BPA says a recent assessment of how the four lower Snake River dams performed during last winter shows the value they can offer the region during extreme weather.
The extreme cold the region saw, especially in early 2021, led to forced outages at Grand Coulee, John Day and The Dalles dams in January. It also impacted the generation at Chief Joseph Dam during a deep freeze in February, which was mitigated by shifting some of the facility's generation and reserves to the lower Snake River dams.
This detailed look was undertaken to help power planners evaluate the potential impacts of climate change such as extreme cold-weather scenarios, and how the federal system can respond, the agency said.
The dams, which annually produce about 1,000 aMW, are equipped to provide operational agility and flexibility, Bonneville said. This allowed them to generate more than 1,700 MW of electricity at times during the winter and to provide backup electricity and power reserves in February when equipment failure at Chief Joseph during a deep freeze impacted generation.
"Knowing we can rely on these facilities for steady energy production under normal circumstances should bring great comfort and confidence to residents of the Pacific Northwest," said Kieran Connolly, BPA's VP of generation asset management, in a statement. "Being able to rely on their operational flexibility during extreme weather truly demonstrates the value they provide to the region."
This flexibility included the ability to ramp energy production down to zero at night when power demand dropped and then quickly ramp it back up during the day.
"Year after year, the Pacific Northwest can count on service from these projects in the winter when electricity consumption is highest," said Bonneville Administrator John Hairston in a statement. "As we feel the impacts of climate change and the region builds more intermittent energy resources like wind and solar, we're seeing more evidence that these dispatchable hydroelectric facilities are vital to public safety and electric reliability for the region."