Interconnection Grade Criteria
Table of Contents
The interconnection criteria included in Freeing the Grid (FTG) represent best practices and model provisions informed by stakeholder discussions and adopted through state regulatory proceedings.
The 2023 version of FTG includes 56 criteria worth 63 possible points that are separated into 10 categories. For comparison, the last release of FTG in 2017 included 42 criteria—including seven bonus criteria—worth 30 possible points.
Because of the substantial changes in the number of criteria, reflective of new best practices in energy storage interconnection and other provisions, the state grades for 2023 are not being compared to state grades in prior FTG releases.
New and Updated Criteria
To revise and incorporate additional FTG criteria, IREC identified key provisions included in its 2019 Model Interconnection Procedures (the 2019 version has since been updated with the 2023 Model Interconnection Procedures). IREC also referred to the solutions and model language developed as part of Building A Technically Reliable Interconnection Evolution for Storage (BATRIES), a project funded by the U.S. Department of Energy that identified and developed solutions to regulatory and technical barriers to the interconnection of energy storage and solar-plus-storage systems to the distribution grid. These solutions and model language were published in the resulting Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage.
The BATRIES project team1 also discussed new provisions that have been adopted by certain states and identified as emerging best practices, such as improved review processes (e.g., initial review screens) to decrease the time and cost of interconnection while continuing to maintain safety and reliability.
In addition to internal discussions to refine and update the criteria, IREC solicited feedback from third-party interconnection experts to ensure that the final criteria represent the most critical provisions and practices for streamlined project review and connection to the grid.2
A list of all criteria by category and a brief discussion of each is below (new criteria and language are indicated in red text and the tables also include the number of states or territories that received full or partial credit for each criterion).
Rule Applicability Category
The Rule Applicability category measures whether a state’s interconnection procedures provide clarity on the types and sizes of generators that are allowed to connect under the procedures. These provisions can become especially important for applicants seeking to interconnect a system that may not be explicitly mentioned in the rules, such as an energy storage system or a project that exceeds the stated size threshold but still falls under the jurisdiction of the state. Incorporating new technologies, such as energy storage, and specifying that all state-jurisdictional interconnections are covered under the rules helps to increase process transparency and clarity.
Best Practices
- Explicitly include energy storage systems as an eligible technology in the rules (e.g., within the definition of “generating facility,” “distributed energy resource,” or similar term)
- Remove any size limit restriction to allow all state-jurisdictional interconnections to be eligible under the rules
Streamlined Review Category
The criteria under the Streamlined Review category relate to how projects are reviewed for grid impacts and whether the interconnection procedures require faster processing times for systems that meet system size or other eligibility requirements. With the exception of the last criterion above, these provisions can speed up the interconnection process for projects by altering the type of review based on location (e.g., group studies) or system size (e.g., simplified and expedited processes), while continuing to maintain safety and reliability.
Note on Simplified and Expedited Review
Under simplified3 and expedited4 review, technical evaluation (i.e., evaluation to ensure that the project would not cause adverse grid impacts) is typically limited to a set of screens or thresholds that identify systems that could trigger adverse system impacts and require closer review. Increasing the size limits for simplified and expedited review can allow more projects to go through these more efficient screening processes and potentially avoid longer study processes.
For projects that can be programmed to operate below their rated—or nameplate—capacity, such as energy storage systems paired with a device that can limit the amount of power sent to the grid, basing review process eligibility on that export capacity would allow projects that operationally fall under the size limits to go through streamlined review.
Note on Group Studies
Another way to potentially streamline review is through group studies. Some states have begun to implement group or cluster study processes as a way to review a set of projects at the same time (as opposed to the current approach which reviews projects sequentially) and to allow interconnection customers to more fairly share the costs of upgrading equipment on the grid when constraints are identified.
Note on Equitable Interconnection
Interconnection policy discussions traditionally have not included consideration of how interconnection can pose a barrier to equitable access to sustainable energy for disinvested,5 BIPOC, and low-wealth communities, which often suffer from significant underinvestment in grid infrastructure. To address equitable access to the grid, interconnection policies and practices can be designed to reduce barriers, and increase access, to clean energy in disadvantaged or underserved communities. IREC added this provision to signal that this is an important and emerging area of interconnection policy. New Mexico is the only state that received credit for this criterion through a provision that includes increasing access to low-income subscribers and underserved communities as a metric for determining whether there is a public benefit to employing a cost-sharing mechanism.6
Best Practices
- Offer simplified and expedited review processes for inverter-based systems that base system size eligibility on export capacity
- Adopt a group or cluster study review option
- Incorporate a provision that helps to support DER interconnections that benefit disinvested, BIPOC, and low-wealth households and communities
Modifications Category
The criteria under the Modifications category measure whether the interconnection procedures provide clear processes for both minor modifications to project design—such as changing the operating settings on a battery storage system, and minor modifications (or upgrades) to the distribution system. Defining processes for each of these types of modifications can help to clarify how and when an applicant can propose project modifications and whether or not they can pay for minor grid upgrades, if necessary, to avoid further study.
Note on Minor System Modifications
During the screening process within initial and supplemental review, utilities can determine whether minor grid upgrades are necessary to address any safety and reliability issues. Allowing interconnection applicants to pay for the upgrades identified during the screening process and avoid lengthy study processes can save time for both utilities and applicants.
One screen that is common in many states’ rules is the “no construction” screen applied during initial review, which fails a project if any utility construction is required, including minor grid upgrades. Though some states may still provide a way for the applicant to pay for minor upgrades and not go through the study process even with the “no construction” screen present, removing it can improve clarity around the process.
Note on Minor Project Modifications
Though the language for this provision seems similar to the criterion on minor system modifications above, minor project modifications are focused on changes or modifications that the applicant can make to the proposed project to avoid or minimize grid impacts and avoid further study. If the system includes energy storage, this could also include changes to the operating characteristics or settings. If states provide detailed information related to grid impacts through screening and study results, an applicant could propose project modifications to resolve any identified issues rather than having to go through additional evaluation or withdrawing the application.
Best Practices
- Allow for minor system modifications during initial and supplemental screening processes
- Allow for minor project modifications in response to screening or study results
- Define “material modification” and include a process for material modification review
Timelines & Efficiency Category
The criteria included above measure whether the interconnection procedures specify timeframes for certain process steps and require efficient timelines for the review of interconnection applications and the stages of the grid impacts review process. Incorporating timelines helps to provide process transparency and set expectations for the amount of time certain steps should take for both interconnection customers and utilities. Though the above provisions are focused on utility actions within the process, states generally provide timeframes for applicant actions as well, which can help to move projects forward in a timely manner or remove them from the project queue if they do not meet required deadlines.
Best Practices
- Specify timelines for all interconnection steps, including application review, technical screening evaluation, study, etc.
- Ensure that the review timelines for simplified, initial, and supplemental review are aligned with best practices
Interconnection Costs & Requirements Category
The criteria under the Interconnection Costs and Requirements category measure whether the interconnection procedures include provisions that help to lower interconnection costs. These provisions specify reasonable fees and requirements for interconnection that can improve cost certainty for applicants.
Note on Site Control Requirements
Site control requirements are a way for states to get applicants to demonstrate that, if approved, their projects can be legally interconnected at a proposed site. These provisions typically require applicants to provide documentation to show either ownership or rights—such as a landowner’s consent—to develop a project at the proposed site, which can demonstrate greater project viability and be a deterrent to speculative interconnection applications that can otherwise contribute to queue backlogs.
Best Practices
- Require documentation to demonstrate site control
- Adopt reasonable application fees for small projects and systems up to 5 MW
- Adopt reasonable costs for supplemental review
- Include an upgrade cost cap
- Adopt a mechanism to share upgrade costs among other applicants or utility customers
- Waive insurance requirements for systems up to 25 kW
- Waive external disconnect switch requirements for systems up to at least 10 kW
Updated Standards & Export Provisions Category
The criteria under the Updated Standards and Export Provisions category measure whether the interconnection procedures incorporate IEEE Standard 1547™-2018, technical requirements, and provisions related to allowing for export control. These provisions help to clarify DER requirements for interconnection as well as export control means that have been vetted and approved for operation.
For more information on incorporating IEEE Standard 1547-2018, see IREC’s Decision Options Matrix for IEEE 1547-2018 Adoption.
For more information on incorporating export control provisions, see the BATRIES Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage.7
Best Practices
- Identify a date by which DERs must comply with IEEE 1547-2018
- Identify or reference an external Commission-approved document that identifies performance categories, voltage regulation, and default settings
- Explicitly define “nameplate capacity” and “export capacity”
- Identify acceptable export control methods, including certified Power Control Systems
Initial Review Screens Category
The criteria under the Initial Review Screens category measure whether the interconnection procedures have incorporated new and revised initial review screens. Each provision in this section is new aside from the penetration screen which was updated to allow for aggregated generation of at least 90 percent of minimum load to pass through the screen rather than 15 percent of annual peak load. These changes and additions represent new and updated practices related to the assessment of grid impacts.
For more information about the screens listed above, see the BATRIES Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage.8
Best Practices
- Incorporate the following screens under the initial review process:
- A penetration screen that allows expedited interconnection up to at least 90 percent of minimum load and is based on export capacity
- A transformer, or shared secondary, screen that evaluates projects based upon the ratio of aggregated DER to transformer nameplate rating being greater than or equal to 65 percent and is based on export capacity
- A clearly defined Line Configuration Screen (LCS) that differentiates requirements for inverter-based DERs vs. rotating DERs
- An inadvertent export screen for systems with non-exporting capacity greater than 250 kW
Supplemental Review Screens Category
The criteria under the Supplemental Review Screens category measure whether the interconnection procedures require a penetration screen based on at least 100 percent of minimum load and an updated voltage and power quality screen within supplemental review. The new criteria change the way systems are evaluated under both of the screens. With the new changes, the penetration screen would evaluate aggregated generation based on export capacity and the voltage and power quality screen would either incorporate an IEEE 1547-2018 reference, use an equivalent voltage screen as IEEE 1547-2018, or not require rapid voltage or flicker screening for solar energy systems.
For more information on using export capacity in the supplemental review penetration screen, see the BATRIES Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage.9
Best Practices
- Adopt a defined supplemental review process that includes the following screens:
- A penetration screen that allows expedited interconnection up to at least 100 percent of minimum load and is based on export capacity
- A voltage and power quality screen that either (a) references IEEE 1547-2018 without reference to IEEE 519, (b) uses an equivalent screen (i.e., 3 percent rapid voltage change limit or Pst voltage flicker calculation), or (c) does not require rapid voltage or flicker screening for solar energy systems
Data Sharing & Reporting Category
The criteria under the Data Sharing and Reporting category measure whether the interconnection procedures require utilities to provide detailed information to help applicants better understand grid conditions, process timelines, project impacts, and cost estimates. These provisions are meant to increase process transparency and access to grid information to better inform siting and project design decisions.
Note on Hosting Capacity Analysis
The incorporation of hosting capacity analysis (HCA) within a state’s screening process is an emerging practice that can improve both transparency and screening accuracy. But in order to use HCA in screening, a state must consider many factors to ensure that HCAs are accurate and designed to be used within the interconnection process. For more information on considerations related to hosting capacity analyses, see IREC’s Key Decisions for Hosting Capacity Analyses.
Best Practices
- Provide detailed screen and study results to applicants, including analysis, supporting data, and justification for failed screens or need for further study and/or grid upgrades
- Provide detailed and itemized cost estimates to applicants
- Require utilities to post an interconnection queue that is updated monthly and allows for the tracking of timelines associated with each step of the process
- Require utilities to offer pre-application reports that cost no more than $500 and include a specified set of data points for a potential project site
- Develop a robust hosting capacity analysis and use it as part of the screening process
- Require utilities to submit an annual report on interconnection timelines and costs that is publicly available
Dispute Resolution Category
The criteria under the Dispute Resolution category measure whether the interconnection procedures require processes to help resolve interconnection disputes. Interconnection disputes can arise over many issues, including timeline compliance and upgrade cost estimates. Providing a clear process and timeframes for dispute resolution is critical to ensuring that issues can be addressed in a timely manner.
Note on Interconnection Forum
Though a dedicated interconnection forum where stakeholders can address emerging challenges on an ongoing basis has not yet been incorporated in any state’s interconnection procedures, it is an emerging practice that can offer regular opportunities to discuss and address interconnection issues.
Best Practices
- Adopt a dispute resolution process that is specific to interconnection disputes
- Offer a regularly-held interconnection forum to address technical and policy issues that arise
- Incorporate a pathway to resolve process or other disputes through the services of an ombudsperson or other facilitator
Footnotes
- The BATRIES project team was led by the Interstate Renewable Energy Council (IREC) and included the Electric Power Research Institute (EPRI), the Solar Energy Industries Association (SEIA), the California Solar & Storage Association (CALSSA), utilities New Hampshire Electric Cooperative Inc. (NHEC) and PacifiCorp, and law firm Shute, Mihaly & Weinberger, LLP (SMW).
- The following organizations reviewed and provided feedback on the 2023 FTG criteria: the Coalition for Community Solar Access (CCSA), the U.S. Department of Energy, the Institute for Local Self Reliance (ILSR), the Smart Electric Power Alliance (SEPA), Sunnova, Sunrun, and Vote Solar. Note: an organization’s mention here does not imply their endorsement of the FTG grades, criteria, or resources.
- The simplified review process is also referred to as “Level 1” review or the “Small, Inverter-based System Review.”
- The expedited review process is also referred to as “Level 2” or “Fast Track” review.
- The term disinvested community is used here to “refer to communities that (1) receive inadequate social and economic services and resources and (2) experience consequences or impacts from policy decisions more acutely due to historic marginalization. These communities also often face high barriers to participation in decision-making processes. Communities of color and Indigenous communities, low-income communities, and immigrant communities are some groups that are more likely to be disinvested. Other terms that are commonly used to refer to communities experiencing similar dynamics include marginalized communities, environmental justice communities, and disadvantaged communities. These terms are often used differently in different settings, and no one term is appropriate for all communities.” This definition is taken from the American Council for an Energy-Efficient Economy (ACEEE)’s Leading with Equity Initiative: Year Two Recap and Next Steps.
- New Mexico Administrative Code, Title 17, Chapter 9, Part 568, Section 19, https://www.srca.nm.gov/parts/title17/17.009.0568.html
- Interstate Renewable Energy Council, Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage, pp. 45-55 (March 2022). https://energystorageinterconnection.org/resources/batries-toolkit/
- Interstate Renewable Energy Council, Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage, pp. 62-66 and 132-135 (March 2022). https://energystorageinterconnection.org/resources/batries-toolkit/
- Interstate Renewable Energy Council, Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage, pp. 62-63 (March 2022). https://energystorageinterconnection.org/resources/batries-toolkit/