Snowpack surplus roils northwest power market

Snowpack surplus roils northwest power market

Source: Missoulian
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Last winter’s big snowpack has caused some odd ripples in western electricity markets, affecting everything from wind generation to fish survival.

“California has been adding a lot of renewable energy, but that win-win doesn’t work when you have different sets of technologies,” said Ben Kujula, power division director for the Northwest Power and Conservation Council. The council oversees energy production throughout the Pacific Northwest, including major players like the Bonneville Power Administration.

“We used to have mostly thermal plants that you could turn on and off to save money,” Kujula explained in a discussion of oversupply curtailment issues. “When you turn off a wind or solar plant, you’re not saving anything, because all the cost went into building the plant. So California’s surplus impacts what we can do shipping power down south”

Add hydropower dams to the mix and it gets even more complicated. When those California plants meet the state’s electricity market needs, demand for Pacific Northwest power falls. The owners of hydro dams have contractual authority to curtail local wind electricity generators to give priority to their water-powered turbines. So far through 2017, BPA has curtailed more than 75,000 megawatt hours of electricity, which has mostly come out of the production plans of wind-power plants in Washington and Oregon.

“We end up paying for the energy twice,” NPPC Idaho representative Jim Yost said. “Once for the energy we get, and again through the curtailment.”

BPA spokesman David Wilson said the power utility turns down wind power supplies first, because they provide the lowest-cost electricity to the system.

“Anything we pay out for curtailment, has to get passed on to our customers,” Wilson said. “When we have too much generation and not enough load (electricity demand) we need to curtail some types of power generation.”

To further complicate things, BPA hydropower dams on the Columbia River drainage such as Libby Dam and Hungry Horse Dam in Montana do more than generate electricity.

Their reservoirs hold back water that might otherwise flood downstream areas in spring, and keep those areas wet later in summer. That water also fills irrigation systems that farmers depend on for crops. And several agreements and Indian treaties control water supplies for fish like Pacific salmon and bull trout.

Interfere with the expected timing of those water flows, and lots of dominoes fall. If the dams can’t run water through their generating turbines, they must spill it to keep the irrigators and fish wet. But spilled water absorbs atmospheric gas bubbles as it falls over the dam in ways that can give downstream fish a form of nitrogen poisoning similar to what human scuba divers call “the bends.” So the releases must be carefully phased or restricted to reduce dissolved gas levels.

This year’s expected runoff has already started earlier in March than previous oversupply years of 2010, ’11 and ’12. This year is forecast to exceed the flow levels of all three of those years, meaning an oversupply of potential hydroelectricity.

“When you have the California market saying, ‘We don’t need your power,’ finding a place that needs electricity is a challenge,” Kujula said. “That energy has to go somewhere.”