As Vineyard Wind moves forward with negotiations to build a wind farm south of the Vineyard, the last symbol of Cape Wind may soon come down.

A landmark energy bill passed in the final hours of the legislative session Sunday opens the door to offshore wind energy, but prevents Cape Wind from competing for state-required energy contracts.

The future of the Cape Wind project on Horseshoe Shoal was thrown into uncertainty this week when National Grid and NStar announced they had terminated their contracts to buy power from the private wind developer.

The state Department of Public Utilities has approved a 15‑year power purchase agreement between the electric company NStar and Cape Wind Associates, the company that plans to build a wind farm on Nantucket Sound.

The approval was announced this week following an eight-month adjudicatory proceeding.

Plans to develop a wind energy area in federal waters south of the Vineyard continue to move forward with the Bureau of Ocean Management (BOEM) releasing an environmental assessment and identifying five different configurations for the area.

At a public hearing last week, bureau representatives said the preferred option would be to develop an 877 square nautical mile area about 12 nautical miles south of the Vineyard, though smaller configurations are also on the table to address concerns about North Atlantic right whales and impacts to cultural resources and view sheds.

Cape Wind, which began more than a decade ago as the nation’s first offshore wind farm and has since been enmeshed in legal battles, political wrangling and untold miles of red tape, is inching closer to the day when 130 wind turbines will be in operation on Horseshoe Shoal in Vineyard Sound.

Cape Wind, the controversial 130 turbine project slated for construction in Nantucket Sound, announced last week that it will purchase property in Falmouth Harbor for its operations headquarters.

Meanwhile, the wind farm’s opposition continued its fight against the project in court.

Cape Wind, the controversial 130-turbine project slated for construction on Horseshoe Shoal, cleared its final regulatory hurdle this week when the Federal Aviation Administration determined that the project would not pose a hazard to aviation.

On the drawing board for 10 years, Cape Wind is planned to be the country’s largest offshore wind farm, covering 50 square miles in Nantucket Sound.