Wall Street Journal ECOnomics Panel that he has solar panels on his house that power his electric car.
Five years ago, he put solar panels on his roof, and he has a chart of his monthly electricity bill before and after. By this time when adding up the savings, he not only paid for what it cost him but also the opportunity cost of the money he invested. He's driving an electric car, and the electricity used is far less than the solar panels produce. "It's free."