In less than 10 years, many of us will be driving a fuel cell vehicle (FCV), which relies on a totally different technology to the oil-burning cars we drive today. The FCV uses a relatively cheap, abundant and clean energy source - hydrogen - and emits no pollutants.
Hybrid cars - those powered by a small petrol engine and an electric motor, such as the Toyota Prius and Honda Civic Hybrid - are really only a fuel-saving stop-gap, even though some of the technology seen in hybrids will transfer to fuel cell cars.
The principle of FCV technology is not rocket science - despite being used for the first time by the NASA space program in the 1960s. To say an FCV is an electric car is correct, but that's only half the story. An FCV is fitted with a pressurised storage tank for the hydrogen, which is its "fuel" (and like a petrol car, you need to replenish the tank, at yet-to-be-built hydrogen stations). The hydrogen is drawn from the tank into the fuel cell and when mixed with oxygen has an electro-chemical reaction, producing electricity. It's a bit like a lead-acid car battery, except that the fuel cell will keep pumping out electricity as long as it's "charged" with hydrogen. Surplus electricity is stored in a super efficient lithium battery, providing extra electricity for the engine and for equipment such as lighting and air-conditioning.
The beauty of the fuel cell is that it uses a readily available chemical - hydrogen - and it's clean. When hydrogen is mixed with oxygen in the fuel cell to produce electricity, the only byproduct is water vapour.
The latest fuel cell prototypes have all sorts of ways of gathering and saving energy. The electric motors are regenerative - when they are not powering the car, for example when rolling to a stop or downhill, the motor acts like a generator (similar technology is used in hybrid cars like the Toyota Prius, where the brakes are regenerative - charge the battery when you brake).
There is much going on to improve the humble electric motor, too. Nissan's X-Trail FCV has two electric motors sandwiched together. The Super Motor, as Nissan calls it, has a new way of applying compound current to the electromagnets and has two rotors positioned both on the inside and outside of one stator, allowing power to be output through two shafts. Nissan says this motor design is more compact and efficient than if two motors were used and permits separate drive to left or right wheels.
One of the FCV prototypes closest to production comes from one of the world's most engineering-focused car makers, Mercedes-Benz, which showed its F600 Hygenius FCV concept at the Tokyo motor show last month. This car has been designed from the ground up as a fully operational fuel-cell vehicle. Many FCVs developed to prototype stage have been fitted to either existing body shells or been concept cars that will never be built. The F600 is the closest to real-world, production-ready as car-makers have got. It runs an 85kW motor powered by a fuel cell that provides a range of 400km.
Mercedes-Benz says that the F600's fuel cell is 40 per cent smaller than its engineers have been able to produce before, and that the fuel cell operates more efficiently. Mercedes-Benz engineers have redesigned the fuel storage, added an electric turbocharger and a new humidification and dehumidification system to improve the chemical process in the fuel cell.
The automotive world is about to see a technology revolution, and it will be led by the fuel cell.