The Oregon Energy Facility Siting Council has approved a site certificate related to a wind energy facility with a combined peak generating capacity of up to 909 megawatts.

The site certificate authorises the certificate holder, Caithness Shepherds Flat, LLC, to construct and operate a wind energy facility consisting of not more than 303 wind turbines.

The Shepherd's Flat Wind Farm, which would span Gilliam and Morrow counties in north-central Oregon, is being described as the largest in the world.

"With the Council's unanimous approval, we have taken a large step toward meeting Gov. [Ted] Kulongoski's climate change goals by developing clean, renewable energy and reducing greenhouse gas emissions," said Michael Grainey, director of the Oregon Department of Energy.

The facility is located in Morrow County and Gilliam County south of Interstate Highway 84 and east of Arlington, Oregon, between State Highways 19 and 74. The northern and southern areas of the site are linked by the Willow Creek Valley on the east and Eightmile and Fourmile Canyons in the center. The facility is located entirely on private land subject to long-term wind energy leases.

According to the Council, Caithness Shepherds Flat has not selected the turbine types for the project, but turbine tower hub height would not exceed 105 meters (345 feet) and overall height (maximum blade tip height) would not exceed 150 meters (492 feet).

The certificate holder may construct up to 158 miles of 34.5-kV collector lines to transport the power from each turbine to the collector substations. Most of the 34.5-kV system would be underground, but aboveground segments could be installed on single-pole, cross-arm structures or understrung on the 230-kV transmission line support structures.

The power output of the facility would enter the federal Columbia River Transmission System through Bonneville Power Administration's Slatt Substation.