First Wind has finalized a deal to buy 30 turbines from Siemens for its 69-megawatt Kawailoa wind energy project scheduled to break ground on Oahu’s North Shore later this year.

Boston-based First Wind said the turbines, each with a generating capacity of 2.3 megawatts, were selected as the best match for the characteristics of the proposed project site on former sugar cane land northeast of Haleiwa. The wind energy project will be the state’s largest, generating enough energy to supply 14,500 homes. First Wind said it expects the Kawailoa project to be operational in 2012.

First Wind operates the only other wind project on Oahu, the 30-megawatt Kahuku Wind Farm, which opened in March. First Wind also operates the 51-megawatt Kaheawa Phase I and II wind projects on Maui.

First Wind operates wind energy projects in the Northeast, the West and in Hawaii, with a total installed capacity of 695 megawatts and another 181 megawatts under construction. Today’s announcement represents the first Siemens turbines to be incorporated into First Wind’s fleet of turbines.