TT Talk - Roof-top PV system fire risk

Solar Panel Warehouse Ariel View

With ever increasing focus on the global greenhouse gases emitted into the atmosphere, ports, terminals, warehousing operations, and logistics facilities are striving to decarbonise their operations. As one key option, they are often turning to ‘green’ electricity as a viable energy source to power their activities.

As a familiar energy source and an ever-increasing range of electric powered equipment is made available from the manufacturers to replace their traditionally hydrocarbon-based fuel alternatives, electricity is proving to be the leading fuel source to decarbonise our sector.

The rate of growth in demand for electrical energy from the sector is outstripping the capability of traditional energy suppliers, leading to an increased interest in on-site power generation using wind, hydro and solar, and in some cases backed up with battery energy storage systems (BESS).

Energy transition challenges

Most nations are struggling to satisfy the increasing demands for electrical power that underpin achieving the targets of decarbonisation. The lead-times required to enhance traditional ‘grid’ infrastructure sufficiently to deliver power to industry, including ports and terminals, is encouraging the adoption and scaling of onsite power generation and local/private distribution.

With already a high percentage of renewable energy produced by solar generation and market predictions of continued accelerated growth as shown in Figure 1, and the typically large area of roof-space available from port and terminal warehousing and associated buildings, it is an easy conclusion to draw that roof-top photovoltaic (PV) panels provide a form of power generation that could see significant growth within our sector.

Roof-top photovoltaic (PV) panels provide a form of power generation that could see significant growth within our sector

The deployment of roof-top PV panels is however not without risk and there are numerous examples of fires from these installations. Therefore, there is a need for diligence in their management to i) reduce the risk of fire; ii) limit the impact of fire and iii) support and inform emergency services/first responders with the data they need when tackling a roof-top solar PV fire.

Graph showing solar PV cumulative capacity

Figure 1 - Solar [PV] cumulative capacity forecast [data extracted from statista]

Roof-top PV system fire risk

The probability of roof-top PV systems catching fire is low, but, like other technologies that generate electricity, there is a fire risk. The fire risk can be heightened through;

  • Installation errors or poor workmanship
  • Defects with the system components
  • Water ingress into the electrical components
  • Build-up of dirt, detritus and guano on and around the system components.

In a recent paper published in the Journal of Building Engineering, the authors Mohd et al undertook a fault tree analysis, focusing on the individual components that make up a roof-top PV system, which resulted in an estimated 29 fires per gigawatt [GW] of PV capacity.

Overlaying this estimate of the number of fires per GW with the forecast growth in the PV market as shown in Figure 2 it might be predicted that there could be an increase of 100% in the number of fires over the next three years. This should raise concern, and drive learning and understanding for those asset managers within our sector who already have these systems in place and/or are looking to deploy or scale this method of electricity production.

It might be predicted that there could be an increase of 100% in the number of fires over the next three years

annual solar fire graph

Figure 2 - Estimated PV system fires based on capacity [using data from statista and Mohd et al 2022 research]

Fire fighting challenges

While these types of fire remain rare, the increase in the rate of deployment of this technology demands attention. Typically, firefighters when attending a fire will have limited knowledge of the site prior to responding to an emergency call. Therefore, the asset owner needs to provide vital information regarding the building and the PV system. As a guide this should include:

Building/infrastructure

  • Location and pressure of fire hydrants
  • Roof construction, which should include location of any fragile and combustible material
  • Access locations and means of access/egress
  • Contents of the building and any specific fire risks

PV System

  • PV system layout
  • PV system details, such as the type, age and any safety systems that are in place

Asset management for PV systems

As with most assets, the importance of having a well thought-out and regularly reviewed asset management plan is a key factor in maintaining safety and efficiency. This is especially the case when managing PV systems, including:

  • Local regulations for the system should be understood and asset management plans for the building on which the system is installed should be updated accordingly
  • Preventative maintenance, carried out by suitably qualified and experienced engineers should be conducted in line with the OEM’s recommendations. This should include, but not limited to, inspection of the components and associated cleaning
  • Corrective maintenance should done by suitably qualified and experienced engineers, in line with the OEM’s recommendations and using replacement components which are verified as compatible with the installed system.

Key takeaways

  • Roof-top PV systems introduce a potential fire risk to a building that previously was not there. Therefore, a new fire risk assessment for the building will be required to account for this change and details of the PV system made available for firefighters
  • The necessary location of these systems on top of buildings, and therefore out of sight, can lead to fires going undetected until they are well established
  • There is potential for the system to continue generating electricity during a fire; this should be considered during any firefighting and understood by the firefighters
  • Consideration should be given to the insured value of the building since PV systems may add significantly to the cost of any reparation claim.

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If you would like further information, or have any comments, please email us, or take this opportunity to forward to any others who you may feel would be interested.

Neil Dalus

TT Club

Date04/06/2024