Negative prices over Easter (Storm Dave)
Sat 4 Apr · Sun 5 Apr
Research notes
Figures are for London unless they say otherwise.
What happened
- Sat 4 Apr: London fell to −5.0p at 23:30, below zero for 4.5 hours (longest spell 3.5 hours from 12:30), average 7.8p.
- Sun 5 Apr (Easter Sunday): London fell to −11.3p at 12:30 and was below zero for 16 hours straight from midnight. The average was just 1.3p. Lowest anywhere was −12.8p in Northern Scotland. This was the deepest negative price of the half-year.
Likely causes
- Storm Dave, named by the Met Office on 2 Apr, crossed the UK on 4 and 5 Apr. An amber wind warning ran from 19:00 Sat to 03:00 Sun for northern England, southern Scotland and north-west Wales. Capel Curig recorded a 93 mph gust, and the Met Office called it the "most severe April windstorm since naming began in 2015". (confirmed by source) Met Office: Storm Dave in context, Met Office amber warning, 4 Apr, Met Office season review
- The market link is made directly: "Storm Dave delivered strong wind generation over the Easter weekend during reduced holiday demand, pulling prompt prices sharply lower", and "UK power prices had already spent much of Easter Sunday in negative territory owing to the combination of low holiday demand and high renewable output." (confirmed by source) Prestige, 7 Apr 2026, Prestige, 8 Apr 2026
- The GB day-ahead daily average on 5 Apr was €6.84/MWh, the lowest since Oct 2025. GB demand was down 6.7% on the week before, put down to warmer weather and Easter. (confirmed by source) AleaSoft, 7 Apr 2026
- Easter Sunday afternoon was forecast dry with "good sunny periods" in the south, so solar added to the surplus around the 12:30 low. (forecast confirmed by source; effect is an inference) Met Office, 4 Apr
- These were the first negative days after Agile rates dropped by 3.5p/kWh on 1 Apr, which makes every negative price from here on a little deeper than it would have been in March. (confirmed by source for the rate change; the effect on depth is an inference) Octopus: Agile pricing explained
Wider context that week
- Good Friday was 3 Apr and Easter Monday 6 Apr, so this was a four-day weekend of low demand.
- The week had started with GB day-ahead prices above €100/MWh on 1 Apr. TTF gas was about €47.5/MWh on 1 Apr, its lowest since 11 Mar. AleaSoft, 7 Apr 2026
- Energy markets reopened sharply higher after Easter on US-Iran tension at the Strait of Hormuz. A two-week US-Iran ceasefire was then announced on 8 Apr and gas, power and oil all fell heavily. Prestige, 7 Apr, Prestige, 8 Apr, Wikipedia: 2026 Iran war fuel crisis
Confidence
High. A named storm, a bank holiday weekend, and two market sources that make the connection in so many words.
Gaps
- No GB wind output figure (GW) for either day.
- Octopus social posts about "plunge pricing" that weekend were not searched for (search budget ran out).