Zero price at midnight (the night before Storm Darragh)
Research notes
Figures are for London unless they say otherwise.
What happened
- London touched exactly 0.0p at 00:00 and never went below. Daily average 18.3p, evening peak 39.1p. All 14 regions reached 0p.
Likely causes
- A burst of strong wind late on Thu 5 Dec. NESO data: wind was 21.3GW (64% of supply) at 00:00 on Fri, the day's high, with gas down to 3.0GW. It then fell away to 7.1GW by 14:00. Source: NESO historic generation mix. Figures (confirmed by source); link to price (inference).
- This was not Storm Darragh itself. Darragh's yellow wind warning began at 15:00 on Fri 6 Dec, and the red and amber warnings covered the early hours of Sat 7 Dec onwards. Source: Met Office, Storm Darragh report (PDF), Met Office news: red warning. (confirmed by source) The zero price came from the system that passed through ahead of it. (inference)
Wider context that week
- Storm Darragh (6 to 7 Dec) brought gusts up to 96mph and cut power to more than 2.3 million customers across Wales and central and northern England. Royal Meteorological Society, State of the Climate for the UK Energy Sector 2024-25. Worth knowing that Sat 7 Dec, the storm day itself, does not appear in the data file as a zero or negative day.
- Tue 3 Dec saw the winter's second capacity market notice (issued 13:04 for 17:30, cancelled 14:35). Not an event day in the price data, but it shows how tight the early-December evenings were. Elexon system warnings feed
- Bloomberg reported on 2 Dec that the UK was on course to pay £1bn in 2024 to waste a record amount of wind power. Bloomberg, 2 Dec (headline only; article paywalled)
Confidence
Medium. The wind data explains a zero price at midnight well. Nothing in the press about it, and the price only touched zero for one half-hour.
Gaps
Did not find a Met Office description of the weather system on the evening of Thu 5 Dec. Did not establish why Sat 7 Dec (Darragh itself) stayed above zero; one plausible reason is turbines shutting down in extreme gusts, but I found no source for that on this date, so it is left out.