BELFAST, Maine — The city of Belfast will not own its own hydropower utility anytime soon, according to a decision made earlier this spring by the City Council.

Councilors let the option to purchase Goose River Hydro, a privately owned series of three power plants and five dams, expire at the end of March after determining that the project would simply be too expensive.

Cathy Gleeson, who owns the facilities, had offered to sell the property to the city for $125,000.

However, estimates for capital improvements and annual operating costs for the hydropower plant added up to as much as $4.6 million over 20 years, according to Belfast Economic Development Director Thomas Kittredge.

City Councilor Eric Sanders said Thursday that in the end, the numbers simply didn’t work.

“You want to go green, but you have to make sure that since it’s the taxpayers’ money, you have to allocate not only for green, but for financially responsible,” he said. “It would have been a great asset, had it financially worked, but the realistic measures to get it to where we wanted it to be were not feasible.”

The series of dams are located on a 10-mile stretch of the Goose River between the southern outlet of Swan Lake and Belfast Bay. More than a century ago, there were 33 dams on the river that used the tumbling water to generate power that made ax handles, ground grain, milled lumber and made leather board for Maine’s shoe industry.

Cathy Gleeson and her late husband, Larry Gleeson, purchased the then-rundown remaining dams in 1977. Once modernized, they were able to generate as much as 1.5 million kilowatt hours of electricity per year.

Efforts to reach Gleeson Thursday were unsuccessful.

City officials grew interested last year in purchasing the dams because city buildings use 1.6 million kilowatts of electricity per year. Belfast spends from $150,000 to $225,000 each year on its electrical bill.

Had the deal worked for Belfast, the power generated most likely would have been returned to local provider Central Maine Power’s electrical pool and used to offset the city’s energy bill.

Kittredge said that right now, Belfast is paying 12 cents per kilowatt hour. No matter how the city crunched the numbers, the costs of purchasing, upgrading and maintaining the hydropower plant would have exceeded the revenue generated.

“It ended up with a net loss over 20 years to build and refurbish and operate it, and keep it running smoothly,” he said. “It doesn’t make sense to do it unless we had a really good idea that we could break even.”