NorthWestern plans additional studies in relicensing effort

NorthWestern Energy outlined their next steps toward relicensing the Thompson Falls Hydroelectric Project (Project) in a public meeting last week. The meeting, held via Zoom Wednesday, is part of the company’s effort to renew their license with the Federal Energy Regulatory Commission (FERC) before the 2025 expiration date.

NorthWestern’s proposed study plan (PSP) was filed in response to the Pre-Application Document (PAD) submitted in July of 2020, as the company received comments submitted by four resource agencies, as well as two additional agencies who requested further studies on NorthWestern’s part in order for relicensing partners to better understand the project’s effects. In a letter sent to Kimberly Bose, FERC Secretary, NorthWestern states of the 10 studies requested, the company will adopt in whole, or in part, five of those requested studies, and declined to adopt the other five. The PSP sets forth the studies NorthWestern believes will meet the information needs to understand project effects and inform regulatory analysis and licensing decisions.

While the purpose of Wednesday’s meeting was to discuss the PSP, it also allowed for NorthWestern to respond to the study requests that were submitted and to identify any outstanding issues within the PSP. Due to the COVID-19 pandemic, the Zoom platform hosted NorthWestern energy representatives and local residents with an invested interest in the future operations of the reservoir levels and access to water recreation. Two meetings were held on Wednesday, the morning meeting saw around 50 logins, while the evening meeting had around 20 viewers. Mary Gail Sullivan, director of Environmental and Lands, Permitting and Compliance served as the liaison between NorthWestern representatives and the relicensing participants attending the meeting.

In order for NorthWestern to clarify its proposal, representatives discussed nine different studies on future effects of the reservoir. Andy Welch, manager of Hydropower License Compliance at NorthWestern Energy, said of the resource areas that will be evaluated, they have found 40 different reference sites they will be gathering data from. “The first study season starts in 2021,” Welch said. The nine studies that NorthWestern representatives discussed at Wednesday’s meeting entailed: operation studies, a study on total dissolved gas, water quality, hydraulic conditions, fish behavior, the downstream transport of Bull Trout, a Westslope Cutthroat Trout Genetics study, a visitor survey, and an inventory and evaluation of cultural resources.

Operation studies will be conducted to look at the opportunity for the Thompson Falls dam to provide flexible capacity.

“We have two main goals here,” explained Jeremy Clotfelter, NorthWestern Energy superintendent of hydro operations and maintenance. “To validate and quantify flexible capacity capability and benefits of the plant under multiple operation scenarios; and evaluate the effects of flexible capacity operations and possible impacts on project resources.” The operations test that was conducted in October of 2019 brought concerns from residents when they saw water levels drop four feet, which is the maximum vitalization of reservoir elevation allowed by current FERC licensing. Clotfelter explained, based on observed resource impacts and input from local residents, NorthWestern made the decision to propose that future operations only utilize the top 2 feet 5 inches of the reservoir, rather than the current 4-foot allotment.

During the study phases, the reservoir will be maintained between full pool and 2 feet 5 inches below full pool throughout the duration. Tests will be conducted in three separate phases, with each phase spanning over seven days. A minimum of a two-week break will be implemented between phases. NorthWestern will conduct a minimum of two operations per day that would include an increase or decrease in flexible capacity for different durations. A four-hour static hold will be maintained at a half-foot reservoir increment throughout the study. NorthWestern projects the full operations study will be completed during the primary recreation season from July 1 to September 30. Resource areas that will be evaluated during these times will include operations, shoreline stability, fisheries, recreation and aesthetics, public safety, water quality, wetland and riparian habitats, and cultural resources.

Relicensing participants will have until March 11, 2021, to file written comments on the PSP with FERC. NorthWestern will consider the input from the study plan meetings and the comments submitted on the PSP and will file a Revised Study Plan in April. NorthWestern anticipates that FERC will then issue a Study Plan Determination in May.