A trash-to-energy plant that takes garbage from Vermont and New Hampshire towns is defending its practice of selling the power it generates and buying cheap power to run its plant.

That practice is being challenged by Connecticut Valley Electric Co. and its parent, Central Vermont Public Service Corp.But Daniel Madigan, Wheelabrator-Claremont LP's regional vice president, said Friday that he disagreed with the complaint filed with the New Hampshire Public Utilities Commission.

He said Wheelabrator was not in violation of either New Hampshire or federal law dealing with small power producers.

"In the opinion of my lawyers, the filing was inaccurate and incorrect," Mr. Madigan said. "We are a 'qualifying facility,' and they are ignorant of the law."

Mr. Madigan said that since 1987, when the incinerator started burning trash, Wheelabrator has been selling the power it produces - about 4.5 megawatts - to Connecticut Valley at its premium rate, while buying the power needed to run the incinerator, about half a megawatt, at a much lower rate.

Connecticut Valley says the difference is worth at least $200,000 a year.

Mr. Madigan defended the company, taking issue with a comment from a CVPS spokesman that as a small power producer, Wheelabrator got the benefits of a premium rate without the regulatory oversight.

"We're not a utility that has a guaranteed profit; we don't have the benefit of a monopoly," Mr. Madigan said. "Our money is at risk."

Bruce Simons, a Connecticut Valley spokesman, said the company is confident it would get a favorable review by the New Hampshire commission.