Puerto Rico’s Energy Future with Microgrids


The complete destruction of the electric grid in Puerto Rico is by far the largest blackout in U.S. history. Hurricane winds mangled the grid’s wires, poles and infrastructure, and even now, four months later, over 40% of the utility’s customers still don’t have reliable power. While the scale of devastation in Puerto Rico is incredible, it is far from the only place in the U.S. with grid problems. In fact, according to power systems engineer Massoud Amin, on "any given day in the U.S. about half a million people are without power for two or more hours" (Gretchen Bakke, The Grid: The Fraying Wires Between Americans and Our Energy Future, 2016). The deterioration of our electric grid through neglect, underfunding and the economic dynamics of investor owned utilities has left the entire U.S. vulnerable to blackouts, although more often caused by squirrels than hurricanes. So what can be done to create reliable power for people? While generating clean energy from the abundant renewable resources around us is clearly part of the solution, it is not enough.

Solar Doesn’t Work During a Blackout, Unless…

When Hurricane Maria hit, almost 10,000 homes in Puerto Rico had solar panels that provided clean power to the houses they were installed on and also could send any extra energy to the electric grid shared with neighbors. These “grid-tied” solar installations are the most common and easiest way to add renewable energy to a home. Most homeowners don’t realize until it is too late, however, that grid-tied solar installations are useless when the grid goes down. So as the storms cleared and the Puerto Rican grid was left devastated, those homes with solar were also without power.

Islanding: Puerto Rico’s Energy Future

In order for a house to be able to continue to have electricity when the grid goes down, it needs to have the ability to “island” itself from the rest of the grid. Islanding occurs when the flow of electricity to and from the grid is cut off, allowing the house to function completely independently as an electricity island. This is usually achieved with a specific switch, called an automatic transfer switch, that is triggered when problems with the grid supply are detected. Once islanded, the house can use its solar panels internally.

Since solar generates variable amounts of electricity and only when the sun is shining, solar alone is not enough during a blackout. Energy storage needs to be paired with the solar to create a reliable solution. Instead of sending the extra energy generated by solar to the grid, some of it will go to charging batteries. When the solar panels are no longer generating, the house can use electricity from the batteries. Through proper sizing and system design, a house can function independent of the grid day in and day out. Many customers using Blue Planet Energy’s Blue Ion energy storage have taken this approach and have even decide to live disconnected from the grid long-term.

Microgrids: Effective Energy Islands for Island Environments

The example of a house with solar panels islanding itself from the grid is sometimes called a “nanogrid” or “microgrid” to describe the fact that it is a tiny grid all by itself. The concept of microgrid can be scaled up with larger solar arrays and battery arrays, to be able to serve the population of entire neighborhoods and villages. This is one of the best options for Puerto Rico to recover from the catastrophic failure of its grid – carve it up into smaller, island-able grids that can interconnect. In most jurisdictions, this process is painfully slow and hindered by various entrenched interests, such as private utility companies that want to prevent any reduction of customer consumption to protect sunk costs, causing actual adoption of this powerful, simple, proven system to never come on line. But in Puerto Rico, the utility, regulators and collaborators in the energy space are pushing forward new regulations to encourage distributed generation, energy storage, and microgrid technologies.

Where The Grid Won’t Go

Despite the promise of regulations favorable to microgrids working with Puerto Rico’s monopoly utility, the sad reality is that there are many areas that won’t see any grid repair anytime soon as the island was already saddled with ballooning debt before the hurricanes. A report produced by industry heavyweights in collaboration with local agencies recommended that while many areas could be served by microgrids, for some regions, the best course of action may be "permanent disconnection from the main PREPA grid." These areas can use microgrid technologies and renewable energies, though they need to be designed for off-grid living. This conclusion was reached even before the decision to privatize Puerto Rico’s utility, PREPA, which opens additional uncertainty about how the financially challenged company would adjust rates. Once privatized and — like so many Investor-Owned Utilities — guaranteed a certain rate of return, there seems to be a high likelihood that electricity rates will go up even higher. While challenging for those people who use the grid electricity, increasing rates will drive further grid defection as people choose to control their own power and stop paying the utility all together.

Rebuilding, With or Without the Grid

Blue Planet Energy has been engaged with partners from solar installers, engineers, nonprofits and community organizers since October 2017. While the situation is still unfolding, we are already supporting the creation of safe, long-lasting and reliable energy systems. Our energy storage systems are being installed in homes and community centers that were once connected to the grid but are now without power, locations with only generators that are expensive to run, and remote regions without clean water or grid electricity as part of water purification systems. We will continue to collaborate in rebuilding Puerto Rico by deploying our leading Blue Ion energy storage system to provide reliable off-grid power to the world.