Photovoltaic systems are different from traditional electrical installations, but not more dangerous, concluded industry experts at a recent fire protection workshop held in Germany.
The workshop, led by Fraunhofer Institute for Solar Energy Systems ISE and TUV Rheinland in Freiburg, Germany, featured 120 participants, including manufacturers, researchers, representatives from the fire brigade, and insurance companies.
All of the parties agreed that the best fire protection is the adherence to existing regulations through the use of qualified, skilled workers.
‘Every fire is one too many,’ said Dr. Heribert Schmidt, project leader at Fraunhofer ISE, in the report issued after the workshop. ‘However, if one takes a look at the statistics, then 0.006 percent of the photovoltaic systems caused a fire resulting in large damage.’
Due to the high number of PV systems in Germany, the global solar sector can draw valuable fire-safety lessons from the country's installation base and their implications on fire safety.
Currently, there are 1.3 million PV systems in Germany, and over the last 20 years, there were 350 fires in which photovoltaic systems were involved, according to Fraunhofer ISE. In 120 of these cases, the photovoltaic system was the cause of the fire.
In 75 cases, the damage was considered extensive, and in 10 cases, the entire building was burned to the ground.
Since February 2011, experts in Germany have been working on a project – sponsored by the German Federal Ministry for the Environment – to analyze the fire risks of photovoltaic systems and determine whether the existing standards and safety concepts should be supplemented.
Risk factors
The most important characteristic of photovoltaic systems is that they produce direct current. One cannot simply switch the power off, as the system continues to generate electricity as long as sunlight is incident on the modules.
For example, if a low-quality or poorly installed module connector loosens, the current flow is not always interrupted. An electric arc may occur, which, in the worst-case scenario, can directly start a fire. Accordingly, investigations are being carried out on how to prohibit the occurrence of electric arcs.
In addition, detectors are being developed that sound an alarm as soon as a small electric arc occurs. Overall, however, representatives from insurance companies, technicians and Germany's fire brigade have agreed that, compared to other technical systems, photovoltaic systems do not present a higher fire risk, Fraunhofer ISE says.
With comprehensive training courses for the fire brigade, any preliminary uncertainties can be eased. As with every electrical installation, fire personnel can also extinguish a fire using water from a distance of one to five meters, depending on the type of electric arc.
Based on the investigations to date, all claims stating that the fire brigade could not extinguish a house fire because of the photovoltaic system have been shown to be false.
The industry stakeholders concluded that there are sufficient codes in place that ensure the electrical safety for photovoltaic systems, but the key is ensuring adherence to those codes.
Fires often start when inexperienced installation crews install the system, according to Fraunhofer ISE. For instance, when solar module connectors are installed using combination pliers instead of special tools designed for this purpose, or when incompatible connectors are used, the vulnerability of the system increases.
Therefore, in addition to technical improvements, Fraunhofer ISE and other parties in Germany plan to investigate additional regulations to ensure that codes are being followed.
Currently, a system installer itself is allowed to provide the confirmation that its installation was carried out according to the rules. One recommendation from the experts, therefore, is to require that the acceptance test be performed by a third party.
Another possibility is to require regular safety tests for privately owned systems. Commercial systems are already required to be inspected every four years.
