According to a study by three California researchers, an acre planted with corn for ethanol will provide far fewer miles of transportation fuel as the same acre growing trees or switchgrass, which are then burned in power plants that provide the power to charge the batteries of electric cars.

In fact, even ethanol made from cellulose, a technology that does not now exist in commercial form, is not as efficient a use of biomass as burning it in a power plant would be, the researchers found.

In a paper published in the current issue of Science magazine, Chris Field, a professor of biology at Stanford and director of the Department of Global Ecology at the Carnegie Institution, Elliott Campbell of the University of California, Merced, and David Lobell of Stanford’s Program on Food Security and the Environment, write that the size of the advantage would depend on many factors.

These include the number of miles per gallon any particular vehicle will go on ethanol, and what a battery weighs per kilowatt-hour of energy stored. As batteries get lighter, for example, it takes less energy to move them.

But the researchers estimated that a small battery-powered S.U.V. would go nearly 14,000 miles on the highway on the energy from an acre of switchgrass burned to make electricity, compared to about 9,000 miles on ethanol.