By George Harvey
A solar photovoltaic installation in Norwich, Vermont, looks as though it may set a trend. It was put on the roof of a barn at the Pirouette Farm, which not only has the solar exposure, but also the size needed to provide for a number of families. Among other advantages, it has the cost advantages of a rooftop system, but also the economy of scale of a community array.
Norwich Solar (NS) used a proprietary solar design, EZ-PV for the system. EZ-PV was developed by the company’s own designers and is the company’s unique approach to solar photovoltaic (PV) technology. It provides for pre-assembly of sets of solar panels into MetaModulesTM. The panels are fitted to their racks using jigs, which make the entire operation repeatable and measurable, more precisely than they could ever hope to be in the field. They are tested in advance by using lights and measuring output before they are brought to the installation site. Once there, they are installed very quickly, with a minimum of disruption.
All of this was very important to Robert and Mary Piro, owners of the Pirouette Farm, an equestrian center, where the array was sited. Horses can become very stressed by the noise and inconvenience that can be associated with construction. The reduced level of activity to which the horses would be exposed is a definite benefit.
The pre-wiring in the building was not a bother to the horses. It was quietly done, and they probably did not notice at all. After that, on the day the solar panels arrived, they were already out, in their regular daily activities. While the horses were going about their regular routine, a crane arrived so the MetaModulesTM could be hoisted into place. It was on the back of a truck with wide wheels, which meant that the soil under it was disturbed as little as possible. The crane lifted 32 MetaModulesTM, with a total of 180 panels, to the roof of the barn. Workers on the roof put them into their permanent resting places. Then they wired the modules to the system, while the crane packed up and left for home.
Norwich Solar uses two crane services at their installations, and they regard both very highly. The operators have received special instruction on how to do the specific job at hand and are experienced in the work. Hutch Crane Services of Stowe, Vermont, provided the work at the Pirouette Farm. NST also uses Miller Construction of Windsor, Vermont.
The installation of the assembled 60 kW’s of solar panels with the crane was done in six and a half hours. There was practically no visible indication that the crane had ever been there, aside from the work quietly done on the roof. Meanwhile, the horses were still out, going through their regular activities. Our understanding is that not a single horse complained about the stress caused by the installation.
SunEdison (Flextronics) 335-watt panels were used for the system. These high-power monocrystalline panels allow a greater amount of power in the same space as less efficient modules that are more widely available. The panels have only recently come to market for general use, though they have been used for some time on systems SunEdison itself installed.
Nine households have their own portions of the system. Almost half of the output goes to the Piros for use in their home and the farm. Others bought into the system in much the same manner that people buy into other community projects. The special Solarize Norwich price was $3.65 per watt, including 25% that goes towards 20 years of operation, maintenance, and insurance. This reflects efficiencies inherent in the EZ-PV system.
The EZ-PV process was developed by Troy McBride and Joel Stettenheim, founders of NST. They are two of four company employees who have doctorates from Dartmouth. The company also benefits from the fact that Dartmouth College is only a short distance away, providing both inspiration and expertise.
Given the level of education and creativity at NST, which led to the EZ-PV system, it should come as no surprise that the company has very active research and development going on. One other project that is in the works is called SunTrap. It is a concentrating solar thermal receiver, using a trough design, developed at Norwich Technologies.
It will be exciting to see what more comes from this Vermont company. Norwich Solar’ website is norwichsolar.com. The phone number is 802-281-3213.
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