> so in winter when the sun doesn't shine, the only reliable energy comes from fossil fuels.

Sure but we also don't have to care. The production capacity is already there, the CO2 to build it has already been spend. It's only running it, that's adding to the badness. And if we do that for 5% of the year. Then we have gotten 95% of the way there.

But what it does is: 1) it makes fossil fuel based electricity extremely expensive (about 20x except for the fuel) and 2) it endangers secondary uses of those plants. We currently use a significant fraction of the coal-fired power plants (at least 5GW) mainly for their heat. And _those_ needs will need to be covered before we can really turn coal off. Nevertheless: Reducing fossil's capacity factor is a good thing and buys time for other bridges (e.g. power-to-heat and storage) to arrive.