The race towards efficiency in the automotive sector has seen many OEMs focusing their efforts on battery-electric vehicles. But, with recent announcements from Toyota, Hyundai and BMW of investments in hydrogen fuel-cell cars, it seems that this new technology is hot on the efficiency trail.
However, whether the automotive industry is ready for hydrogen is debatable. By 2020 there will be 65 hydrogen filling stations in Britain, concentrated in the busiest areas, according to a recent estimate from the government and industry. But despite the recent hydrogen push, there are even fewer hydrogen refuelling stations than there are electric car charging points. As it stands, Britain has only four hydrogen filling stations that are fully open to the public. The number is expected to grow to 13 this year, compared with a public electric charge point infrastructure of more than 3,700 locations.
Apart from the current scarcity of refuelling points, there is a case for a great future for fuel cells. Fuel-cell cars share the significant benefits of battery-electric vehicles, including zero tailpipe emissions and a cleaner fuel source. More importantly, they don’t share some of the main drawbacks of EVs, including limited range and having to wait for the battery to charge.
Start-up investment
And it is not just the large manufacturers that are investing their time and money in fuel-cell cars. A recent push for the technology has come from a small start-up firm from Llandrindod Wells in mid-Wales – the country where the inventor of the hydrogen fuel cell, Sir William Grove, was born. The firm, Riversimple, believes its prototype hydrogen fuel-cell car could change the way we buy and run cars in the future.
The car is the result of a 15-year project by Riversimple. The project has recently been taken to the next stage with the launch of the first production-ready, road-legal prototype and the start of a public trial of the car – called the Rasa, after the Latin tabula rasa, meaning clean slate.
PE met Riversimple’s founder, Hugo Spowers, to see the Rasa and discover why the company believes the car could change the industry’s attitude towards fuel-cell vehicles. “The Rasa engineering prototype marks a milestone in bringing an affordable and efficient hydrogen-powered car to market,” he says. “We really have started from a clean sheet of paper with this car.”
The main reason for this, says Spowers, is that the start-up company has an edge over large manufacturers in that it can design the car under no constraints and with no specific rules. “We understand why the auto industry is doing what it’s doing in regards to fuel-cell development, but we as a start-up have the advantage of being able to design a car completely differently, and we’re not bound by the manufacturing capacity we have.”
The Rasa works by passing hydrogen through the fuel cell, where it combines with oxygen to form water and electricity to drive motors positioned in each of the four wheels. “When the car brakes, the kinetic energy that is normally lost in the form of heat is captured as electricity,” says Spowers. As the vehicle slows, the electricity floods into a bank of super-capacitors at the front of the car. Unlike a battery, these super-capacitors can take a huge charge quickly, but they don’t store a lot of energy. The energy they take in is sent back to the motors again and provides the power to accelerate.
“This innovative network design means that we only require a fuel cell big enough to provide cruising speed power, rather than acceleration,” says Spowers. “We are getting more than 50% of the braking energy back, which is used to boost acceleration.”
The production prototype of the Rasa was designed by Chris Reitz, former design chief of the Fiat 500, and his team at their studio in Barcelona. The Rasa was purpose designed from the ground up and built with ‘ultimate vehicle efficiency’ in mind, says the company.
As with all hydrogen cars, Riversimple’s Rasa has no tailpipe emissions. The well-to-wheel carbon dioxide output using hydrogen made from natural gas is around 40g per km, which the company claims to be the lowest of any vehicle available, says Spowers. “But with rapidly improving drivetrains and refined production methods, we expect to be able to cut that number, potentially in half, in the coming years,” he adds.
Lightweight materials
The car uses an 8.5kW hydrogen fuel cell rather than the 85kW fuel cell used in other hydrogen vehicles, such as those offered
by Toyota and Hyundai. The fuel cell used is the same size as ones used in forklift trucks and generates 11bhp (8.23kW).
With a carbon composite chassis and glass-fibre body panels, the Rasa weighs 580kg and is said to be capable of 250mpg (88.5km/litre) on the official urban cycle. “This is achieved through the use of lightweight materials and advanced aerodynamics,” says Spowers. “The bodywork and curved underbody create a drag co-efficient of just 0.224 – lower than any production car on sale today.”
And there are still some aspects and features in which the company can reduce weight further. “One thing in particular is the motors,” he says. “They’re very efficient at about 12kW each but they are particularly heavy. They weigh around 20kg each and our target weight was 12kg.”
Spowers argues that hydrogen is “head and shoulders ahead of everything else when you look at the range we have become accustomed to – it’s just that petrol engines are versatile and we’re lazy, so we use them for everything and they do everything inefficiently”.
“People talk about powertrain efficiency in a battery-electric car, and that batteries are 90% efficient and fuel cells only 50%, which is true. But we aren’t interested in powertrain efficiency –we are interested in overall vehicle efficiency. You can build an efficient battery-electric car with a high powertrain efficiency but a low vehicle efficiency.”
But the future of automotive efficiency does not lie simply with fuel cells or battery-electric cars – he sees a role for both, he says. “This isn’t an either-or situation. We need a much more complex mix of powertrains in the future, and this lies with a mixture of both electric and fuel-cell technologies.”
The company intends to market the Rasa in 2018 through a sale-of-service scheme whereby, for a fixed monthly fee and distance allowance, Riversimple will provide all repair, maintenance, insurance, and fuel costs. “As a result, drivers will not own the car, but simply swap it for a new one or return it at the end of the use period,” says Spowers.
This approach will help reduce the financial burden of outright vehicle ownership for the average driver, claims the company. “The Rasa gives us the opportunity to introduce customers to a lightness of ownership that neither places a burden on the pockets of motorists or the environment.”
Riversimple is keen on sharing, and plans an open-source approach to its technology and components to encourage economies of scale in its sector, says Spowers. “We will also open-source all its findings and development, so other companies can then work to develop the technology. We want to open-source the technology and for people to copy us. I am confident that our place as development leader will ensure our survival, even if the technology is used elsewhere.”
The company is aiming to reach 5,000 units a year, which Spowers describes as a relatively small segment of the market. “We have to get to that unit before the car is profitable,” he says.
Later this year, following funding to match a £1.6 million EU grant, the company will conduct a 12-month trial of 20 Rasa prototype cars as part of the continued development of the first full production model, which will come to market in 2018. The car will be offered to people in a phased roll-out by region, to support a low-risk, commercially practical introduction of profitable hydrogen refuelling infrastructure.
“Rather than trying to make money from customers in the first few years of ownership, we give the customer the most affordable service we can,” says Spowers. “If the car is cheap to build as well as being efficient and reliable, we make more money, and the customer is happier. All parties are working towards a common goal.”
Dual fuel plan
The initial batch of vehicles will use a hydrogen refuelling station in a yet-to-be-announced location, where Spowers hopes to some day sell hydrogen and electric capabilities. “Ideally, we would like both powertrain offerings in the same site,” he says. “I haven’t heard of that happening anywhere, so we have the potential to lead the industry with this offering.”
He believes the Rasa has the potential to change attitudes towards fuel-cell cars. But the infrastructure the car will have to rely on, as with other fuel-cell vehicles, still remains a thorny issue. To combat this, the vehicle will be marketed as a ‘local car’, to be used within a 25-mile (40.23km) radius of a hydrogen filling station. From one fill-up, the car can cover 300 miles – so the average customer should need to fill up only once a week.
“There needs to be a viable filling station network build,” says Spowers. “However, our car bypasses this problem by being a local car. Local cars are something nobody is building, but they are going to emerge and will persist. We are looking forward to seeing our Rasa make fuel-cell vehicles a viable opportunity.”