Green Mountain Power, Vermont's largest utility serving over 75% of the state, has assembled what may be the largest home battery programme in the United States. More than 5,500 households now lease two batteries each at $55/month over 10 years, and the aggregated system — a virtual power plant — has become the state's single biggest power source. GMP's peaker plants, once essential for meeting peak demand, are being decommissioned as the distributed network replaces them. The programme's appeal to customers is brutally practical: resilience. Vermont's rural geography and harsh winters make prolonged outages dangerous. Participants report zero power losses since installation, even when neighbours on the same street go dark. One customer powered her home for five days during an outage using only her Ford F-150 Lightning's battery. GMP has set a goal of eliminating all power outages by 2030, combining the battery programme with measures like undergrounding power lines. The economics are straightforward. A $55/month lease over 10 years totals $6,600 — roughly half the $12,000 cost of the gas generator many Vermonters were buying instead. GMP's virtual power plant saved customers $11 million last year. The US Department of Energy estimates virtual power plants could save the country over $10 billion annually by 2030. The model works because utilities pay households to provide grid services that traditionally went to large fossil fuel operators. The programme surged after state regulators lifted a cap on enrolment in 2023, with over 2,500 new participants since. Around 50% of battery households also have rooftop solar, creating genuine two-way energy flows. GMP plans to offer storage to all nearly 300,000 customers and aims to more than double its virtual power plant capacity by 2034. Vehicle-to-grid integration — tapping EV batteries as distributed storage — is the next frontier, though experts caution it's not yet cost-effective for most consumer EVs. The structural barrier is national, not local. Most US utilities operate under a financial incentive structure that rewards building new infrastructure over managing demand flexibility. As former DOE official Jen Downing puts it: "Utilities don't have much incentive to harness demand flexibility because they make more money if they just build stuff." Vermont's model works partly because GMP's regulatory environment allows it. States like Massachusetts, Illinois, and New Jersey are now pushing similar procurement mandates. Virtual power plants don't generate electricity — they orchestrate existing distributed resources via software to reduce peak demand and improve grid stability. The concept has existed for decades but is scaling now because rooftop solar, home batteries, and EV batteries have reached sufficient density. Germany and China are building similar systems. The core insight is that thousands of coordinated small batteries can replace a centralized gas plant, at lower cost, with better resilience. The 20-year implication is significant: if this model scales beyond Vermont, the traditional utility business model — build centralised plants, charge ratepayers for capital expenditure — faces structural disruption. The question is whether incumbent utilities and their regulators will allow it.
