Hydrogen vehicle

A hydrogen vehicle is a vehicle that uses hydrogen to move. 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.^[1]

Hydrogen burns cleaner than fuels such as gasoline or methane but is more difficult to store and transport because of the small size of the molecule. As of the 2020s hydrogen light duty vehicles, including passenger cars, have been sold in small numbers due to competition with battery electric vehicles.^[2][3] As of 2021^[update], there were two models of hydrogen cars publicly available in select markets: the Toyota Mirai (2014–), the first commercially produced dedicated fuel cell electric vehicle (FCEV),^[4][5][6] and the Hyundai Nexo (2018–).

As of 2019, 98% of hydrogen is produced by steam methane reforming, which emits carbon dioxide.^[7] It can be produced by electrolysis of water, or by thermochemical or pyrolytic means using renewable feedstocks, but the processes are currently expensive.^[8] Various technologies are being developed that aim to deliver costs low enough, and quantities great enough, to compete with hydrogen production using natural gas.^[9]

Vehicles running on hydrogen technology benefit from a long range on a single refuelling, but are subject to several drawbacks including high carbon emissions when hydrogen is produced from natural gas, capital cost burden, high energy inputs in production and transportation, 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.^[10][11][12] In addition, leaked hydrogen is an invisible, highly flammable gas and has a global warming effect 11.6 times stronger than CO₂.^[13]