T&D World Magazine

BPA Releases Final EIS on I-5 Corridor Reinforcement Project

The final EIS is a significant milestone in BPA’s National Environmental Policy Act review for the siting of a potential 500-kilovolt transmission line from the Castle Rock, Wash., area to Troutdale, Ore.

The Bonneville Power Administration released its final environmental impact statement on the I-5 Corridor Reinforcement Project on Feb. 3, 2016, after more than six years of analysis and robust public involvement.

The final EIS is a significant milestone in BPA’s National Environmental Policy Act review for the siting of a potential 500-kilovolt transmission line from the Castle Rock, Wash., area to Troutdale, Ore.

The final EIS documents the completed analysis of potential impacts to a wide spectrum of human and natural environments from various potential route alternatives 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.

While the final EIS includes a thorough environmental analysis and identifies a preferred route, the final EIS is not a decision document. It does not include a decision on whether to construct the line.

“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,” said BPA Administrator Elliot Mainzer, who will ultimately make the decision to build or not.

BPA proposed the I-5 Corridor Reinforcement Project to address 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.

As a result of this congestion, the possibility of brownouts or power outages in this area from transmission constraints is increasing. BPA’s studies currently show that if electric demand, or load, continues to grow without any additional physical or operational changes, that scenario might occur as early as 2021.

In addition to considering whether to build the proposed line, for the past several years BPA has been actively exploring possible “non-wire” solutions – measures that do not involve building a new transmission line – that may address the congestion issue as part of its mission to deliver power reliably and at low cost to the Northwest.

BPA has identified some solutions that could defer the project 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.

Even so, non-wire technologies are continuously evolving, and BPA has assembled a team of highly skilled engineers and other subject matter experts to continue exploring whether these measures and their ability to meet reliability needs, whether in the short or long term – or indefinitely, if possible. Some of those non-wire solutions are described below.

  • Generation redispatch: Refers to changing which large generation sources serve the load. This may alleviate congestion by reducing the amount of generation and power being transmitted along a path to more closely match the load or anticipated need.
  • Demand response: Refers to managing the power consumption at the end user. This may alleviate congestion by reducing power consumption and pairing it with generation reduction in a location to reduce flows along the transmission path.
  • Distributed standby generation: Refers to using small diesel generators or solar power generators near the source of the load.
  • Other distributed energy resources: This includes battery storage and solar generation. Large-scale batteries near the load can be used during times of high power demand. Similarly, during times of high generation, the batteries can be used to store surplus generation that can later be returned to the power system during periods of high demand. Solar generation converts sunlight to electricity and can be scalable from residential rooftops to industrial acreage scale.
  • Energy efficiency: Refers to increasing efficiency of existing buildings or appliances to reduce electricity use.

Jeff Cook, BPA’s vice president of Transmission Planning and Asset Management, emphasized that it is unlikely a single solution exists among the non-wire solutions.

“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,” Cook said. “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.”

In the meantime, Mainzer will continue to review the merits of the I-5 Corridor Reinforcement Project along with any emerging information on non-wire solutions.

“This line would provide a long-term transmission solution, and so far, we haven’t found any other feasible and cost-effective options,” said Mainzer. “We recognize the impact and uncertainty that this potential line has on the affected communities in the I-5 corridor. But I want to be sure every potentially feasible option has been explored before I make a decision of this size and scope.”

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