Negative prices (clock-change day)
Research notes
Figures are for London unless they say otherwise.
What happened
London fell to −5.1p at 04:30 and was below zero for 9 hours in total (longest spell 3.5h from 02:30). All 14 regions negative, lowest −6.1p in Northern Scotland. Daily average only 7.8p.
Likely causes
- AleaSoft confirms the British day-ahead market recorded negative prices on 30 Mar, alongside Belgium and France. It does not give a British cause. (confirmed by source) pv magazine, 4 Apr 2025
- Strong wind overnight and strong sun by day. Transmission-metered wind was 16.0GW just after midnight and averaged 11.0GW; solar peaked at about 12.7GW in the early afternoon. Gas dropped to 1.6GW mid-morning and GB exported up to 4.5GW around 04:00. (confirmed by source: grid data) Elexon FUELHH 30 Mar 2025 · PV_Live 30 Mar 2025
- Two separate negative spells, a windy small-hours one and a sunny midday one, would explain 9 negative hours with a longest single spell of only 3.5. (inference)
- Sunday demand is low, and this was the day the clocks went forward (a 23-hour day, 46 half-hours in the settlement data). The clock change itself is not a cause, just a detail for the post. (inference)
- March 2025 was England's sunniest March on record (185.8 hours), with persistent high pressure. (confirmed by source) Met Office, 1 Apr 2025
Wider context that week
- The Ofgem cap rose 6.4% to £1,849 on Tue 1 Apr, driven mostly by the winter's wholesale spike. A post can contrast that with negative Agile prices two days earlier. Ofgem
- On 1 Apr NESO recorded a then-record 12.2GW of solar (12:30 to 13:00) and a record 97.7% zero-carbon half-hour. ECIU, 1 Apr 2025 · NESO 2025 review
- European gas storage ended March about 33% full against 59% a year earlier, but prices had fallen back from February's peak. Elenger Q1 2025
Confidence
High on the cause (grid data is unambiguous), though only one external source mentions the negative prices and it gives no detail.
Gaps
No UK news report found for this date, and no Met Office note about the wind that night. No wholesale price figure (how negative the hourly price went) was found.