Electric cars could make their owners money while they sit idle Maskot Bildbyrå At least 90 per cent of the electricity generation being built today is renewable. But solar and wind farms produce electricity only when the sun is shining and the wind is blowing, so the power supply will fluctuate more. A pilot project in the US state of Delaware has shown that owners of electric vehicles (EVs) could make thousands of dollars each year by allowing their parked cars to serve as part of a giant col...