5 of NFPA 855, we learn that individual ESS units shall be separated from each other by a minimum of three feet unless smaller separation distances are documented to be adequate and approved by the authority having jurisdiction (AHJ) based on large-scale fire testing.
Can energy storage systems be installed in certain areas?
Energy storage systems can pose a potential fire risk and therefore shouldn't be installed in certain areas of the home. NFPA 855 only permits residential ESS to be installed in the following areas:
What is an energy storage system?
An energy storage system is something that can store energy so that it can be used later as electrical energy. The most popular type of ESS is a battery system and the most common battery system is lithium-ion battery.
How much energy can a ESS unit store?
Individual ESS units shall have a maximum stored energy of 20 kWh per NFPA Section 15.7. NFPA 855 clearly tells us each unit can be up to 20 kWh, but how much overall storage can you put in your installation? That depends on where you put it and is defined in Section 15.7.1 of NFPA 855.
Why do we need energy storage systems?
Growing concerns about the use of fossil fuels and greater demand for a cleaner, more eficient, and more resilient energy grid has led to the use of energy storage systems (ESS), and that use has increased substantially over the past decade.
How many ESS units can be installed on a wall?
The diagram shows that each ESS unit can have a maximum rating of 20 kWh, and if you're going to install two units, let's say outside on your wall, you need to have the appropriate spacing between those units and three-feet separation from doors and windows per NFPA 855 15.6.1.