A hydrogen vehicle is a vehicle that uses hydrogen fuel for motive power. Hydrogen vehicles include hydrogen-fueled space rockets, as well as 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 burning hydrogen in an internal combustion engine.
, 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. 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 CO₂.
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.
Vehicles
Rationale and context
The rationale for hydrogen vehicles lies in their potential to reduce reliance on fossil fuels, associated greenhouse gas emissions and localised air pollution from transportation. This would require hydrogen to be produced cleanly, for use in sectors and applications where cheaper and more energy efficient mitigation alternatives are limited.
Aeroplanes
Companies such as Boeing, Lange Aviation, and the German Aerospace Center pursue hydrogen as fuel for crewed and uncrewed aeroplanes. In February 2008 Boeing tested a crewed flight of a small aircraft powered by a hydrogen fuel cell. Uncrewed hydrogen planes have also been tested. For large passenger aeroplanes, The Times reported that "Boeing said that hydrogen fuel cells were unlikely to power the engines of large passenger jet aeroplanes but could be used as backup or auxiliary power units onboard."
In July 2010, Boeing unveiled its hydrogen-powered Phantom Eye UAV, powered by two Ford internal-combustion engines that have been converted to run on hydrogen.
Automobiles
, there are two hydrogen cars publicly available in select markets: the Toyota Mirai and the Hyundai Nexo. The Honda Clarity was produced from 2016 to 2021. Hydrogen combustion cars are not commercially available.
In the light road vehicle segment, by the end of 2022, 70,200 fuel cell electric vehicles had been sold worldwide, compared with 26 million plug-in electric vehicles. With the rapid rise of electric vehicles and associated battery technology and infrastructure, the global scope for hydrogen’s role in cars is shrinking relative to earlier expectations.
The first road vehicle powered by a hydrogen fuel cell was the Chevrolet Electrovan, introduced by General Motors in 1966.
The Toyota FCHV and Honda FCX, which began leasing on December 2, 2002, became the world's first government-certified commercial hydrogen fuel cell vehicles, and the Honda FCX Clarity, which began leasing in 2008, was the world's first hydrogen fuel cell vehicle designed for mass production rather than adapting an existing model. Honda established the world's first fuel cell vehicle dealer network in 2008, and at the time was the only company able to lease hydrogen fuel cell vehicles to private customers.