The state’s world-class tradewinds are now producing electricity for Oahu homes and businesses.

Officials from First Wind LLC, Hawaiian Electric Co. and state government will gather in Kahuku today to dedicate the island’s first large-scale wind farm. The 30-megawatt facility developed by Boston-based First Wind officially began selling electricity to HECO yesterday, allowing Oahu to join Maui and the Big Island in the effort to harness Hawaii’s famous winds.

The wind farm features a dozen 2.5-megawatt wind turbines manufactured by Clipper Windpower of Carpinteria, Calif., that are expected to generate about 83 million kilowatt-hours annually, the equivalent of 139,500 barrels of oil. That’s enough electricity to power 7,700 homes, according to First Wind.

Officials scheduled to attend the dedication include Paul Gaynor, First Wind CEO; Dick Rosenblum, HECO CEO; and Gov. Neil Abercrombie.

The turbines are on 575 acres, most of which is owned by First Wind. The three-blade turbines sit on steel towers 260 feet high, with turbine blades reaching 460 feet at their peak. Information about the electricity being generated at the wind farm will be instantaneously transmitted to HECO’s systems operation center via a microwave signal.

First Wind will sell the electricity to HECO at a fixed price of 19.9 cents per kilowatt-hour under a purchase power agreement approved by the state Public Utilities Commission in May.

The Kahuku project also has a 15-megawatt battery energy storage system designed by Xtreme Power Inc. of Kyle, Texas, that will smooth fluctuations in power output caused by changes in wind levels. It’s the first time Clipper wind turbines have been combined with Xtreme’s battery energy storage system.

While the 30-megawatt output is a small part of HECO’s islandwide peak load of 1,250 megawatts, it is part of the incremental move toward decreasing the state’s dependence on oil.

About 90 percent of the state’s energy usage comes from imported petroleum.