Cape Wind’s developer was buoyed by a key legal victory yesterday from the state’s highest court, but pushed back the construction start by another year amid persistent questions about financing for the offshore energy project.

“We’ve made predictions in the past. This project has been under development for over 10 years, and the important thing is we keep moving it forward one step at a time,” Cape Wind president Jim Gordon told reporters on a conference call. “We’re hoping that within about a year we will be able to be producing clean, homegrown energy.”

But Cape Wind’s 130 turbines won’t be up and spinning in 2012. A spokesman later clarified Gordon’s remarks, saying the plan is for construction, expected to last 18 months, to begin in 2013

After Cape Wind cleared its final regulatory hurdle in April, a company exec predicted the project would start this past fall. Since then, Cape Wind has been unable to land buyers for all of its electricity, and it lost out on a federal loan subsidy, making it harder to secure private investments.

The Supreme Judicial Court handed Cape Wind a major victory yesterday, upholding the state Department of Public Utilities’ approval of the project’s 15-year power-purchase deal with National Grid.

The electricity could cost ratepayers as much as $695 million above market prices, which the DPU deemed “expensive” but “reasonable” given the project’s environmental benefits.

The Alliance to Protect Nantucket Sound, among a group of Cape Wind critics that appealed the DPU’s November 2010 decision, ripped the SJC’s ruling as a “blow to ratepayers, businesses and municipalities.”