Enel X and power equipment and management company Eaton will partner on a solar-storage microgrid in Puerto Rico, one of the largest yet built on an island struggling to restructure its hurricane-battered power grid. 

The microgrid, Enel X’s first such project in Puerto Rico, will provide backup power at Eaton's circuit breaker factory in the coastal city of Arecibo. It will center on a 5-megawatt solar array and 1.1 megawatt/2.2 megawatt-hours of battery storage. 

Beyond helping back up Eaton's facility in case of outages or storms, the microgrid will also feed power back to the grid. The companies said the project is designed to reduce “demand on local energy infrastructure,” a common concern as the U.S. territory reimagines an electricity system that was severely damaged by Hurricane Maria in 2017. 

“If you think about the three things underlying projects like this, number one is the resiliency factor,” said Surya Panditi, CEO at Enel X North America, who also cited the ability for distributed resources to participate in local markets and economic viability.

Enel X, which grew out of energy giant Enel’s acquisition of EnerNOC, Demand Energy and eMotorWerks, will build the system along with an engineering, procurement and construction provider and then maintain ownership of it. Eaton will help engineer the project and contribute electrical equipment, including its microgrid controller.

The project is a “postcard from the future” for islands and other centralized grid systems transitioning toward more distributed resources, said Isaac Maze-Rothstein, an analyst at Wood Mackenzie who focuses on microgrids. 

In a resource plan laid out this summer, Puerto Rico’s energy bureau ordered the Puerto Rico Electric Power Authority (PREPA)  to acquire at least 3.5 gigawatts of new solar and more than 1.3 gigawatts of storage in the coming five years. Legislation passed last year requires the island to reach 100 percent renewable electricity standard by midcentury.

Since Hurricane Maria significantly disrupted the island’s electricity system, policymakers, clean-energy advocates and energy companies have been grappling with what the future system will look like.

Resiliency, clean energy on an island grid

Microgrids, as well as solar and storage, have grown in popularity in Puerto Rico since Hurricanes Maria and Irma hit in 2017. Significant earthquakes also roiled the island in 2020, causing power outages.

Most of Puerto Rico’s existing microgrid systems are relatively small, said Maze-Rothstein, with just a few microgrids with capacities greater than 5 megawatts now installed. Enel and Eaton’s system is comparatively large. In addition to its 5 megawatts of solar, it will integrate with Eaton’s existing onsite power generation. The Arecibo plant currently has five diesel backup generators totaling 8 megawatts in capacity, according to Eaton. 

The largest microgrid system installed in Puerto Rico is 20 megawatts and is sited at a pharmaceutical facility, according to tracking from WoodMac. Once a combined-heat-and-power project, it now relies on natural gas. Developers Sonnedix and Yarotek own the island’s largest solar-plus-storage microgrid system: 16 megawatts of solar that came online in 2015, prior to the island’s latest burst of renewables development.  

Projects like the one from Enel X and Eaton show a “change in mindset” toward solar and storage, said Maze-Rothstein, as large-scale electricity users on the island come to terms with Puerto Rico’s plans for a fully renewable future.

“If we were talking about microgrids in Puerto Rico five years ago, almost all of them would have been nearly exclusively diesel, and maybe some were considering [liquefied natural gas],” said Maze-Rothstein.

However, some customers are still keeping an eye on natural gas as a cheaper option than diesel, he said. Though the island’s energy bureau ordered PREPA to pursue significant renewables and storage build-out in the short term, clean-energy advocates worry that the selection of Luma Energy in June to manage the island’s grid could jeopardize that path. Luma has ties to several natural-gas businesses. New Fortress Energy also recently opened a liquefied natural gas import terminal in Puerto Rico that supplies natural gas to PREPA.  

Eaton, which operates four facilities on the island, has committed to carbon-neutrality by 2030. Enel X told Greentech Media it plans to consider additional projects in Puerto Rico.

This story has been updated.