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September 9, 2019 • Filtrine's solar array is Keene's largest. It produces enough power to cover Filtrine's total energy needs and put energy back into the grid.

Filtrine Solar Array 2019 Installation -

Filtrine Solar Array 2019 Installation

Photo Courtesy of ReVision Energy

In 2019, Filtrine, a Keene-based manufacturer of water chilling and filtering system, took the next big step towards carbon neutrality by installing 2,225 solar panels on its 100,000 square foot roof. Rated at 793 kW (DC), the solar array installed by ReVision Energy is the largest in Keene and possibly the largest rooftop installation in the region. The array produces approximately 900 megawatt-hours per year, more than covering Filtrine’s needs and even putting some energy back into the grid.

Filtrine’s President, Peter D. Hansel, commented on the decision to make this investment. “This idea has been percolating for ten years," he said. In 2009, Filtrine refurbished its old roof and looked into adding solar panels at that time, but the cost was high and they were concerned that the roof couldn’t handle the additional weight. They did install some solar hot water panels to heat water for their test room, and those are still working well today. Five years later, they installed 120 PV solar panels (36 kW DC) along the north perimeter of their roof where there was plenty of structural support. 

In 2014, Filtrine contracted with students from Antioch New England to evaluate their environmental footprint. This gave the company a baseline from which to measure progress and inform decision making. In addition to energy conservation measures like improving insulation and installing LED lighting and energy efficient machinery, Filtrine contracted with Froling Energy of Peterborough in 2017 to install a 1 million BTU wood chip boiler for heating.  This reduced reliance on oil by 90 percent.

As solar panel technology improved and costs came down, Filtrine decided to take another look at installing a larger solar array on its roof in early 2019. ReVision hired a structural engineer and concluded that it could work. The  system should pay off its $1.5 million investment in about 5 years, after which time Filtrine’s electricity will be delivered for free, compliments of the sun.

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