Negative prices (Storm Kathleen)
Sat 6 Apr · Sun 7 Apr
Research notes
Figures are for London unless they say otherwise.
What happened
- Sat 6 Apr: London was below zero for 8.5 hours (longest spell 5.5 hours from 10:30), min −3.8p at 13:30; average 2.8p, peak 19.9p at 18:00; all 14 regions at 0p or below; lowest −4.5p in Northern Scotland.
- Sun 7 Apr: London was below zero for 11 hours (longest spell 6.5 hours from 01:00), min −1.7p at 06:00; average 3.7p, peak 22.3p at 18:30; all 14 regions at 0p or below; lowest −2.0p in Northern Scotland.
Likely causes
- Storm Kathleen affected the UK on 6 and 7 Apr 2024, according to the Met Office's list of named storms for 2023/24. Source: Met Office, UK storm season 2023/24. (confirmed by source; its link to the prices is inference)
- Sat 6 Apr, 13:30 (London's lowest half-hour): wind 18.1GW (50% of supply), solar 7GW, gas 1.7GW (5%), imports 3.7GW, total supply 36.2GW. Over the day wind averaged 18GW; the 2024 average was 9.4GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Sun 7 Apr, 06:00 (London's lowest half-hour): wind 17.9GW (66% of supply), solar 0GW, gas 2.4GW (9%), imports 0.4GW, total supply 27GW. Over the day wind averaged 18.6GW; the 2024 average was 9.4GW (29%). 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 Sat 6 Apr and Sun 7 Apr (18.1GW and 17.9GW, against 9.4GW for the year). (inference from NESO data)
- The low came around midday on Sat 6 Apr, with solar at 7GW. (inference from NESO data)
- The low came overnight on Sun 7 Apr, when demand is at its lowest. (inference)
- Sat 6 Apr and Sun 7 Apr were at the weekend, when demand is lower. (inference)
- Elexon market index: Sat 6 Apr averaged £6.47/MWh with a low of −£27.72 at 07:00; Sun 7 Apr averaged £0.87/MWh with a low of −£61.09 at 11:00. Source: Elexon market index, Sat 6 Apr. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)
Wider context that week
- Electric Insights: fossil fuels fell to a record low of 0.89GW on 5 Apr 2024, the day before, "the first time they have produced less than 1 GW in a century". Source: Electric Insights, Power system records (Q2 2024). (confirmed by source)
Confidence
High.
Gaps
- None beyond what is said above.