Mount Vernon Unitarian Church to Produce Net-Zero Energy
The church will rely on 110 solar panels and thousands of feet of underground geothermal coil
The Mount Vernon Unitarian Church is nearing the completion of a system overhaul to make it a net-zero energy producing facility.
After breaking ground and "retiring" its existing fossil fuel-powered heating and cooling units in December 2010, the Mount Vernon Unitarian Church has installed photovoltaic cells on the structure's roof and geothermal coils underground. The process is expected to be complete this summer. Once finished, the church will be a net-zero energy structure—perhaps the first church in Virginia to hold such a distinction.
Two alternative energy systems are working together to provide electricity for the church, according to Ken Pilkenton, the church's sustainable energy project coordinator. One hundred and ten solar panels—78 on the slant of the roof and 32 on the flat part—make for one of the largest arrays of solar panels in Northern Virginia, Pilkenton said.
Meanwhile, 11,000 feet of coiled pipe containing a fluid are buried in the ground next to the church. Since the fluid is underground, it remains at a low, constant temperature (as opposed to ambient air) and takes less energy to warm to the building's desired temperature.
When the sun shines during the day, Pilkenton said, the panels create a great deal of energy, and the extra power is put back on the grid. At night, the church takes energy off the grid. Eventually, the church will be able to monitor how much and when it takes energy from the grid and gives to the grid.
The church's new power provider is Shenandoah Sustainable Technologies, a commerical clean energy company based out of Harrisonburg.
When the church initially looked into its options, it found high costs for every project. It was SST who suggested the church integrate both solar panels and geothermal pumps.
"SST came and did a site evaluation on us and suggested that the only way it would make economical sense to do it was if we did both at the same time," Pilkenton said.
Replacing ordinary heating and cooling equipment with geothermal technology allows for the limited energy coming from the solar panels to power the heat pumps, Pilkenton said.
"The [solar] panels [alone] would not meet our current electrical requirements for running the building; but, when you put the geothermal heat pumps in, it substantially lowers the draw from the grid. Those systems are very efficient," Pilkenton said. "There's a synergy there of doing both at the same time that allowed us to put the solar in and meet our goal of going to a net-zero facility."
As the church's new power provider, Mount Vernon Unitarian pays fixed monthly payments to SST. The 20-year contract accounts for a small increase for inflation, but otherwise avoids any increase in fossil fuel costs.
"It averages out throughout the year," Pilkenton said. "It also protects us against real large swings and fluctuations in fossil fuels cost."
Currently, the church is paying slightly more per month than usual.
"There was nobody else who could offer what [SST] offered," he said.
According to Pilkenton, the upfront costs for the church were small—only a couple thousand dollars.
The church is on a list to receive a state rebate for alternative energy projects, and SST gets tax credits as a green energy commercial business.
Pilkenton, a member of Mount Vernon Unitarian Church for six years, installed a geothermal heating and cooling system at his house a year ago. For Pilkenton and other members of his church, sustainable energy is part of their religious dogma.
"One of our basic tenets as Unitarian-Universalists is a deep appreciation and respect for the interdependent web that is our world," he said. "Obviously, whatever we can do to lessen reliance on fossil fuels and all the pollution that comes about from the extraction and production of power from these sources really aligns our actions with our beliefs."
The church isn't using its zero energy project for religious proselytizing, Pilkenton said.
"We are, however, looking forward to sharing clean, renewable electricity produced at our place of worship with our neighbors near and far via the power grid."