The Federal Energy Regulatory Commission (FERC) recently issued two orders designed to address electric grid reliability implications raised by the dramatic growth in solar and wind projects. Renewable project owners and operators should follow these developments closely, as FERC’s orders propose to substantially increase registration and compliance requirements.  

Background 

Historically, virtually all power plants consisted of synchronous generation resources capable of riding through system disturbances. In contrast, inverter-based resources (IBRs), such as most solar and wind projects, are not directly synchronized to the electric grid, and they must be programmed to “ride through” disturbances to avoid tripping offline. As the current regime of “Reliability Standards” implemented by the North American Electric Reliability Corporation (NERC) (and subject to FERC approval) were designed primarily with synchronous generation in mind, FERC is concerned that the existing Reliability Standards inadequately address the aggregate reliability impact risks created by IBRs. According to NERC, these risks have caused or contributed to several outages in recent years.  

To address these concerns, on Nov. 17, FERC took the actions summarized below.  

NERC Registration of Inverter-Based Resources 

In its Registration of Inverter-Based Resources order, FERC seeks to address the aggregate reliability impact of the subset of renewable projects exempt from NERC’s Reliability Standards. Many such IBRs are exempt because they do not meet the “bright line” test of having to register with NERC (i.e., if the generating facility’s aggregate capacity exceeds 75 MVA sharing a point of interconnection to the transmission system at a voltage at or above 100 kV). NERC has found in several instances that the aggregate impact of such IBRs tripping offline can exacerbate a system reliability event.  

To address this gap, FERC directs NERC to submit a “work plan” to identify and register unregistered IBRs that, “in the aggregate, have a material impact on the reliable operation of the Bulk-Power System.”  NERC must submit its work plan by February 15, 2023. The order provides that all such IBR owners and operators will be identified and registered within three years of FERC approving NERC’s work plan.  

Although FERC is not soliciting comments on this order, FERC will entertain comments on NERC’s work plan, once submitted.  

Proposal to Require Reliability Standards to Address Inverter-Based Resources

In its Reliability Standards to Address Inverter-Based Resources proposal, FERC directs NERC to submit new or modified Reliability Standards to address four issues:   

• Require generator owners, transmission owners, and distribution providers to share validated modeling, planning, operations, and disturbance monitoring data for IBRs with system operators and planners (Data Sharing);  
• Ensure that IBR models are comprehensive, validated, and timely, so that they can adequately predict the behavior of all IBRs and their impacts on reliability (Model Validation);
• Ensure that validated IBR models are included in planning and operational studies to assess IBRs’ reliability impacts, both individually and in the aggregate, as well as IBR-DERs in the aggregate (Planning and Operational Studies); and 
• Ensure that registered IBRs provide frequency and voltage support during frequency and voltage excursions adequate to contribute toward the overall system needs (Performance Requirements).  

Comments on FERC’s proposal to require NERC to create new Reliability Standards are due 60 days after publication in the Federal Register, and reply comments are due 30 days thereafter. FERC also proposes that, once FERC issues a final rule, NERC must submit the new or modified Reliability Standards within 90 days of the final rule’s effective date.