Negative prices (overnight)
Research notes
Figures are for London unless they say otherwise.
What happened
- Tue 3 Oct: London was below zero for half an hour from 04:30, min −1.1p at 04:30; average 14.1p, peak 38.1p at 18:30; all 14 regions at 0p or below; lowest −1.3p in Northern Scotland.
Likely causes
- Tue 3 Oct, 04:30 (London's lowest half-hour): wind 11.4GW (48% of supply), solar 0GW, gas 4.7GW (20%), imports 1.3GW, total supply 23.5GW. Over the day wind averaged 15.1GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The low came overnight on Tue 3 Oct, when demand is at its lowest (total supply as low as 23.5GW, against a 2023 average of 31.3GW). (inference)
- Elexon market index: Tue 3 Oct averaged £49.58/MWh with a low of −£7.75 at 03:00. Source: Elexon market index, Tue 3 Oct. (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
Low. Neither the grid figures nor any report found clearly explain 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.