Solar Photovoltaic Fire Risks : FE-analysis of fire exposed solar photovoltaic systems and comparison of current legislation and recommendations from different countries

Sammanfattning: The global use of energy increases every day and to meet the growing demand, energy sources are constantly being developed to become more efficient and reliable. During the last decade, the global solar photovoltaics (PV) capacity has increased every year and in 2017, solar PV was the global leading power source of renewable energy. However, hazards and risks regarding fire have been connected to the installation and use of solar PV systems. An Italian study showed an increase of fires in solar PV systems following the increase of installed PV systems. A German report estimated that integrated solar PV systems have 20 times higher fire risk than non-integrated systems. The fire risks of solar PV systems are related to their electrical components, the fact that they produce power as long as a light source is shining and the changed fire dynamic of e.g. roofs when systems are installed. To reduce risks and create standards, several countries have legislated and published recommendations of installation and maintenance of solar PV systems. However, the regulations and recommendations vary greatly between countries and a comparison has therefore been performed in this thesis with the purpose of identifying differences. Legislation and other recommendations from four countries as well as European guidelines have been investigated and compared to see how solar PV systems are regulated. The difference between non-integrated and integrated solar PV systems has been examined as well as the fire risks connected to each system. Furthermore, the impact of solar PV systems during a fire rescue operation have been investigated. Finally, computer simulations have been performed to see what temperatures can be expected at the presence of a solar PV system at a façade.  The result shows a great difference in the level of details in the regulations and recommendations. Some countries have more general requirements while others are very specific in distances between PV systems and fire walls etc. The only requirement found in every countries’ regulations or guidelines is of informative signage. The requirements regarding placement of solar PV systems is also similar between the countries. Such requirements can refer to clear pathways between panels for fire fighter access and distances between modules and smoke/heat exhaust ventilation. The regulations and recommendations found are mostly for non-integrated solar PV system wherefore a suggested further work is to investigate the need for specific regulations regarding integrated systems. Another conclusion is that reports regarding integrated systems are rather common but very few experiments have been performed. A commonly mentioned aspect of fire investigations regarding PV systems is the need for professional planning and installation of the systems. Since the development of solar PV systems is highly increasing, investigations have found that low-quality components and installation faults have led to fires.  The computer simulations were performed using the computer code TASEF with a model representing a wall structure of an integrated PV-system. Two different fire scenarios were investigated where the first scenario represented fire exposure on the solar panel and the other scenario fire exposure within the void (created between the PV and insulation of the wall). The design fires used were the ISO 834-curve and a constant temperature of 800 °C.  The temperatures received in the computer simulation did not vary much between different design fires or the simulated fire scenarios. The highest temperatures were measured in the cavity of the model (between the timber studs and the insulation) and reached between 792 and 937 °C after 60 minutes.  The conclusions of this thesis indicate that the legislation of safety regarding solar PV system is not developing as rapidly as the development of the systems themselves. The difference and specific risks regarding non integrated and integrated PV systems also need to be further investigated, as the current state of the literature is largely unexplored.