At the end of 2023, U.S. interconnection queues contained twice as much capacity as is currently installed in the country, and more than 95% of this generation is inverter-based resources (IBRs). (See the ESIG blog on August 5, 2024, “A DOE Roadmap to Unlock Interconnection Queue Backlogs,” by Will Gorman from Lawrence Berkeley National Laboratory (LBNL) for more information on the interconnection queue.) However, the challenges and opportunities brought by IBRs in terms of grid reliability are very different from those of conventional fossil-fueled and hydro generation.
To reliably and securely operate wind, solar, and battery storage resources connected to the bulk power system requires comprehensive interconnection and reliability standards for IBRs. The standards need to address such issues as IBR capabilities, expected performance, and cybersecurity requirements. Ideally, the standards should be harmonized across the U.S., and even globally, to help to ensure efficiency and lower costs for equipment manufacturing and IBR integration.
In the U.S. there are a number of ongoing efforts to develop, adopt, and potentially harmonize reliability standards for IBRs, briefly described below.
IEEE 2800-2022
IEEE 2800-2022 Standard for Interconnection and Interoperability of Inverter-Based Resources Interconnecting with Associate Transmission Electric Power Systems was developed in 2022 by a large body of industry experts from utilities, system operators, transmission planners, and manufacturers following an open and consensus-based process. It provides a harmonized set of technical minimum interconnection capability and performance requirements that “raise the bar” to make power systems with high shares of IBRs more reliable, yet leaves sufficient space for specific regions or entities to establish requirements beyond those in the standard, if needed. More details about IEEE 2800-2022 can be found in the materials for the online Joint Generator Interconnection Workshop.
However, IEEE 2800-2022 is not enforceable until it is adopted and implemented by entity responsible for administering the interconnection process and requirements—either a regulatory body, an independent system operator or regional transmission organization (ISO/RTO), or a transmission provider. Recognizing the comprehensiveness of this standard and its ability to address systemic issues observed in NERC disturbance events, some ISO/RTOs and transmission providers in the U.S. have already started on the path of using IEEE 2800-2022. Four adoption strategies are currently being undertaken by different ISOs and utilities, each with certain advantages and disadvantages (see the figure below).
IEEE 2800-2022 Adoption Strategies
General reference: This adoption strategy references IEEE 2800-2022 in its entirety in the entity’s existing binding documents or codes. The main challenge with this approach is that the standard explicitly requires the adopting entity to make a number of important decisions and specify, for example, the reference point of applicability, chose specific settings from provided ranges and chose certain performance metrics. Without such specifications, the adoption is incomplete and uncertain.
Detailed reference with or without customization: This adoption strategy cites specific clauses of IEEE 2800-2022, allowing for a targeted or phased approach. While this approach could, and ideally should, include specifications of functional settings that customize IBR performance, this is not always the case. The absence of customization for functional settings may in turn lead to lack of clarity in case of conflicts between IEEE 2800-2022 and existing interconnection requirements.
Hybrid integration with reference, customization, and additional specifications: This strategy builds on the detailed reference with customization approach and adds clarifying language, modifications, and even additional requirements as needed for local system needs. It strikes a balance between effectiveness and ease of adoption. The additional clarity and specifications of subclauses of IEEE 2800-2022 add necessary details for applicable entities to effectively implement the standard.
Full specification and customization: This strategy is similar to the hybrid approach but instead of referencing, it copy/pastes (sometimes with modifications) the IEEE 2800-2022 requirements into existing requirements documents or recreates the requirements language entirely. This approach is comprehensive but may require duplication of work and a permission from IEEE SA to use or modify their copyright-protected content.
IEEE 2800-2022 Adoption Strategies
Note: AGIR = Authority Governing Interconnection Requirements.
Source: Elevate Energy Consulting.
The adoption patterns we’re generally seeing are that entities that have not yet developed their own comprehensive interconnection requirements for bulk power system–connected IBRs have chosen IEEE 2800-2022 adoption by general reference, and entities that already have their own comprehensive interconnection requirements have chosen one of the other three adoption methods.
In 2022, work began on IEEE P2800.2, “Recommended Practice for Test and Verification Procedures for Inverter-based Resources Interconnecting with Bulk Power Systems,” to develop an accompanying set of uniform recommended practices regarding testing and verification of conformity with IEEE 2800-2022 requirements. IEEE P2800.2 focuses on plant-level conformity, which requires inverter-level tests and verification as well as overall IBR plant design evaluation, modeling, and studies; “as-built” evaluation; plant commissioning practices; and post-commissioning performance monitoring and validation throughout the lifecycle of an IBR plant. The widespread use of these practices could help support a more reliable and resilient IBR fleet in conformity with IEEE 2800-2022 requirements moving forward. IEEE P2800.2 is intended to be balloted and published in 2025.
FERC Order 901, NERC Work Plan and Standards Revisions
The adoption of IEEE 2800-2022 is voluntary, and, to date, too few entities have adopted it or are taking steps toward its adoption, effectively falling short of addressing persisting reliability risks. Therefore, regulatory entities are now stepping in more authoritatively to invoke changes to North American reliability standards applicable to IBRs. In October 2023, the Federal Energy Regulatory Commission (FERC) issued Order No. 901 that directed NERC to make sweeping changes to its reliability standards applied to IBRs and address significant gaps related to data sharing, model validation, performance requirements, and planning and operation studies. Additionally, FERC ordered NERC to modify its registration requirements to include smaller IBRs connected to the bulk power system that have a material impact on bulk power system reliability. In response, in January 2024, NERC published a workplan identifying priorities for standard improvement and the development of new standards (NERC, 2024). NERC also regularly publishes progress updates to FERC.
The first batch of new NERC standards is expected to be filed with FERC in November 2024:
- PRC-028 for IBR disturbance monitoring and reporting
- PRC-029 for IBR ride-through capability and performance requirements
- PRC-030 for IBR performance analysis and issue mitigation
The standards are being developed by NERC Standard Drafting Teams (SDT) made up of industry stakeholders. SDT meetings are open to the public, and all interested parties can participate in the drafting process.
U.S. DOE i2X Forum for the Implementation of Reliability Standards (FIRST)
To help industry navigate changing standards and the interconnection requirements landscape, the U.S. Department of Energy (DOE) established a Forum on the Implementation of Reliability Standards (FIRST). The forum is led by the DOE Solar and Wind Energy Technology Offices in partnership with LBNL, ESIG, and EPRI, with support from Elevate Energy Consulting. i2X FIRST is focusing on the cohesive implementation of solutions outlined in the i2X Roadmap (developed in 2023) related to standards, leveraging insights from early adopters.
The purpose of this forum is to go beyond the dissemination of standard language and to (1) delve into specific enhancements of interconnection requirements, (2) facilitate the practical implementation of IEEE 2800-2022, and (3) discuss linkages with regulatory activities such as FERC Order No. 901 and relevant NERC Standards that are under revision or in development. Interested parties can sign up for i2X FIRST meetings and access meeting materials, agendas and recordings on the project webpage.
Call to Action
ISO/RTOs, transmission providers, and their customers will benefit from adopting large parts of voluntary industry standards such as IEEE 2800-2022 as an effective solution to mitigate reliability risks during this energy transition. IEEE 2800-2022 is intended to help raise the bar in terms of forward-looking IBR capabilities and configurable performance requirements. Both IEEE 2800 and the NERC standards will evolve in the years to come; however, this should not hinder or preclude industry from seeking harmonized and consistent IBR capability and performance requirements for newly connecting IBRs to the extent possible.
The rapid pace of the energy transition calls for proactive steps to mitigate risks. The adoption of voluntary technical standards plays a major role in this process and can help inform policies, regulatory rulemaking, and other business decisions, as well as help streamline and expedite the interconnection process for new IBRs. Some degree of flexibility and latitude may be needed by the transmission provider and interconnection customer in applying requirements to existing and emerging technologies.
Julia Matevosyan
Associate Director, Chief Engineer
ESIG
Ryan Quint
Founder and CEO
Elevate Energy Consulting
Jens Boemer
Technical Executive
EPRI
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