Negative prices (a record low day-ahead price)
Sat 1 Jul · Sun 2 Jul
Research notes
Figures are for London unless they say otherwise.
What happened
- Sat 1 Jul: London was below zero for 3.5 hours (longest spell 1.5 hours from 13:30), min −2.1p at 23:30; average 8.8p, peak 27.1p at 18:30; all 14 regions at 0p or below; lowest −2.5p in Northern Scotland.
- Sun 2 Jul: London was below zero for 9 hours (longest spell 8 hours from 08:00), min −18.1p at 14:00; average 2.7p, peak 23.2p at 22:00; all 14 regions at 0p or below; lowest −21.7p in Northern Scotland.
Likely causes
- Modo Energy: on Sun 2 Jul 2023 "a new record low was set in the EPEX hourly day-ahead market at £-70/MWh", and "day-ahead prices remained negative across 17 consecutive hours", as "high levels of wind and solar generation coincided with lower demand" across almost all of Europe. Source: Modo Energy, 3 Jul 2023. (confirmed by source)
- Octopus paid customers to use more electricity between 8am and 4pm on 2 Jul, saying wind and solar "generated over 60% of the UK's energy" that weekend while demand was down. Source: Solar Power Portal, 4 Jul 2023. (confirmed by source)
- System warning published 1 Jul, 23:05: "Notification of National Grid Emergency Instruction to a BM Participant National Grid has issued an Emergency Instruction to SGRWO-6 on 01/07/2023 22:55" Source: Elexon system warnings. (confirmed by source)
- Sat 1 Jul, 23:30 (London's lowest half-hour): wind 13GW (53% of supply), solar 0GW, gas 4.3GW (18%), imports 0.2GW, total supply 24.3GW. Over the day wind averaged 13.2GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sun 2 Jul, 14:00 (London's lowest half-hour): wind 11.1GW (36% of supply), solar 6.4GW, gas 3.2GW (11%), imports 3.4GW, total supply 30.4GW. Over the day wind averaged 11.9GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The low came around midday on Sun 2 Jul, with solar at 6.4GW. (inference from NESO data)
- The low came overnight on Sat 1 Jul, when demand is at its lowest (total supply as low as 24.3GW, against a 2023 average of 31.3GW). (inference)
- Sat 1 Jul and Sun 2 Jul were at the weekend, when demand is lower. (inference)
- Elexon market index: Sat 1 Jul averaged £2.91/MWh with a low of −£40.71 at 15:00; Sun 2 Jul averaged £6.46/MWh with a low of −£69.27 at 14:00. Source: Elexon market index, Sat 1 Jul. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)
Wider context that week
- Nothing notable found for that week.
Confidence
High. A published record day-ahead low on the day, and Octopus describing it.
Gaps
- None beyond what is said above.