Hydrogen cars: a solution for the future?
What is hydrogen, and how is it produced?
Hydrogen, or H₂, is a gas that is present in the atmosphere, but only at a rate of 0.000072%! However, despite its scarcity, this element is an almost infinitely renewable source of energy. Natural and non-polluting, hydrogen has been used since the beginning of the 19th century to power the engines of certain cars via a fuel cell.
The problem with hydrogen is that it is never present on its own but is systematically linked to other elements. Several methods are used to isolate it:
- production from fossil fuels: this is known as grey hydrogen (or blue hydrogen if a large proportion of the emitted CO₂ is captured),
- electrolysis of water using electricity produced from renewable resources: this is called green hydrogen.
Therefore, the overall environmental impact of hydrogen-powered mobility depends very much on the origin of the hydrogen used.
How does a hydrogen vehicle work?
There are two main operating principles: the fuel cell and the hydrogen engine. The first involves electric cars, in which the conventional lithium battery has been replaced by an electrode, where a chemical reaction will occur. The oxidation of hydrogen with oxygen produces electricity.
In the second case, the engine uses the energy produced by the combustion of hydrogen and oxygen, while the water resulting from this reaction drives the engine pistons.
The advantages and disadvantages of a hydrogen vehicle
In theory, these vehicles represent an ideal solution from an ecological point of view, but the reality is sometimes different in practice.
The advantages of using hydrogen as an energy source for cars include:
- the use of renewable energy
- no CO₂ or greenhouse gas emissions when using the car
- smooth and quiet driving
- a longer range: over 600 km
- fast recharging time, equivalent to a full tank of petrol
On the other hand, hydrogen vehicles also have disadvantages, including:
- limited engine power
- a higher purchase price (2 to 3 times higher than a combustion car)
- an extremely limited number of recharging stations in the UK (only 15 stations as of 2022)
- the carbon footprint depends on the method of production of the hydrogen
- flammability that makes this gas potentially dangerous
Conclusion: should we start now?
Although potentially very interesting, hydrogen is not yet a ‘mainstream’ solution. In the UK, this type of engine is mainly used by buses: with only about 300 hydrogen vehicles on UK roads!
Hydrogen faces major challenges on many levels. First of all, 95% of the current extraction process is based on fossil fuels: nonsense for renewable energy! Secondly, as well as its extreme flammability, there is the problem of storing and distributing hydrogen. All these elements combined explain both the prohibitive cost of vehicles equipped with hydrogen and the low development of this technology.
The UK Government’s Hydrogen Strategy, unveiled in 2021, concentrates on busses and heavy goods or long-haul vehicles, in addition to Hydrogen Transport Hubs in the Tees Valley and Holyhead. Therefore, it might be preferable to wait and see how the sector develops over the next decade before thinking about taking the plunge for your personal vehicle.