You don't really want to power the entire vehicle. The question is more like, which is the most efficient wheel, which is the best aerodynamic shape and which i

You don't really want to power the entire vehicle. The question is more like, which is the most efficient wheel, which is the best aerodynamic shape and which is the most efficient roof. If you can have components with negative load it's all good. Say that 7-10kw / 60kw is 12% to 17% savings. 6-8mpg becomes 6.72-9.36 mpg Or for laughs one could say every 10th car requires no fuel.