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?