The Bonneville Power Administration recently finished a major step in its multi-year analysis of the need for a 500 kilovolt transmission line, running from Castle Rock, Washington, to Troutdale, Oregon.
The agency announced Thursday the completion of the final environmental impact statement for what has been dubbed the I-5 Corridor Reinforcement Project. This comes after more than six years of analysis, of the 79-mile line that would pass through parts of the Camas-Washougal area.
The final EIS documents the completed analysis of potential impacts to human and natural environments from various potential routes that total more than 300 miles in length. BPA addressed nearly 10,000 comments during the EIS process and worked with landowners and others to obtain input for the analysis.
“The major conclusions remain roughly the same as the draft EIS. Identification of the preferred route is the same,” said Project Manager Mark Korsness, during an interview on Thursday. “We worked with land owners over the two to three years and made some important changes to help reduce impacts.”
According to the BPA, the preferred Central Alternative using Option 1 “provides a way forward that would limit project impacts and disruptions across a broad array of communities and neighbors, manages costs to ratepayers, and achieves the goal of preserving transmission system reliability for everyone in the I-5 area in the future.”
BPA officials have stated that there are 327 homes within 500 feet of the Central Alternative.
If built, it will be the BPA’s first new north-south transmission line in the Vancouver-Portland metropolitan area in 40 years.
Camas government officials had pressed the BPA to have the high voltage utility lines buried, citing concerns about the impacts to the community’s surroundings, and health issues.
According to the BPA, however, a third-party study indicated that an underground transmission line was not feasible due to issues with cost and reliability.
The EIS states that the cost of undergrounding is typically 10 to 20 times more expensive than overhead lines. In addition, it is also difficult to keep high voltage underground transmission cables from overheating, which can cause failure.
“It just wouldn’t make sense for us to spend all of this money on a new line in large part for reliability, then sacrifice part of it for undergrounding,” Korsness said. “The cost just got really high.”
BPA Public Affairs Specialist Kevin Wingert stressed that the final EIS does not include a decision about whether to construct the line.
“This is a very large project,” he said. “BPA’s administrator, Elliot Mainzer, really is dedicated to performing the fullest due diligence we possibly can to ensure that, whether we build or don’t build, the decision is predicated upon making the right decision for the region.'”
Mainzer is not expected to make that determination before late 2016.
“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,” Mainzer said.
BPA engineers have been looking at and will continue to explore possible “non-wire” solutions — measures that do not involve building a new transmission line — that may address the congestion issue.
Some solutions have been found that have allowed the need for the project to be deferred until 2021. However, to date BPA has been unable to identify any combination of non-wire measures that would address congestion and maintain transmission reliability in this corridor for a longer term and that would be operationally, commercially and economically feasible.
“It’s important to also remember that any solution we arrive at will have a cost associated with it, and not all solutions are equal in terms of the benefit that they provide to our customers and constituents,” said Jeff Cook, BPA vice president of transmission planning and asset management. “Part of the ongoing analysis is whether one of these options, or a combination of them, might help address the congestion problem and what potential trade-offs BPA and the region would face as a result.”
Original estimates in 2012 indicated the project would cost $459 million. However, a more complete analysis that takes into account terrain have now bumped that number up significantly to $722 million. If Mainzer gives the project the green light, work would take five to six years to complete.
BPA proposed the I-5 Corridor Reinforcement Project to address what it describes as a growing transmission congestion problem in southwestern Washington and northwestern Oregon. While there is enough power generation in the region to meet energy demands, the existing transmission lines that deliver the power from other parts of the Northwest are becoming increasingly constrained in their ability to move that power during periods of high electricity use.
According to Korsness, while the formal comment period is complete, officials will accept public input throughout the life of the project.
“This is a challenging project,” he said. “We appreciate people working with us because we think we can make better decisions because of it. So, don’t be shy about contacting us.”
For more information on the I-5 Corridor Reinforcement Project, including an interactive map, visit www.bpa.gov/goto/I5.