Welsh Company Riversimple Unveils RASA Hydrogen Fuel Cell Car That Does 300 MIles On 1.5 Kg of H2

At the moment, electric cars and plug-in hybrids are in an ongoing battle with hydrogen fuel cell cars to become the defacto fuel choice of the future.

For now, thanks to companies like Tesla Motors and Nissan, electric cars have the edge when it comes to market penetration. With falling lithium-ion battery prices, increasing energy density (and thus increased range), a rapidly-expanding public rapid charging network and falling sticker prices, electric cars win over hydrogen fuel cell vehicles when it comes to price, service costs, practicality and refueling availability.

If we’re honest, the only real advantage production hydrogen fuel cell cars like the 2016 Toyota Mirai hydrogen fuel cell sedan and 2016 Hyundai Tucson hydrogen fuel cell SUV have over electric cars is the speed at which they can be refuelled. When you take into consideration the overall inefficiencies of a hydrogen fuel cell vehicle compared to an electric car however, that advantage isn’t enough alone to make hydrogen vehicles a sensible choice for the future.

Electric cars have the edge on most hydrogen cars today.

Electric cars have the edge on most hydrogen cars today.

But what if you could improve the energy efficiency of a hydrogen fuel cell car? What if, instead of travelling 300 miles on five kilograms of hydrogen, it could do the same distance on just 1.5 kilograms? Would that make up for the shortfalls of hydrogen fuel cell technology?

Riversimple, a small automotive engineering company from Llandrindod Wells, Wales, thinks so. And to prove it, the company has just unveiled the Rasa, a road-legal hydrogen fuel cell vehicle that seats two and can travel a claimed 300 miles on 1.5 kilograms of hydrogen. Unlike the 2016 Toyota Mirai hydrogen fuel cell sedan, 2016 Hyundai Tucson FCV and soon-to-launch 2017 Honda Clarity fuel cell sedan however, the Riversimple Rasa isn’t a hydrogen fuel cell vehicle built to appeal to existing automotive trends: it’s built to maximize energy efficiency.

The Riversimple Resa is designed for a low coefficient of drag.

The Riversimple Resa is designed for a low coefficient of drag.

From a distance, there’s a striking similarity to the first-generation Honda Insight which recently joined the Transport Evolved staff car fleet.Small and sleek, the Riversimple Rasa is a two-seat coupe with sweeping roof line that leads to a narrow kammback rear, with the rear wheels enclosed behind aerodynamic rear quarter panels. Then there’s the butterfly doors which hinge upwards and outwards from the vehicle’s roof, making the tiny electric car appear almost double its size when its doors open.

While Riversimple hasn’t given an official coefficient of drag, the sleek design of the Rasa has been constructed to minimize drag as much as possible, ensuring the tiny car uses as little energy as possible to move itself along. Combined with a carbon-fiber composite chassis weighing just 40 kilograms (88 pounds) and similarly light body panels the tiny car tips the scales at 580 kilograms (1279 pounds). That, says Riversimple is about half the weight of a traditionally-built small car. For comparison however, we note that the new 2017 Smart ForTwo two-seat microcar weighs in at about 1984 pounds — which is 705 pounds heavier than the tiny fuel cell coupe.

By contrast, the 2016 Toyota Mirai hydrogen fuel cell sedan, while it can seat four adults, is more than 4,078 pounds.

Aerodynamic design and lightweight construction isn’t the only thing which makes the Resa stand out against other hydrogen fuel cell cars. Instead of a large, hard-to-cool hydrogen fuel cell stack, the tiny car has an equally tiny fuel cell stack rated at 8.5 kilowatts. That’s less than one tenth of the hydrogen fuel cell stack in the Mirai, yet still manages to power the Resa to a top speed of just over 60 mph. We’ll admit that top speed is far too low for serial production, but for now, this vehicle is an exercise in frugality, not speed records. The tiny size means that it’s also far easier to cool the fuel cell stack than other hydrogen fuel cell cars we’ve seen, minimizing the amount of cooling system components needed to keep it happy.

Inside, there's seating for two and not much else.

Inside, there’s seating for two and not much else.

Converting that power to motion is a quartet of in-wheel electric motors which drive thin, low-rolling resistance tires. While the hydrogen fuel cell tank and fuel cell stack live behind the passenger compartment in the rear of the vehicle, the underhood area houses a small bank of supercapacitors specifically designed to help recapture energy during regenerative braking and then feed that power back to the wheels during heavy acceleration.

Riversimple says the Resa manages a fuel economy of around 250 mpge according to its own calculations, and emits 40 grams of CO² per kilometer driven using a well-to-wheel life cycle analysis assuming the is powered from hydrogen reformed from compressed natural gas.

Sadly, there are no other specifications to share, nor a projected price. Riversimple tells Transport Evolved however that the vehicle has been designed by a team of engineers whose previous titles have included positions at Formula 1 race teams and aerospace engineering companies. Moreover it promises, the car has been built to pass all necessary crash-testing in the European Union, features just 18 moving parts, and is being developed using an open-source methodology to encourage others to build on its technology and further development of lightweight, energy-efficient vehicles. To date, it has been has been awarded more than £4 million of total funding from a variety of sources, including the European Union and the Welsh Assembly, to continue developing and refining the Resa.

Yes, it's frugal. But is this the type of car we should all be driving?

Yes, it’s frugal. But is this the type of car we should all be driving?

The next stage of the project is a 12-month trial of 20 prototype Rasa hydrogen fuel cell cars in the UK, where the cars will be offered to individuals on a case-by-case basis, dependent on their proximity to fuelling infrastructure and suitability for the project. After that, Riversimple promises production vehicles will hit the market in 2018.

If we’re honest, we can’t see cars like the Riversimple Resa reaching mass-market appeal. Why? The small size, limited top-speed and funky design won’t bode well with the average car buyer, especially in car-mad countries like the U.S.

But as a reminder that cars don’t all have to be large, gaz-guzzling and excessive in every way? We think it’s an excellent wake up call.


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  • Ad van der Meer

    Don’t mind that I will wait to get into this car until crash tests have been performed and have concluded this car is safe. I think we all saw what happens is a Smart ForTwo bounces off a Mercedes Benz S-Class. I don’t want to be the crash test dummy to try that same crash in this car.
    I wonder what the fuel efficiency of this car would be if an internal combustion engine would power it.

    As to CO2 emissions… 1.5 kg H2 to drive 300 miles
    For every kg H2 produced, about 28 kg of CO2 is produced with Steam Methane Reforming. 28831.41 * 1.5 / 300 / 1.609 = 67.8 gr CO2 per km driven. This calculation does not include CO2 produced in the production of the steam needed for this process.

    • Matt Beard

      I would be willing to bet a large amount that this vehicle will be “safety tested” as a heavy quadricycle and as it is intended to be a low volume product it will be approved via Small Series Type Approval which I believe don’t actually require actual crash testing. This is probably just as well as the layout on the manufacturer’s website shows a stainless steel hydrogen tank placed at the rear of the vehicle worryingly close to the rear bumper.

      • bill

        Note: its a composite fuel tank and there is a boot behind the tank. It will be fully crash tested and have whole vehicle type approval. The vehicle at the moment had has specialist crash simulation applied and has outperformed expectation.

        • Matt Beard

          Ah… I would be very interested to know the source of this information.

          I took the tank construction to be stainless steel as it has been stated that it is from Swagelok – A company that specialises in stainless steel hydrogen tanks. A simple supplier breakdown is here: http://livedoor.blogimg.jp/motersound/imgs/b/0/b09ed7bc.jpg

          The location of the H2 tank I got from this image on the Riversimple website: http://riversimple.com/wp-content/uploads/2015/10/car-2.png

          • bill

            Hi Matt. The tank is made by quantum. All of the pipework and fittings are swagelok . The image they post is a bit misleading as the flat panel you can see at the back forms the front of the boot section. Hope that helps Matt. Regards Bill

          • Matt Beard

            You seem to know a lot about this car, it’s production and composition. Is there a good reason for this?

          • bill

            Matt. I have no secrets. I work at Riversimple and built the hydrogen system myself. Wasn’t trying to be clever . Just wanted to educate and avoid speculation. I genuinely believe they we are doing great things with a long term view of a zero carbon transport system. Regards Bill p.s. most welcome to answer any questions (to the best of my ability) you or others may have.

          • Bill — let’s talk. Reach out to us via the Contact Us page (https://transportevolved.com/contact-us/) and we’d like to arrange to have a proper chat. Are you able and willing to set up an interview?

  • MikeM

    “At the moment, electric cars and plug-in hybrids are in an ongoing battle with hydrogen fuel cell cars to become the de facto fuel choice of the future”.

    This ongoing battle reminds me of the battle with my 1 year old grandson when he would feebly beat on my knee with his tiny fist.
    In other words – either it was hard to notice there was an actual battle going on, or the battle was already over before it began!

    Does anyone take this kind of off-the-wall hype seriously?

    • Chris Stanley

      My thoughts exactly. Where’s the battle? Many thousands of BEVs are sold every year and that figure is rising exponentially whereas hydrogen vehicles are… well, nowhere! When the battle finally does start they’re going to have a hell of a mountain to climb.

    • bill

      there is enough Lithium on the world to exchange 1/3 of the worlds ICE engines to battery power – if we are to transfer to a zero carbon transport system, how do you propose we power the other 2/3.
      Battery Electric Vehicles are currently winning because the tech is simpler but it is not the total answer and the long term will have to feature both technologies.

      • An EV Driver

        Please let us know: (1) what the effect on range is when you start the heater or AC, and (2) what the current hydrogen network looks like or will look like to support the Riversimple car, including re-fill costs and daily availability.


        • bill

          Hi. The UK car will not feature aircon. It will have a heater but I don’t have calculations to hand. ( sat in my garden enjoying the rarely sighted sun, in this part of Wales!) What I can tell you is that it will have less effect on range than battery cars as we will be scavenging some waste heat from the fuel cell. Something not possible on a BEV of course.
          Riversimple have designed a car around a business plan. It is a local car with 300 miles range or a weekly fill if you look at it a little different. We will install a small refueling station (we don’t need a large one as our tanks contain only 1.5kg of h2. We then expect to offer our sale of service model in a 20 to 25 mile radius of that filling station. This will allow us to build a network incrementally and then follow with a 4 seater motorway capable model in the future.
          Costs of fuel are irrelevant to our customers as the company will pay. This will drive the company to search for greater vehicle efficiency in the future. Please take a look at the riversimple website for more details. Hope that helps.

  • Chris O

    Curious they didn’t make it an EV rather than a HFCV. Needing only a relatively small traction battery It might have carved out a niche for itself as a cheap to run urban runabout with real environmental benefits. Fitted with expensive HFCV technology it’s a complete non starter as nobody will pay a premium for a compromise.

    • bill

      Hi Chris. The idea of a battery was examined but dismissed. People make a common misconception that h2 is inefficient. This is true if you look at powertrain efficiency on its own. A more accurate way is to examine whole vehicle efficiency. The Rasa manages approx 10.9 kW per 100km. By comparison the Nissan leaf is approx 21kW per 100km. Weight is key. I hope to be publishing a more accurate explanation of this in the next week.

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