Ah, but hydrogen has a very low volumetric energy density at ambient conditions, equal to about one-third that of methane. Even when the fuel is stored as a liquid in a cryogenic tank or in a pressurized tank, the volumetric energy density (megajoules per liter) is small relative to that of gasoline. Because of the energy required to compress or liquefy the hydrogen gas, the supply chain for hydrogen has lower well-to-tank efficiency compared to gasoline.