Concentration of CO2 in the Atmosphere

Microgrid Secures Power for Rochester-Brandon, VT Mountain Zone

Solar farms and agriculture with cows (or sheep) grazing between solar panels make farming land more productive in community solar farms and microgrid sites with battery storage. They can be valuable to ensure power in rural areas when the grid goes down. (AdobeStock_749830168)

George Harvey

We have had grid outages since the grid began. Fortunately, most outages have not lasted very long, and it has been very unusual to have one that lasted as long as a full day. But it does happen, and the frequency and duration of long outages are getting worse.

The biggest culprit for worsening outages may be climate change. Storms are getting worse. They are getting more powerful and last longer. They dump more rain and snow, and they bring down power lines. They block roads. In some cases, they destroy bridges and tear up the roads themselves.

This has been a concern to Green Mountain Power (GMP) for some time, and its engineers have been designing “resilience zones.” These are areas designed as microgrids to have power when the greater grid is down. They normally have emergency centers in them, where people can take shelter in extended outages. GMP said it intends to put up three such zones every year.

One of the GMP zones is the Rochester Brandon Mountain (RBM) Resilience Zone in Rochester, Vermont. The town was chosen for a resilience zone based on its experiences with extended outages in the past, the worst of which was the one caused by Tropical Storm Irene in 2011. A competitive bid request was put out in 2023, and this was won by Norwich Solar. The microgrid that will be built as the core of the RBM zone will be Norwich Solar’s first microgrid. (Norwich Solar is a subsidiary of Norwich Technologies, a certified B Corporation.)

The design specifications for the RBM zone include a 1,000 kilowatt (kW) solar array with a 2,000-kW battery. The battery will be able to store enough energy to discharge for four hours at full power, so its energy storage is 8,000 kilowatt-hours (kWh). The design was presented to the Vermont Public Utility Commission in 2023, and Norwich Solar announced that it had received its Certificate of Public Good from the commission in January 2024.

Obviously, part of the reason for creating resilience zones is to increase local resilience. However, there are other reasons to have such zones. One is to reduce the cost of electricity. This happens partly because the cost of transmitting electricity on the grid is dependent to a degree on the peak demand during a period. GMP can draw from the zone’s battery during peak demand periods to keep its own peak load down, and this reduces costs for all customers. This also reduces any chance that GMP will have to buy electricity generated at plants powered by fossil fuels, which is more expensive than electricity from renewable resources.

Norwich Solar has started developing the RBM zone, but it still has some designing to do before the actual installation begins. Specific details of the array must be developed, and that includes determining what equipment will be used. So, it is too early to report what solar panels, batteries, charge controllers, and other equipment will be used. We understand that the system will probably have lithium-ion batteries, but even that could conceivably change. On the other hand, we can be sure that construction of the array will begin during the summer or, at latest, the fall.

The site chosen for the array is very interesting on its own account. We often hear about agrivoltaics, so it should be no surprise that the installation would be on a farm, and that it will continue to engage in farming on the same land. What is surprising is the type of farming that will be done. In this case, the land is part of North Hollow Farm, which specializes in 100% grass fed, naturally raised beef. Norwich Solar is designing the array to stand up to cattle grazing beneath the panels, though much of the solar array will be on an old sand pit. The batteries will be on land next to the array.

Kevin Davis, Norwich Solar’s Vice President of Sales, said his company is very excited about this project as the first of possibly many. “We want to do more projects like this. This is where we see the future of solar power and the grid.” He also commented on the way solar projects are developing, “Five years ago, we weren’t actively looking for sites that could host both solar and a battery, but now we are.” The market is changing, and the types of sites that should be built change with it.

Mari McClure, president and CEO of GMP, said, “We are motivated to do all we can to combat climate change and create a Vermont that is sustainable and affordable, but we must move faster. Together with our customers, regulators, our communities, and that Vermont spirit that manages to innovate despite all odds, we have all we need to revolutionize the energy system and ensure a stronger, more affordable Vermont.”

Norwich Solar’s website is norwichsolar.com.

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