Domestic water energy storage

Executive summary: Time domestic water pumps for periods of low electricity demand.

Problem: Wind energy has a large weakness that is difficult to overcome - energy is only generated when the wind is blowing. This is especially problematic when you need energy and the air is still. The common solution is to use other forms of energy on still days, but this generally results in burning coal, natural gas, oil, and other greenhouse gas creating resources.

One solution: A great way to make use of wind energy is by storing it when it's not needed and using it when it is. However, there are not many good ways of storing energy. Water energy storage is the most cost effective way to store energy. This consists of two lakes - one high on a mountain, one low in a valley. Water runs turbines when energy is needed, filling up the lower lake. When energy is not needed these turbines run in reverse, pumping water back up to the high lake.

The problems with this solution are that you need appropriate geography and it can be destructive to environments due to the rapidly changing lake levels. Also, although this is the most cost effective form of energy storage, it can still be quite expensive to build two manmade lakes.

My solution: Most towns and cities pump water up to water towers in order to provide domestic water at a constant pressure. Instead of pumping water to these water towers every time the level is low, pump water every time energy demand is low. This will effectively make domestic water storage into a distributed water energy storage system. Water towers don't currently know or care when energy is abundant or scarce - they turn on when water reaches a certain level. If we instead top off the tanks every slow-wind period, we're using unused energy to pump water and not using peak energy. A nice benefit of this system is that we don't need any additional construction - just a bit of control changes in water systems.