Electric cars make sense, as Jessica Mathews points out in her op-ed article "Zero Emissions: Detroit Doesn't Have to Be the Hub" [Jan. 16]. Electric cars are quiet, more energy-efficient and produce no local pollution, although they are not "zero-emission” vehicles, strictly speaking, unless the electric power comes from nuclear or hydro energy.

Detroit automakers seem to believe that lack of a high-tech battery is keeping the electric car from becoming a commercial success. Obviously, it would be great to have a cheap, light-weight, high-power-density battery that could be recharged thousands of times without deteriorating. Without such a battery, the range of the vehicle would be less than 100 miles, requiring frequent and lengthy recharging—an impractical proposition. But the problem can be overcome, even with today's batteries, if we build a "hybrid."

In a hybrid car, the batteries are constantly recharged while the car is running. A prototype designed by Stanford students—to whom I served as an adviser—used as a charger a very small internal combustion engine, running at a constant speed with near-zero emission.

An even better scheme adds "dynamic braking," in which the energy of motion, rather than being dissipated by the brakes, is recaptured and stored in the batteries, or in flywheels or in ultracapacitors (like those developed for the Star Wars program). An added advantage is the high efficiency of the system; the internal combustion engine then has to supply just enough energy to overcome aerodynamic and road friction.

The best scheme of all substitutes a fuel cell for the internal combustion engine, making it an all electric system. The fuel cell, fed by compressed natural gas, generates enough electric power to keep the batteries charged. The system would run without noise, emit no smog-producing pollutants and—best of all—could easily triple or quadruple the energy efficiency of today's automobile. It would also drastically reduce the need for oil imports.

The White House Office of Science and Technology and the undersecretary of commerce are pushing hard for this and similar solutions to the urban transportation problem. Success may come sooner than we imagine.