Solar Panel Durability And Performance In Extreme Weather Conditions
Extreme weather events are increasingly common across the globe. Therefore, solar companies must take certain precautions to protect PV equipment and ensure safety while promoting clean energy production.
“We have a choice to build solar systems that can provide reliable electricity even when we have extreme weather damaging the grid,” said Dirk Jordan, senior reliability engineer for the National Renewable Energy Laboratory (NREL). “Certifications, including education and utilizing the best practices for regional extreme weather, will pay for themselves with cost-saving electricity."
Solar panel durability encompasses weather resistance, mechanical strength, equipment longevity, reliability, resistance to degradation, equipment warranties, and certifications. Let’s examine this critical topic, so you can better serve your solar energy customers.
Overview: Types Of Solar Panels
There are many types of PV modules used for residential and commercial solar power projects.
Monocrystalline solar panels are made from a single crystal structure, usually silicon, and have a black appearance. They tend to be efficient modules, but can be more expensive.
Polycrystalline solar panels are made from multiple silicon crystals and have a speckled blue appearance. They are generally less efficient than monocrystalline panels, but are often more cost-effective.
Thin-film solar panels use a different manufacturing process that involves depositing layers of semiconductor material onto a substrate such as glass or metal. They can be flexible and lightweight, and can be transparent or semi-transparent. Thin-film panels typically are less efficient than crystalline panels but perform better in low light conditions and at high temperatures.
Building-Integrated Photovoltaics (BIPV) are designed to seamlessly integrate into building materials, such as solar roof tiles or windows. They serve both for generating renewable energy and as a structural component of the building.
What Are Solar Panels Made Of?
PV modules are designed to withstand extreme weather events, such as hailstorms, wind, and snow loads. Numerous elements help protect the lifespan of solar cells from moisture, UV radiation, wind-blown debris, structural damage, and other weather-related hazards that can reduce their lifespan.
Solar panels commonly consist of the following:
Photovoltaic cells are made of a semiconductor material that converts sunlight into solar electricity.
Encapsulation protects the delicate photovoltaic cells from environmental factors and prevents moisture from entering the panel.
The backsheet layer provides electrical insulation and protection from moisture, humidity, and UV radiation.
The frame often consists of aluminum or steel and provides structural support. It protects the components from mechanical stress and helps securely mount the panels to a racking system.
The glass cover is made of a tempered glass cover on the front side of the panel to protect it from weather conditions and debris.
Many of these materials and design features increase solar panel durability and their ability to withstand extreme weather events. The encapsulation, backsheet, and glass cover protect the internal components from moisture, humidity, and UV radiation, which can cause damage over time. The frame provides structural integrity, while the tempered glass cover sheet offers resistance to impacts from hailstones, wind-blown debris, and other weather-related hazards.
What’s The Relationship Between Solar Panels And Temperature?
As the temperature increases, the efficiency of solar panels tends to decrease, resulting in a decreased solar output. The decrease in efficiency with rising temperature is primarily due to the behavior of the semiconductor materials in the photovoltaic cells.
The temperature coefficient is used to quantify this relationship and usually uses 77° F or 25° C as a reference temperature. It represents the percentage decrease in the power output of a solar panel for every degree Celsius increase in temperature above 25° C.
The temperature coefficient typically ranges from -0.2% to -0.5% per degree C but varies by the solar panel type and module quality. Thin-film solar usually has a lower temperature coefficient than monocrystalline and polycrystalline solar panels, so it performs well in hot weather.
How Solar Panels Perform In Extreme Conditions
Solar panels are designed to withstand a wide range of weather conditions and can generally perform well in extreme environments. However, certain factors, such as soiling, heavy rain, snow, hurricanes, and other severe weather conditions, can affect solar electricity output. Appropriate design, installation, and maintenance practices can help mitigate these effects. Refer to the PVEL PV Module Reliability Scorecard for information on how specific models perform.
The accumulation of dust, dirt, or other particles on the surface of solar panels can reduce the amount of sunlight reaching the solar cells. Soiling can be more pronounced in dry, dusty climates or near industrial sites. Solar panel cleaning can help address this issue, increasing renewable energy production.
Although rain clouds reduce solar energy generation by obscuring sunlight, rainfall can also positively affect solar panel performance. Rainwater helps wash away dust and dirt, improving solar panel efficiency. Solar inverters can be sensitive to lightning, so use a surge protector and shelter them when possible.
Snow accumulation on solar panels poses a challenge as it covers the surface and reduces the amount of sunlight reaching the cells. In regions with heavy snowfall, solar panels are often installed at an angle to encourage snow to slide off. Additionally, PV modules are designed to be durable and withstand the weight of snow loads according to local building codes and standards.
In some cases, periodic snow removal may be necessary to restore optimal performance.
Hurricanes And High Winds
Solar panels are designed to withstand high wind speeds and are typically tested according to international standards such as the International Electrotechnical Commission (IEC) 61215. This standard evaluates the mechanical strength of PV panels by subjecting them to simulated wind conditions. Panels that meet these standards are designed to resist damage from hurricanes and other severe wind events.
Proper conduit routing and electrical installation are critical to ensure the safety and performance of solar panel systems in areas prone to flooding. Electrical components and connections can be designed to be waterproof or housed in weatherproof enclosures. Conduit routing is carefully planned to avoid flood-prone areas, and if necessary, additional measures such as elevated mounting or flood barriers may be implemented. It is important to adhere to local building codes and regulations specific to solar panel installations in flood-prone areas to ensure longevity and safe operations.
Inspecting Panels After A Weather Event
After a weather event, it is crucial for solar installers to thoroughly inspect solar energy systems for any potential damage. Here are the important steps:
Ensure personal safety: Before beginning any inspection, look for downed power lines or other hazardous conditions. Notify the relevant authorities and follow appropriate safety protocols as needed.
Visual inspection: Visually inspect the solar panels for any obvious signs of damage, such as cracks, shattered glass, or loose connections. Check if any debris, like fallen branches, has made contact with the panels. Additionally, inspect the panel's frame for any signs of bending or deformation.
System shutdown: If there are any visible signs of damage, shut down the entire solar array to prevent any electrical hazards.
Grounding and wiring: Inspect the grounding system and wiring connections for any loose, corroded, or damaged connections.
Mounting and racking: Check the mounting system and racking for signs of movement, damage, or misalignment. Look for loose or missing bolts, brackets, or other components, and verify the panels are still securely attached to the roof or the mounting structure.
Electrical testing: If the visual inspection reveals no apparent damage, it may still be necessary to perform electrical testing. Measure the voltage and current output of the panels to ensure they are within the expected range. Any significant deviations may indicate hidden damage.
Frequently Asked Questions
These are some of the top questions that solar customers may ask about solar panels in extreme weather conditions.
Are there solar panel warranties that cover extreme weather damage?
Solar panel warranties typically cover manufacturing defects and performance guarantees, not weather damage, because it falls under external factors beyond the manufacturer's control. However, warranty terms can vary between manufacturers, so it's essential to review the specific warranty from the solar panel manufacturer for accurate information. Homeowners' insurance policies often offer coverage for weather-related damage to solar panels as part of their property protection coverage. Advise solar customers to check with their insurance providers to determine the extent of coverage for solar panels under their policies.
Is there preventative or routine maintenance solar customers can do to prevent weather damage?
Yes, your customers can perform several tasks to help prevent weather damage. Depending on the roof and the homeowner, they may need to hire a professional to safely conduct some of these activities.
Visually inspect solar panels, the racking system, and any associated wiring for signs of physical damage, such as cracks, chips, loose connections, or exposed wires.
Remove any debris, such as leaves, branches, or dirt, from the surface of your solar panels. Accumulated debris can reduce the efficiency of the panels and eventually cause damage if left unattended.
Trim trees near solar panels because falling branches or excessive shade from trees can affect solar system performance and potentially cause damage during severe weather events.
Inspect the roof and mounting system for signs of damage, such as loose or corroded shingles, deteriorating flashing, or loose mounts, if homeowners can do this safely. Address any issues promptly to prevent roof leaks or structural damage.
Monitor system output using a solar monitoring system and check inverter readings for unexplained drops in solar output. Ensure your customers have the required login information to monitor their production data.
How long do solar panels last?
Solar panels commonly last for about 25 to 30 or more years. However, most solar panels still produce electricity at the end of 30 years, but at a lower rate due to age-related degradation. Some solar panel models degrade more quickly than others, so refer to the power performance guarantee for information on the degradation rate.
Conclusion: Solar Panels Are Built To Withstand The Elements
Not only are solar modules designed to stand up to extreme weather, but solar battery storage can even mitigate the impacts of power outages from such events. For example, tens of thousands of PV systems with solar batteries were installed in Puerto Rico after Hurricane Maria. There are best practices that solar installers and homeowners should follow to prevent damage to solar systems from extreme weather.
Want to learn more about assessing a new solar site for prospective clients? Read our blog post on conducting solar surveys.