The Shepherds Flat Wind Farm in Oregon. Steve Wilson, Wikimedia.

Northwest rivers are running high as all that winter snowpack melts into spring runoff.

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And that means the region is producing too much of a good thing: carbon-free, renewable energy in the form of both dam-generated hydropower along with electricity from spinning wind-farm turbines.

That's prompted the federal government to take an action it avoided during the last four years of drought conditions: shutting down wind power.



That's something the Bonneville Power Administration did each spring from 2010 to 2012, before more recent drought conditions kept rivers running so low that there was plenty of capacity on the power grid for all the electricity that Northwest wind farms could generate.



But there's one big difference between this spring and the region's pre-drought years: California's increasing supply of solar power.



Electricity suppliers in the Northwest used to sell a lot of their carbon-free energy from wind and hydroelectric dams to California to help it meet its renewable energy goals. But now, with more solar on the grid, California's not buying as much of the Northwest's surplus.



That leaves the extra power with little place to go. Dam operators curtail generation and send extra water over the tops of dams. Wind operators are made to stop producing power. Wind power producers lose money with each day they're not generating power.

Art Sasse, director of communication and brand for Avangrid Renewables, said his company is monitoring the situation and complying with the BPA's directives.

A lot of the reason the BPA tells wind power generators to shutdown has to do with snowmelt.



"In the Northwest, the timing of the runoff is a really important phenomenon," said Ben Kujala, a senior resource analyst with the Northwest Power and Conservation Council.



It's a tough balancing act. When rivers are running too high from snowmelt and precipitation there is only so much water that can be spilled over the top of dams, bypassing turbine generators. Too much spill can harm threatened and endangered fish.



Add to that springtime winds and there could be too much power on the grid. That could cause a blackout.



This year, BPA started the wind-power curtailments in mid-March, earlier in the season than ever before.



"One of the things we saw in previous curtailments was [extra generation] during the evening hours and over the weekends, which tends to be when people are using less electricity around here. This time a lot of the curtailments have happened during the day, which is different than in the past," Kujala said.



That's likely because of California's surplus of solar energy and changing power markets, which Kujala called a "moving target."



"While there's a lot of water, there's also a lot of solar; there's also a lot of wind," Kujala said. "And all of those things are [power] generation, where you're either going to take what you can get, or you're going to have to curtail some of it."



Kujala said it doesn't look like the rivers will be quite as swollen as during the largest curtailment in 2011.



"However, we definitely look like we're going to be on-track to do as much curtailment, if not more," he said.





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