What is a hydrogen fuel cell car and how does it work?

You might have heard the term hydrogen fuel cell car and wondered what it was. It’s an eco-friendly alternative fuel that's already on sale, and which some claim represents the future of motoring. There is certainly a growing shift for car makers to develop this new tech. But how viable is it? Read on to find out all about fuel cells.

What is a fuel cell car?

Imagine a car that could generate its own electricity to power a motor from a naturally occurring element. Broadly speaking, that is what a fuel cell car is: an electric car that is fuelled by hydrogen so doesn’t need to have its batteries charged from the mains.

The fuel cell and its control unit live where you’d find the engine in a combustion engine car and under the floor. The tanks that store the flammable hydrogen are heavily reinforced and located in the middle and towards the rear of the car. Other than that, it's a traditional looking car.

How does a fuel cell work?

The fuel cell induces a chemical reaction that splits the hydrogen molecules into positives and negatives. By mixing these with air taken from outside, they create electricity to power a motor. The by-product is water which is expelled from the car as vapour.  

Where do you buy the fuel?

You refuel a fuel cell car just as you would a petrol or diesel motor. You pull into a roadside filling station and pop the fuel filler flap. Because the hydrogen is pressurised, the pump has a special nozzle that attaches to the car. Once this is done, it takes about five minutes to refill the hydrogen tank, making it significantly quicker than charging a battery electric car.

Can you buy hydrogen in the UK?

Yes you can. The hydrogen is under pressure so you must fill up at a station, rather than charging at home as with electric cars.

The trouble is, the number of hydrogen filling stations is very limited. In March 2020, there are 14 in the UK. Six of those are in and around London. There is only one in Scotland (near Edinburgh) and the next closest to that is Sheffield. There are just two hydrogen stations between Sheffield and London.

Can you buy fuel cell cars now?

The UK’s hydrogen car market is currently in a state of flux. Although up until recently you could buy models from Toyota (the Mirai) and Honda (the Clarity), the only hydrogen car currently available is the Hyundai Nexo. And at £65,995 including the UK government’s £3500 zero emissions incentive, it’s expensive. But it is a luxury motor with heated and ventilated seats, heated steering wheel and a 12.3-inch navigation screen.

How expensive is the fuel?

Hyundai claims its Nexo has a range of 414 miles, which is better than an electric car. Hydrogen is bought in kilograms rather than litres or gallons. In early 2020, hydrogen’s cost per mile in fuel works out as roughly comparable with an internal combustion engine car.

Are hydrogen cars eco-friendly?

The cars are planet friendly because the only waste product from a hydrogen fuel cell is water. And manufacturers such as Hyundai reckon their cars actually clean the air as you drive along.

But critics claim hydrogen isn’t a particularly eco-friendly fuel. This is because although there’s plenty of it around, it’s usually part of another compound (such as water). And extracting it can be tricky and expensive. But the cost of doing so is coming down all the time.

Some hydrogen filling stations produce their fuel on site. But those that don’t must have the fuel delivered. And that means a diesel-powered tanker. However, supporters will say that a huge number of electric cars are currently charged using energy generated from fossil fuels...

Are fuel cells the future?

Japanese and Korean car companies certainly think so because their countries don’t have massive fossil fuel resources so are desperate to find viable alternatives. They’re not alone. At the moment, every major motor maker is working on hydrogen fuel cell models. Resulting developments should cause the cost of fuel cell cars to fall.

And the infrastructure is likely to grow too. Fuel giant Shell currently runs a handful of the UK’s hydrogen stations so its rivals are unlikely to be far behind.

While hydrogen is unlikely to replace battery electric vehicles, it could run alongside them in the medium to long term, rather as diesel does with petrol today.