The ongoing electricity disaster in Puerto Rico in the wake of Hurricane Maria - and on several other Caribbean islands slammed at full force by strong storms - is driving new interest in ways of shifting island power grids toward greater reliance on wind, solar and even, someday, large batteries.
"For the most part, these island grids were completely devastated, and it will be four to six months before most of them can power their islands completely again," said Chris Burgess, director of projects for the Islands Energy Program at the Rocky Mountain Institute.
Adding more renewables, and moving away from centralized power grids to more so-called "microgrids," could lower costs and increase resilience in the face of storms, several energy experts said. And island nations, already at the forefront of pushing for action on climate change, have been moving this way for a while.
Members states of CARICOM, a consortium of Caribbean nations, already have a goal of reaching 47 percent renewable energy by 2027. The storms now only give greater impetus.
"You look at islands like Dominica, Anguilla and the other islands affected by the recent hurricanes, I've spoken to a couple of the utilities, and they say they would prefer to rebuild using distributed generation with storage, and just trying to reduce the amount of transmission lines," said Tom Rogers, a renewable energy expert at Coventry University in Britain who previously was a lecturer in energy at the University of the West Indies in Barbados. "Because that's where their energy systems fail. It's having these overhead cables."
Even in good weather, islands like those in the Caribbean have an energy problem: They've tended to burn fossil fuels, such as diesel or heavy fuel oil, to drive centralized power plants. But being an island without its own fossil energy resources makes shipping in the fuel quite expensive - in turn translating into sky-high electricity bills - to say nothing of the environmental costs incurred by burning it.
"They have energy prices which are some of the highest in the world," Rogers said. "And that has a massive economic impact, especially as a lot of these islands' economic dependence is on tourism, which introduces a high energy demand for their hotels, in particular from air conditioning loads."
And then when a storm comes through, the power lines stretching across the island lead to grid vulnerability.
A different model would be to rely on wind, solar and batteries to store the electricity - with fossil-fuel backup ready to go when needed - and to set up small grids powered by renewables that link to a main grid but that also can be "islanded" from it and do not necessarily go down at the same time.
Wind is very predictable in the Caribbean because of the trade winds, and being located in the tropics makes for a very efficient use of solar panels, Rogers pointed out.
"A PV [photovoltaic] system installed in the tropics will generate over one and a half times more than exactly the same PV system installed in the higher latitudes, say in Washington or Europe," he said.
However, at least until battery storage becomes more widely affordable, islanded grids could not solely be powered by the sun, which is only out during the day. They would instead need to alternate solar with some continuing use fossil fuels to ensure a continual electricity supply. Still, adding renewables would lessen dependence on burning a fuel that has to be continually replaced - which in turn means that it must be continually shipped to the island.
Some lessons here can actually be learned from Alaska. While not an island, it contains many remote communities, and so has been a testing ground for the deployment of hundreds of microgrids - smaller grids that can connect to a larger grid but also can operate independently of one - and for beginning to switch these villages from a strict reliance on burning shipped-in diesel fuel to more renewable resources.
"When we are facing the sort of infrastructure destruction we have seen this hurricane season, it only makes sense to give some pause before reinvesting in the exact same system that proved to vulnerable," Gwen Holdmann, who directs the Alaska Center for Energy and Power at the University of Alaska at Fairbanks, said by email. Referring to Puerto Rico, she continued, "If the system were redesigned around microgrids incorporating local power production, there would still be losses, but the number and duration of outages due to severe weather events would decrease."
However, the Trump administration may have other plans, at least as far as Puerto Rico and the U.S. Virgin Islands go.
For instance, Energy Secretary Rick Perry recently tossed out the idea of the potential for small modular nuclear reactors to be used in situations like the current disaster.
"Wouldn't it make abundant good sense if we had small modular reactors that literally you could put in the back of C-17 [military cargo] aircraft, transport it to an area like Puerto Rico, and push it out the back end, crank it up and plug it in?" Perry said recently, according to Bloomberg BNA.
And not all analyses of island energy changes focus solely on renewables.
A recent report by the energy analytics firm GTM Research found that for islands, the most economical solution right now would actually be swapping in liquefied natural gas for diesel or heavy fuel oil at power plants. But before long, the report said, a combination of liquefied natural gas and solar would be the economic winner. Finally, once battery costs fall far enough, solar combined with energy storage would make the most sense - but the firm doesn't expect that to happen until the late 2020s.
"The potential market for displacing oil with new sources of power supply is very large," said the report by Tom Heggarty, a senior analyst at GTM Research. "We estimate that there are around 3,600 islands around the world where oil products currently provide a large proportion of power supply."
Some islands are already shifting - Jamaica has plans to convert diesel plants to natural gas, and the Hawaiian island of Kauai hosts combined solar and battery storage.
"In Kauai, they actually produce about 90 percent of the island's power during the midday peak just from solar and battery," said Burgess.
Operating a centralized power plant with natural gas, rather than diesel or heavy fuel oil, would save costs but would not necessarily increase resilience when hurricanes strike. You would still have a central plant, distribution stations and a large number of transmission lines to get electricity out across the island.
This is where the idea of combining renewables with microgrids comes in. Microgrids naturally pair with renewables because you can generate electricity at, say, a number of rooftop and community solar installations and then build a local grid based around these resources, often backed by some fossil-fuel-powered generation as well. Individual components of the grid may or may not fare well in a storm, but its fate would not affect other microgrids or the central grid.
"A microgrid's multiple generation sources and ability to isolate itself from the larger network during an outage on the central grid ensures highly reliable power," a recent report from the National Electrical Manufacturers Association found.
It isn't, to be sure, that solar panels are somehow especially resistant to the damage from hurricanes - images from Puerto Rico, for instance, show damaged panels at one major array, the Humacao solar project. However, if some panels go down, that doesn't mean the others won't work any longer, Burgess noted. "It's like New Age Christmas lights: You lose a bulb here and there, but you don't lose all of them."
In the future, "we're going to see microgrids within the islands, but also the large generation being augmented, if not solely replaced, by renewables," said Burgess.