Per a conversation between pv magazine USA, and the National Fire Data Center, there is no information available on the number of fires from solar power systems, rooftop or ground. The group says, that they don’t have a code for it yet so they don’t track it, meaning these events end up in a very large “other” category. The National Fire Protection Association does have a solar photovoltaics safety related page.
I’ve got a feeling there are some who definitely don’t consider this an “other” type of event.
In 2013, a warehouse in Delanco, New Jersey burnt to the ground. While there were issues with water supply at the site, firefighters were also unsure how to act due to 7,000 solar panels on the roof. This event was part of the logic that led to today’s National Electric Code requirements for module level automatic shutdown requirements, to protect first responders against the risk of electricity flow even if main electrical switches to the site have been shut down.
The Japanese Consumer Safety Investigation Commission recently reported on 127 rooftop solar problems, “including fires”, that occurred over a ten year period ending in November of 2017. Of those, thirteen led to fires from a modules or cable, and seven of those spread to the roof – but all seven included modules directly attached to the structure (solar shingles?). As of October 2018, there were 2.4 million homes with rooftop solar in Japan.
Research by German group Fraunhofer ISE noted there were greater than 1.4 million solar power installations in the country. As of the date of publication, February 1, 2019, and going back 20 years, approximately 350 solar power systems – 0.006% per Fraunhofer – have caught fire. It was found that the solar system was at fault in 120 of those cases, with damage being severe in 75 cases – and complete building loss occurring in ten cases.
Considering the US has about 2 million solar systems installed, the data above is quite comparable.
National Renewable Energy Lab (NREL) looked at global solar power related fire standards and – above image – noted the challenges to be dealt with.
Most research notes that the equipment failures are even rarer than the fires themselves. Tightening connections is the number one challenge as loose connections can lead to sparks flying, which set nearby items on fire.
This general idea aligned with analysis on energy storage fires in South Korea, who found that in 23 events all of them were related to installation and design versus equipment. As well, the Walmart vs Tesla event mostly talked about the quality of contract work versus hardware, though solar modules with hotspots were noted.
And though it wasn’t a rooftop system, we did recently had fire when a bird “flew into a pair of wires, creating an electric circuit and a shower of sparks” and setting 1,127 acre fire that caused $8-9 million in damage at a 250 MW solar power plant, temporarily shutting down 84% of the facility.