Negative prices
Research notes
Figures are for London unless they say otherwise.
What happened. London down to −2.4p at 11:30, below zero for 5.5 hours from 10:30, average 12.8p.
Likely causes
- The highest solar output of the whole period: PV_Live peaks at about 15.8 GW at 13:00 to 13:30 BST. Not a record; PV_Live shows about 16.4 GW on 23 Apr 2026 (confirmed by data) PV_Live 12 Jul
- Wind was moderate (6.8 GW average, against about 2 GW on 8 to 10 Jul), and gas plant fell to 2.1 GW at the low point (confirmed by data) Elexon FUELHH 12 Jul
- Sunday demand, the lowest of the week (inference).
Wider context that week. This was the weekend of US strikes on Iran and Iranian attacks on Bahrain, Kuwait and Jordan, and Qatar's order for ships to stop sailing; gas jumped about 4% on Mon 13 Jul Catalyst 13 Jul. NESO had issued an Electricity Margin Notice for the evening of 9 Jul in the heat Energy Live News, 9 Jul 2026. The Jul heatwave peaked at 35.5°C at Wisley on 9 Jul.
Confidence. Medium to high. The data explains it well, but nothing published mentions the day.
Gaps. No article or market report about 12 Jul's prices.