Hydrogen vs. Battery Electric Cars

Note, there is no “free hydrogen” (i.e. hydrogen molecules that are not bound into some other chemical compound) on earth. You can make hydrogen by electrolysis from water using renewable power, but that’s much less efficient than charging a battery. Hydrogen would be a solution for air travel because batteries don’t have sufficient energy density (kWh/kg) to make electric airliners with more than about 1,000 miles range feasible. Hydrogen has its own storage problems because a hydrogen powered airliner would need cryogenic H2 and even this has less volumetric energy density than conventional jet fuel (highly refined kerosene). Most H2 is currently made from natural gas (methane) which releases significant CO2. Fuel cells are, currently, expensive and the fuel cell stack, with current technology, has to be rebuilt every few years.