All of these factors combine to ensure that you're spending a small fortune just to keep the lights on. It also ensured that, when Hurricane Maria struck, Puerto Rico was incapable of properly dealing with the resulting fallout. CNN reports that 3 million people are still without electricity and a million have no access to clean running water a month after the natural disaster. There are very reasonable fears that a far larger public-health crisis is looming.

Puerto Rico will need billions to rebuild its crushed infrastructure, and it's reasonable to ask what that is going to look like. Time describes the crisis as a "big opportunity" for renewables, as the island could build a brand new grid to 21st-century standards and embrace green energy. That would harden its infrastructure against future crises, improve quality of life and, hopefully, cut costs to the consumer.

As we explained in our extensive piece on Puerto Rico's energy crisis, the island was already in a pretty bad state. The territory is not connected to the mainland, making it entirely reliant on others for its power needs. It generates power with a series of diesel generators, the fuel for which is shipped in on a regular basis. The costs of fuel are high and the equipment that burns it is, on average, 44 years old. PREPA, which runs the island's power, is $9 billion in debt, and has said that its hardware is "degraded and unsafe."

The aged grid has another problem, which is that upward of 80 percent of its overhead power-transmission lines have been damaged. As FiveThirtyEight explains, these lines often run through high mountain regions where access by road is either poor or nonexistent. Rapidly growing plant matter, which routinely disrupts cabling and other parts of the grid, hasn't helped. As a consequence, it would be an enormous folly to rebuild Puerto Rico's grid in the image of the existing one, not that the island can afford to do so.

PREPA, which runs the island's power, is $9 billion in debt, and has said that its hardware is "degraded and unsafe."

The most obvious solution, and the one that is favored by Puerto Rico's governor, Ricardo Roselló, is to build a series of microgrids. He told Time: "We can start dividing Puerto Rico into different regions, and then start developing microgrids." The official added that while it wouldn't solve the island's power crisis entirely, it would help to get things moving far faster.

And that's essentially what a microgrid is: A way of decentralizing energy generation and localizing it to avoid the issues surrounding transmission over long distances. Rather than an island-wide power grid, each area would have its own generation and storage capacity. Such a system would be ideal for Puerto Rico, because it would negate having to reconstruct transmission lines across dangerous terrain. It would also massively reduce the island's reliance on imported fossil fuels for energy, with the financial and logistical savings therein. In addition, there would be an improved resilience, because there would be fewer obvious points of failure when the next climate-induced disaster strikes.

We've already seen microgrids in action, especially on Ta'ū Island in American Samoa, which Tesla switched to solar power last year. Much like Puerto Rico, the island was previously powered by diesel engines that consumed 300 gallons of fuel per day, costing a small fortune for residents. Tesla replaced the existing infrastructure in favor of a 1.4MW solar array, comprising 5,328 solar panels and 60 Powerpacks. The batteries hold 6MWh of power, enough to run the island for three totally sunless days at a time. In addition, the system can recharge from dry to full in a little under seven hours of sunlight.

Ta'ū is a small test case, with just 600 inhabitants and (relatively) good geography that enabled the solar farm to be installed close by. But Tesla has also built larger solar and battery plants, like its facility on the Hawaiian island of Kauai that handles the island's power needs at night. Kauai has a population of just under 68,000 and so its energy needs are commensurately higher than on Ta'ū. The Kauai facility has a 13MW solar farm connected to a 53MWh Powerpack power storage setup and the early indications are that these systems work.

Tesla has already shipped hundreds of its Powerwall battery systems to the island nation in an attempt to aid the recovery effort. Elon Musk has also been negotiating with Ricardo Roselló in the hope of building a future partnership. The South African billionaire has said that the company can do a similar job as on Kauai and Ta'ū because its systems have no "scalability limit."

The Tesla team has done this for many smaller islands around the world, but there is no scalability limit, so it can be done for Puerto Rico too. Such a decision would be in the hands of the PR govt, PUC, any commercial stakeholders and, most importantly, the people of PR. — Elon Musk (@elonmusk) October 5, 2017

In theory, the system would involve Tesla supplying solar panels and battery-storage panels to parts of the island, broken down by geographic region. Looking at the island, it seems feasible that the company could equip coastal cities like Ponce and San Juan in a similar fashion to its earlier projects. But doing so would theoretically reduce the island's dependency on fossil fuels and cut costs to consumers.

But there are those who believe that Tesla's reach may extend far beyond its grasp when it comes to a national network of microgrids. MIT Technology Review's Jamie Condliffe believes that the company's claims may not stand up to scrutiny and could potentially fail when put into practice. Specifically, he takes issue with the notion that lithium-ion batteries could be used to store and distribute baseload power. Baseload is, essentially, the constant stream of energy required by an electric grid that needs to operate continuously.

Lithium-ion batteries have a limit to the number of times their cells can be charged and discharged before they start to degrade. There's no fixed rule, but Tesla guarantees its (smaller) Powerpack battery for 10 years, and a rule of thumb is that a battery can stand around 5,000 cycles before degrading. In a domestic setting, a battery would likely last around 13 years before becoming unusable. But would such a system work to provide the backbone of a system supplying an island of 3.4 million people?

Then there are the up-front costs, which would be prohibitive for Puerto Rico even if it is likely to recoup the cash over time. A 2015 report by the National Renewable Energy Laboratory believes that in 2014, Puerto Rico's peak demand was 3,685MW. Our back-of-the-envelope math figures that, if each Powerpack has an output of 50kWh, you'd need around 15,000MWh to serve that peak demand.