What will speed mean in the future?

There are a lot of groups looking at how to combine low or no emissions with real speed. While speed remains a constant -- 100 miles per hour in 2008 is the same as 100 miles per hour will be in 2108 -- it looks like the source of that power will turn from petroleum products to electricity in the near future. Already, two competing electrical technologies, batteries and hydrogen, have shown they've got what it takes to produce high speeds.

A California company called AC Propulsion set the bar for all-electric sports cars when it created the tzero in 1996. What's remarkable about the tzero is that not only is it all-electric, it's also very fast and efficient. And while the tzero never actually made it into production, some of AC Propulsion's technology found new life aboard other all-electric sports cars, such as the Tesla Roadster.

Only three tzeros were ever built, but the extant models are capable of achieving acceleration from zero to 60 miles per hour in as little as 3.6 seconds [source: AC Propulsion]. That's only half a second behind the gasoline-powered 2008 Ferrari 430 Scuderia [source: Motor Trend]. The tzero also pushed the limits of all-electric cars' driving range. Consumers' fears of being stranded roadside in their electric cars without an electric outlet to plug into -- or simply being limited by the distances they could driver -- were put to rest by the tzero's proven range of up to 300 miles between charges. This range was provided by the car's battery pack, which consists of 6,800 lithium-ion cells [source: AC Propulsion].

The biggest drawback of electric cars is simply that they need to be charged eventually, and the process can take a few hours to complete. This is one clear advantage conventional cars have over electric -- "recharging" means pulling into any gas station and adding gas or diesel to the car, typically a five minute procedure.

A team from Ohio State University countered the challenge of recharging when it created the Buckeye Bullet (BB1), a battery powered, all-electric vehicle that set a land-speed record of 321 mph at Bonneville in 2004 [source: OSU]. To produce this kind of speed, however, all 400 of the nickel metal halide batteries were drained in a matter of 90 seconds [source: FutureCar: Discovery Channel]. So the BB1 was retired and the Buckeye Bullet 2 (BB2) was put into production.

The second incarnation of the high-speed racer doesn't get its juice from electricity stored in batteries. Instead, the electricity needed to power the BB2 is produced onboard from condensed hydrogen. The car's fuel cell combines oxygen and hydrogen, which produces a direct electrical current. The motor controller converts this direct current to an alternating current to power the motor. Like its predecessor, the BB1, the BB2 has plenty of power: a 700-horsepower engine [source: OSU]. But unlike the BB1, the BB2 doesn't require recharging.

The jury's still out on exactly what will produce the electricity that powers the sports cars of the future. But with hydrogen fueling stations appearing in cities like London, it looks like hydrogen could supplant batteries as a viable power source. And with an all-electric vehicle clearly capable of producing the speeds necessary for sports car application, who knows what new combinations of alternative power engineers might devise.

For more information on alternative fuels and other related topics, visit the next page.