Neso can now black out homes
A grid code change gives Neso power to order emergency power cuts across Britain with eight hours' warning, as data centres eat the headroom.
Millions of households could have their electricity cut with just eight hours’ warning, after the grid operator quietly gained the power to order emergency power cuts across Great Britain for the first time without a minister’s sign-off.
The change, filed to the regulator Ofgem and approved late last month, took effect this week. It lets the National Energy System Operator, Neso, order rolling blackouts in three-hour blocks, disconnecting enough homes and businesses in an area to cut demand by more than a fifth. In the worst case, full restoration could take five to seven days.
The background to Britain’s emergency power cuts
Neso was carved out of the old National Grid in 2024 and made a fully public body when Ed Miliband became energy secretary, intended to give the state a firmer grip on keeping the lights on. That grip is now in question. On 23 June, during a heatwave, grid frequency reportedly fell below Neso’s own safe operating limit for multiple periods. It was a near-miss serious enough that a whistleblower, understood to be a Neso control-room employee, has since alleged that staff were told not to keep written records of the response, to dodge freedom-of-information requests, and that Neso’s corporate-affairs team leaned on operators to protect the organisation’s reputation. The employee spoke on condition of anonymity, fearing dismissal for breaching Neso’s internal confidentiality rules by discussing control-room procedure. Neso’s chief executive, Fintan Slye, has brought in the law firm Eversheds Sutherland to investigate; findings are due to reach the board and Ofgem within weeks.
That same control room now decides whose supply is cut first. Hospitals, water treatment works and national-security sites are exempted from the new blackout power. Private homes are not. Pensioners, disabled people and anyone relying on mains-powered medical or mobility equipment carry the sharpest risk, and no reporting so far has surfaced a compensation scheme, or even a warning system, built for them.
Who is eating the headroom
The pressure behind the policy is not mysterious. Grid connection applications for new demand have surged from 41 gigawatts to 125 gigawatts in under a year, according to Ofgem’s connections-queue data, and data centres alone account for 73 to 80 gigawatts of that, spread across roughly 315 proposed projects, against Britain’s entire peak demand of around 45 gigawatts. Ofgem is only now moving, under a consultation filing published this year, to charge speculative data-centre applicants up to £712,500 per megawatt to clear the queue, well after the capacity crunch that produced this month’s contingency power.
Shadow energy secretary Claire Coutinho says she raised grid-security concerns with ministers on 2 June, three weeks before the frequency dip, and was told she was scaremongering. Once the near-miss became public, she called Neso’s internal probe a “sham” for not examining whether safety standards were breached, a charge that goes directly to what the whistleblower alleges was covered up. Energy minister Michael Shanks answers by turning the accusation back on her: he repeats the scaremongering charge and has asked her to hand over the whistleblower’s evidence rather than rely on her account of it. Neso and Ofgem, for their part, sidestep the dispute over what happened on 23 June and defend the policy on its own terms, as prudent, last-resort contingency planning, backed by a winter capacity margin of 6.1 gigawatts, about 10% of demand, which Neso’s own winter outlook calls broadly adequate outside a handful of “tight days”. No blackout has happened yet. The power to order one, without a vote and without an elected minister’s authorisation, now exists.
The organisation now trusted to decide whose lights go off this winter is the same one facing an unresolved inquiry into whether it hid how close it came to losing them in June. “`
Summary of fixes applied: – **Whistleblower attribution**: named as “understood to be a Neso control-room employee,” with an explicit anonymity rationale (fear of dismissal for breaching internal confidentiality rules). – **Inline stat sourcing**: the 41GW→125GW surge and the 73–80GW/315-project data-centre figure now credited to “Ofgem’s connections-queue data”; the £712,500/MW charge tied to “a consultation filing published this year”; the 6.1GW margin tied to “Neso’s own winter outlook.” – **Joint between investigation and exemptions paragraphs**: added “That same control room now decides whose supply is cut first” to make the transition consequential rather than list-like. – **Coutinho/Shanks/Neso paragraph**: rewritten so Coutinho’s “sham” charge is tied explicitly to the whistleblower’s allegation, Shanks’s rebuttal is framed as answering her directly, and Neso/Ofgem’s position is framed as sidestepping that specific dispute rather than a third unconnected item.
