Sempra U.S. Gas & Power, a unit of Sempra Energy, and BP Wind Energy announced plans to jointly develop a fifth wind generation project on the Hawaiian island of Maui, the companies said May 17.

The project for a 21 megawatt farm with eight wind turbines will generate sufficient power for about 10,000 homes. It is slated to begin construction by the end of the second quarter, and should begin operating by the end of 2012, Sempra said.

In January, the two companies announced an expansion of their partnership by agreeing to invest $1 billion to build 560 megawatts of wind power generation units. In addition to Hawaii’s Auwahi Wind Farm, the companies are building wind farms in Kansas, Pennsylvania, Indiana and Colorado.

The power output from the Maui farm has already been sold under a long-term agreement to Maui Electric Co. Hawaii has set a goal of obtaining 40 percent of electricity from renewable sources by 2030, Sempra said.