Puerto Rico’s power grid has suffered multiple blows from recent disasters. Hurricane Maria, a devastating and deadly storm, pummeled the island in 2017, causing widespread damage and months of an agonizing blackout for many residents. It was almost a year before the last house was reconnected to the grid.

That storm highlighted the fragile state of Puerto Rico’s grid and prompted calls for change. In 2020 the Federal Emergency Management Agency (FEMA) allocated almost $9.5 billion to the Puerto Rico Electric Power Authority (PREPA), the island’s bankrupt public utility, to repair the grid. By mid-June 2022, $12.8 billion had been earmarked for PREPA in collaboration with LUMA Energy, the company that took over the grid’s transmission and distribution operations in June 2021, to improve the system. But deployment of the funds has been slow, and service remains extremely unreliable. In April a fire at a power plant left the island in the dark. And this month, almost five years to the day after Maria made landfall, Hurricane Fiona unleashed more than 30 inches of rain on some parts of the island, causing floods and mudslides. The damage resulted in yet another island-wide blackout. As of 8 A.M. local time on September 27, more than one week after the storm, about 500,000 of roughly 1.5 million customers were still waiting for power to be restored.

Scientific American spoke with Kaitlyn Bunker, Max Lainfiesta and Michael Liebman—three members of the Islands Energy Program team at the Rocky Mountain Institute, a nonprofit energy research organization—about Puerto Rico’s power grid, the effort to improve grid resilience and the role of renewable energy in that process. The Islands Energy Program collaborates with local partners to facilitate islands’ transitions to clean energy. Lainfiesta and Liebman spoke from San Juan, Puerto Rico, where they were working with local partners on solar-plus-storage microgrid systems. Bunker spoke from Boulder, Colo.

[An edited transcript of the interview follows.]

Before Hurricane Fiona made landfall, how functional was Puerto Rico’s grid?

LAINFIESTA: Hurricane Maria destroyed the grid. After the hurricane, they restored the grid just [enough] so that it worked. But there was never an improvement or preparedness for the next event. That’s why Fiona—which is, incredibly, in five years, the first large storm to hit the island—pretty much left again the whole island without electricity.

For these past five years, the electricity situation on the island is on the news every day. You get into a taxi, and the driver will start talking about electricity. You listen to the radio, you will always be hearing about how bad the electricity system is. Electricity problems are an everyday problem.

What was the situation in Puerto Rico in the days immediately after the latest storm?

LAINFIESTA: [At the time of this interview on September 20] there is no water. Eighty percent of the population is without electricity at this moment. And there’s no information whatsoever as to when the power or the water is going to be restored. It’s pretty chaotic for many people, especially in poor neighborhoods where you have these flooded areas that need a pump to drain the water out, and either the pump has no electricity or the pump is damaged or underwater. It’s a super critical situation in many places. [Editor’s Note: LUMA released an estimated time line of restoration on September 25.]

What specifically caused the power outages?

LAINFIESTA: It’s uncertain. I’ve been trying to figure out why exactly we don’t have power. There is a complete lack of information about it. Scattered information suggests that the generation units are functional, but the transmission and distribution infrastructure is the problem at this point. I saw on the news some crews trying to fix a very critical substation, trying to restore some of the grids. I would like to have an answer to that question, but unfortunately, I still don’t know what the reason is. I’ve been trying to figure it out.

BUNKER: We don’t know a ton of specifics of what’s happening right now in Puerto Rico, why the grid is out. But what we suspect is that it’s in part because of the design of the system, which isn’t specific to Puerto Rico. Most other islands in the Caribbean where we work, as well as larger countries such as the U.S., have a similar design where it’s very centralized. There are a few large generation plants that generate the electricity. Often they’re located far from where people live and use the electricity. There’s a very interconnected system of transmission lines that moves that electricity to the people who are using it. If there are issues with all those lines, which are usually overhead, that knocks out power.

LIEBMAN: LUMA is in charge of transmission and distribution, so they would be responding to that. But they’ve had a lot of challenges. This organization was not involved in Puerto Rico before June 2021. They’ve really struggled to respond to outages and to keep the transmission and distribution lines running. [Editor’s Note: Mario Hurtado, chief regulatory officer of LUMA, told Scientific American that the company inherited a neglected grid. He added that while the grid has continued to underperform since the company took over, LUMA has made important progress.]

Long transmission lines seem suboptimal in natural-disaster-prone areas. What are some possible alternatives?

BUNKER: Part of our approach with our partners in Puerto Rico and in the broader Caribbean is moving to a much more distributed system, where the generation resources are located near the people who are using them. And following an event like this, for example, [those generation sources] could continue to power one building or several buildings in a community to keep the critical electricity needs functioning while the larger grid may be down.

How much progress has there been in this regard since Hurricane Maria?

BUNKER: We have seen some positive movement in terms of renewables being implemented, particularly at the community level and the distributed level, and a focus on the most critical infrastructure: schools, clinics. And there are some great examples of those solar and storage projects that survived this most recent storm—they weren’t damaged, are operating now and providing power locally. That’s wonderful to see. It just hasn’t happened at the scale that we know it needs to happen to impact more and more people across Puerto Rico.

In your view, why are renewables so important for grid resilience?

BUNKER: There is a good solar resource in Puerto Rico. Once it’s installed, you’re using a local resource versus something that has to be imported [such as natural gas or diesel]. That’s a potential failure point—if you’re relying on a resource that has to be imported, and you can't get that resource. If you just put up solar, it has potential to be damaged in a storm. But there are ways to do the design and installation to withstand the stronger storms so that the resource survives the storm and then uses a local resource to generate electricity. [Editor’s Note: Hurtado told Scientific American that LUMA believes renewable energy sources are important for Puerto Rico’s grid. He said the company has been “very aggressive” in connecting residential solar installations and that it is on track “to triple the amount of utility-scale generation in Puerto Rico within a couple of years.”]

Could it help address the transmission challenges, too?

BUNKER: Yes, that’s the other important piece because [renewable energy systems] are quite modular and flexible. You can look at where there’s the most critical infrastructure, the most need for electricity to be consistent, whether there’s a storm or not, and site renewables. They’re on a roof, potentially, on a carport of a parking lot, on the ground as well. But there are just way more options of where to site that. And you can do a smaller project or a bigger project, depending on both the needs and space available. [Editor’s Note: Hurtado told Scientific American that a strong grid—including centralized transmission—will also be essential for meeting current needs and building out renewables. “You need a more sophisticated, stronger, more resilient grid in order to enable renewables. There is no heavily renewable or 100 percent renewable future without investing significantly in the grid,” he said.]

How does equity fit in with the move to renewables and the push for a more reliable and resilient energy system?

LIEBMAN: Puerto Rico, from an economic perspective, has really been struggling. If Puerto Rico were a state, it would have the highest poverty level and the lowest GDP [gross domestic product] per capita in the country. Having these solar-plus-storage and microgrids, it means that, if they’re deployed in the right way, those benefits stay in the communities.

LAINFIESTA: While we are fully supporting the deployment of renewable energy in all sectors, we especially want to make sure that people in low- and middle-income communities can participate in this. Since Maria there has been massive adoption of renewable energy at the household level in Puerto Rico. But of course, this is only for the sectors of the population that can afford it. We want to do renewables—but we need to include equity in the equation.