In case you're wondering how green your country's energy is overall, or how it fluctuates with demand and supply and night and day, have a look at the electricity maps here. It's quite interesting - and yes, France is very green because of low CO2-emissions from their nuclear powerplants. But there's still the issue of the material you need to get them running, the incredible cost of building them, and the tiny little detail of how to handle both the ruins once they are out of order, and the nuclear waste left over.
If you ask me, I'd prefer solar and wind energy...