Honda Clarity review: We drive the world’s most advanced hydrogen car

The race for a sustainable transport solution is on, and while electric vehicles are by far the most popular choice right now, the truth is there’s another option out there: hydrogen power. Yes, the same element they use as rocket fuel is being used in cars, and although it sounds like a catastrophic idea, it actually makes sense, and comes with a lot of benefits.

Honda Clarity review: We drive the world's most advanced hydrogen car
By Curtis Moldrich

Car manufacturers think so too, and they’re throwing R&D money at it by the billions. Honda has run with the idea of hydrogen cars for the past 30 years or so, and in recent decades Toyota, BMW, Hyundai and Audi have followed suit too. Even Jeremy Clarkson likes them.

Following 30 years of development, Honda is now committed to bringing Hydrogen power to our roads, and that’s why I travelled to Denmark to drive the Honda Clarity FCV – the most advanced hydrogen fuel-cell car in the world.



I’ve already driven two hydrogen cars, the Toyota Mirai and the Hyundai ix35, and the Honda Clarity easily looks better than both. With a similar insect-like, incisive front-end to the much faster, conventional Honda Civic and the NSX supercar, the Clarity looks futuristic, aggressive and cutting-edge. You can find more pictures of it here.

It’s very different to those other cars, though, and the biggest difference – besides the huge tanks of hydrogen (which I’ll get to later) – is the size. This car is massive. It’s larger than the previous Clarity, and with swooping bodywork and ample room to seat five adults, it’s yacht-like.honda_clarity_review_10

Take a closer look at the vast expanse of white, pearlescent body work, however, and you’ll discover some nice attention to detail. The rear wheels are covered for maximum efficiency, and around the car you’ll see a series of small slots, designed to channel air around the car with the least resistance.

The reason I went to Denmark, though, and why you’re reading this isn’t for the Clarity FCV’s looks; it’s to find out about the groundbreaking way it’s powered. The Honda Clarity is a fuel-cell vehicle, and that means it generates power using hydrogen. So, how does it work? Time for a chemistry lesson.

How does the Honda Clarity work?

Like the Toyota Mirai, the Clarity splits H2 hydrogen molecules using a proton exchange membrane into two hydrogen atoms. Electricity and H1 molecules are produced as a byproduct of the reaction, and it’s the juice from this chemical reaction that powers the Clarity’s motor.

Since hydrogen can’t produce electricity on-demand fast enough for normal driving, a small battery sits between the hydrogen stage and the motor, acting like a temporary buffer. As for the waste? The free H1 waste products bond with oxygen in the air to make water vapour, the Clarity’s only byproduct.honda_clarity_review_1

You might be thinking, why not just burn the hydrogen like you combust fuel in a normal engine? The answer is efficiency. Simply put, conventional engines waste a huge amount of energy and are often around 20% efficient at best. By using hydrogen in this manner, however, Honda says the powertrain can run at around 60% efficiency.

Of course, that’s just a very basic explanation, and there’s far more going on in the Clarity. Just like hybrid cars and EVs such as the Nissan Leaf, the Clarity can also reclaim power when coasting or braking and this energy goes back into the buffer battery to run the engine.


Honda Clarity: At a glance

  • Range: 366 miles
  • Price: £41,000 where available
  • Weight: 4134lbs

Hydrogen risks

The hydrogen itself is stored in two pressurised tanks, which are positioned below the boot and also under the rear passenger seats, but as unnerving as that sounds, the Clarity is actually very safe.

The H2 tanks are lined with aluminum and wrapped with fibreglass, so they’re extremely resistant to damage and they’ve been tested both inside and outside the car, too. And sensors placed around the car will shut down the hydrogen tanks if a leak is detected.  

Hydrogen itself also isn’t as volatile as you think. It’s less dense than normal air, so will quickly disperse from the car if there’s a leak. What’s more, Honda engineers say the mixture of hydrogen and air will almost always be too lean or too rich to catch fire  – even with a naked flame present.1347_anp1307


My route around Copenhagen involved a refueling stop, but this wasn’t a huge oversight on Honda’s part. Instead, the refuelling stop was there to demonstrate one of the main advantages hydrogen power currently has over contemporary EVs; charging time. Unlike EVs which can take from 30 minutes to ten hours to charge, depending on the power outlet you use, hydrogen cars take a few minutes at most to refuel. If you can find somewhere to charge them, that is: At the time of writing, there are only six functional h=H2 stations in London, and a further seven across the rest of the UK, so it isn’t what you’d call mainstream.

Interior and infotainment

The Clarity is at the very cutting-edge of motoring technology, yet I rarely really felt I was sitting above a moving laboratory. Inside, the Honda feels roomy and solid, with basic yet svelte controls forming much of the interior. Interior surfaces were covered in a mixture of Alcantara, leather and high-quality plastic, and although it can’t compete with the BMW, Mercedes and Audis of this world, it’s by no means awful.

There are nice touches in the cabin, too. You select gears using robust, intuitive buttons, and there’s even a cubby hole just for your sunglasses – which actually proved useful in Denmark. But then there’s the infotainment system.

It’s snappy and generally feels responsive, which is positive, but the whole user interface looks as though it was made five years ago. The Clarity’s 8in, 800×480 WVGA touchscreen sits above the the dash, and it isn’t particularly bright. As soon as it encountered a bit of Danish sunlight, it became unreadable.img_1456

The satnav was fine for the most part, although on occasion it would give directions later than you’d like.

To change the volume in the Clarity you’re forced to use the large touch-sensitive buttons located to the left side of the screen. Touch-sensitive buttons are always temperamental, even in the Mercedes E class, so it wasn’t surprising to find them unreliable in the Clarity, too. On the plus side, the Honda supports both Apple CarPlay and Android Auto.

These minor issues are a shame, because driving the car is a composed, and stately experience. The Clarity isn’t a sports car – its size and weight tells you that – but it offers a convincingly comfortable ride. In a straight line, the Clarity picks up speed in a graceful manner, and the Clarity ate up miles with almost no road noise as I made my way around the centre of Copenhagen.

Interestingly, the Clarity has a Sport mode that makes acceleration snappier, and makes decceleration stronger when you take your foot off the accelerator. Honda says it’s supposed to mimic the feel of an engine braking, and it’s similar to what you’d feel when you put a Nissan Leaf into its more thrifty B mode.

This doesn’t make the Clarity a one pedal car – you do still need to use the brake to stop – but it does make driving that bit more engaging. It’s really a shame this Sporty deceleration isn’t present in both modes – hopefully, Honda will offer a patch in the future.honda_clarity_review_3

Price and Verdict

If you’re reading this, chances are you’re interested in hydrogen fuel-cell technology, and what it means for the future of cars and road transport in general – not because you think the Clarity could be your next car. And that’s fine for Honda, because there’s one major catch: the 2017 Honda Clarity isn’t going on general sale at all in the UK.

Instead, it will be run in small, leasing fleets in more popular markets, and sold in small numbers for a loss-making £40,000 in Japan and the US. Instead, Honda says that it will be the next-generation Clarity that will be the one the company chooses to sell worldwide.

So where does that leave the 2017 Clarity FCV? It isn’t for sale or leasing in the UK, so why build it, and why invite UK journalists to try it out? Simply put, it’s a showcase for hydrogen technology, and a very good one at that. It’s simple to refuel, easy and pleasant to drive, and delivers the sort of performance and range you’d expect from a conventional car (with a small fuel tank).

Of course, you have to take that with the usual caveats about hydrogen cars such as public opinion and infrastructure – but on its own merits, the Clarity presents a compelling argument for hydrogen power.

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