The Wild Horse Wind Power Project is located in the eastern part of Kittitas County, Washington, approximately 10 miles east of the town of Kittitas (location map). The project consists of 149 turbines with maximum installed capacity of 273 MW.

The site consists of approximately 9,560 acres of open range land. The project interconnects to the Puget Sound Energy transmission system. On July 26, 2005, Governor Gregoire approved the Wild Horse Wind Power Project. Construction began mid October of 2005 and was completed in December 2006.

In March 2007 Puget Sound Energy requested authorization to add a 500 kilowatt solar demonstration facility on the Wild Horse site. In April 2007 EFSEC approved the request. Construction was started in mid 2007 and completed in 2008.

In July 2008 Puget Sound Energy requested authorization to add 26 new turbines with generating capacity of up to 54 MW on an additional 1,280 acres. Subsequently, Puget Sound Energy reduced its request to 22 new turbines, with an additional generating capacity of 44 MW, on 960 acres. In early 2009 EFSEC granted Puget's request and amended the Site Certification Agreement to include the additional turbines and acreage. Construction on the expansion began in May 2009.

In November 2009 Puget Sound Energy completed its expansion of the 22 wind turbines and installation of the final solar panels.

The current maximum generating capacity of the facility is as follows:

Puget Sound Energy's Wild Horse Wind Project web site.