By Paul Homewood
A very disturbing report from Timera:
Heat wave leads to second summer GB Capacity Market Notice
A second GB Capacity Market Notice (CMN) of Summer 2022 was issued on the 11th of August at 13:34, as National Grid’s forecast of surplus capacity over the evening peak fell below the required 500MW 4 hours ahead of delivery.
In addition to their de-rated margin forecasts, National Grid publish their forecast loss of load probability at midday on the day before delivery, before subsequently updating at 8, 4, 2 and 1 hours before delivery. The above chart shows these forecasts for the evening peak on the 11th August. Loss of load probability (LoLP) gives an indication of the scarcity of available generation capacity for each settlement period, and would sit at 0% on a comfortable, well-supplied day. As delivery time approached on the 11th, availability improved, LoLP dropped significantly and the CMN was cancelled.
Despite the eventual cancellation, CMNs in summer months are vanishingly rare, and are typically used to manage winter peak demand. In the record-breaking heat this summer, demand for cooling has been strong and some generators across the UK and the Continent have struggled in the high temperatures (e.g. challenges for cooling for French nuclear plants, barging coal to southern German coal plants and low hydro). These factors, when combined with low wind (around 2GW on 11th August), are likely to have caused the tight margins leading to the CMN.
For a start, forget about the misdirection about “heatwaves”, as if this was the cause. Demand peaked at 31.4 GW on August 11; As the chart for July shows, most days in summer, other than weekends, peak well above 30 GW:
As Timera comment, to even get close to scarcity of power in summer used to be unheard of.
The real cause was simple, low wind power, down to 2.5 GW during the evening peak demand that day (light blue on the chart below):
As for solar, this had all but disappeared by 7.30 pm:
https://www.solar.sheffield.ac.uk/pvlive/#
The problem was easily resolved in the end, by firing up CCGTs, which ramped up from 14.4 GW at 4.30pm to 16.4 GW three hours later:
https://www.bmreports.com/bmrs/?q=eds/main
It is also worth noting that CCGT actually peaked at 9.30pm, because we were quickly running out of pumped storage, which had been used up earlier in the evening, and reduced interconnector supply.
Also note that coal was still supplying 0.4 GW throughout the afternoon and evening!
How much longer we can rely on gas and coal is another matter.
via NOT A LOT OF PEOPLE KNOW THAT
AUGUST 15, 2022
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