Power proposal would use hydro to help wind

A proposal to develop further hydroelectric power in the area would store water at a higher elevation, then drop it to generate power in a scheme that would compliment the growth of wind power.

The Grand Coulee Project Hydroelectric Authority’s project would generate up to 15 percent of the current capacity of the 6,800 megawatt Grand Coulee Dam.

Speaking from his Ephrata office, spokesman Bob Stoaks called the project “theoretical” at this time and added the pre-permit process could take two to three years. It would take another seven or more before actual construction could start.

The private company filed an application in December 2011 for a preliminary permit from the Federal Energy Regulatory Commission that would allow it to study the feasibility of a “pumped storage project” using Banks Lake.

The project, defined in two alternatives, could produce about 1,000 megawatts annually to the power grid.

The additional power would help supplement power produced by wind generation when the wind isn’t blowing.

“If the system doesn’t require the added power, then it wouldn’t be done,” Stoaks stated.

The project, if done at all, would likely surpass $1 billion in cost, and, looking out 10 years, probably more, Stoaks added.

Stoaks was formerly with the Army Corps of Engineers and has been with the Hydroelectric Authority for the past year and a half. He is a power generating engineer.

Stoaks emphasized that the project proposal is so new that core samples haven’t yet been taken, and probably won’t be until the preliminary permit process passes.

The company is currently asking for input from the public and other interested organizations and agencies.

The preliminary permit would allow the agency to study the feasibility of the project and lead to public meetings and input.

The two alternatives are:

Alternative 1, called the North Banks Lake Development, calls for an intake tube to be placed near the Crescent Bay boat launch going underground 1.5 miles to a four-generator/pump plant, 200-foot by 600-foot, located some 350 to 500 feet below ground and then connect by a 350-foot vertical shaft to Banks Lake. Water would be pumped up to Banks Lake and then by vertical flow go through the power generating plant and return to Lake Roosevelt.

Alternative 2, called the South Banks Lake Development, calls for a new 312-acre lake to be developed above the canyon rim across from Steamboat Rock, called the “upper reservoir,” which would connected to four 17-foot-diameter tunnels 1,700 feet long via a 43-foot-wide vertical shaft. It would all be connected to a four-generator/pump plant, 200 feet by 500 feet some 300 to 500 feet below the ground. Water from Banks Lake would be pumped up to the upper reservoir and then drawn down by tubes through the generating plant.

Stoaks said similar projects have been built before.

“It is highly premature to provide exact information on something that the process has just been started on,” Stoaks said.