Negative prices (midday, weekend)
Research notes
Figures are for London unless they say otherwise.
What happened
- Sat 11 Jun: London was below zero for 3 hours from 13:00, min −4.4p at 14:30; average 13.2p, peak 30.1p at 18:30; all 14 regions at 0p or below; lowest −5.3p in Northern Scotland.
Likely causes
- Sat 11 Jun, 14:30 (London's lowest half-hour): wind 14.1GW (42% of supply), solar 7.1GW, gas 3.4GW (10%), imports 1.3GW, total supply 33.2GW. Over the day wind averaged 13.1GW; the 2022 average was 8.8GW (27%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The low came around midday on Sat 11 Jun, with solar at 7.1GW. (inference from NESO data)
- Sat 11 Jun was at the weekend, when demand is lower. (inference)
- Elexon market index: Sat 11 Jun averaged £73.73/MWh with a low of −£20.26 at 03:30. Source: Elexon market index, Sat 11 Jun. (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
Medium. The grid figures fit the prices, but no report found names a cause for this date.
Gaps
- No news report or official write-up found that ties this date to a cause; the causes above are from the data.
- Elexon's system warnings feed has no entries before mid-2023, so warnings for these days couldn't be checked there.