Price spike (low wind)
Research notes
Figures are for London unless they say otherwise.
What happened
- Mon 11 Sep: London peaked at 57.5p at 18:30, average 23.3p, lowest 12.6p at 03:30; highest anywhere 66.5p in Northern Scotland.
Likely causes
- Mon 11 Sep, 18:30 (London's peak): wind 3.5GW (10% of supply), solar 0.3GW, gas 18.8GW (53%), imports 2.3GW, total supply 35.2GW. Over the day wind averaged 5GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Wind was less than half its yearly average at the peak on Mon 11 Sep (3.5GW, against 9GW for the year), so gas made up the gap. (inference from NESO data)
- The peak came in the early evening on Mon 11 Sep, when demand is highest and there is no solar. (inference)
- Elexon market index: Mon 11 Sep averaged £92.38/MWh with a high of £155.71 at 18:00. Source: Elexon market index, Mon 11 Sep. (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.