Are renewables stormproof? Hurricane Sandy tests solar, wind.

Renewable energy may one day offer consumers relief from the widespread blackouts that have become a predictable by-product of major storms. The flexibility of wind and solar, combined with the decentralization of a microgrid, offer a degree of resilience not found in the top-down, traditional generation system, clean energy experts say.

Efforts are already underway to harness solar’s unique characteristics to help victims of hurricane Sandy, which devastated large swaths of New Jersey and New York and left millions in the dark.  

On the Rockaway Peninsula in Long Island, the Solar Sandy Project is supplying mobile solar generators to an area where the Long Island Power Authority has struggled to restore power. The generators do not need refueling and can be used to charge phones, heat food, and run other critical equipment, the organizers say.

Still, most solar and wind resources are reliant on the larger power grid, making them just as vulnerable to failure from extreme weather as traditional systems. And wind and solar, by their very nature, are directly exposed to the elements, unlike traditional power systems, which can be enclosed in buildings or buried underground. Tested by hurricane Sandy late last month, most renewable energy installations in New Jersey and New York seemed to escape major damage. 

Solar disarray

 
Hurricane Sandy’s impact on a rooftop solar array in Gloucester City, N.J., demonstrates the downside of solar’s exposure to nature’s elements. The 1.1 million square foot photovoltaic installation was damaged when Sandy bore down on what the owners say is North America’s largest rooftop solar array.

A photo taken Nov. 2 from an airplane by Alexis Kwasinski, a professor at the University of Texas at Austin, shows portions of the array missing or damaged.  

Holt Logistics Corp., which represents transportation and logistics management companies and owns the damaged array, downplayed the extent of Sandy’s impact.

“The photos you reference are dramatic but reflect only a small fraction of the vast solar field, less than 5 percent,” Thomas Holt III, a representative for Holt, told The Christian Science Monitor in an e-mail.  “[P]ower was and is pumping uninterrupted. Already the manufacturer SunPower is hard at work to replace the ones that were damaged and making better an already great project.”

Completed in April 2012, the $42 million project consists of 27,526 photovoltaic rooftop solar panels and has the capacity to produce nine megawatts of electricity. The project received nearly $11 million in federal tax credit rebates through the Department of Treasury’s Section 1603 program – part of the American Recovery and Reinvestment Act of 2009.

SunPower, the manufacturer of the panels, declined to comment on specific customer projects for privacy reasons, but said they saw predominantly limited to no damage to their systems from hurricane Sandy.

“[T]he overall damage to SunPower solar systems that were properly installed per the company’s manufacturing and required design guidelines is quite limited and more systems are coming back on line daily as the grid returns to normal,” said Jorg Heinemann, an executive vice president at SunPower, in a statement e-mailed to the Monitor.

Mr. Kwasinski, who studies the effects of natural disasters on critical power infrastructure, speculated that wind pressure may have built up under the panels, causing them to strip away from the array.

Neither Holt nor SunPower offered specific causes for the damage, though Mr. Heinemann said the company rigorously tests its solar panels for possible weather-related stresses and guarantees panel installations to withstand winds of 110 miles per hour and, in high-wind locations, 145 m.p.h.

The highest wind speed recorded by the National Weather Service in the state of New Jersey during hurricane Sandy was 90 m.p.h.

Weathering the storm

The Gloucester City incident appears to be the exception, rather than the rule.

Aggregate data can be difficult to collect, since many solar and wind installations are privately owned by individual residents and businesses, but industry experts said they heard of only minor structural damage to renewable energy systems.

Monique Hanis, director of communications at the Solar Energy Industries Association, said she heard of some damage anecdotally from the trade association’s members, but nothing substantial.

Ara Agopian, president of SolarInsure, a renewable energy specialty insurance broker, reported a low claim history from property loss in the wake of Sandy.

Sandy’s impact on ConEdison Solutions, the renewable energy subsidiary of Consolidated Edison, amounted to “truly, relatively minor damage to a handful of panels,” according to Christine Nevin, director of media relations for ConEdison Solutions.

Of the 22 solar farms run by Public Service Electric and Gas Co. in New Jersey (not including customer owned systems), four sustained various degrees of damage, according to Fran Sullivan, spokesman for the publicly owned utility.

While much of the damage was minor, Mr. Sullivan said a 3.2 megawatt solar farm in Linden, N.J., was severely damaged when it was submerged under seven feet of water, despite being built above the 100-year flood-plain mark.

However, even the flooded plant in Linden had little direct effect on customers, Sullivan said.

“If you lose one of these [solar] plants, it’s something we’re going to be able to backfill with standard generation,” he said.  

Wind turbines, which are shut down in high winds, appear to have endured Sandy with equal or greater success. Wind farms in Cuba sustained wind speeds of up to 110 m.p.h. and sustained no major damage, according to the World Wind Energy Association, based in Bonn, Germany.

Five turbines just outside Atlantic City, N.J., were put into “hurricane mode” during Sandy and were generating 1.5 megawatts of electricity soon after the storm subsided, according to OnEarth Magazine, a blog and quarterly environmental magazine published by the Natural Resources Defense Council in New York.

Built to last

Experts attribute the low percentage of reported damage to the developing technology and advanced engineering that goes into designing and building wind and solar systems.

Photovoltaic cells are covered by durable glass to prevent it from hail or foreign objects blown about by the wind, experts said. Still, not even the toughest glass can withstand larger chunks of hail or tree limbs, and manufacturers must walk a fine line between using glass strong enough to be protective but not so thick it weighs heavily on a roof or significantly reduces solar absorption.

When wind speeds exceed 50 m.p.h., turbines can be locked and the blades angled out of the wind so as to minimize damage, said Kevin Kaminski, a senior vice president, at Energi, a holding company based in Peabody, Mass., that provides risk management and insurance brokerage services to energy firms. Lightning rods are installed to divert the energy of a strike, Mr. Kaminski said.

Geothermal is virtually stormproof, energy experts said. Systems that draw on heat from the earth’s core to generate power are predominantly underground and protected from much of nature’s wrath, excepting earthquakes and deep flooding.

If the occurrence of extreme weather events and the demand for renewables increase over the coming years, these systems are likely to be further tested, especially by storms with even higher winds than Sandy.