TNO-led group analyzes building fires associated with solar panels

04 Dec 2024

Of 10,000 fires in 2022-23, 152 involved buildings fitted with solar energy systems (fewer than 2%).

Netherlands-based research institutes TNO, Institute for Public Safety (NIPV), and the Standardization Institute (NEN), have mapped out for the first time how many building fires in the Netherlands between 2022 and 2023 involved a solar energy system.

Of 10,000 building fires during this period, 152 cases involved buildings equipped with solar energy systems (fewer than 2%). Although the three organizations are satisfied with this initial knowledge base, they emphasized the need to collect data over a longer period before drawing conclusions.

In recent years, the number of solar panel installations on buildings has increased significantly, the report noted. With the growing popularity of solar energy systems, concerns about fire risks have also risen. However, the report stated, “it is challenging to determine whether the solar panels were the cause of a fire and under what circumstances the fire started.”

Until 2023, building fires involving solar energy systems were not systematically recorded. This study provides a foundation for gaining more insight into building fires with solar energy systems and developing a test method for understanding the impact of these systems on roofs.

Of the 152 fires that involved buildings equipped with solar energy systems, 70 could be further investigated with the help of the Fire Investigation Teams of the safety regions. The research reveals that – in these 70 cases – the cause of the fire was almost as often related to the solar energy system as it was not: in 30 fires, it was established that the fire originated in the solar energy system. In 29 cases, it was known that the system was not the cause, and in 11 cases, the cause was unknown.

Researchers from the three institutes emphasised that various developments will influence potential fire incidents in the coming years. The report states, “For example, the first generation of solar panels is now reaching the end of their lifespan and may be less safe. Additionally, the enormous demand for solar energy systems has led to an increase in installation companies, some of which do not fully comply with standards.”

This research is described as “a first step towards establishing a knowledge base but contains limited data.” Only fires where the fire department intervened and where information could be obtained through the Fire Investigation Teams of the safety regions were included. Additionally, it was not possible to use data from insurance companies. To gain better insight into the extent of fire risks, the organizations advocate for financial resources to better monitor and analyze fire incidents over the next four years.

In this research, commissioned by the Netherlands Ministry of Climate & Green Growth, NIPV set up the national database for building fires and collected data. TNO had a coordinating role and contributed to data collection and analysis of fires. Furthermore, NEN contributed by conducting various fire tests and developing a European test method.

In relation to the above photograph of a fire on a building equipped with solar panels, the report states: “The panels next to the roof extension were also involved in the fire. The orientation of the roof is almost due south. This means that the panels that lie tightly against the roof extension will soon have shade in the afternoon. [Considering the bottom panel…] In this panel, the bypass diodes will often be in conduction and become hot. This can cause accelerated ageing of the materials in the panel with a possible increased risk of short circuit.”

To View the full report (in Dutch), visit the website Final report on improving fire safety monitoring and regulations.