Wyoming Pumped Hydro Project Facing Pushback Due to Potential Wildlife and Fishing Impacts

      Company rPlus Hydro’s proposed $4 billion pumped-water electricity storage facility at Wyoming's Seminoe Reservoir is getting pushback from wildlife advocates, biologists, environmentalists, and trout fishing enthusiasts. In a recent hearing at the Wyoming State Legislature, they warned that a primary federal permitting review by the Federal Energy Regulatory Commission is too lax on “acceptable” impacts and riddled with inaccurate assumptions promoted by the project developer.

     According to the Wyoming Tribune Eagle:

“These concerns are not theoretical for us,” Casper Mayor Ray Pacheco told the legislative panel. “Casper relies directly on the North Platte River for drinking water, wastewater treatment, recreation, tourism and the quality of life.”

     There are concerns about potential impacts to the Ferris-Seminoe bighorn sheep herd, mostly due to blasting and industrial traffic during the project’s five-year construction period. Another concern is the effects of warmer water temperatures on trout. There are also concerns that it may exacerbate the regional drought that is ongoing.

     The article notes how pumped hydro works:

“Pumped water storage” involves pumping water uphill during daytime “off-peak demand” hours for electricity when wind and solar power are plentiful and wholesale electricity is cheapest, according to rPlus Hydro. The pumped water would be temporarily stored in a to-be-constructed reservoir above the current reservoir and released to generate hydroelectricity during higher-demand evening hours.

     The upper reservoir is planned to be 13,400-acre-foot in size. The company representative at the hearing for rPlus Hydro noted:

“It’s an enormously large project to meet Wyoming’s future energy needs,” rPlus Hydro Deputy General Counsel Kevin Baker told the legislative committee, adding that it would help lower the cost of electricity. “Pumped (water) storage is actually one of the longest duration, most effective and most cost-efficient types of energy storage that’s on the market today.”

     Baggs Republican Sen. Larry Hicks argued that Wyoming is a net exporter of electricity and the project was not likely to lower in-state power costs.

     CiCi Oliver of the Ugly Bug Fly Shop in Casper, which employs 45 people and is dependent on the North Platte River fishery, noted:

“This proposal requires exemptions from existing land use and wildlife protections in order to move forward. It is my belief that if a project only works by loosening protections that were specifically created to safeguard habitat and sensitive resources, then perhaps it is not suited for the location in the first place.”

     For this project, presumably due to it being on federal acreage, the permitting agency is mainly FERC, and state regulators have little to no role in setting permitting conditions. After the FERC’s final environmental impact statement (EIS) is issued in June, state regulators may request amendments to the BLM and Wyoming Game and Fish. The project must also be approved by the Wyoming Industrial Siting Council.

     The project began development in 2019 and is expected to be in service in 2031. That is a 12-year period from proposal to operation, if it stays on schedule. According to the company’s website:

“The project will consist of one new reservoir, underground tunnels and underground powerhouse, an intake-outlet structure in Seminoe Reservoir, and a new transmission line. The new reservoir will be located approximately 1,000 feet above the Seminoe Reservoir, approximately 10,000 feet east of the Seminoe Dam. Energy for pumping, and power generated by the project, will be delivered through a new, 30-mile transmission line connecting the project with PacifiCorp’s existing Aeolus Substation, near Medicine Bow.”’

     The project schedule is given below, followed by a nicely done video detailing how the project will be constructed:

References:

 

Critics oppose Wyoming hydroelectric project, pointing to climate-driven drought crisis. Dustin Bleizeffer. Wyoming Tribune Eagle. May 30, 2026. Critics oppose Wyoming hydroelectric project, pointing to climate-driven drought crisis | Local News | wyomingnews.com

Seminoe Pumped Storage Project. rPlus Hydro (website). Seminoe Pumped Storage | The Modern Energy Hub for Wyoming