The Puerto Rico Energy Bureau (PREB) has approved a motion from Tesla, residential solar and battery installer Sunrun, and residential solar installer SunStrong Management to auto-enroll participants in an emergency capacity resource programme.
The Customer Battery Energy Sharing (CBES) programme was created by the Governing Board of the Puerto Rico Electric Power Authority (PREPA).
In Puerto Rico, the electric generation, transmission, and distribution facilities managed by PREPA are operated privately by Luma Energy, a joint venture between ATCO and Quanta Services, which assumed control of the island’s electricity distribution network in 2020 during the privatisation process that also transferred Genera PR to control its generation. Both PREPA and Luma are overseen by PREB.
According to the order from PREB approving the auto-enrollment, on 23 October 2024, PREB ordered Luma to prepare and file a revised transition period plan (TPP) and propose a permanent CBEA programme and a proposed backup emergency demand response programme to be implemented by June 2025.
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On 19 May 2025, three stakeholders submitted comments regarding the CBES+ proposal: Solar United Neighbors, the Puerto Rico Solar Energy Industries Association DBA Solar and Energy Storage Association of Puerto Rico (SESA), and joint comments from Sunrun, Tesla, and Sunnova, which are jointly referred to as “the Aggregators”.
On 1 April 2026, “the Aggregators” submitted a joint motion to authorise the additional auto-enrollment of batteries in the CBES programme, effectively an aggregated virtual power plant (VPP), for summer 2026.
Kyle Wallace, senior director of public policy at Sunrun, explained on LinkedIn, “Facing major capacity shortfalls last year, PREB turned to the 170,000+ home solar+storage systems on the island to help keep the lights on. The CBES programme existed, but up to that point only had a couple thousand batteries enrolled. “Auto-enrollment” (i.e. opt-out) was proposed as a way to cut through the red tape and enrollment challenges and get this much-needed capacity into the programme as quickly as possible, which PREB approved. That allowed CBES to rapidly expand to 81,000 participants for the 2025 summer. With this latest approval of auto-enrollment, that could increase to over 120,000 participants.”
Wallace wrote further, “The 80MW in CBES only accounts for roughly 20% of the battery capacity for enrolled customers. There is actually *400MW* of 4-hr capacity on those homes, but CBES is striking a balance between the customer’s desire for backup power and supporting the grid given the opt-out enrollment approach. In other words, there is so much potential for this virtual power plant (VPP) to continue to grow!”
The order from PREB states, “In the Joint Motion, the Aggregators state that auto-enrollment of customers in the summer of 2025 was a proven success and assert that continuing auto-enrollment in 2026 will allow CBES to avoid or mitigate larger generation shortfalls, and thus power outages, in the upcoming summer of 2026. The Aggregators state that customer unenrollment rates have been low and that participating customers report high satisfaction with the CBES programme.”
PREB thereby concluded that based on the success of auto-enrolment, “the continued autoenrollment of customers in the CBES programme is appropriate to help further build the emergency capacity available for summer 2026.”
The bureau did clarify, “Paired with the appropriate customer protections explained in the Joint Motion, including providing adequate notice to customers before auto-enrollment, allowing customers to unenroll at any time, and allowing customers to modify their backup reserve level at their discretion, the continuation of auto-enrollment presents an opportunity to increase the size of the CBES resource and thus its ability to mitigate or prevent emergency load shed events.”
Sunrun previously installed batteries that were used for the PowerOn Puerto Rico programme, which supplied backup energy to Puerto Rico’s electric grid during what the company said to be more than 70 energy shortfall events.
Microinverter and home energy storage system supplier Enphase Energy has also expanded support for VPPs in Puerto Rico.
As part of the CBES programme, participants enrolled with three IQ Battery 5Ps were eligible to receive approximately US$1,000 per year beginning in 2025, if the batteries delivered up to 80% of their energy capacity during each demand response event.
A recent analysis from the US Energy Information Administration (EIA) also showed that there is now over 1.4GW of rooftop solar and 2.8GWh of energy storage installed in Puerto Rico.
This makes rooftop solar approximately 20% of Puerto Rico’s capacity mix, and notably, between 2016 and 2025 rooftop solar installations accounted for 81% of the new generating capacity on the island.
