* Smart Electric Drive on trial * Fuel-cell put to the test, too * Our verdict here...
Mercedes-Benz's hydrogen-powered B-Class F-Cell has also been released to the public for trial and verdict.
The lucky few in Europe and the US who get to try out the B-Class F-Cell will pay about 800 (720) a month.
There's more than enough performance for the car to be happy on the motorway, as well as around town, and there's more than enough room for five people and their gear in the boot.
There are no exhaust emissions, it's near silent to drive and it returns the equivalent of 85.6mpg.
Mercedes predicts that hydrogen will eventually stabilise at nearly a third of the price of petrol or diesel 3 (2.70) a kilo, which is good for 60 miles so the F-Cell would be cheap to refuel and doesn't take eight hours of charging just three minutes at the pump.
However, this is where there's a problem those pumps.
Infrastructure, infrastructure, infrastructure
Even if you were to get your hands on one of the F-Cell cars, you wouldn't be able to fill it up in the UK. There are no public refuelling points and there's no strategy for establishing a small network, let alone one that's anything remotely akin to the 9000 sites we currently have for petrol and diesel.
There are a handful of sites in Germany, which, combined with the range of up to 250 miles, means the B-Class F-Cell is a realistic proposition there provided you plan your refuelling with military precision.
The only thing that comes out the back of a fuel-cell is water, right?
That's true, but the hydrogen has to come from somewhere. At the moment it's taken from compressed natural gas, so there's a CO2 impact there straight away.
Then there's the CO2 cost of the energy it takes to compress it, store it and transport it (currently via trucks running on diesel).
Overall, though, Mercedes reckons the well-to-wheel CO2 figure is still much lower than for an equivalent fossil-fuel powered car 196g/km for fossil fuels compared with 104g/km for hydrogen. It's not quite as low as the company's figure for electric cars at 87g/km, but it's not far off and there's not that eight hour recharge to schedule in.
There's also enough hydrogen waste product from industry to fuel 750,000 cars globally, according to Mercedes but you'd have to look at the CO2 produced by the processes involved in that, too.
Electric cars and fuel cells certainly have recharging and refuelling issues, but the Smart ED and B-Class F-Cell are exciting developments to be applauded and encouraged.
The more renewable energy is used to create the electricity or hydrogen, the cleaner they both become but even now they're greener than fossil fuels.
The more investment in technology and infrastructure there is, the better they'll become and that means more people will buy them and the technology will get cheaper as a result.
The question is, though, which comes first the chicken or the integrated refuelling infrastructure?