Elon Musk talked about how BTC mining with electricity isn't environment friendly but he invented electric cars, in near future if this actually becomes popular electric cars will be available world wide and billions of vehicles will be charged by electricity so how is this environment friendly?
Because you can produce electricity with solar cells while you can't produce fuel with solar cells. The long term vision is that all energy these cars require comes from renewable energy sources like solar panels and what not. But his batteries are not as environmental friendly as many would think as far as I know. There are still some ifs involved.