City staff warn fish‑passage upgrades and turbine replacements could cost millions; fish‑friendly turbines may reduce some costs

Matt Sullivan, Community Development director, and Deb Chisholm, the city’s sustainability department manager and former waterways manager, briefed the committee on the condition, licensing status and upgrade options for the city’s two hydroelectric facilities at Mine Falls and Jackson Mills.

"We're going to present primarily on the hydroelectric facilities this evening," Sullivan said, introducing Chisholm to walk through fish passage and other improvements.

Chisholm presented measured generation data for the plants. "Our average annual generation is just over 11,000,000 kilowatt hours," she said of Mine Falls, which she said translates to about "a little over, 1000 homes' worth of data per year." For Jackson Mills she said average annual generation is about 4,100,000 kWh, roughly "385 homes." Chisholm emphasized these are recorded generation numbers rather than theoretical estimates.

She summarized the licensing timeline: the city applied to the Federal Energy Regulatory Commission (FERC) for a new 40‑year Mine Falls license; the original license expired in 2023 and the city continues to operate under interim authorization while it awaits a final license. Chisholm said draft FERC requirements make updated upstream and downstream fish passage unavoidable and that the city has begun conceptual designs in 2025 to anticipate those requirements.

Chisholm described two upgrade pathways under study: a conventional upstream and downstream fish‑passage design plus turbine replacement, and an alternative that replaces turbines with newer "fish‑friendly" models that could allow some downstream‑passage costs to be avoided. She cautioned the analysis is preliminary: designs are at roughly 30% and a feasibility study is expected to refine eligibility and cost estimates.

On rough, early scenarios Chisholm said the city prepared placeholders for combined Jackson and Mine Falls fish passage and turbine replacement alternatives; she noted the figures were preliminary and partly placeholder values. She said a fish‑friendly turbine alternative for Jackson could reduce the modeled downstream‑passage costs by roughly $5,000,000 in that scenario if the technology and regulatory approvals prove feasible.

Committee members pressed staff on the fiscal implications. Chisholm said the combined revenues from both facilities average about $1,500,000 a year but warned that "taking on more debt service will put us in the red" and that if the city borrows for fish‑passage/turbine projects the operation would likely require subsidy from the general fund unless revenues or efficiencies improve.

Committee members also asked whether the dams could simply be shut down or sold. Chisholm and Sullivan said they are studying options — closure, sale or continued municipal ownership — but cautioned that regulatory obligations (including fish‑passage requirements) typically remain attached to the licensed project or its transfer and that selling facilities may be complicated by the additional cost of required fish passage.

Next steps: staff will complete the feasibility study and provide refined cost estimates (Chisholm expected more detailed estimates once feasibility work concludes). The committee requested a follow‑up presentation to continue the discussion on June 18 and additional ad hoc meetings were floated.

The meeting adjourned after scheduling follow‑ups.