A new study suggests vehicles using bioelectricity are far more efficient and better for the environment than ones using biofuels such as ethanol.

Biomass, plant matter that's grown and used to generate energy, is used to create both biofuels and bioelectricity.

Researchers, in a study published in the journal Science, found currently available electric vehicles delivered more miles of transportation per acre of crops than ones that used biofuels.

"You get more transportation services by about 80 per cent if you go the electricity route than if you go the ethanol route," co-author Chris Field, director of the Department of Global Ecology at the Carnegie Institution, told CTV.ca from Washington.

"The savings in greenhouse gas emissions were even larger -- about 100 per cent across the whole set of vehicles."

For example, a small SUV powered by bioelectricity could travel nearly 22,530 highway kilometres on the net energy produced from an acre of switchgrass.

A comparable vehicle powered by biofuels could only travel about 14,480 on the highway.

Still, Field is quick to admit that there are hurdles facing both biofuel and bioelectricity production.

"It's not obvious that the technology hurdles are greater for one versus the other," Field said.

"Given the fact that there are these big technology hurdles we think it's appropriate to put investment in working hard to develop... both sectors, recognizing that at least at this point it looks like the efficiency is much better on the electric approach."

Co-author Elliott Campbell, an assistant professor at the University of California, Merced, said one of the hurdles for electric cars is that they need better batteries.

"For the ethanol pathway we need better conversion technologies... that allow us to make cellulosic ethanol at a cost-effective way on a commercial scale," Campbell told CTV.ca in an interview from California.

Campbell also said the land available to grow biomass crops is limited.

If deforestation occurs to produce biomass crops, "you don't get a greenhouse gas offset, instead you get an increase in the amount of greenhouse gases in that atmosphere," he said.

The study only looked at transportation and climate.

Campbell said researchers still need to look at water consumption, air pollution, and the economic costs of producing the alternative sources of energy.

For now, it appears that officials are more focused on biofuels.

On Wednesday, the U.S. government announced nearly $800 million in funding for biofuels research and development but not for bioelectricity.

"There is a big strategic decision our country and others are making: whether to encourage development of vehicles that run on ethanol or electricity," Campbell said.

"Studies like ours could be used to ensure that the alternative energy pathways we chose will provide the most transportation energy and the least climate change impacts."