Shoshone shutdown comes at a good time
GSPI News Editor
An early start to the spring runoff is minimizing the river flow impacts of work that has begun on the Shoshone Power Plant.
Xcel Energy last week began preparatory work that will result in taking its two Shoshone turbines out of production for about two months while it undertakes an automation project at the plant.
The project also will allow for upstream water storage that could help ease the impacts of an anticipated summer drought.
The turbines are to be shut down completely starting in April, at which point Xcel will temporarily stop exercising its senior water right on Colorado River water.
That will allow other water users upstream to store water for later use on both the Western Slope and Front Range.
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It also will mean less water will flow downstream.
At other times of year, such a drop in Colorado River flows could cause concern.
Extremely low water results in a higher concentration of salts and other contaminants in the river. That can be detrimental to fish and drives up the costs for downstream communities such as Rifle to clean the river water used for their municipal supplies.
But such impacts should be minimized by the fact that snowmelt has begun entering the river.
“This is a very good time of the year to be doing this, especially this year,” said Dave Merritt, chief engineer for the Colorado River Water Conservation District, based in Glenwood Springs.
The Colorado River through Glenwood Canyon was running at about 1,000 cubic feet per second on Friday, up from about 600 cfs over the winter, Merritt said.
Divers kick off job
Xcel crews last week began doing pre-outage work in preparation for its automation project, said Dan Brown, manager of hydropower production at Xcel. Divers entered the river to install “stop logs,” which are steel pieces inserted to block water from coming into the exit or tail race of the plant.
The automation project will consist of upgrading electrical equipment and modernizing electrical switching equipment and controls, Brown said. The result will be increased reliability and the ability to better perform maintenance tasks.
Some of the equipment currently in use is so old that it’s hard to get replacement parts, he said.
Shoshone was finished in 1909. Water for the plant is diverted upstream from a reservoir at the Hanging Lake exit of Interstate 70, and sent to the plant in a three-mile tunnel.
Brown said the automation won’t result in any staff cuts at the plant. Seven full-time employees operate the hydropower plant and the dam upstream.
This marks the second year in a row that upstream water storage facilities are being able to take advantage of a decision by Xcel to not fully exercise its senior water right. About a year ago, Xcel temporarily reduced its call on river water solely to allow for more storage by other users due to the severity of the drought.
Xcel spokesman Steve Roalstad said the decision by the company to make upgrades this time of year is a good example of its desire to minimize impacts on the river.
The company angered anglers when it flushed the Shoshone reservoir last fall in an effort to wash out a buildup of sand. The flush choked the river with sediment for several miles downstream, with the problem worsened by low fall river flows and the fact that it was spawning season for brown trout.
After discussions with the state Division of Wildlife, Xcel has since agreed to try to conduct such flushes in the spring instead of fall whenever possible.
In the case of the current work, Brown noted that Xcel is losing more power production than it might during a time of year with lower flows. When the river level rises at times such as spring runoff, it is able to put both of its Shoshone turbines into operation instead of just one.
Still, the Shoshone plant is only a minor power producer for Xcel, with a capacity of 14 megawatts.
While Shoshone is down, Xcel will increase production at its Hayden and Cameo coal-fired plants to make up for the lost hydropower.
Roalstad noted that Xcel is currently not in a period of peak demand. Those peaks occur during summer and winter, during the height of the air conditioning and heating seasons.
Brown said the first Shoshone turbine is scheduled to return to service May 26, and the second one on about June 6 or 7.
Merritt said the suspension of the water call at Shoshone will make things easier for water engineers in charge of managing flows on the river. They must take into account competing water rights, and how weather conditions and water travel times impact the delivery of water downstream.
Dry times ahead
While the early start to runoff is having some positive benefits in relation to the Shoshone project, it’s not the best of news in terms of the state’s water outlook this year.
“Normally this time of year we would still be gaining snowpack and instead we’re losing snowpack,” Merritt said.
“What it means is we’re going to dry up earlier,” he said.
He said the storage that occurs during runoff is crucial to maintaining the summer river flows through Glenwood Springs that keep its rafting industry going strong.
When Grand Valley peach growers exercise their water rights, water is delivered on the Colorado River through Glenwood.
“Glenwood benefits from those peaches twice,” Merritt said.
Contact Dennis Webb: 945-8515, ext. 516
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