Chapter VII Key Takeaways

Storage interconnection faces a key barrier when it comes to project modifications. As projects go through the interconnection process, utilities may identify system impacts that require distribution system upgrades. But the interconnection review process is not designed to allow a customer to undertake project design changes to avoid those impacts without forfeiting their place in the interconnection queue. Chapter VII: Pathways to Allow for System Design Changes During the Interconnection Review Process to Mitigate the Need for Upgrades describes this barrier and provides recommendations on how rule language can be changed to accommodate the type of project modifications that an ESS system could make to avoid the need for upgrades during the interconnection process.

Recommended Pathways to Allow for System Design Changes During the Interconnection Review Process to Mitigate the Need for Upgrades:
1. Interconnection procedures should be revised to provide more data on the reasons for which a project fails screens. To ensure that the customer has enough information to make design decisions, the interconnection procedures should give as specific guidance as possible on what information results should convey to the interconnection applicant, including the specific screens that the project failed and the technical reason(s) for failure, as well as details about the specific system threshold or limitation causing the failure.
 
2. Screening results should provide relevant and useful data, to enable the customer to ascertain exactly what changes to the DER system could allow it to pass the screen and avoid the need for upgrades. Chapter VII includes a list of preferable screen results data.
 
3. Impact study results should provide an analysis of potential changes to the DER system that could eliminate or reduce the need for upgrades. Utilities should provide, at a minimum, a limited analysis of alternative DER configurations, ideally during the normal timeframe of the study process (rather than requiring restudy after study results are delivered).
 
4. Interconnection procedures should have well-documented sections that provide guidance on whether and how design changes can be accommodated, in order to allow an interconnection applicant to undertake design modifications to mitigate impacts without submitting a new interconnection application.
 
5. During the Supplemental Review process, additional screens are applied that may provide further detail on whether system upgrades are required and provide an opportunity to identify if modifications could address the constraints. Interconnection procedures should allow for a short period of design change and review, as necessary, to help projects move forward quickly with minimal effects on the queue.
 
6. Design changes should also be permitted within the full study process. If the utility has already studied alternative configurations during the impact study process, as described above, the utility and developer would have the necessary information to discuss design changes. During a scoping meeting, the developer and utility should agree to evaluate up to three different options, one being the original design and the other two containing system changes.
 
7. If the utility and developer have already evaluated design options and major design modifications require further study, they can be addressed through post-results modifications. Due to high interconnection cost estimates, even with the options studied per the previous recommendation, modifications to the DER system beyond those alternate options may be desired. As such, interconnection rules should include an explicit process for modifications after study results are delivered.

A. Introduction and Problem Statement

As projects go through the interconnection process, utilities may identify system impacts caused by the project that necessitate distribution system upgrades. Some storage projects can make changes in proposed charging and discharging behavior, inverter functions, or export amounts that could mitigate the need for upgrades identified by the utility. Since the system impacts may not be known until after the screening or study process, interconnection customers would like to be able to modify projects after receiving results without submitting a new application and losing their interconnection queue position. However, the interconnection review process typically is not designed to allow for customers to undertake project design changes that could help to avoid grid upgrades and minimize interconnection delays during the review process.

In most jurisdictions, if the utility finds that grid upgrades are needed for a project to proceed, the customer is often given two choices: (1) to pay for the upgrades, or (2) to withdraw the project, forfeit their place in the interconnection queue, and submit a new design and application. Most procedures do not expressly allow design changes as a third option. The time delays and costs associated with this practice can be substantial for both utilities and customers.

From the customer perspective, the major barriers to a more efficient interconnection review process include: 1) the lack of data access that may help them design and site projects to avoid grid constraints at the outset or redesign utility-reviewed projects to mitigate impacts, and 2) the lack of clear steps that could enable them to address system impacts following utility review and understand when restudy is required. From a utility standpoint, the main challenge is the staff time required to review resubmitted applications, screen projects for impacts, or engage in back-and-forth dialogues with customers to resolve outstanding issues. In addition, utilities and interconnection customers as a group may be reluctant to employ informal resolution approaches for fear that customers farther back in the queue may object to accommodating customers who are given an opportunity to make revisions to a project without surrendering their queue position. Utilities also must strive to provide equal treatment to all customers.

Some states and utilities have incorporated new processes to ensure sufficient data is provided with screening and study results and to provide customers with an option to resolve interconnection issues via certain allowed design changes while remaining in the queue. Based on current practices as well as information provided by developers and utilities, it is recommended these features be included in interconnection rules and related procedures in order to increase the successful interconnection of DERs. Storage capabilities to modify export can be leveraged to tailor the DER system to grid constraints when using these practices.

Download the chapter file below to read more. Or download the full Toolkit and Guidance for the Interconnection of Energy Storage and Solar-Plus-Storage for all chapters and recommendations.

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