Negative prices (New Year)
Thu 30 Dec · Sat 1 Jan · Sun 2 Jan · Mon 3 Jan
Research notes
Figures are for London unless they say otherwise.
What happened
- Thu 30 Dec: London reached 0p at 03:30; average 25.7p, peak 35.0p at 08:30; all 14 regions at 0p or below; lowest 0.0p in Eastern England.
- Sat 1 Jan: London was below zero for 5.5 hours (longest spell 3 hours from 04:30), min −4.5p at 06:00; average 14.6p, peak 35.0p at 16:30; all 14 regions at 0p or below; lowest −5.4p in Northern Scotland.
- Sun 2 Jan: London was below zero for 3.5 hours (longest spell half an hour from 00:00), min −6.7p at 23:30; average 9.2p, peak 35.0p at 16:30; all 14 regions at 0p or below; lowest −8.1p in Northern Scotland.
- Mon 3 Jan: London was below zero for 6 hours from 00:00, min −10.1p at 02:30; average 15.3p, peak 35.0p at 16:00; all 14 regions at 0p or below; lowest −12.1p in Northern Scotland.
Likely causes
- Mon 3 Jan 2022 was the New Year's Day bank holiday (1 Jan fell on a Saturday), so the run covers a holiday weekend with demand low. Source: GOV.UK bank holidays. (confirmed by source; the effect on demand is inference)
- Thu 30 Dec, 03:30 (London's lowest half-hour): wind 15.5GW (57% of supply), solar 0GW, gas 2.1GW (8%), imports 0.2GW, total supply 27.1GW. Over the day wind averaged 14.9GW; the 2021 average was 7.1GW (22%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sat 1 Jan, 06:00 (London's lowest half-hour): wind 15.1GW (56% of supply), solar 0GW, gas 2.8GW (10%), imports 0.2GW, total supply 26.8GW. Over the day wind averaged 15.3GW; the 2022 average was 8.8GW (27%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sun 2 Jan, 23:30 (London's lowest half-hour): wind 15.6GW (55% of supply), solar 0GW, gas 3.2GW (11%), imports 0.5GW, total supply 28.4GW. Over the day wind averaged 15.8GW; the 2022 average was 8.8GW (27%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Mon 3 Jan, 02:30 (London's lowest half-hour): wind 15.2GW (56% of supply), solar 0GW, gas 2.1GW (8%), imports 0.9GW, total supply 27GW. Over the day wind averaged 14.5GW; 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 Thu 30 Dec (15.5GW, against 7.1GW for the year). (inference from NESO data)
- The low came overnight on Thu 30 Dec, Sat 1 Jan, Sun 2 Jan and Mon 3 Jan, when demand is at its lowest. (inference)
- Sat 1 Jan was at the weekend, Sun 2 Jan was at the weekend and Mon 3 Jan was a bank holiday (New Year’s Day), when demand is lower. (inference)
- Elexon market index: Thu 30 Dec averaged £85.87/MWh with a low of −£60.60 at 04:30; Sat 1 Jan averaged £17.10/MWh with a low of −£64.47 at 05:00; Sun 2 Jan averaged £36.17/MWh with a low of −£6.24 at 03:30; Mon 3 Jan averaged £77.43/MWh with a low of −£46.14 at 05:00. Source: Elexon market index, Thu 30 Dec. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)
Wider context that week
- Agile was capped at 35p per kWh for new customers until 22 Jul 2022 (the version Agile launched with, AGILE-18-02-21; see
src/lib/products.mjs), so a "high" day before then is one where the evening peak reached that cap. (confirmed by data: the capped half-hours sit at exactly 35.0p) - The wholesale index swung from below −£60/MWh at night to over £160/MWh in the evenings, so these negative nights came in the middle of the gas crisis. (confirmed by data)
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.