Green Mountain Power on March 28 told the Vermont House Energy and Digital Infrastructure Committee that it has deployed distributed battery systems with about 4,500 customers and now aggregates roughly 70 megawatts of battery capacity to help shave system peaks, provide backup power and support local reliability projects.

The presentation to the committee by Josh Kastinga, a Green Mountain Power representative, outlined the utility’s residential Energy Storage Service (ESS) lease program, a customer-owned “bring your own device” option, income-qualified installations funded through an ESAP grant program, the Grafton pilot of concentrated home storage in an outage-prone area, and a mobile “Nomad” trailer battery that can be moved to keep towns or commercial customers energized during planned work on transmission lines.

Kastinga said the combined residential battery deployments give GMP “about 70 megawatts of power capacity from these battery storage systems,” and put that number in context against the utility’s 2024 system peak of about 660 megawatts. He told the committee the storage fleet can act as an aggregated resource—sometimes called a virtual power plant—participating in ISO New England markets such as frequency regulation and returning revenue to customers through rates.

The ESS lease provides equipment and installation to a host customer for roughly $55 a month (or an option for a one-time payment), Kastinga said, adding that the host receives household backup power while the utility can use the battery for grid services and peak reduction. “The host customer gets the backup that the storage provides in their home,” Kastinga said. He contrasted that with the retail cost of two rooftop home batteries and installation, which he said could be on the order of $25,000 in a private purchase scenario.

GMP described a bring-your-own-device option under which customers who purchase and install approved batteries can receive an incentive tied to the amount of capacity they make available to the utility for dispatch. Kastinga said most customer systems to date are in the ESS lease program but that the BYOD pathway also works.

Kastinga discussed several pilots and larger distributed projects. The Grafton pilot targeted about 64 customers in an outage-prone pocket and installed roughly 27–30 kilowatt-hour batteries from a variety of vendors to provide local resilience instead of costly distribution rebuilds. GMP has also tested a full distribution microgrid in East Rutland and is deploying additional microgrids in select downtowns, naming Rochester as an example of a location where a microgrid could keep a downtown energized after storm damage.

On mobile storage, Kastinga showed the committee a trailer-mounted Nomad system GMP has used to keep a small town running while the transmission feed was taken out for repairs. He described the unit used in that case as a roughly 1-megawatt, 2-megawatt-hour trailer capable of powering a small town load of a few hundred kilowatts overnight or handling higher short-duration peaks while work is done on the transmission system.

Kastinga told the committee GMP had partnered with state and federal programs to deploy some systems at no cost to income-qualified customers: “The ESAP program actually was funded through ARPA, DOE, and grant, that covered it,” he said, adding that GMP was currently deploying about 100 systems under that program.

Committee members asked about using electric school buses and other vehicles as storage. Kastinga described bidirectional charging pilots with a school-bus operator, where buses are charged midday to soak up solar and then discharged during system peak before being recharged overnight. He also noted early tests of vehicle-to-home and vehicle-to-grid functionality with OEMs and other vendors.

Members pressed on cost and rate effects. A committee member raised a general concern that utility-owned resources could increase rate pressure if customers ultimately pay for assets not fully used; Kastinga answered that GMP evaluates projects on a three-part test—customer benefit for hosts, net value for all customers (positive net present value), and operational value for grid management—and that projects go through regulatory review at the Public Utility Commission.

Kastinga said onsite thermal storage and managed water heaters are other demand-side tools GMP uses or is testing, and that the company is watching new battery chemistries intended for long-duration storage. He also described a “Resilient Neighborhood” pilot in South Burlington—a residential development built all-electric with solar, storage, smart panels and managed charging—where GMP is testing neighborhood-level resource aggregation. He estimated that the project will total about 155 homes when fully built and that roughly 30 units were completed at the time of the hearing.

Throughout the Q&A, GMP staff and committee members emphasized that many potential uses for storage exist—regional capacity and frequency services through ISO New England, local distribution peak management, outage resilience, microgrid operation and vehicle integration—and that the utility is testing a range of technologies, ownership models and funding sources. The presentation highlighted several tradeoffs (installation and installer capacity, site-specific suitability of microgrids versus distributed home batteries, and grant versus rate-funded deployments) that staff said are factors in choosing solutions.

The committee did not take formal action at the hearing. GMP provided materials and said its latest integrated resource plan and related filings are available on its website and under review at the Public Utility Commission and the Department of Public Service.

Kastinga summarized GMP’s view of the role of storage in the evolving grid: “These systems are extremely flexible, and we can— they can be a generator, they can be a load, they can balance the system,” he said, adding that aggregated residential storage is becoming a major, flexible resource for Vermont’s grid.

Ending note: committee members asked GMP to provide additional follow-up information on deployment counts, details on ESAP eligibility and costs, and specifics on microgrid siting and the mobile-unit docking infrastructure; GMP agreed to supply those details after the hearing.