Solar panels, also known as photovoltaic (PV) panels, are globally one of the fastest growing forms of generating electricity. Whilst providing an important form of renewable energy, it is worth noting that, like any other electrical system, there is a risk of fire.
This advice and guidance article covers solar panels as a fire hazard, covering what solar panels are, how they work, how they can catch fire, and what causes them to catch fire.
What are solar panels?
Solar panels are a form of renewable energy that captures the solar radiation of the sun and converts it into electricity.
PV systems can be:
- mounted on rooftops, from single dwellings, to larger warehouse/shed-type buildings, providing electricity for homes and business applications, often with potential to export additional power;
- expansive ground-mounted PV installations, providing significant electrical power into the power grid.
This article focuses on the former.
How do solar panels work?
A photovoltaic system is made up of several components that convert sunlight into electricity. PV panels make up the main bulk of the system, and typically each panel covers an area of 1.7-2.5m2, depending on the manufacturer.
DC (direct current) produced by PV panels is converted to AC (alternating current) using inverters, for local use or to be sent to power grids. In addition to this, many systems will include a battery energy storage system (BESS) that provides storage of power for use when the sun is not shining. The diagram below shows a photovoltaic system integrated with battery energy storage.
The solar cells themselves are made up of a thin layer of semi-conducting material between a sheet of glass and a polymer resin/glass backing. When exposed to daylight, the semi-conducting material produces electricity through what is known as the “photovoltaic effect”. The following diagram shows the makeup of a solar panel:
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Can solar panels catch fire?
Whilst the risk of solar panel systems catching fire is extremely low, like any other technology that produces electricity, they can catch fire. In 2023, an article published by The Independent revealed that from January-July 2023, 66 fires relating to solar panels had occurred in the UK, compared to the 63 fires that were reported for the whole of 2019.
The growing number of solar-panel related fires reflects the growing reliance on solar as an energy source amidst the cost-of-living crisis, so it is important to understand what causes solar panel fires and some ways we can mitigate this to reduce the risk.
What causes solar panels to catch fire?
There are several reasons why a solar panel may catch fire. One of the main causes of solar panel malfunctions are solar panel installation faults. Not using a competent installer of solar PV systems can lead to faults with potential to cause fires. Similarly, product defects make up a significant portion of solar-related fires, in which poor quality or incompatible components add to the risk of fire.
Planning and design issues can also add to the risk of solar panel fires, causing damage to not just the PV installation, but the building on which they are mounted. An example of this would be a PV system being installed on a combustible/partially combustible roof, with no fire-resistant covering. Finally, external influences also make up a portion of solar panel fires.
External influences that can cause solar panel fires include moisture and water ingress into parts of the PV system, such as the DC and AC connectors. Additionally, consideration should be given to things such as build-up of dirt, bird droppings, and foliage on PV panels. These can lead to shading, causing hot spots that can escalate to burning.
Photovoltaic system risk control measures
There are several actions you can take when it comes to minimising the risk of fire with solar panels. These include, but are not limited to:
- Carrying out a suitable fire risk assessment.
- Undertaking a full consultation with the building owner and insurer.
- Install solar panels with a certified and competent professional.
- Design and install PV systems in accordance with the IET PV Code of Practice and MCS requirements. MCS (Microgeneration Certification Scheme) create and maintains the standards for small-scale renewable technologies and the contractors who install them.
- Ensure roof materials are non-combustible, and where applicable, apply a fire-resistant covering.
- Implement a system whereby solar panels are regularly cleaned by a suitably trained person, paying particular attention to bird droppings and the build-up of litter and leaves around or beneath PV panels.
- Ensure that sufficient protection measures for the prevention of theft and vandalism are provided. RISCAuthority document S33 Solar Farm Security provides useful information on this topic.
A full list of recommendations for risk control measures of photovoltaic systems are available in RC62: Recommendations for fire safety with PV panel installations, 2023.
Additional resources
You can find a range of helpful resources concerning solar panels here:
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Please be aware that considerable efforts have been made to ensure the accuracy of the information contained within this article at the time of publication, however any legislative (or other) changes that come into effect after this may render the information out of date until it is reviewed and updated as part of the FPA’s content review cycle.