Auto Energy Alternatives Down the Road

CAN battery power have much of an impact on the automobile industry? At the turn of the century, many automotive pioneers tinkered with electric-powered vehicles. But the availability and low cost of gasoline made the internal combustion engine the auto industry's power plant of choice.

The crisis in the Middle East, some believe, could change the equation. The search for alternative fuels is certain to heat up. So far, most of the emphasis has been on cleaner-burning gasoline substitutes, such as methanol or compressed natural gas (see story at left). But the electric car has some of its own fans.

In Great Britain, a small fleet of electric-powered ``milk floats'' is in use for short-range urban deliveries. In southern California, regional authorities are planning a pilot program that could utilize a thousand or more battery-powered vans.

But perhaps the most ambitious venture to date - and potentially the most far-reaching - is under development at General Motors. Starting sometime in the mid-1990s, GM hopes to begin marketing a sleek, battery-powered subcompact dubbed the Impact.

``We are moving ahead very quickly with the program,'' General Motors chairman Robert Stempel said recently. Originally planned as a gee-whiz prototype for the Los Angeles Auto Show last January, GM officials were stunned by the warm reception the Impact received. And that convinced them to begin work on a salable version.

GM engineers claim they've made a number of technological breakthroughs with Impact. It can, for example, accelerate from 0 to 60 m.p.h. in under eight seconds, faster than Mazda's Miata sports car.

But the Impact still suffers from many of the same drawbacks that caused the earliest electric cars to fall from favor.

``The energy density [in a battery] is a tiny fraction of that in liquid petroleum,'' says David Cole, director of the Office for the Study of Automotive Transportation at the University of Michigan in Ann Arbor.

There are about 120,000 BTUs of energy in a gallon of gasoline, Cole notes, about 10 times as much as can be stored in a normal car battery of equivalent weight.

Though automakers around the world are experimenting with a variety of advanced formulas, the old-fashioned, lead-acid battery is still the standby. The Impact uses 32 of them because, a corporate release notes, ``they are easily manufactured in high volume at a reasonable cost.''

The Impact's batteries last about 24,000 miles. So considering replacement costs and other factors, GM estimates energy costs will be twice as high as for a comparably sized gasoline-powered car.

That equation could change in a hurry if oil prices continue rising, more so if Congress enacts a national energy policy containing an import oil tax.

But there are other limitations that would likely frustrate most American drivers, who are used to jumping in their cars and making fast runs across vast expanses of highways.

The Impact prototype delivers only about 125 miles on a charge, less than half the range of a tank of gas. And even the best battery cars currently need hours to recharge.

``No matter what we wish and hope ... the technology just isn't right yet,'' cautions William Pochiluk, chief auto analyst with Autofacts Inc., in Paoli, Pa. That's not to rule out electric cars entirely.

One promising concept is known as a hybrid, such as another GM program dubbed Project Freedom. The name is appropriate because the proposed vehicle wouldn't need to be tethered to recharging stations. One example of a hybrid is the diesel/electric railroad locomotive. Freedom combines both a conventional gasoline engine and four electric motors.

The gasoline engine would likely be a small, two-stroke design running at extremely high speed, possibly using an alternative fuel, such as methanol. That would maximize power, while minimizing emissions and stretching fuel economy.

Instead of being connected to a transmission, the engine would turn a high-efficiency generator. That generator would, in turn, charge the car's batteries and also send current to the electric motors, one in each wheel.

Researchers at the University of California at Berkeley are studying ways in which a moving vehicle could siphon current from a grid or track hidden beneath the road surface.

That, of course, creates more problems. A vehicle would only be able to travel where an electrified roadbed has been laid, unless the car carried lots of batteries on board.

Ultimately, the goal is to come up with a highly efficient and safe battery storage system that could contain as much energy as is packed into a gallon of gasoline.