First Wind LLC said Tuesday it is on track to begin construction on the state’s largest wind energy project on Oahu’s North Shore by year’s end, now that it has finalized a deal to buy 30 wind turbines for the facility.

The 69-megawatt project being developed by Boston-based First Wind on former sugar cane land northeast of Haleiwa will provide enough energy to meet the electricity needs of 14,500 homes, company officials said. The project, called Kawailoa Wind, is expected to begin operating sometime in 2012.

The turbines, manufactured by Siemens, were selected as the best match for the characteristics of the project site, which ranges in elevation from 200 feet above sea level to 1,280 feet, according to the company.

"This purchase agreement with Siemens further diversifies our portfolio of wind turbines, and it enables us to deploy equipment that is both the best technological and economic fit for the project site," said Paul Gaynor, First Wind’s CEO.

The project will be built on land owned by Kamehameha Schools that was part of the Kawailoa Plantation operated by Waialua Sugar Co. before it closed in 1996. While the plantation is spread over several thousand acres, the area "disturbed" by the project will be limited to 335 acres, according to an environmental impact statement prepared for the project.

First Wind operates the only other wind project on Oahu, the 30-megawatt Kahuku Wind project, which opened in March. First Wind also runs the 51-megawatt Kaheawa Wind Power Phase I and II 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. Tuesday’s announcement marks the first time that First Wind will use wind turbines made by Siemens at one of its projects.