Its been a problem for a very long time now, electric cars require large amounts of electricity to charge and that needs to be supplied through the residential grid. Higher use of electric cars means more electricity necessary. Electric cars usage is still going up and that is not likely to change soon. As for the more important part: Lots of power plants are not green, and replacing them means building more power generators. This device converts heat to (green) electricity. How could you possibly see this as a negative?