Fuel cell technology has been in development since the late 1800s and hydrogen fuel cells have been around since the early 1930s. However, they have never been as widely discussed as they are today.
That's because the technology is almost at a stage where it can be employed in consumer vehicles on a mass scale, with refillable fuel cells able to drive electric motors and maintain zero emissions without needing to be replenished every 100-200 miles.
In short, it is the Holy Grail for sustainable car travel and, therefore, an ideal subject for Pocket-lint's sustainability month.
Here then is what we know about hydrogen fuel cell technology and whether it might feature in your next car.
What is hydrogen fuel cell technology?
A fuel cell is similar to a battery in some ways - it essentially provides an electrical current.
However, while a battery stores energy a fuel cell generates its own. It uses a fuel source - in this case hydrogen - which chemically reacts with the oxygen in the air to create an electrical charge. This electricity can then be used to power machinery or, in the case of consumer vehicles, either power the drivetrain directly or to top up a rechargeable battery that subsequently drives it.
And, unlike combustion alternatives, the waste products of the process are just a little heat and water (H2O). It is therefore a zero emission technology well suited to the future of clean, green travel.
Hydrogen fuel cell benefits
As well as zero emissions, hydrogen is a sustainable fuel in comparison, say, to fossil fuel alternatives. It is even ecologically friendly to produce.
Many hydrogen production plants run on solar or wind power and use electrolysis to extract it from water - seawater, even. This method has a very low carbon footprint and the gas released into the air during manufacture is simply oxygen.
The pure hydrogen produced this way is ideal for low temperature use, such as in fuel cells for cars.
Of course, not all hydrogen production plants are fully green and some still use fossil fuels as part of the process, but it is hoped that electrolytic methods can be ramped up in scale over time to ensure that the entire chain becomes as carbon zero as possible.
Another benefit to fuel cell technology over other low or zero emission rivals is that the cells can potentially produce a lot of power for relatively small devices. That means a car using hydrogen as a fuel source should be capable of travelling much greater distances than an all-electric equivalent.
Hydrogen fuel cell barriers
However, while there are obvious wins for using hydrogen as a fuel type for cars, there is one particular barrier that is preventing manufacturers from mass market hydrogen vehicle production at present: accessibility.
Unfortunately, even though the technology and hydrogen production facilities have been around for decades, the infrastructure is not in place to support consumer cars on a large scale. There is a distinct lack of refuelling points, basically.
There are only 16 publicly accessible refuelling stations currently available around the UK. And most of those are near London.
One of the largest UK hydrogen refuelling networks, ITM Power, is planning to install hydrogen refuelling capabilities in an additional three stations this summer, but that will still only result in 11 operable sites - which is far from enough to consider the fuel as a viable consumer option right now.
Another possible barrier is safety. Hydrogen is a highly flammable gas and its transport to and installation of safe storage solutions are both costly undertakings - at least initially. There are upsides in that it is non-toxic, unlike petrol and diesel, and dissipates quickly, but it needs to be handled with care which requires specialist equipment that the vast majority of conventional fuel stations do not currently support.
What hydrogen fuel cell cars are available now?
The lack of consumer accessibility is clearly a major barrier for car manufacturers. They are unlikely to invest heavily in production until the infrastructure is in place to support their vehicles.
However, there are a couple of commercially available options on the market already, from Hyundai and Toyota. And the BMW Group has committed to testing a hydrogen car prototype with one eye on the near future.
The Hyundai Nexo is one production car commercially available in the UK right now. While it will set you back just shy of £70K, its zero emissions rating allows it to be run tax-free.
That will be joined later in 2020 by the second-generation Toyota Mirai, which has a sleek design and potential range of up to 400 miles. That's thanks to an on-board battery as well as the hydrogen fuel tank and fuel cells.
Toyota has also partnered with BMW to provide the fuel cell tech for the German group's i Hydrogen NEXT concept, which is currently in the testing phase.
It will still be a while before BMW builds a production hydrogen car though: "At the earliest in the second half of this decade," the company said in a statement.
To be fair, these are still very early days for hydrogen fuel cell technology - at least for in-car use. And, it is likely we will have to wait several years yet before hydrogen fuel cell technology hits the magic blend of affordability and availability.
But thankfully, in the meantime, car manufacturers are committed to the continuing development of all-electric technologies, which should serve them in good stead until the real game changer fully arrives.