Malheur County could get billion-dollar energy project on Owyhee Reservoir

The Malheur County Court recently heard from the chief executive officer of a Utah firm that wants to build a power generating facility near the Owyhee Reservoir. (Rachel Parsons/The Enterprise).

VALE – A Utah company is considering construction of a new dam above Owyhee Reservoir as part of a $1.2 billion project to generate new hydro power.

The power operation could generate the equivalent of half the Treasure Valley’s peak electricity demand on a hot summer day.

Matthew Shapiro, chief executive officer of rPlus Hydro, recently outlined the project to the Malheur County Court and shared more details in an interview with the Enterprise.

The company plans to construct what’s called a pumped storage facility, which uses gravity feeding water into turbines to generate electricity.

A pumped storage facility operates on a simple concept tied to gravity.

A reservoir is constructed on high ground above an existing reservoir. A pump station, or powerhouse, with a turbine is then constructed between the two reservoirs. Pipes connect the pump station to the upper and lower reservoir and generate electricity as water moves through. During a period of low demand for electricity – such as at night – water would be pumped out of the Owyhee to the upper reservoir.

When electricity demands increase, the water stored at the upper reservoir would be released through the turbines to the lower reservoir. The turbine also acts as a pump to move water to the upper reservoir.

At the site, a new dam would measure 130 feet high by 1,300 feet, creating a 100-acre reservoir. The Owyhee Dam is about 400 feet tall.

A 22-foot tunnel would connect the new reservoir to the powerhouse, with a powerline carrying the electricity to a substation.

“You are storing energy in the form of water at a higher elevation,” said Shapiro.

Shapiro said the project, in “the conceptual stage,” is estimated to employ 300 during construction jobs and about 20 full-time staff once it is finished.

“It is something we do intend to put some engineering effort into and into environmental studies over the next several years and see where it goes,” said Shapiro.

“You are storing energy in the form of water at a higher elevation,” said Shapiro.

The final piece of the pump storage facility is the construction of a transmission line to the power grid. Except for the reservoirs, the entire project – including pipes, pump station and control room – would be underground.

The rPlus Hydro project would require “about 3,500 acre feet of water to cycle up and down,” said Shapiro.

“But it is not consumptive use. It’s just we need to secure that amount of water to move up and down,” said Shapiro.

News tip? Contact reporter Pat Caldwell at [email protected]


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