Despite numerous government agencies’ concerns about just how much water PacifiCorp will be taking out of the North Platte River, the Federal Energy Regulatory Commission (FERC) has decided to grant PacifiCorp a preliminary permit to study the feasibility of the Box Elder Pumped Storage Project, with an ultimate tie-in to the existing Dave Johnston coal fired power plant.
PacifiCorp submitted an application for a preliminary permit in Oct. 13, 2021. The decision to grant the preliminary permit was released Oct. 19.
The project, which originally had several iterations, will be located approximately 10 miles southeast of Glenrock in Converse County, on federal Bureau of Land Management land.
According to the FERC decision, PacifiCorp has proposed two alternatives for the Box Elder Pumped Storage Project, approximately 1.5 miles apart, which share a similar configuration and will connect to the same existing electrical grid substation.
Alternative 1 would consist of the following new facilities: an upper reservoir with a surface area of 161 acres created by a 2,120 foot long, 400-foot-high embankment dam; a lower reservoir with a surface area of 110 acres and a storage volume of approximately 5,222 acre feet created by a 5,400-foot-long, 60-foot high embankment dam; a two mile long steel penstock with a diameter of 25.5 feet, a 150-foot-long, 50-foot-wide concrete powerhouse/pump station located on the lower reservoir shoreline containing up to three generating/pumping units for a total generating capacity of 500 megawatts; an approximate 5.3-mile, 230-kilovolt (kV) transmission line from the powerhouse to the existing Dave Johnston substation that would interconnect to the regional transmission grid; an approximately 5.3-mile-long underground pipeline with a diameter of 24 inches diverting water from the North Platte River for construction, initial fill and annual maintenance fill (supplemental water may be used from other sources, including Box Elder Creek); and associated facilities.
FERC stated in their decision that most of the facilities for Alternative 2 would be located approximately 1-2 miles southeast of their counterparts under Alternative 1.
Alternative 2 would consist of the following new facilities: an upper reservoir with a surface area of 281 acres created by a 470-foot-long, 130-foot-high embankment dam, and similar supporting facilities as listed for Alternative 1.
The proposed hydroelectric project would be operated as a closed-loop system and generate an estimated annual average of 1,390 gigawatt-hours.
Although the preliminary permit has been issued by FERC, it does not authorize PacifiCorp to access lands and does not authorize the permittee to undertake any land-disturbing activities. PacifiCorp will have to obtain authorization and comply with all applicable laws and regulations to conduct any field studies.
If PacifiCorp determines the project is feasible, data gathered during the preliminary permitting stage can then be used to apply for a hydropower license.
As to the concerns over just how much water will be required from the North Platte River, endangered/threatened species of plants and animals, land access and access to hunting areas, FERC stated in the preliminary decision document that, “The Commission’s regulations acknowledge that full, detailed project information may not be available when a preliminary permit application is filed. To ensure that an applicant has provided adequate information to determine project effects and benefits, we require that detailed information regarding the proposed project be provided at such time as a license application is filed.”
The preliminary permit is good for up to four years from the date of issue, according to the FERC decision.