Price spike (at the cap)
Mon 7 Dec · Tue 8 Dec · Wed 9 Dec
Research notes
Figures are for London unless they say otherwise.
What happened
- Mon 7 Dec: London peaked at 35.0p at 16:30 (Agile's 35p cap), average 15.5p, lowest 7.3p at 04:30; highest anywhere 35.0p in Eastern England.
- Tue 8 Dec: London peaked at 35.0p at 16:30 (Agile's 35p cap), average 15.2p, lowest 6.7p at 23:30; highest anywhere 35.0p in Eastern England.
- Wed 9 Dec: London peaked at 35.0p at 16:30 (Agile's 35p cap), average 16.6p, lowest 6.3p at 22:30; highest anywhere 35.0p in Eastern England.
Likely causes
- Mon 7 Dec, 16:30 (London's peak): wind 5.7GW (12% of supply), solar 0GW, gas 23.8GW (50%), imports 2.9GW, total supply 47.6GW. Over the day wind averaged 3.9GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Tue 8 Dec, 16:30 (London's peak): wind 6.5GW (14% of supply), solar 0GW, gas 23.4GW (49%), imports 3.8GW, total supply 47.4GW. Over the day wind averaged 6.8GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Wed 9 Dec, 16:30 (London's peak): wind 5.5GW (12% of supply), solar 0GW, gas 23.3GW (50%), imports 3.8GW, total supply 46.9GW. Over the day wind averaged 6.1GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The peak came in the early evening on Mon 7 Dec, Tue 8 Dec and Wed 9 Dec, when demand is highest and there is no solar. (inference)
- Elexon market index: Mon 7 Dec averaged £115.50/MWh with a high of £272.79 at 16:30; Tue 8 Dec averaged £57.86/MWh with a high of £101.43 at 16:30; Wed 9 Dec averaged £65.57/MWh with a high of £127.82 at 16:30. Source: Elexon market index, Mon 7 Dec. (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.