Volkswagen's chief strategist Michael Jost predicts their vehicle-to-grid electric car batteries could open up a new business opportunity: selling their electricity back to the power grid during peak demand. Reuters reports: "By 2025 we will have 350 gigawatt hours worth of energy storage at our disposal through our electric car fleet. Between 2025 and 2030 this will grow to 1 terawatt hours worth of storage," Jost told journalists in Berlin. "That's more energy than is currently generated by all the hydroelectric power stations in the world. We can guarantee that energy will be used and stored and this will be a new area of business."

The German carmaker is not alone in looking into this field. German utility E.ON has been working with Japanese carmaker Nissan to develop so-called vehicle-to-grid services.