Negative prices at lunchtime, record solar
Research notes
Figures are for London unless they say otherwise.
What happened
London fell to −3.9p at 13:30 and was below zero for 4 hours (longest spell 3.5 hours from 12:30). The average was 15.6p, with a normal evening peak of 35.3p at 18:30.
Likely causes
- Britain set a new solar generation record of 14,414 MW between 12:30 and 13:00 on 7 Apr, the same half-hour the negative spell began. It beat 14,147 MW set the day before (6 Apr, Easter Monday), which had itself beaten the 8 Jul 2025 record of 14,023 MW. (confirmed by source) Transport and Energy, 9 Apr 2026, NESO, 24 Apr 2026
- Wind was still healthy as Storm Dave's tail cleared: on the morning of 8 Apr wind was over 41% of the mix and low-carbon sources were meeting close to 60% of demand. (confirmed by source for 8 Apr; carried back to 7 Apr as an inference) Prestige, 8 Apr 2026
- Temperatures were 4 to 5°C above normal across north-west Europe, keeping demand low on the first working day after Easter. (confirmed by source) Prestige, 7 Apr 2026
Wider context that week
- Same as the Easter section: markets opened higher on Hormuz tension on 7 Apr, then fell sharply on the 8 Apr ceasefire. Day-ahead baseload for 8 Apr had settled at £110.60/MWh, showing how expensive the non-solar hours still were. Prestige, 8 Apr 2026
Confidence
High for solar as the cause (record set in the very half-hour prices went negative). Medium for the wind contribution.
Gaps
- No wind figure for 7 Apr itself.