Green Piece

Date: Wednesday, April 28, 2010

All fuels have to be treated with respect, but it’s mythbusting time. Thanks to the Hindenburg disaster the general perception of hydrogen is that it’s highly combustible and lethal. The real problem on the air ship was the hydrogen peroxide paint (basically solid rocket fuel), not the hydrogen providing the lift.

Hydrogen burns at a significantly lower temperature than petrol and is 22 times weaker than petrol vapour in theoretical explosive power per unit volume of gas. It is also 12 times more diffusive than petrol and accumulates as high as possible rather than low to the ground as a potential ‘fire carpet’ as petrol does.

Nevertheless the tanks have to pass a stringent regime of test, as do all hydrogen tanks. An armour-piercing bullet ruptures the tank, but there’s no explosion, for example.

H2 Production

As hydrogen doesn’t occur naturally — released in the wild it combines with oxygen to form water — it has to be produced and the easiest and ‘greenest’ way is by using an electrolyser (ITM Power is a specialist in this area) combined with a compressor. Electricity passed through water produces hydrogen and oxygen. Plug it in and hydrogen is produced, stored and can then be quickly transferred to the vehicle tanks.

With a conversion efficiency rate of 80 per cent it takes about 10 litres of water to produce enough hydrogen to fill the three tanks.

As with many of the proposed ‘green’ fuel solutions it’s the lack of any re-fuelling infrastructure in the country that is holding up their uptake. To make the most of it, and in this case minimise the use of petrol instead of hydrogen, the operation must be return-to-base to make sense.

On the Road

Turn the key with the fuel switch set to H2 and the Transit comes to life and it’s a bit of a shock initially. Thanks to the 2.3-litre petrol lump under the bonnet there is very little noise; something we’re not used to. Whenis the last time you drove a petrol-engined van?

The shock continues as we pull away; there’s an almost complete lack of torque. Having re-programmed the brain things settle down, but there is a noticeable lack of power. In fact running on hydrogen drops the power output from 150hp in petrol mode to 90hp. It takes approximately twice as long to reach 60mph.

Progress is sedate and peaceful, and everything is running smoothly. And, of course, there’s very little coming out of the exhaust pipe apart from water vapour and a bit of NOx. Revolve admits that there is a bit more work to do to fine-tune the system with regard to NOx output. It’s very low at high throttle loads, but a bit too high under a quarter throttle. This will be remedied shortly.

Driving the H2ICE Transit means that you can look down on Toyota Prius owners with disdain; and it’s a good feeling.

Revolve reckons in urban usage H2 fuel economy runs at about 31g/km which will provide a range of about 133km (83 miles). Take it out on the motorway and it increases to 25g/km which equates to 193km (120 miles).

Technically, hydrogen-powered vehicles cannot be licensed for UK roads, but this is something that Revolve is working on with the powers that be. The Royal Mail is currently trialling two H2ICE Transits in Stornoway on the Isle of Lewis in the Outer Hebrides.

Verdict

This technology is very much in its infancy so is not cheap at about £45,000, but the fact that it is a bolt-on conversion is a real plus-point. There’s definitely more work to be done, but the price will drop as economies of scale kick-in. A piece of British technology to keep an eye on.