After the storms, it's microgrid season in the Caribbean

The hurricanes that crashed through the Caribbean in September wrecked people’s lives, homes and other infrastructure.

But the destructive winds of Hurricanes Irma and Maria that exposed vulnerabilities on the islands also demonstrated how renewable energy sources such as solar panels that are connected to batteries and use microgrid technology can bring resilience to islands that have them.

Winds of more than 150 miles per hour downed power lines and damaged some solar farms and other electrical equipment on Puerto Rico and other islands. Seven weeks after Maria made landfall in Puerto Rico, more than half the island was still without electricity, according to the U.S. Energy Department. Nearly two-thirds of utility customers on the island of St. Thomas in the U.S. Virgin Islands were still in the dark, while more than 87 percent of customers on the island of St. Croix and 70 percent of customers on St. John remained without power as of Nov. 9, according to the department.

Some smaller islands emerged from the storms with their solar-power systems intact, thanks to new equipment such as panels and construction techniques that resist hurricane-force winds, smart inverters and batteries that can store several hours’ worth of electricity. Microgrid technologies, such as smart sensors, energy management software and devices that disconnect, or "island," a power generator and battery from the larger grid, create a standalone power supply that keeps operating in the event of a blackout. The technologies, which at one time were prohibitively expensive, are coming down in price, as more utilities and companies use them, utilities say.

Renewable-energy backed microgrids, such as those on Necker and St. Eustatia Islands, also allow energy suppliers to cut their fossil-fuel usage and boost the daily reliability of the electric grid.

On Necker Island in the British Virgin Islands, home to Virgin Group Founder Richard Branson, most power is generated by 300 kilowatts of solar panels, a 900-kilowatt wind turbine, a 500-kilowatt-hour battery, and advanced microgrid controls. Despite heavy damage to buildings and the loss of some of the island’s 800 solar panels, the island’s microgrid survived the storm and power was switched on the day after, according to the Rocky Mountain Institute.

Solar panels and battery storage can be critical to keeping important public resources such as keeping water pumping and wastewater treatment systems operating,  said Christopher Burgess, projects director at the Rocky Mountain Institute's Islands Energy Program. "One of the main human crises on Puerto Rico has been pumping water and getting it to everyone who needs it, due to a lack of electricity. Having solar and storage contribute to critical water pumping and water treatment systems is key because it provides the utility with cheaper forms of generation and can act independently from the larger grid."

Branson has stepped up a campaign to raise financing to help more Caribbean islands install hurricane-resistant solar panels and microgrid technology that can help them reduce their use of petroleum fuel, while also protecting critical power systems against destructive storms.

Branson said he spoke in October with more than 50 representatives of Caribbean governments and utility companies about bringing more renewable power to the region, during a renewable energy conference in Miami.

"We highlighted the importance of renewable energy — solar, wind, geothermal and others — to reduce costs, reduce the harm being done to the environment and increase the resilience of their electric systems to withstand future hurricanes," he wrote in a Nov. 2 statement on the Virgin website. "In the aftermath of Irma and Maria, this message resonated more than ever."

Caribbean island utilities are taking note.

"We are interested in making our system resilient and we have plans of adding more renewable energy in our portfolio," said Rachell Roullet, a spokeswoman at Fortis TCI, the utility that serves Turks and Caicos Islands.

The Dutch island of St. Eustatius, also called Statia, in the northeastern Caribbean, about 35 miles southwest of St. Maarten, is still rebuilding from damage caused by Irma. But the island’s solar farm and microgrid were largely unscathed, said Fred Cuvalay, chief executive of government-owned Statia Utility Company, known as Stuco. It took about 10 days to repair damaged overhead electrical lines and restore power to the island, he said.

"At this time, right now, the whole island is being powered by the solar park and battery system," Cuvalay said, speaking by phone on a recent sunny day in Oranjestad, the capital city.

The 25-square-mile island has almost 4,000 inhabitants, 4 megawatts of solar panels, 5.3 megawatt-hours of battery storage and next-generation smart inverters and software made by SMA that operate the system as an automated microgrid.

The solar panels generate enough electricity during the day to power the island and charge the lithium-ion batteries. When the sun starts setting in the late afternoon, the batteries discharge electricity until about 7 p.m., when the diesel-fueled power plant switches on, Cuvalay said. 

The decision to install solar panels and a microgrid, and cut usage of diesel generators, was part of a financial overhaul of the utility, which previously had been losing $2 million a year, Cuvalay said. The solar panels and microgrid equipment were installed in phases, starting in 2015 and completed last month. The system works better than expected and has made the island’s grid more reliable than it was before, he said, adding that prices have dropped considerably between 2014, when the utility first started on its microgrid project, and this year.

The benefits of the technology and the lower costs are creating more interest among Stuco's peers.

"The word is out, and we’re already getting inquiries from other islands" that want the same type of equipment, he said.