I’ve argued ad nauseam that battery-electric propulsion is poorly suited for most full-scale aircraft applications. To deliver a certain amount of power for a certain length of time requires a weight in batteries 15 times that of conventional fuels. Batteries may serve for flights at low speeds over short distances, such as an hour of student instruction, but they don’t lend themselves to passenger- or cargo-carrying trips of many hundreds of miles at hundreds of miles an hour. For that, you need fuel.
Among potential aviation fuels that are not hydrocarbons like gasoline and ethanol, hydrogen is currently the most promising. Seated at the head of the periodic table, hydrogen is the lightest element, a minimalist atom consisting only of a proton and an electron. It is not scarce: three-quarters of the mass of the universe is hydrogen. Hydrogen contains lots of energy—about three times as much, per pound, as gasoline. In that respect, it’s at the opposite end of the spectrum from batteries and far ahead of any hydrocarbon fuel.
