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Aug. 14, 2020

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BPA releases final EIS on high-voltage transmission line

Power agency identifies preferred route, says final decision pending

By , Columbian staff writer
Published:

After more than six years of analysis, the Bonneville Power Administration has released its final environmental impact statement on the high-voltage transmission line that could run from Castle Rock to Troutdale, Ore.

The more than 6,000-page final EIS is a major milestone in the BPA’s National Environmental Policy Act review for the siting of a potential 500-kilovolt line.

After reviewing potential impacts to humans and the environment, fielding more than 10,000 comments from officials and local landowners, BPA officials stuck with, but made adjustments to, a preferred route that was identified in 2012.

Initially BPA estimated the project to cost about $460 million. After a further analysis, officials put the cost at about $722 million. If approved, it could take close to six years to complete the 80-mile transmission line and the roughly 150 miles of access roads.

The proposed line under the preferred “Central Alternative” starts at Castle Rock and runs about seven miles east of I-5 before veering east and crossing the Clark-Cowlitz county line near Merwin Dam. It would then run between Camas and Washougal before crossing the Columbia River and end at Troutdale, Ore.

I-5 Corridor Project Manager Mark Korsness said the cost increase is the result of more careful scrutiny of building a transmission line through the Southwest Washington terrain and includes money spent studying the project.

“This is the only line to be built west of the Cascades in the last 40 years,” he said.

BPA officials emphasized the final EIS is not a decision document, but rather a final review of the project and possible alternatives. The final decision will be made by BPA Administrator Elliot Mainzer. He doesn’t expect to reach a final decision before late 2016.

“Before we make a decision, Bonneville will continue to evaluate the circumstances around the I-5 Corridor Reinforcement Project to ensure we’re making the right investments at the right time,” he said in a press release.

If Mainzer does approve the project for immediate construction, the line could be energized by 2021. However, he could decide to postpone it or even not build at all.

“This is the start of a new timetable,” Korsness said.

BPA says the project would address growing transmission congestion issues in Southwest Washington and Northwest Oregon. Some critics of the project say the transmission line would mainly benefit customers in California.

Korsness likened the transmission line to I-5 itself, saying that just like the freeway serves people along the West Coast, so does the power line, but the biggest demand is local.

“The biggest load is in the Portland-Vancouver area,” he said.

Officials say the issue is not power production, but the ability to move it during peak demand. By adding needed capacity and completing a regional loop, BPA argues it can prevent brownouts and power outages that otherwise might occur as early as 2021.

Three-quarters of the preferred route crosses land owned by Weyerhaeuser, Weyerhaeuser-owned Columbia Timber and the Washington Department of Natural Resources . An eighth of the route falls on BPA-owned property, and the final eighth is on private land.

Korsness said he and his team met with numerous private landowners along the proposed route and “made quite a few adjustments” to minimize impacts to private property.

Korsness also said there was pressure on BPA to site the project on as much of its own land as possible, but doing so would have run the transmission line close to 3,000 homes as opposed to the preferred alternative’s 300 homes, and BPA would still have to acquire additional land. Additionally, it would have sent the lines through more wetland areas which would have required more mitigation. Finally, it would have placed the new line near the existing north-south line, thus increasing the vulnerability of the network in the event of a fire or landslide in the area.

While considering whether to build the proposed line, BPA considered other “non-wire” alternatives such as adjusting which generation stations serve peak demands; managing how users consume power; and using small diesel generators, solar panels or batteries, among other options. However, BPA says as of now no combination of alternatives would meet current or projected demands.

“This line would provide a long-term transmission solution, and so far, we haven’t found any other feasible and cost-effective options,” Mainzer said.

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