There are over 1.5 million electricity generating, photovoltaic solar systems in Germany – many are rooftop models. Given the current flood situation in different regions in Germany, TÜV Rheinland experts would like to caution the public about risks to solar systems during floods.
Safety precautions for photovoltaic solar systems in flooded regions
Even if the power supply is turned off, systems with inverters and connection to the regional electricity grid present a risk of electric shock or gas explosion, if they are in areas of the house that are flooded. “For systems in a basement that has become flooded and which might still be under electrical current – the area may not be entered. Never go near systems that are underwater, because they are automatically energized when light strikes the rooftop panels. An exception is plants that can be shut down via a separate switch, which is located in a non-flooded area,” warns TÜV Rheinland expert, Willi Vaaßen. Power companies turn off the power in floods, however cables and connection points between the photovoltaic panels on the roof of the house and the inverter can remain energized.
Furthermore, if an inverter is in a small, enclosed storage space or room, which is underwater for a long time, depending on the amount of sunlight that strikes the panels, electrical current can flow through the water able to induce electrolytic processes, whereby the water is split into hydrogen and oxygen. In rooms where oxygen collects there is a higher risk of explosion, if ignition comes into play. Therefore, during flood clean-up, fire must be strictly avoided and the premises should be well ventilated.
Primary action: disconnection
The general recommendation from TÜV Rheinland experts is that generators be disconnected by certified electricians. When the water recedes, solar systems should first be checked by trained electricians, ideally those from the company which built the facility, therefore limiting hazards and ensuring expert shut down, until the systems can be drained and checked for damage.
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