[Gibbon1]

My back of the envelope calcs say that if batteries energy density increases by 30-50% the weight penalty for electric cars disappears. It's a fuzzy line because it depends on the cars range.

Difference between electric and gasoline cars. With a gas car the marginal cost of extra range is low. With electric it's high. With gas cars the marginal cost of extra HP is high where with electric it's low.