University of Vermont

Snowy Day

Winooski One Hydroelectric Plant: CEF Tour

by Katharan M Blofson, Clean Energy Fund Education & Outreach Graduate Assistant


Winooski 1 is a hydroelectric generating station just 1.5 miles from the University of Vermont in neighboring Winooski.  It spans the lower portion of the 35' Winooski Falls, which have been utilized by Burlington and Winooski for hydropower for over 200 years.   With a capacity of 7.3MW, Winooski1 produces 30 million kwH of electricity annually (about half the amount of electricity used by UVM's campus annually), which is purchased by VEPPI (Vermont Electric Power Producers), and sold to Vermont utilities.  John Warshow, a Montpelier-based small hydro developer and a partner in Winooski1, and a driving force behind the project, was kind enough to take us on an extensive—and interesting—tour of the facility.

Winooski 1 is a "run-of-river" design, with a 200’ long, 35’ high concrete dam just downstream of a historic timber crib dating from 1876, and a 125’ tailrace channel that directs much of the flow of the river through the turbines in the powerhouse.    Run-of-river facilities are generally considered more environmentally-friendly: Winooski1 does not impound a large amount of water or significantly compromise the river’s natural course through its channel.  A riverside park for public enjoyment and a fish trap to facilitate migration of species like salmon were also constructed as a part of the project. 

Image courtesy of Vermont Agency of Natural Resources

Looking down on Winooski1's fish trap: as they attempt to pass around the dam, fish are trapped in a basket and trucked up or downstream during spring migration.

Completed in 1993, Winooski1 was the first hydroelectric dam in Vermont to gain certification from the Low-Impact Hydropower Institute, a nonprofit organization that certifies hydropower projects that have avoided or reduced their environmental impacts based on eight criteria which include water quality, fish passage, endangered species protection, and recreation.  In its reissuance of Winooski 1’s certification in 2004, LIHI noted that the applicant demonstrated extraordinarily good corporate citizenship, often exceeding the requirements associated with the project’s construction and operation.  

Through the doors in a small stone building just above the dam dedicated to Rosalyn Hunneman, a longtime member of the Vermont Public Service Board and a leading advocate for renewable energy in Vermont, we descended into the inner workings of the power plant.  Through a long hallway hung with technical diagrams and equipment specifications, we passed into the control room 50’ below the river.


Diagram of Winooski1's turbine, manufactured in Germany.

The Winooski1 operators (who’ve been there since the inception of the project nearly two decades ago) monitor the plant’s operation surrounded by electronics and controls that looked a little like something out of a Dr. Who episode, and are on call 24-7.  Mr. Warshow explained how the power is produced and fed into the grid: the Winooski1 dam creates a small six acre reservoir, from which the river is redirected through a tailrace channel into its three turbines—the pressure of the water on the turbine blades (which looks like a big fan) rotates the shaft, which is connected to an electrical generator, converting the movement of the shaft into electrical energy.   The electricity is then transferred through wires in the dam and fed into the Burlington Electric Department distribution system. 

Image courtesy of Idaho National Laboratory

From the control room, we walked along a catwalk in the multi-story turbine room and then down the metal stairs to view the three big turbines up close.  It was noisy down there, with huge amounts of water spinning the massive turbines and running the generators, and we had to shout; our tour leader John Warshow advised us to save our questions until later. 

Two of the Winooski1 turbines are visible in the background. 

So how “clean” is Winooski 1’s electricity?  Big hydropower projects like those owned by HydroQuebec come under fire for their environmental and social impacts, including disrupting wildlife corridors, displacing human and natural communities by flooding massive amounts of land, producing greenhouse gas emissions, and increasing environmental pollutants like mercury.  A small run-of-river project is far less destructive than huge reservoir dams, but there are still drawbacks.  For one, there are significant environmental costs embedded in concrete production, one of the most energy-intensive of all industrial manufacturing processes, much of it powered by coal, resulting in significant carbon emissions.  Eight thousand yards of concrete (about 16 tons) were used to construct the Winooski1 dam, the aggregate in the concrete mix coming from the rock blasted from the Falls.   Materials and equipment for the plant were shipped and trucked thousands of miles.  However, after the dam is in place, hydroelectric plants produce power that is virtually emissions-free, and have a long life.  And all dams compromise habitat and migration patterns, even with the installation of fish ladders and other devices to facilitate up and downstream movement. 

On the whole, small run-of-river projects like Winooski1 have far less environmental impact than large storage dams, and once constructed produce renewable power with little or no emissions and a long lifetime of operation.  John Warshow expects that with careful preventative maintenance, the Winooski1 dam will be making electricity well into the next century:  he was first attracted to hydropower in college, when he visited one of Vermont’s first hydroelectric power plants, still in operation after nearly 100 years. 

Vermont has powered herself with water for centuries.  Early settlers like Ira Allen, who constructed the first dam at Winooski Falls in 1786, built dams along Vermont’s rivers and creeks to harness mechanical energy for saw and grist mills.  In Winooski, the Champlain and Woolen Mills processed the fine merino wool that spurred Vermont’s 19th century sheep boom; the mills, which closed in 1954, are now a focus of Winooski’s downtown revitalization efforts. In the late 19th century, electrification spurred the conversion of many of Vermont’s old dams to hydroelectricity generation. Now, nearly 10% of Vermont’s electric power is generated by 84 small hydropower projects across the state (only two others are certified by LIHI); an additional 28% of Vermont’s electricity is purchased from HydroQuebec, the world’s largest hydroelectricity producer. 

Image courtesy of the Vermont Agency of Natural Resources.          

And it could be that more hydropower is in the pipeline for Vermont.  Last month, the Vermont state Senate approved a bill that authorizes the state to work with the Federal Energy Regulatory Commission (FERC) to streamline the permitting process for small hydro projects, currently just as expensive and cumbersome as the prohibitive process for large hydropower projects.  A recent VANR report on small hydro in Vermont predicts that Vermont’s hydroelectric capacity is in the vicinity of 25 MW.   A 1993 construction price tag of $16.6 million (John told us in March 2012 that the mortgage would be paid off in two months) makes the financing of hydroelectric projects across the state seem feasible.  And with Vermont’s bountiful riverine resources and some careful environmental oversight from the state, small hydro is a promising option for renewable electricity generation in Vermont, and one that UVM could explore as it tackles how to responsibly meet the carbon neutrality goals set out in the University’s Climate Action Plan.