Solar panels can continue to function in various weather conditions, but extreme weather can impact their efficiency and, in some cases, can cause damage. While solar panels can generate power in bad weather, severe conditions may pose challenges. Here's a breakdown of how different weather conditions affect solar panel production:
- Cloudy and overcast days: These conditions reduce sunlight intensity, leading to decreased energy production. However, it doesn't cause physical damage, and efficiency typically returns when skies clear.
- Rain: Solar panels can still produce energy in rain, albeit at least 50%f less and in strong rain as much as 70% less. On a positive rain can also clean panels, improving performance afterward.
- Snow: Snow accumulation blocks sunlight from reaching solar cells, rendering the panels pretty much inactive until the snow melts or is cleared. Very very heavy snow can also cause structural damage.
It's crucial to have solar panels installed by certified professionals and choose reputable brands with quality components to withstand extreme conditions. While weather can temporarily impact efficiency, most panels return to optimal capacity once normal conditions resume. Investing in high-quality, durable solar systems ensures resilience against various weather challenges.
Is extreme weather dangerous for my solar PV system?
The simple answer is that solar panels and as such a full solar system can still function in extreme and bad weather conditions. However, extreme weather, which diminishes the available sunlight for your solar panels, will affect the efficiency of the panel’s energy production.
Although solar panels can produce energy in bad weather, during extreme conditions, damage may occur. This means that if you reside in a location where extreme weather conditions are common, having a solar installation that has extra safety features is very important. Otherwise, you may end up spending more than you expected for repairs.
For example, if you are located in areas that can have cyclones such as Townsville, Cairns or Darwin, your solar rails will require additional brackets to ensure the system can withstand the local wind forces. Your installer also needs to observe the clamp zones on the panels as recommended by the manufacturer. If these are ignored then the structural strength of the panel and framing system are compromised and in very heavy winds cracked glass or other panel damage is more likely.
If you purchase solar panels from a quality brand, the panels are tested for extreme weather conditions, including smaller hail stones, so always go for quality products and do not buy on price.
How do different weather conditions affect solar panel production?
Cloudy and overcast
The worst conditions for solar panel output are cloudy, overcast or rainy days. Although this poses no risk to the solar system physically, it reduces production and efficiency significantly.
Nevertheless, when solar panels are being produced and designed, manufacturers consider different weather conditions. This means they know that solar panels will be exposed to the elements. Thus, although cloudy and rainy weather are not favourable weather conditions in terms of production, its effects are only temporary, and it does not cause physical damage to the PV array.
Although solar panels can still produce energy when it’s raining, they are most effective when exposed to direct sunlight. You should expect your solar panels to produce roughly 15%-35% of their optimal production capacity on a rainy day. Of course, the amount of electricity produced on a rainy day will vary depending on how heavy the rain is. However, after the rain, your panels should, in most cases, work more efficiently since the water would have washed away any dust or dirt on the panel.
Usually, panels are rated IP67 or IP68, meaning even in driving rain the water will not enter the panel in any form. Only if the backing sheet, seals or lamination are broken will rain cause water ingress into the solar panel and via corrosion eventual failure of the solar module.
A less common weather condition in Australia, however, one that can cause issues, is snow. When snow accumulates on the panel, sunlight cannot get to the solar cells. This prohibits electricity from being generated. Although snow, if only lightly covering the panels will not cause any permanent damage, your solar panels will be inactive until the snow has been cleared or melted away.
The snow be allowed to build up to a solid height, the accumulated weight of wet snow can in extreme circumstances bend panels or their frames and could be the source of micro-cracks. Luckily such events are extremely rare in Australia
Hail can be one of the most dangerous extreme weather your solar system can face. During a storm, hail stones can vary from small ice pellets to large tennis balls, and the impact of these large ice balls can cause cracks and chips in your panels, damaging the panels beyond repair.
Modern solar panels are designed to withstand hailstones with a diameter of around 25 mm, but if the stones get bigger than that severe panel damage can occur. Luckily in such cases, the home insurance will cover the replacement of the panels.
Hurricanes, tornadoes and cyclones
This weather condition while not so common in Australia, has led to extreme damage such as cyclone Tracy in Darwin on Christmas day in 1974. Most solar panel manufacturers produce solar panels that can withstand wind speeds up to 220km/h. This is higher than Tracy – which was measured at 205 km/h and most tornadoes and hurricanes, which average 160 km/h. The main concern during these conditions is when other debris is flung around, and then hit the panels which can lead to cracked glass and therefore failure, as cracked panel glass can not be repaired.
If you are extremely unlucky, a lightning bolt may strike your panels or inverter. When and if this happens, extreme damage can occur to your system, with repercussions that range from a singular panel junction box or connector melting to the entire system being damaged and shutting down.
Manufacturers of inverters and panels as well as solar system installers do have to follow certain guidelines to minimise the equipment damage in such weather events. Please remember, that the chances of your panels getting struck by lightning are extremely slim, and such incidents are covered by your home insurance.
Solar panels can also be affected by extreme temperatures, both hot and cold. High temperatures can cause the panels to become very hot, which will temporarily reduce their efficiency. On the other hand, extremely cold temperatures are not such a big deal, as panels are designed to withstand temperatures of up to minus 20 degrees Celsius.
Allowances need to be made when installing solar panels to ensure a gap (usually 5-10mm) is kept between the panels to allow for room for the thermal-related expansion of panels under heat. Where panels are butted up hard against each other in an installation, such as two rows on top of each other, the expansion of panels caused by heat has been seen to create considerable pressure between the top and bottom panels. Eventually, such a poor install practice will lead to the shattering of the glass covering the panels.
Potential induced degradation
Heat combined with humidity can also cause a degradation phenomenon known as Potential-induced degradation. The high voltage combined with heat and humidity causes degradation of the cells in the panel at the high voltage end of the string of panels. This can be exacerbated in coastal areas where salt water can hit the solar panel.
An extension of this process is light and elevated temperature-induced degradation in which the combination of intense light, heat and humidity can lead to accelerated degradation of panel performance where the cell technology has not properly been pacified in manufacture. This has seen panels with performance drop of up to 30% over the initial five years or so after installation. If you want to read more about Potential Induced Degradation, refer to the GSES page on it here:
To make sure that you have a solar system that can withstand extreme weather conditions, make sure that you approach an installer who is CEC-certified, local and trustworthy, so install the panels with enough brackets, observe the clamp zones and do not butt panels hard against each other. Even high-quality solar components can lead to a bad and short lifespan solar system if the installer is poorly trained or just lazy.
Furthermore, make sure you pick panels as well as other components that are produced by a well-known brand so that you can have confidence in their quality and warranty abilities.
Overall, most solar panel manufacturers produce panels to withstand extreme weather conditions. Although certain conditions will reduce the efficiency of the panels, in most cases, this is only temporary, and your panels should return to maximum capacity shortly after the weather has returned to normal.