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Race for a green car

April 2, 2007 By John Whitfield This article courtesy of Nature News.

Multi-million-dollar X Prize set for automotive innovation.

Start your engines: the X Prize Foundation has announced a competition to build an environmentally friendly car.

The winning vehicle will have to achieve at least 43 kilometres per litre (100 miles per US gallon), regardless of the type of fuel it uses. Its carbon emissions must be no more than 125 grams of carbon per kilometre. And it has to be cheap enough to expect sales of 10,000 each year. "We're aiming at the middle of the market," says Mark Goodstein, executive director of the Automotive X Prize.

On mileage, that will be a big leap up from today's US average of about 9 kilometres per litre. But it's not such a stretch on the carbon emissions front: today's European cars average at 163 grams per kilometre, and the European Union is already shooting for a target of 130 grams per kilometre across all cars by 2012. The greenest cars in today's mainstream market achieve something like 28 kilometres per litre and 100-120 grams of carbon per kilometre (see 'A clean race').

The competition aims to prompt the car industry to take some chances, says Goodstein. "There's extraordinary innovation, but not a way for those technologies to make it to the market. It's terribly risk averse."

Goodstein believes that the prize's challenges lie more in manufacturing and economics than in developing radical new technologies.

"To achieve 100 miles per gallon can be done with existing technology," agrees Rob Thring, an automotive engineer at Loughborough University, UK. "But it requires a fairly radical design."

The rules are so far in draft form, and are open to public comment for 60 days from 2 April. The prize's value has not yet been announced, but will "likely be in excess of $10 million", says the document.

The previous two X Prizes, for spaceflight and genomics, each had a value of $10 million.

Race you for it

The prize has two categories. Entrants in the 'mainstream' category must be able to carry four passengers, have a top speed of at least 160 kilometres per hour, do 0-95 kilometres per hour in less than 12 seconds, and have a range of at least 320 kilometres. They must also have air conditioning and a stereo.

The 'alternative' category must carry at least two passengers, have a top speed of at least 130 kilometres per hour, and a range of 160 kilometres. This category doesn't mention frills, although all vehicles must have windscreen wipers, lights, seat belts and so on.

The prize will culminate in 2009, in a series of races between the contenders over a range of different driving conditions, from long road trips to commuting in congested cities.

"The winner will be the car with the lowest overall time, but contestants must meet stringent goals on efficiency and emissions," says Goodstein. "If you burn rubber, you'll lose."

Go light

In the United States, the distance drivable on a given amount of fuel has actually gone down in recent decades: from 9.4 kilometres per litre in 1988 to 8.8 today. "But it's not the fault of car manufacturers," says Thring. "Customers are demanding more luxuries and goodies on their cars, and they all add weight."

Making cars lighter is the obvious way to make them more fuel-efficient, says Thring.

Thring believes the future ultimately belongs to cars powered by hydrogen fuel cells. The X Prize is open to considering hydrogen-powered cars, but only if the entrant can prove that there's an economically viable way of refuelling them. Electric cars, or hybrid electric-fuel vehicles, are definitely allowed in the running.


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