UL Standard for Energy Storage Systems and Equipment
|Publication Date:||27 February 2020|
These requirements cover energy storage systems that are intended to receive and store energy in some form so that the energy storage system can provide electrical energy to loads or to the local/area electric power system (EPS) when needed. The types of energy storage covered under this standard include electrochemical, chemical, mechanical and thermal. The energy storage system shall be constructed either as one unitary complete piece of equipment or as matched assemblies, that when connected, form the system. This standard is a system standard, where an energy storage system consists of the an energy storage mechanism, power conversion equipment and balance of plant equipment as shown in Figure 6.1. Individual parts (e.g. power conversion system, battery system, etc.) of an energy storage system are not considered an energy storage system on their own. This standard evaluates the compatibility and safety of these various components integrated into a system.
NOTE: Energy storage systems may include equipment for charging, discharging, control, protection, power conversion, communication, controlling the system environment, air, fire detection and suppression system, fuel or other fluid movement and containment, etc.
The systems covered by this standard include those intended to be used in a standalone mode (e.g. islanded) including "self-supply" systems to provide electrical energy and those used in parallel with an electric power system or electric utility grid such as "grid-supply" systems, or applications that perform ancillary operational modes associated with power generation such as voltage support and regulation, frequency support and regulation, volt-var, capacity reserve, energy shifting or other utility grid support services.
Energy storage systems are intended for installation and use in accordance with the National Electrical Code, NFPA 70, the Canadian Electrical Code, Part I Safety Standard for Electrical Installations, CSA C22.1, the National Electrical Safety Code, IEEE C2, the International Fire Code, ICC IFC, the International Residential Code, ICC IRC, the National Fire Code of Canada, NRC NFC, the Fire Code, NFPA 1, and the Standard for the Installation of Stationary Energy Storage Systems, NFPA 855. Requirements for installation, with the exception of installation manuals and documents for installation provided with the system are outside the scope of this standard.
This standard covers energy storage systems for stationary indoor and outdoor installations. This standard also covers mobile energy storage systems as defined by this standard. The standard includes requirements for energy storage systems used in residential installations, non-residential installations and wall-mounted applications.
Systems using lead acid or Ni-cad batteries that fall within the scope of UL 1778 and only serve an uninterruptible power system (UPS) application are outside the scope of this standard.
The maximum energy capacity of individual electrochemical ESS shall not exceed the following values:
a) Outdoor wall mounted electrochemical ESS shall not exceed 20 kWh (72 MJ);
b) Residential use electrochemical ESS shall not exceed 20 kWh (72 MJ); and
c) Non-residential use electrochemical ESS shall not exceed 50 kWh (180 MJ), except as allowed in 1.7 - 1.11.
With reference to 1.6, there is no maximum energy capacity limit for non-residential use electrochemical ESS that are tested in accordance with the Standard for Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems, UL 9540A in which the performance level criteria of the cell level test have been met.
With reference to 1.6, the maximum energy capacity of non-residential use electrochemical ESSs shall be permitted to be increased to the value of the unit which complies with the UL 9540A Unit Level Test.
With reference to 1.6, the maximum energy capacity of non-residential use electrochemical ESSs shall be permitted to be increased to the value of the unit which complies with the UL 9540A Performance criteria for the Installation Level test, and the ESS shall be marked in accordance with 41.13.
With reference to 1.6, there is no maximum energy capacity limit for non-residential use electrochemical ESS intended for use in remote outdoor locations as defined in the applicable installation code, provided they are marked in accordance with 41.15. The Standard for the Installation of Stationary Energy Storage Systems, NFPA 855 defines outdoor remote locations as being located more than 30.5 m (100 ft) from exposures.
With reference to 1.6, lead acid and Ni-Cad energy storage systems have exceptions to the capacity energy limits including, in some cases, no limits based upon specific telecom and utility installations as outlined in NFPA 855.