BOSTON (Legal Newsline) - The Massachusetts Supreme Court has ruled that the state public utilities department was right to deny a motion filed against a 2009 power purchase agreement involving a wind farm.

The decision is a victory for Cape Wind, a proposed 24-square-mile wind farm in the Nantucket Sound. In 2009, National Grid decided to purchase power from it, and the Alliance to Protect Nantucket Sound has been fighting its development.

The Alliance was appealing a Department of Public Utilities decision not to reopen the case. The Alliance sought to introduce unredacted copies of documents filed with the DPU by NSTAR Electric Company. DPU said the documents would not have had a significant impact on its decisions.

"The record... already did include evidence relating to the pricing of other available renewable energy resources located both outside of and within the Commonwealth," Justice Margot Botsford wrote.

"The department did not abuse its broad discretion in declining to reopen a closed record in a completed proceeding in order to accept more information on the same points."

The Cape Wind proposal includes 130 wind turbines, and National Grid has agreed to buy half of the power generated by them.

In August, state Attorney General Martha Coakley announced a rate-reducing agreement that she said would save ratepayers as much as $450 million.

The original contract between Cape Wind and National Grid called for 20.7 cents per kilowatt hour with an increase of 3.5 percent every year over 15 years. The new contract puts the starting price at 18.7 cents with the same escalation, though the price will be capped at 19.3 cents.

From Legal Newsline: Reach John O'Brien by e-mail at jobrienwv@gmail.com.