More than three years after issuing a draft environmental impact statement (EIS) on the I-5 Corridor Reinforcement Project and after receiving more than 10,000 comments on the project, the Bonneville Power Administration (BPA) on Feb. 3 issued a final EIS for the planned 500-kV facility.
The project, which would increase the north-south transmission capacity in southwest Washington and northwest Oregon, has been in the development stage for many years, with BPA modifying existing facilities and taking other measures in the past to defer the need for the new line and two new substations.
The final EIS marks a major milestone “after more than six years of analysis and robust public involvement” on possibly adding a 79-mile line from Castle Rock, Wash., to Troutdale, Ore., at a cost of about $459m, BPA said.
In its Feb. 3 statement on the final EIS, in a Feb. 3 video presentation by BPA Administrator Elliot Mainzer and in the final EIS itself, BPA emphasized that it has not made a decision to build the project as it considers various non-transmission alternatives.
Those alternatives include generation redispatch – which refers to changing the generation sources to serve load in the region to ease transmission congestion – in addition to demand response resources, distributed generation near load centers, other distributed resources such as large-scale batteries in combination with solar power facilities and increased energy efficiency.
“Before we make a decision, [BPA] 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 in the statement, adding that he does not expect to reach a decision before late 2016.
BPA proposed the I-5 project to address transmission congestion and reliability concerns in the area, noting that there is enough generation to meet demand, but the ability to move that power during periods of high demand is being constrained. BPA said that studies currently show that if demand continues to grow without any physical or operational changes to the system, the transmission constraints could lead to brownouts or power outages as early as 2021.
In the final EIS, BPA said that construction would take five years, making for a tight construction timeframe if a decision is reached in late 2016.
“It is a tight timeline, but should we decide to build, we would employ additional non-wire measures and take any needed operational steps to maintain reliability during any ‘gap’ between the need [date] and in-service date,” a BPA spokesperson told TransmissionHub Feb. 5.
The non-wire technologies are continuously evolving, “and BPA has assembled a team of highly skilled engineers and other subject matter experts” to continue exploring those measures and their ability to meet reliability needs, BPA said in the statement.
The BPA administrator will make the final decision on whether to build the project, which is typical for such projects, the BPA spokesperson said. That decision would come in a record of decision, which also would identify the route alternative that would be constructed.
The final EIS is voluminous in its analysis of potential impacts to a wide spectrum of human and natural environments from various potential route alternatives, addressing 10,000 comments received during the EIS process as BPA worked with landowners and others to obtain input.
Addressing the time between the draft EIS and the final EIS, the BPA spokesperson said there is no “normal” period between documents, but that more than three years “is on the longer side,” pointing out that BPA received about 3,000 comments on the draft EIS and that it used the time to address comments and work with landowners along the preferred route.
As it did in the draft EIS, BPA said its preferred route is the Central Alternative, using Central Option One. The final EIS examined four routing alternatives – West, Central, East and Crossover – for the line, and each alternative included three routing options. The alternatives vary in length from about 67 to 80 miles, with BPA using a 150-foot right of way (ROW) to install lattice steel towers.
The West Alternative would be located in more urban and developed areas and would use mostly existing ROW, while the Central and East Alternatives would be in more rural and undeveloped areas on mostly new ROW, and the Crossover Alternative would use a combination of existing and new ROW.
“While it is neither the least expensive alternative nor the easiest to construct, the preferred alternative 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 said in its explanation of the preferred route.
The West and Crossover Alternatives would have more of the project adjacent to existing BPA lines, “which inherently decreases reliability because it increases the likelihood of losing more than one line at a time,” BPA said.
Similarly, although the Central Alternative and Central Option One is not the least-cost option, with an estimated cost of $459m, it is not the highest-cost either and it provides advantages that make it the preferred choice, BPA said.
For example, many members of the public and elected officials urged BPA to limit impacts to residences, schools and highly populated areas, and the Central Alternative has 327 homes within 500 feet, while the West Alternative has 3,032 homes within 500 feet.
In addition, the preferred alternative avoids many small, rural parcels of private land by crossing significant lengths of land held by firms such as Weyerhaeuser, PacifiCorp, Longview Timber and the Washington Department of Natural Resources, BPA said.
If a decision is made to build the project, the transmission line and substations would be built by two or more construction contractors, BPA said.
The final EIS includes numerous mitigation measures to lessen the impact on the environment and natural and cultural resources, along with human health and safety, socioeconomics and transportation should the line be built.
Addressing the need for the project, the final EIS said the project would alleviate transmission congestion stemming from growing load in the Portland, Ore., and Vancouver, Wash., metropolitan area, along BPA’s South of Allston (SOA) transmission path. That SOA path has been getting more and more constrained as populations have increased and the last high-voltage transmission line in the area was built more than 40 years ago, the document noted.
“In addition, power flow patterns on BPA’s transmission system are shifting and stressing the system in ways not originally envisioned,” including new generation connecting to the BPA system north of the SOA path and, to a lesser extent, power transfers from Canada through the Northwest to load centers south of the Portland/Vancouver metro area, the final EIS said.
For several years, BPA has taken steps to reduce congestion in the I-5 corridor without building new lines, upgrading existing facilities and maximizing transmission capacity, but “these operational procedures do not create additional capacity on the system” and preserving reliability on the SOA path “will become even more difficult and less effective because of the continually growing economy and population in the metro area and the increasing amount of industries relying on steady, uninterrupted power,” BPA said.
Adding the new facilities also would allow BPA to schedule outages on existing lines, which is necessary to perform critical maintenance but currently challenging to arrange, according to the final EIS.
As BPA considers its options and examines non-wire alternatives, it is unlikely that a single solution exists among those alternatives, Jeff Cook, vice president of transmission planning and asset management at BPA, said in the statement.
“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,” he said.
“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 in the statement. “I want to be sure every potentially feasible option has been explored before I make a decision of this size and scope.”