Glenrock Rolling Hills Wind Energy Project

Project Description

PacifiCorp, an affiliate of Berkshire Hathaway Energy Company (Applicant), is the developer and operator of the existing Glenrock I, Glenrock III, and Rolling Hills Wind Energy Projects (collectively “Glenrock Rolling Hills Wind Energy Project” or “Project”) located approximately 15 miles north of Glenrock in Converse County, Wyoming. The Project was constructed primarily on reclaimed coal mine lands that were part of the former Dave Johnston mine and has been in operation since January 17, 2009. The initial 237-megawatt (MW) Project consisted of 158 General Electric 1.5-MW turbines with a total height of 388 feet. In 2019, PacifiCorp repowered 126 of the turbines (the remaining 32 turbines were not repowered) and the Project currently consists of the following:

• 281.1 megawatts (MW) of wind-generated power,
• 126 General Electric 1.85-MW turbines with a total height of 413 feet,
• 32 General Electric 1.5-MW turbines with a total height of 388 feet,
• 13-mile 230-kilovolt (kV) overhead power line, connecting the Project from PacifiCorp’s Windstar switching substation to the Dave Johnston thermal energy generation facility, access roads and collection system (underground and overhead), and located on approximately 13,801.4 acres.

Potential Eagle Impacts

Monitoring conducted at the Project since 2009 has documented bald and golden eagle mortalities. Take, including killing of eagles, is prohibited by the 2016 Bald and Golden Eagle Protection Act (Eagle Act), unless otherwise permitted by the U.S. Fish and Wildlife Service (Service) . The Service has been delegated the authority to issue Incidental Eagle Take Permits (IETPs), where the take is determined to be compatible with the preservation of eagles. The Service will issue IETPs for such take only after an applicant has committed to undertake all practical measures to avoid and minimize such take to the maximum extent achievable and agreed to complete all required compensatory mitigation.

We have received an application from the Applicant for an IETP for the Project. The Applicant has developed and provided an Eagle Conservation Plan (ECP) that summarizes project design, construction and operational measures taken to avoid and minimize impacts to eagles, and results of pre- and post-construction monitoring efforts. The ECP is included in the permit application and is available to the public as an attachment to the Environmental Assessment (EA) for reference purposes.

The Service has completed an EA for the potential issuance of the permit decision under the 2016 Eagle Act regulations. The EA assesses the potential effects of issuing an IETP and a No Action alternative (i.e., do not issue a permit) on the human and natural environment. The Service’s Collision Risk Model (CRM) predicts that up to 1.43 bald eagles and up to 10.86 golden eagles could be killed incidentally on an annual basis as a result of the operation of the Project. This was partially derived using the Evidence of Absence statistical approach to inform the CRM by analyzing post-construction mortality monitoring data collected at the project site from 2016 –2019.

Project Review

The Service has an independent statutory responsibility under the National Environmental Policy Act (NEPA) to evaluate its own actions related to the Project, namely the possible issuance of an IETP. A draft EA evaluating the impact of issuing (and not issuing) an IETP for the existing Project was made available for a 30-day comment period. We did not receive any comments on the draft EA, and the Service has prepared a Finding of No Significant Impact (FONSI) and findings document in accordance with NEPA regulations (40 C.F.R § 1508.13). The IETP will be issued under the 2016 Eagle Act regulations and will authorize non-purposeful take of bald eagle and golden eagles at the Project.

News and Updates

The Service has released the final Environmental Assessment (EA), Finding of No Significant Impact (FONSI), and findings document for the issuance of an Incidental Eagle Take Permit (IETP) for the operation of the Glenrock I, Glenrock III, and Rolling Hills (also known as Glenrock Rolling Hills) Wind Energy Project (Project) located in Converse County, Wyoming. The 30-year IETP authorizes the potential take of bald and golden eagles associated with the operation of the existing 158-turbine wind energy Project, and outlines required conservation measures, post-construction mortality monitoring, and compensatory mitigation for minimizing and offsetting potential eagle take, pursuant to the 2016 regulations of the Eagle Act. PacifiCorp, doing business as Pacific Power/Rocky Mountain Power (Applicant), is the developer and operator of the existing and operating Project.

Request Documents

If you would like a copy of the documents associated with this project, contact Tomas Kamienski or Rob Doster. 

Documents available upon request: 

• Finding of No Significant Impact (FONSI)
• Final Environmental Assessment
• Eagle Conservation Plan (ECP)