PacifiCorp wants two hydroelectric plants

Projects would create four reservoirs near Glenrock

     PacifiCorp has filed applications with the Federal Energy Regulatory Commission in hope of  building two separate hydroelectric pumped storage projects outside of Glenrock.

The projects, if both were to be built, would create four reservoirs – two in canyon/mountainous areas above Glenrock and two in lower elevations on either side (east and west) of the town.

The current application is a request from PacifiCorp to study the feasibility of the projects. The length of the requested studies would be 48 months. According to the application filed with FERC on Oct. 13 but released for public comment last week, “It is PacifiCorp’s intent with (the applications) to evaluate the projects(s) to meet current renewable energy system needs for energy storage.”

The first application is for the proposed Rocky Ridge Pumped Storage Hydroelectric Project, a closed-loop pumped storage project to be located south of the town of Glenrock, about 11 miles south of Meadow Acres. This project would be built in Converse and Natrona counties.

Three alternatives are being considered for the Rocky Ridge Project. Alternative 1 would be located about seven miles southeast of Glenrock and consist of an upper reservoir in the headwaters of a creek flowing into a lower reservoir through electrical generators connected to a transmission line at PacifiCorp’s Amasa substation.

An underground pipeline would divert water from the North Platte River near Glenrock to the project for initial fill and maintenance refill. But the majority of water would be pumped back up and recirculated from the lower reservoir to the upper reservoir and back through the generators.

The majority of the facilities for Alternative 2 would be located about three miles southwest of Alternative 1 and be basically the same process in a different location. 

Alternative 3 would be located about three miles southwest of Alternative 2. 

The estimated annual generation of the Rocky Ridge Project would be 1,460 gigawatt-hours. The Rocky Ridge project would be located in part on federal, state and private lands.

The second FERC application is for PacifiCorp’s proposed closed-loop Box Elder Pumped Storage Hydroelectric Project and would be located about 10 miles southeast of Glenrock near the existing Dave Johnston plant, the North Platte River, Box Elder Creek and Hunton Creek.

If it’s built, the proposed project would also include an upper reservoir with enough storage for eight hours of electrical generation, a lower reservoir, pumping/generating units with a maximum capacity of 500 megawatts (1,390 gigawatt-hours annually), a new transmission line connecting the powerhouse with the regional transmission grid and a new, underground pipeline.

Like the first project, this one would use North Platte River to fill and, as needed, replenish water for the reservoirs.

 There are two alternatives under this application, with differences in the sizes of the reservoirs.

The primary substation the project would connect to is at the existing Dave Johnston plant, which was constructed in 1970 and is part of the transmission system owned and maintained by PacifiCorp. DJ is scheduled to be shut down in 2027.

According to the application, “Water is anticipated to be sourced utilizing a portion of the water rights currently held by (PacifiCorp) in the North Platte River at the Dave Johnston power plant five to eight miles away. Water from this source would be conveyed to the project through an underground pipeline. During the study phase of the project, (PacifiCorp) will create a water balance model . . . and review existing water sources to determine if other supplemental sources are available, including additional water from the North Platte River or from Box Elder Creek.”

More information on the Rocky Ridge Project (docket number P-15244) or the Box Elder Project (docket number P-15238) can be viewed or printed on the FERC eLibrary at http://www.ferc.gov/docs-filing/elibrary.asp