Solar panels are exposed to the sun and elements and face a number of environmental risk factors that we summarize in this article.
In another article we discuss the environmental risks of solar panels themselves. In other words, how green is solar energy when we take into account the toxic impact of production. In this article we are only considering the damage that environmental factors can cause panels after they have been installed.
Almost all of these risks are covered by insurance. As with most insurance, however, it is wise to alert the carrier before undertaking and completing a project. Most insurers will consider the panels no more risky than a chandelier, imposing no premiums for coverage. However, in rare instances – a region subject to frequent hail storms, for example — the panels might be viewed as facing increased liability and so could trigger additional premiums.
Heat is definitely not a factor for solar panels although efficiency is impacted by extreme heat more than by extreme cold. The reason for the difference in efficiency in hot weather is this: Solar panels work when the electrons located in the so-called valence band jump to the conduction band after being excited by the sun’s heat. When the panels themselves are hot the distance between the valence band and conduction band is decreased and so less electricity is generated. In fact, the efficiency of panels – i.e., the percentage of energy, generally around 20%, that is converted from sunlight to electricity – decreases by .05% for every 1 degree Celsius of increased temperature. 20 degrees of heat would therefore reduce efficiency by 1%.
Note that the cells don’t heat up to the same extent as the ambient air temperature. That is because the solar panels are made of glass and much of the heat is reflected or ventilated. Note, however, that a panel lying immediately above the roof’s surface will not ventilate as much as one that is surrounded by air.
Rain and snow have no impact whatsoever on solar panels except to the extent that the sunlight hitting the panels decreases as it does in darkness. The average amount of cloudy weather or precipitation is taken into account when the output of the panels is measured in a product’s design and engineering.
Even in rain and snow panels will continue to produce energy during daylight hours as sunlight will reach the solar cells except in deep snow cover.
Hail is probably the biggest risk to solar panels and can dent the glass that holds them. Researchers at the California Institute of Technology, working with NASA, concluded that solar panels that are not covered with acrylic can be affected by hail stones 1” in diameter whereas panels with acrylic facing are affected by 2” hail stones. Similar tests conducted by Arizona State University found that solar panels could withstand 1” hail stones fired at them at a speed of 50 miles per hour. One researcher even concluded that hailstones falling at 120 mph would not affect performance as long as the panel glass itself was not shattered or the frames bent.
Interestingly this last researcher also calculated that most hail storms involve northerly winds and therefore would not cause damage to most south-facing panels.
Wind can be a hazard for panels that are not secured properly. Installations in hurricane-prone regions are particularly vulnerable and must be adequately braced.
Recent news stories have raised concerns about the impact of fire. The risks of fire are no greater than for any structural fire and replacement insurance will be adequate to address this risk.
However, fire has caught attention because of the electrical hazard risk that it poses for firefighters attacking a blaze from the roof. We have heard that some fire departments may be reluctant to attack a fire because of the fear of arcing. In a large commercial installation the panels can pose an electrocution hazard to firefighters as they douse the building with water.
The National Fire Protection Association now runs webinars on the risks of solar panels. Legislation has been proposed to put signs outside buildings that warn firefighters of the risks. Firefighters are advised to disconnect from the grid (all systems have a kill switch that will sever the system’s interconnection with the utility grid). At the same time, caution must be exercised in and around the panels as they continue to produce electricity during daylight hours even if that Direct Current is not being captured and put to use.
The risks posed by panels are not unlike those posed by dangerous chemicals or materials that release volatile organic compounds on burning.