Vermont has turned to thousands of home batteries to replace traditional power plants, creating what Green Mountain Power (GMP) calls a virtual power plant (VPP) that now ranks as the state’s largest single electricity source. Under GMP’s lease program, residents receive two Tesla Powerwall batteries for $55 per month over ten years, and more than 5,500 households have enrolled, gaining backup power during storms while their batteries also serve the grid.
This photo shows a participant in Green Mountain Power’s battery lease program, which supplies residential backup power and grid services.
Illustrates a homeowner’s decision to enroll in the lease program, contributing to the aggregated battery capacity that replaces peaker plants.
The VPP aggregates these home batteries with utility-scale storage, hydroelectric plants and commercial demand‑response resources, using software to dispatch stored power when grid demand peaks. The combined capacity reaches 110 MW—about the output of a small‑to‑average natural‑gas plant—with 53 MW coming directly from residential units. During Vermont’s early July 2026 heat wave, the VPP supplied 90 MW, cutting an estimated $6 million from customers’ peak electricity costs, and GMP reports the VPP saved $11 million for ratepayers over the past year. The program has already enabled the retirement of peaker plants in Vergennes and Rutland.
Visualizes how the aggregated home batteries work with utility-scale storage and hydroelectric resources to meet peak demand, as described in the article.
Looking ahead, GMP plans to offer energy storage to nearly all of its 300,000 customers by 2034 and aims to more than double the VPP’s size, while also exploring vehicle‑to‑grid integration using electric‑vehicle batteries. However, experts caution that such expansion may not be cost‑effective for most consumer EVs today, and the current model depends on continued customer participation despite possible barriers such as enrollment costs and ongoing monthly fees.