You also need power to heat, and there's usually very little sun then... sometimes even no wind. Nuclear and thermal are both slow to ramp up and ramp down, an

You also need power to heat, and there's usually very little sun then... sometimes even no wind. Nuclear and thermal are both slow to ramp up and ramp down, and unusable for short term peaks. Hydro is actually great for that, because you can regulate the power production relatively fast (as long as you have enough water).