A government study concludes:

Snake River dam breaching would harm Northwest families, electric grid reliability and the global environment

Ice Harbor Dam is one of the Snake River dams integral to clean, renewable and reliable Pacific Northwest power supply.
Photo courtesy of The Bonneville Power Administration

The Columbia River System Operations Draft Environmental Impact Statement was released February 28—a dense 5,000- page document with a remarkably clear message: Breaching the lower Snake River dams would have an adverse impact on Northwest families, the global environment and the reliability of the energy grid.

The DEIS—which was developed by the U.S. Army Corps of Engineers, Bureau of Reclamation and the Bonneville Power Administration—examines a range of alternatives for operating the 14 federal hydropower projects on the Columbia and Snake rivers.

One alternative—Multiple Objective 3—was developed to evaluate the effects of breaching the four lower Snake River dams: Lower Granite, Little Goose, Lower Monumental and Ice Harbor.

The DEIS rejected MO3 because it “has the highest adverse impacts to other resources, especially social and economic effects.”

“Oregon’s electric cooperatives are pleased the DEIS recognizes the lower Snake River dams are a critical part of the Northwest’s clean energy future,” said Ted Case, Oregon Rural Electric Cooperative Association executive director. “It found that breaching the dams would have adverse effects on power costs, particularly in rural counties, while putting the reliability of our electrical grid at risk.”

The study also concluded dam breaching was counter to minimizing greenhouse gas emissions to combat global warming. Because the Snake River dams are an integral part of the Pacific Northwest power supply—powering 900,000 homes annually—the DEIS analyzed the impact on greenhouse gas emissions if most of the hydropower were replaced with natural gas.

In a region where decarbonization has become a major policy objective, breaching Snake River dams would lead to an additional 3.3 million metric tons of CO2—a staggering 10% increase in power-related emissions across the Northwest.

Even assuming replacement resources are variable renewables, such as solar with battery storage, the DEIS found an increase in fossil fuel-based generation from existing power plants would occur to maintain system reliability. This is because the magnitude and timing of the reduction in hydropower generation would occur during peak demand, requiring flexible resources to avoid blackouts.

Aerial View of Bonneville Dam
Aerial View of Bonneville Dam

According to the study, reliability of the Northwest power supply would also be compromised. The dam breaching alternative would “more than double the region’s risk of power shortages,” the DEIS concluded, adding that this could lead to brownouts and blackouts in the Pacific Northwest, harming society’s most vulnerable populations.
Those same vulnerable populations— senior citizens and those on fixed incomes—would be impacted most by the massive cost implications of breaching the Snake River dams.

Overall, the DEIS concluded breaching the Snake River dams would have long-term, major, adverse effects on power costs and rates. For example, if BPA had to replace the lower Snake River projects’ full capability with zero-carbon resources, the DEIS noted “the rate pressure could be up to 50% on wholesale power rates.”

One Oregon electric cooperative manager said a 50% increase in BPA’s rate could lead to an increase of several hundred dollars a year on his members in a rural area that has historically battled high unemployment.

The DEIS acknowledged Snake River dam breaching would create “upward rate pressure” on residential rates and would hit those hardest in counties with a strong public power presence, such as those served by electric cooperatives.
The preferred alternative option in the DEIS keeps the four lower Snake River dams in place but increases spilling water over the dams for fish passage when power generation is less valuable.

The release of the DEIS started a 45-day comment period that closes Monday, April 13.