Solar Panels

 

 

Photovoltaic (PV) solar panels are now ubiquitous. Through carrot and stick methods, Governments have incentivised and compelled populations to embrace this technology. Grants, and tax reliefs have helped encourage and proliferate the development and growth of the market; while Building Regulation requirements have steadily increased the minimum standards in conservation of fuel and energy (refer to Technical Guidance Document (TGD) Part L). Consequently, sometimes the easiest thing for a designer to do is include solar panels in the design to meet the minimum requirements, along with other conservation approaches, such as increased insulation provision.

Like everything else, the technology has its benefits and its challenges. 

Below are some risks I discovered in relation to solar panel installations, which you may find interesting. I would encourage you to add to this conversation in the comments. This is not a comprehensive or exhaustive list:


Fire to PV installations.

This has become a more common occurrence.

- Brussels blaze points to growing risk of fires caused by solar panels (25/10/2024) - David Rogers, Global Construction Review, available at https://www.globalconstructionreview.com/brussels-blaze-points-to-growing-risk-of-fires-caused-by-solar-panels/
- A fire destroyed hundreds of solar panels at an Amazon warehouse in Fresno in 2020 (29/09/2022) - KMPH FOX26 NEWS, available at https://www.youtube.com/watch?v=1tay5dhaLgU
- Solar panel fire at Sydney Olympic Park Aquatic Centre (13/05/2024), NSW Government, available at https://www.fire.nsw.gov.au/incident.php?record=receaW2T9Pzv4kd1I
- Warehouse fire raises possible problems with solar panels (25/07/2023), 6abc Philadelphia, available at https://www.youtube.com/watch?v=DgSDyhlug_c

The BRE National Solar Centre published “Fire and Solar PV Systems – Investigations and Evidence” in 2018, and in this report, they identified some of the factors as being electrical arcing likely caused by:
- “Moisture ingress degrading connections in connectors, junction boxes and switches
- Incorrectly crimped connector contacts
- The mating of incompatible plugs and sockets
- Plugs and sockets not fully engaged.
- Loose screw terminals within junction boxes or isolator switches
- Poorly soldered joints within a PV module junction box or other junction box defect
- Damage to a component (e.g. broken busbar within a PV module).”

Other mechanisms for starting fires identified, included:
- resistive heating (alone) can be the cause of fires, but less likely, and a potential precursor to arcing.
- Breakdown of electronic components, such as capacitors or transformers, is possible and these are thought to be likely causes of fires in inverters. However, the statistics collected do not highlight inverters as a common origin of fires.

I note that when fires occur, the fire can be exacerbated by the proximity of combustible materials, such as roofing membranes, and the plastic covering on the solar panels. The BRE report, refers to the storage of flammable items in lofts, and the actual roof timbers as vectors of fire.


Hot Spots, on solar PV Modules

Hot spots are an interesting phenomenon, where localised overheating can occur, where “…the short circuit current of the affected cell becomes lower than the operating current of the whole, giving rise to reverse biasing…” (Experimental observations on hot-spots and derived acceptance/rejection criteria). The previously referenced report notes that causes can be external to the solar panels, or internal defects, and include:
- Shading
- Dust
- micro-cracks
- defective soldering
- potential induced degradation
- material imperfections

Standing water on a flat panel, could also cause uneven energy production, similar to partial shading (https://www.youtube.com/shorts/XRSWS_pblds). 

A Youtuber with a channel called The Drone Life, has some excellent photographs of the type of issues that can occur:

 - Drone exposes hidden danger on solar panels (https://www.youtube.com/shorts/nRbj-hE7iQI)
 - Every solar designer's worst nightmare! (https://www.youtube.com/shorts/UnMf7oQULOA)

How does this affect the solar panel installation?

- Inefficient energy production.
- Degradation of materials, including silicone, connectors, and encapsulants, leading to permanent damage.
- Given the potential for short circuiting, and arcing over time, possible increased risk of fire.


Takeaways

Solar panels are an amazing technology. There are risks associated with them, and I note the following mitigating measures I would consider:
- Use a competent and insured designer to design and specify the installation, ensuring compliance with all legal and regulatory requirements, and that the panels received are of good quality.
- Designing the location, and method of installation to mitigate against issues such as standing water, shading and partial shading, bird damage and nesting (bird spikes or nets?), etc.
- Consider the proximity of flammable materials during design and consult a competent and insured fire engineer.
- Use a competent and insured contractor to install, commission, and handover the installation in accordance with designer requirements, manufacturer’s requirements, and legal and regulatory requirements.
- Ensure an operation and maintenance manual is received for the installations.
- Ensure all materials comply with CE marking of the European directive (Regulation (EU) No 305/2011).
- Protect solar panels and equipment from damage during transport, delivery, storage on site, etc.
- Consider excessive storage of materials in lofts, and other voids in proximity to the solar panels and associated electrical installations.
- Undertake regular inspection, cleaning, and maintenance by competent and insured contractors in accordance with manufacturer requirements, and the operation and maintenance manual. Consider regular thermographic (infrared camera) inspection surveys of installations to identify hot spots and determine the associated causes (external or internal), and remedies (relocation, replacement, cleaning, etc.) by a competent and insured Contractor.
- In the event of a fire, consider how;

o the fire will be detected (fire detection and alarms in roof void, or other close proximity, and in compliance with Building Regulations and IS3218),
o building/s will be evacuated, and
o Fire services will make the installation safe (Fireman’s Switch to isolate the solar panels, etc.), access and tackle the fire in a safe and expedient manner.

Limit of liability/Disclaimer of Warranty: This post is not professional advice of any kind. The Author makes no representations or warranties with respect to the accuracy or completeness of the contents of this blog post and specifically disclaim any implied warranties of merchantability or fitness for purpose. You should consult with a competent and insured professional where appropriate. The author shall not be liable for damages arising herefrom.