Sunrun’s home batteries in Puerto Rico were dispatched for 18 consecutive days starting October 13, during an unusually hot spell, and the company says its network now covers more than 60,000 customers and nearly 70,000 batteries. The aggregation reliably delivers 45 megawatts of dispatchable power for four hours at a time. Puerto Rico’s grid operator, LUMA, calls on that stored energy when it expects demand or reserve needs to exceed available generation.
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Sunrun is the largest aggregator in the island’s Customer Battery Energy Sharing program, known as CBES.
Forty-five megawatts for four hours, dispatched more than 60 times since April
In a November 3 release, Sunrun said participation doubled to more than 60,000 customers and that it has dispatched the plant more than 60 times since April 2026 to cover severe energy shortfalls. Enrollment rose from about 4,000 customers in 2024 to more than 30,000 in 2025. Customers choose how much energy to share, with most contributing a small portion of their battery capacity and keeping the rest for home backup. Participants are paid for the energy they share, and Sunrun earns recurring revenue from operating the network. The company says the plant was dispatched on a daily basis from October 13 and has been called on more than 60 times since April, a cadence that turns what began as an emergency tool into routine grid support.
Chief executive Mary Powell called the Puerto Rico experience “a vital blueprint for the U.S. mainland,” where severe weather and AI data center growth are driving demand for new energy solutions. The release also quotes LUMA as saying that home-battery energy helped it overcome generation shortfalls and avoid previously announced load shedding in June and July.
Auto-enrollment and the limits of 50 megawatts
Electrek’s Michelle Lewis, who reported the figures on November 4, noted that LUMA said in July that more than 90,000 CBES participants across all aggregators helped supply an average of 75 megawatts during generation shortfalls. Sunrun’s network is therefore a large share of the program rather than the whole of it.
The program’s ceiling is documented in a March 31 filing by Sunrun, SunStrong Management and Tesla with the Puerto Rico Energy Bureau. The filing says CBES grew to more than 81,000 customers in 2025 through auto-enrollment and reached about 50 megawatts across a four-hour dispatch, yet manual load shedding still occurred on some days because generation shortfalls exceeded that capacity. The aggregators asked to keep 2025 enrollees in through fiscal 2028 and to enroll more batteries during 2026, which they estimated could add up to about 30 megawatts of four-hour capacity.
The Energy Bureau agreed. As reported by Energy-Storage.news, it approved the aggregators’ motion to continue auto-enrollment for summer 2026, citing customer protections that include advance notice, the right to unenroll at any time and the ability to adjust backup reserve levels. Kyle Wallace, Sunrun’s senior director of public policy, said the enrolled homes hold about 400 megawatts of four-hour capacity, against the roughly 80 megawatts that CBES enrollment covers.
Electrek also supplied the plain-language definition of what Sunrun runs: a virtual power plant that, in its words, “connects batteries across thousands of properties and coordinates them to supply power together.” The company’s own growth curve is steep, with about 4,000 customers in 2024, more than 30,000 in 2025 and above 60,000 now, and the Energy-Storage.news account puts more than 170,000 home solar-plus-storage systems on the island, so the enrolled pool still leaves large numbers of batteries on the table.
The same report gives the wider resource picture. Puerto Rico has more than 1.4 gigawatts of rooftop solar and 2.8 gigawatt-hours of storage, about 20 percent of the capacity mix, and rooftop solar made up 81 percent of new generating capacity from 2016 through 2025. Under the approval, CBES enrollment could exceed 120,000 participants, up from about 81,000 in summer 2025, and participants with three IQ Battery 5P units could earn about $1,000 a year if they deliver up to 80 percent of capacity during events.
Outage hours and electricity prices behind the dispatches
The Energy Information Administration put numbers on the reliability problem in an August 10 analysis, noting that no major hurricane directly hit the island in 2025, and that heavy rain and flooding in April and May plus Hurricane Erin’s tropical-storm-force winds drove the major-event outages. Puerto Rican customers averaged about 36 hours of interruptions in 2025 outside major events, up 19 percent from 2024, with major events adding about 23 more hours. Mainland customers typically see about two hours a year without major events. Interruption frequency rose 13 percent from 2024 to 2025 and has doubled since 2021.
Electrek, citing federal data, put residential electricity on the island at 26.36 cents per kilowatt-hour in August 2026, against an American average of 18.16 cents. Higher prices and longer outages are the backdrop for a program that pays homeowners to share stored power. What remains unclear is whether storage on the scale of CBES can grow fast enough, since the aggregators’ own filing conceded that dispatches could not cover every 2025 shortfall, and the release does not quantify which outages the 18 days of dispatch headed off.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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