UK government report investigated 80 solar panel fires in the country
When properly installed, used and maintained, solar cell technology is an incredible solution. Utilising an infinite power source, solar power is helping people make the transition to a cleaner and greener energy source to run their homes, cars and a plethora of devices without sacrificing the standards and comforts of modern-day life.
Recently, media outlets from Japan to Norway have raised questions around fire safety and solar panels. Even when fires occur for reasons unrelated to solar panels, these modules can in fact play a role in both the intensity and speed of a spreading blaze.
A 2018 UK government report, which investigated 80 solar panel fires in the country, found that 58 instances were caused by the photovoltaic system itself. The study notes that some of these fires took place in buildings, while just six occurred on solar farms. In total, these incidents resulted in over a dozen injuries and three fatalities. The report concluded that 38 instances escalated to ‘serious fires’ however only 22 of these were directly caused by the solar panels.
Furthermore, the majority of these fires originated in DC isolators with “the most likely cause of fire as electrical arcing”. Electrical arcing is the electrical breakdown of a gas that produces a prolonged electrical discharge leading to combustion. Effectively, the fire will start by a live wire sending electricity into the air. The temperature of an arc flash can reach several thousands of degrees Celsius.
Renewable technologies carry risks
According to Anders Rørvik Ellingbø, Head of Risk Management Norway at If Insurance, “generally, one expects that purchasing high quality solar panels will mean lower maintenance costs and better overall efficiency. Buying from a reputable brand owner commonly will ensure reliable installation, spare parts availability, user training, as they seek to protect their business, brand and customer base. This can be seen for example in the robustness of cables and components that better withstand regular wear and tear, reducing the probability of failure.”
Buying an expensive system alone will not bring sufficient protection, for example installation plays an important role. From a fire safety perspective, using non-combustible materials between the panels and the roof will help to create a slight buffer, similarly coupling connections need to be covered securely, to keep the fire from escalating quickly.
Anders notes that, “non-combustible plates can mitigate somewhat, but if the fire and temperature accumulate then this is not enough, so we also recommend using non-combustible insulation, (e.g. mineral wool) to help mitigate the spread of fire. This has been proven in tests completed by If Insurance with clients.”
Another recommendation is to install a shut-off switch to disconnect the solar panels from the electrical system. This will not de-electrify the panels, however in case of emergency, shutting off the power will help firefighters manage the fire.
To date, most research in the area of solar panel fires has focused on rooftop installations, with very little research having been done with façade installations. It is important to understand that the challenges are not the same, however.
“Regularly panels are mounted on the roof, where the accumulation of heat radiates back down to the roof, leading quickly to increased temperatures. The role of insulation is also significant here. If the façade features combustible installation, the fire holds a risk of spreading across the entire wall, due to possible chimney effect behind the panels. Use of combustible materials in the vertical construction, i.e. wood, combined with combustible insulation will dramatically increase this risk.”
Industrial scale solar panel installations
From an industrial perspective, businesses are generally very focused on fire safety, adhering to local standards and guidelines. Companies also invest in training their personnel to maintain and use solar cells effectively. Anders explains that, “it is critical to understand the fire safety related issues when making decisions to install extensive energy efficient solutions, many of these technologies are new and with that comes new challenges.”
Globally, China has the largest number of solar power plants, reaching a capacity of some 80GW. This is twice the number of the installed base in the United States.
“Many of the world’s solar panels in use today feature old technology, and this existing installation base is aging quickly. All mechanical equipment deteriorates over time, which means there is an increased fire risk in older panels. For this reason, regular inspections and proper maintenance completed by qualified personnel are important to ensure fire safety,” Anders states.
Simultaneously, building materials are evolving and new technologies are providing smart solutions for businesses and homeowners alike. More research is needed to truly understand these from a fire safety perspective.
“Digital solutions, both in private smart homes or in industrial scale properties also raise some questions. For example, cyber risks include several barriers that must be protected to ensure that these systems are functioning in a reliable and secure way. When extinguishing systems are dependent on sensor technology, the connection between these systems are key components of the smart home or office. There is a risk that these can be hacked or malfunction due to software errors.”
Understanding the risks
Beyond the obvious issues with using water to extinguish electrically charged panels, roof cavities also trap heat. During a large fire event, commonly in commercial and private dwellings, the fire brigade will seek to create openings in the roof to ‘ventilate’ the building. With solar panels installed across the rooftop, it can be more difficult to execute this activity.