None, nor electric cars. It is an industry in it's infancy that needs time to mature. Electricity is not an energy source it needs to be generated from energy sources--currently in the civilized world a modestly inefficient process to create AC current, we then carry it, with losses, over power lines to it's application where in the case of electric vehicles we convert it to DC--with losses-to charge batteries to convert that stored energy to motive force (with losses) Direct conversion of an energy source (gasoline) to motive force is modestly inefficient but still in the overall more efficient than all the conversion and transmission loses. In any valid "Well to Wheels" analysis, modern ICE's win every time...