Puerto Rico’s Solar Microgrids Beat Blackout

The move sparked an outcry from Puerto Rico’s solar industry and U.S. Representative Nydia Velazquez of New York. Velazquez, who is from Puerto Rico, called the move “shameful” in a post on X, saying the money was designed to serve vulnerable communities on the island.

Solar Energy’s Role in Puerto Rico’s Grid

The ongoing political turmoil and bottlenecked federal funding have prompted the widespread development of solar-plus-storage systems across the island that are privately financed via leases, loans, or Power Purchase Agreements (PPAs). Each month, the island sees around 4,000 solar-plus-battery storage systems come online, Rúa-Jovet says. These installations are connected to the grid but can also operate during blackouts.

At the end of March, LUMA reported over 1.14 gigawatts of grid-connected distributed solar capacity, with an additional 2.34 gigawatt-hours of distributed batteries connected to the grid. Solar power produces over 2 terawatt-hours of electricity each year, which accounts for more than 12.5 percent of Puerto Rico’s total residential electricity consumption annually. The majority of that power is generated from residential solar, and capacity continues to grow as more residents install systems with private financing.

Adjuntas, which has a population of about 18,000, took a more experimental approach. The town’s local environmental nonprofit Casa Pueblo teamed up with researchers from the U.S. Department of Energy’s Oak Ridge National Laboratory in Oak Ridge, Tenn., to develop a way to connect multiple microgrids to exchange power with one another, all without having to be hooked up to Puerto Rico’s grid. The strategy, called grid orchestration, ensures that if power is knocked out on one of the installations, the others aren’t compromised. It’s what kept multiple areas in Adjuntas electrified during April’s island-wide blackout.

During the blackout, Casa Pueblo and the Oak Ridge researchers were completing the testing of the orchestration strategy with three of the five microgrids connected in Adjuntas. These three microgrids are connected to the grid via net metering. The remaining two grids are isolated.

“By decentralizing, it’s creating a more resilient and redundant energy setup,” says Arturo Massol-Deyá, Casa Pueblo’s executive director. “Engineers will say: If you have redundancy, that’s more resilient; that’s better.”

The teams demonstrated trading energy from one microgrid to the other, and vice versa. This kind of transfer enables the system to overcome energy limitations during peak demand times and draw from additional storage at night when the sun is down. Together, the town’s five microgrids provide 228 kilowatts of photovoltaic capacity and an additional 1.2 megawatt-hours of storage, which serve residences and 15 commercial businesses. It’s a small amount of power, but an example of a way for systems to operate independently from the grid.

Oak Ridge National Laboratory researcher Maximiliano Ferrari [left] shares data from the Adjuntas microgrid project with students from the Universidad del Sagrado Corazón [center] and Casa Pueblo’s director, Arturo Massol-Deyá [right].Michelle Estrada

Expanding Microgrid Connections in Adjuntas

Moving forward, Massol-Deyá’s plan is to continue improving and expanding the bottom-up approach to microgrid connections. On April 20, Casa Pueblo launched a lab in Adjuntas called the Community Laboratory for the Energy Transition with the goal of bringing together academics and industry experts to test new microgrid technology as it develops.

The next milestone, Massol-Deyá says, will be successfully connecting microgrids that are not in close geographic proximity. “In Adjuntas, we’re bridging the gap between simulation and theoretical work with a real application,” he says.

As warmer months approach, Puerto Rico is gearing up island-wide for a season of power failures as energy demand will likely exceed Puerto Rico’s generation capacity. This will likely be compounded by a stronger-than-normal Atlantic hurricane season.

Rúa-Jovet maintains that solar and batteries are an easily dispatchable resource that make a “good dent” in resiliency against island-wide power failures. Massol-Deyá agrees and says that even with the government turning toward what he calls an “obsolete” model of fossil fuel power, the Puerto Rican people are embracing solar.

“It’s not top-down: It’s not by LUMA, it’s not by the government. It has been pushed by the people. You have a huge and significant investment by the people on solar,” Massol-Deyá says.