Vehicles powered by hydrogen are a green alternative to electric vehicles and are more attractive for long journeys. And with the UK planning to ban petrol and diesel cars and vans in 2040, these vehicles will be increasingly important in the future.
They are powered by hydrogen fuel cells. A hydrogen fuel cell brings together hydrogen fuel and oxygen from the atmosphere and combines them through a series of chemical reactions to produce water and electricity. Unlike an internal combustion engine, a fuel cell produces little heat and no carbon dioxide or other harmful emissions.
The first fuel cell, invented in 1838, was not based on hydrogen and the concept was not a commercial success until the invention of the hydrogen–oxygen fuel cell in 1932.
Hydrogen fuels cells are ideal for powering vehicles. Unlike battery-powered electric vehicles they do not have to carry heavy expensive batteries which are difficult to recycle, they do not take hours to refuel and have the same sort of range as conventional vehicles.
Generating the hydrogen fuel can be a problem however. Depending on how it is generated it can produce pollution including greenhouse gases. One of the worst ways is to generate it from natural gas, but even so the vehicles which use this type of hydrogen produce 30% fewer emissions than conventional vehicles.
Luckily there are other ways of generating hydrogen which produce far fewer emissions. The best way is by using electricity to split water into its component parts of hydrogen and oxygen (a process called electrolysis). In this case the only pollution is that which was created to generate the electricity, and green energy produces almost no emissions.
Hydrogen is sometimes considered to be dangerous because it explodes when mixed with air and ignited. But petrol and diesel are also capable of exploding and the average petrol tank holds three or four times as much energy as a hydrogen vehicle. In addition hydrogen is very light so any that if it escapes because of a burts tank it rapidly dissipates, whereas petrol forms pools on the ground which are more dangerous. And because the hydrogen is pressurised the tanks are stronger than normal fuel tanks.
The benefits of ownership include the fact that owners won’t have to pay any vehicle excise duty (road tax). However there is a £310 annual charge for cars over £40,000 for the first five years. Also they are exempt from the London congestion charge.
The greatest problem with hydrogen vehicles is that currently the number of hydrogen refuelling stations is limited. There are only about 20 within the UK. Luckily Coventry University has one of them! Note we have not verified whether it is still in operation or open to the public. It was intended primarily to fuel a fleet of hydrogen-powered vehicles built by Microcab, a Coventry University spin-off company. The UK government aims to have 65 stations open to the public across the UK by 2020.
Another problem is that hydrogen is more expensive than petrol or diesel. The cars are expensive too, upwards of £50,000 and servicing can be a problem.
We believe that currently the Toyota Mirai, Hyundai ix35 FCEV and Honda FCX Clarity/FCV Clarity are available.
In addition to hydrogen cars, the UK government is currently running the £20 million Low Emission Freight and Logistics Trial. The aim of the competition is to demonstrate new technologies and to encourage the widespread introduction of low and zero emission vehicles to UK fleets.