Thousands of windmills were built on both sides of the Columbia River. When driving along ithe river it would be a big surprise to see even half of them turning. They are tied into the real producers of electricity the Dams, and they are always producing. they use the same power lines and windmills have no way to "store" power, so depend on the Dams, when they are not working. Dams also use "renewable" energy to produce...water.