The UK grid operator warned that electricity supplies may be tight from Tuesday afternoon, with wind generation set to plunge further overnight.
Britain’s National Energy System Operator flagged a potential shortfall of 1.9 gigawatts between 3 p.m. and 11 p.m. London time, a wider margin than in an earlier message late Monday. Power prices for the evening hours jumped.
The warnings are designed to prompt generators to make additional capacity available and help to rebuild the grid’s supply cushion. NESO often withdraws the notices once extra power has been secured.
With colder weather lifting demand, wind generation becomes increasingly important for keeping the system balanced. Sharp swings in forecasts can quickly leave Britain more reliant on gas-fired power plants to fill the gap.
The outlook for wind generation later Tuesday deteriorated overnight. Output is now forecast at just 2.2 gigawatts at 6 p.m., according to market operator Elexon, about 40% below the forecast a day earlier and just a quarter of this year’s average.
Intraday power prices for delivery between 7 p.m. and 8 p.m. are trading above £400 a megawatt-hour, more than 50% above the level they settled at in an auction on Monday, reflecting the tightening supply outlook closer to delivery.
NESO said it will review the situation again at noon London time.