Battery Energy Storage Systems (BESS) Frequently Asked Questions (FAQ’s) on Fire Safety

Are BESS facilities safe?

The BESS industry is undergoing rapid growth and development. Lithium-ion batteries, commonly used in mobile phones and electric cars, are currently the dominant storage technology for large scale BESS facilities. Concerns have been raised regarding the safety of BESS facilities because lithium-ion batteries contain flammable electrolytes that, if overheated, can short circuit and catch fire, also known as “thermal runaway”. This type of fire can be difficult to extinguish and BESS infrastructure costly to replace. Reducing risk of fire is therefore an important consideration for both municipalities and project developers. Technology is consistently being improved with safety features to address these concerns, including cooling systems and real time temperature monitoring.

Who sets the fire safety requirements for BESS?

From a BESS permitting and approval standpoint, the process outlined in Hydro One’s BESS Fire Protection Risk & Response Assessment Standard (FPRRAS) is comprehensive. The Standard was specifically developed to address BESS in proximity to Hydro One’s transmission facilities. All BESS proponents are required to provide a self-certification per Appendix-1 of the FPRRAS stating that they have carried out the assessments and that the facility poses no safety or outage risk or unmitigated hazard to Hydro One employees and Hydro One’s transmission system. This self-certification is to be submitted to Hydro One during the commissioning of BESS facility prior to connecting to the Hydro One owned transmission system.

The following are assessments are listed under Appendix 1:

  1. Hazard Mitigation Analysis, including UL 9540 Listing, UL9540A Test Reports, Fault Condition Assessment

  1. Fisk Risk Assessment, including Community Risk Assessment and Air/Gas Dispersion Study

  1. Fire Protection Design Documentation, Including Passive Fire Protection Systems and Active Fire Protection Systems

  1. Commissioning Plan

  1. Decommissioning Plan

  1. Emergency Response Plan including Fire Department Training.

How do third party standards apply to the BESS projects in Ottawa?

The primary authority for the Installation and Approval of Energy Storage Systems connected to the electrical grid in Ontario is the Electrical Safety Authority (ESA). The ESA administers Part VIII of the Electricity Act and oversees the Ontario Electrical Safety Code (OESC). Inspections under the OSC would be ongoing during construction with the final inspection completed prior to energization. The electrical permitting process does not include specific BESS requirements.

NFPA 855

The National Fire Protection Association is an international non-profit organization that promotes safety standards, education, and training on fire and electrical-related hazards. NFPA 855 is the Standard for the Installation of Stationary Energy Storage Systems, which serves as a guideline for Canadian fire departments. The standard outlines processes for training, pre-incident planning, hazard mitigation analysis, testing, decommissioning, and post-incident handover procedures to energy storage system owner. Conditions set in NFPA 855 are required according to the Hydro One Standard - Section 5.0 Minimum Design Documentation, specifically in the Hazard Mitigation Analysis (which includes the Fault Condition Assessment). However, mandatory permitting and inspections are set by Hydro One Standard (not NFPA 855).

UL9540

UL 9540 is the North American safety standard for energy storage systems, which was developed by Underwriters Laboratories (UL). Both the American National Standards Institute (ANSI) and the Standards Council of Canada (SCC) have approved UL 9540. OESC mandates UL 9540 certification, so this would be regulated in the electrical safety code. Hydro One Standard also requires proof of compliance with UL 9540.

UL9540A

UL 9540A is a method for evaluating “thermal runaway” and sets out requirements for battery management systems (BMS) including battery safety, performance and communications protocols. This standard was developed to verify the effectiveness of protection levels against thermal runaway and fire hazards. The OESC mandates UL 9540A certification so this would be regulated in the electrical safety code. The Hydro One Standard also requires proof of compliance with UL 9540A.

How will Ottawa Fire Services respond to a fire incident involving a BESS system?

Ottawa Fire Services (OFS) develops emergency response plans based upon the occupancy and hazards specific to each location, creating standardized response protocols that address these needs. Prevention through early detection and suppression mitigation is our primary response. In the rare event of a fire emergency, OFS’ tactical priorities are focused on addressing any threat to life, reducing property loss, and mitigating environmental impacts. Fire suppression efforts will centre on preventing the spread of fire, with specialized air monitoring conducted throughout the event.

Is water to be used to respond to a fire incident involving a BESS system?

Automated prevention and suppression systems aim to mitigate the potential for a fire. In the event of a fire, fire tactics will primarily focus on protecting exposures to prevent the spread of flames. Each site will be assessed on a case-by-case basis to determine the appropriate water supply requirements, which may include municipal water supply, on-site storage reservoirs, or the installation of dry or remote hydrant systems.

Is there a risk of groundwater contamination due to run off if water is used to respond to a BESS fire?

The risk of groundwater contamination from firefighting water runoff during a BESS fire is estimated to be minimal. Most contaminants will burn off, with safety monitored throughout the event, and appropriate actions taken to protect the public if necessary. As with similar incidents involving the risk of contaminated liquids reaching the soil, the situation will be evaluated, and a cleanup service will be secured if needed. These considerations will also be factored into the site plan approval process, with a focus on prevention and mitigation strategies to further minimize environmental risks.

Will residents be able to be informed of the details related to a fire incident associated with a BESS, such as whether there was a risk of air or groundwater contamination?

OFS will have specialized teams conducting air monitoring throughout the event. If there is a risk of air contamination, it will be assessed and communicated during the incident, with updates provided as needed. Typically, the risk of air contamination is mitigated shortly after the fire is extinguished. Ongoing air monitoring and groundwater testing will be included as a condition of the approval process to ensure comprehensive environmental protection after the event.

Will Ottawa Fire Services inspect and certify that BESS projects are safe before they operational?

OFS plays a role in ensuring the safety of BESS projects. While the certification of the BESS unit itself is managed by external experts to ensure compliance with standards like NFPA 855, OFS’ focus is providing specialized expertise in firefighting capabilities, hazard mitigation and emergency response. OFS participates in the overall design review, which includes evaluating site access, layout, firefighting requirements, and the emergency response plan.

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