A new demand control rotation protocol enabling rolling three-hour power cuts has been introduced by the UK’s National Energy System Operator (NESO).
The protocol can be actioned without prior government approval, to prevent system collapse in extreme supply shortfalls.
Millions of people in businesses and homes could be affected, switching off lights and crucial systems.
Protected sites such as hospitals, homes, water treatment works and national security locations are exempt.
NESO described the tool as a last-resort measure after all other options are exhausted.
Ofgem has previously noted that existing emergency powers are not suited to short-notice use.
Shadow Energy Secretary Claire Coutinho criticised NESO for taking “more and more extreme measures.”
Experts believe that it would take around a week to fully restore a worst-case system collapse. The protocol allows NESO to avoid a full system collapse and keep the lights on in most areas.
The protocol has a built-in notice period of eight hours.
The rotation plan means that the remaining 90% of supply is divided into 18 blocks (around 5% each) to cut load by over 20% per block, with 10% reserved for protected sites.
NESO has stressed that the protocol would only be used in “the most extreme and unlikely circumstances” and help mitigate against power cuts.
In other power news, constraint payments to curtail wind generation have reached £1 billion in 2026, some two months earlier than in 2025.
This reflects transmission bottlenecks between Scotland and demand centres in southern England.
Reported figures include £300 million more than the same point in 2025, £21 million on July 2 as the worst single day, a government estimate of up to £10 billion by 2030 and £3.2 billion predicted for next year alone.
An Octopus Energy spokesperson called the situation “bonkers,” arguing for cheaper local use of wind.
The potential savings cited were £114 per household annually if markets were regionally split.
