Comment by nobodysfool

Well, one of my friends in Arizona has not necessarily his whole roof covered, but he is able to generate about 90% of his yearly energy usage. The only problem is that he doesn't have batteries installed, so he's selling his electricity to the local power company and buying it back. With batteries and a slightly larger system, he'd meet all his energy needs himself. It's definitely possible. One thing that helps is the hot water heater is solar powered as well.