Demand for Solar-Storage Systems Explodes in Puerto Rico

A solar engineer describes his efforts to help residents produce and monitor their own power—but the grid’s instabilities are still making it hard to get ahead

Photograph of Gabriel Rivera at a solar installation in Puerto Rico.
Photo: Gabriel Rivera
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When I first met Gabriel Rivera last year in San Juan, Puerto Rico, the engineer was driving around with solar panels in his car. Hurricane Maria had ravaged the island on 20 September 2017 and knocked out the entire grid. Rivera was building household emergency kits, consisting of a solar panel hooked to a battery, to help people power their vital medical equipment. His own apartment was damaged in the storm, so when we spoke, he was in the process of moving the panels to a safer spot.

State-run Puerto Rico Electric Power Authority (PREPA) and the federal government spent 11 months and billions of dollars restoring electricity across the U.S. territory, yet the grid remains just as vulnerable to hurricanes and brownouts. Since Maria, solar-plus-storage systems have proliferated in Puerto Rico as residents and companies seek off-grid solutions, and thousands more projects are in the works. On the grid, utility-scale solar installations make up just 2.1 percent of Puerto Rico’s total generating capacity.

I caught up with Rivera this month to learn how life has changed in the past year. Our conversation is edited and condensed for clarity.

IEEE Spectrum: In the wake of Hurricane Maria, have you noticed a shift in people’s attitudes toward solar projects?

Gabriel Rivera: The solar market in Puerto Rico just completely changed after the hurricane. At my business Verdifica, we used to mostly do design and consulting for grid-tied solar installations, with net metering. I would say 95 percent of the projects had no batteries. After the hurricane, 100 percent of the projects we’ve done include batteries, even though it almost doubles project costs.

Our customers lost confidence in solar without batteries, because many people with grid-tied systems didn’t have a way to use their solar panels during the extended outage. Now, everyone has requested to have at least a bit of power backup.

Our systems usually run between [US] $20,000 to $30,000, for 3 to 5 kilowatts of photovoltaic (PV) capacity, with around 10 kilowatt-hours of usable storage. Everybody is going for self-consumption programming, so that they buy as little electricity as possible from the grid. The key is to get PREPA out of your bill.

The only problem is that really few people have money to actually get solar.

Spectrum: Are you still building and donating small solar kits for people with medical needs?

Rivera: We did about 40 to 50 projects across the island, and people still have those in their homes, but we don’t do any more urgent installations right now, because most people have power again. But some family members and neighbors of the patients were like, “I want something like this, too.” So we’re actually manufacturing a product that is low-budget—around $4,000—to run your lights, refrigerator, and so on, and we’re working with two foundations.

Some clients are opting for solar only because they need the power quality. There’s so much intermittency in the grid that it damages their appliances, and they’re tired of having their TV, modem, and refrigerator gone because of brownouts. They have opted to use an off-grid, isolated, and dedicated PV system just for that equipment. They don’t want to rely on the grid any more.

It’s a laboratory here; I’m so busy doing so many different requests. There are a lot of people who live in multilevel buildings who don’t have a way to put solar on the roofs, but they do need some type of backup as well, at least for their refrigerators and lights so they can survive an extended outage. So we’re installing systems with an inverter charger and batteries, just without the solar component.

Spectrum: As PREPA struggled to restore power, Puerto Rico adopted measures to allow more electricity installations and microgrid projects. How did that affect your business?

Rivera: PREPA changed their way of classifying PV projects, allowing us to do the projects first and then ask for permission. Now, for projects that are less than 10-kilowatt PV, it’s fast-tracked. You don’t need an inspection, whereas before you had to do this for every single project. Because of that, a lot of smaller projects are going up.

Solar is so competitive right now that prices have gone down. I can even say that electrical materials are in more stores now than before the hurricane, like conduits, breakers, and distribution equipment. But it’s also very chaotic. It’s regulated, but it’s kind of an open market for anybody to do residential projects.

In my opinion as an engineer, there’s nothing here that I can call a microgrid yet. The word “microgrid” is being abused right now. People just think it’s an island, but a microgrid has other points of interconnectivity. If you have a set of distributed generators, that’s what you have: distributed generators—a microgrid has to share energy. Right now, we have net metering, so we are sharing energy without having to call that a microgrid. But the energy security of an actual microgrid is something else.

Spectrum: What other recent challenges have you experienced with solar installations?

Rivera: The grid’s power quality is still not good. At some installations, we’re having to slightly broaden the voltage and frequency ranges in order for the equipment to recognize the grid service as the grid service, and not classify it as dirty power, as per IEEE 1547 (the standard for interconnection and interoperability of distributed energy resources with associated electric power systems interfaces).

One of the problems with this is that it puts some of the battery-based systems to “off-grid” mode for long times, often leading to unexpected battery drain. System owners find it hard to understand why their solar system is behaving this way, while their neighbors seem to have utility power. And PREPA seems to have way too many problems for us to realistically expect the power quality to be restored to acceptable levels. We’re still working with a lot of uncertainty, and my fear is, how long will this be going on?

Spectrum: What steps are you taking to ensure these installations can withstand future hurricanes?

Rivera: I don’t know if I have seen a single installation that can truly be labeled as “hurricane proof.” The challenge is not only about withstanding the winds, but also about protecting solar panels from loose objects that have become high-speed projectiles. Very small systems, with about six PV modules or less, are easier to simply remove and store during a storm of this kind. The more common residential system sizes here, of about 3 to 10 kW of PV—about 10 to 30 modules—can be unpractical to remove and reinstall.

We’re actually working on a project with local architect Eduardo Rolón Bonilla, in which a 5-kW array of PV modules will be installed on a concrete roof with parapets, in such a way that storm shutters can be integrated to cover and protect against these hazards. The majority of roofs here are flat concrete, and pretty much all the PV systems are fixed-tilt type—no sun tracking. To have some degree of protection against flood damage, good old-fashioned concrete pads are often used to raise floor-mounted batteries or energy storage systems above ground level.

In general, we also like to keep electrical equipment indoors when possible, even when the enclosures are rated for outdoors. Outside temperatures and direct sunlight exposure have shown to be detrimental for this equipment, and rust is also a special reality to consider here. These are some of our basic rules of thumb.

Editor’s note: This story was updated on 28 September.

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