Mar 2 2009
Background
What Happens in a Hailstorm
Solar Panel Durability
Solar Array Alignment and How it Protects the Panels
Background
Photovoltaic solar panels produce energy in the form of electricity by using the power of the sun. They were once the restricted to use in extreme circumstances such as for providing power in remote areas or for such exotic applications as satellites and orbiting space stations. As solar panels have become cheaper and climate change concerns have increased, the presence of solar panels on buildings and homes in major cities in becoming increasingly common. One of the primary questions potential purchasers of a solar electricity modules have is what happens to solar panels in a storm, particularly if that storm involves hail.
What Happens in a Hailstorm
Hail stones are super cooled water that forms into irregular shaped balls in storm clouds before falling to earth. Hail tends to be between 5 and 150mm in diameter and the larger stones are normally found in conjunction with severe thunderstorms. Damage caused by hail can be extensive causing the destruction of vehicles, buildings and crops. Concern about hail damage to expensive solar electricity installations is natural, but largely unwarranted.
Solar Panel Durability
Solar panel manufacturers are well aware of the danger hail presents to their product. For this reason solar panels are fitted with a toughened glass surface. The toughened glass in solar panels is typically designed to withstand a direct vertical impact of hail up to 25mm (1 inch) in diameter. Larger hailstones are also unlikely to cause any damage due to the alignment of the solar array.
Solar Array Alignment and How it Protects the Panels
To ensure maximum solar panel efficiency they are aligned to have maximum exposure to the sun. In the northern hemisphere (Europe, North America) this means solar panels are mounted on an angle to face the south. In the southern hemisphere (Australia, Africa, South America) the opposite happens and solar panels face the north. Fortunately severe hail bearing storms tend to approach with northerly winds in the northern hemisphere and southerly winds in the southern hemisphere. The result is that the trajectory of the hail is such that it will hit the back of the solar panel or make a glancing blow only on the front surface of the solar panel.
The result is that even though the solar panel can withstand a direct hit from quite large hail stones, the glancing of hail off the surface of the panels means a much lower impact force. Therefore the solar panels are readily able to escape undamaged from hailstorms that are extremely violent and involve exceptionally large hailstones.
Source: AZoCleantech