LUMA ordered to complete interconnection study for emergency generation within 8 weeks
The Puerto Rico Energy Bureau (PREB) has ordered LUMA Energy to complete within eight weeks a comprehensive technical study identifying how much temporary power generation can be safely interconnected to Puerto Rico’s electric grid at key substations and generation sites across the island, a move regulators said is necessary to determine how to accommodate the 800 megawatts (MW) of emergency generation contemplated under the government’s grid stabilization plan.
In a resolution and order issued Tuesday, the PREB directed LUMA to evaluate a series of existing transmission and generation interconnection points, determine the maximum amount of generation that can be injected into the grid at each location, identify limiting factors, and propose combinations of sites capable of supporting a net addition of 800 MW of temporary generation. The study must be completed and filed within eight weeks of the order’s notification.
The PREB said the directive stems from continued concerns over Puerto Rico’s generation shortfall and the lack of detailed technical analyses needed to determine where emergency generation can be connected most effectively. Regulators noted that despite years of discussion surrounding emergency power projects, the record does not contain completed system impact studies or facility studies for any of the proposed locations.
According to the resolution, LUMA’s most recent resource adequacy assessment found that Puerto Rico continues to face a structural generation deficit of between 700 MW and 850 MW. LUMA, the private operator of the island’s electric power transmission and distribution system, also reported that peak demand reached approximately 3,234 MW during August 2026 and concluded that the addition of 800 MW of firm generating capacity would reduce the projected loss-of-load expectation during summer months from 7.6 days to 0.1 days, a level the company said is consistent with industry standards.
The PREB criticized the lack of completed interconnection analyses, noting that the only systemwide evaluation for the proposed 800 MW project was a preliminary March 2025 assessment that examined thermal loading but did not include voltage, short-circuit or system stability analyses. Regulators also pointed to documentation showing that previously authorized interconnection studies were never carried out.
Under the order, LUMA must evaluate interconnection opportunities at Aguirre, Costa Sur, San Juan, Palo Seco and Sabana Llana, as well as identify additional power-generation locations elsewhere on the island, including at least Cambalache, Yabucoa and Mayagüez. The review must determine both the amount of generation that can be connected using existing infrastructure and the additional capacity that could become available through grid upgrades, including associated costs and timelines.
The study will examine whether existing bays, transformers, breakers and other interconnection equipment can be repurposed to accommodate temporary generating units without major transmission construction. The PREB said leveraging existing infrastructure is likely the fastest path toward bringing new emergency generation online.
LUMA must also identify transmission constraints, determine the first piece of equipment that limits capacity at each location, estimate interconnection costs, evaluate impacts on existing generation assets and produce an implementation schedule designed to allow temporary generation projects to begin supplying power within six months after contract execution.
In addition, the company is required to provide native simulation files and technical modeling data used to support its conclusions, allowing regulators to independently verify the results.
The PREB warned that the eight-week deadline is intended to produce completed technical findings, not merely a plan for future studies, and cautioned that failing to comply could result in administrative penalties under Puerto Rico energy law.
The order is the latest step in the PREB’s efforts to advance Activity No. 7 of the Priority Plan for Grid Stabilization, which calls for adding 800 MW of temporary emergency generation to strengthen system reliability while longer-term generation and transmission projects are developed.
