You can understand why the idea of a hydrogen-powered car is appealing. Humans aren't great at accepting change, but we do find comfort in the familiar. Being told that our transport must decarbonize means more change. While electric vehicles are better at almost everything, even the world's biggest EV evangelist must concede that charging a car takes longer than filling a fuel tank. Hydrogen can be pressurized and pumped, and hydrogen can be clean, therefore hydrogen-powered cars make sense, the argument goes.
That's probably all the prompt any regular Ars Technica reader needs to list the reasons why hydrogen is a non-starter. Like mammals after the Chicxulub asteroid, battery electric vehicles are poised to fill the niches soon to be left by the dinosaurs, in this case fossil fuel-powered vehicles, leaving alternative fuels like hydrogen evaporating into thin air.
But don't count the universe's simplest molecule out just yet. While it's unlikely to catch on in the near future for light passenger vehicles, there are commercial applications like trucks, trains, and other heavy equipment where it does make sense. (For this entire article, we're talking about green hydrogen, made of wind or solar energy; using fossil fuels to make hydrogen—even with carbon capture—offers little to no benefit. Unfortunately, the vast majority of hydrogen currently produced is derived from hydrocarbons.)
Burning hydrogen in an internal combustion engine is probably the most straightforward in terms of existing tech—after modifications to the engine and fuel system, the rest of the car's powertrain remains the same. And the only exhaust product is water. But hydrogen has little energy density, with just a single covalent bond between two atoms to be broken. Hydrogen combustion engines also make little power, and very inefficiently compared to a similar engine burning gasoline.
