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Developers hope to see more hydropower near China Mountain

By Nate Poppino

The desert southwest of Rogerson could host a little more water in the near future, according to a proposal by a group of hydropower developers.

Symbiotics LLC, a multi-state company with offices in Rigby and Boise, is seeking permission from the U.S. Federal Energy Regulatory Commission to study building a 1,100-megawatt pumped-storage hydropower project several miles west of Salmon Falls Creek Reservoir, on China Mountain.

According to the proposal filed with FERC for the Corral Creek South Pumped Storage Project, the site would include two reservoirs storing a combined 20,000 acre-feet of water, two 200-foot-tall earthen dams and a nearly one-mile shaft with 10 turbines buried in the rock beneath the site. The project area includes roughly 1,400 acres belonging to the U.S. Bureau of Land Management – something originally overlooked by developers, who had to resubmit their permit application to correct it.

The end result, said Justin Barker with Symbiotics, would be “like a giant battery”: a system that runs water between the two reservoirs, creating power to stabilize wind and solar projects and help utilities in the region meet growing peak demand levels. Spare power from renewable projects could help power the water pump, which would consume more electricity than the site generates.

Construction costs, he said, can near $1 billion for such facilities. But developers aren’t at that point: If granted, the FERC permit will allow them to embark on three years of engineering, environmental and economic studies researching the feasibility of the project site, funded through as much as $15 million from private investors and Symbiotics.

Those studies may reveal challenges to building such a project in what’s becoming a busy area of the state. Idaho Department of Fish and Game maps show a few sage-grouse breeding sites between the site and the existing reservoir, creating possible conflicts with the struggling birds. A 185-tower wind farm is planned for the hills just to the west, though the two may complement each other. And there’s finding the water to fill the new reservoirs – though operators afterwards would only have to replenish water that evaporates, Barker said.

The initial fill would rely on water purchased elsewhere in the system, he said. But records kept by the U.S. Department of Agriculture’s Natural Resources Conservation Service confirm that Salmon Falls Creek Reservoir has been low for much of the past decade and Salmon Tract irrigators haven’t had the easiest time securing adequate irrigation water.

“That’s one of the biggest issues, is whether we can negotiate with the water-rights holders within the region,” Barker said.

If developed, the project would be one of the first pumped-storage operations in Idaho – others are proposed – and would generate more than any one dam owned by Idaho Power Co.

Those aware of the Corral Creek proposal, including Fish and Game, plan to take advantage of a current 60-day comment period to get on FERC’s mailing list for it. The proposal could be adjusted or scaled back if studies show a need, Barker said – just as long as it stays economically viable.

Nate Poppino may be reached at 208-735-3237 or

By the numbers

Here are some details of the proposed hydropower project:

Two reservoirs, storing 20,000 total acre-feet of water

Ten generators, a total of 1,100 megawatts

Eight hours of generation, 7 days a week, for 3,212 gigawatt-hours per year

Two 200-foot-high dams, 8,400 feet and 4,100 feet

A 4,700-foot shaft connecting the reservoirs

Twin Falls, ID
March 05, 2009

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