The Poor Record of the Searsburg, Vermont, Wind Plant

A report on the poor performance of Vermont's Searsburg wind project was published in The Caledonian-Record of St. Johnsbury (Vt) on December 17, 2003. It is not available on line. It was written by Eleanor Tillinghast, an environmental advocate in southwest Massachusetts, and originally appeared in slightly different form in The Berkshire Eagle of Pittsfield (Mass) on November 30.

The wind project in Searsburg, a southern Vermont town of 85 people, began operation in 1997 and consists of 11 towers with a total rated capacity of 6 MW. It replaced a forested ridge top. Tillinghast examined annual reports of Green Mountain Power (GMP), the utility that owns the project (it was built by the multinational Enxco), and evaluations for the federal government by the Electric Power Research Institute (EPRI).

[Click for PDF files of GMP's annual reports: 2002 (540 KB), 2001 (600 KB), 2000 (840 KB). Click for EPRI's large PDF reports: 3rd year (1.7 MB), 2nd year (4.3 MB), 1st year (8.1 MB).

For 2002, GMP reported the plant's output as 1.2 MW in the winter and only 0.5 MW in the summer (when demand is higher). Its average annual output has consistently been less than 25% of its rated capacity and has decreased every year.

During the three years evaluated by EPRI (July 1997 through June 2000), Searsburg generated electricity, even a trickle, little more than 60% of the time. Besides the intermittency of wind, Vermont's notorious weather ("if you don't like it, just wait a minute") took its toll. Tillinghast quotes the person responsible for maintaining Searsburg: "Lightning is the big monster up here on the mountain." Lightning damage was responsible for 24% of all downtime during the three years of EPRI's study. In May 1998 one storm damaged eight turbines. In January 2000, a damaged turbine couldn't be fixed until April because a crane couldn't get up the mountain in the winter.

Wind also caused downtime, with the number of faults increasing with wind speed. Electricity output was found to decrease as wind speed increased.

On average, each of Searsburg's 11 turbines was down an average of 83 hours every month (more than 11% of the time). GMP reported a maintenance cost four times the industry norm in 2002.

Proponents of the Searsburg project said in 1996 that it would provide 0.5% of Vermont's electricity. In 2002 and 2001, it represented 0.5% of GMP's energy source, which provides about a third of the state's electricity. Its net production was 11,459 MW-h in 2002, 12,135 in 2001, and 12,246 in 2000. EPRI reported that an average of 3.3% of the power generated was used by the turbines or lost in transmission to the substation. (The Royal Academy of Engineers in the U.K. assumes 12.5% loss will occur.) It is not recorded how much electricity the turbines themselves use, nor do their meters run "backwards" to otherwise reflect net output [click here for more about this issue].

They still claim that it provides the power for 2,000 homes. In the summer of 2002, its average output of 0.5 MW would have provided an average of 250 watts for each of those 2,000 homes. Over a year, GMP's average residential customer uses 7.5 MW-h. Therefore, the plant's annual output of about 12,000 MW-h is equivalent to the electricity used by 1,600 homes. The electricity produced, however, varies tremendously and does not correlate with actual demand. The grid into which the power is fed also supplies nonresidential electricity, which uses 72% of GMP's electricity, so the annual figure should more accurately be 450 homes, and the summer 2002 figure should be 160. These are averages, however -- when the wind isn't blowing close to the ideal 30 mph, the plant is providing the power for 0 homes and businesses. [Click here for more about wind and electricity use in the U.S.]

(Developers of a wind project in northeast Vermont's East Haven applied in November 2003 to build 4 "demonstration" towers whose 6 MW of rated capacity (the same as Searsburg) they claim will provide the power used by 3,000 homes!)

The residents of Searsburg were generally supportive of the project as it was presented to them, and many of them still say it's a good thing. The site is not prominent, limiting its visual impact. GMP and Enxco now want to enlarge the plant. As John Zimmerman, Enxco's eastern regional director, is quoted in a March 3, 2003, Boston Globe article, "Wind has become a serious way to make money." They want to add 22 (or more) new 1.5-MW towers that are 1 2/3 times taller than the current ones (requiring lights day and night and much noisier). The larger project will spread to another mountain in another town. Reportedly most residents of both towns oppose the expansion. According to GMP, it may create one more full-time job.

Finally, Tillinghast addresses the challenge of wind advocates: "What is the alternative?" [It's a bogus challenge, of course, because wind power has no impact on the use of other energy sources -- click here to read how little the U.N.'s Intergovernmental Panel on Climate Change regards wind power for the mitigation of CO2] she describes the example of the Dallas-based Kimberly-Clark company cutting its energy use by 11.7% since 2000. It would require industrializing 50 mountain tops with wind plants to produce the energy saved by this one company. Vermont itself, through its office of energy efficiency, reduced electricity consumption in 2002. Tillinghast concludes, "It's time for our leaders to enforce strict pollution controls and help businesses and communities conserve energy, instead of subsidizing an unproductive technology that will forever scar our wilderness."

-- Eric Rosenbloom

More pages on this site about wind power in Vermont:
letter to The Caledonian-Record (St. Johnsbury), by Bill Eddy
letter to The Caledonian-Record, by Bill Klein
editorial by the Burlington Free Press
notes on some surveys about wind farms
comments about proposed East Haven wind project and projects in Vermont in general
letter to the Manchester Journal, by Hugh Kemper, and response by Andrew Perchlik, with commentary
outline of large wind projects targeting Vermont and vicinity
letter to the Burlington Free Press, by Eric Rosenbloom
Also: Vermonters with Vision


Country Guardian [click here] provides data from the Vestas company about their 600- and 660-KW wind turbines in three different projects over the first six months of 2002. In Christianstal, Germany, a 9.9-MW plant actually produced only 21.8% of its rated capacity, but its output was highly variable, ranging from an average of 37.4% in February to 0.3% in May. At Royal Seaforth Dock, Merseyside, England, actual production from a 3.6-MW plant averaged 29.5% over the six months, ranging from an average 55.1% in February to 0.4% in May. And in Tursillagh, County Kerry, Ireland, a 15.2-MW plant produced at 33.5% of its rated capacity, averaging 52.4% in January but only 0.3% in May.

An effort to collect all the data that the Tennessee Valley Authority (TVA) has made available about the performance of the 2-MW facility on Buffalo Mountain found that its capacity factor is typically 21%-22% [click here]. The TVA wrote in a Spring 2002 newsletter [click here]: "Although initial output has been less than anticipated, the wind turbines have functioned extremely well and have been available for production 95 percent of the time since April 2001. Gusty wind conditions and delays in the delivery of replacement parts have been the primary causes of lost production. Wind-speed variation at the site can be extreme, with wind speeds changing from less than 10 mph to more than 35 mph within a single second and bursts of up to 70 to 100 miles per hour. Under these conditions, sensors cause the wind turbines to go offline, and they have to be manually inspected before they can be returned to service."

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