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MISO’s DER Affected Systems Study Process: Unpacking the Controversy in Minnesota
The Midcontinent Independent System Operator (MISO) is currently engaged in an important process regarding Distributed Energy Resources (DERs)—specifically, the DER Affected Systems Study (AFS). This initiative has gained momentum following the Federal Energy Regulatory Commission’s (FERC) approval of MISO’s compliance with its Order 2222 filing. Notably, MISO had initiated the DER AFS process prior to receiving FERC approval, which now solidifies the process’s legitimacy and outlines its framework within MISO’s tariff.
However, this development has sparked confusion among Community Solar Garden (CSG) developers, particularly because Xcel Energy has also been conducting assessments for DER interconnections. The existence of dual studies—one from Xcel and another from MISO—has led to concerns from developers and clean energy organizations, prompting them to raise their grievances with the Minnesota Public Utilities Commission (PUC). These stakeholders argue that Xcel’s transmission system impact study overlaps with MISO’s DER AFS process, potentially causing delays in the interconnection timeline for CSGs in Minnesota. This scenario may have broader impacts on other DER interconnections managed by MISO.
Key Areas of Disagreement
The disagreements between Xcel and the clean energy organizations span eight primary categories:
1. Definition of Transmission Provider in Minnesota Distributed Energy Resource Interconnection Process
Xcel maintains that it fits the definitions of both Transmission Owner and Transmission Provider within the Minnesota Distributed Energy Resource Interconnection Process (MN DIP), which allows it to perform internal transmission studies (ITS). Conversely, the CEO contends that Xcel serves purely as the Area Electric Power System (EPS) Operator and requires designation by MISO to conduct transmission studies.
This differentiation is significant for the CEO, as it suggests that Xcel could derive distribution system upgrades from its own studies while MISO identifies the need for transmission system upgrades, complicating matters for CSG developers, who do not desire to participate in the MISO market.
Prior to the discussions surrounding FERC Order 2222 compliance, MISO had taken a more relaxed approach toward distribution-connected interconnections, allowing transmission owners to work directly with distribution utilities. However, due to an expected surge in DER interconnections—partially influenced by Xcel’s early compliance arguments—MISO established the new DER AFS process.
2. Legal and Regulatory Authority
Xcel argues that the MN DIP does not limit the role of Transmission Provider to MISO alone. In contrast, the CEO insists that any changes to this role must receive approval from the Commission to avoid violating Minnesota statute.
Within Minnesota’s wholesale market ecosystem, “Transmission Provider” typically refers to MISO, which manages transmission in a non-discriminatory manner. Transmission owners like Xcel have delegated their functional authority to MISO, a dynamic governed by the MISO Transmission Owners Agreement. MISO’s planning for regional transmission, as seen in its MISO Transmission Expansion Plan (MTEP), underlines its role as the transmission provider, with Xcel acting as a transmission owner. The friction arises as Xcel asserts dual roles, which if validated by the Minnesota PUC, would enable Xcel to conduct its own transmission impact studies, complicating matters for CSG developers.
3. Duplication of MISO AFS Study
Xcel argues that ITS should only be implemented where MISO does not carry out a study, utilizing Daytime Minimum Load (DML) as a trigger, while MISO relies on peak load. Xcel maintains that this approach does not duplicate the MISO AFS study.
4. Study Triggers
Defending its use of DML, Xcel labels it a necessary measure for safety and reliability. The company critiques MISO’s choice of peak load as overly simplistic. The CEO counters that DML was dismissed during MISO’s stakeholder deliberations, particularly unsuitable for DERs lacking battery storage.
5. NERC Compliance
Xcel claims that both MISO and itself, as Transmission Planners, are required under NERC standards to conduct studies based on differing triggers. However, the CEO questions the necessity of DML for MISO, implying potential overinterpretation of NERC directives on Xcel’s part.
6. Cost and Impact on DER Programs
Xcel argues that ITS is crucial for maintaining system reliability and isn’t redundant, expressing a willingness to enhance transparency. In contrast, the CEO expresses concern that ITS could lead to significant costs and delays, particularly impacting Low- and Moderate-Income solar projects and Distributed Solar Energy Standard (DSES) initiatives.
7. Modification to MN DIP
Xcel claims that no modifications to the MN DIP are warranted since ITS aligns with current regulations. The CEO, however, believes that ITS diverges from established MN DIP protocols and necessitates formal assessment before moving forward.
8. Stakeholder Process and Transparency
While Xcel indicates an openness to engage in discussions regarding ITS adjustments, it opposes any stay, citing compliance risks under NERC. In response, the CEO has called for a formal investigation and stakeholder engagement by the Minnesota PUC before proceeding with ITS due to perceived shortcomings in Xcel’s communication and rationale.
The resolution of these contentious issues will be crucial for streamlining the interconnection process for CSGs and potentially shaping the future landscape of DER integration across Minnesota and MISO at large.
Source
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