Solar Panels and Hail: Can My Solar Panels Withstand a Hail Storm?

With zero moving parts, solar photovoltaic (PV) panels are one of the most durable energy generation technologies known to man. With minimal upkeep, your installation can continue operating at peak performance for decades. In fact, many solar installations from the 1970s are still generating clean, free energy for their owners.

So solar is durable but is it durable enough to withstand extreme weather conditions like falling hail?

The crystalline cells that make up most solar panels are actually quite fragile. Left exposed, they crack easily and can dramatically reduce the total power output of your system.

However, todays high quality solar PV panels usually come equipped with laminate, glass, or acrylic casing to protect the crystalline cells underneath. Under test conditions, these protected panels can withstand high velocity hail pellets shot from pneumatic guns.

In fact, SolarWorld’s new glass-glass protective casing can take on hail stones shot at velocities of 260+ mph. Just to put that into perspective:

• Solar panels designed around international standards can withstand hail stones traveling at 50 mph
• The terminal velocity of a 1-centimeter hail stone is 20 mph (this is the fastest speed that hail of this size can travel when falling from the sky)
• The terminal velocity of an 8-centimeter hail stone is 110 mph — more than 50% less than what the highest quality solar panels can tolerate

In other words, damage from hail is exceedingly rare. What’s more, solar panels don’t usually take direct hits from falling debris. Due to the tilted angles of standard roof- and ground-mounted solar PV installations, most impacts are glancing blows.

This brief 2-minute video illustrates how incredibly resilient today’s solar panels truly are. The panels featured in this clip endure everything from hail to baseballs to utility vehicles (yes — utility vehicles). Kinda puts solar panels and hail in perspective, doesn’t it?

So Is Weatherproofing Unnecessary for Solar Installations?

Although many of today’s leading panels are designed for extreme weather conditions, this doesn’t mean they can withstand everything Mother Nature throws at them. Proper mounting and racking are essential. This is especially true in in coastal areas that receive high velocity winds during tropical storm season. But as residents of Maryland, New Jersey, and New York discovered in the wake of Hurricane Sandy, even they’re not immune to freak super-storms. Those with poorly installed solar PV systems lost power just like everyone else.

So although most solar installations can endure a great deal of stress, there are important steps you should take to weatherproof your panels for extreme climate conditions. For a more in-depth look into solar weatherproofing, read Do I Need to Prepare My Solar Panels for a Super-storm?