BANGOR – The Maine Board of Environmental Protection voted Thursday to impose $600,000 in fines for air pollution violations at wood-fired power plants in Chester, Ashland and Livermore Falls.

Without debate, the board unanimously accepted a recommendation by the Department of Environmental Protection for fines for Alternative Energy Inc.

The DEP said the fines stem from violations of the company’s air-quality licenses at the three plants and failing to meet certain reporting requirements. Some of the violations date back to 1995.

Consent agreements called for penalties of $134,000 for violations at the Chester site, $276,000 at Livermore Falls and $190,000 at Ashland.

Alternative Energy President Chris Hutchins said the company agreed to pay the fines recommended by the DEP. The Ashland and Livermore Falls plants since have been sold to a Quebec-based company called Boralex Inc.

Alternative Energy shut down the Chester plant in April and surrendered its DEP license in August.

The company’s general manager, Tim Fitzgerald, said the plant was closed because the price of wood fiber has increased substantially.

The Chester plant had the capacity to produce 15 megawatts of electricity, enough to provide the needs of 20,000 homes. It is to be dismantled and its parts sold.

The cost per megawatt-hour to run the Chester plant was about twice that of the Ashland plant, which produces 34 megawatts of power, said Fitzgerald.

Of the total fines, about 75 percent were the result of some employees failing to pay attention to details in managing the three plants, the general manager said.