The next-generation Hyundai ix35 is due in 2015, but the company is pressing ahead with a hydrogen version of the existing car. We got behind the wheel of a pre-production model to investigate the powertrain.
Unlike cars that burn liquid hydrogen as an alternative to petrol through a conventional engine, the ix35 Fuel Cell converts hydrogen to electricity that is used to power an electric motor.
There's also a battery pack that stores energy harvested from regenerative braking; this can also be used to power the electric motor. The only tailpipe emission is pure water.
Hyundai says the key advantage hydrogen fuel cell cars have over pure electric rivals is that you don't need to change your lifestyle to own one. Whereas a plug-in electric car typically takes several hours to recharge, the ix35 Fuel Cell can be refuelled in a couple of minutes.
What's the Hyundai ix35 Fuel Cell like to drive?
The ix35 Fuel Cell has three driving modes one that uses only the fuel cell to power an 87bhp electric motor, a second that boosts performance by sourcing extra power from the battery pack, and a third that diverts some of the fuel cell's power to recharge the battery.
Performance is almost on par with the 1.7-litre diesel version of the ix35; 0-62mph takes 12.5 seconds and top speed is 100mph.
Because the hydrogen is delivered to and stored in the car as a gas, the Fuel Cell doesn't return a conventional mpg figure. The tanks have a capacity of 5.6kg of hydrogen, which gives a range of about 400 miles. That means 1kg of hydrogen will take you 70 miles.
Like other electric cars, the ix35 Fuel Cell produces its maximum torque (221lb ft) from standstill, so power delivery, even at low speeds, is responsive and smooth.
The car weighs considerably more than a conventional ix35 about two tonnes with a driver on board.
Despite its substantial bulk, though, the car feels responsive enough around town. The extra weight actually gives a modest improvement in ride quality over petrol- and diesel-powered ix35s, too.
Urban refinement is impressive, because like most electric cars the Fuel cell is virtually silent. We didn't get to test the car above 30mph, but the standard ix35 does suffer from wind- and road noise at higher speeds.
The steering is initially light off the centre, but heavier than you'd expect at low speeds. However, the ix35 never feels unwieldy or difficult to manoeuvre.
Regenerative braking performance on some electric cars can be overly sensitive, but the ix35's system seems to avoid this frustration with a much more conventional initial bite followed by adequate stopping power.
What's the Hyundai ix35 Fuel Cell like inside?
In this respect, the ix35 Fuel Cell is near-identical to its conventionally powered siblings, which means you get the same practical and smartly styled cabin.
The only noticeable changes are the reconfigured instruments; instead of a rev counter, you get a dial showing current power use and energy recuperation. There's also a colour screen that gives more detailed information.
Driver and passenger space is identical to the standard ix35, with the only practical capacity difference being a reduction of around 150 litres of boot space (down to 436 litres) to accommodate the hydrogen gas tank.
Should I buy one?
You can't, for now. The first batch will be leased to private and public fleets, with the aim of demonstrating hydrogen fuel cell technology to a wider audience.
The company plans an initial run of 1000 cars between now until 2015, at which point the next-generation ix35 will be launched and Hyundai hopes to be making around 10,000 fuel cell models every year.
The two biggest issues with owning a hydrogen car at the moment are the price and the number of filling stations in the UK.
There are currently just twelve places to refuel, and while this number is expected to increase to 65 by 2015, that's still a tiny amount compared with the amount of petrol stations.
The cost of the Fuel Cell hasn't been announced, but it's likely to be significantly more than the conventional ix35.
The ix35 Fuel Cell isn't pitched as an alternative to petrol- and diesel-powered crossover rivals, mostly because it will be too expensive and at the moment impossible or inconvenient to refuel for most buyers.
However, as a technology showcase it certainly impresses. For early adopters with easy access to existing or planned hydrogen fuelling stations, it could be a tempting proposition.