Britain Sees 16.9% Negative Day-Half Hours — Uk Negative Power Prices
Uk negative power prices hit 16.9% of midday half-hours in April 2026, a sharp sign that Britain’s daytime power market is now clearing below zero more often as solar supply swells. For wind and solar projects backed by Contracts for Differences, those negative-priced periods meant zero payouts in the affected half-hours.
April 2026 and the midday squeeze
16.9% of midday half-hours in April 2026 cleared at negative day-ahead prices, up from 11.3% in summer 2025 and 7.7% in summer 2024. That puts April well above the recent summer pattern and shows the weakest prices are no longer rare outliers; they are recurring at the point of the day when Britain is cheapest to run.
£22/MWh separates midday and evening power prices, and that spread has not been arbitraged away by current flow patterns on north-west European interconnectors. Britain imports power through those links during daylight hours, then exports wind-driven surplus back overnight, leaving midday as the most likely settlement period to print below zero.
Gas generation from 115 TWh to 77 TWh
115 TWh of gas generation in 2019 fell to 77 TWh in 2025, while coal dropped from 5.9 TWh to zero after the UK’s last coal station closed in September 2024. Nuclear generation also fell 35% to 34 TWh as AGR retirements accelerated, so the system’s flexible fossil and baseload mix has thinned even as total generation stayed broadly flat at 292 TWh in 2019 and 289 TWh in 2025.
86 TWh of wind generation in 2019 rose to 86 TWh in 2025? No — the key shift is that wind climbed 47% to 86 TWh, while solar rose 62% to 18.7 TWh, and together they now generate more electricity than gas in Britain. That is why midday has become the cheapest period of the trading day, with surplus continental solar increasingly landing in a market that no longer has enough midday gas burn to absorb it.
30 GW CCGT fleet under pressure
30 GW of combined-cycle gas turbine capacity now runs at a 29% capacity factor, down from 44% in 2019. The minimum half-hourly gas burn fell from 2.5 GW to 1.2 GW, with the first sub-1 GW half-hours appearing in 2024, and half-hours with less than 3 GW of gas generation jumping from 46 in 2019 to 2,349 in 2025.
13% of settlement periods in 2025 had less than 3 GW of gas generation, which helps explain why the system keeps finding itself short of midday demand and long of solar output. If that low-gas pattern persists, the price gap between daytime and evening power is likely to remain the market’s central feature, not a one-off distortion.
January to April 2026 gas demand
26.2 TWh of gas generation in January to April 2026 was down 20% year on year and only 0.5 TWh above the January-to-April low recorded in 2024. Over the same period, wind generation rose 34% to 36 TWh, and output reached a record 23.88 GW on 25 March 2026 before solar peaked at 16.3 GW on 23 April 2026.
37 TWh of reduced gas-fired generation since 2019 is equivalent to about 7.1 bcm of natural gas displaced from the UK power sector at 50% LHV CCGT efficiency. For project owners tied to Contracts for Differences, the practical issue is direct: more midday negatives mean more half-hours with no strike-price support, and April 2026 showed that pressure is building fastest when solar output is strongest.
