Solar learning (5/14/09)

Local company unveils energy technology at Bellwether School

May 14, 2009

By Tim Simard

Observer staff

With few clouds in the sky, the sun shone brightly down on Williston Friday afternoon — just what the technicians of Earth Turbines Inc. wanted. In the front yard of The Bellwether School on South Brownell Road, employees of the Williston-based alternative energy company oversaw the installation of one its newest creations.


    Observer photo by Tim Simard
Chris Tall, a special projects engineer with Earth Turbines, explains the motorized design of the company’s AllSun Tracker. 

Standing just over 14 feet high, Earth Turbine’s AllSun Tracker — an electric grid-connected solar panel system — is now a dominant feature at the small private school. Unlike other solar panel systems, the AllSun Tracker stands on its own and uses the latest technology to harness and maximize the sun’s energy potential, said Caleb Elder, Earth Turbine’s customer support specialist.

“It’s a completely unique design, especially here in Vermont,” Elder said.

Earth Turbines, a sister company of NRG Systems Inc. in Hinesburg, has been busily creating new and exclusive energy systems at its headquarters on Harvest Lane for the past year. After six months of testing, Elder said the AllSun Tracker is now ready for the home and commercial market. Earth Turbines jumped at the chance to work with The Bellwether School to install its first tracker, Elder said.

“It’s perfect — they’re in our own backyard,” he added.

Officials at The Bellwether School said the new solar device is a perfect fit with the school’s holistic education philosophy. Bellwether’s co-director, Stacey Weinberger, said the tracker would become an integral part of the school’s environmental curriculum, a focal point of the school’s education.

“It’s been a part of Bellwether’s history since 1995 when we were founded,” Weinberger said.

The school, which teaches 41 elementary and middle school students in multi-age classroom settings, officially unveiled the tracker during its annual Spring Festival on Saturday. But Friday’s quick installation gave students their first look at the device. Parent Jean Reinsborough said teachers and students are thrilled with its addition and are already talking about the many ways it can be used in education.

“They’ve got all kinds of ideas on how to make it relevant in math (and) science,” Reinsborough said.

Elder said the AllSun Tracker is more efficient and captures more energy than most solar panel systems. Most solar panels remain in stationary positions on roofs or other structures, he said. The AllSun Tracker follows the sun’s journey across the sky each day, maximizing the solar energy captured. Elder estimates the system produces 35 percent to 45 percent more energy than the average fixed panel.

The tracker not only moves east to west following the sun, but also up and down to capture the sun’s energy at different heights of the horizon. Wireless GPS satellite technology allows the tracker to move on its own.

“It basically lines itself up with the sun,” Elder said.

The Bellwether School decided to install Earth Turbine’s smallest model, which has 12 individual solar panels attached to one platform. The model generates 3,420 kilowatt hours per year on average, Elder said. He estimated the tracker would produce about 20 percent of the energy the school uses per year, helping to reduce overall energy costs in the long term.

Earth Turbines also has two larger AllSun Trackers. One generates more than 4,300 kilowatt hours per year, and the other generates nearly 6,000 kilowatt hours annually.

Bellwether’s tracker is hooked directly to the electricity grid, with all energy produced recorded through a metering system. If the tracker produces more energy in a day than the school uses, then energy credits can be accumulated with Green Mountain Power.

While the tracker does not come cheap, Earth Turbines has found a way to make it more affordable. For instance, the school is taking part in the company’s lease program. After an upfront cost of $1,000, the school will pay 14 cents per kilowatt hour. That would break down to about $57 per month, though Green Mountain Power’s “Solar GMP” program will further reduce costs for the school.

The school signed a five-year lease, after which it can extend the lease or buy the tracker outright. Weinberger said the flexibility and affordability of the lease program made it possible for the school to install the system.

“We would not have been able to do this without the lease program,” Weinberger said. “It’s a win-win for everyone.”

It’s also a win for students, she said. Weinberger said having an alternative energy system at the school would go a long way in teaching children the importance of energy conservation.

“It’s saying that we can do something about the environment, we can make a difference,” she said.