IEC 62933-2-1 specifies the unit parameters and testing methods for electrical energy storage (EES) systems, published by the International Electrotechnical Commission (IEC). It defines the standardised test procedures used to characterise the performance of a complete EES system unit — including capacity, power, efficiency, and response time — providing manufacturers, customers, and regulators with a common basis for comparing and verifying EES system performance claims.
Published by: International Electrotechnical Commission (IEC)
Current edition: IEC 62933-2-1:2017
Companion standards: IEC 62933-1 (terminology), IEC 62933-2-2 (application and performance testing), IEC 62933-5-1 (grid safety)
Scope
IEC 62933-2-1 applies to grid-connected EES system units, covering battery-based systems (lithium-ion, lead-acid, flow batteries), flywheel systems, and other electrochemical and electromechanical storage technologies. The standard defines the parameters that characterise EES system performance and the test procedures to measure them, at the system boundary (the AC or DC connection point between the EES system and the grid or load).
Key Parameters and Tests
The standard defines and specifies measurement methods for rated energy capacity (the total energy the system can store and deliver under defined conditions), rated power (maximum continuous charge and discharge power), round-trip efficiency (the ratio of energy delivered on discharge to energy consumed on charge, across a complete cycle), response time (the time from receiving a power command to reaching the commanded power output — critical for frequency regulation applications), and ramp rate (the rate at which output power can change). Tests are conducted at defined temperatures, initial states of charge, and power levels to ensure reproducibility.
Relevance to Battery Engineering
IEC 62933-2-1 is the reference standard for performance characterisation of BESS systems for grid applications. Battery engineers and system integrators use its test procedures to validate system-level performance against procurement specifications and to generate the performance data required for grid operator certification and capacity market participation. The standard’s definition of round-trip efficiency is particularly important — efficiency claims based on different test protocols can vary significantly, and IEC 62933-2-1 provides the standardised basis for valid comparison between competing systems.
Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.