Locational Requirements. NYISO DER Aggregations must be at a single NYISO-identified Transmission Node that will be as large as possible while accounting for the efficiency of the NYISO-administered markets and the reliability of the system. FERC wants to understand the process for identifying such nodes in detail. Future filers can expect that any locational limitation must be fully developed and described in detail, particularly if the process is located in a business practice manual (BPM) rather than the tariff.
Distribution Factors and Bidding Parameters. CAISO has a requirement relating to DER Aggregations providing net response at its Pricing Node (PNode) and distribution factors in a Master File which governs various bid components. Here, the Commission questions focused on process rather than whether the substance of the requirement was questionable.
Information and Data Requirements. The CAISO has requirements largely located in a BPM related to the detailed information needed about each DER in an Aggregation. FERC’s extensive questioning on the subject included many “whys” such data requirements existed. It was a bit unclear whether FERC’s concern was the location of the requirements (a BPM) or the nature of the information, which seemed to be the type of information any ISO would require so that it could properly account for and model DER Aggregation. FERC also asked about the Aggregator’s CAISO Scheduling Coordinator’s need to retain auditable data and comparability. Here, the concern seemed less about the requirement than whether it was similar to other Scheduling Coordinator data retention requirements.
Metering and Telemetry System Requirements. Both NYISO and CAISO were asked about the metering and telemetry requirements imposed on DER Aggregators. FERC was most interested in relationship between the Distribution Utility’s role in meter data collection process and other details as to how data will be collected, including whether direct measurement would always be required. Given that a Distribution Utility’s role in metering may vary quite widely based on factors such as the nature of the DER, whether it has load behind its retail meter, its interconnection obligations, and whether the state oversees metering, the question on the role of the Distribution Utility in metering may be very difficult for an ISO to answer. At least the NYISO and CAISO, as single-state ISOs, have a more narrow task than future filers that may be dealing with a dozen or more states with differing state commission rules applying to the regulated Distribution Utilities as well as an even larger number of unregulated Distribution Utilities. FERC’s main concern may be duplicative metering. The Commission also seems interested in why various size thresholds exist. Where size thresholds exist, explanation is key even if the threshold is quite longstanding.
Coordination Between the ISO, Aggregator, and Distribution Utility. FERC’s questions to both ISOs on the role of the main players appear largely rooted in its concern that Distribution Utilities will thwart DER Aggregation. Although Order No. 2222 provides Distribution Utilities review rights over DER Aggregations as to safety and reliability as to the distribution system, FERC expects the ISOs to define such rights in some detail, a role that an ISO may be loathe to take on given a lack of familiarity with distribution systems generally. The Commission seems particularly concerned that single DER additions to Aggregations may cause lengthy re-evaluations. Resolving disputes also was a common concern. Future filers will likely have to spill extensive ink on such processes that may not yet be well developed due to a lack of experience; i.e., Distribution Utilities may not yet know what issues may even arise, but ISOs will need to try and address any potential issues.
Ongoing Operational Coordination. As to ongoing operations, FERC is concerned about information flow between the Distribution Utility and ISO as well as protocols and procedures used when a Distribution Utility overrides an ISO dispatch, as presumably will be its right under the Distribution Utility’s interconnection agreement with each DER. Transparency is an issue as to such coordination and communication. Once again, the devil is in the details, which may be difficult to describe, particularly by ISOs that have not had any experience with DER Aggregations.
Role of Relevant Electric Retail Regulatory Authorities. FERC permits voluntary regulating authority participation in the coordination and participation of DERs and both ISOs were questioned in detail about various roles that these authorities ay play. These questions are difficult given that an ISO may dealing with dozens of authorities, some of which will play varying roles. FERC is asking specific questions as to what each authority plans to do, a question that is seemingly only answerable by the regulating authority itself, assuming the regulating authority even intends to address the issue before a DER Aggregation exists. It is not clear that future filers can do more than identify what a regulatory authority may possibly do, as each regulatory authority may have varying authority itself. Certainly, how regulatory authorities participated in any stakeholder process should be described to demonstrate that their voices are being heard.
Modifications to List of Resources. NYISO was questioned about the required list of DERs in each Aggregation and updates to the list. As noted above, processes involving changes relating to a single DER in an Aggregation are of keen interest presumably due to concerns over delays. FERC does not expect actions, such as the deletion of a single DER from an Aggregation, to trigger a lengthy review process.
Summary. The Deficiency Letters have given future filers (and protestors) a road map as to what it expects in a satisfactory filing. The concern raised by the letters is that FERC is seeking some information an ISO simply may not now nor ever possess. Multiple “compliance filing” rounds are thus to be expected to answer FERC’s questions to its satisfaction. Given FERC’s lack of jurisdiction over regulatory authorities and many Distribution Utilities, the ISOs bear a heavy compliance burden to describe the roles of entities they do not control.