UK Grid Operator Flags Rare Morning Power Gap as Wind Output Sags

Neso flagged a shortfall of almost 1,400 megawatts in its electricity supply margins between 6am and 11am on Monday, driven by forecasts of weak wind power generation across Europe. The notice went out on Sunday night and asked the market to find roughly 800 megawatts of extra generation — about the size of a medium-sized gas power plant — within eight hours, ahead of a 4am supply review.

That pre-dawn review worked. A second electricity margin notice showed Neso's late margin call cut the shortfall to 500 megawatts. No further contingency power was needed, though the operator said it could still ask plants to run above their usual output between 8am and 11am. Another supply review was set for 7.30am.

A Neso spokesperson called the notice a routine, precautionary step that gives the market a chance to bring extra capacity forward. There is no warning of power cuts, no risk to customer supplies and no action needed from households, the spokesperson said, adding that Great Britain's electricity system remains secure.

The timing is what stands out. These notices have traditionally landed on cold winter evenings when demand peaks, but Neso has issued more alerts recently — including its first summer margin notices, when heatwaves lifted demand while curbing generation.

Nothing in the grid itself was blocking power plants or windfarms, and the UK was forecast to export electricity to Europe. That points to low wind speeds across the continent, which trimmed renewable output at the end of last week, as the likely trigger for the gap.