Price spike (Agile hit the 100p cap)
Research notes
Figures are for London unless they say otherwise.
What happened
The most expensive day of the period on average: London averaged 49.1p and hit the 100p cap at 15:30. Overnight low was 13.2p.
Likely causes
- Wind was even lower than on 8 Jan. Transmission-metered wind averaged 3.7GW and fell to 1.9GW by 22:00. Gas ran hard all day, averaging 20.5GW and peaking at 24.9GW at 17:00, with imports up to 6.9GW. (confirmed by source: grid data) Elexon FUELHH 10 Jan 2025
- Deep cold. The night of 10 to 11 Jan was the UK's coldest January night in 15 years, −18.9°C at Altnaharra. (confirmed by source) ITV News, 11 Jan 2025
- Reuters that day tied the two together: cold weather and snow pushed up heating demand while low wind speeds cut wind output and raised gas demand from power stations. (confirmed by source) Reuters via Cyprus Mail, 10 Jan 2025
- The high all-day average (not just an evening spike) fits a day where gas plants set the price in nearly every half-hour. (inference)
Wider context that week
- On 10 Jan Centrica said UK gas storage was "concerningly low": 26% below the same point a year earlier, about half full, less than a week of demand. It blamed the cold, low wind and the end of Russian transit through Ukraine. The government said it was confident of supply. Centrica (page blocks automated access, not read directly) · Reuters via Cyprus Mail · Offshore Technology
- January's wholesale power average was £124.35/MWh, up about 20% on December, and NBP gas averaged 122.86p/therm, up 11%. Smart Energy UK January 2025 report
Confidence
Medium to high. The cause (cold, still, gas-heavy day) is solid from data and Reuters. What is missing is a report about power prices on this specific date.
Gaps
No article found quoting the day-ahead price for 10 Jan, and no NESO margin notice found for this date (searched; the notices reported were for 8 Jan). Could not read Centrica's own press release (HTTP 403), so its content is taken from Reuters and trade press.