By George Harvey
In February, we published “Affordable Power for NH,” the story of a small hydro site that had been given generating capacity and was looking for power customers. The site is operated by Steels Pond Hydro under the guidance of Lori Barg, who gave us a wealth of information.
Some time back, she did an inventory of Vermont dams and other sites that could be developed to produce power for the grid. This was part of a thorough Vermont Dept of Public Service report, “The Undeveloped Hydroelectric Potential of Vermont.” It lists the potential capacity of about 300 of Vermont’s 1,200 sites, for a combined potential capacity of 90 megawatts (MW). Since the study was published, over 20 MW has been developed.
(The report is available in three parts at bit.ly/VT-hydro-reports; look under “Vermont Reports” for Lori Barg’s name. We wish we had similar inventories for other states, but what is there is mostly obsolete, and the US Department of Energy (DOE) is still upgrading it. It is safe to assume that other areas comparable to Vermont would have similar undeveloped existing resources.)
An earlier study by the DOE’s Idaho National Labs identified 149 sites in Vermont, that could potentially produce 420 MW without a single new dam. The 420 MW potential means the sites identified by the Department of Energy could be an important resource. Assuming a capacity factor of 0.50 (meaning their average output is 50% of their nameplate capacity) Vermont’s undeveloped sites could potentially produce an average of 210 MW for each of a year’s 8766 hours, to produce 1840 GWh/y. That is about a third of the electricity that Vermont uses. The sites are spread throughout the state, and could potentially boost both the economy and the resilience of any community where one could be developed. A special search tool can be found at bit.ly/hydro-prospector.
The fact that the sites already exist is also important, because Vermont already has over 1,200 dams providing everything from flood control to recreation. We do not need more infrastructure in the rivers.
Just recently, we came across a hydro site in Vermont that is currently on the market, and it provides a really great example of a very small dam that could be developed. It is a historic mill in Shaftsbury, Vermont, about ten minutes north of the main areas of Bennington. It was used by a blacksmith at one time. It has an old turbine in place, once used to grind grain. This means some permitting is not needed because the new hydro turbine would be regarded as an upgrade, rather than a new installation.
Scully Hydroelectric Consulting, in North Bennington, recently estimated that a semi-Kaplan turbine would provide 58,469 kilowatt-hours per year, with a gross value of $12,569 per year. The site could qualify for group net metering and renewable energy credits; the precise value of the electricity produced depends not only on turbine design and weather, but the decisions on how the electricity is to be used or sold.
The building is beautifully built of stone. Dating to 1823, it is full of history, but the stone walls, history, and dam are not its only attractions. It is on a lot of 8.4 acres, much of which is open. The rooms on the first floor are simply stunning; they are very large and have beautiful massive beams across the ceiling. The thick stone walls could easily be given cushions to make attractive window seats.
The stone walls are beautiful, but stone conducts heat very easily. Though one person who lived there many years found the house comfortable as it is, it might be worth while to consider insulating the building, depending on how it would be used. Another consideration is that the mill is in a flood zone and a lender would require flood insurance. Interestingly, however, while Irene brought flooding on the land, it did not affect the house.
Despite features that might be daunting to the unprepared, it looks like the exact sort of thing some people would spend a long time searching for. Hydro-electricity is not the something a person can take up quite as easily as putting solar panels on the roof, so we would expect people who have done their homework on the subject and are still looking for a dam would be up to the challenge.
The mill property in this article is listed by Josiah Allen Real Estate/Manchester. Please see the ad for the property on this page. The property listing can be seen at bit.ly/hydro-site-for-sale.