Electric cars like the Tesla and the Nissan Leaf have been the deserved focus of media attention recently, but hydrogen-power is still drawing huge investment from manufacturers.
How close are you to being able to buy a hydrogen powered vehicle? It's the holy grail of motoring, emitting only water and heat.
Hydrogen offers key advantages over electricity, with cars boasting more range and not requiring hours to recharge. A hydrogen fuel infrastructure could also look much like the existing petrol infrastructure, with pumps and nozzles meaning less of a headache for the general public.
There are two forms of hydrogen car. The first is the hydrogen-powered internal combustion engine, a tank of hydrogen powering the engine instead of petrol. BMW's Hydrogen 7 is the first production car of this type and 100 are currently out on loan, with BMW getting consumer feedback.
The second and perhaps ideal model is the hydrogen fuel cell, which does away with the combustion engine altogether. This vehicles use electric motors which combine hydrogen and oxygen in the fuel cell. This process produces the required electricity.
With this in mind, Honda has launched the FCX Clarity. This fuel cell car that can do 100mph, has a 0-60 time of 10secs and a range of around 240 miles. The car has been winning plaudits all over; yet such technology does not come cheap.
A single car reportedly costs Honda around $500,000. You are also unable to buy one, instead being able to lease the Clarity for three years at $600 a month - if Honda choose you. And it's best if you live in California where the majority of these vehicles reside. There's only Clarity in Britain at this time.
The costs involved in producing such a car will inevitably fall over time. There are however two bigger issues which need to be resolved before hydrogen-powered cars become an everyday reality.
The main one is producing the hydrogen in the first place. Hydrogen is the most abundant element in the universe but actually turning it into a fuel cell requires an immense commitment of power and resources.
Natural gas is the cheapest source of hydrogen but it is obviously not renewable, which some say defeats the whole point of using hydrogen in the first place. Some have also calculated that sourcing and extracting hydrogen is actually less fuel and cost efficient than simply using a petrol car.
Nuclear and solar power can however also be used to generate the hydrogen required. Honda has already developed a solar-powered hydrogen generator of a practical enough size to sit alongside your Clarity on your driveway.
Questions remain about infrastructure of course. California is slowly introducing stations across the state but a planned 250 refilling stations are slow in folling out in the current recession climate.
In Britain there are only a clutch of refuelling stations. The first of these was opened in Birmingham in 2008 but there are plans to turn the M4 into the UK's first hydrogen highway. Mayor of London Boris Johnson wants to introduce a network of hydrogen filling stations in the capital.
For now then, an electric or hybrid car is where the smart money is. But in ten years time, expect to see the hydrogen car finally begin to er enter its element.