortfall last week. They already have contracts with Neso to supply power when needed, but aren’t running because they are not yet connected to the grid.

Nevertheless, gas will have to fill the gap when the wind refuses to blow over Miliband’s clean energy superpower. In fact, it will be essential to retain all 35GW of existing gas-fired capacity – even though, according to the Energy Secretary, it will be used just 5% of the time.

This will create even more difficulties. Many of the UK’s existing gas plants are close to the end of their normal operational life, and extensions are often impossible. In prolonged periods of disuse, they will have to be protected by “nitrogen blankets”, their tubes filled with nitrogen gas that will take many hours to flush out, as well as by monitoring systems and frequent testing to make sure they work when required.

On Wednesday, Ed Miliband told the Commons energy select committee that by ending dependence on volatile fossil fuel markets, his Clean Power 2030 plan will enhance energy security. Porter disagrees. “The country is not sleepwalking into a security of supply disaster,” she concludes. “Under CP2030, it is running headlong into it.”

Watch UnHerd‘s conversation with Kathryn Porter HERE.


David Rose is UnHerd‘s Investigations Editor.

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