# Solar Panels, Tornadoes, and Hail Storms



## thestartupman (Jul 25, 2010)

I am wanting to find out how solar panels do with tornadoes, and hail storms. Can they survive either of these types of storms? Is there anything that needs to be done to protect them when these type of storms are predicted? Any info anyone has good or bad about these types of storms, and solar panels would be greatly appreciated.


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## Energy Rebel (Jan 22, 2011)

Hailstorms, yes, especially the newer panels coming out now.
Tornadoes, if it's a direct hit, no.
You've seen the damage. If you can't keep your roof on the house, the panels are history, too.


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## WisJim (Jan 14, 2004)

The winds that they can survive depends on the quality and construction of the mountings of the panels. Quality panels should be able to survive any hailstorm that doesn't wreck the buildings the panels are on or near. My first panels survived hail that actually punched holes in the asphalt roof on my garage and shop building, back around 1987 or so. The panels weren't affected by that storm or any subsequent storms, and still work fine.


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## Jim-mi (May 15, 2002)

At one point in time one of the tests for a panel was to with stand the impact of 3/4" hail at 53 mph wind speed.

This was back in the times when the folks built real stuff . . . . before the crooks at Solandra(sp) got on the scene.

Wind . . . . . .depends on how well mounted the panels are...........

My pole mounted racks have with stood some really nasty storms..........


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## greg273 (Aug 5, 2003)

Tempered glass is pretty tough... 

Sad to hear the reports of the 'cheapening' of solar panel quality though. Is anyone in America making a decent panel now that Evergreen bit the dust? 

Just ran across this article about how even the Navy is allowing Chinese made panels to be used on bases... just amazing how backwards that really is. 
http://www.cleanenergyauthority.com/solar-energy-news/navy-not-seeking-usa-made-solar-panels-090711/


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## thestartupman (Jul 25, 2010)

I know this is a old thread, but I was hoping others might have some input now. I know there are probably a lot more systems installed since this was first posted. Thanks


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## SolarGary (Sep 8, 2005)

thestartupman said:


> I know this is a old thread, but I was hoping others might have some input now. I know there are probably a lot more systems installed since this was first posted. Thanks



I did a little looking into this for a friend a while back -- some extracts from what I found. I realize they are hard to read because of the cut and paste process and the pictures did not paste -- if you PM me I can send you the Word file...



Interesting paper on developing a Hail Gun to test PV panels 
Lots of good background information.
http://www1.eere.energy.gov/solar/pdfs/pvmrw12_poster_si_uselton.pdf

The combination of some of the hail gun tests plus the hail distribution map might be interpreted to say that the probability of hail damage to PV panels in MT is very small?



Overview article on hail damage issues:
http://life.gaiam.com/article/how-does-hail-affect-solar-panels
Post on the Wind-Sun Forum:
My city of Maryland Heights, MO, got pummeled during the hail storm that occurred
April 28th. Seven of my solar panels were destroyed, but amazingly, eight survived
without a scratch. The hail stones were the biggest I have ever seen in my life!

EDIT: I added a photo which shows the somewhat random distribution of the
destruction. Also note the smudges on my roofing shingles - those are the "hits"
that insurance adjusters count to determine whether you qualify for a new roof.
If you get more than 10 hits per 100 square feet, you qualify. A hit cracks the 
underlying fiberglass backing, which then allows it to leak. My neighbor's 
insurance adjuster counted 100 hits per 100 square feet on my neighbor's roof.

John

http://www.wind-sun.com/ForumVB/sho...-damage-from-hail-storm&highlight=hail+damage


Another Post on the Wind-Sun Forum:
Just had the worse hail storm I have seen in 20 years come through here. All 3 cars damaged, about half the screens on the house damaged, new building stucco has holes blown in it, some roof tiles pieces on the ground, BUT looks like the solar panels survived!!!!
Attached Thumbnails 
http://www.wind-sun.com/ForumVB/showthread.php?9426-What-the-hail-is-going-on!&highlight=hail+damage

Right now the angle should be almost less than 10 degrees because it has been summer time, but he had left them at about 25 to 30 degrees. Only one panel was damaged out of ten panels. Hailstones golf ball sized, for over fifteen minutes none stop. I feel he was very lucky to lose only one panel. Most panel manufactures say their panels will take a 1 inch hail stone at fifty mph. These hail stones were almost 1 1/2 inches, about half miile away they got over 2 inch hail stones. You can see where it hit, right at the edge where the glass just goes under the aluminum frameing. Oh well, another lesson learned, taught by mother nature. Arcandspark



SBM Solar modules mention hail resistance and certification: 
SBM advertises their panels as &#8220;shatterproof&#8221; . They are apparently not glazed with glass &#8211; but, they don&#8217;t say a lot about what the glazing material is.

A quote from the pdf below:
SHATTERPROOF 
SBM PV panel has been certified (IEC61215) for hail impact resistance. Glass breakage and the subsequent loss of power is a potential issue with glass PV panels during shipping, handling, installation and other hazardous environ-mental conditions. SBM&#8217;s panels are completely shatterproof even after hitting with a hammer, golf balls or shot with bullets from a gun. In most cases when panel surfaces were damaged, they still remain its integrity to function, producing power, without current leakage.
http://www.enfsolar.com/ApolloF/sol...ne/SBM Solar_250W Panel_ENFSolarDirectory.pdf

So, it looks like there are some panels that are specifically designed for increased resistance to hail damage.

Kyocera specifically mentions hail testing in their description: http://www.kyocerasolar.com/assets/001/5191.pdf
They don&#8217;t say what size hail at what velocity, but I&#8217;d guess they would tell you if you asked.

Sanyo&#8217;s data sheet also give hail test results:
Sanyo&#8217;s data sheet on the HIT modules says the panels are tested to 1 inch hail at 52 mph.
http://us.sanyo.com/dynamic/product/Downloads/HIT Power 215A-37918567.pdf

CoEnergy appears to test to a higher hail standard:
From their web page:

Structured Solar Glass
&#8226;	While other solar panels use glass coating or films that wear or breakdown over time, the PowerPlus solar panel has structured glass to maximize lifetime durability.
&#8226;	The PowerPlus solar panel&#8217;s structured glass can withstand a hit by a 2 inch hail ball traveling at 80 mph. This greatly exceeds testing requirements set for the industry.

So, it does look like there are some panel makers out there that have a higher hail standard. The 2 inch diameter at 80 mph is a LOT more energy than 1 inch at 50mph that seems to be common.

They offer a number of modules, and it&#8217;s not clear to me that all of them meet the higher hail standard.
URL for brochure: http://www.conergy.us/desktopdefault.aspx/tabid-206/429_read-715/


Mother Earth News: Can Solar Panels Be Damaged by Hail? 

http://www.motherearthnews.com/ask-our-experts/solar-panels-and-hail.aspx

My Overall Conclusions from the above:
It seems like the probability of hail damage even if you don&#8217;t take any precautions is small.
If you wanted to take extra precautions, I&#8217;d think about:
&#8226;	Use the Amorphous Silicon type of PV panels, as they are said to be more resistant to hail damage.
&#8226;	Look for one of the PV suppliers that offer PV modules designed for hail impacts above the usual 1 inch at 52 mph &#8211; eg the SBM modules.
Using one of the two approaches just above might make more sense than having a local installer add a layer of polycarbonate or Acyrlic over regular PV panels in that you probably won&#8217;t find anyone who would stand behind the effectiveness of an added layer, and adding the layer might have unforeseen consequences. The added layer would also come with an about 10% loss in transmission, while the thicker or more resistance glass in the PV module likely not have any added transmission loss.

Note: the friend was asking if it would make sense to add a layer of Acrylic over the PV panel glazing -- that's why the mention of an added layer above.

Gary


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## thestartupman (Jul 25, 2010)

Thanks Gary, you have a lot of good information here.


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