Okay, but gasoline is far more energy dense than batteries and a gas tank is a whole lot cheaper than a battery pack, so vehicles can have a gas tank big enough that that doesn't cause range problems. I don't know about buses, but you can buy a pickup with a 48 gallon tank. Even after assuming only about 1/3 efficiency, that's still equivalent to some 500 KWhr, which is several times more than any consumer EV I'm aware of.