Students’ Corner – Photovoltaic Panels: Great for the environment, but at what cost?

Posted: June 18, 2015 in Fire Investigation, Fire Protection, Fire Science
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by: Sara Caton

Sustainability, green technology, and clean energy are all trends that are found at the forefront of engineering and design in today’s world. Because of society’s focus on sustainability, photovoltaic (PV) panels, which use sunlight to generate electricity, are increasingly popular renewable energy systems. In 2013, PV installations in the twenty-four countries that make up the International Energy Agency (IEA) Photovoltaic Power Systems (PVPS) Program combined with non-IEA PVPS countries totaled approximately thirty-nine to forty gigawatts. This total is the highest installation value ever for PV, with a growth of about 35%. (Photovoltaic Power Systems Program, 2014) Although the installation of PV systems increased in 2013, the total investments in renewable energy actually decreased. This can be attributed to the cost reductions of solar PV installations. (Global Trends in Renewable Energy Investment, 2014) The IEA PVPS Program findings and the decreased installation costs emphasize that the use of PV panel systems is a global trend that will continue to grow.

I am completely on board with these PV installation trends, because I believe it is an easy way for people to incorporate the use of solar energy in their lives. PV systems provide great benefits to the environment, which is why the installation of them is so popular; however, these systems can pose great dangers and threats, especially during a fire event. A building that has a PV system installed on the roof may experience increased building loss during a fire compared to a building without a PV system, and the emergency responders are faced with new and different dangers during a structure fire that has a PV panel system. These are concerns that fire protection engineers need to be aware of in order to better protect buildings and people from fires that involve buildings with PV installations.

Lessons can be learned from fire incidents that involve PV panel systems. A fire occurred in a chemical manufacturing facility in West Berlin, NJ that, according to officials, was caused by propane tanks igniting and causing multiple small explosions inside the facility. (Glover, 2014) Dozens of rows of PV panels were installed on the roof of the building, making matters worse. When water was sprayed onto the roof from above, it collapsed. “Firefighters were forced to knock down an outer wall of the facility to expose the collapsed solar panels as well as to fight flare-ups.” (Glover, 2014)

From this example, it is illustrated that building loss and damages can be severely increased during a fire in a structure that has a PV system installed on the roof. The PV system adds a dead load to the roof and can be affected by other external loads caused by the elements. These added loads could be part of the reason the roof was not able to withstand the water jets. Since the PV panels posed an electrocution threat to the firefighters, they had to find alternative options to approaching the fire, which resulted in this example by taking down an exterior wall. This action also increased the amount of damage to the building.

I think it is important to investigate and ask questions about fire incidents that involve PV panel systems to learn how to avoid these dangerous fires and how to protect the emergency responders from these new threats. The two main dangers that these fire pose to emergency responders are electric shock due to direct contact with energized components and electric shock from water-based fire suppression. If energized components are exposed because the protective covering of the panels break due to the fire or fire fighting techniques, the fire fighter can receive an electric shock from direct contact. Because it is impossible to fully de-energize the components of the PV systems and water is conductive, using water for suppression without the threat of electric shock becomes difficult.

There has been research done that suggests safe distances for water application and nozzle spray types, appropriate insulated gloves for firefighters, and the use of tarps to help de-energize PV components. In my personal opinion, more research needs to be done to develop adequately safe fire boots that will help the firefighters avoid electric shock. The table below shows that tests conducted at UL found that aged boots do not perform well in response to shock. Firefighters’ boots generally have conductive metal toe and sole plates to protect the foot, but this conductivity can be a danger when dealing with energized electrical components (Backstrom, 2011). In order to not negate the benefits PV systems provide for the environment, it is vital for fire protection engineers to ensure the safety of firefighters who may be faced with fighting PV system fire incidents.

References

Backstrom, 2011: Robert Backstrom and David Dini, Fire fighter Safety and Photovoltaic Installations Research Project, Underwriters Laboratories, Inc., November 29.

Global Trends in Renewable Energy Investment, 2014: Global Trends in Renewable Energy Investment, Frankfurt School of Finance and Management, 2014.

Glover, 2014: Sarah Glover and Vince Lattanzio, “Fire Destroys NJ Chemical Manufacturer’s Facility,” NBC News, May, 2014.

Photovoltaic Power Systems Program, 2014: Photovoltaic Power Systems Program, “Trends in Photovoltaic Application 2014,” International Energy Agency, 2014.

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