Green River hydro gets 40-Year lifeline

By Guy Page

The hydro dams at the Green River Reservoir will continue to generate power for Morrisville and surrounding towns, per a Feb. 4 agreement hammered out between the local utility, the State of Vermont, and environmental groups.

Morrisville Water & Light (MWL) has been generating electricity since 1895. Its two dams generate about 5 gigawatt-hours annually, ranking 29th among Vermont’s 44 instate hydro power providers. Environmental concerns about rising and falling river flow almost forced the local utility to surrender its license and stop generating the renewable, carbon-free electricity.

However, MWL, Gov. Phil Scott and his environmental officials, and several environmental advocacy organizations announced at a press conference Wednesday that they have entered into a final settlement establishing a path for the continued operation of its hydroelectric facilities. The agreement resolves a major dispute regarding the Green River Reservoir and sets a rigorous compliance schedule for the project’s new 40-year federal license.

The Green River Dam, for those who haven’t had the chance to see it, is a large concrete arch structure, about 360 feet long and 105 feet tall — making it one of the largest dams in the state,” Agency of Natural Resources Secretary Julie Moore said Wednesday. “Together with an earthen dike, it forms the 653-acre Green River Reservoir. This is a large and complex facility, classified as a high-hazard dam, meaning that if it were to fail, it could cause catastrophic flooding and significant damage to downstream homes and infrastructure. While a recent evaluation by the Vermont Agency of Natural Resources found the dam to be in very good condition, operating a facility of this size and complexity carries significant responsibility.”

“The days of spending most of our energy in a contested battle are past us and the days of finding the path forward and the vision for what we want to be in Morrisville and Lamoille County and moving forward together with more renewable energy, with a cleaner environment, and a populace that is not having to pay for a facility it can’t use,” MWL Superintendent Scott Johnstone said. 

Green River Decommissioning Averted – Under the terms of the settlement, MWL has officially withdrawn its request to decommission the Green River development at this time. The facility’s long-term future now hinges on a VANR evaluation of Vermont Water Quality Standards for reservoirs, scheduled for completion by January 1, 2029. If this evaluation results in amended standards that permit MWL’s continued operation, the utility will seek corresponding license amendments. However, if standards remain unchanged, MWL retains the right to decommission or transfer the dam to another entity.

Operational Changes for Continued Generation – To maintain electricity generation, MWL must implement significant operational shifts at its Morrisville and Cady’s Falls developments. Both facilities will transition to “true run-of-river” mode, where outflows must match inflows on an instantaneous basis.

Because these stations are currently manually operated and lack the technology to match flows instantaneously, MWL is required to install new automated equipment. Generation will be limited to inflows that exceed mandated conservation flows and the minimum hydraulic capacity of the turbines. Specifically, the Morrisville development must maintain a conservation flow of 70 cubic feet per second (cfs) in its primary bypass reach, while Cady’s Falls requires 100 cfs.

Project Consolidation and Timeline The agreement also marks the end of hydroelectric operations at Lake Elmore, which will be removed from the project license and will no longer be used to augment downstream power production.

The compliance timeline for infrastructure upgrades is slated to begin on July 1, 2026, or upon the issuance of the new license by the Federal Energy Regulatory Commission (FERC). Construction for the Morrisville and Cady’s Falls upgrades is expected to commence in 2028, with full commissioning targeted for January 1, 2030. During the interim, MWL will operate under a temporary flow management plan to protect aquatic habitats.