By 2055, according to a recent report by Shell, the world's current deposits of oil will have run out. The car of the future will have to use alternative fuels: more efficient, longer-lasting and ideally emission-free. Not surprisingly, manufacturers are desperate to find a system and an energy source that will work, thus guaranteeing their own survival well into the 21st century.
Much of the groundwork has been done. Cars already exist that run on electricity, gas, methane, human waste, even coconut oil, but the technology has yet to be perfected in terms of efficiency. And although the internal combustion engine is only 20 per cent energy-efficient, even the most refined electric car achieves just half as much.
In the US, General Motors (with its ominously named Impact car) is working on the problem, while in France the Peugeot 106 Electric is already on sale (at pounds 8,500, without batteries); it will be on test in Britain with Coventry City Council next year. British Gas has a fleet of gas-powered vehicles, and in Australia and New Zealand taxis run on a dual system of petrol and gas.
There is, of course, nothing new about alternative fuels - particularly electricity. When the automobile was first conceived, electrical power seemed the obvious technology for it. As Thomas Edison remarked at the turn of the century: "People would never choose a smelly, noisy, unreliable and complicated gasoline car to a quiet, clean, reliable and simple electric one." Sadly, he was wrong.
When the first cars appeared in Europe in the late 19th century, many were powered by battery. Now, the quotient of electric cars in Britain is less than five per cent. But Edison and his ilk may yet have their day, for electricity is foremost among the three emission-free power sources favoured by manufacturers as they gaze into their crystal balls for the car of the future.
Electricity is not without its problems, though, and the storage of electrical power in batteries is the main one. As anyone using a laptop computer or camcorder will know, battery technology lags way behind that of the computer chip or autofocus camera. Car makers are finding the same problem.
"The biggest obstacle is range," says Rover's John May, responsible for perfecting the car technology of the future. "Many electric cars can only run for 70-100 miles on one charge." After that, drivers have to return home or to some suitable installation to recharge their batteries. At home, it is a case of just plugging into the mains, but there are still only a handful of public recharging stations (even in French cities like Brest and Le Havre, where the cars are most popular, they are rare).
Taking into consideration the generation of the electricity at a power station, the transmitting of the power to homes through the national grid, then into the battery, the efficiency of an electric car is down to 10 per cent - half that of a petrol engine.
New types of battery such as nickel-metal-hydride are more efficient than nickel-cadmium, but the real breakthrough may lie in hybrid systems. In America, Chrysler has married an electric motor to a gas turbine (similar to those used in aeroplanes) which charges up the battery as the car moves. At the flick of a switch, the turbine switches off and the car runs on electricity. The system is installed in Chrysler's Patriot racing car, which delivers an astonishing 500 horse power. Volvo is developing a car based on similar technology.
Though still strictly a fossil fuel, natural gas is an alternative that appeals to motor manufacturers. Gas reserves are predicted to last longer than oil, and gas has the benefit of working with existing engines. Stored under extreme pressure in a tank in the boot, the gas is injected into the engine just like petrol.
Virtually any flammable gas can be used in an engine like this. If consumer demand for it were there, the fuel could be as easily transported and distributed as petrol. Almost emission-free, gas has the added advantage of being less than half the price of unleaded petrol.
In New Zealand, gas-powered cars are not a thing of the future but an everyday reality. My taxi at Auckland airport on a recent trip could, at the flick of a switch, be powered by either petrol or natural gas. "You wouldn't even know we'd switched from one to the other," said driver John Anderson. "The engine is the same and the power is the same." Across the Tasman sea in Australia, most taxis and a large number of private cars and trucks run on hybrid gas and oil-based system. Many of the larger garages have natural gas and liquid gas pumps as well as those supplying diesel and petrol.
In the depths of New Zealand's rural South Island, far from the nearest gas station, farmers run methane-powered vehicles from the most natural of sources - dung. "Twelve of our vehicles ran on methane produced from chicken waste," says Bill Winmill, who until recently owned a large chicken farm near Dunedin. "It was half the price of petrol and fully tax-deductible. That's the way alternative fuels need to be pushed, to persuade more people to switch over." In Christchurch, the local council runs 90 vehicles on methane produced from human waste.
Here in Britain, there is more resistance to gas. Only 350 of the world's million gas-powered vehicles operate in the UK, mostly in a fleet of vans run by British Gas. But the incentives are there: it costs just pounds 2,500 to convert a petrol vehicle to gas, with a fuel saving of around 50 per cent over petrol or diesel; exhaust-pipe emissions are reduced by a massive 70 per cent.
At present, though, gas fuel is taxed at four times the rate of petrol. "There needs to be a clear tax advantage for natural gas to be made viable as a road fuel," says Tom Gorman, chairman of the Natural Gas Vehicle Association. "Right now, we have only 10 refuelling stations in the UK, all of them in haulage or bus depots."
But beyond the first decades of the 21st century, reserves of natural gas might also start to run short. "Hydrogen is one fuel many manufacturers are looking at," says Tom Gorman. "Nobody has actually built a car that can use it, but by 2010 or 2020 its use could well be widespread."
Rover, like most European manufacturers, is developing a hydrogen engine. "In the short term," says fluids and environment manager John May, "we are looking for a period of diversity, with many different types of fuels. In the longer term, the future lies with fuel cells that produce electrical energy from hydrogen and oxygen passing over a platinum catalyst."
Apollo spaceships used the design to power their on-board systems once in orbit. Now Ballard Power Systems, a Canadian company, has developed a fuel cell unit small enough and powerful enough to drive a car or bus. Once manufacturers are committed to hydrogen, it will apparently be as readily available and easy to use as petrol.
Perhaps the most progressive alternative fuel can be found in the South Pacific. When the oil runs out, and all alternatives have fallen flat, the inhabitants of Western Samoa and Vanuatu will have no worries. They can run their existing diesel engines on coconut oil.
"The oil from two coconuts will power a car or a truck for two kilo-metres," says Dr Dan Etherington, an agricultural economist at Australia's National University. "On most of the islands in the Pacific, there are enough coconuts to keep them going just about indefinitely." !