Negative prices (lockdown Easter)
Sun 12 Apr · Mon 13 Apr
Research notes
Figures are for London unless they say otherwise.
What happened
- Sun 12 Apr: London was below zero for half an hour from 23:30, min −1.0p at 23:30; average 7.3p, peak 19.3p at 17:30; all 14 regions at 0p or below; lowest −1.2p in Northern Scotland.
- Mon 13 Apr: London was below zero for 8 hours (longest spell 5.5 hours from 02:00), min −2.1p at 06:00; average 4.7p, peak 21.0p at 18:00; all 14 regions at 0p or below; lowest −2.5p in Northern Scotland.
Likely causes
- Octopus's lockdown post, updated on 22 Apr 2020, describes negative Agile prices in this period as social distancing cut demand while it was sunny and windy. Source: Octopus Energy blog, 8 Apr 2020. (confirmed by source)
- Sun 12 Apr, 23:30 (London's lowest half-hour): wind 13.2GW (55% of supply), solar 0GW, gas 3.6GW (15%), imports 0.5GW, total supply 24GW. Over the day wind averaged 5.5GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- Mon 13 Apr, 06:00 (London's lowest half-hour): wind 10.6GW (48% of supply), solar 0GW, gas 3.7GW (17%), imports 1.3GW, total supply 22GW. Over the day wind averaged 8.5GW; the 2020 average was 7.8GW (25%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The low came overnight on Sun 12 Apr and Mon 13 Apr, when demand is at its lowest (total supply as low as 22GW, against a 2020 average of 31.4GW). (inference)
- Sun 12 Apr was at the weekend and Mon 13 Apr was a bank holiday (Easter Monday), when demand is lower. (inference)
- Elexon market index: Sun 12 Apr averaged £27.82/MWh with a low of £1.60 at 00:30; Mon 13 Apr averaged £11.59/MWh with a low of −£33.63 at 04:30. Source: Elexon market index, Sun 12 Apr. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)
Wider context that week
- The first national lockdown in England began on 23 Mar 2020 ("stay at home"); people who couldn't work from home were asked to return from 10 May, non-essential shops reopened on 15 Jun, and pubs and restaurants on 4 Jul. Source: GOV.UK, timeline of COVID-19 restrictions in 2020 (PDF). (confirmed by source)
- Elexon found that GB electricity demand was 19% lower in Apr and May 2020 than a year earlier, "driven by the COVID-19 lockdown measures", and that 83% of the year's negative system prices to June fell in April and May. Source: Elexon: negative system prices during COVID-19, last updated 29 Jun 2020. (confirmed by source; these are system prices, not the day-ahead prices Agile follows)
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.
- Elexon's system warnings feed has no entries before mid-2023, so warnings for these days couldn't be checked there.