Grid Interconnection and Compliance Trends

Navigating the world of energy storage regulations

22 November 2016

Energy storage systems (ESS) provide many benefits by integrating different components (equipment for charging, discharging, protection, and fluid movement and containment) and technologies (power conversion, utility grid connection, cooling, communication, and control). With these integrated capabilities, however, come strict and often complex regulatory requirements and assessments.

ESS evaluation involves both the assessment of individual equipment and the system as a whole. Many aspects must be considered, including final connections, installation, application, and the system's intended environment. Any potential safety concerns receive intense scrutiny and are considered on electrical, mechanical, energy, and chemical levels. Many efforts are underway to develop and apply suitable safety standards for the rapidly evolving energy storage and renewable energy industries. Meanwhile, several standards currently exist, which take all of these aspects into consideration.

  • ANSI/UL 9540: Currently the "umbrella" standard for systems that store energy from various sources and provide energy to loads or power conversion equipment. Published in 2014, the standard establishes general requirements for ESS, as well as more specific measures for safety analysis and control systems, safety critical electrical and electronic controls, as well as electrical, mechanical and environmental tests.
  • IEEE 1547-2003 and IEEE 1547.1-2003: Both published in 2003, serve as the current standards for grid connection requirements. IEEE 1547-2003 is concerned with performance, operation, testing, safety considerations and maintenance of the interconnection. IEEE 1547.1-2003 specifies the type, production and commissioning tests needed to demonstrate the interconnection functions and the distributed energy resources comply with IEEE 1547-2003.
  • UL 1741 SA: UL 1741 standard was revised on September 7, 2016, to incorporate the¬†Supplement A (SA). It is intended to validate compliance with grid interactive functions which are not covered in IEEE 1547-2003. The intention of this supplement is to define the evaluation criteria for utility interactive inverters with grid support functions that are rated and specified as "Grid Support Utility Interactive Inverters." This new nomenclature is intended to differentiate these products from "utility interactive inverters."
  • Regional requirements: Specific ¬†regional requirements also must be considered for certain markets:
    • California has established Rule 21 for generating facility interconnections. The Rule is also considered as is a Source Requirement Document (SRD) to be used with the UL 1741 SA. All new utility interactive inverter installations in California are required for the grid support function 12 months after the publication of UL 1741 SA.
    • In Hawaii, the Standard Interconnection Agreement Rule 14H establishes local requirements for grid connection. The inverter requirements of the rule are intended to be consistent with IEEE 1547-2003 and 1547a. As was the case in California, in the event of a conflict between Rule 14H and IEEE 1547-2003, Rule 14H takes precedence.
    • Hawaii also established File TrOV-2, a two-part requirement covering: a test to verify the effects of the DER system on overvoltage on the area EPS and frequency and voltage ride-through (FVRT) testing.
    • Hawaii 14H is also SRD to be used with the UL 1741 SA to build compliance.
  • Battery Standards: Standards specific to batteries exist for a wide variety of battery products including lithium batteries (ANSI/UL 1642), household and commercial batteries (ANSI/UL 2054), uninterruptable power systems (UPS) batteries (ANSI/UL 1989), stationary batteries (UL 1973), and batteries for electric vehicles (ANSI/UL 2580 / 2271).

To bring energy storage solutions to market across rapidly growing and changing industries, it is crucial for manufacturers to understand all global and regional regulatory requirements. Having an in depth knowledge of what is required will improve speed to market and ensure that you are bringing safe, high-quality, and high-performing products to market.

Haiwen (Howard) Liu is an engineering lead at Intertek's Cortland New York facilitiy, where he is responsible for certifying power generation and conversion equipment, researching new standards, technologies, and providing regional and global technical support and guidance. He is a committee member of National Electrical Code (NEC) Code-Making Panel 4, Standard Technical Panel UL 1741, IEEE, and the Eta Kappa Nu Electrical Engineering Honor Society. He received B.S. and M.S. in Electrical Engineering from Zhejiang University, China and a Ph.D. in Electrical Engineering at the University of Tennessee, Knoxville.