Famed electric vehicle manufacturer Elon Musk set off a firestorm of speculation last week, when he indicated that he could rebuild the power system of hurricane-ravaged Puerto Rico with solar energy. That seems a bit overly ambitious considering that Musk is best known as co-founder, CEO and strategist behind the Tesla electric vehicle company. However, Musk also serves as chairman for the leading solar installer SolarCity, a subsidiary of Tesla.
In addition, the Tesla EV supply chain revolves around lithium-ion batteries, a form of energy storage that is becoming a standard feature in solar power systems.
Those are important advantages, but can Musk really deliver?
Elon Musk talks scale
To support his solar power promise, Elon Musk referred to SolarCity’s experience in bringing solar arrays equipped with energy storage to other islands. That includes a 1.4 megawatt solar array for the island of of Ta‘u in American Samoa, and a 12 megawatt solar array for the Hawaiian Island of Kaua’i.
Musk claims that “there is no scalability limit” for solar power systems, and on a broad level that’s a fairly accurate claim. For example, India’s new, sprawling Tamil Nadu solar power plant has a 648 megawatt capacity.
However, it’s a pretty long stretch from SolarCity’s island projects to a system that would serve all of Puerto Rico. The American Samoa project serves a population of just 600, and the solar array on Kaua’i provides for only 5 percent of the power for the island’s 33,000 residents.
In contrast, the population of Puerto Rico is just over 3.4 million. Puerto Rico’s tourism industry reported 10 million visitors last year, which also needs to be factored into energy demand if the territory is to regain its economic footing.
Scale is part of the problem — and the solution
Another aspect to the challenge involves the need to rebuild Puerto Rico’s power system along a completely different path. The conventional model of large central power plants and long transmission lines clearly failed the entire island after Hurricane Maria swept through.
According to reports, the island’s power plants were in operational condition following the storm, but that doesn’t help much when the power grid is wiped out.
If Elon Musk is envisioning a series of large solar arrays similar to those in American Samoa and Hawaii, his model could run into similar problems in the event of another catastrophic storm.
One solution would be to break the system into smaller arrays requiring shorter transmission lines and, presumably, shorter repair times.
That basically describes a system of microgrids, and energy infrastructure experts are in fact beginning coalesce around a new grid model that consists of networks of interconnected microgrids. Under normal conditions the microgrids would feed into a wider grid, but in case of emergency each one could disconnect and insulate itself.
Getting down to a more granular level, major public facilities and even individual homes could be equipped with their own rooftop solar arrays and energy storage systems.
That model is already active in Hawaii, where individual electricity customers can now opt in to a “self-supply” system consisting of rooftop solar panels and storage.
What about the next catastrophic storm?
In sum, when Elon Musk talks scalability he’s not necessarily talking about gigantic solar farms. In any case, large-scale solar has limited applicability in Puerto Rico. Mountainous territory, the tourist economy and agriculture are among the factors that create serious obstacles to a significant amount of solar farm development.
On the other end of the scale, the potential for storm damage to buildings limits the application of rooftop solar. Maria left a swath of damaged roofs and totally demolished homes. Before widespread rooftop solar can be considered, buildings need to be hardened against hurricane-force winds, and measures to protect roof-mounted solar panels from flying debris must be developed.
With the damage factor in mind, microgrids using ground-mounted solar arrays could offer the most workable path forward. Other than the potential for washout from storm-related flooding, ground-mounted solar arrays are not as vulnerable as rooftop arrays.
Solar panels are typically engineered to withstand hurricane-force winds and hail, but the potential for damage from flying debris also needs to be factored in for ground-mounted solar. That could be addressed by covering or turn-down systems, though at additional expense.
Portable solar generators may also come into play. The U.S. Defense Department has already invested in transportable solar and storage systems, which could be staged safely in their containers and set up quickly after a storm has passed. As an emergency measure, solar generators could supplement or replace diesel generators, which have proved highly problematic in the aftermath of Maria.
Who’s gonna pay for all this?
Speaking of expense, aside from the engineering challenges involved, the cost of solar power presents an enormous obstacle for Elon Musk’s vision.
The self-supply option may have widespread application in Hawaii and other U.S. states with relatively high per capita income. Puerto Rico, though, is at the lower end of the scale.
Likewise, not many cities, towns and other communities in Puerto Rico have the wherewithal to finance their own microgrids.
Considering that Telsa got off the ground with initial financing from the U.S. Department of Energy, Elon Musk is probably among those anticipating the the federal government will step in.
That’s not too far-fetched. After all, back in 1933 the Tennessee Valley Authority was established with the initial aim of bringing renewable energy — hydropower — to an underdeveloped region of the southern U.S.
On the other hand, considering the Trump Administration’s track record of success on major policy issues so far, any kind of permanent solution for Puerto Rico will probably have to wait for the next presidential election cycle.
The good news is that Elon Musk or not, stakeholders in the fields of energy and economic development are taking a serious look at renewables for a long term solution to Puerto Rico’s power problem.
And, regardless of whether or not the Trump Administration acts, solar powered microgrids are already on their way to Puerto Rico, thanks to Germany’s Sonnen GmbH.
Photo: Northern Puerto Rico as seen from a U.S. Air National Guard WC-130E Hercules on September 29, 2017 by Airman 1st Class Nicholas Dutton.