Micro hydro makes small-town comeback
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By GORDON DRITSCHILO Staff Writer - Published: August 5, 2007
Bennington's water may come to homes under its own power as the town looks to use hydro power for its water plant.
"(T)he turbine units will be placed in the main feed line from our surface source," Bennington town manager Stuart Hurd said. "We have essentially a gravity-fed system from our intake into our plant. Apparently, there's sufficiently hard flow that if there were turbines capturing the flow as it moves through the line, we can make power. … There's no need to construct any dams, no environmental impact whatsoever."
Bennington is one of a number of Vermont communities looking to use hydroelectric power for town garages and offices, street lights and schools.
Municipal projects are already in place in Morrisville, Hardwick, Enosburg Falls and Swanton, said Stephen Sease, director of regulatory management and Act 250 review for the Agency of Natural Resources. Fair Haven has repeatedly discussed reviving an abandoned hydro project on a municipally owned dam, and Middlebury is looking to pursue a hydro project in partnership with a local property owner.
Backers of the projects say Backers of the projects say municipal hydro-generation can help towns save money on electricity costs and move away from dependence on fossil fuels.
"Today there is a real resurgence in interest in hydro development," Sease said.
Renewed interest in hydropower is shifting the state's attitude toward dams, said Rich Smith, deputy commissioner of the Department of Public Service.
"Over the last, probably, 15 to 20 years, the state's been focused on removing dams from rivers, cleaning up dams people felt were unnecessary and people felt had a negative impact on fish habitat," he said. "Now there's a realization that some of these dams could be used on a small scale to provide power to some communities."
Large state utilities have tapped into water for power for decades.
"We own 20 facilities throughout the state, including Chittenden Reservoir," said Steve Costello, spokesman for the Central Vermont Public Service Corp. The dam at Chittenden Reservoir was created to produce electricity in 1908.
"It's obviously clean and when you have a project like Chittenden that's been going on 100 years, there's a very low cost of operation because the cost of construction has long since been recovered," he said.
In electrical generation, kilowatts or megawatts refer to output at peak production. A 1-megawatt dam functioning at peak capacity for an hour, would produce 1 megawatt-hour – or 1,000 kilowatt-hours – of electricity. A Vermont household typically uses 500 to 600 kilowatt-hours in a month.
How close to the peak a dam comes varies from year to year, and the peak can change due to changes in equipment or regulation, making a long-term average percent of peak difficult to calculate, Costello said. A dam's peak production varies from year to year as well as from changes to equipment or regulation, making a long-term average percent of peak difficult to calculate, Costello said.
Heavy rains made last year a record for hydro production, Costello said.
"We produced 237 million kilowatt hours of energy, which would have been enough to serve 20 percent of our residential load last year," he said. "That number was 25 percent better than the 10-year average."
CVPS is not looking to build any more dams, Costello said, but it is interested in buying power from those who do.
"We're always working to improve existing facilities," he said. "It's difficult to site a large-scale facility, and there are only a handful of sites where there aren't existing generation that are suitable for large-scale generation."
Between 8 percent and 10 percent of Vermont's power comes from in-state hydro generation from utility-owned dams and those owned by smaller companies that sell power to the utilities, according to David Lamont, a power planner at the Department of Public Service.
In 2004, the state had hoped to expand its in-state hydro capacity by bidding on a network of 13 dams on the Connecticut and Deerfield rivers. The 567-megawatt power network was put up for auction in 2004 after owner U.S. Gen New England went bankrupt.
The state's estimates put the value of the dams at $375 million. Vermont pulled out of the bidding when the eventual buyer, TransCanada Corp., offered $505 million.
And while the state's failed bid was a blow to hydro power advocates, experts say the state still has a great deal of untapped potential.
In a report she wrote for the Department of Public Service, Lori Barg of Community Hydro identified 300 dams that could turn out 90 megawatts.
"That's a conservative number," she said. "The estimates run up to 400 megawatts."
That is enough to provide about half of Vermont's base load, according to Barg. The state has about 80 active hydroelectric sites, with dams on the Connecticut River contributing to a total of 500 megawatts exported by Vermont each year, she said.
The financial, regulatory and environmental costs of creating micro-hydro capacity are particular to each project.
Robert Ide, the director of energy efficiency for the Department of Public Service, said it is hard to generalize about the cost of refurbishing dams.
"There is no average," he said. "They're just so unique."
Lamont said that even a price range is difficult to give due to site specificity and economies of scale.
"At a minimum, you're probably looking at $2,000 a kilowatt and it can double or triple from there, especially the smaller sizes," he said. "Dam size is a function of the river. … In Vermont, dams range from 500 kilowatts up to 30 megawatts. The ones on the Connecticut River are 50, 60, 80 megawatts."
Bennington's Hurd said construction costs at the water plant are estimated at $175,000 and the town is looking into grants. The water plant's power bill comes to about $30,000 a year, Hurd said. Excess electricity would be sold to the grid.
"I think we're projected to pay for the cost of the project in something like five years," he said. "Assuming six to eight months to get everything permitted and grants in place, we wouldn't be looking at construction until around this time next year, if we're lucky."
Sease said the regulatory process varies widely from project to project, but all hydro projects are subject to federal regulation. The Federal Energy Regulatory Commission requires that developers obtain a water quality certification from the state.
Sease said his department works closely with developers to help them understand the process and to figure out what sort of studies will be required.
"In our view, and this is a view we've learned from hydroelectric developers themselves, is there's an informal process called the 'pre-feasibility phase,'" he said. "Our purpose is to help them understand what sort of expenses they might be facing."
A project such as the one proposed in Plainfield, Sease said, will need little in the way of study because it will do very little to change the flow of the water around the dam.
Rose Paul, The Nature Conservancy's director of science and stewardship, said that while her organization has been involved in removing old dams, it supports responsible hydro-power development.
"It all depends on the specifics, each individual proposal," she said. "Some are the right thing in the right place and others are the wrong thing."
Dams not only can damage fish habitats by changing the water flow rate, according to Vermont Natural Resources Council water program director Jon Groveman, they also can block fish from passing.
Like The Nature Conservancy, Groveman said the VNRC looks at hydro projects on a case-by-case basis. Projects like the Middlebury one, he said, have almost no effect on water flow and therefore will have little environmental impact.
Contact Gordon Dritschilo at gordon.dritschilo@rutlandherald.com.
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