Energy was last better‑than‑free: yesterday Next

On the Agile Octopus tariff, customers get paid to use electricity when there’s too much in the grid.

That’s cheaper than Octopus Energy paying to store it.

The price changes every half-hour.

Period

Region

Negative prices (the night the clocks went back)

Sat 28 Oct · Sun 29 Oct

Figures are for London unless they say otherwise.

Sat 28 Oct: London was below zero for half an hour from 22:30, min −1.2p at 22:30; average 17.8p, peak 40.5p at 17:30; all 14 regions at 0p or below; lowest −1.4p in Northern Scotland.
Sun 29 Oct: London was below zero for half an hour from 07:00, min −0.0p at 07:00; average 13.8p, peak 46.2p at 17:00; all 14 regions at 0p or below; lowest −0.0p in Eastern England.

The clocks went back at 2am on Sun 29 Oct 2023 (the last Sunday in October). Source: GOV.UK, when do the clocks change. (confirmed by source; any effect on prices is not established)
Sat 28 Oct, 22:30 (London's lowest half-hour): wind 14.9GW (51% of supply), solar 0GW, gas 3.1GW (11%), imports 4.9GW, total supply 29.1GW. Over the day wind averaged 10.6GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
Sun 29 Oct, 07:00 (London's lowest half-hour): wind 13.1GW (49% of supply), solar 0.1GW, gas 3.1GW (12%), imports 4.3GW, total supply 26.8GW. Over the day wind averaged 13.9GW; the 2023 average was 9GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
The low came overnight on Sat 28 Oct, when demand is at its lowest. (inference)
Sat 28 Oct and Sun 29 Oct were at the weekend, when demand is lower. (inference)
Elexon market index: Sat 28 Oct averaged £102.34/MWh with a low of £29.33 at 00:30; Sun 29 Oct averaged £59.56/MWh with a low of −£10.49 at 23:30. Source: Elexon market index, Sat 28 Oct. (confirmed by source; a short-term index, not the day-ahead auction Agile follows)

Storm Ciarán followed on 1 and 2 Nov 2023. Source: Met Office, UK storm season 2023/24.

Low. Neither the grid figures nor any report found clearly explain this date.

No news report or official write-up found that ties this date to a cause; the causes above are from the data.

Saturday 28 Oct 2023 · half-hourly prices

South Eastern England

−1.3p

Cheapest half-hour 10.30pm – 11pm

43.3p

Dearest half-hour 5.30pm – 6pm

0.5 hours

Negative prices 10.30pm – 11pm

6.0p avg

Cheapest 3 hours 9pm – 12am

19.4p

Average price on 28 Oct 2023

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