Oak Ridge National Laboratory works to build resilience into microgrids in Puerto Rico

Scientists from the Department of Energy’s Oak Ridge National Laboratory (ORNL) have partnered with local organizations to build resilience into independent microgrids powered by renewable energy in Puerto Rico.

Specifically, ORNL is developing a technology that will manage groups of small microgrids as a cluster, enhancing their reliability even when damaged. ORNL engineers Ben Ollis and Max Ferrari lead a team developing a microgrid orchestrator to deploy in the Puerto Rican town of Adjuntas.

A community microgrid project is already being installed in Adjuntas through a partnership between local nonprofit Casa Pueblo and the Honnold Foundation. Honnold is now investing $1.7 million to create two microgrids with solar and battery storage, said Honnold project coordinator Cynthia Arellano. Microgrids are small networks that generally have their own energy supply from nearby renewable sources like wind and solar. If battery storage is added, they can function independently when the broader utility network fails.

The team from ORNL will work with the local groups to create a novel orchestrator tool to manage a cluster of microgrids, so they directly support and communicate with each other. This will make them more resilient during long power outages. If one microgrid loses part of its solar generation, the adjacent microgrid could export power to it.

“I don’t know of a microgrid controller anywhere that can communicate and coordinate with another controller,” Ollis said. “We’re designing an architecture for multi-microgrid controls, so any number of microgrids can operate independently but share information to an orchestrator that will predict when switching, routing, and connecting should happen.”

Initial simulations indicate the microgrids could keep each other running for at least a week, perhaps longer. After Hurricane Maria hit Puerto Rico in 2017, the human toll continued long after the storm passed as residents struggled without electricity for months.

“A lot of people died after the hurricane, and many of the deaths were related to power failures,” Arturo Massol-Deyá, executive director of Casa Pueblo, which promotes fair and sustainable development around Adjuntas, said. “We noticed how many people got sick who were pre-diabetic, or had high blood pressure, or were exposed to unhealthy living conditions and food – preventable conditions. Energy security being interrupted is about quality of life, and there were long-term consequences in the community.” Grassroots support for solar power built steadily as a result.”

The Adjuntas microgrids include solar installations on the roofs of 13 businesses, whose owners agree to provide critical services like medicine, refrigeration, and cell phone charging to residents during major power outages. In return, businesses save money on electricity.

“The orchestrator includes a framework of algorithms that can be expanded and deployed to many microgrids at any site,” Ollis said. “They could provide more reliable electricity to many rural communities at the grid edge. I want to see a future where we have hundreds of microgrids working together to protect critical infrastructure at local, regional, and national levels.”