Groups Urge FERC to Take Account of Industry, NERC Efforts Tied to Inverter-Based Resources

The Federal Energy Regulatory Commission should work to ensure that any directives FERC ultimately issues in an ongoing proceeding related to inverter-based resources and reliability capitalizes and dovetails with related work already underway by the North American Electric Reliability Corporation and the power sector, the American Public Power Association and other groups recently said.

IBRs are solar photovoltaic, wind, fuel cell and battery storage resources that use power electronic devices to change direct current power, produced by generators, to alternating current power, to be transmitted on the bulk-power system. “As use of this technology grows, it is important to ensure that IBRs do not adversely impact the technical reliability of the grid,” FERC noted last year.

The comments submitted by the groups to FERC on Feb. 6 were filed in response to a Notice of Proposed Rulemaking issued by the Commission in late 2022. In November 2022, FERC Commissioners  approved an order and a NOPR containing directives and proposed directives to the North American Electric Reliability Corporation, to account for the increasing number of IBRs in the nation’s resource mix. 

Joining APPA in the comments were the Large Public Power Council, the National Rural Electric Cooperative Association, the Transmission Access Policy Study Group and Edison Electric Institute.

The NOPR proposes to direct NERC to develop new or modified reliability standards that address the following issues related to inverter-based resources: data sharing; model validation; planning and operational studies; and performance requirements.

The trade associations said in their comments that they agree with the Commission that new or revised standards are needed to manage the impact of the rapidly increasing presence of IBRs on the Bulk Electric System. The groups “recognize, as does the Commission, that the topics addressed in this NOPR are broad and impact issues within multiple jurisdictions, including those overseen by state and local retail regulators, and coordination among them is critical.”

They said that undoubtedly, there is a category of IBRs that should be subject to certain standards.  Critical to ensuring that the reliability standards properly apply to IBRs is identifying and registering the IBRs that have a material impact on the bulk power system, APPA and the other groups said.

At the same time, the groups pointed out that NERC has launched a series of related initiatives aimed at the collection and sharing of IBR data, model validation, IBR planning and operational studies and needed IBR performance requirements. 

“While this certainly does not mean the Commission’s proposed directives are mislaid, it seems critical for NERC and the industry to be able to work cooperatively to shape these standards in ways that enhance the industry’s ability to plan and operate the grid reliably,” they said.

The groups recognize the NOPR’s proposal is to direct NERC to make a compliance filing within 90 days of any final rule explaining how it is prioritizing its IBR reliability standard projects to meet the directive in the final rule.

“We support that proposed directive, but also ask that NERC provide a plan ensuring that the significant work undertaken to date is not in vain; that the ensuing work of the drafting teams is fully informed by this work; and that the recommended standards be shaped by the work undertaken to date,” APPA and the other groups said.

The groups included details on various NERC projects relevant to the NOPR.

The groups also said that FERC should not require distribution providers and transmission owners to collect and share data and model information supporting IBR-distributed energy resources (IBR-DERs) that they cannot reasonably obtain.

With respect to sharing of IBR data, the Commission proposes that transmission owners should provide planning coordinators and other entities with detailed modeling data and parameters for unregistered IBRs with an aggregate material effect on operation of the BPS. The Commission would also require such information sharing by distribution providers for IBR-DERs.

Similarly, the Commission proposes to (1) require transmission owners to provide validated unregistered IBR models to the planning coordinators for interconnection-wide planning and operational models; and (2) require distribution providers to provide validated models of IBR-DERs in the aggregate to the planning coordinators for interconnection-wide planning and operational models. 

The NOPR recognizes that it may not be practical for distribution providers to provide modeling data and parameters to model individual IBR-DERs directly, in light of the small size and location of many of the IBR-DERs on the distribution system.

The NOPR thus proposes that distribution providers be permitted to provide IBR-DER modeling data and parameters in the aggregate or equivalent.

The groups said they appreciate that the Commission recognizes the practical challenges of modeling individual IBR-DERs. 

“But a more fundamental challenge must also be acknowledged: A registered entity cannot provide data that the registered entity itself does not have and has no ability to collect,” they said.

“In particular, it would be unrealistic to expect a transmission owner or distribution provider to have information about unregistered IBRs and IBR-DERs at the same level of detail and accuracy that registered generator owners can provide about their own facilities.”

In most if not all cases, the transmission owner or distribution provider has only the information provided to it during the interconnection approval process, APPA and the other groups said.

“Interconnection agreements may not require the IBRs to provide modeling data, and transmission owners and distribution providers may not have the contractual right to add such requirements unilaterally and retroactively. Furthermore, some IBR-DERs on the distribution system interconnect under utility retail tariffs without a separate interconnection agreement.”

The practical limitations that transmission owners and distribution providers have to collect and model data regarding unregistered IBRs and IBR-DERs are unlikely to have a significant adverse impact on BPS reliability due to a number of factors, the groups said.

In the alternative, the Commission should limit the obligations to be shouldered by distribution providers and transmission owners to what is feasible, the groups said.

“In ascertaining what it is realistic to require of transmission owners and distribution providers with respect to asset owners they do not control, the Commission may consider convening a forum to consider the relative benefits of directing new or revised reliability standards applying to distribution providers with IBR-DERs, or else directing NERC to submit a study on the challenges of developing and implementing such standards.”