Each of the large panels rotates on a vertical axis and a horizontal axis. This lets the panel point directly to the sun. This increases incident energy about 40% compared to a fixed solar panel such as might be on a homeowner's roof. The anemometer at the top of each panel senses wind speed. If it exceeds 30 mph the controller flatens the panel to a horizontal position to avoid wind damage.
Because we visited on a cloudy day, the day's production of 4359 kWh of electric energy was only about a quarter of what can be achieved on a sunny day. You can see up-to-date production reports on-line, at http://www.allearthrenewables.com/energy-production-report/detail/316#view=monthly&date=2011-09-01.
The solar farm was a $12 million investment. It made good economic sense because of a 30% federal tax credit and a 30% Vermont state tax credit. Vermont established a feed-in-tariff for photovoltaic solar power, guaranteeing that electric utilities will buy the energy at $0.30 per kWh. That's about four times the average power cost, but it is spread over the cost of all energy provided by the utility to its customers. Since then the Vermont tax credit has expired and the feed-in-tariff rate has dropped to $0.24.
Generators of solar power also receive renewable energy credits (RECs) that can be retained or sold in a nascent marketplace.
Sept 20, 2011
AllEarth Renewables Solar Farm
350 Dubois Drive
South Burlington VT
At end of Dubois Drive off of Rt 116; park before the roundabout.
Offices94 Harvest Lane # 101
Williston VT 05495
Host: Andrew Savage, Director of Communications and Public Affairs
Visit here to learn about AllEarth Renewables solar power.
David Blittersdorf and his company are featured in Wentworth Institute of Technology's alumni magazine, here, and a Blittersdorf presentation is here.
Valley News' Chris Fleisher wrote about the home solar market, here.
John McLaughry's Ethan Allen Institute newsletter is critical of the subsidies that make solar power economic.