Utility-Scale Solar Can Withstand Severe Hailstorms. Here’s How

As Texas becomes the country’s leader in generating solar power, the state’s propensity for severe hailstorms is a hazard that energy companies aim to manage.

I’m writing about solar and hail this week, not because of any incident, but because of a lack of incidents. We are near the end of the spring and summer hail season and there has been no high-profile hailstorm that wrecked solar panels.

If there had been, you probably would have heard about it, considering the Trump administration’s enthusiasm for highlighting any supposed problems with renewable energy.

Some of this lack of damage may be good luck. But some of this is likely because of improvements in the way solar companies assess their risk and take steps to avoid severe losses.

The solar industry has improved the durability of panels and developed testing methods that help answer questions about how certain panels will perform when slammed with hail. Much of that testing occurs in a lab in California’s Bay Area where technicians fire balls of ice from a “hail cannon” and then review the damage.

I spoke with Brian Grenko, CEO of VDE Americas, about what happens in the lab and how his company is using the results.

“If you really want to understand how a solar panel, or how anything, can withstand hail, you have to test it until it breaks,” he said. “Otherwise, you don’t really understand the actual properties.”

His company is a technical consultancy based in San Jose, California, a subsidiary of VDE Group of Germany. The testing is done by another VDE Group subsidiary, Renewable Energy Test Center, or RETC, which has a lab in Fremont, just down the road from San Jose.

RETC’s employees get to fire the hail cannons and VDE’s employees do a lot of math based on analysis of the results.

This month, the companies announced that they have jointly developed a new test of hail resiliency. Lab employees simulate a hailstorm, with varying wind speeds and sizes of hailstones. The goal is to determine how much punishment a solar panel can take before it breaks, and also to see which part of the panel is the first to break.

Using the test results, the teams create a report that shows the probability of a panel’s failure as the impact energy from hail increases.

The detail in the results is in contrast to what would otherwise be available. Solar panels must meet international testing requirements that were updated most recently in 2016.

These requirements were not written with hail in mind, Grenko said.

Solar companies, banks and insurance companies use data from the test to determine a solar project’s risk of hail damage and how to reduce that risk. For example, a developer may find that hail risk is high enough to invest in panels that are more expensive and durable.

But there is more to this research than determining the strength of materials. As I wrote last year, one way to reduce hail damage is to use trackers—systems that shift the panel angle to follow the sun—that have a “stow” mode with a vertical angle to avoid direct hits from hail.

Simply having a stow mode isn’t enough, though. The operator of a solar project needs to have access to high-quality weather reports that provide a warning of incoming hail. And, the operator needs to push the button to shift into stow mode or have an automated process in place to do so.

If that doesn’t happen, the result can be a situation similar to what happened last year at the Fighting Jays solar project in southeast Texas, where thousands of solar panels were destroyed. Right-wing news outlets highlighted the damage and interviewed neighbors who spoke about their fears of environmental damage from chemicals leaking from the panels. (I have seen no evidence from reputable sources that leakage from chemicals in solar panels is a danger to human or animal health.) 

Texas’ solar power growth has happened in spite of its vulnerability to hail damage. A cluster of states from North Dakota to Texas has the highest frequency and severity of hailstorms, according to the Federal Emergency Management Agency. Hail is most common in places that also have a high incidence of severe thunderstorms and tornadoes, which is tied to a region’s topography, according to the Midwest Regional Climate Center at Purdue University.

Grenko explained that most early utility-scale solar development happened in places like California and Arizona, which have a low risk of hail. Then, as the prices of solar panels fell in the 2010s, the industry expanded to many other places, including those with higher hail risk.

A key event in understanding the risk happened in May 2019, when a hailstorm wrecked about 400,000 of the 680,000 panels at Midway Solar Project near Midland, Texas. The insurance loss was about $70 million.

The size of the loss led solar companies, lenders and insurance companies to realize that they may have underestimated the risk of hail.

Midway “was the one that kind of started it all” for understanding the threat of hail to utility-scale solar, said Daniel Schreiber, a Texas-based meteorologist and senior vice president for J.S. Held, a consulting firm whose work includes assessing large insurance claims.

He is aware of the various steps the solar industry is taking to be ready for hailstorms. One concern he has is that hailstorms often have high winds, and the stow mode used to reduce hail damage may not be well-suited for reducing wind damage.

“When you have a storm that’s coming at you, that’s going to have both strong winds and large hail, what do you do?” he asked.

He thinks the answer is to have high-quality weather information so a solar project operator has a sense of how severe the wind and hail are in a storm, and can decide which threat poses the greatest risk.

If solar companies can better understand their hail risk and take steps to mitigate that risk, that’s good news for Texas.

The state is in a virtual tie with California for having the most electricity generation from utility-scale solar in the first half of this year, as I reported last week. And, based on the number and size of projects in development, Texas is poised to pass California.

I am not suggesting that hail is a non-issue. Researchers have indicated that the severity of hailstorms is likely to increase due to climate change. And hail can be devastating for the roofs of homes and cars.

But the solar industry now has tools to respond to anyone who dismisses Texas’ potential by saying, “What about hail?”

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Other stories about the energy transition to take note of this week:

Tesla Unveils the Megablock, a Big Battery for the Grid: Tesla has announced a new energy storage product, the Megablock, which holds 20 megawatt hours, as Julian Spector reports for Canary Media. The company revealed the product at the RE+ renewable energy conference in Las Vegas. The Megablock is made up of four of Tesla’s Megapack energy storage systems around one transformer, with a design that is meant to be easy to ship and install for companies building utility-scale energy storage. 

Solid-State Batteries Are Coming Soon in These Vehicles: Automakers continue to make announcements about next-generation batteries and their timelines for release. Some of those plans involve solid-state batteries, which use a solid electrolyte instead of a liquid or gel, and have the potential for much higher ranges than current batteries. Suvrat Kothari reports for InsideEVs.com about which models have the batteries or will soon have them. This includes several Chinese models that are unlikely to reach the United States, but also from brands such as Dodge, Mercedes-Benz and BMW, among others. One of the main themes is that solid-state batteries are still a few years from being accessible in models that a typical U.S. buyer can afford.

Can the Whimbrel and Wind Turbines Coexist? Researchers are looking at how the construction of a large offshore wind farm off the coast of Virginia may affect the whimbrel, a brown and tan shorebird, as my colleague Charles Paullin reports for ICN. This research is sponsored by environmental organizations in partnership with Dominion Energy, the owner of the offshore wind farm. It illustrates what Paullin describes as a situation in which the turbines could harm the birds, while the emissions reductions that stem from offshore wind will be helpful to the birds in the long run.

Inside Clean Energy is ICN’s weekly bulletin of news and analysis about the energy transition. Send news tips and questions to [email protected].