Price spike (the gas price record, every half-hour at the cap)
Research notes
Figures are for London unless they say otherwise.
What happened
- Thu 7 Oct: London peaked at 35.0p at 00:00 (Agile's 35p cap), average 35.0p, lowest 35.0p at 00:00; highest anywhere 35.0p in Eastern England.
Likely causes
- Every half-hour that day was at Agile's 35p cap, so London's average was 35.0p. (confirmed by data)
- UK wholesale gas prices rose nearly 40% in one session on 6 Oct 2021, the day before, to over 400p per therm, and more than doubled over the previous month; the causes given are demand recovering after Covid, especially in Asia, supply disruptions, expectations of a cold winter and unusually low wind. Source: interactive investor, 6 Oct 2021. (confirmed by source)
- Thu 7 Oct, 00:00 (London's peak): wind 7GW (28% of supply), solar 0GW, gas 7GW (28%), imports 3.9GW, total supply 25GW. Over the day wind averaged 8.7GW; the 2021 average was 7.1GW (22%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Elexon market index: Thu 7 Oct averaged £202.15/MWh with a high of £316.11 at 07:30. Source: Elexon market index, Thu 7 Oct. (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)
Confidence
High. A record gas price the day before, and wholesale power so high that no half-hour fell below the cap.
Gaps
- Elexon's system warnings feed has no entries before mid-2023, so warnings for these days couldn't be checked there.