Hurricane Florence crippled electricity and coal -- solar and wind were back the next day

Nearly two weeks after Hurricane Florence swamped North and South Carolina, thousands of residents who get power from coal-fired utilities remain without electricity. 

Yet solar installations, which provide less than 5 percent of North Carolina's energy, were up and running the day after the storm, according to electricity news outlet GTM. And while half of Duke Energy's customers were without power at some point, according to CleanTechnica, the utility's solar farms sustained no damage.

Traditional energy providers have fared less well. A dam breach at the L.V. Sutton Power Station, a retired coal-fired power plant near Wilmington, North Carolina, has sent coal ash flowing into a nearby river. Another plant near Goldsboro has three flooded ash basins, according to the Associated Press, while in South Carolina, floodwaters are reportedly threatening pits that contain ash, an industrial waste from burning coal. 

The lesson, according to environmentalists: Utilities' vulnerability to major storms underscores the urgency of shifting to energy that it is not only clean and renewable, but also more resilient.

The push comes in response to the Trump administration's move last year to prop up coal and nuclear plants under the argument that because they can store their fuel on-site, they can provide constant power and thus serve national security purposes. But Florence's shutting down of one nuclear plant and breaches of old coal ash ponds show that no source of power is immune, environmentalists say.  

The vast majority of power failures that happen during storms occur because transmission lines or substations get damaged -- not because fuel runs out. Above-ground lines, vulnerable to wind, rain and hail, can even fail during a thunderstorm, let alone a hurricane.

Redistribution of power

A 2017 study by Rhodium Group, which examined all power outages between 2012 and 2016, found that essentially none were due to a lack of fuel to generate power. This scenario is repeating itself in Florence's aftermath, energy analysts said.  

The extreme flooding from Florence was another reason that power took time to come back, despite facilities like wind and solar farms remaining unscathed.

"No electric company is going to power their lines when they're underwater," said Chris Burgess, projects director at the Rocky Mountain Institute. "It's dangerous because you have transformers underwater, people's meters underwater, underground switchgear. The utility just needs time for the water to go down," he said.

To Burgess, Florence -- and last year's hurricanes, in particular Maria -- make the case for "distributed power," such as rooftop solar panels.

In Puerto Rico, although Maria took out the power grid, locations that had their own solar installations, including a farm and a community center, were able to stay open.

"Solar is resilient -- there are a ton of cases where, as long as the roof stays attached, the solar array stays attached as well. That's the real takeaway," he said. Given its elevation, a rooftop solar installation has a better chance of survival than power lines or transformers closer to the ground.

It's precisely after a storm that customer interest in solar spikes, several energy companies that operate in North and South Carolina said.

"Storm readiness and disaster preparedness, particularly in the Southeast, are major factors for people in going solar," said Tyson Grinstead, Southeast director of policy for Sunrun, a company that leases rooftop solar panels. "As we see more and more storms, we're seeing more and more customers come to us and see what their options are to provide for themselves."

In Florida, Sunrun has had success with systems that include solar panels and a storage battery, Grinstead said. A battery acts much like a generator and can keep critical appliances running during a power outage. 

Sunrun, which is the largest leased solar panel provider in South Carolina, reported no effects from Florence in that state. (The company doesn't operate in North Carolina.) NC Solar Now, the largest solar provider in North Carolina, also reported no issues during Florence. Yes Solar Solutions, which has close to 3,000 megawatts of solar installed in North Carolina, received several inquiries during the storm from customers wanting to install solar systems, GTM reported. Only six of the company's 800 customers reported problems after Florence. 

Blowing in the wind

"A hurricane can be either really good news for wind generation or too much of a good thing," said Wade Schauer, a research director at Wood Mackenzie Power and Renewables. North Carolina's only wind farm, the Amazon facility near Elizabeth, powered through the storm, even generating electricity through part of it.

"The wind farm experienced no damage and no noticeable water or drainage issues," said Paul Copleman, a spokesperson for Avangrid Renewables, which owns and runs the farm. The result would have been different if Florence had hit the farm directly, he noted -- the facility is in the northeastern part of the state, and Florence turned south along the coast.

A U.S. wind farm experienced a hurricane directly last year, when Hurricane Harvey shut down several wind facilities on the Gulf Coast of Texas. But they powered back up within days, The Wall Street Journal reported, while several refineries shut down and coal-fired power plants flooded.

Hurricane-force winds do have the power to take apart wind turbines, as happened in China in 2013, but newer turbines are very wind-resistant, with one model designed to operate in a typhoon.

"Major manufacturers are basically designing typhoon-rated wind turbines, for really, really heavy winds," said Burgess, pointing to examples in the North Sea. "Anything installed in the last couple of years, they are very, very resistant to wind and extremely resistant to flooding," he said.

The need for more storm-resistant equipment is clear: More and more wind farms are being built near the coasts at the same time that storms become stronger and more frequent.

Still, because wind farms connect to a grid, they won't protect against the outages caused by transmissions breakdowns. That's another vote for battery power, Burgess said.

"When transmission lines are down, it doesn't matter how many power plants you have," he said. "What's more important at that moment is that your critical facilities -- hospitals, shelters, ATMs -- they have local power."