Tenaska Clear Creek Wind, LLC v. Southwest Power Pool, Inc.

• Decision Date: 16 February 2023
• Docket Number: EL21-77-003
• Citation: 182 FERC ¶ 61, 084
• Parties: Tenaska Clear Creek Wind, LLC v. Southwest Power Pool, Inc.
• Court: Federal Energy Regulatory Commission

182 FERC ¶ 61,084

Tenaska Clear Creek Wind, LLC
v.
Southwest Power Pool, Inc.

No. EL21-77-003

United States of America, Federal Energy Regulatory Commission

February 16, 2023

Before Commissioners: Willie L. Phillips, Acting Chairman; James P. Danly, Allison Clements, and Mark C. Christie.

ORDER ADDRESSING ARGUMENTS RAISED ON REHEARING AND DENYING MOTION FOR STAY

Debbie-Anne A. Reese, Deputy Secretary.

1. This proceeding arises from Tenaska Clear Creek Wind, LLC's (Tenaska) complaint (Complaint) challenging Southwest Power Pool, Inc.'s (SPP) assignment of certain network upgrade costs to Tenaska's Clear Creek Wind Project (Project) based on SPP's affected system study process. The Commission previously directed SPP to conduct a restudy because it found that SPP's use of certain models to assign network upgrade costs was unduly discriminatory or preferential.^[1]

2. On March 11, 2022, as revised on May 13, 2022, SPP submitted compliance filings with the results of the restudy directed by the Commission (2022 Restudy). On September 9, 2022, the Commission issued an Order on Compliance and Addressing Arguments Raised on Rehearing, finding that SPP complied with the Commission's directive to restudy the Project and that the assignment of network upgrade costs to the Project pursuant to the 2022 Restudy was just and reasonable, not unduly discriminatory or preferential, and consistent with the "but for" cost allocation principle.^[2]

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3. On October 7, 2022, Tenaska timely sought rehearing of the Compliance and Rehearing Order. Additionally, on October 7, 2022, Tenaska filed a motion for stay of the Compliance and Rehearing Order.

4. Pursuant to Allegheny Defense Project v. FERC,^[3] the rehearing request filed in this proceeding may be deemed denied by operation of law. However, as permitted by section 313(a) of the Federal Power Act (FPA),^[4] we are modifying the discussion in the Compliance and Rehearing Order and continue to reach the same result in this proceeding, as discussed below.^[5] We also deny the motion for stay.

I. Background A. Tenaska's Interconnection Request

5. In May 2017, Tenaska submitted an interconnection request for the Project-a 242 MW wind generating facility-to interconnect to the Associated Electric Cooperative, Inc. (AECI) transmission system and requested a Network Resource Interconnection Service (NRIS) level of interconnection service.^[6] Following the submission of Tenaska's interconnection request, AECI identified Midcontinent

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Independent System Operator, Inc. (MISO) and SPP as potential affected systems.^[7] In its affected system study, MISO determined that no network upgrades were necessary on its transmission system to accommodate the interconnection of the Project to the AECI transmission system.

B. SPP's Affected System Study Process

6. SPP conducts its affected system study process,^[8] which evaluates the impacts on SPP's transmission system of projects interconnecting to a neighboring transmission system, in coordination with its process for studying requests for interconnection to its own transmission system. Interconnection customers seeking to connect to SPP's transmission system submit their interconnection requests to SPP. SPP assigns each interconnection request an initial queue position and then studies these interconnection requests in accordance with its generator interconnection procedures, contained in Attachment V of the SPP Open Access Transmission Tariff (Tariff). All valid interconnection requests submitted during the same Definitive Interconnection System Impact Study (DISIS) queue cluster window become part of the same DISIS study cluster, and SPP evaluates each study cluster to determine whether network upgrades are necessary to accommodate the requests in the cluster.^[9] SPP's practice is to study interconnection requests based on the requested level of interconnection service (i.e., Energy Resource Interconnection Service (ERIS)^[10] or NRIS) on the host transmission system.^[11]

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7. When conducting an interconnection study, SPP uses its integrated transmission planning (ITP)^[12] reliability assessment models as the "base case" models in studies. SPP then adds to the base case interconnection requests for proposed projects and any higher-queued interconnection requests that were submitted prior to the interconnection requests being studied to create the "pre-transfer case." Next, SPP adds to the pretransfer case the current interconnection requests being evaluated in the same system impact study to establish the "transfer case."^[13]

8. In the transfer case, SPP studies interconnection requests by dispatching the higher-queued and current interconnection requests in specific dispatch scenarios. Once SPP develops the transfer case dispatch scenarios, it performs a contingency analysis for each scenario. If SPP identifies a thermal overload constraint through the contingency analysis, and the interconnection request impacts the constrained facility by the applicable transfer distribution factor (TDF),^[14] SPP requires a network upgrade to mitigate the constraint.^[15]

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9. SPP assigns responsibility for network upgrades needed to mitigate a constraint based on whether an interconnection request impacts the constraint by at least the applicable TDF threshold and if the transmission facility is overloaded greater than 100% of its line rating. The applicable TDF thresholds are based on the type of interconnection service requested by the interconnection customer-ERIS or NRIS-and are documented in SPP Business Practice 7250.^[16] If the impact of an interconnection request is below the TDF threshold, then SPP considers the generating facility's impact de minimis (even if a transmission line is overloaded beyond its line rating) and does not assign network upgrades for that transmission facility to the interconnection customer.^[17]

C. SPP's Affected System Study of Tenaska's Project

10. In October 2018, SPP issued its first affected system impact study for the Project, which identified $31.2 million in network upgrades on the SPP transmission system, using SPP's 2017 ITP models, to accommodate the interconnection of the Project to the AECI transmission system. Following revisions in November 2018 and March 2019, SPP issued an affected system facilities study in April 2019 that identified approximately $33.5 million in network upgrades assigned to the Project. Because Tenaska requested NRIS level of interconnection service on the AECI transmission system, SPP conducted affected system analyses assuming that the Project is dispatched under both ERIS and NRIS standards. In these initial studies, SPP identified only network upgrades needed to resolve constraints when modeling for ERIS.^[18] No additional upgrades were identified as necessary from SPP's modeling of the Project using NRIS standards.^[19] Tenaska started constructing the Project in Spring 2019.^[20]

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D. SPP's Restudy of Tenaska's Project

11. In November 2019, SPP communicated to Tenaska that it intended to restudy the Project. According to Tenaska, SPP indicated that the restudy was due to the withdrawal of a higher-queued project-Project J570-from the interconnection queue. SPP disputed Tenaska's description of the purpose of the restudy and asserted that the restudy was due to the withdrawal of several higher-queued projects from the MISO DPP-2017-FEB-West study cluster, one of which was Project J570, totaling 1,173.8 MW.^[21] In May 2020, SPP informed Tenaska that, because the models used for the initial studies were over a year old, SPP intended to conduct the affected system restudy using the 2019 ITP models. The Project began commercial operation in May 2020.^[22] Tenaska states that the Project has been curtailed pending the completion of network upgrades that are the subject of this proceeding.^[23]

12. In November 2020, SPP provided the results of its first affected system restudy, which showed that $763 million in required network upgrades to the SPP transmission system were needed to accommodate the interconnection of the Project to the AECI transmission system. SPP also indicated for the first time that NRIS network upgrades were necessary. In explaining the cost increase, SPP informed Tenaska that it had inadvertently omitted approximately 4.5 GW of higher-queued generation on the MISO transmission system in both the initial affected system studies for the Project and in the studies of the DISIS-2016-002 study cluster. Specifically, SPP determined that although the ERIS models used in the initial affected system impact study included the 4.5 GW of higher-queued generation, this generation was missing from the 2017 ITP models SPP used to conduct the NRIS portion of the initial affected system impact study. SPP stated that due to this omission, it deemed the initial affected system impact study invalid and decided to use the 2019 ITP models for the restudy.^[24]

13. In December 2020, SPP provided updated affected system restudy results, which lowered Tenaska's cost responsibility to $106.8 million. SPP again updated the restudy results in January and February 2021, lowering the amount to $91 million. In March 2021, SPP posted affected system restudy results assigning a total of approximately $99 million in network upgrades to the Project, comprised of $34 million

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in network upgrade costs necessary to provide ERIS-level service and an additional $66 million in network upgrade costs necessary to provide NRIS-level service.^[25]

E. Complaint and Complaint Order

14. On May 21, 2021, Tenaska filed the Complaint against SPP alleging that SPP performed a flawed restudy of the Project as part of SPP's affected system study process and erroneously assigned Tenaska approximately $66 million in NRIS network upgrade costs. For relief, Tenaska requested that the Commission require the $66 million in costs be rolled into...