The ‘Hail’ You Say!
By Richard A. Florey
Marketing Director,
EcoVantage Energy, Inc.
www.ecovantageenergy.com
The Hail Question
One of the most frequently asked questions we hear about solar panels is, “do they
withstand hail?” The short answer to that question is, very well. Damage to solar panels from
hail is extremely rare due to the angles of most
roof-mounted solar panel installations, as most
impacts are glancing blows, not to mention the
casings are incredibly strong. For example, after
the recent hail storms in the Metroplex area, we
were contacted to come remove the unharmed
solar panels from a roof that suffered hail damage
so they could repair the shingles.
You Can’t Beat Mother Nature ... or can you?
The individual crystalline cells that make up
a solar panel are actually quite fragile. That’s
why high quality solar PV panels come with
glass or acrylic casings to protect the cells. Under
controlled test conditions, these protected panels
can withstand high velocity hail pellets shot from
pneumatic guns. Astonishingly, most high quality
panels can survive hail stones shot at speeds of
260 mph or more!
To put that into perspective, the terminal
velocity of an 8-centimeter hail stone is 110 mph.
That’s more than 50% less than what the highest
quality solar panels can tolerate. The terminal
velocity of a 1-centimeter hail stone is 20 mph
(the fastest speed that hail of this size can travel
when falling).
Rest Easy, You’re Covered
Though solar panels are tough, they are not
indestructible. So should your solar PV panels
ever become damaged; just remember that in
most cases, adding solar to your homeowners
policy is a required step in obtaining an inter-tie
agreement with your power company before you
ever install them.
Solar Panel Hail Test
What’s the Life Expectancy of Solar Panels?
It’s a fact that many solar panels manufactured in the 1970’s
are still cranking out respectable power. So what is a reasonable lifespan for solar panels? Well, according to a National
Renewable Energy Laboratory (NREL) study that examined the
long term degradation rates of various PV panels; for monocrystalline silicon, the degradation rate is less than 0.5% for
panels made before 2000, and less than 0.4% for panels made
after 2000. That means that a panel manufactured today should
produce 92% of its original power after 20 years. Panels in more
moderate climates such as the northern United States had degradation rates as low as 0.2% per year. Those panels could retain
96% of their production capabilities after 20 years. That’s where
the value is, as many panels have a 20-25 year warranty. Most
manufacturers agree that solar panels will perform admirably for
50 years or more. Don’t you wish everything you buy had such
resilience?