Solar panels are expensive and sometimes vital pieces of home equipment. Though uncommon in most regions, hailstorms are undoubtedly one of solar panel owners’ biggest fears. The last thing they want is for existing or new panels to get damaged or derailed in a storm. Solar panels are costly to replace and, while non-operational in the interim, can also affect power supply.
There is good news and bad news. The good news is that most solar panels are built to withstand a little hail. And the bad? The bad news is that hail can damage solar panel modules in specific situations. Those looking to find out more about how hail can affect solar panels have come to the right place!
In this post, I’ll discuss the interaction between hail and solar panels. Plus, which types of panels are the hardest and some tips on how to protect them.
What Is Hail and Why Does It Occur?
- Hail is formed when moisture gets pushed upwards by drafts and freezes together in the cold upper regions of thunderstorm clouds.
- The heavy hailstones drop down to the ground from high up, gaining momentum and finally hitting objects in their trajectory.
- On average, hailstones measure around 0.2″ in diameter and can be round, elliptical, or jagged, featuring a smooth or rough surface.
- However, hailstones can measure up to 5.9″ in diameter. Like a snowball, the hailstones can gather additional moisture and mass based on the conditions in which they form.
- Hailstones can damage objects such as vehicles, buildings, and crops. Hailstorms also pose a risk to the safety of people and animals outdoors.
What Is the Link Between Hail and Climate Change?
Some countries and areas, such as Nebraska, Colorado, and Wyoming in North America, receive more hail than others. However, climate change is expected to affect the hailstorms frequency, patterns, and severity globally in low- to high-risk areas. While hail is projected to decrease in North America and Asia due to climate change, scientists claim it may increase in currently low-risk continents such as Europe and Australia.
Are Solar Panels Able to Withstand Hailstorms?
Worrying about hailstorms damaging existing solar panels or a new setup getting installed is understandable. However, solar panel owners will be glad to know that quality panels generally get tested and built to withstand regular hail. Using select materials and construction processes, manufacturers can produce solar panels that can withstand the force.
How Are Solar Panel Modules Tested for Hail Resistance?
Most solar panel manufacturers submit their solar panel modules to a test called the “Solar Hail Test” or “Solar Hail Impact.” Machinery gets used to hurl real or mock hailstone ice balls at solar panels. The hailstone projectiles are usually fired at the international standard of 50 mph but can get shot out faster or slower.
Other tests include firing tennis balls at the panels, standing on them, driving cars over, and submerging panels in water. The panels should be waterproof and able to withstand weights of at least 113 lbs. per square foot. Of course, tests and results vary per solar panel, type, quality, and manufacturer, but generally, solar panels are hardy and durable.
When Can Solar Panels Get Damaged by Hail?
That said, the solar panel modules’ encapsulation materials, which get explained below, will affect how hail-proof it is. Additionally, the force and size of hailstones and the severity of the storm can increase the likelihood of damage.
Generally, hailstorms featuring stones of 1″ or more in diameter increase the risks of damage. However, the speed at which the hailstones are traveling is also a contributing factor. As the speed affects the force of the impact, even smaller hailstones may do damage in a severe storm. Hailstones generally travel at 10 up to 75 mph, doing more damage at the higher end of this spectrum.
What Materials Are Solar Panels Modules Made From?
Solar panel modules generally consist of solar cells. However, these may be encapsulated and framed in other layers of materials for additional protection. Generally, PV solar panel module consists of solar cells within layers of encapsulant covered with a frame and glass on top and protected underneath by a multi-layer protective back sheet.
1. Types of Solar Cells
Solar panels are generally either crystalline silicon or thin film, which differ in efficiency, construction, and cost.
Poly & Mono Crystalline Silicon Solar Panels
Crystalline solar panels comprise small silicon cells usually mounted in a frame. In general, these solar cells are encapsulated in various layers, including a back sheet, encapsulant, and frame.
Thin-Film Silicon Solar Panels
Thin-film solar panels comprise amorphous silicon covered with plastic. They are generally the cheaper, lighter, more flexible, and easier to install of the two. However, thin-film solar panels are usually less effective at collecting energy than crystalline solar panels.
2. Types of Solar Panel Encapsulant
Encapsulant often gets layered over and under solar panel cells to form a solar panel module. The most common material used as encapsulant is EVA or ethyl vinyl acetate. It generally gets heated to polymerize it, forming a solid module along with the encapsulated solar cells.
3. Types of Solar Panel Module Glass
The glass inserted in a solar panel’s frame is the most protective against water and hailstone damage. However, it can get made of various types of glass that affect the efficacy of its protection against hail.
Tempered glass is the most protective option against hail. This glass gets formed using either thermal or chemical processes to improve the glasses’ hardiness. It is generally up to six times stronger than regular plate glass of its same thickness. Besides being harder, it also shatters in a safer manner in small shards while remaining mostly intact.
Plate glass is also commonly used in the construction of solar panel modules. Plate glass is much less hardy than tempered glass, meaning it may easily crack in a hailstorm. Once cracked, the interior of the solar panel can get further damaged by hail and water leaking into the module.
4. Solar Panel Module Frame Materials
Solar panel frames are usually made of welded or modular metal pieces. The frame may also be a unique shape depending on the installation area and feature holes or ridges for easier installation. Solar panel frames can be made of various materials like wood, but the top choices are weather-resistant metals.
Aluminum is a top choice for solar panel frames. Note that aluminum may get dented in a very severe hail storm. However, it is still one of the most cost-effective and lightweight solutions and sufficiently protective. Ultimately, the frame will only protect the corners of the solar panel module and still won’t shatter like glass.
Stainless Steel Frames
Stainless steel is probably the most durable and hardiest choice for a solar panel frame. However, frames made of this metal can be very expensive. It’s also much heavier than aluminum, thickness for thickness.
5. Solar Panel Module Backsheet Materials
Solar panel modules also require protection underneath, not just on top. A solar panel back sheet offers the required insulation from moisture, mold, and electrical voltage that may damage or erode a solar panel. As the back sheet is underneath, it is less of a consideration when it comes to hail. However, the back sheet quality and materials are still an important consideration for solar panel owners wishing to extend the lifespan of their panels.
How to Protect Solar Panels from Hailstones and Storms
Allowing solar panel modules to get damaged in a hail storm isn’t necessary. There are various steps solar panel owners can take to protect theirs.
1. Enclose Solar Panel Modules with Tempered Glass
As mentioned before, tempered glass is the hardier option for solar panel module enclosures. Choosing or replacing existing plate glass with tempered glass is one step to take to protect against mild to moderate hail.
2. Apply a Methacrylate Coating
Methacrylate acts as an effective guard against light hail impact. Applying a layer of this coating can limit damage to solar panel modules while still allowing light through.
3. Ensure Hail Damage Is Covered by the Warranty or Insurance
Many solar panel modules have warranties, but not all cover hail damage. Investing in solar panels with the best warranty against hail can reduce replacement costs in the event of hail damage. However, home insurance with adequate hail damage cover will probably be the best bet long term.
4. Choose Hardy UL 61730 or IEC 61730 Rated Panels
The best quality-manufactured solar panels generally get tested for hail resistance. However, the type of test, testing company, and results vary. Look for solar panels rated UL 61730 (North America) or IEC 61730 (International), as these are currently the most rigorous hail testing standards. Solar panels that earn these ratings can generally withstand hailstones sized 1-3″ at speeds of 16.8-88.3 mph.
5. Invest in a Temporary Solar Panel Cover
Solar panel covers are another defense against hailstones and damage. These covers come in hard-shell and soft padded options. Hard-shell covers protect against hail impact and water, while padded covers absorb and soften some hailstone impact.
6. Take Into Account Local Weather Patterns
Anyone living in an area with frequent or severe hailstorms should think twice about solar panel safety. Though it is completely viable to install panels, extra precautions must be taken to protect them. Tempered glass, the highest-quality panels, a hard-shell cover, and comprehensive hail insurance may be necessary. Those living in low-risk areas also need to take protection into account due to climate change. Possible future weather pattern changes and freak weather could take solar panel owners by surprise.
7. Install Solar Panel Modules on Adjustable Frames
Hailstones generally hit and do damage to solar panels due to their angle. Installing panels on an adjustable frame that tilts vertically during storms can help reduce hail damage.
Solar panels are harder than assumed, but there are some instances where they can get damaged by hail. Severe storms featuring bigger hailstones, or those traveling at faster speeds, can result in costly damage. However, there are a few effective things solar panel owners can do to protect theirs.