Renewable energy technologies are at the centre of a US$17.6-billion, 10-year “build back better” strategy being put forward for Puerto Rico’s shattered electricity grid, aimed at restoring services lost to Hurricane Maria while increasing the system’s overall resilience.

“The magnitude of devastation to the Puerto Rico electric power system presents an unprecedented opportunity to rebuild and transform the system to one that is hardened, smarter, more efficient, cleaner, and less dependent on fossil fuel imports,” stated the report of the Puerto Rico Energy Resiliency Working Group, a collaboration between the New York Power Authority (NYPA), the Puerto Rico Electric Power Authority (PREPA), electricity industry organizations, and the U.S. Department of Energy.

“This system will deliver increased renewable energy resources, such as wind and solar; incorporate new distributed energy resource technologies, such as energy storage and microgrids; reduce dependency on fossil fuels; and enable energy to become abundant, affordable, and sustainable.”

The report aims to prepare Puerto Rico’s grid, much of which was built more than a half-century ago, to withstand an “upper Category 4 disaster,” Greentech Media reports. “Many of the recommendations echo what has already been suggested for the island—including undergrounding specific lines, instituting modern grid control systems and automated distribution systems, investing in distributed resources, and replacing infrastructure with hardier materials.”

Along with extensive repairs and upgrades to Puerto Rico’s main grid, the report recommends “concentrating onsite solar arrays, storage, and microgrids at critical infrastructure sites: 26 hospitals, 20 police departments and 20 fire stations, along with 75 microgrids at emergency shelters, and at 10% of wastewater and water treatment facilities,” Greentech notes. “Because 470,000 homes need repair or reconstruction, workers could incorporate solar there, too.”

Greentech notes that New York already has 450 utility workers in Puerto Rico under a mutual aid agreement, mostly in Old San Juan. After the state’s own experience with Hurricane Sandy in 2012, “we are well prepared and uniquely qualified to help them restore power,” said NYPA CEO Gil Quiniones. “This is what we do every year—there’s always a storm.” 

At the same time, “Puerto Rico’s uniquely devastated grid, topography, and infrastructure have all presented New York crews with new challenges,” Greentech notes, prompting Consolidated Edison incident manager Orville Cocking to call the work “humbling”. While much of the repair activity in the two jurisdictions is similar, there are also big differences.

“The overhead, radial distribution system looked familiar to New York crews, as did the equipment and the voltage,” Greentech states. But “in Old San Juan, for instance, the archeological significance of the colonial-era district means poles can’t be dug into the ground. Instead, they’re placed high up on rooftops, which in some cases had been made unstable by the storm.” Quinones acknowledged that “we would never see anything like that in New York.”

The conditions on the ground prompted Virginia-based energy company AES to propose redesigning Puerto Rico’s grid into a “network of regional mini-grids powered by up to 10,000 MW of solar and 2,500 MW of battery storage,” Microgrid Knowledge reports.

“The mini-grids would spare the island the kind of cascading outages that occurred during Hurricane Maria,” when “damage to long-distance transmission lines cut power delivery from generators on one side of the island to populated regions on the other side,” MK recalls. “In contrast, the mini-grids would be situated close to those they serve, so would not be subject to the vulnerability of transmission lines.”

Based on 15 years’ experience on the island, the company calculated that local distribution lines could deliver 70% of the system’s load. “Because each mini-grid uses solar, it spares the island from the need to import fuel, which became scarce following the storm,” MK notes. And at a cost of $40 to $50 per megawatt for solar and $55 to $65 for storage, “the upfront capital cost for the mini-grid project would be less than what it costs to fuel Puerto Rico’s existing generation over 10 years.”

Meanwhile, an analysis by the New York Times earlier this month showed that 1,052 Puerto Ricans may have died as a result of Hurricane Maria, massively more than the official count of 64. “The Times’s analysis found that in the 42 days after Hurricane Maria made landfall on September 20 as a Category 4 storm, 1,052 more people than usual died across the island,” based on mortality data for the same days in 2015 and 2016, the paper reported.