Hydrogen vehicle
A hydrogen vehicle is a vehicle that uses hydrogen to move it. Hydrogen vehicles include some road vehicles, rail vehicles, space rockets, forklifts, ships and aircraft. Motive power is generated by converting the chemical energy of hydrogen to mechanical energy, either by reacting hydrogen with oxygen in a fuel cell to power electric motors or, less commonly, by hydrogen internal combustion.
Hydrogen fuels many rockets and burns cleaner than other fuels such as methane, but requires larger tanks. Hydrogen aircraft are not expected to carry many passengers long haul before the 2030s at the earliest.
As of 2019, 98% of hydrogen is produced by steam methane reforming, which emits carbon dioxide. It can be produced by electrolysis of water, or by thermochemical or pyrolytic means using renewable feedstocks, but the processes are currently expensive. Various technologies are being developed that aim to deliver costs low enough, and quantities great enough, to compete with hydrogen production using natural gas.
Vehicles running on hydrogen technology benefit from a long range on a single refuelling, but are subject to several drawbacks: high carbon emissions when hydrogen is produced from natural gas, capital cost burden, high energy inputs in production, low energy content per unit volume at ambient conditions, production and compression of hydrogen, the investment required to build refuelling infrastructure around the world to dispense hydrogen, and transportation of hydrogen. In addition, leaked hydrogen has a global warming effect 11.6 times stronger than COâ‚‚.
For light duty vehicles including passenger cars, hydrogen adoption is behind that of battery electric vehicles. A 2022 study found that technological developments and economies of scale in BEVs, compared with the evolution of the use of hydrogen, have made it unlikely for hydrogen light-duty vehicles to play a significant role in the future. As of 2021, there are two models of hydrogen cars publicly available in select markets: the Toyota Mirai (2014–), which is the world's first commercially produced dedicated fuel cell electric vehicle (FCEV), and the Hyundai Nexo (2018–). There are also fuel cell buses.