BELFAST, Maine — Perched on a desk in Cathy Gleeson’s Belfast office is a mascot of sorts: a friendly looking plush beaver, a good choice to watch over the small, family-owned hydropower company, she says.

But if the city of Belfast acts on its option to buy Goose River Hydro and its series of three power plants and five dams from Gleeson, the beaver might have to switch its allegiances.

“It would be really nice to know that these stations would keep on generating electricity for Belfast,” Gleeson said Friday.

The series of dams located on a 10-mile stretch of the Goose River between the southern outlet of Swan Lake and Belfast Bay has a long history. More than 100 years ago, there were 33 dams that used and reused the tumbling water to generate power that made axe handles, ground grain, milled lumber and made leather board for Maine’s shoe industry. Beginning in the 1880s, the water also began to make electricity for the Pen Bay Electric Co.

When Gleeson and her late husband, Larry Gleeson, looked at the properties in 1977, most of those old stone dams had deteriorated into ruins. But the ones that remained intact, once modernized, were able to generate as much as 1.5 million kilowatt hours of electricity per year.

It’s a number that piqued the interest of Belfast Economic Development Director Thomas Kittredge.

Every year, the city spends from $150,000 to $225,000 on its electrical bill. About half of that money pays for the electricity at Belfast’s wastewater treatment plant. Altogether, the city buildings use 1.6 million kilowatts of electricity per year, he said.

If Belfast decides to purchase Goose River Hydro and upgrade and repair the facility so it can make as much electricity as possible, the city could enter into an agreement with local provider Central Maine Power under the utility’s “net metering” regulations. Those would allow Belfast to send its electricity back into the pool in exchange for a one-to-one reduction in the city’s energy bill.

“We’re not trying to be a utility,” Kittredge said. “Our goal would be to offset as much of that power as possible. It makes more sense for us.”

Generating green, renewable energy would also be a good fit for the city, and that’s not the only benefit, he said.

“It’s a great hedge against potential rising energy prices, too,” Kittredge said.

Rising energy prices was one reason why Larry Gleeson, a mathematician and executive at Philadelphia’s Sun Oil Co., became interested in hydropower in the first place, Cathy Gleeson said. The energy crisis of the 1970s, precipitated by Middle Eastern wars and rising prices, meant that alternatives to oil became more and more attractive.

The Gleesons purchased the mostly abandoned series of dams on the Goose River in 1977, moving their family into the old office for the Sherman & Co. leatherboard mill, which had recently burned.

They showered under the waterfall from the Mill Dam and slept in sleeping bags on the office floor while working to get the hydropower dams running.

“Nothing seemed too crazy then,” Cathy Gleeson, an English teacher and social worker by training, reminisced jokingly. “Hydropower, brain surgery — we’ll give it a go.”

Although building new dams likely would have been too difficult because of regulatory changes in the United States, resuscitating the old ones was possible. They followed the guidelines of the Federal Regulatory Commission and also worked with other agencies regarding fish and wildlife and also historic preservation.

“It was a good family business,” Cathy Gleeson said.

Her husband, who died suddenly in 2009, really loved the dams.

“It made a lot of sense, using a renewable energy source,” his widow said.

But Gleeson, who did not rveal her age, said she is ready to move on. Her grown sons and their families are spread around the country and being the “dam lady” can tie a person down.

“You can’t ignore them,” Gleeson said.

Water levels along the way need to be continually checked, she said. The recent heavy spring rains caused her to bring the water level in Swan Lake down to a level she’s comfortable with — 60 inches down from the top of the dam.

The dams need work: There are holes in several of the penstocks, the large pipes that bring water to the turbines.

Kittredge said the estimated cost to upgrade the facility will be “multiples” of the $125,000 Gleeson wants to sell it for.

The city now is paying $27,300 for an engineering study to determine the repair costs, operating costs and actual generating capacity for the hydroelectric system.

Belfast City Councilor Michael Hurley said the city is “cautiously approaching” the purchase of the hydropower plant.

“I think the devil’s in the details,” he said. “We want to make sure it’s a good investment for the city of Belfast.”

If the numbers hold up, such a purchase would make economic sense.

“Saving the taxpayers money after a few years — that’s a good thing,” he said. “I think everybody has the idea we want to be sustainable. But really, it comes down to money.”