Cape Argus - Scientists weigh up tomorrow�s �greener� fuels

In a scramble to find alternative energy sources as global forces put pressure on the world’s oil reserves, scientists and experts have discovered a range of possible fuels.The most widely available “green” alternative to petrol is Liquified Petroleum Gas, or LPG. Although a fossil fuel, it is a byproduct of petrol.Others include bioethanol and biodiesel, which are green fuels made from grain, rapeseed and vegetable oils.They produce 65% fewer greenhouse-gas emissions than petrol, because carbon emissions during production and consumption are almost equal to the amount removed when the crops from which they’re made are grown, says the UK government’s Central Science Laboratory.And if those don’t satisfy, there is also organic matter, which generates methane when it rots. When released into the air, methane traps 20 times more heat than carbon dioxide, but when burnt, it releases up to 25% less carbon dioxide than the combustion of the same mass of coal. Scientists are now exploring ways of converting methane into fuel.“Converting organic waste into fuel is an elegant and sustainable solution,” says alternative fuels consultant Jo Burge. “However, biogas is a local fuel – it’s most efficient to use close to where it has been generated, as moving it around the country is costly and may, in turn, damage the environment.”Hybrid cars have become must-have modes of transport in the US, with celebrities such as Salma Hayek and Leonardo DiCaprio choosing them above petrol-only cars.The hybrids are powered by a combination of electricity and petrol. Car-makers claim they are greener than standard vehicles because an integrated electric motor helps the engine by boosting it during acceleration, improving fuel economy. The electric motor also runs the car when stationary to minimise emissions, and the battery charges itself up with energy recovered during deceleration.
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“Essentially, hybrids are a fuel-saving device,” Burge claims. “They can be pleasant to drive – quiet and smooth – but they’re still basically driven on petrol and struggle to better the efficiency of the latest diesel models.”Typically, as much of the energy released when petrol is burnt is lost through a car’s exhaust system as heat. BMW promises its Turbosteamer will cut the amount of energy lost by 80%, by ensuring energy from exhaust gases is used to power a steam engine which powers the car.“The BMW system is a clever way of recovering energy that would otherwise be lost. But this is still a petrol-driven car,” he adds.Car-makers have been experimenting with solar power for years. In 1993 the Honda Dream won the World Solar Challenge, crossing from Darwin to Adelaide in Australia using only the power of the sun.Today, manufacturers are continuing to look at ways of incorporating solar panels into car design.Around 1 400 UK petrol stations now sell LPG and E85 – a mix of 85% bioethanol and 15% petrol. In a pilot scheme seven independent UK petrol stations now sell B5 biodiesel produced from rapeseed or vegetable oil.Ordinary cars can run on a mix of 95% petrol and 5% bio-ethanol or biodiesel, without any modifications. However, to move beyond 5%, an engine must be modified.It is more expensive than petrol because of the cost of producing and distributing it. Another concern is whether there is enough grain, rapeseed and vegetable oil to produce the necessary volumes of bioethanol and biodiesel.Fully electric cars cost almost twice as much s standard vehicles. And although they produce no emissions, they’re only as green as the electricity used to power them, says John Roberts, director of the consultancy Arup Energy.