Dunbarton Energy Committee
The most popular "green" vehicles today are the hybrids, such as the Toyota Prius, Ford Escape and Fusion Hybrids, Honda Civic Hybrid and the Nissan Altima Hybrid. The Environmental Protection Agency (EPA) has awarded 17 cars its "SmartWay Elite" designation in 2010 -- the greenest vehicles on the road -- and not surprisingly, most of the cars on the list are hybrids. The most energy efficient so far is the Prius, which is rated by the EPA at 51 Miles Per Gallon (mpg) in city driving (in large part because it simply shuts off while stopped).
Hybrids are powered by both gasoline and electricity. They capture the energy in braking and engine-braking (which would normally be dissipated as heat) and use it to recharge a battery which runs the vehicle's electric engine. This combination is the source of the hybrid's high gasoline mileage.
Many people are promoting Plug-In Hybrids (PHEVs). These have a standard hybrid design but are plugged in to recharge from an ordinary electrical outlet, typically overnight, so that the first 20-60 miles (depending on the design) are powered entirely by the electric motor. Thus the first 20-60 miles are free of tailpipe emissions* -- and many people rarely drive more than 20 or 30 miles per day.
Other designers are working toward all-electric vehicles. The Chevrolet Volt, which the company predicts will be available in 2010, still uses gasoline, but only to recharge the battery once it has reached the limit of its range. Nissan is advertising research projects which will result in vehicles driven entirely by electricity. Tesla claims that its all-electric car will run 244 miles on a single charge.
*However, note that "tailpipe emissions" are not the same thing as "air pollution" or "carbon footprint." The electricity to charge a car has to come from somewhere. Depending on where the charger taps into the electrical grid, a car recharged mainly by power plants burning coal (for example) could have a greater carbon footprint than a car powered only by gasoline.