BOSTON — The developers of a project off the Massachusetts coast that aims to be the nation’s first offshore wind farm announced a deal Monday with Siemens Energy Inc. to make, install and maintain the project’s turbines.

Under the agreement, Siemens will build turbines for the project, as well as an offshore electric service platform.

Siemens is also providing Cape Wind with a 15-year turbine maintenance program will hire locally to fill the majority of its operations and maintenance positions at service headquarters in Falmouth.

“This is a significant milestone for this project and we’re excited about it,” Gov. Deval Patrick said in a statement. “Massachusetts will be a pioneer in the emerging offshore wind industry, which brings with it both clean energy and good jobs.”

Construction of the offshore electric service platform, which transforms the voltage of the electricity produced by the wind turbines, will be subcontracted to Cianbro in Maine.

Financial details were not publicly disclosed.

After more than a decade of opposition and permitting hurdles, Cape Wind has been cleared to build a $2.6 billion, 130-turbine energy project in Nantucket Sound off the coast of Cape Cod.

Cape Wind is in its financing phase but has already signed contracts to sell more than three-quarters of its 3.6-megawatt output.

Siemens is the world’s leading offshore wind turbine manufacturer.

“The completion and execution of the contracts between Cape Wind and Siemens brings the experience and financial strength of the leading global offshore wind supplier into America’s first offshore wind farm ensuring important energy, environmental and economic benefits for Massachusetts and the region,” Cape Wind President Jim Gordon said.