Negative prices (overnight, weekend)
Research notes
Figures are for London unless they say otherwise.
What happened
- Sun 6 Feb: London was below zero for half an hour from 04:30, min −0.1p at 04:30; average 25.7p, peak 35.0p at 08:30; all 14 regions at 0p or below; lowest −0.1p in South Western England.
Likely causes
- Sun 6 Feb, 04:30 (London's lowest half-hour): wind 17.3GW (60% of supply), solar 0GW, gas 2.4GW (8%), imports 1.4GW, total supply 28.9GW. Over the day wind averaged 17.6GW; the 2022 average was 8.8GW (27%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Wind was well above its yearly average at the lowest half-hour on Sun 6 Feb (17.3GW, against 8.8GW for the year). (inference from NESO data)
- The low came overnight on Sun 6 Feb, when demand is at its lowest. (inference)
- Sun 6 Feb was at the weekend, when demand is lower. (inference)
- Elexon market index: Sun 6 Feb averaged £114.09/MWh with a low of −£15.42 at 04:30. Source: Elexon market index, Sun 6 Feb. (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.