Price spike (at the cap)
Research notes
Figures are for London unless they say otherwise.
What happened
- Thu 27 Aug: London peaked at 35.0p at 17:30 (Agile's 35p cap), average 13.0p, lowest 6.7p at 03:30; highest anywhere 35.0p in Eastern England.
Likely causes
- Thu 27 Aug, 17:30 (London's peak): wind 4GW (11% of supply), solar 0.8GW, gas 18.1GW (51%), imports 3.6GW, total supply 35.3GW. Over the day wind averaged 3GW; 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 Thu 27 Aug, when demand is highest and there is no solar. (inference)
- Elexon market index: Thu 27 Aug averaged £43.73/MWh with a high of £55.69 at 18:00. Source: Elexon market index, Thu 27 Aug. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)
Wider context that week
- Storm Francis (Tue 25 Aug) was within a few days of it. Source: Met Office, UK storm season 2019/20. (confirmed by source; its effect on these prices is inference)
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.