Umm, so we still have to build enough traditional (and, ideally, dispatchable) generation capacity to make sure we can cover our electricity needs during those periods in winter where it's very cloudy and it's not windy?
eg Jan 2025
https://www.theguardian.com/money/2025/jan/22/weather-bomb-e...
"Cloudy and still weather has caused Great Britain’s renewable energy output to fall to near zero this week"
"Britain’s wind power output fell to just above zero on Wednesday, which, combined with the cold, dark weather, caused the market price for electricity to climb to almost £250 per megawatt-hour at auction, or almost seven times the average price before the pandemic"
"The sudden drop-off in renewable energy due to dull windless winter weather, known as dunkelflaute in German, has also forced the system operator to pay gas power stations more than £500/MWh to run on Wednesday evening when household demand is expected to reach its peak.
The weather conditions – the third dunkelflaute of the winter so far – left Britain’s electricity grid reliant on gas-fired power stations. They accounted for more than 70% of power generation at points on Wednesday."