Negative prices (midday)
Research notes
Figures are for London unless they say otherwise.
What happened
- Fri 28 Jun: London was below zero for 1 hour from 14:30, min −2.7p at 15:00; average 7.9p, peak 28.4p at 18:30; all 14 regions at 0p or below; lowest −3.2p in Northern Scotland.
Likely causes
- Fri 28 Jun, 15:00 (London's lowest half-hour): wind 13.4GW (41% of supply), solar 6.4GW, gas 2.9GW (9%), imports 3.3GW, total supply 32.5GW. Over the day wind averaged 13.2GW; the 2024 average was 9.4GW (29%). Source: NESO historic generation mix. (figures confirmed by source; link to prices is inference)
- The low came around midday on Fri 28 Jun, with solar at 6.4GW. (inference from NESO data)
- Elexon market index: Fri 28 Jun averaged £38.99/MWh with a low of −£5.41 at 01:30. Source: Elexon market index, Fri 28 Jun. (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
Medium. The grid figures fit the prices, but no report found names a cause for 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.