Protecting solar farms from the elements: Geohazard mitigation for large-scale solar farms
October 22, 2024
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The right geohazard-mitigation strategies can help protect large-scale solar farms from floods, bushfires, hail, and tropical cyclones
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From floods and fires to hailstorms and cyclones, large-scale solar farms are more and more vulnerable to geohazards. And climate change is amplifying the risks. As a result, weather resilience must be top of mind when designing and building large-scale solar farms.
It takes several strategies to protect our solar assets. We’ll explore how thoughtful site selection, followed by solutions like early warning systems, stowing for hail and wind, and innovative approaches—such as agrivoltaics—can improve the resilience of solar farms.
Site selection: Why it’s key to mitigate geohazards for large-scale solar farms
Mitigating geohazards for large-scale solar farms starts with site selection. It may seem intuitive to place solar farms in Australia’s people-free arid interiors. However, these areas often lack the infrastructure needed to make constructing them there practical.
The main question developers have is: How easily can a solar farm connect to the grid? This critical factor narrows down the list of potential sites. Without sufficient transmission lines or access to the grid, the high cost of upgrading or building this infrastructure—sometimes in the hundreds of millions of dollars—can quickly outweigh the benefits of a sunny, empty expanse of land.
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Our detailed surveys and design are helping a client in Kingaroy, Queensland, better understand the terrain, enabling them to proceed with their future solar farm.
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Once developers identify an area that could work, the process shifts to constraint mapping. This is where developers assess specific factors that determine where a solar farm can or cannot be built within a region.
For example, floodplains are obvious no-build zones. And areas prone to bushfires or important habitats, such as nesting grounds for protected flora or fauna, offer serious constraints. While the latter may not be a geohazard, it’s an important environmental concern that is part of planning.
At Kingaroy, an agricultural town in Queensland famous for its wine and peanuts, our team assisted a client looking to power local farms with renewable energy. By surveying the land and creating a concept design, we mapped out the region's geotechnical, structural, ecological, and flood risks. All this gave the client a better view of the lay of the land before it began construction.
Ultimately, it’s rare that sites are chosen because they’re perfect in every way, free from the risk of geohazards or other concerns. Rather, they’re selected because there are reasonable ways to mitigate the risks that do exist.
Hail: Geohazard mitigation strategies for solar farms facing an icy battering
Hail has been a particular challenge for solar farm development and operation. This is even more so as climate change sees the frequency and severity of hailstorms around the world increase.
In Texas, a 1,200-hectare solar farm copped severe damage during a hailstorm, in which baseball-sized hailstones smashed hundreds of its solar panels, reducing the farm’s capacity. Another solar farm in Nebraska was demolished after a severe hailstorm.
Large hailstones have enough kinetic energy to shatter the solar panel’s glass, according to the U.S. Department of Energy. Closer to home, a hailstorm in Queensland, where solar farms were struck by snowball-sized hailstones, caused over $28 million worth of damage to one solar farm.
" }Ultimately, it’s rare that sites are chosen because they’re perfect in every way, free from the risk of geohazards or other concerns.
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One insurer estimates hail-related damage accounts for more than half of all solar farm claims. Some insurers have even started refusing to insure solar farms because of the risk. So, how can we mitigate the risk of hail and safeguard investments in green energy?
One way is increasing the thickness of glass panels. As the development of solar farms has accelerated, the panels have gotten larger while the glass has gotten thinner. Increasing the thickness of the glass would make it less susceptible to damage.
Another option is ‘stowing’. This is where the solar panels are moved into a vertical position, reducing their exposure to the hail. Weather stations are essential to solar farms. They monitor cloud cover and sunshine, but they can also detect adverse weather events. In the case of hail, weather stations and early warning detection systems can automatically move the panels into a hail-stow position before a storm hits.
Cyclones: Reducing the risk of damage from gale-force winds
Wind is another of the major risks faced by solar farms. We’re not talking about a warm summer breeze here. We’re talking about the gale-force winds that accompany tropical cyclones and have the power to rip solar panels clear out of the ground.
Climate change means tropical cyclones—much like hailstorms—are increasing in frequency and severity. The Australian Climate Council notes that the maximum wind speeds associated with cyclones are climbing.
That’s why we’ve started conducting pull-out tests on solar farms to determine whether the solar panels are going to take off when a storm hits. These tests help us understand how strong the anchors or bolts holding a solar panel into the ground need to be, so we can ensure they don’t loosen too much when struck by strong winds.
Stowing can also protect solar panels from fierce winds. However, in this instance, the solar panels are tilted into the wind, which reduces the amount of wind they’re catching.
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Hail damage on a solar panel.
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Bushfires: Mitigating fire risks from solar farms in Australia
In Australia, where bushfires are a common summer threat, managing fire risks is crucial when developing solar farms. These risks are twofold: the potential for a solar farm to spark a bushfire and the vulnerability of the solar farm itself to bushfires. The primary concern is often the former—preventing solar farms from sparking fires.
This is especially true in rural areas. As compared with urban areas, the back of solar panels in rural areas often have exposed cables and other electric components. With voltages reaching up to 1,500 volts, these components can pose a fire hazard. Solar farms located near bushland are at the highest risk, and in these cases, bushfire consultant assessments sometimes require a 20-metre setback. It’s also important to reduce the fuel load around solar panels—mainly grass—by making sure it’s mowed regularly.
One surprisingly effective way to do this? Sheep.
Through ‘agrivoltaics’, where we use the land for both renewable energy and agriculture, sheep grazing can help maintain vegetation under the panels. This not only reduces fire hazards but is also a cost-effective alternative to mowing. Sheep keep the grass short, preventing overgrowth that could otherwise fuel fires. It’s a practical, low-maintenance solution to what would otherwise be an expensive upkeep task for solar farms.
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Grand Ridge Solar Farm produces renewable energy while also contributing to the local ecosystem.
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Flooding: Best practices for solar farm construction in flood-prone areas
It’s important to avoid flood plains when selecting a site for a solar farm. From an electrical engineering standpoint, we typically rely on flood modelling experts to ensure that water levels won’t reach the farm. However, extreme flooding events can still catch us by surprise, and the greatest threat isn’t to the panels themselves but to the on-site transformers and substations.
One common geohazard mitigation strategy in this instance is to raise the height of solar arrays and critical structures, placing them on plinths to keep them above potential floodwaters. Each network authority has its own standards. Western Power, for instance, requires assets to be placed above the 1-in-100-year flood level, protecting them against what’s seen as the worst possible level of flooding.
Even with raised arrays, underground cables are still vulnerable. If submerged, these cables can suffer significant damage, making floodplains a high-risk option for solar farm construction.
In some cases, agrivoltaics can offer additional protection against flooding. At the Grand Ridge Solar Farm in the US, the owners integrated native prairie plants into the design. This not only provides habitats for bees but also helps manage stormwater—and it looks good too.
Protecting large-scale solar farms with geohazard mitigation strategies
Climate change is here. If we want to get to net zero, large-scale solar farms will continue to play a critical role in the transition to renewable energy. Protecting these farms against geohazards is vital for their long-term durability and performance. That way, they can keep providing us with sustainable energy well into the future.
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