Negative prices (Christmas and Storm Bella)
Thu 24 Dec · Sat 26 Dec · Sun 27 Dec
Research notes
Figures are for London unless they say otherwise.
What happened
- Thu 24 Dec: London reached 0p at 05:00; average 11.1p, peak 29.4p at 17:00; all 14 regions at 0p or below; lowest 0.0p in Eastern England.
- Sat 26 Dec: London was below zero for 1 hour from 23:00, min −1.1p at 23:00; average 9.7p, peak 27.2p at 16:30; all 14 regions at 0p or below; lowest −1.3p in Northern Scotland.
- Sun 27 Dec: London was below zero for 7 hours (longest spell 6.5 hours from 01:00), min −4.2p at 02:30; average 8.0p, peak 29.6p at 17:00; all 14 regions at 0p or below; lowest −5.0p in Northern Scotland.
Likely causes
- Storm Bella affected the UK on 26 and 27 Dec 2020, according to the Met Office's list of named storms for 2020/21. Source: Met Office, UK storm season 2020/21. (confirmed by source; its link to the prices is inference)
- Electric Insights: Christmas Day 2020 was "the first ever coal-free December 25th", and "Boxing Day then saw a slew of clean-energy records". Source: Electric Insights, Q4 2020 headlines. (confirmed by source)
- Thu 24 Dec, 05:00 (London's lowest half-hour): wind 14.6GW (56% of supply), solar 0GW, gas 3.1GW (12%), imports 0.4GW, total supply 26.1GW. Over the day wind averaged 12.9GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sat 26 Dec, 23:00 (London's lowest half-hour): wind 15GW (55% of supply), solar 0GW, gas 2.8GW (10%), imports 1.2GW, total supply 27.2GW. Over the day wind averaged 15GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sun 27 Dec, 02:30 (London's lowest half-hour): wind 13.4GW (52% of supply), solar 0GW, gas 3.6GW (14%), imports 0.4GW, total supply 25.6GW. Over the day wind averaged 10.3GW; the 2020 average was 7.8GW (25%). 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 24 Dec and Sat 26 Dec (14.6GW and 15GW, against 7.8GW for the year). (inference from NESO data)
- The low came overnight on Thu 24 Dec, Sat 26 Dec and Sun 27 Dec, when demand is at its lowest. (inference)
- Sat 26 Dec and Sun 27 Dec were at the weekend, when demand is lower. (inference)
- Elexon market index: Thu 24 Dec averaged £46.27/MWh with a low of £0.73 at 03:30; Sat 26 Dec averaged £22.04/MWh with a low of −£30.26 at 07:00; Sun 27 Dec averaged £42.50/MWh with a low of −£1.98 at 00:30. Source: Elexon market index, Thu 24 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
High. Christmas holiday demand and a named storm on Boxing Day, with wind over half of supply at each low.
Gaps
- Elexon's system warnings feed has no entries before mid-2023, so warnings for these days couldn't be checked there.