A utility-scale microgrid is underway in Rutland, Vermont’s largest utility announced Tuesday.
Green Mountain Power (GMP) is constructing a 2-megawatt solar facility on a closed landfill in Rutland, and includes 4 megawatts of battery storage. The company said it expects the project to be completed by December.
The stored energy will be used to shave peak electricity demand at times when solar power is less available – dusk, cloudy afternoons and winter months – and provide emergency backup power for Rutland High School during outages.
GMP says the project, called the Stafford Hill Solar Farm, could theoretically run as a microgrid indefinitely within the lifespan of the equipment. That means the project operates on a closed loop, independent of the region’s electric grid.
The utility designated Rutland City the “Solar Capital of Vermont,” but since then, several larger proposed projects have caused controversy over how solar arrays are sited. But this project’s location on a landfill is a productive use of land because it has not been used for decades, GMP says.
The 9.5-acre landfill closed in the 1990s. The company said the site has settled sufficiently to develop a solar array, and because the landfill has been closed for so long, it no longer emits biomethane, which is often used as another means of energy generation from landfills.
Darren Springer, deputy commissioner of the Department of Public Service, said the project will provide the region with readily available solar power. Typically power grid operators ask utilities to burn fossil fuels to meet high electricity demand on short notice, which, Springer said, is costly and emits greenhouse gases.
The company will hook up the high school to serve as an emergency shelter and will consider expanding to other facilities in the area.
Kristin Carlson, the spokesperson for GMP, said the project is a step toward making communities more resilient to the effects of climate change that can damage electrical infrastructure and create power outages.
GMP has not decided how to account for the renewable energy certificates for the power generated by panels and stored in the batteries. Springer said the generated power could be sold on the market as renewable power, but regulators are still deciding how to account for power coming from the batteries.
Josh Castonguay, of Green Mountain Power, said the lithium ion and lead acid batteries will have to be replaced about every eight to 12 years, depending on how often they are drained and recharged. He said the batteries would be used as little as possible for longevity.
Castonguay said the company is asking the region’s grid operator, ISO New England, to pay for the value battery storage offers for power load management. Having renewable power readily available makes it easier for grid operators to smooth out spikes in electricity demand on short notice.
The company estimates the total project cost for the solar and storage components at about $10 million. GMP received money from the U.S. Department of Energy and the state’s Clean Energy Development Fund to support the project.
South Burlington-based Dynapower will provide the batteries and White River Junction-based commercial and utility solar engineering firm groSolar will provide the panels. State regulators approved the project on July 14.