GREENBURGH — The town is considering joining 11 other Westchester municipalities in purchasing wind-generated power from an upstate wind farm — but concerns that doing so may be technically illegal have held up the decision.

Supervisor Paul Feiner has been a vocal advocate of the proposal, which would buy 3 percent of the town’s annual electricity needs from Community Energy Inc., a company based in Wayne, Pa., that owns the output of the farm’s 20 massive turbines.

The farm is owned by Enel North America, a utility company than owns a number of renewable-energy plants in North America.

Thus far, more than 30 municipalities across the state have agreed to purchase wind power in bulk from Community Energy, including 11 communities in Westchester: Ardsley, Bedford, Briarcliff Manor, Croton-on-Hudson, Lewisboro, New Castle, North Castle, North Salem, Pound Ridge, Tarrytown and Yorktown.

Many of those municipalities have elected to purchase 30 percent to 50 percent of their energy from Community Energy. In 2005, Pound Ridge will begin buying 100 percent of its electricity from wind power, according to Deputy Supervisor John Powers.

The growing trend follows concerted efforts by Gov. George Pataki and lawmakers to increase renewable energy sources, particularly wind, in New York state. This summer, Pataki said the state would derive a quarter of its electricity from sources such as wind, water and solar power by 2013.

Ongoing protests against the Indian Point nuclear plants by county residents has added to the movement, with officials citing the plant as a prime reason to seek out new sources of electricity.

At a Town Board meeting last week, Feiner spoke at length in support of the proposal to purchase 3 percent of the town’s energy from Community Energy. But board member Steve Bass pointed out that state law appears to prohibit municipalities from paying a premium for utilities, instead mandating that they accept the lowest bid.

Other board members agreed with Bass, and the board put off any decision until the town attorney researches the matter. All made a point of expressing support for clean, renewable energy but said their concern was legal.

“It would be a concern of mine if we were knowingly doing something that is prohibited by state law,” Bass said yesterday.

Municipal and state officials are reluctant to say whether the purchase of wind energy, which costs about 2 percent more than conventional sources, is in fact a violation of state law.

Assemblywoman Sandy Galef, D-Ossining, has sponsored a bill that would explicitly permit municipalities to spend up to 15 percent more to purchase electricity from renewable energy sources. The legislation has passed the Assembly, but has yet to come to a vote in the Senate.

“We’re trying to be sure everyone is doing it in a legal format,” she said.

Dan Weiller, a spokesman for state Comptroller Alan Hevesi, said only that Hevesi supports the pending legislation.

“On this issue, Comptroller Hevesi believes that local governments should have the option to buy energy from renewable sources, even when the cost is moderately higher,” he said.

Yorktown Supervisor Linda Cooper pointed out that municipalities often do not solicit bids for energy anyway, and said town officials contacted the comptroller’s office before making a decision.

Feiner reiterated his belief yesterday that the town can move forward immediately.

“My feeling is that the governor’s office actually has been honoring communities that have participated in this,” he said.