Wind turbines, solar, hydropower, geothermal energy, these are only some examples of renewable energy sources. Unfortunately, the business of storing energy can be incredibly dangerous. So much so that in 2020 the National Fire Protection Association developed NFPA 855 – Standard for the Installation of Stationary Energy Storage Systems.
Devising a way to safely store renewable energy for later use is essential for attaining a greener future. This article will touch on basic safety measures every ESS facility must take. That said, this article is not to be used as a replacement for the printed standard, but rather a resource to accompany it.
What are Energy Storage Systems?
While there are many ways to generate electricity, there are only a handful of ways to store it for later. Stationary energy storage systems usually refer to structures that house large batteries (connected to a renewable energy source), an electronic control system, inverter, and thermal management system. These components are all in one enclosure either outside or within a building.
These large batteries must then be charged to provide electricity to the grid or for the facility utilizing the power. There are a handful of different storage systems being developed for this purpose, these include:
- Compressed air energy storage – Excess energy is used to compress air and store it, to eventually release it for the purpose of turning a turbine which generates electricity.
- Mechanical gravity energy storage – Electricity is generated by the pull of gravity through lifting and lowering objects.
- Flow batteries for energy storage – Chemical energy is used to create rechargeable fuel cells. Think of lead batteries or lithium-ion batteries.
NFPA 855: Essential Fire Code RequirementsThe following is by no means the complete list of regulations that facilities must comply with. Instead, it includes some of the most important best practice methods that facilities must remember if a stationary energy storage system is present. That said, it is the employer’s responsibility to become familiar with NFPA 855. It can be found on the NFPA’s website for free since it is technically a voluntary standard.
The first rule that we will touch on is 4.1.1 ESS Gas Release. The NFPA standard directly states, “ESS shall not release toxic or highly toxic gas creating conditions in excess of the permissible exposure limit (PEL) in the room or space in which they are located during normal charging, discharging, and use.”
One of the biggest concerns of ESS, particularly with lithium-ion batteries, is what is called thermal runaway. These batteries create quite a bit of heat, which requires a sufficient cooling system to control the temperature of the ESS. However, if it gets out of control, the lithium battery can begin to spew toxic gases and even explode.
The list of permissible exposure limits can be found on OSHA’s website. These numbers should also be present on safety data sheets for the company’s records. Not only will it help employees identify when to use the right PPE, but SDSs also help first responders if the situation escalates to an emergency.
Next, the facility must have aplan for installation and maintenance for the ESS.NFPA 855 states in 188.8.131.52.1 General,“The plans and specifications associated with an ESS and its intended installation, replacement, or renewal, commissioning, and use shall be submitted to the AHJ for approval.”
This installation plan must include the following pieces of information:
- A diagram of the location and layout of the area where the ESS will be installed
- Hourly details on the necessary fire-resistant-rated assemblies provided for the ESS
- The types of ESS units present and the quantity
- Manufacturer’s specification, rating, and listings of the ESS
- A description of the energy storage management systems in use and how they operate
- The location and content of necessary visual communication
- Details pertaining to fire suppression, smoke or fire detection, gas detection, thermal management, ventilation, exhaust, and deflagration venting systems, if used with the ESS
- Information on support arrangement pertaining to the installation. This includes any required seismic support
Give employees, managers, and emergency personnel the information they need to both operate this dangerous equipment safely and prevent emergency situations.
Emergency Operation Plan Requirements
Emergency protocol in the past for ESS has been sparse. Take for example the tragic incident at an energy storage system facility in Surprise, Arizona. In 2019, a massive explosion almost killed four firefighters when they went to respond to an emergency involving thermal runaway of lithium-ion batteries. There were no SDSs, the utility and battery maker had a limited response plan, and the staff were incorrect about the gas used for fire suppression. Missing information is never ok in dangerous environments.
The following are the necessary requirements for an emergency operations plan dealing with ESS. If followed correctly, the facility can hope to prevent serious injuries and death when it comes to emergency response:
- Define procedures for safe shutdown, de-energizing, or isolation of equipment in emergency situations. This will reduce the risk of fire, electric shock, and personal injuries
- Define the safe start-up protocol after emergency conditions have passed
- Define the procedures for inspection and testing of ESS related alarms, interlocks, and controls
- Explain the procedures to be followed upon being notified of dangerous conditions, including shutting down equipment, summoning service and repair personnel, and providing notification to the fire department of potentially hazardous conditions
- Define the emergency procedures to be followed in case of fire, explosion, release of liquids or vapors, damage to critical moving parts, or other dangerous conditions
- The presence of safety data sheets that will address safety concerns and extinguishment when needed
- Procedures for dealing with ESS equipment damaged in a fire or other emergency event, as well as any contact information for qualified personnel that can safety remove damaged ESS equipment
- Other procedures as determined necessary by the AHJ
- How and when to perform drills of these emergency procedures
This is the basic checklist that you can use to establish an emergency plan for the ESS in your facility. That said, you may add any extra protocol you deem necessary for the safety of both the facility’s workers and emergency responders.
Training employees on Standard 855
Emergency planning and training must be provided by the ESS owner so operations, maintenance, and emergency responders can address any potential hazards in a safe manner.
Just like many other emergency training and fire protection training programs out there, ESS training should be completed annually at a minimum. There also must be records of completed training courses for employees.
Aside from drill and class time, there must also be manuals at the ready for reference. Described in 184.108.40.206 Manuals of the NFPA 855 standard, “an operations and maintenance manual shall be provided to both the ESS owner or their authorized agent and system operator before the system is put into operation.”
That manual must include the following information:
- The size of the ESS and options for each component of the system
- The manufacturer’s operation and maintenance manuals for the entire energy storage system
- The contracted service agency’s contact information or those within the building that are responsible for the ESS
- The recommended operational set points as well as the scope of what the ESS system is used for
- A service record log
Combined, both regular training and reference texts are essential for ESS safety.
What About Labels?
Proper energy storage system safety always includes the addition of appropriate danger, warning, and caution labels. Visual communication such as labels and floor markings remind employees of essential protocol like wearing PPE or prohibiting certain unsafe behavior.
The NFPA 855 standard has the following requirements for ESS labeling:
- Signs must be present on doors or next to entryways where ESS equipment is kept
- Signage must be on the front of doors to outdoor ESS containers
- Signs must be present in approved locations on outdoor ESS that are not enclosed in occupiable containers or otherwise enclosed
Now that we know where they go, the design specifications must be outlined. ESS labels and signs must follow ANSI Z535 color and design standards as well as include:
- The phrase “Energy Storage Systems” with the symbol of a lightning bolt in a triangle
- The type of tech associated with the ESS
- Any special hazards
- The type of suppression system installed
- The necessary emergency contact info
A permanent plaque or directory must be used to mark all the disconnecting means of power sources as well.
While ESS systems are dangerous, they can be made safer with the help of emergency planning, following installing requirements, and of course, labeling any hazards present.
- NFPA 25: Standards for Fire Protection Systems
- Lockout/Tagout Program (How To Control Hazardous Energy)
- Improving Workplace Electrical Safety
- NFPA 70E [Workplace Electrical Safety]
- NFPA 704
- Process Safety Management
- Fire Prevention in the Workplace [OSHA 1910.39]
- Fire Safety in the Workplace
- Arc Flash Label Requirements [2018 Updates]