SciencePhiles
Electric Hot Rod
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Duncan Ende's next ride?
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Friends, Duncan Ende and the "KnowledgeNews racing team" have wrapped up their 2007 road-racing season. With three top-10 finishes on the year (including two in the top 5), Duncan and the team did pretty well for being the new kids on the (engine) block.
Next year? Well, maybe next year Duncan will trade in his Porsche 997 for the quicker Tesla Motors Roadster shown above. About to be rolled out by a Silicon Valley start-up, the Tesla Roadster can go from 0 to 60 miles per hour (100 km/h) in less than four seconds. The real surprise: it's an electric car. Is this the future of racing? Is this the future of driving? Let's plug in our brains and see.
Positive Charges
Electric cars are nothing new. They've been buzzing around for as long as gas-burners have. In fact, a century ago-- before Henry Ford's Model T--a good share of the cars, trucks, and buses hitting U.S. city streets were electric. Heavyweights like Thomas Alva Edison even bet a decade of work on batteries that they would be the future.
Henry Ford has obviously gotten the better of that bet so far. But Edison was no fool. From a mechanical perspective, electric cars are generally simpler and more durable than gas-burners, with fewer parts to manufacture and maintain. The motor in the Tesla Roadster, for example, has only one moving part--the rotor--and weighs just 70 pounds (32 kg).
Electric cars also make far less mess per mile. That's true even if the electricity they need to magnetically turn their motors ultimately comes from a coal-burning power plant. (And in the United States, about half the nation's electricity still comes from burning coal. Just see the U.S. sources of electricity chart below.)
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Source: U.S. Energy Information Administration, 2005
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How can burning coal for Edison be less polluting than burning gas for Ford? For one thing, pollution is easier to control if it comes from a single plant rather than a million tailpipes. (Electric cars don't even have tailpipes.) For another, electric motors are more efficient at converting energy into mileage. Gas-burning engines typically turn only about 20 percent of input energy into mechanical work. The rest is lost as heat. The Tesla Roadster's motor converts more than 80 percent.
Negative Charges
So why did Edison lose his bet on the electric car? At least in part because he failed to make a significantly better battery. Some of the earliest electric cars, built in the 1890s and 1900s, could go 50 to 80 miles (80 to 130 km) on a single lead-acid battery charge. A century later, many electric cars still can't go much farther than that.
Lead-acid batteries--good old car batteries--just don't have the juice. But now, cell phones, laptops, and digital cameras are driving the change that may change driving. In particular, they're driving the development of nickel-metal hydride (NiMH) and lithium-ion (Li-ion) batteries--batteries that can hold more charge in less space than ever before.
The engineers at Tesla Motors, for example, are powering their roadster with what they say is "one of the largest and most technically advanced Li-ion battery packs in the world," to give it a range greater than any electric car in history: 245 miles (400 km). It's basically a 1,000-pound (450-kg) laptop battery. Whether electric cars can ever overtake gas-burners may depend on how good such batteries can get.
--Michael Himick and Steve Sampson
Search & Seize
How America Got Its Wheels
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