Reliability Standards To Address Inverter-Based Resources

Federal RegisterOct 30, 2023

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DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

18 CFR Part 40

[Docket No. RM22-12-000; Order No. 901]

Reliability Standards To Address Inverter-Based Resources

AGENCY:

Federal Energy Regulatory Commission, Department of Energy.

ACTION:

Final action.

SUMMARY:

The Federal Energy Regulatory Commission (Commission) is directing the North American Electric Reliability Corporation (NERC), the Commission-certified Electric Reliability Organization, to develop new or modified Reliability Standards that address reliability gaps related to inverter-based resources in the following areas: data sharing; model validation; planning and operational studies; and performance requirements. The Commission is also directing NERC to submit to the Commission an informational filing within 90 days of the issuance of this final action that includes a detailed, comprehensive standards development plan providing that all new or modified Reliability Standards necessary to address the inverter-based resource-related reliability gaps identified in this final action be submitted to the Commission by November 4, 2026.

DATES:

This rule is effective December 29, 2023.

FOR FURTHER INFORMATION CONTACT:

Eugene Blick (Technical Information), Office of Electric Reliability, Federal Energy Regulatory Commission, 888 First Street NE, Washington, DC 20426, (202) 502-8803,

Eugene.Blick@ferc.gov

Felicia West (Legal Information), Office of the General Counsel, Federal Energy Regulatory Commission, 888 First Street NE, Washington, DC 20426, (202) 502-8948,

Felicia.West@ferc.gov

SUPPLEMENTARY INFORMATION:

Table of Contents

Paragraph Nos.

I. Information

II. Background

A. Section 215 of the FPA and the Mandatory Reliability Standards

B. Inverter-Based Resources

C. Notice of Proposed Rulemaking

III. Need for Reform

A. Current Actions Are Insufficient To Address IBR Reliability Risks

B. Existing Reliability Standards Do Not Adequately Address IBR Reliability Risks

1. Data Sharing

2. Data and Model Validation

3. Planning and Operational Studies

4. Performance Requirements

IV. Discussion

A. Commission Authority To Direct the ERO To Develop New or Modified Reliability Standards Under Section 215 of the FPA

1. Comments

2. Commission Determination

B. Data Sharing

1. Registered IBR Data Sharing

2. Disturbance Monitoring Data Sharing

3. Unregistered IBR and IBR-DER Data Sharing

C. Data and Model Validation

110

1. Approved Component Models

112

2. Verification of IBR Plant Dynamic Model Performance

128

3. Validating and Updating System Models

151

4. Need for Coordination When Creating and Updating Planning, Operational, and Interconnection-Wide Data and Models

158

D. Planning and Operational Studies

162

1. Comments

167

2. Commission Determination

174

E. Performance Requirements

178

1. Registered IBR Frequency and Voltage Ride Through Requirements

178

2. Bulk-Power System Planners and Operators Voltage Ride Through Mitigation Activities

196

3. Post-Disturbance IBR Ramp Rate Interactions and Phase Lock Loop Synchronization

200

F. Informational Filing and Reliability Standard Development Timeline

212

1. Comments

214

2. Commission Determination

222

V. Information Collection Statement

231

VI. Environmental Analysis

234

VII. Regulatory Flexibility Act

235

VIII. Document Availability

237

IX. Effective Date and Congressional Notification

240

Appendix A: Commenter Names

Appendix B: NERC IBR Resources Cited in the Final Action

I. Introduction

1. Pursuant to section 215(d)(5) of the Federal Power Act (FPA),

the Federal Energy Regulatory Commission (Commission) directs the North American Electric Reliability Corporation (NERC), the Commission-certified Electric Reliability Organization (ERO), to submit new or modified Reliability Standards

that address specific matters pertaining to the impacts of inverter-based resources (IBR)

on the reliable operation

of the Bulk-Power System.

As proposed in the notice of proposed rulemaking (NOPR), we direct NERC to develop new or modified Reliability Standards addressing reliability gaps pertaining to IBRs in four areas: (1) data sharing; (2) model validation; (3) planning and operational studies; and (4) performance requirements.

NERC may propose to develop new or modified Reliability Standards that address our concerns in an equally efficient and effective manner; however, NERC's proposal should explain how the new or modified Reliability Standards address the Commission's concerns discussed in this final action.

16 U.S.C. 824o(d)(5) (the Commission may order the Electric Reliability Organization (ERO) to submit to the Commission a proposed Reliability Standard or a modification to a Reliability Standard that addresses a specific matter if the Commission considers such a new or modified Reliability Standard appropriate to carry out FPA section 215).

The FPA defines Reliability Standard as requirements for the operation of existing Bulk-Power System facilities, including cybersecurity protection, and the design of planned additions or modifications to such facilities to the extent necessary to provide for reliable operation of the Bulk-Power System, but the term does not include any requirement to enlarge such facilities or to construct new transmission capacity or generation capacity.

Id.

824o(a)(3);

see also

18 CFR 39.1.

This final action uses the term IBR generally to include all generation resources that connect to the electric power system using power electronic devices that change direct current (DC) power produced by a resource to alternating current (AC) power compatible with distribution and transmission grids. IBRs may refer to solar photovoltaic (PV), wind, fuel cell, and battery storage resources.

The FPA defines reliable operation as operating the elements of the Bulk-Power System within equipment and electric system thermal, voltage, and stability limits so that instability, uncontrolled separation, or cascading failures of such system will not occur as a result of a sudden disturbance, including a cybersecurity incident, or unanticipated failure of system elements. 16 U.S.C. 824o(a)(4);

see also

18 CFR 39.1.

The Bulk-Power System is defined in the FPA as facilities and control systems necessary for operating an interconnected electric energy transmission network (or any portion thereof), and electric energy from generating facilities needed to maintain transmission system reliability. The term does not include facilities used in the local distribution of electric energy. 16 U.S.C. 824o(a)(1);

see also

18 CFR 39.1.

Reliability Standards to Address Inverter-based Res.,

Notice of Proposed Rulemaking, 87 FR 74541 (Dec. 6, 2022), 181 FERC ¶ 61,125, at P 1 (2022) (NOPR).

See, e.g., Mandatory Reliability Standards for the Bulk-Power Sys.,

Order No. 693, 72 FR 16416 (Apr. 4, 2007), 118 FERC ¶ 61,218, at PP 186, 297,

order on reh'g,

Order No. 693-A, 72 FR 40717 (July 25, 2007), 120 FERC ¶ 61,053 (2007) (“[W]here the Final Rule identifies a concern and offers a specific approach to address the concern, we will consider an equivalent alternative approach provided that the ERO demonstrates that the alternative will address the Commission's underlying concern or goal as efficiently and effectively as the Commission's proposal.”).

2. We take this action in light of the rapid change in the mix of generation resources

connecting to the Bulk-Power System, including the addition of an “unprecedented proportion of nonsynchronous resources”

projected to connect over the next decade, including many generation resources that employ inverters, rectifiers, and converters

to provide energy to the Bulk-Power System. According to NERC, the rapid integration of IBRs is “the most significant driver of grid transformation” on the Bulk-Power System.

The Reliability Standards use both terms “generation resources” and “generation facilities” to define sources of electric power on the transmission system. This final action uses the term “generation resources.”

NERC,

2020 Long Term Reliability Assessment Report,

9 (Dec. 2020),

https://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/NERC_LTRA_2020.pdf

(2020 LTRA Report).

An inverter is a power electronic device that inverts DC power to AC sinusoidal power. A rectifier is a power electronic device that rectifies AC sinusoidal power to DC power. A converter is a power electronic device that performs rectification and/or inversion. Consistent with NERC's terminology, this order uses the term “inverter” to refer to generating facilities that use power electronic inversion, rectification, and conversion. NERC,

Inverter-Based Resource Performance and Analysis Technical Workshop,

29 (Feb. 2019),

https://www.nerc.com/comm/PC/IRPTF%20Workshops/IRPTF_Workshop_Presentations.pdf

NERC,

Inverter-Based Resource Strategy: Ensuring Reliability of the Bulk Power System with Increased Levels of BPS-Connected IBRs,

1 (June 2022),

https://www.nerc.com/comm/Documents/NERC_IBR_Strategy.pdf

(NERC IBR Strategy).

3. The Reliability Standards, first approved by the Commission in 2007, were developed to apply to the types of generation resources prevalent at that time—nearly exclusively synchronous generation resources—to ensure the reliable operation of the Bulk-Power System. As a result, the Reliability Standards may not account for the material technological differences between the response of synchronous generation resources and the response of IBRs to the same disturbances on the Bulk-Power System.

See, e.g.,

NERC,

2013 Long-Term Reliability Assessment,

22 (Dec. 2013),

https://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/2013_LTRA_FINAL.pdf

(2013 LTRA Report) (finding that reliably integrating high levels of variable resources into the Bulk-Power System would require “significant changes to traditional methods used for system planning and operation,” including requiring “new tools and practices, including potential enhancements to . . . Reliability Standards or guidelines to maintain [Bulk-Power System] reliability.”).

4. We also take this action because, as discussed in more detail in section III below, we find that the currently effective Reliability Standards do not ensure that Bulk-Power System planners and operators

have the necessary tools to plan for and reliably integrate IBRs into the Bulk-Power System or to plan for IBRs connected to the distribution system that in the aggregate have a material impact on the Bulk-Power System (IBR-DER). IBRs, individually and in the aggregate, and IBR-DERs in the aggregate can have a material impact on the reliable operation of the Bulk-Power System.

Additionally, the Reliability Standards do not contain performance requirements that are unique to IBRs and are necessary to ensure that IBRs operate in a predictable and reliable manner.

Bulk-Power System planners and operators include planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities, and any other functional entity NERC may identify as applicable to meet the directives in this final action.

NERC reports do not always differentiate between IBRs based on type, or between those subject to Reliability Standards and those located on the distribution system. Where necessary to describe our directives, however, we differentiate between IBRs registered with NERC (or which will be registered pursuant to the Commission's directives in

Registration of Inverter-based Resources,

181 FERC ¶ 61,124 (2022) (IBR Registration Order)) and therefore subject to the Reliability Standards (

i.e.,

registered IBR), IBRs connected directly to the Bulk-Power System but not registered with NERC and therefore not subject to the Reliability Standards (

i.e.,

unregistered IBRs), and IBRs connected to the distribution system that in the aggregate have a material impact on the Bulk-Power System (

i.e.,

IBR-DER). Although the remaining subset of unregistered IBRs and IBR-DERs in the aggregate will not be subject to the mandatory and enforceable Reliability Standards set forth herein, they may be subject to provision of data and information to their respective transmission owners and distribution providers, as applicable, in accordance with their specific interconnection agreements. We encourage NERC to continue its efforts to review and evaluate whether reliability gaps continue to remain and if new or modified functional registration categories or Reliability Standards are necessary.

See infra

note 365 (discussing NERC's estimate of the percentage of IBRs to be registered under its registration work plan).

5. As discussed in greater detail below, we therefore direct NERC, pursuant to section 215(d)(5) of the FPA and § 39.5(f) of the Commission's regulations, to develop new or modified Reliability Standards that address the following specific issues:

•

IBR Data Sharing:

The Reliability Standards must require that generator owners, transmission owners, and

distribution providers share validated modeling, planning, operations, and disturbance monitoring data for all IBRs with planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities so that the latter group has the necessary data to predict the behavior of registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate, and their impact on the reliable operation of the Bulk-Power System.

•

IBR Model Validation:

The Reliability Standards must require that all IBR models are comprehensive, validated, and updated in a timely manner, so that planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities can adequately predict the behavior of registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate, and their impacts on the reliable operation of the Bulk-Power System.

•

IBR Planning and Operational Studies:

The Reliability Standards must require that planning and operational studies include validated IBR models to assess the reliability impacts of registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate, on the reliable operation of the Bulk-Power System. The Reliability Standards must require that planning and operational studies assess the impacts of all IBRs within and across planning and operational boundaries for normal operations and contingency event conditions.

•

IBR Performance Requirements:

The Reliability Standards must ensure that registered IBRs will provide frequency and voltage support during frequency and voltage excursions in a manner necessary to contribute toward the overall system needs for essential reliability services.

The Reliability Standards must establish clear and reliable technical limits and capabilities for registered IBRs to ensure that all registered IBRs are operated in a predictable and reliable manner during normal operations and contingency event conditions. The Reliability Standards must require that the operational aspects of registered IBRs contribute towards meeting the overall system needs for essential reliability services. The Reliability Standards must include post-disturbance ramp rates and phase lock loop synchronization requirements for registered IBRs.

See, e.g.,

NERC,

A Concept Paper on Essential Reliability Services that Characterizes Bulk Power System Reliability,

vi (Oct. 2014),

https://www.nerc.com/comm/Other/essntlrlbltysrvcstskfrcDL/ERSTF%20Concept%20Paper.pdf

(Essential Reliability Services Concept Paper) (listing the essential reliability services necessary to maintain Bulk-Power System reliability).

6. Pursuant to § 39.2(d) of the Commission's regulations,

we direct NERC to submit an informational filing within 90 days of the issuance of the final action in this proceeding. NERC's filing shall include a detailed and comprehensive standards development plan explaining how NERC will prioritize the development of new or modified Reliability Standards to meet the deadlines set forth in this final action. We direct NERC to explain in its filing how it is prioritizing its IBR Reliability Standard projects to meet the directives in this final action, taking into account the risk posed to the reliability of the Bulk-Power System, standard development projects already underway, resource constraints, and other factors if necessary.

18 CFR 39.2(d) (the electric reliability organization shall provide the Commission information as necessary to implement section 215 of the FPA).

7. NERC's standards development plan must ensure that NERC submits new or modified Reliability Standards by the following deadlines. First, by November 4, 2024, NERC must submit new or modified Reliability Standards that establish IBR performance requirements, including requirements addressing frequency and voltage ride through,

post-disturbance ramp rates, phase lock loop synchronization, and other known causes of IBR tripping or momentary cessation.

NERC must also submit, by November 4, 2024, new or modified Reliability Standards that require disturbance monitoring data sharing and post-event performance validation for registered IBRs. Second, by November 4, 2025, NERC must submit new or modified Reliability Standards addressing the interrelated directives concerning: (1) data sharing for registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate; and (2) data and model validation for registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate. Finally, by November 4, 2026, NERC must submit new or modified Reliability Standards addressing planning and operational studies for registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate. We continue to believe this staggered approach to standard development and implementation is necessary based on the scope of work anticipated and that specific target dates will provide a valuable tool and incentive to NERC to timely address the directives in this final action.

See Standardization of Generator Interconnection Agreements & Procs.,

Order No. 2003, 104 FERC ¶ 61,103, at P 562 n.88 (2003) (defining ride through as “a Generating Facility staying connected to and synchronized with the Transmission System during system disturbances within a range of over- and under-frequency[/voltage] conditions, in accordance with Good Utility Practice.”).

Momentary cessation is a mode of operation during which the inverter remains electrically connected to the Bulk-Power System, but the inverter does not inject current during low or high voltage conditions outside the continuous operating range. As a result, there is no current injection from the inverter and therefore no active or reactive current (and no active or reactive power). NERC,

Reliability Guideline: BPS-Connected Inverter-Based Resource Performance,

11 (Sept. 2018),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Inverter-Based_Resource_Performance_Guideline.pdf

(IBR Performance Guideline).

8. Although we are not directing NERC to include implementation dates in its informational filing and are leaving determination of the appropriate effective dates to the standards development process, we are concerned that the lack of a time limit for implementation could allow identified issues to remain unresolved for a significant and indefinite period. Therefore, we emphasize that industry has been aware of and alerted to the need to address the impacts of IBRs on the Bulk-Power System since at least 2016. The number of events, NERC Alerts, reports, whitepapers, guidelines, and ongoing standards projects, as discussed in more detail in section III and throughout this final action, more than demonstrate the need for the expeditious implementation of new or modified Reliability Standards addressing IBR data sharing, data and model validation, planning and operational studies, and performance requirements. Thus, in that light, the Commission will take these issues into account when it considers the proposed implementation plan for each new or modified Reliability Standard when it is submitted for Commission. Further, as a general matter, we believe that there is a need to have all the directed Reliability Standards effective and enforceable well in advance of 2030 and direct NERC to ensure that the associated implementation plans sequentially stagger the effective and enforceable dates to ensure an orderly industry transition for complying with the IBR directives in this final action prior to 2030.

II. Background

A. Section 215 of the FPA and the Mandatory Reliability Standards

9. Section 215 of the FPA provides that the Commission may certify an

ERO, the purpose of which is to develop mandatory and enforceable Reliability Standards, subject to Commission review and approval.

Reliability Standards may be enforced by the ERO, subject to Commission oversight, or by the Commission independently.

Pursuant to section 215 of the FPA, the Commission established a process to select and certify an ERO,

and subsequently certified NERC.

16 U.S.C. 824o(c).

Id.

824o(e).

Rules Concerning Certification of the Elec. Reliability Org. & Procs. for the Establishment, Approval, & Enf't. of Elec. Reliability Standards,

Order No. 672, 114 FERC ¶ 61,104,

order on reh'g,

Order No. 672-A, 114 FERC ¶ 61,328 (2006).

N. Am. Elec. Reliability Corp.,

116 FERC ¶ 61,062,

order on reh'g and compliance,

117 FERC ¶ 61,126 (2006),

aff'd sub nom. Alcoa, Inc.

FERC,

564 F.3d 1342 (D.C. Cir. 2009).

10. Pursuant to section 215(d)(5) of the FPA, the Commission has the authority, upon its own motion or upon complaint, to order the ERO to submit to the Commission a proposed Reliability Standard or a modification to a Reliability Standard that addresses a specific matter if the Commission considers such a new or modified Reliability Standard appropriate to carry out section 215 of the FPA.

Further, pursuant to § 39.5(g) of the Commission's regulations, the Commission may order a deadline by which the ERO must submit a proposed or modified Reliability Standard.

16 U.S.C. 824o(d)(5).

18 CFR 39.5(g).

B. Inverter-Based Resources

11. The Bulk-Power System generation fleet has traditionally been composed almost exclusively of synchronous generation resources that convert mechanical energy into electric energy through electromagnetic induction. By virtue of the kinetic energy in their large rotating components, these synchronous generation resources inherently resist changes in system frequency, providing time for other governor controls (when properly configured) to maintain supply and load balance. Similarly, synchronous generation resources inherently provide voltage support during voltage disturbances.

12. In contrast, IBRs do not use electromagnetic induction from machinery that is directly synchronized to the Bulk-Power System. Instead, the majority of installed IBRs use grid-following inverters, which rely on sensed information from the grid (

e.g.,

a voltage waveform) to produce the desired AC real and reactive power output.

Due to their inverters, IBRs can track grid state parameters (

e.g.,

voltage angle) in milliseconds and react nearly instantaneously to changing grid conditions. Some IBRs, however, are not configured or programmed to support grid voltage and frequency in the event of a system disturbance, and, as a result, will reduce power output,

exhibit momentary cessation, or trip in response to variations in system voltage or frequency.

In other words, under certain conditions some IBRs cease to provide power to the Bulk-Power System due to how they are configured and programmed. Nonetheless, some models and simulations incorrectly predict that some IBRs will ride through disturbances,

i.e.,

maintain real power output at pre-disturbance levels and provide voltage and frequency support consistent with Reliability Standard PRC-024-3 (Frequency and Voltage Protection Settings for Generating Resources).

See, e.g.,

NERC,

2021 Long Term Reliability Assessment Report,

6 (Dec. 2021),

https://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/NERC_LTRA_2021.pdf

(2021 LTRA Report) (“IBRs respond to disturbances and dynamic conditions based on programmed logic and inverter controls, not mechanical characteristics.”);

see also

NERC,

Fast Frequency Response Concepts and Bulk Power System Reliability Needs,

5 (Mar. 2020),

https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Fast_Frequency_Response_Concepts_and_BPS_Reliability_Needs_White_Paper.pdf

(Fast Frequency Response White Paper) (explaining that as the instantaneous penetration of IBRs with little or no inertia continues to increase, system rate of change of frequency after a loss of generation will increase and the time available to deliver frequency responsive reserves will shorten, and illustrating the steeper rate of change of frequency and the importance of speed of response).

The NOPR referred to Reliability Standard PRC-024-2; however, Reliability Standard PRC-024-3 became mandatory and enforceable on October 1, 2022. Reliability Standards applicable in the United States, both effective and retired, are available at

https://www.nerc.com/pa/Stand/Pages/USRelStand.aspx

13. IBRs across the Bulk-Power System exhibit common mode failures that are amplified when IBRs act in the aggregate.

Thus, both localized and interconnection-wide IBR issues must be identified, studied, and mitigated to preserve Bulk-Power System reliability.

Although IBRs are typically smaller-megawatt (MW) facilities, they are at greater risk than synchronous generation resources of ceasing to provide power to the Bulk-Power System in response to a single fault on the transmission or sub-transmission systems. Specifically, such response can occur when individual IBR controls and equipment protection settings are not configured to ride through system disturbances.

IBRs that enter momentary cessation may act in aggregate and cause a reduction in power output far in excess of any individual IBR's impact on the Bulk-Power System. The potential impact of IBRs is not restricted by the size of a single facility or an individual balancing authority area, but by the number of IBRs or percent of generation made up by IBRs within a region. In areas of high IBR penetration, this type of aggregate response may have an impact much greater than the most severe single contingency (

i.e.,

the traditional worst-case N-1 contingency)

of a balancing authority area, potentially adversely affecting other balancing authority areas within an interconnection.

Unless

IBRs are configured and programmed to ride through normally cleared transmission faults, the potential impact of losing IBRs individually or in the aggregate will continue to increase as IBRs are added to the Bulk-Power System and make up an increasing proportion of the resource mix.

NERC,

An Introduction to Inverter-Based Resources on the Bulk-Power System,

6 (June 2023),

https://www.nerc.com/pa/Documents/2023_NERC_Guide_Inverter-Based-Resources.pdf

(explaining that “NERC continues to analyze large-scale grid disturbances involving common mode failures in inverter-based resources that, if not addressed, could lead to catastrophic events in the future”).

See

NOPR, 181 FERC ¶ 61,125 at P 4.

See, e.g.,

NERC and WECC,

900 MW Fault Induced Solar Photovoltaic Resource Interruption Disturbance Report,

19 (Feb. 2018),

https://www.nerc.com/pa/rrm/ea/October%209%202017%20Canyon%202%20Fire%20Disturbance%20Report/900%20MW%20Solar%20Photovoltaic%20Resource%20Interruption%20Disturbance%20Report.pdf

(Canyon 2 Fire Event Report) (covering the Canyon 2 Fire event (October 9, 2017)) (finding momentary cessation as a major cause for the loss of IBRs when voltages rose above 1.1 per unit or decreased below 0.9 per unit).

The most severe single contingency, or the N-1 contingency, generally refers to the concept that a system must be able to withstand an unexpected failure or outage of a single system component and maintain reliable service at all times.

See, e.g.,

NERC,

Glossary of Terms Used in NERC Reliability Standards,

17 (Mar. 8, 2023),

https://www.nerc.com/pa/Stand/Glossary%20of%20Terms/Glossary_of_Terms.pdf

(NERC Glossary) (defining “most severe single contingency”).

See, e.g.,

San Fernando Disturbance Report at vi (stating that “[t]his event, as with past events, involved a significant number of solar PV resources reducing power output (either due to momentary cessation or inverter tripping) as a result of normally-cleared [Bulk-Power System] faults. The widespread nature of power reduction across many

facilities poses risks to [Bulk-Power System] performance and reliability.”).

14. Simulations conducted by the NERC Resource Subcommittee demonstrate that the risks to Bulk-Power System reliability posed by momentary cessation are greater than any of the actual IBR disturbances that NERC has documented since 2016.

These simulations indicate the potential for: (1) normally-cleared, three-phase faults at certain locations in the Western Interconnection to result in upwards of 9,000 MW of solar PV IBRs entering momentary cessation across a large geographic region; (2) transient instability caused by excessive transfer of inter-area power flows during and after momentary cessation; and (3) a drop in frequency that falls below the first stage of under frequency load shedding in the Western Electricity Coordinating Council (WECC) region (traditionally studied as the loss of the two Palo Verde nuclear units in Arizona, which total approximately 2,600 MW). These simulation results indicate that IBR momentary cessation occurring in the aggregate can lead to instability, system-wide uncontrolled separation, and voltage collapse.

See

NERC,

Resource Loss Protection Criteria Assessment,

(Feb. 2018),

https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/IRPTF_RLPC_Assessment.pdf

Id.

at 1-2, key findings 4, 7, 8.

15. Although IBRs present risks that Bulk-Power System planners and operators must account for, IBRs also present new opportunities to support the grid and respond to abnormal grid conditions.

When appropriately programmed, IBRs can operate during greater frequency deviations (

i.e.,

a wider frequency range) than synchronous generation resources.

This operational flexibility—and the ability of IBRs to perform with precision, speed, and control—could mitigate disturbances on the Bulk-Power System. For Bulk-Power System operators to harness the unique performance and control capabilities of IBRs, these resources must be properly configured and programmed to support grid voltage and frequency during normal and abnormal grid conditions and must be accurately modeled and represented in transmission planning and operations models.

See, e.g.,

IBR Performance Guideline at vii (finding that the power electronics aspects of IBRs “present new opportunities in terms of grid control and response to abnormal grid conditions.”).

See, e.g.,

Fast Frequency Response White Paper at 11.

C. Notice of Proposed Rulemaking

16. On November 17, 2022, the Commission issued the NOPR in this proceeding, proposing to direct NERC to submit new or modified Reliability Standards addressing four gaps in the currently effective Reliability Standards pertaining to IBRs: (1) data sharing; (2) model validation; (3) planning and operational studies; and (4) performance requirements.

The Commission initiated this action in light of the rapid change in the generation resource mix currently underway on the Bulk-Power System and the projected addition of unprecedented numbers of IBRs to the Bulk-Power System.

The Commission noted that IBRs provide many benefits, but that IBRs also present new considerations for transmission planning and operation of the Bulk-Power System.

NOPR, 181 FERC ¶ 61,125 at P 1.

Id.

P 2 (citing 2020 LTRA Report).

Id.

17. The Commission proposed to direct NERC to address the four reliability gaps by developing one or more new Reliability Standards or modifying the currently effective Reliability Standards. The Commission did not propose specific requirements; instead, the Commission identified concerns that the Reliability Standards should address. The Commission sought comments on its identified concerns and whether there were other concerns related to planning for and integrating IBRs that the Commission should direct NERC to address in this or a future proceeding.

Id.

P 6.

18. First, the Commission proposed to direct NERC to develop new or modified Reliability Standards addressing IBR data sharing. The Commission proposed that the new or modified Reliability Standards should ensure that NERC registered entities

have the necessary data to predict the behavior of all IBRs, including registered and unregistered IBRs individually and in the aggregate, and IBR-DERs in the aggregate, and their impact on the reliable operation of the Bulk-Power System. The Commission stated that the new or modified Reliability Standards should ensure that generator owners, transmission owners, and distribution providers are required to share validated modeling, planning, operations, and disturbance monitoring data for registered and unregistered IBRs and IBR-DERs in the aggregate with planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities.

NERC identifies and registers Bulk-Power System users, owners, and operators who are responsible for performing specified reliability functions to which requirements of mandatory Reliability Standards are applicable.

See

NERC,

Rules of Procedure,

Section 500 (Organization Registration and Certification) (Aug. 25, 2022),

https://www.nerc.com/AboutNERC/RulesOfProcedure/NERC%20ROP%20effective%2020220825_with%20appendicies.pdf

NOPR, 181 FERC ¶ 61,125 at P 5.

19. Second, the Commission proposed to direct NERC to develop new or modified Reliability Standards addressing IBR model validation. The Commission proposed that the new or modified Reliability Standards should ensure that IBR models are comprehensive, validated, and updated in a timely manner, so that they can adequately predict the behavior of registered and unregistered IBRs individually and in the aggregate, and IBR-DERs in the aggregate, and their impacts on the reliable operation of the Bulk-Power System.

Id.

20. Third, the Commission proposed to direct NERC to develop new or modified Reliability Standards addressing IBR planning and operational studies. The Commission proposed to direct that the new or modified Reliability Standards ensure that validated IBR models are included in transmission planning and operational studies to assess the reliability impacts on Bulk-Power System performance by registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate. The Commission stated that the Reliability Standards should ensure that planning and operational studies assess the impacts of registered and unregistered IBRs individually and in the aggregate, and IBR-DERs in the aggregate, within and across planning and operational boundaries for normal operations and contingency event conditions.

Id.

21. Fourth, the Commission proposed to direct NERC to develop new or modified Reliability Standards addressing IBR performance requirements.

The Commission explained that the new or modified Reliability Standards should require that registered IBRs provide frequency and voltage support during frequency and voltage excursions, including post-disturbance ramp rates and phase lock

loop synchronization, in a manner necessary to contribute toward meeting the overall system needs for essential reliability services.

Further, the Commission stated that the new or modified Reliability Standards should establish clear and reliable technical limits and capabilities for registered IBRs to ensure that all registered IBRs are operated in a predictable and reliable manner during both normal operations and contingency event conditions.

Id.

(citing Essential Reliability Services Concept Paper at vi).

22. Finally, the Commission proposed to direct NERC to submit a compliance filing within 90 days of the effective date of the final action in this proceeding. The Commission proposed to direct NERC to include in its compliance filing a detailed, comprehensive standards development and implementation plan explaining how NERC will prioritize the development and implementation of new or modified Reliability Standards. The Commission stated that NERC should explain how it would prioritize its IBR Reliability Standard projects to meet the directives in the final action, taking into account the risk posed to the reliability of the Bulk-Power System, standard development projects already underway, resource constraints, and other factors if necessary.

Id.

P 7.

23. The comment period for the NOPR ended on February 6, 2023, with reply comments due on March 6, 2023. The Commission received 18 initial comments and 3 reply comments.

A list of commenters to the NOPR and the abbreviated names used in this final action appear in Appendix A. Interventions are not necessary to file comments in a rulemaking. Nevertheless, Acciona Energy USA Global LLC, Cordelio USA, Inc., Electricity Consumers Resource Council, the Federal Energy Advocate, the Public Utilities Commission of Ohio, Georgia Transmission Corporation, GlidePath Development, LLC, Monitoring Analytics, LLC, and Old Dominion Electric Cooperative filed motions to intervene.

III. Need for Reform

24. As the Commission explained in the NOPR, a number of events have demonstrated the challenges to transmission planning and operations of the Bulk-Power System posed by gaps in the Reliability Standards specific to IBRs.

In this final action, we continue to find that as the resource mix trends towards higher penetrations of IBRs, the need to reliably integrate these resources into the Bulk-Power System is expected to grow, and that the currently effective Reliability Standards do not adequately address IBR reliability risks.

The continuing risks that the increasing penetration of IBRs pose to the reliable operation of the Bulk-Power System underscore the need for mandatory Reliability Standards to address these issues on a nationwide basis.

See

NOPR, 181 FERC ¶ 61,125 at PP 24-26.

Id.

PP 26-27.

25. NERC, groups such as the Institute of Electrical and Electronics Engineers (IEEE), and other entities have attempted to address IBR-related reliability concerns at the manufacturer, state, local, or individual entity level over the past several years.

While the various ongoing IBR-related projects are important efforts, the absence of a comprehensive plan to require that the increasing numbers of IBRs are reliably interconnected, planned for, and operated on the Bulk-Power System limits those individual projects' overall impact. Moreover, these individual efforts could lead to inconsistent results that fail to fully address the gaps identified herein, a concern that could be resolved by addressing all IBR issues through the Reliability Standards. Therefore, to help ensure that a broader range of reliability concerns related to the impacts of IBRs on the Bulk-Power System are addressed, that any necessary new requirements apply nationwide, and that any new rules are mandatory, we find that it is imperative for NERC to develop new or modified Reliability Standards as directed in this final action to address reliability concerns related to IBRs at all stages of interconnection, planning, and operations. However, we note that the directives to NERC in this final action are intended to complement other ongoing NERC and Commission actions to address the impacts of all IBRs on the Bulk-Power System, as well as existing voluntary efforts underway, and are not intended to supersede or interfere with these efforts.

For example, to address gaps in data and model validation and to facilitate sharing and combining of neighboring planning models, ISO New England (ISO-NE) has taken steps to retire obsolete and unapproved models within its own footprint.

See

ISO-NE,

Generator Data Submittal Requirements—Planning, Topic Retiring Obsolete and NERC Non-Approved Models,

121-125 (Jan. 24, 2023),

https://www.iso-ne.com/static-assets/documents/2023/01/20230124-gen-data-submittal-requirements-planning.pdf.

A. Current Actions Are Insufficient To Address IBR Reliability Risks

26. As explained in the NOPR, at least 12 documented events on the Bulk-Power System

show IBRs acting unexpectedly and adversely in response to normally cleared transmission line faults on the Bulk-Power System, each highlighting one or more common mode failures of IBRs of various sizes and voltage connection levels.

The 12 events report an average of approximately 1,000 MW of IBRs entering into momentary cessation or tripping in the aggregate. The 12 Bulk-Power System events are: (1) the Blue Cut Fire (August 16, 2016); (2) the Canyon 2 Fire (October 9, 2017); (3) Angeles Forest (April 20, 2018); (4) Palmdale Roost (May 11, 2018); (5) San Fernando (July 7, 2020); (6) the first Odessa, Texas event (May 9, 2021); (7) the second Odessa, Texas event (June 26, 2021); (8) Victorville (June 24, 2021); (9) Tumbleweed (July 4, 2021); (10) Windhub (July 28, 2021); (11) Lytle Creek (August 26, 2021); and (12) Panhandle Wind Disturbance (March 22, 2022).

NOPR, 181 FERC ¶ 61,125 at P 4.

27. In addition to those 12 documented events discussed in the NOPR, on June 4, 2022, an IBR-related disturbance near Odessa, Texas (the third in this location) occurred. During this disturbance, a normally cleared single-line-to-ground fault resulted in a total loss of 2,555 MW of synchronous and IBR generation, and system frequency dropped to 59.7 Hz.

This is the largest (to date) NERC-recorded IBR-related disturbance event and the total loss of generation resources was one and half times larger than the average loss of the 12 preceding reported events. The NERC and Texas Reliability Entity, Inc. (Texas RE) joint report, issued in December 2022, explains that this event is significant because the size of this disturbance nearly exceeded the Texas Interconnection Resource Loss Protection Criteria (

i.e.,

2,750 MW) defined in Reliability Standard BAL-003-2,

which is used to establish the largest credible contingency for frequency stability in an interconnection.

A power system deviating from 60 Hz indicates there is a generation and load imbalance. When the generation loss is too large, automatic under-frequency load shedding is used to rebalance the power system to prevent cascading failures that lead to blackouts. In Texas, the automatic under-frequency load shed (UFLS) program is set to trigger a sudden loss of load at 59.3 Hz.

See generally

Public Utility Commission of Texas,

Load Shed Protocols for the Electric Reliability Council of Texas (ERCOT) Region,

(Aug. 31, 2022),

https://ftp.puc.texas.gov/public/puct-info/agency/resources/reports/leg/PUC_Load_Shed_Protocols_Study.pdf. See also

NERC Newsroom Announcement

Odessa Disturbance Illustrates Need for Immediate Industry Action on Inverter-Based Resources

(Dec. 8, 2022),

https://www.nerc.com/news/Headlines%20DL/OdessaDisturbance_08DEC22.pdf

(explaining that “[t]he 2022 Odessa disturbance was a Category 3a event in the NERC Event Analysis Process, and the combined loss of generation nearly exceeded the Texas Interconnection Resource Loss Protection Criteria.”).

See

Reliability Standard BAL-003-2 (Frequency Response and Frequency Bias Setting), attach. A.

NERC and Texas RE,

2022 Odessa Disturbance,

v (Dec. 2022),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/NERC_2022_Odessa_Disturbance_Report%20(1).pdf

(Odessa 2022

Disturbance Report) (covering events in Odessa, Texas on June 4, 2022).

28. In response to the multiple Odessa, Texas disturbances, NERC issued its third level 2 alert on IBR performance issues on March 14, 2023.

In the alert, NERC states its level 2 alert is necessary because the disturbances in Odessa, Texas, showed that solar PV IBR resources exhibited “systemic performance issues” with the potential to cause widespread outages on the Bulk-Power System.

Although the NERC alert pertains specifically to solar PV resources, the alert recommendations may be applicable to Bulk-Power System connected battery energy storage systems. Further, NERC explains that as the penetration of Bulk-Power System-connected IBRs increases, it will be necessary to address performance deficiencies in an “effective and efficient manner.”

In the March 2023 Alert, NERC sought to gather information from registered generator owners of solar-PV (

i.e.,

IBRs) and to encourage them to implement recommendations to: (1) ensure inverter protection settings, collector system settings, and substation settings are updated or changed to mitigate inadvertent operations; and (2) ensure that facility control modes, fault ride through modes and parameters, and protections are set and coordinated to facilitate Bulk-Power System voltage and frequency ride through.

NERC,

Industry Recommendation: Inverter-Based Resource Performance Issues

(Mar. 2023),

https://www.nerc.com/pa/rrm/bpsa/Alerts%20DL/NERC%20Alert%20R-2023-03-14-01%20Level%202%20-%20Inverter-Based%20Resource%20Performance%20Issues.pdf

(March 2023 Alert).

See

NOPR, 181 FERC ¶ 61,125 at P 18 (explaining that the level 2 alerts recommend specific voluntary action to be taken by registered IBRs).

March 2023 Alert at 1.

Id.

29. NERC also recently issued another disturbance report covering events in Southwest Utah in the morning of April 10, 2023.

NERC explains that the causes of the Southwest Utah disturbance are similar to past solar PV IBR-related events.

NERC identifies this event as the “first major widespread solar [PV] loss to occur in the Western Interconnection outside of California.”

NERC and WECC,

2023 Southwest Utah Disturbance

(Aug. 2023),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/NERC_2023_Southwest_UT_Disturbance_Report.pdf

(Southwest Utah Disturbance Report).

Id.

at iv.

Id.

30. NERC has found that distributed energy resources' (

i.e.,

IBR-DERs') responses to Bulk-Power-System disturbances can cause short term net load increases likely attributed to aggregate IBR-DERs tripping.

This behavior and the resulting net load increases can impact Bulk-Power-System performance.

Multiple Solar PV Disturbances in CAISO: Disturbances between June and August 2021 Joint NERC and WECC Staff Report, 17-18, (Apr. 2022),

https://www.nerc.com/pa/rrm/ea/Documents/NERC_2021_California_Solar_PV_Disturbances_Report.pdf.

San Fernando Disturbance: Southern California Event: July 7, 2020 Joint NERC and WECC Staff Report,

12 (Nov. 2020),

https://www.nerc.com/pa/rrm/ea/Documents/San_Fernando_Disturbance_Report.pdf.

31. NERC has also issued two recent IBR-related Reliability Guidelines. In February 2023 NERC issued an updated guideline on aggregate DER modeling (DER_A model),

and in March 2023, NERC issued its first guideline on electromagnetic transient (EMT) modeling and studies for IBRs.

NERC,

Reliability Guideline: Parameterization of the DER_A Model for Aggregate DER

(Feb. 2023),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Reliability_Guideline_ModelingMerge_Responses_clean.pdf

(2023 DER_A Model Guideline). The DER_A model is the approved steady state and dynamic model that industry has validated and maintained to model IBR-DERs in the aggregate and used to study the potential impacts of IBR-DERs in the aggregate on the Bulk-Power System. The term “parameterize” means to adjust the parameter values of a generic model to best reflect the dynamic characteristics of a user-defined model. The parameterization process aims at reducing the difference (error) between the dynamic responses of both the generic and user-defined models.

See, e.g.,

Energy Systems Integration Group,

Parameterization,

https://www.esig.energy/wiki-main-page/parameterization-d1/.

NERC,

Reliability Guideline: Electromagnetic Transient Modeling for BPS-Connected Inverter-Based Resources—Recommended Model Requirements and Verification Practices

(Mar. 2023),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Reliability_Guideline-EMT_Modeling_and_Simulations.pdf

(EMT Modeling Guideline).

32. NERC also has nine separate projects underway to update its currently effective Reliability Standards relevant to IBRs; however, these projects are still in their early stages and, even if they are completed, the results of these efforts may not fully address the reliability risks that IBRs pose to the Bulk-Power System described above.

The current NERC standards development projects underway include: (1) Project 2021-04 (Modifications to PRC-002-2) to ensure that disturbance monitoring data is available and provided by generator owners of IBR facilities; (2) Project 2020-06 (Verifications of Models and Data for Generators) to enhance requirements for model verification; (3) Project 2022-04 (EMT Modeling) to address the inclusion of EMT modeling and studies in relevant Reliability Standards; (4) Project 2022-02 (Modifications to TPL-001-5.1 and MOD-032-1) addressing certain issues regarding appropriate inclusion of IBRs and DERs in planning assessments; (5) Project 2020-02 (Modifications to PRC-024 (Generator Ride-through)) to revise or replace current Reliability Standard PRC-024-3 with a standard that will require ride through performance from all generation resources; (6) Project 2023-02 (Performance of IBRs) to address post-event performance validation ensuring that resources perform the way they are expected or required to perform; (7) Project 2021-01 (Modifications to MOD-025 and PRC-019) to ensure that plant active and reactive power capabilities are accurately provided to planning entities for use in studies; (8) Project 2021-02 (Modifications to VAR-002-4.1) to clarify whether the generator operator of a dispersed power resource must notify its associated transmission operator upon a status change of a voltage controlling device on an individual generating unit; and (9) Project 2023-01 (EOP-004 IBR Event Reporting) to ensure timely reporting of events involving IBRs.

See

NERC,

Reliability Standards Under Development, https://www.nerc.com/pa/Stand/Pages/Standards-Under-Development.aspx.

33. While we recognize NERC's ongoing efforts, systemic fault ride through deficiencies continue to result in IBRs displaying unexpected and abnormal performance during grid disturbances.

In fact, in the March 2023 Alert, NERC states that IBR-related issues continue to occur and has announced plans to issue an alert by the end of 2023 regarding IBR modeling issues.

March 2023 Alert at 6-7.

Id.

at 6.

34. The Commission has also been actively addressing ongoing IBR-related concerns. Concurrently with the NOPR, the Commission issued an order directing NERC to identify and register owners and operators of unregistered IBRs that in the aggregate have a material impact on the reliable operation of the Bulk-Power System.

On February 15, 2023, as amended on March 13, 2023, NERC submitted its compliance filing, which included its work plan setting out NERC's planned activities and milestones to register generator owners and operators of IBRs. On May 18, 2023, the Commission approved NERC's work plan and associated implementation milestones.

See

IBR Registration Order, 181 FERC ¶ 61,124 at P 6.

N. Am. Elec. Reliability Corp.,

183 FERC ¶ 61,116 (2023) (Order Approving Workplan). On August 16, 2023, NERC submitted its first progress update on its registration workplan.

See

NERC, Filing, Docket No. RD22-4-001 (filed Aug. 16, 2023).

35. The Commission also recently revised the

pro forma

Large Generator Interconnection Procedures (LGIP), the

pro forma

Large Generator Interconnection Agreement (LGIA), the

pro forma

Small Generator Interconnection Procedures (SGIP), and the

pro forma

Small Generator Interconnection Agreement (SGIA) in Order No. 2023.

Some of those revisions address identified deficiencies

with respect to IBR modeling and ride through performance by requiring that newly interconnecting non-synchronous generators (

i.e.,

IBRs) (1) submit accurate and verified models with a comparable level of accuracy as synchronous generation resources and (2) configure or set control and protection settings to ride through disturbances and continue to support system reliability during abnormal frequency conditions and voltage conditions within any physical limitations of the generating facility.

See Improvements to Generator Interconnection Agreements & Procs.,

Order No. 2023, 88 FR 61014 (Sept. 6, 2023), 184 FERC ¶ 61,054 (2023).

Id.

PP 1661, 1715.

36. In addition to NERC and Commission efforts, there are several voluntary industry standards and manufacturer certification efforts related to IBRs, such as the IEEE standard 2800-2022

for transmission connected IBRs and IEEE standard 1547-2018

and Underwriters Laboratory (UL) standard UL 1741

for distributed energy resources. These efforts are intended to enhance the operating performance and control capabilities of IBRs; however, these efforts do not apply to all relevant IBRs and require adoption by state or other regulatory authorities to become mandatory and enforceable.

IEEE,

Standard for Interconnection and Interoperability of Inverter-Based Resources (IBR) Interconnecting with Associated Transmission Electric Power Systems

(Apr. 22, 2022),

https://standards.ieee.org/ieee/2800/10453/

(IEEE 2800-2022) (establishing uniform technical minimum requirements for the interconnection, capability, and performance of IBRs for reliable integration onto the Bulk-Power System).

IEEE,

Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces

(Feb. 15, 2018),

https://standards.ieee.org/ieee/1547/5915/

(IEEE 1547-2018). The IEEE 1547-2018 and more recent 2020 amendment (IEEE 1547a-2020) of this standard enhance operating performance and control capabilities of IBR-DERs. For example, IBR-DERs compliant with the IEEE standard will be equipped with the capability to ride through voltage and frequency fluctuations in support of the reliable operation of the Bulk-Power System.

UL Standard 1741 Edition 3,

Inverters, Converters, Controllers and Interconnection System Equipment for Use with Distributed Energy Resources Scope, https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=40673.

The IEEE Standards Association's board approved IEEE-2800-2022 in September 2022.

See

IEEE,

IEEE Standard for Interconnection and Interoperability of Inverter-Based Resources (IBRs) Interconnecting with Associated Transmission Electric Power Systems, https://standards.ieee.org/ieee/2800/10453/

(explaining that IEEE-2800-2022 establishes uniform technical minimum requirements for the interconnection, capability, and lifetime performance of IBRs interconnecting with transmission and sub-transmission systems in North America). For IEEE-1547, states have made varied progress in adopting the standard.

See

IEEE,

IEEE Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces, https://sagroups.ieee.org/scc21/standards/1547rev/;

see also

Odessa 2022 Disturbance Report at v (explaining that the 2022 Odessa Disturbance “is a perfect illustration of the need for immediate industry action to ensure reliable operation of the [Bulk-Power System] with increasing penetrations of inverter-based resources.”).

B. Existing Reliability Standards Do Not Adequately Address IBR Reliability Risks

1. Data Sharing

37. The currently effective Reliability Standards do not require owners and/or operators of registered IBRs, transmission owners that have unregistered IBRs on their systems, or distribution providers that have IBR-DERs on their systems to provide planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities with data that accurately represents IBRs. Examples of needed data may include location; capacity; telemetry; steady-state, dynamic, and short circuit modeling information; control settings; ramp rates; equipment status; and disturbance analysis data.

Data that accurately represents IBRs is necessary to properly plan for, operate, and analyze IBR performance on the Bulk-Power System.

Without data that accurately represents all IBRs, planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities are not able to develop system models that accurately account for the behavior of IBRs on their system, nor are they able to facilitate the analysis of Bulk-Power System disturbances.

NOPR, 181 FERC ¶ 61,125 at P 27.

NERC has provided examples of necessary planning and operational IBR data.

See, e.g.,

NERC,

Industry Recommendation: Loss of Solar Resources during Transmission Disturbances due to Inverter Settings—II,

7-8 (May 2018),

https://www.nerc.com/pa/rrm/bpsa/Alerts%20DL/NERC_Alert_Loss_of_Solar_Resources_during_Transmission_Disturbance-II_2018.pdf

(Loss of Solar Resources Alert II) (describing examples of planning and operational IBR data); NERC and Texas RE,

Odessa Disturbance,

20-21 (Sept. 2021),

https://www.nerc.com/pa/rrm/ea/Documents/Odessa_Disturbance_Report.pdf

(Odessa 2021 Disturbance Report) (covering events in Odessa, Texas on May 9, 2021 and June 26, 2021);

see generally

NERC and WECC,

WECC Base Case Review: Inverter-Based Resources

(Aug. 2020),

https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/NERC-WECC_2020_IBR_Modeling_Report.pdf

(Western Interconnection Base Case IBR Review); NERC,

Reliability Guideline: DER Data Collection for Modeling in Transmission Planning Studies

(Sept. 2020),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Reliability_Guideline_DER_Data_Collection_for_Modeling.pdf

(IBR-DER Data Collection Guideline).

NOPR, 181 FERC ¶ 61,125 at P 28.

38. While Reliability Standard MOD-032-1 (Data for Power System Modeling and Analysis), Requirement R2 requires generator owners to submit modeling data and parameters to their transmission planners and planning coordinators, it does not require generator owners to submit registered IBR-specific modeling data and parameters such as control settings for momentary cessation and ramp rates, which are necessary for modeling steady state and dynamic registered IBR performance for purposes of planning the Bulk-Power System.

Nor does Reliability Standard TOP-003-5 (Operational Reliability Data) require generator owners to submit such registered IBR-specific modeling data and parameters to their transmission operators or balancing authorities.

See

NERC,

Technical Report, BPS-Connected Inverter-Based Resource Modeling and Studies,

35 (May 2020),

https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/IRPTF&_IBR_Modeling_and_Studies_Report.pdf

(Modeling and Studies Report) (stating that Reliability Standard MOD-032-1 “does not prescribe the details that the modeling requirements must cover; rather, the standard requirements leave the level of detail and data formats up to each [transmission planner] and [planning coordinator] to define.”) (footnote omitted).

See

NOPR, 181 FERC ¶ 61,125 at P 29 (referring to Reliability Standard TOP-003-4, the version of the standard enforceable at that time. Reliability Standard TOP-003-5 became mandatory and enforceable on April 1, 2023).

39. Moreover, the currently effective Reliability Standards do not ensure that Bulk-Power System planners and operators receive disturbance monitoring data regarding all generation resources capable of having a material impact on the reliable operation of the Bulk-Power System, including registered IBRs. Such data is needed to adequately assess disturbance events (

e.g.,

a fault on the line) and the behavior of IBRs during those events. Without adequate monitoring capability, the disturbance analysis data for a system event is insufficient to effectively determine the causes of the system event.

NERC and WECC,

Multiple Solar PV Disturbances in CAISO,

13 (Apr. 2022),

https://www.nerc.com/pa/rrm/ea/Documents/NERC_2021_California_Solar_PV_Disturbances_Report.pdf

(2021 Solar PV Disturbances Report) (covering four events: Victorville (June 24, 2021); Tumbleweed (July 4, 2021); Windhub (July 28, 2021); and Lytle Creek (August 26, 2021)) (explaining that the “analysis team had significant difficulty gathering useful information for root cause analysis at multiple facilities . . . [and] this led to an abnormally large number of `unknown' causes of power reduction for the plants analyzed”).

40. Limitations on the availability of event data have hampered efforts by NERC, stakeholders, and industry to determine the causes of various events since 2016. In many instances, data were limited and disturbance monitoring equipment was absent because registered IBRs interconnected at lower voltages and fell below the

MVA threshold.

These IBRs therefore did not fall within the thresholds of the currently effective Reliability Standard PRC-002-2 (Disturbance Monitoring and Reporting Requirements) Attachment 1 requirements for equipment installation.

Further, the absence of adequate monitoring capability leads to the potential for unreliable operation of generation resources due to the inability to effectively gather disturbance analysis data and develop mitigation strategies to either avoid or recover from abnormal resource performance during disturbance events in the future. While Reliability Standard PRC-002-2 requires the installation of disturbance monitoring equipment at certain key nodes (

e.g.,

stability limited interfaces), and such limited placements have been adequate to provide the data necessary to analyze major system events in the past, NERC has found that the existing disturbance monitoring equipment is not sufficient (

e.g.,

lack of high speed data captured at the IBR or plant level controller and low resolution time stamping of inverter sequence of event recorder information) to analyze the widespread system events that have become more common since 2016.

NERC,

Improvements to Interconnection Requirements for BPS-Connected Inverter-Based Resources,

at 1 (Sept. 2019) (IBR Interconnection Requirements Guideline) (reporting that the majority of newly interconnecting IBRs are either connecting at voltages less than 100 kV or with capacity less than 75 MVA and therefore do not meet the size criteria in the bulk electric system definition). NERC's Commission-approved bulk electric system definition is a subset of the Bulk-Power System and defines the scope of the Reliability Standards and the entities subject to NERC compliance.

Revisions to Electric Reliability Org. Definition of Bulk Elec. Sys. & Rules of Proc.,

Order No. 773, 141 FERC ¶ 61,236 (2012)

order on reh'g,

Order No. 773-A (May 17, 2013), 143 FERC ¶ 61,053 (2013),

rev'd sub nom. People of the State of N.Y.

FERC,

783 F.3d 946 (2d Cir. 2015); NERC Glossary at 7-9.

NOPR, 181 FERC ¶ 61,125 at P 32;

see also

Reliability Standard PRC-002-2, Requirement R5.1.1 (specifying dynamic disturbance recording data for generation resource(s) with gross individual nameplate rating greater than or equal to 500 MVA, and gross individual nameplate rating greater than or equal to 300 MVA where the gross plant/facility aggregate nameplate rating is greater than or equal to 1,000 MVA).

See

NOPR, 181 FERC ¶ 61,125 at P 32 n.74 (citing NERC and WECC,

April and May 2018 Fault Induced Solar Photovoltaic Resource Interruption Disturbances Report,

23 (Jan. 2019),

https://www.nerc.com/pa/rrm/ea/April_May_2018_Fault_Induced_Solar_PV_Resource_Int/April_May_2018_Solar_PV_Disturbance_Report.pdf

(Angeles Forest and Palmdale Roost Events Report) (covering the Angeles Forest (April 20, 2018) and Palmdale Roost (May 11, 2018) events and explaining that the “widespread nature of power reduction across many facilities poses risks to [Bulk-Power System] performance and reliability” and finding that the “lack of available high-speed data at multiple inverter-based resources has hindered event analysis”); San Fernando Disturbance Report at 7; Odessa 2021 Disturbance Report at 11; NERC,

Odessa Disturbance Follow-up White Paper

(Oct. 2021),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/White_Paper_Odessa_Disturbance_Follow-Up.pdf

(Odessa Disturbance White Paper)).

41. The currently effective Reliability Standards do not require Bulk-Power System planners and operators to receive modeling data and parameters regarding unregistered IBRs that, individually or in the aggregate, are capable of adversely affecting the reliable operation of the Bulk-Power System. Further, the currently effective Reliability Standards do not require that Bulk-Power System planners and operators receive modeling data and parameters that accurately represent IBR-DERs that in the aggregate have a material impact on the reliable operation of the Bulk-Power System.

As shown by various reports and guidelines,

Bulk-Power System planners and operators do not currently have the data to accurately model the behavior of registered and unregistered IBRs individually and in the aggregate, and IBR-DERs in the aggregate, for steady-state, dynamic, and short circuit studies.

See

NOPR, 181 FERC ¶ 61,125 at P 80 (stating that distribution providers should be permitted to provide IBR-DER modeling data and parameters “in the aggregate or equivalent for IBR-DERs interconnected to their distribution systems (

e.g.,

IBR-DERs in the aggregate and modeled by resource type such as wind or solar PV, or IBR-DERs in the aggregate and modeled by interconnection requirements performance to represent different steady-state and dynamic behavior.”);

see also

IBR-DER Data Collection Guideline at 2 (recommending that transmission planners and planning coordinators update their data reporting requirements for Reliability Standard MOD-032-1, Requirement R1 to explicitly describe the requirements for aggregate IBR-DER data in a manner that is clear and consistent with their modeling practices. The IBR-DER Data Collection Guideline also recommended that transmission planners and planning coordinators establish modeling data requirements for steady-state IBR-DERs in aggregate and coordinate with their distribution providers to develop these requirements.).

2. Data and Model Validation

42. Bulk-Power System planners and operators need accurate planning, operations, and interconnection-wide models to ensure the reliable operation of the Bulk-Power System. Bulk-Power System planners and operators use electrical component models to build the generation, transmission, and distribution facility models that they combine to build their transmission area model. These models are further combined with those of their neighbors to form the interconnection-wide models, which are used to analyze the reliability of the interconnected transmission system.

Each of the planning, operations, and interconnection-wide models consist separately of steady state, dynamic, and short circuit models.

See

Reliability Standard MOD-033-2 (Steady-State and Dynamic System Model Validation).

43. Without planning, operations, and interconnection-wide models that accurately reflect resource (

e.g.,

generation and load) behavior in steady state and dynamic conditions, Bulk-Power System planners' and operators' system models

are unable to adequately predict resource behavior, including momentary cessation from both registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate, and their subsequent impacts on the Bulk-Power System.

This final action uses the term “system models” to refer collectively to planning and operations transmission area models and interconnection-wide models.

See

IBR Interconnection Requirements Guideline at 24 (stating that a systemic modeling issue was uncovered regarding the accuracy of the IBR dynamic models submitted in the interconnection-wide base cases following the issuance of the NERC Alert related to the Canyon 2 Fire disturbance).

44. The currently effective Reliability Standards do not require the use of NERC's approved component models;

instead, models are referred to generally in Reliability Standard MOD-032-1, Attachment 1.

Without requirements to use approved component models in Bulk-Power System planning and operations system models, resource

owners may provide modeling data that is based on a user-defined model

rather than an approved and industry-vetted model.

The use of user-defined models in system models can be problematic because their internal model components cannot be viewed or modified, and thus they produce outputs that cannot be readily explained or verified.

Approved generator models that accurately reflect the generator behavior in steady state and dynamic conditions are necessary for Bulk-Power System planners and operators to adequately predict IBR behavior and the subsequent impact of IBRs on the Bulk-Power System.

NERC,

Libraries of Standardized Powerflow Parameters and Standardized Dynamics Models version 1,

1 (Oct. 2015),

https://www.nerc.com/comm/PC/Model%20Validation%20Working%20Group%20MVWG%202013/NERC%20Standardized%20Component%20Model%20Manual.pdf

(NERC Standardized Powerflow Parameters and Dynamics Models) (explaining that the NERC Modeling Working Group was tasked to develop, validate, and maintain a library of standardized component models and parameters for short-circuit, powerflow, and dynamics cases. The standardized models in these libraries have documentation describing their model structure, parameters, and operation. This information has been vetted by the industry and thus deemed appropriate for widespread use in planning, operations, and interconnection-wide analysis.).

See

Reliability Standard MOD-032-1, attach. 1 (explaining that if a user-written model(s) is submitted in place of a generic or library model, it must include the characteristics of the model, including block diagrams, values, and names for all model parameters, and a list of all state variables).

Some commenters use the term “proprietary” to describe user-defined models. For purposes of this final action, the terms “proprietary” and “user-defined” models are synonymous. A user-defined model is a unique manufacturer-specific model that does not appear on the NERC approved component model list. In Order No. 2023, the Commission defined a “user-defined model” as any set of programming code created by equipment manufacturers or developers that captures the latest features of controllers that are mainly software-based and represents the entities' control strategies but does not necessarily correspond to any particular generic library model.

See

Order No. 2023, 184 FERC ¶ 61,054 at P 1660.

NERC Standardized Powerflow Parameters and Dynamics Models at 1 (explaining that “[s]ome of the model structures have information that is considered to be proprietary or confidential, which impedes the free flow of information necessary for interconnection‐wide power system analysis and model validation.”);

see also

NERC,

Events Analysis Modeling Notification Recommended Practices for Modeling Momentary Cessation Initial Distribution,

1 n.4 (Feb. 2018),

https://www.nerc.com/comm/PC/NERCModelingNotifications/Modeling_Notification_-_Modeling_Momentary_Cessation_-_2018-02-27.pdf

(explaining that more detailed vendor-specific models may be used for local planning studies; however, they are generally not allowed or recommended for building interconnection-wide models).

See, e.g.,

EPRI,

Model User Guide for Generic Renewable Energy System,

2 (June 2015),

https://www.epri.com/research/products/000000003002006525

(explaining that the “models presented here were developed primarily for the purpose of general public use and benefit and to eliminate the long standing issues around many vendor-specific models being proprietary and thus neither publicly available nor easily disseminated among the many stakeholders. Furthermore, using multiple user-defined non-standard models within large interconnection studies, in many cases, presented huge challenges and problems with effectively and efficiently running the simulations.”).

NERC Standardized Powerflow Parameters and Dynamics Models at 1 (explaining that there is a growing need for accurate interconnection‐wide power flow and dynamics simulations that analyze phenomena such as: frequency response, inter-area oscillations, and interactions between the growing numbers of wide-area control and protections systems).

45. Any generation resource model's performance must be verified by the generator owner using real-world data to confirm that the generation resource model adequately reflects actual as-built settings, historic performance, and/or field-testing data.

100

The currently effective Reliability Standards MOD-026-1 (Verification of Models and Data for Generator Excitation Control System or Plant Volt/Var Control Functions)

101

and MOD-027-1 (Verification of Models and Data for Turbine/Governor and Load Control or Active Power/Frequency Control Functions)

102

require each generator owner to verify models and data for specific components of synchronous resources (

e.g.,

generator excitation control systems, plant volt/var control functions, turbine/governor and load controls, and active power/frequency controls), but they do not require a generator owner to provide verified models and data for IBR-specific controls (

e.g.,

power plant central controller functions and protection system settings) to its transmission planner. Additionally, the currently effective Reliability Standards neither require the transmission owner for unregistered IBRs to provide verified dynamic models nor require distribution providers to provide verified dynamic models of IBR-DERs in the aggregate to their transmission planners. Finally, the currently effective Reliability Standards neither require the transmission owner for unregistered IBRs nor the distribution providers for IBR-DERs in the aggregate to submit the respective dynamic models to the applicable registered entities that perform planning and operations functions.

100

Id.

(explaining that the NERC Modeling Working Group was tasked to develop, validate, and maintain a library of standardized component models and parameters for powerflow and dynamics cases. The standardized models in these libraries have documentation describing their model structure, parameters, and operation. This information has been vetted by the industry and thus deemed appropriate for widespread use in interconnection‐wide analysis).

101

See

Reliability Standard MOD-026-1.

102

See

Reliability Standard MOD-027-1.

46. Once the generator owners for registered IBRs, transmission owners for unregistered IBRs, and distribution providers for IBR-DERs in the aggregate verify plant models, Bulk-Power System planners and operators must validate and update system models (

i.e.,

planning and operation transmission area models as well as interconnection-wide models) by comparing the provided data and resulting system models against actual system operational behavior. While Reliability Standard MOD-033-2 (Steady State and Dynamic System Model Validation) requires validation using real-world data of the interconnection-wide model,

103

the currently effective Reliability Standards lack clarity as to whether models of registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate are required to represent the real-world behavior of the equipment installed in the field during interconnection-wide disturbances that have exhibited common mode failures of IBRs.

104

103

Reliability Standard MOD-033-2, Requirements R1, R2.

104

NERC annually assesses the interconnection-wide model quality and publishes a report to help entities responsible for complying with Reliability Standard MOD-032 to resolve model issues and improve the cases. NERC's 2021 Case Quality Metrics Assessment indicates that planners are not able to develop accurate system models (

e.g.,

all interconnections demonstrate either a consistent performance or worsening score in the unacceptable or not recommended model metrics).

See

NERC,

Case Quality Metrics Annual Interconnection-wide Model Assessment,

26-29 (Oct. 2021),

https://www.nerc.com/pa/RAPA/ModelAssessment/ModAssessments/2021_Case_Quality_Metrics_Assessment-FINAL.pdf.

47. Once Bulk-Power System planners and operators validate system models,

105

there must be additional requirements for generator owners, transmission owners, and distribution providers to communicate with Bulk-Power System planners and operators to ensure that any changes to IBR settings, configurations, and ratings are updated. Otherwise, the transmission system models will not adequately represent the behavior of the actual installed equipment.

106

While Reliability Standards MOD-032-1 and MOD-033-2 include iterative updating and validation processes, Reliability Standard MOD-032-1 does not require IBR-specific modeling data and parameters, and Reliability Standard MOD-033-2 does not contemplate the technology-specific performance characteristics of registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate.

105

This final action uses “validation” to mean the confirmation that a model reflects real world operational behaviors and uses “verification” to mean a model is properly parameterized and validated.

106

See

NOPR, 181 FERC ¶ 61,125 at P 39 n.91.

48. Once Bulk-Power System planners and operators have validated system models, Bulk-Power System planners and operators need to coordinate with generator owners, transmission owners, and distribution providers so that the system models adequately represent all generation resources—including registered IBRs, unregistered IBRs, IBR-DERs in the aggregate, and synchronous generation—as well as load. Reliability Standards MOD-032-1 and MOD-033-2 do not require the applicable entities to work collaboratively to create interconnection-wide models that

accurately reflect the real-world interconnection-wide performance and behavior of registered and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate.

107

As a result, the models developed and deployed in compliance with these standards do not contemplate that IBRs can reduce power, trip offline, or enter momentary cessation individually or in the aggregate in response to a single fault on a transmission or sub-transmission system.

107

Reliability Standard MOD-032-1 is applicable to the following registered entities: (1) balancing authorities, (2) generator owners, (3) planning authorities/planning coordinators, (4) load serving entity, (5) resource planners, (6) transmission owners, (7) transmission planners, and (8) transmission service providers. NERC has deregistered the load serving entity function and has an ongoing standard drafting team project to replace this function as an applicable entity in the Reliability Standards with the distribution provider function.

See

Project-2022-02 Modifications to TPL-001 and MOD-032.

3. Planning and Operational Studies

49. Once Bulk-Power System planners and operators have validated registered IBR, unregistered IBR, and IBR-DER aggregate modeling and operational data, the Reliability Standards must require that Bulk-Power System planning and operational studies account for the actual behavior of both registered IBRs and unregistered IBRs individually and in the aggregate, as well as IBR-DERs in the aggregate. The Reliability Standards do not require Bulk-Power System planning and operational studies to assess the performance and behavior of both registered and unregistered IBRs individually and in the aggregate (

e.g.,

IBRs tripping or entering momentary cessation individually or in the aggregate), as well as IBR-DERs in the aggregate. Reliability Standard TPL-001-5.1 (Transmission System Planning Performance Requirements) requires planning coordinators and transmission planners to plan to ensure reliable operations over a broad spectrum of system conditions and following a wide range of probable contingencies, but it does not require planning coordinators and transmission planners to assess the performance and behavior of registered and unregistered IBRs individually and in the aggregate, or IBR-DERs in the aggregate, during normal and contingency conditions for the reliable operation of the Bulk-Power System.

108

NERC has stated that the currently effective Reliability Standards do not mitigate the IBR reliability risks because the IBR issues are not properly detected by models and studies.

109

NERC has also found that there is an immediate need to enhance the currently effective Reliability Standards. NERC explains that there is a need to understand the extent of inverter performance risks and modeling deficiencies as well as to gather necessary data for the currently installed fleet.

110

108

Reliability Standard TPL-001-5.1 (Transmission System Planning Performance Requirements) was approved by the Commission and became effective on July 1, 2023.

See N. Am. Elec. Reliability Corp.,

Docket No. RD20-8-000 (June 10, 2020) (delegated letter order) (approving a NERC-proposed erratum to Reliability Standard TPL-001-5);

Transmission Plan. Reliability Standard TPL-001-5,

Order No. 867, 170 FERC ¶ 61,030 (2020) (approving Reliability Standard TPL-001-5).

109

See

Odessa 2021 Disturbance Report at 43 (explaining that “[p]lants are abnormally responding to [Bulk-Power System] disturbance events and ultimately tripping themselves off-line. These issues are not being properly detected by the models and studies conducted during the generator interconnection study process nor during annual planning assessments.”).

110

Odessa 2022 Disturbance Report at vii-ix.

4. Performance Requirements

50. The currently effective Reliability Standards do not account for the differences in response of registered IBRs and synchronous generation resources during normal and contingency conditions. The frequency of an interconnection depends on the instantaneous balance between load and generation resources, to which all resources contribute during both normal and contingency conditions. For frequency to be maintained, generation resources must remain connected to the grid and continue to support grid frequency (

i.e.,

ride through) during either loss of generation (underfrequency) or loss of load (overfrequency) related frequency deviations. Reliability Standard PRC-024-3 does not require registered IBRs (or any generator) to remain connected to the Bulk-Power System and to continue to inject current and support frequency inside the “no trip zone.”

111

Therefore, IBRs could continue to act adversely in response to normally cleared faults by continuing to exhibit momentary cessation and power reduction behaviors.

111

Reliability Standard PRC-024-3 is a voltage and frequency protection settings standard that specifies that a generating resource may neither trip nor enter momentary cessation (

i.e.,

cease injecting current) inside the boundaries of the frequency and voltage excursion curves. The area inside the boundaries of the frequency and voltage excursion curves is known as the “no-trip zone.”

see also

Odessa Disturbance White Paper at 5 (explaining there are standard features for modern inverters that should be enabled within IBR plants to better understand their response to grid events and improve overall fleet performance).

167

See supra

note 88.

86. As a general matter, we agree with ACP/SEIA regarding the need to balance the burden to generator owners of collecting and providing data collected by disturbance monitoring equipment with the benefit of that data to reliability. Thus, in developing the directed data collection requirements, we direct NERC to consider the burdens of generators collecting and providing data, while assuring that Bulk-Power System operators and planners have the data they need for accurate disturbance monitoring and analysis.

168

Likewise, regarding CAISO's request that the Commission direct NERC to consider requiring registered IBRs to provide additional data, we agree that such data collections may be warranted, and direct NERC to consider through its standards development process whether additional IBR data points (

e.g.,

telemetry collections or other automated platform integrations) are needed to further enhance real-time visibility of Bulk-Power System operations.

168

See

Order No. 693, 118 FERC ¶ 61,218 at P 188 (in directing NERC to address or consider NOPR comments, the Commission explained that it “does not direct any outcome other than that the comments receive consideration”).

3. Unregistered IBR and IBR-DER Data Sharing

87. In the NOPR, the Commission preliminarily found that the currently effective Reliability Standards do not ensure that Bulk-Power System planners and operators receive modeling data and parameters regarding unregistered IBRs that, individually or in the aggregate, are capable of adversely affecting the reliable operation of the Bulk-Power System. The Commission also preliminarily found that the currently effective Reliability Standards do not require that Bulk-Power System planners and operators receive modeling data and parameters regarding IBR-DERs that in the aggregate are capable of adversely affecting the reliable operation of the Bulk-Power System. The Commission preliminarily determined that planning coordinators and other entities need modeling data and parameters for both unregistered IBRs and IBR-DERs in the aggregate to assure greater accuracy in modeling.

169

NOPR, 181 FERC ¶ 61,125 at P 79.

88. The Commission proposed to direct NERC to submit new or modified Reliability Standards addressing IBR data sharing that require transmission owners to provide modeling data and parameters (

e.g.,

steady-state, dynamic, and short circuit modeling information, and control settings for momentary cessation and ramp rates) to appropriate registered entities (

e.g.,

planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities) for unregistered IBRs in their transmission owner areas where unregistered IBRs individually or in the aggregate materially affect the reliable operation of the Bulk-Power System.

170

The Commission similarly proposed to direct NERC to develop new or modified IBR data sharing Reliability Standards that require distribution providers to provide modeling data and parameters to appropriate registered entities (

e.g.,

planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities) for IBR-DERs in the aggregate connected in their distribution provider areas where those IBR-DERs in the aggregate materially affect the reliability of the Bulk-Power System and are not otherwise subject to compliance with Reliability Standards.

171

170

Id.

171

Id.

(citing NERC,

Reliability Guideline: Parameterization of the DER_A Model,

8-16 (Sept. 2019),

https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Reliability_Guideline_DER_A_Parameterization.pdf

(2019 DER_A Model Guideline) (retired)).

89. The Commission stated that this approach would be similar to that taken in other Reliability Standards that require transmission owners and distribution providers to provide certain planning and operational data received from unregistered entities to appropriate registered entities (

e.g.,

planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities).

172

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

173

The Commission instead proposed that the new or modified Reliability Standards should permit distribution providers to provide modeling data and parameters of IBR-DERs in the aggregate or equivalent for IBR-DERs interconnected to their distribution systems (

e.g.,

i.e.,

planning coordinators, transmission planners, reliability coordinators, transmission operators, and balancing authorities).

174

172

Id.

P 80 (noting that this approach is consistent with certain currently effective Reliability Standards and citing Reliability Standard IRO-010-2 (Reliability Coordinator Data Specification and Collection), Requirement R1 (providing that “[t]he Reliability Coordinator shall maintain a documented specification for the data . . .

including non-[bulk electric system] data

”(emphasis added)), Requirement R2 (providing that “[t]he Reliability Coordinator shall distribute its data specification to entities”), Requirement R3 (providing that “[e]ach . . . Transmission Owner, and Distribution Provider receiving a data specification in Requirement R2 shall satisfy the obligations of the documented specifications”); Reliability Standard PRC-006-3 (Automatic Underfrequency Load Shedding), Requirement R8 (requiring that a UFLS entity,

i.e.,

relevant transmission owner and distribution provider, “provide data to its Planning Coordinator(s)”)). Reliability Standard IRO-010-4 (Reliability Coordinator Data Specification and Collection) became effective April 1, 2023; Reliability Standard PRC-006-5 (Automatic Underfrequency Load Shedding) became effective April 1, 2021.

173

Id.

174

Id.

(citing NERC,

Distributed Energy Resources: Connection Modeling and Reliability

Considerations,

7 (Feb. 2017),

https://www.nerc.com/comm/Other/essntlrlbltysrvcstskfrcDL/Distributed_Energy_Resources_Report.pdf

(NERC DER Report); 2019 DER_A Model Guideline).

a. Comments

90. Commenters generally support the NOPR's proposed directive to require transmission owners to collect and share unregistered IBR data and to require distribution providers to collect and share modeling data and parameters of IBR-DERs in the aggregate.

175

However, several commenters raise concerns that transmission owners and distribution providers may not be able to collect all the requested data.

176

175

See generally

NERC Initial Comments at 9; AEU Initial Comments at 5; ACP/SEIA Initial Comments at 11-12 (although cautioning against mandating specific modeling and data submissions to allow entities to identify and request the data and modeling that best meets their needs); IRC Initial Comments at 2-3; ISO-NE Initial Comments at 2; NYSRC Initial Comments at 2; Ohio FEA Initial Comments at 2, 9.

176

See

AEP Initial Comments at 4; APS Initial Comments at 4; Trade Associations Initial Comments at 11-12; and SCE/PG&E Initial Comments at 10-11.

91. NERC, AEU, IRC, and ISO-NE support the Commission's directive to revise the currently effective Reliability Standards to require that adequate and accurate data is available for all Bulk-Power System-connected resources (including unregistered IBRs).

177

NERC notes that experience has demonstrated that, without all of the relevant protections and controls being modeled and validated, the resulting interconnection and long-term planning studies will not identify possible performance issues.

178

NERC recommends that if no distribution provider is registered on a specific system, the transmission owner should coordinate with the relevant transmission planner, planning coordinator, balancing authority, transmission operator, and/or reliability coordinator for developing, submitting, and validating aggregate DER models (inclusive of IBR-DER) in planning or operational studies.

179

177

NERC Initial Comments at 9; AEU Initial Comments at 4, 7; IRC Initial Comments at 2; ISO-NE Initial Comments at 2.

178

NERC Initial Comments at 13.

179

Id.

92. IRC also supports Reliability Standards that facilitate the provision of IBR-related data from registered entities to reliability coordinators, planning coordinators, and other registered entities responsible for the safe and reliable operation of the Bulk-Power System.

180

To ensure the appropriate data is provided, IRC requests that the final rule specify the data to be submitted by all types of IBRs (

i.e.,

registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate) and transmission devices using similar technologies.

181

180

IRC Initial Comments at 2.

181

Id.

at 3.

93. ISO-NE supports the Commission's proposed directive and asserts that, for smaller IBR-DERs, distribution providers are in the best position to provide aggregate models that include behind-the-meter resources.

182

ISO-NE notes that, in the absence of this aggregate data, it uses assumptions based on industry documents and benchmarking to actual events, which may not always reflect the realities of IBRs.

183

Ohio FEA supports the Commission's proposals and states that the lack of visibility into operating assets behind the meter, including ride through of IBR-DERs, is an ongoing issue.

184

182

ISO-NE Reply Comments at 2, 5.

183

ISO-NE Initial Comments at 2.

184

Ohio FEA Initial Comments at 2, 9.

94. AEU states that distribution providers are best situated to fulfill Reliability Standard requirements related to the aggregate impact of IBR-DERs and cautions against any direct assignment of responsibility to owners or operators of individual IBR-DERs.

185

AEU Initial Comments at 7.

95. CAISO, Indicated Trade Associations, and SPP generally support the proposed directive but caution that transmission owners and distribution providers should only be required to collect and share information that they can reasonably obtain, and that certain data may be difficult to obtain.

186

CAISO encourages the Commission to direct NERC to address the potential “compliance trap” and suggests that if the Commission is going to shift the compliance burden to transmission owners and distribution providers from the IBR generator owner or operator, there should be consistent mechanisms in place for transmission owners and distribution providers to receive such information.

187

186

CAISO Initial Comments at 31; Indicated Trade Associations Initial Comments at 9; SPP Initial Comments at 2.

187

CAISO Initial Comments at 32, 38.

96. APS, AEP, LADWP, and SCE/PG&E raise concerns with the proposed directive requiring transmission owners to collect and share unregistered IBR data and distribution providers to collect and share IBR-DER data due to the lack of mechanisms or leverage in place to require the provision of the underlying data from unregistered entities.

188

For example, AEP explains that it does not have access, as a transmission owner, to all of the data necessary to model the behavior of unregistered IBRs, nor does it have access, as a distribution provider, to all the data needed to accurately model IBR-DERs in the aggregate.

189

188

APS Initial Comments at 4; AEP Initial Comments at 2; LADWP Reply Comments at 2; SCE/PG&E Initial Comments at 6.

189

AEP Initial Comments at 4.

97. SCE/PG&E contend that it is inappropriate for NERC to develop new Reliability Standards that place a compliance burden on transmission owners and distribution providers for unregistered IBRs and IBR-DERs in the aggregate. SCE/PG&E explain that transmission owners and distribution providers would not have the requisite information to comply with the Reliability Standards and that the transmission owners and distribution providers would need to develop new procedures and provide oversight and enforcement for unregistered IBRs and IBR-DERs. SCE/PG&E further state that balancing authorities, rather than transmission owners and/or distribution providers, should be held responsible for oversight and enforcement as they have the greatest visibility into the operation of IBRs on the grid.

190

SCE/PG&E Initial Comments at 6-7.

98. APS suggests alternatives to the proposed IBR-DER directive. APS has concerns with the proposal to require distribution providers to share information provided by an unregistered entity because the IBR-DER customer may be unable or unwilling to provide the data voluntarily.

191

Therefore, APS recommends that the Commission not direct NERC to require distribution providers to collect and share IBR-DER data, but instead defer to the stakeholder process during the standards development process to determine who will provide the data, how the aggregate IBR-DER model will be developed, and how the model will be validated.

192

191

APS Initial Comments at 4.

192

Id.

at 4.

99. APS and Indicated Trade Associations oppose a directive requiring transmission owners and distribution providers to collect and share data from unregistered IBRs and IBR-DERs in the aggregate. Indicated Trade Associations emphasize that, while it may be appropriate to specify the types of data to be submitted, a registered entity cannot provide data that the registered entity itself does not have and has no ability to collect.

193

APS believes that the unregistered IBRs and IBR-DERs may be unable or unwilling to provide the data voluntarily and consistently, and that transmission owners will have little to no leverage to compel delivery of data from the unregistered entities; thus, these requirements are more effectively shouldered by the IBR owners.

194

Indicated Trade Associations explain that, in most if not all cases, a transmission owner or distribution provider has only the information provided to it during the interconnection approval process and interconnection agreements may not require the IBRs to provide modeling data. Indicated Trade Associations explain that in such a case, transmission owners and distribution providers may not have the contractual right to add requirements to provide data unilaterally and retroactively. In addition, Indicated Trade Associations clarify that some IBR-DERs on the distribution system interconnect under utility retail tariffs without a separate interconnection agreement. Indicated Trade Associations aver that transmission owners and distribution providers should not be held responsible for an unregistered IBR owner that does not or cannot provide the data, and that any directives regarding unregistered IBR and IBR-DER data sharing and model validation should recognize this limitation.

195

193

Indicated Trade Associations Initial Comments at 10.

194

APS Initial Comments at 4.

195

Indicated Trade Associations Initial Comments at 10-13.

100. Alternatively, Indicated Trade Associations propose that the Commission could either convene a forum to consider the benefits of applying the new Reliability Standards to distribution providers with IBR-DERs in their footprints, or direct NERC to submit a study on the challenges for development and implementation of those new or modified Reliability Standards. Indicated Trade Associations also support NERC's request for flexibility in determining appropriate requirements with respect to collecting and modeling IBR-DER data. In the alternative, Indicated Trade Associations ask the Commission to limit the obligations shouldered by the distribution providers to what is feasible.

196

Id.

at 9, 12-13.

101. Indicated Trade Associations recommend giving consideration to collecting data from existing registered generator owners and operators that also own some IBR-DERs.

197

Id.

at 2.

b. Commission Determination

102. Pursuant to section 215(d)(5) of the FPA, we adopt the NOPR proposal, with modification. Specifically, as proposed in the NOPR, we direct NERC to submit to the Commission for approval one or more new or modified Reliability Standards that require: (1) transmission owners to provide to Bulk-Power System planners and operators modeling data and parameters for unregistered IBRs in their transmission owner areas that, individually or in the aggregate, materially affect the reliable operation of the Bulk-Power System and (2) distribution providers to provide to Bulk-Power System planners and operators modeling data and parameters for IBR-DERs in the aggregate in their distribution provider areas where the IBR-DERs in the aggregate materially affect the reliable operation of the Bulk-Power System.

198

See supra

note 14 (noting that although the remaining subset of unregistered IBRs and IBR-DERs in the aggregate will not be subject to the mandatory and enforceable Reliability Standards set forth herein, they may be subject to provision of data and information to their respective transmission owners and distribution providers, as applicable, in accordance with their specific interconnection agreements; and encouraging NERC to continue its efforts to review and evaluate whether reliability gaps continue to remain and if new or modified functional registration categories or Reliability Standards are necessary).

103. However, we find persuasive the comments explaining that certain data may be challenging or infeasible for the transmission owner or distribution provider to obtain.

199

We recognize that there may be limitations on the ability of certain transmission owners to provide all data about unregistered IBRs that Bulk-Power System transmission planners and operators may need for the reliable operation of the Bulk-Power System. Likewise, there may be limitations on the ability of certain distribution providers to provide all data about IBR-DERs in the aggregate that Bulk-Power System transmission planners and operators may need for the reliable operation of the Bulk-Power System. We therefore modify the NOPR proposal, as discussed below.

199

See, e.g.,

AEP Initial Comments at 2; APS Initial Comments at 4; Indicated Trade Associations Initial Comments at 10; SCE/PG&E Initial Comments at 6, 7.

104. Recognizing that there may be instances in which transmission owners are unable to gather adequate unregistered IBR modeling data and parameters to create and maintain unregistered IBR models in their transmission owner areas, we modify the NOPR proposal and direct NERC to develop new or modified Reliability Standards that require each transmission owner, if unable to gather accurate unregistered IBR data or unable to gather unregistered IBR data at all, to provide instead to the Bulk-Power System planners and operators in their areas: (1) an estimate of the unregistered IBR modeling data and parameters, (2) an explanation of the limitations of the availability of data, (3) an explanation of the limitations of any data provided by unregistered IBRs, and (4) the method used for estimation. We believe that this directive appropriately balances commenters' concerns about data accessibility and burden with the established need for transmission owners to provide unregistered IBR modeling data and parameters to Bulk-Power System planners and operators in their transmission owner area. We recognize that estimated modeling data and parameters are approximations of actual modeling data and parameters. We further acknowledge that there is some degree of error in estimated modeling data and parameters. However, on balance we believe that requiring such estimates with explanation of any limitations is an improvement from not having any data at all; and that even estimates will increase the overall adequacy of models and improve the reliability of the Bulk-Power System. To support this data collection, we further direct NERC to consider commenters suggestions to implement a process or mechanism by which transmission owners would receive modeling data and parameters.

200

See, e.g.,

AEP Initial Comments at 2; SCE/PG&E Initial Comments at 6-7.

105. We also recognize that there may be instances where distribution providers are similarly unable to gather adequate modeling data and parameters from IBR-DERs.

201

Accordingly, to account for instances in which distribution providers are unable to gather adequate modeling data and parameters of IBR-DERs to create and maintain IBR-DER models, we modify the NOPR proposal and direct NERC to develop new or modified Reliability Standards that require that each distribution provider, if unable to gather accurate IBR-DERs data in the aggregate or unable to gather IBR-DERs data in the aggregate at all, provide instead to

the Bulk-Power System planners and operators in their areas: (1) an estimate of the modeling data and parameters of IBR-DERs in the aggregate,

202

(2) an explanation of the limitations of the availability of data, (3) an explanation of the limitations of the data provided by IBR-DERs, and (4) the method used for estimation. In support of above, we further direct NERC to consider commenters' suggestions to implement a process or mechanism by which distribution providers would receive modeling data and parameters.

203

201

For example, there may be no distribution providers that meet the NERC Registration Criteria in a given area (

e.g.,

greater than 75 MW of peak load directly connected to the bulk-electric system, facilities that are used in protection systems or programs for the protection of the bulk-electric system, etc.),

see

NERC Rules of Procedure App. 5B (Statement of Compliance Registry Criteria) 6-7, (Jan. 19, 2021),

https://www.nerc.com/FilingsOrders/us/RuleOfProcedureDL/Appendix%205B.pdf.

202

See supra

note 89.

203

See infra

P 147 (identifying the EPRI DER Settings Database as one potential technical source for IBR-DER estimation data).

106. Finally, as noted by commenters, we recognize that there may be instances where IBR-DERs are connected to an entity that does not meet the criteria for registration with NERC as a distribution provider. For those areas with IBR-DERs that in the aggregate materially affect the reliable operation of the Bulk-Power System but do not have an associated registered distribution provider, we direct NERC to determine the appropriate registered entity responsible for providing data of IBR-DERs that in the aggregate have a material impact on the Bulk-Power System, or, when unable to gather such accurate IBR-DERs data, to provide instead to the Bulk-Power System planners and operators in their areas: (1) an estimate of the modeling data and parameters of IBR-DERs that in the aggregate have a material impact on the Bulk-Power System, (2) an explanation of the limitations of the availability of data, (3) an explanation of the limitations of any data provided by the IBR-DERs that in the aggregate have a material impact on the Bulk-Power System, and (4) the method used for estimation.

107. We believe that requiring transmission owners and distribution providers to collect required data for unregistered IBRs, and IBR-DERs in the aggregate, will result in greater consistency than the piecemeal approach proposed by Indicated Trade Associations, in which some data for unregistered IBRs and IBR-DERs in the aggregate would also be provided by registered generator owners and operators. Further, we believe that transmission owners and distribution providers are in a better position to collect and estimate required data for unregistered IBRs and IBR-DERs in the aggregate that are directly connected to their respective areas than balancing authorities. We anticipate that the need for estimated data for unregistered IBRs connected to the Bulk-Power System, as opposed to actual data, and thus the burden of collecting such data, will decrease over time due to the model provision requirements in the

pro forma

LGIP and

pro forma

SGIP, as adopted in Order No. 2023,

204

and the ongoing NERC activities to register IBR generator owners and operators.

205

As transmission providers modify their interconnection agreements in compliance with Order No. 2023, we expect that the need to estimate data will decrease because validated models for smaller sized resources will begin to be submitted to transmission providers with interconnection requests under the Commission's

pro forma

SGIP. NERC's registration of previously unregistered IBRs should result in more IBRs providing data and validated models pursuant to applicable Reliability Standards.

206

204

Order No. 2023, 184 FERC ¶ 61,054 at P 1659 (revising Attachment A to Appendix 1 of the

pro forma

LGIP and Attachment 2 of the

pro forma

SGIP to require each interconnection customer requesting to interconnect a non-synchronous generating facility to submit to the transmission provider specified modeling information).

205

See

Order Approving Workplan, 183 FERC ¶ 61,116 at P 1 (approving NERC's plan to modify its Rules of Procedure related to registration and to identify and register IBR generator owners and operators that fall below the thresholds for the bulk-electric system definition). NERC's Commission approved bulk electric system definition is a subset of the Bulk-Power System and defines the scope of the Reliability Standards and the entities subject to NERC compliance.

Revisions to Electric Reliability Org. Definition of Bulk Elec. Sys. & Rules of Proc.,

Order No. 773, 141 FERC ¶ 61,236 (2012),

order on reh'g,

Order No. 773-A, (May 17, 2013), 143 FERC ¶ 61,053 (2013),

rev'd sub nom. People of the State of N.Y.

FERC,

783 F.3d 946 (2d Cir. 2015); NERC Glossary at 7-9.

206

NERC's August 16, 2023, Compliance Filing sets forth NERC's proposed registration plan indicating that implementation of the plan will result in registration of 97.5 percent of Bulk-Power System connected IBRs of the total IBR nameplate capacity MWs installed in 2021 of transmission and sub-transmission IBRs.

108. Regarding CAISO's concern regarding the potential “compliance trap” where planners and operators rely on third-party data

207

and IRC's request that the final rule specify the data to be submitted by all IBRs (

i.e.,

registered IBRs, unregistered IBRs, and IBR-DERs in the aggregate) and transmission devices using similar technologies, we direct NERC to determine through its standards development process the minimum categories or types of data that must be provided to transmission planners, transmission operators, transmission owners, and distribution providers necessary to predict the behavior of all IBRs and to ensure that compliance obligations are clear.

208

As discussed in more detail in section IV.C of this final action, we are also directing NERC to develop new or modified Reliability Standards that require the use of approved industry IBR models that accurately reflect the behavior of all IBRs during steady state, short-circuit, and dynamic conditions. By contrast, we believe that a directive to task distribution providers as the appropriate registered entity to collect and share the modeling data and parameters of IBR-DERs in the aggregate is preferable to deferring to the stakeholder process as suggested by APS. The distribution provider, as the entity providing and operating the lines between the transmission and distribution systems,

209

is the entity best situated to have access to the data necessary for accurate estimation and, other than Indicated Trade Associations that suggested the piecemeal approach already discussed above, no commenter identified other potential entities as an equally efficient option.

207

CAISO Initial Comments at 38.

208

See

Order No. 672, 114 FERC ¶ 61,104 at PP 322, 325 (requiring that Reliability Standards be clear and unambiguous as to what is required and who is required to comply).

209

See

NERC Rules of Procedure, App. 5B at 6.

109. We also decline to either convene a forum to consider the benefits of applying the new Reliability Standards to distribution providers with IBR-DERs in their footprints, or direct NERC to submit a study on the challenges for development and implementation of those new or modified Reliability Standards as suggested by Indicated Trade Associations. As identified in the NOPR and expounded upon in this final action, there is a pressing need to address the gap posed by the currently effective Reliability Standards. Bulk-Power System planners and operators need to receive modeling data and parameters regarding IBR-DERs that in the aggregate are capable of adversely affecting the reliable operation of the Bulk-Power System. The additional process proposed by commenters will unnecessarily delay resolution of the identified gap. Further, regarding various comments suggesting specific timing for requiring data provision, we believe that determining when data would be available and required to be provided is better addressed during the standards development process. We encourage NERC to continue its efforts to review and evaluate whether reliability gaps continue to remain and if new or modified functional registration categories or Reliability Standards are necessary to ensure the reliable operation of the Bulk-Power System. NERC may choose to revise, or the Commission may direct further

revisions to, registration or Reliability Standards to ensure the provision of adequate modeling data and parameters from unregistered IBRs and/or IBR-DERs in the aggregate.

C. Data and Model Validation

110. In the NOPR, the Commission preliminarily found that the currently effective Reliability Standards are inadequate to ensure that Bulk-Power System planners and operators: (1) have the steady state, dynamic, and short circuit models of the elements that make up generation, transmission, and distribution facilities that accurately reflect the generation resource's behavior in steady state and dynamic conditions; (2) have dynamic models (

i.e.,

models of equipment that reflect the equipment's behavior during various grid conditions and disturbances) that accurately represent the dynamic performance of all generation resources, including momentary cessation when applicable; (3) can validate and update resource models by comparing the provided data and resulting models against actual operational behavior to achieve and maintain accuracy of their transmission planning and operations models; and (4) have interconnection-wide models that represent all generation resources, including: (a) synchronous generation resource models; (b) load resource models; and (c) registered and unregistered IBR models, as well as IBR-DERs modeled in the aggregate. The Commission further stated that Bulk-Power System planners and operators need accurate planning, operations, and interconnection-wide models to ensure reliable operation of the system.

210

NOPR, 181 FERC ¶ 61,125 at P 82.

111. Therefore, the Commission proposed to direct NERC to submit to the Commission for approval one or more new or modified Reliability Standards that would ensure that all necessary models are validated. Specifically, the Commission proposed to direct NERC to modify the Reliability Standards to require: (1) generator owners to provide validated registered IBR models to the planning coordinators for interconnection-wide, planning, and operations models; (2) transmission owners to provide validated unregistered IBR models to the planning coordinators for interconnection-wide, planning, and operations models; and (3) distribution providers to provide validated models of IBR-DERs in the aggregate to the planning coordinators for interconnection-wide, planning, and operations models. Further, the Commission proposed that the new or modified Reliability Standards should require models of individual registered and unregistered IBRs, as well as IBR-DERs in the aggregate, to represent the dynamic behavior of these IBRs at a sufficient level of fidelity for Bulk-Power System planners and operators to perform valid facility interconnection, planning, and operational studies on a basis comparable to synchronous generation resources.

211

Id.

P 83.

1. Approved Component Models

112. In the NOPR, the Commission preliminarily found that without approved generation models that accurately reflect generation resource behavior in steady state and dynamic conditions, Bulk-Power System planners and operators are unable to adequately predict IBR behavior and their subsequent impact on the Bulk-Power System.

212

The Commission found that the currently effective Reliability Standards only refer broadly to models in Reliability Standard MOD-032-1, Attachment 1, rather than requiring the use of NERC's approved component models, which would provide more accurate information about resource behavior. Thus, the Commission proposed to direct NERC to develop new or modified Reliability Standards that require the use of approved industry generic library IBR models that accurately reflect the behavior of IBRs during both steady state and dynamic conditions.

212

Id.

P 86 (citing NERC Standardized Powerflow Parameters and Dynamics Models).

113. The Commission elaborated that NERC could reference its approved component model list in the Reliability Standards and require that only those models be used when developing planning, operations, and interconnection-wide models. The Commission further stated that the proposed directives were consistent with the recommendations in the NERC reports.

213

Id.

a. Comments

114. AEP, CAISO, ISO-NE, LADWP, and NYSRC generally support the proposed directive to require the use of approved industry generic library IBR models

214

(

e.g.,

NERC's approved model list) instead of user-defined models.

215

As an owner of registered IBRs, unregistered IBRs, and IBR-DERs, AEP confirms that transmission owners and distribution providers need consistent and accurate data to properly model IBR be

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