There needs to be greater scrutiny on battery energy storage devices to ensure reliable performance of the bulk electric system, according to a joint report from the North American Electric Reliability Corporation and the Western Electricity Coordinating Council.
The 2022 California Battery Energy Storage System Disturbances report assesses two events involving the unexpected, abnormal performance of bulk power system-connected battery energy storage systems initiated by normally cleared faults in the Western Interconnection that occurred on March 9 and April 6 in 2022.
NERC called the events, “the first significant events involving battery energy storage system facilities, highlighting the need to consider these systems in the same light as any other inverter-based resource.”
“These events are the first faint signal that the systemic performance issues we have identified with other inverter-based technologies may very likely apply here as well,” Ryan Quint, NERC’s director of engineering and security integration, said in a statement. “Battery energy storage systems will play a critical role during the energy transition; therefore, it is imperative that we design, study, commission, and operate them in a manner that supports BPS reliability.”
The report found that battery energy storage systems may have the same systemic performance problems as solar photovoltaic resources. It also found that battery energy storage system ride-through performance is not adequately assessed during the interconnection process and that poor commissioning practices are a “significant contributor” to the unreliable performance of inverter-based resources. NERC said it plans to conduct a model quality assessment of the event and issue an alert, as needed.
The report also said that generation owners should check with their inverter manufacturer to ensure that their inverters are not prone to tripping on the following causes, in addition to those previously reported, during normally cleared unbalanced grid faults:
- unexpected, unbalanced alternating current,
- unexpected direct current bus overvoltage tripping, and
- unstable DC bus voltage.
The report also recommended that generation owners should ensure both inverter- and plant-level recording functions are configured to meet the requirements in the interconnection agreements and that generation owners should ensure fast logging is enabled and that meter data does not freeze on the last value when subjected to system transients during grid faults.
NERC said that through its Inverter-Based Resource Strategy, it is identifying and addressing risks and risk mitigation techniques with industry and providing best practices and education and that through the ERO Enterprise, made up of NERC and the six regional entities, it will continue to analyze disturbances that involve widespread reductions of inverter-based resources to identify any reliability issues, support affected facilities in developing mitigating measures and share key findings and recommendations with industry for increased awareness and action.
