Audi A7 goes fuel cell

What is this?

An Audi plug-in hybrid that shuns the traditional petrol and diesel engine options to pair a hydrogen fuel cell with its electric drive. It's the A7 Sportback h-tron quattro.

What's so good about it?

It does 500km on a tank of hydrogen, emits absolutely nothing from the exhaust beyond water vapour and despite weighing nearly two tonnes, it can do 0-100km/h in 7.9 seconds. It achieves this by mating a front-mounted hydrogen fuel cell to two 85kW (rising to 114kW if the voltage is temporarily raised; think of it as a sort of eco-overboost) electric motors, one on each axle, and the same 8.8kWh lithium-ion battery as found in an Audi A3 e-tron.

This combination allows a peak output of 170kW (about 231hp), 540Nm of torque from zero rpm, proper quattro all-wheel drive and absolutely zero carbon emissions running. As it only chucks out water, the exhaust system is even made of plastic to save weight. The fuel cell, which operates in the voltage range of 230- to 260V, is supplemented by a turbocharger to force air into the individual cells, and it also has special cooling circuits; its energy efficiency is therefore 60 per cent, almost double that of a combustion engine. Audi says the cell has an operating temperature range of 80 degrees Celsius, with cold-starting performance guaranteed down to -28 degrees C.

Finally, the A7 Sportback h-tron quattro can cover 50km on its battery alone, with a full recharge via the on-board plug-in socket taking between two and four hours (the longer time is when using a domestic 230V power socket). The h-tron looks like any other A7 from the outside, it can get to 179km/h and it uses 1kg of hydrogen per 100km - roughly equivalent to 76.4mpg.

And finally...

If a proper hydrogen infrastructure develops to support it, and we have no doubt it will in the same way that electric charging points are springing up all across the world as EVs take off, then this could be the ultra-clean future of hybrid motoring.