Puerto Rico Leverages Sunrun's Home Batteries for Extended Grid Stability
Puerto Rico has dramatically bolstered its energy infrastructure through an intensified partnership with Sunrun, the solar and energy storage company. The island's grid recently engaged Sunrun's network of home batteries for an uninterrupted period of 18 days throughout October, highlighting a significant leap in leveraging distributed energy resources for grid stabilization. This collaborative effort has seen the participation in Sunrun's virtual power plant (VPP) double, now encompassing over 60,000 households, thereby establishing a robust and flexible power supply system capable of mitigating the island's persistent electricity challenges.
A virtual power plant functions by connecting a multitude of residential battery storage units, orchestrating their collective discharge to supply power to the grid as a unified entity. Sunrun's VPP in Puerto Rico currently integrates nearly 70,000 batteries, frequently delivering a substantial 45 megawatts of power for four-hour durations. Since April, these batteries have been dispatched more than 60 times, with continuous deployment commencing on October 13 to alleviate strain during an unseasonably warm period. For Puerto Ricans, who contend with some of the highest electricity rates in the United States, averaging 26.36 cents per kilowatt-hour in August compared to the national average of 18.16 cents, according to the US Energy Information Administration (EIA), securing consistent power remains a critical concern. The strategic utilization of existing home battery systems offers an immediate and efficient solution, enabling the grid to access stored energy when demand peaks, circumventing the lengthy process of constructing new power generation facilities.
Sunrun's VPP has experienced exponential growth, expanding from approximately 4,000 customers in 2024 to over 30,000 by 2025, solidifying its position as the largest aggregator within Puerto Rico's Customer Battery Energy Sharing (CBES) program. LUMA, the island's grid operator, activates the CBES program during anticipated periods of high electricity demand or when reserve capacities are low. In response, companies like Sunrun autonomously manage the dispatch of battery power. Participating homeowners receive financial compensation for contributing their stored energy to the grid, while retaining control over the amount reserved for personal backup. Sunrun indicates that most participants share only a fraction of their total battery capacity, with the company generating recurring revenue from the operational management of this extensive network. Data from July reveals that the broader CBES program, with over 90,000 participating customers, has collectively supplied an average of 75 MW during instances of generation deficit.
The imperative for a more expansive virtual power plant in Puerto Rico extends beyond the immediate aftermath of hurricanes. In 2025, Puerto Rican residents experienced an average of 36 hours without power, even excluding major weather events, marking a 19% increase from 2024. This contrasts sharply with mainland US customers, who typically endure only about two hours of outages annually under similar metrics. Major events further compounded the island's power disruptions, adding an additional 23 hours of outages. While an increase in battery storage capacity is undeniably beneficial, the magnitude of the supply deficit remains a critical factor. A regulatory submission in April by participating aggregators indicated that the current program, with its approximately 50 MW of four-hour capacity, was insufficient to avert all rolling blackouts in 2025 when supply gaps exceeded this threshold. Consequently, there is an ongoing drive to enroll more batteries into the program to fortify its ability to address more significant power shortfalls and enhance overall grid resilience.
The strategic deployment and continuous expansion of Sunrun's residential battery network represent a vital step towards energy independence and stability for Puerto Rico. This innovative approach not only empowers individual homeowners by providing financial incentives and reliable backup power but also fundamentally transforms the island's energy landscape, moving it towards a more resilient, distributed, and sustainable model.