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Some of the earliest automobiles were powered by electric motors driven by batteries, but rapid advances to internal combustion engines quickly drove the heavier, range-limited EVs from the market. The pressing need to reduce air pollution together with new advanced batteries and motors have allowed EVs to reappear as a clean alternative to internal combustion vehicles. Electric drive systems are virtually non-polluting and extremely energy efficient. Whereas only about 20% of the chemical energy in gasoline gets converted into useful work at the wheels of an internal combustion vehicle, 75% or more of the energy from a battery reaches the wheels.
Another advantage of electric motors is their ability to provide power at almost any engine speed. While internal combustion engines must be revved up to high rpm to achieve maximum power, electric motors provide nearly peak power even at low speeds. This gives electric vehicles strong acceleration performance from a stop.
Ultimately it's the batteries that will determine the cost and performance of EVs. There are several major types of automotive batteries available and under development, from advanced lead-acid batteries (like those that start our internal combustion engine vehicles), to nickel-metal hydride, to lithium polymer batteries. Even the best of these, however can store only a few percent of the energy of a gallon of gasoline in the same volume. The greater efficiency of electric motors helps a lot, but the range of EVs is still limited.
Recharging is also a consideration. Home recharging systems are available, relatively simple and give EVs an added advantage. Recharging sites away from home are still scarce and the time required for a full charge can be substantial. U.S. Dept. of Energy