I was listening to a recent Science Friday episode where the benefits of windpower were being debated. One of the drawbacks mentioned was that wind energy is intermittent, often present at off-peak periods-and there is no good way to bank electricity for later. Well, at a national scale. Solar installations, like the Luz generation plants or Solar One which bank solar thermal energy in oil or water underground, to power turbines later.
There are batteries, of course, at a local and homestead scale. Batteries are somewhat expensive. However more common are refrigerators. I don’t see why surplus evening power wouldn’t be ideal for running freezers. This would allow an evening power input to go into icemaking and using that banked cold, lower the operating load of freezers during the daytime.
Heat exchangers, better yet. If freezers and hot water heaters were part of a common heat exchange system, then there would also be warm water for the morning. At a community scale, a neighborhood butcher’s freezer would serve as a kind of energy bank. Here is a Sci Am article discussing ice generation as a method of power storage.