You never plug in these cars to recharge the battery -- you simply fill the gas tank.
The Toyota Prius, a five passenger hybrid about the size of a Corolla, gets 52 miles per gallon around town and 45 on the highway. The smaller Honda Insight gets 70 miles per gallon overall, making it the highest-mileage car ever to hit the mass market -- ideal for today's soaring energy prices.
Hybrid technology also works on a larger scale. In 1999, five hybrid busses ran up to 18 hours a day in New York City. The 40-foot busses used a diesel engine running at constant speed. The hefty batteries were used to accelerate and recover energy from braking.
Hybrids combine the best of electricity and gasoline. Instead of recharging through a plug, the batteries get their juice from a small, light gasoline or diesel engine. When you hit the brakes, kinetic energy is converted into electricity, and then stored in the battery. At a stop light, the engine shuts down entirely.
Hybrids sound good -- they are, for example, exempt from the range limitations of battery-powered cars. But even hybrids could seem passed by 2004, when major auto makers promise to start selling cars powered by fuel cells. Fuel cells make electricity without burning anything. They don't even have moving parts.
In the effort to cut auto pollution, hybrids and battery cars are a step forward, assuming anybody will buy them. But they're far from perfect: Hybrids burn gasoline, making air pollution. Batteries run down, and even though battery cars are called "zero emissions" vehicles, they generally just move the pollution rather than eliminate it (Lovins 1995, pp.73).
On the horizon, however, is a car where "zero emissions" meets truth-in-advertising. Bye-bye catalytic converters and associated pollution-control gadgetry. In fact, it will be so long to pollution entirely. In fuel-cell cars running on hydrogen, the waste products amount to water and heat.
The fuel cell, furthermore, is a new kind of engine -- one without moving parts! Even if fuel cells burn alcohol or gasoline, they will be far more efficient than today's internal combustion engines, and will produce less carbon dioxide, the primary culprit in global warming.
Fuel cells have been producing power since the start of the space age. But bulky, expensive and relatively weak, the cells seemed unlikely to find a place under the hood of Detroit's finest.
Then, in the 1980s, Canadian engineer Geoffrey Ballard began tinkering with fuel cells in search of a cleaner way to move people and goods. Among the several possible varieties, Ballard selected the proton-exchange membrane, a technology that operates at low temperature and starts up quickly; making it suitable for a machine that would replace the Buick Road Master (Polokovic 2000, p.A1).
Like batteries, fuel cells make electricity from chemical reactions. But while batteries have a limited supply of chemical energy, fuel cells get chemical energy from the fuel, so they drive until the tank runs dry.
Like a battery, a fuel cell has a cathode, with a positive charge, and an anode, with a negative charge. The cell uses a catalyst -- often platinum -- to dissociate some electrons from atoms. These liberated