Vermont is roiling with controversy over big wind as the state legislature considers a bill that would make wind projects with turbines over 500 kilowatts in size subject to review at the town level, something renewable energy advocates think could jeopardize the state’s goal of 90 percent renewables by 2050.
Community wind, however, seems to be humming along. A new project has popped up at a dairy farm already famous for using cow manure to create power, and another project, installed in 2011, has received a nod of approval from the U.S. Energy Department.
Both these single-turbine projects used 100-kilowatt turbines from Northern Power Systems, which is headquartered in Barre, Vermont. While small compared to the typical 1.6 MW to 2 MW turbines used in most utility-scale wind farms, these are still pretty big turbines, set on towers with a hub height of 121 feet and with a rotor diameter of 69 feet.
In 2005, this farm became the first dairy in Vermont to join a program to produce biogas — made from the anaerobic digestion of cow manure — that is used to produce electricity for utility customers willing to pay just a little bit more for “cow power.”
An added benefit of that program is that dairies – and there are at least a dozen in Vermont in it now – can then use processed digested manure to replace sawdust or sand as bedding for the animals.
The wind turbine installed this month at the farm could add about 200,000 kilowatt-hours of clean energy to the farm’s production. That’s just an estimate, but it’s based on the performance of a 100-kilowatt turbine from the same company that was erected at the Burke Mountain ski resort in Vermont in October 2011.
A case study released this month by the U.S. Department of Energy said the turbine “has an average output of just under 700 kilowatt-hours per day” and generates about 15 percent of the resort’s energy use.