[izacus]

> Every time I saw this kind of discussions, my first question is, what happens when sun is not shining? Like in the night or when it's very cloudy?

What's been happening now in Europe - the electricity prices go negative during the day and in the evenings the gas plants are turned on and start burning fossil fuels again to make up for the demand.

Luckily in some places it's supplanted by wind (when available - e.g. Germany), but a lot of EU countries just burn gas in those examples.