Swollen Columbia River churns so much electricity BPA
is giving some away
Published: Friday, June 11, 2010, 7:32 PM Updated: Saturday,
June 12, 2010, 8:08 AM
Water shoots back up from the flow deflectors
immediately below the spillway at Chief Joseph Dam in Washington. The
deflectors help moderate oxygen levels to protect fish when river levels
are unusually high.
Winter's snow drought has given way to a temporary flood of late
spring runoff, forcing regional managers of the electrical grid to give
away power, dial back generation at thermal plants and rapidly fill
reservoirs to maintain acceptable conditions for migrating fish.
Robust water flows in the region's rivers are typically a blessing,
creating a bounty for electricity generation, irrigation, fish passage
and recreation. Indeed, only a month ago, the
Bonneville Power Administration
was issuing dire warnings about summer water shortages.
Those shortages are likely to materialize regardless, as rain now won't
substitute for snowmelt in July and August. But early June's onslaught
of moisture has temporarily pushed the Columbia River and its
tributaries toward flood stage and taxed the hydro system's flexibility
to manage competing interests.
The prevailing pineapple express has pushed precipitation levels to 700
percent of normal in some areas of the Snake River Basin and 170 to 200
percent of normal on the upper Willamette River, said Jim Barton, chief
of water management in the Columbia Basin for the
U.S. Army Corps of Engineers.
Too much rain means too much water over the dams' spillways, and the
resulting turbulence leads to excess dissolved oxygen in the water.
That's harmful to fish, so the big dam operators in the region -- the
Corps and Bureau of Reclamation -- divert as much water as possible into
reservoirs or through the dams turbines to generate electricity.
"All the reservoirs are filling or near full, so that makes it
challenging," Barton said. "You can only store so much."
Then you generate.
"The more the dams can generate, the less they spill and the less issue
with dissolved oxygen," Barton said.
When you create electricity, however, you need to use it, immediately,
or risk an imbalance on the grid.
During the last few days, the 31 federally operated hydroelectric dams
in the region have been running full tilt, generating an average of
13,000 megawatts of electricity. That's 144 percent of their normal
spring generation -- the equivalent of adding four nuclear plants worth
of electricity generation to the regional mix.
Complicating the picture is the region's growing fleet of wind turbines,
which have been cranking out extra megawatts as the same storm cells
dumping rain into the rivers have whipped wind speeds higher.
"You can only run the turbines as fast as you can find a home for the
power," said Michael Milstein, a spokesman for the Bonneville Power
Administration, which markets the power from the federal dams and one
nuclear plant, and integrates the spikey output of the region's wind
fleet onto the grid.
To accommodate the surge, the nuclear plant at Hanford has been dialed
back to 25 percent of capacity, Milstein said. BPA has also warned wind
farm operators that it won't be accepting much, if any, unscheduled
power production.
Meanwhile, the agency has been enticing utilities to turn off their own
power plants by giving away electricity for free, or near free, at
several junctures since Wednesday.
"That's helpful to customers, as it flows through in lower power costs,"
said Steve Corson, a spokesman for Portland General Electric.
While the weekend weather is expected to be dry, it takes several days
for a slug of moisture to move through the system.
"We expect things to be returning to normal by Monday," Milstein said.
"It certainly has been a test of the system."
--Ted Sickinger
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