A new study says the Washington region isn’t doing enough to encourage the use of electric vehicles.

The vehicles, which run on electric motors powered by rechargeable battery packs, could bring economic, environmental and energy security benefits, according to the report by the Metropolitan Washington Council of Governments.

But the region’s charging infrastructure and policies are not sufficient to encourage widespread adoption of the vehicles, which number about 500 in the area.

There are 133 charging stations in the region, including 36 stations in the District.

The Electric Power Research Institute projects that there will be close to a million electric vehicles, or EVs, in the United States by 2015. In the Washington area, the institute estimates, based on past hybrid-vehicle sales and manufacturing production estimates, that there could be between 15,000 to 30,000 by 2015.

“These electric vehicle types can achieve environmental goals such as . . . [reducing] greenhouse gas emissions and can contribute to achieving sustainability goals in the region,” said Joan Rohlfs, COG’s environmental resources program director, who presented the report at the monthly meeting of the National Capital Region Transportation Planning Board.

It cost about 4 cents a mile to operate an electric vehicle when charged in the region, compared with about 13 cents a mile for the typical gasoline-powered vehicle, according to the report.

“It is a new technology and it is going to take time to develop to the extend that we would like to see it,” said Claude Willis, deputy director of the Greater Washington Region Clean Cities Coalition, which participated in the development of the report. “But I think the price of gas certainly make consumers look at alternative forms of transportation.”

But to make electric vehicles practical, the area needs to develop the infrastructure, including charging stations. One of the main obstacles for consumers when considering an electric vehicle is the fear of running out of power far from a charging station.

Transportation planners say localities have to look at creating incentives such as HOV lane access, reduced registration fees, and toll exemptions. Such benefits have boosted the popularity of electric vehicles in California and Oregon.

Along those lines, Arlington County is trying to start the nation’s first all-electric vehicle taxi fleet.

“We still have a lot to do,” Willis said. “We find that many consumers know something about electric vehicles, but not enough.”