CONCORD, N.H. – A Florida utility said Monday it will buy 88 percent of the Seabrook, N.H., nuclear power plant.

FPL Group Inc. will pay $837 million in a sale expected to close toward the end of the year, according to a company statement.

It will buy Seabrook shares owned by Connecticut-based Northeast Utilities and United Illuminating Co., BayCorp Holdings and the New Hampshire Electric Cooperative.

New Hampshire’s largest utility, Public Service Company of New Hampshire, is a Northeast subsidiary. Spokesman Martin Murray said the sale is good news for customers, who should see rates drop about 7 percent in a few years.

Massachusetts Municipal Wholesale Electric Co., Taunton Municipal Lighting Plant, Hudson Light and Power Department, National Grid Group and NSTAR will keep their shares of the plant, FPL said.

The 1,161-megawatt plant near the Atlantic Ocean began operating in 1990.

FPL Group is the parent company of Florida Power & Light, Florida’s largest electric utility. It serves 3.9 million households in 34 Florida counties.

“This acquisition supports our strategy to become a major energy provider in the Northeast region,” said Lew Hay, chairman and chief executive of FPL Group, based in Juno Beach, Fla.

“Seabrook is a high quality and safely operated plant,” he said.

Seabrook was a major political issue in New Hampshire from the 1970s through its completion – billions of dollars over budget and years behind schedule. The mounting debts pushed Manchester-based Public Service, which owned 36 percent of the project, into bankruptcy.

The company emerged from bankruptcy around 1989 as a subsidiary of Northeast Utilities.

Public Service no longer owns any of Seabrook, but Murray said it is obligated to buy Seabrook power and its customers still pay leftover Seabrook costs, called “stranded costs,” in their monthly bills.

In a statement, Gov. Jeanne Shaheen said the sale also would reduce rates for customers of Granite State Electric Co. and the Plymouth-based co-op.

“Two years ago, when our long fight to break up Public Service Company of New Hampshire’s monopoly and lower electric rates was finally won, we expected that the Seabrook nuclear power plant would be sold for between $400 million and $500 million. It is just fantastic news for families and businesses across New Hampshire that the actual sales price for the plant will be $836 million – the highest sale price for any nuclear power plant in history.”

State Rep. Jeb Bradley, an architect of the 1996 law deregulating the electric power industry, also hailed the news.

“It’s incredibly great news for consumers and the state’s economy,” he said.

“It puts the risk of operating the plant to new owners [and] Public Service Company of New Hampshire receives $200 million more than expected in the sale, which means PSNH’s stranded costs will be amortized three years sooner,” said Bradley, R-Wolfeboro.

He said the state would reap several million dollars in real estate transfer taxes.

State and federal regulators must approve the sale, including public utilities commissions in both states.