Comment by otherme123

But my point is that you don't need additional generation. At night, a lot of wind energy is currently being lost, because 1) it doesn't get consumed and there's no means to store it and 2) the more eolic you install without batteries, the less ROI you get. Thus, you have to install extra-capacity for the day in the form of gas or coal. Now imagine you install batteries to store night wind energy: the show changes! You can actually replace a coal plant with a battery that can store enough wind energy at night that offset the coal plant, without extra generation installed.

This currently isn't true, because grids are not dumb. They are not over installing eolic or PV if they can't store the over production. But if batteries are price competitive, they might go that route. An eolic turbine that was previously stopped 50% of the nights, could be producing 24/7.