Hydrogen cars: how do they work?

All you need to know about hydrogen fuel cell cars. How to buy, where to fill up and running costs

By Nick Gibbs, John Evans, BuyaCar team

Hydrogen fuel-cell cars are the missing link between the cleanliness of an electric vehicle (EV) and the no-hassle, go-anywhere range of a regular car with a petrol or diesel engine.

You can fill up the tank like a regular car, drive for up to 350 miles and then spend as little as three minutes filling it up with hydrogen again.

But instead of potentially harmful gases escaping from the tailpipe, the only waste product is pure water. Sounds great, doesn’t it? So what’s the catch?

Can I buy a hydrogen car?

The two biggest companies offering hydrogen-powered cars in the UK are Toyota and Hyundai.

Neither cars are cheap. If you were to offer hard cash, Toyota's hydrogen car, the Mirai (pictured), will cost you £62,500 after the £3,500 low-emission vehicle government grant, while the Hyundai Nexo, due to be launched in March 2019, will cost around £65,500 after the grant.

This model replaces the Hyundai iX35 FCEV (fuel-cell electric vehicle), the first hydrogen car in the UK which was launched in 2015 and which new, cost £53,105. Unlike that car, it is a dedicated hydrogen-powered car rather than being adapted from an existing design. It’s also right-hand drive and thanks to its larger 6.3kg hydrogen tank has a range of 414 miles. 

Both models are best suited to fleet users and taxi companies operating close to the few refuelling points that exist and which lease their vehicles. The Toyota, for example, costs £750 a month including all fuel and servicing on a four-year or 60,000-mile term. You can lease it as a private individual but the few Mirais on the road (by early 2019, three years since the model’s launch, there were just 90 but 7,600 worldwide) are mainly operated by companies and organisations ranging from the Metropolitan Police to car hire company Green Tomato Cars which has 50 hydrogen cars.

A spokesman for Toyota explained that at this early stage of infrastructure development, the Mirai suits business users with a defined operation in areas with better fuel station coverage. “We have concentrated the limited production volume on customers that is suits best,” he said.

Hyundai says it will offer the Nexo to private customers and forecasts it will sell around 50 per year in the UK. This compares with the 17 ix35 FEV models it sold.

Meanwhile, it is possible to lease a Renault Kangoo ZE-H2 electric van with a fuel cell range extender produced by Symbio FCell. A Welsh-based company, Riversimple, has also produced a prototype hydrogen car called the Rasa, which is designed to be light, efficient and cheap. It plans to build a four-seat version and a van, but this depends on the company attracting enough investment.

What about other car makers?

Kia plans to launch a Sportage-sized hydrogen car based on sister company Hyundai’s Nexo, in the second half of 2020.

There would be more new models to choose from but car makers say the UK’s refuelling infrastructure is not sufficiently well developed to justify selling them. Honda used to sell the Clarity FCV in the UK but after just three sales it withdrew it and now offers it for lease only in California and Japan. Mercedes sells its GLC F-Cell in mainland Europe and has no plans to introduce it to the UK.

Audi, which is the project leader for hydrogen cars in the Volkswagen Group, has shown a prototype hydrogen-powered SUV called the h-tron quattro, but says its focus is now on battery electric vehicles.

Where can I fill up a hydrogen car?

There are just 13 publicly available refuelling stations in the UK. They work much like petrol stations. You drive up, attach the fuel hose (unlike electric charge points, the nozzle has been standardised across vehicle manufacturers) and fill the tank. The fuel is dispensed at a pressure of 700bar for passenger cars and 350bar for commercial vehicles including buses.

Hydrogen stations operated by ITM Power, the largest operator, produce hydrogen on site, rather than having it delivered by tankers. Those stations operated by Air Products, part of BOC, do have it produced off-site and delivered.

The refuelling network is small and concentrated around London but is growing, slowly. In February 2017, ITM Power opened the first motorway services hydrogen filling station on a Shell forecourt on the M25 in Cobham, Surrey. Like ITM’s other sites, it produces hydrogen on-site and is designed to use surplus electricity from wind farms that is not needed when generated. ITM says that as demand for the fuel increases, it will simply increase the size of its storage tanks and generation systems at each site to meet it.

Its Cobham site joined four other public ITM sites in London, one in Swindon, Wiltshire and another in Rotherham, South Yorkshire. During 2019, the company will open more public refuelling stations, one each in Gatwick and Birmingham, and two in Derby, taking its network to 11. With the addition of BOC Air Products’ two stations, that takes the total number to 13.

A government-funded consortium called UKH2Mobility, which is pressing for greater use of hydrogen as a road fuel, says that there are plans for 65 filling stations by 2020 and 1,150 by 2030.

In contrast, at the end of 2017 there were 8,422 regular filling stations in the UK, according to the latest figures from the UK Petroleum Industry Association. Clearly, finding the fuel to put in your hydrogen car will remain a problem for some years yet, even in the most optimistic scenario.

How do hydrogen cars work?

Fuel-cell cars are essentially electric cars in which the electricity is generated on board via a chemical process.

This happens in the fuel-cell ‘stack’ where oxygen from the air around us and hydrogen from a storage tank in the car are mixed in such a way as to release electrons from the hydrogen.

This electricity is used to power an electric motor. The reaction prodces water, which is channeled away outside the car. The power produced is roughly similar to standard combustion-engined car, so the Hyundai has an 136 horsepower (hp) electric motor while the Mirai produces 155hp.


How much does a hydrogen car cost to run?

Toyota claims the range of the Mirai (above) is 340 miles from the 5kg of gas held in the tanks (gas is measured in kg rather than litres). When we spoke to a Mirai taxi driver, he said he was getting around 280 miles on a tank, or less when it’s cold.

With 1kg of hydrogen costing around £12, the cost of filling up a Mirai is £60 and a Nexon, which has a 6.3kg hydrogen tank, £72. In other words, it’s about the same price as an equivalent petrol car and provides roughly the same range. It equates to around 18p a mile based on real-world figures, compared to the 2p per mile estimated for electric cars. However the cost of hydrogen is likely to come down the more is produced.


Is hydrogen really going to be fuel of the future?

The £23m of government funding, announced in March 2017, is expected to provide some of the facilities needed for hydrogen cars to be a viable option for normal car drivers.

"We know availability of hydrogen refuelling infrastructure can be a potential obstacle to the take up of hydrogen fuel cell electric vehicles," said John Hayes, a transport minister. "That’s why we’re providing support to give interested parties the confidence to continue to invest in this new emerging technology to help us achieve our ambition for almost all new cars and vans to be zero emission by 2040."

Car manufacturers are split, though. In the ‘pro’ camp, Toyota is extremely confident. Its European CEO Johan Van Zyl recently declared the Mirai to be the new Prius and said it was inevitable we’ll eventually switch to using the fuel.

“We forsee EVs for short journeys, hybrids for all-round usage and fuel-cells for medium to long-range driving. But we see hydrogen as the long-term solution,” he said back in June this year.

Toyota believes hydrogen is the fuel of the future partly because it can be made using energy from the wind and sun. This effectively stores that energy for later use. At the moment, electricity from solar and wind must be used straight away, whether it's needed or not.

Fuel-cells are already powering other devices. Some submarines use hydrogen for example, as do the fork-lift trucks operating in BMW’s SUV factory in Spartanburg, US.

Hyundai can afford to build expensive fuel-cell cars partly because it can use the technology throughout its vast industrial empire to power boats, buses and submarines. However other makers aren’t convinced, citing the huge cost of the fuel-cell stacks themselves and the difficulty in persuading fuel firms and governments to invest the vast network of filling stations needed.

“My personal opinion is that hydrogen is tomorrow’s technology and always will be,” said Andy Palmer, currently CEO of Aston Martin and previously a top executive at electric-car advocate Nissan.

What could hasten the take-up of hydrogen cars?

ITM Power is confident that the roll-out of clean-air zones in the UK’s major cities and mounting pressure on car makers to reduce CO2 emissions will help raise awareness of the fuel and boost demand for cars using it. Having refuelling points under the forecourt canopy alongside petrol and diesel, as is the case at ITM Power’s new refuelling point at Shell Beaconsfield, will help, too, it says. However, one of the biggest barriers remains the cost of the hydrogen cars themselves and until prices come down, take-up will be low.

Are hydrogen cars safe?

Whatever the questions surrounding hydrogen, the one concerning safety has largely been answered. Every year around 2000 tonnes are safely transported on UK roads, according to UKH2Mobility, and if it does leak it quickly rises upwards and thins out because it's lighter than the air around us.

Toyota said it designed the Mirai to be as safe as possible, with sensors to shut off the tanks’ valves if leaks are detected. The car itself has been designed to direct crash forces away from the tanks, it said.

The company also says that as of 2019, at least two of its Mirais in service as taxis in London have each clocked up 70,000 trouble-free miles. Euro NCAP has awarded the new Hyundai Nexo its full five stars for crash safety.   

Are hydrogen cars really ‘green’?

One drawback of hydrogen is that it uses more energy to make than it subsequently delivers. This is also true of electricity, but both are good energy carriers and that’s their key appeal as a road fuel.

Hydrogen is a clean fuel in that cars that use it aren’t chucking out the same tailpipe pollutants as diesel or petrol equivalents, but its ability to cut CO2 does depend on what fuel is being used generating the electricity needed to create it in the first place.

Hydrogen production is well paired with renewable energy however, which might go to waste otherwise, for example from windfarms at night.