{"document":{"slug":"filing-20261013-5440","title":"Motion for Leave to Answer and Answer of Midcontinent Independent System Operator Inc. to the Comments and Protests re the proposal to establish Interconnection Reliability Requirements for Large Loads","issued":"2026-10-13","accession":"20261013-5440","docket":"ER26-3650-000","group":"MISO filings","filer":"Midcontinent Independent System Operator Inc.","kind":"comments","file":"sources/originals/20261013-5440_01.pdf","url":"https://elibrary.ferc.gov/eLibrary/filelist?accession_Number=20261013-5440","sha256":"52151a0f91fa5675f4e97f9b1e18d311818bea79b25f2d892b907201553342b5","pages":35,"tokens":9521,"emptyPages":[]},"pages":[{"page":1,"startToken":0,"endToken":325,"text":"UNITED STATES OF AMERICA \nBEFORE THE \nFEDERAL ENERGY REGULATORY COMMISSION \n \nMidcontinent Independent System  \n \n) \nOperator, Inc.  \n \n \n \n \n) \n \nDocket No. ER26-3650-000 \n \n \n \n \n \n \n \n) \n \nMOTION FOR LEAVE TO ANSWER AND ANSWER OF THE MIDCONTINENT \nINDEPENDENT SYSTEM OPERATOR, INC.  \n \nThe Midcontinent Independent System Operator, Inc. (“MISO”) submits1 this Motion for \nLeave to Answer and Answer (“Answer”) to the comments and protests filed in the above-\ncaptioned docket by the Midwest TDUs,2 MISO Transmission Owners (“MISO TOs”), the North \nAmerican Electric Reliability Corporation and Regional Entities (“NERC et al.”), the Organization \nof MISO States, Inc. (“OMS”), Entergy Services, LLC (“Entergy”), Google LLC (“Google”), the \nLarge Energy Users,3 the Public Interest Organizations (“PIOs”),4 the Joint Consumer Advocates,5 \nthe Data Center Coalition (“DCC”), Rowan Digital Infrastructure, LLC (“Rowan”), and Verrus, \nLLC (“Verrus”).  \n \n1  \nSee Rules 212 and 213 of the Rules of Practice and Procedure of the Federal Energy Regulatory Commission \n(“FERC” or “Commission”) (herein referred to the “Rules of Practice and Procedure”), 18 C.F.R. §§ 385.212 and \n213 (2026).  \n2  \nThe Midwest TDUs consist of Central Municipal Power Agency/Services (“CMPAS”), Indiana Municipal Power \nAgency (“IMPA”), Missouri Joint Municipal Electric Utility Commission (“MJMEUC”), and WPPI Energy \n(“WPPI”). \n3  \nThe Large Energy Users consist of the Coalition of MISO Transmission Customers, Illinois Industrial Energy \nConsumers, Association of Businesses Advocating Tariff Equity (“ABATE”), NIPSCO Large Customer Group, \nLouisiana Energy Users Group, and Texas Industrial Energy Consumers. \n4  \nThe PIOs consist of Sierra Club, Natural Resources Defense Council, Environmental Law & Policy Center, Clean \nWisconsin, Union of Concerned Scientists, Sustainable FERC Project, and Fresh Energy. \n5  \nThe Joint Consumer Advocates consist of the Iowa Office of Consumer Advocate (“Iowa OCA”), Office of the \nIllinois Attorney General (“IL OAG”), Illinois Citizens Utility Board (“IL CUB”), Michigan Attorney General, \nMichigan Citizens Utility Board (“MI CUB”), Minnesota Department of Commerce (“Commerce”), Citizens \nUtility Board of Minnesota (“MN CUB”), Wisconsin Citizens Utility Board (“WI CUB”), Citizens Action \nCoalition of Indiana, Inc., and Alliance for Affordable Energy."},{"page":2,"startToken":325,"endToken":624,"text":"2 \nThe comments reflect support for MISO’s Interconnection Reliability Requirements \nProposal (“IRR Proposal”) to establish reliability requirements for Large Loads, while several \nparties request modifications or clarification regarding specific aspects of the proposal.6  The \npleadings reflect broad agreement on the central point underlying the IRR Proposal: the \nunprecedented scale, concentration, and operating characteristics of emerging Large Loads require \nadditional visibility and operational reliability tools now.  Several parties expressly support the \nproposal or its core reliability framework, while other parties seek clarification or additional detail \nregarding implementation.7  Notably, only one protest requests the revisions to be rejected and \nMISO directed to file revised requirements by the end of 2027.8  And one comment requests that \nthe revisions be rejected without prejudice to MISO filing a revised proposal.9  MISO believes the \ncomments reinforce that MISO has put forth a balanced proposal that provides an opportunity to \ncontinue to move forward with the Commission’s desired outcome to support the appropriate \nintegration of large loads onto the system in a reliable, efficient and transparent way.  \nThe comments and protests do not demonstrate that MISO’s IRR Proposal is unjust or \nunreasonable.  Several parties propose modifications to the definitions, transition provisions, or \nimplementation of the proposed Large Load requirements, while others request that additional \nrequirements or implementation details be included in the Tariff rather than MISO’s Business \nPractices Manuals (“BPMs”).10  These comments present alternative approaches to particular \n \n6  \nMISO Transmission Owners Comments at 3, 6-7; Organization of MISO States Comments at 2-7; Verrus \nComments at 2-4; Google Comments at 1-5; NERC et al. Comments at 6-9. \n7  \nId. \n8  \nPIO Protest at 2. \n9  \nDCC Protest at 25. \n10  DCC Protest at 3-4; Google Comments at 2,7; Entergy Protest at 4-17; Southern Regulators Protest at 1-2; PIO \nProtest at 17-22."},{"page":3,"startToken":624,"endToken":874,"text":"3 \naspects of MISO’s proposal, but do not establish that the framework proposed by MISO fails to \nsatisfy the requirements of Section 205 of the Federal Power Act.11  MISO’s proposal establishes \nrequirements addressing the necessary visibility into Large Loads and their operation, including \ninformation, modeling, telemetry, and forecasting requirements, while also proposing specific \nrequirements necessary to address the operational characteristics of Computational Loads.12 \nThe Commission should therefore accept the IRR Proposal without delaying its \nimplementation or requiring MISO to expand this proceeding to resolve distinct large-load, \ntransmission-service, or generator-interconnection issues.13  Accordingly, MISO respectfully \nrequests that the IRR Proposal be accepted without modification and grant the requested effective \ndate of December 4, 2026. \nI. \nBACKGROUND \nThe IRR Proposal is an important near-term component of MISO’s broader response to \nrapidly accelerating Large Load development.  MISO’s 2026 Long-Term Load Forecast shows \nload growth at levels not experienced in decades, driven in substantial part by data centers, \nadvanced manufacturing, and other large-load additions, some of which seek to develop on \ntimelines materially shorter than traditional generation and transmission infrastructure.14  The \nNorth American Electric Reliability Corp (“NERC”) likewise has identified emerging \ncomputational loads as an increasing Bulk-Power System reliability consideration because \nconventional planning and operational assumptions may not capture the behavior of facilities that \n \n11  16 U.S.C. § 824d. \n12  IRR Proposal at 10-12, 19-26; Proposed Tariff §§ 37A.1-37A.8; Li Testimony at 12-14, 28-34. \n13  IRR Proposal at 4. \n14  IRR Proposal at 2, 7-8; Li Testimony at 5-10."},{"page":4,"startToken":874,"endToken":1148,"text":"4 \nare very large, capable of rapid demand changes, and increasingly dependent on power-electronic \nequipment.15  \nThe Commission’s June 18, 2026 Show Cause Order preliminary found that MISO’s Tariff \nappears to be unjust and unreasonable because it lacks sufficiently clear and consistent Tariff \nprovisions that address certain aspects of the process to provide transmission service to Eligible \nCustomers on behalf of large loads, including: (1) a definition of large load sufficient to capture \nloads that present the unique challenges described in the Show Cause Order; and (2) ongoing \noperational requirements for transmission customers serving large loads necessary to ensure \nreliable operation of the transmission system.16  In response, MISO proposed Tariff revisions \nestablishing ongoing operational requirements for transmission customers taking service on behalf \nof Large Loads, including hourly forecasts, telemetry and other visibility data, communications, \nmonitoring equipment, ramp rates, and ride-through requirements.17  The IRR Proposal responds \ndirectly to those concerns through four complementary categories of requirements: (i) visibility \nrequirements, including data, modeling, telemetry, and forecasting; (ii) PMU requirements for \nComputational Loads; (iii) ramp requirements for Computational Loads; and (iv) ride-through \nrequirements for Computational Loads.18  \nThis IRR Proposal has substantial support.  The MISO Transmission Owners support the \nIRR Proposal as a just and reasonable framework that complements MISO’s other Large Load \n \n15  IRR Proposal at 2-3, 7-8; NERC, Essential Action to Industry - Computational Load Modeling, Studies, \nInstrumentation, Commissioning, Operations, Protection, and Control May 4, 2026. \n16  Show Cause Order at P 57. \n17  Midcontinent Indep. Sys. Operator, Inc., 195 FERC ¶ 61,212, at P 64 (2026) (“Show Cause Order”); IRR Proposal \nat 6. \n18  IRR Proposal at 3-4, 9; Li Testimony at 10-11."},{"page":5,"startToken":1148,"endToken":1422,"text":"5 \ninitiatives.19  OMS generally supports the framework, including visibility, PMU, ramp, and ride-\nthrough requirements, and supports implementing requirements now while broader NERC \nstandards continue to develop.20  Verrus supports MISO’s risk-scaled applicability and its use of \nthe Tariff for core obligations with BPMs for implementation detail.21  NERC and the Regional \nEntities recognize that the IRR Proposal appears generally consistent with pending Reliability \nStandards efforts and describe MISO’s work as one contribution to advancing reliability while \nNERC and industry work in parallel.22  \nMISO recognizes that NERC and industry are working to mitigate the immediate reliability \nrisks associated with computational load and does not intend the IRR Proposal to unnecessarily \ndiverge from NERC’s developing framework.  At the same time, MISO recognizes that some \nNERC requirements, such as ride-through, will not begin development until 2027 and the urgency \nof immediate reliability risks necessitates NERC, MISO, and other stakeholders to act in parallel \nrather than sequentially; NERC recognizes this urgency as well.23  MISO has coordinated its \nproposal with emerging NERC guidance, and its stakeholder process expressly considered \nNERC’s Large Load and Computational Load work.24  NERC Project 2026-02 is itself moving \nrapidly: the initial posting was authorized August 19, 2026, and initial ballots on the first set of \nComputational Load standards concluded September 18, 2026.25  MISO will continue coordinating \n \n19  MISO Transmission Owners Comments at 3, 6-7. \n20  OMS Comments at 2-7. \n21  Verrus Comments at 2-4. \n22  NERC et al. Comments at 6-9. \n23  NERC et. al. Comments at 7. \n24  IRR Proposal at 28-30; Li Testimony at 36-39. \n25  NERC, Project 2026-02 Computational Loads, Project Status (accessed Oct. 6, 2026)."},{"page":6,"startToken":1422,"endToken":1718,"text":"6 \nwith NERC and will evaluate conforming changes as NERC’s registration criteria and Reliability \nStandards become final.  \nWith the IRR Proposal, MISO is proposing to implement one part of a reliability-based \nframework to support the interconnection and ongoing operational challenges of Large Loads \nwithin the MISO region.  The objective is to establish scalable, technically justified, and risk-\ninformed expectations that improve visibility into large load behavior, support planning and \noperational readiness, and preserve reliable operation of the Transmission System and Bulk \nElectric System.  The proposed framework is intended to complement existing and developing \nMISO planning, interconnection, and operational processes and align, to the extent practical, with \nemerging NERC guidance and industry practices. \nII. \nMOTION FOR LEAVE TO FILE ANSWER \n \n \nUnder the Commission’s rules, answers to protests generally are not permitted.26  \nNonetheless, the Commission waives this requirement where an otherwise prohibited answer \nwould clarify the issues under consideration, ensure completeness of the record or assist the \nCommission in its decision-making.27  \nThe comments and protests raise issues concerning the scope of MISO’s Large Load and \nComputational Load definitions, the transition framework, the division of requirements between \nthe Tariff and Business Practices Manuals (“BPMs”), the responsibilities of Transmission \nCustomers, and the operational forecasting requirements.  This Answer clarifies the record on \n \n26  See Rule 213 of the Rules of Practice and Procedure, 18 C.F.R. § 385.213(a)(2) (2026). \n27  See, e.g., Midcontinent Indep. Sys. Operator, Inc., 169 FERC ¶ 61,173, at P 24 (2019) (accepting MISO’s answer \nto protests because it assisted FERC in the decision-making process); Texas Eastern Transmission, LP, 122 FERC \n¶ 61,205, at P 8 (2008) (accepting answer that completed the record); California Indep. Operator Corp., 105 \nFERC ¶ 61,284 at P 10 (2003) (accepting MISO’s answer that clarified the issues)."},{"page":7,"startToken":1718,"endToken":1998,"text":"7 \nthose issues and explains why the IRR Proposal is just and reasonable as filed.  MISO therefore \nrespectfully requests waiver of Rule 213(a)(2) and acceptance of this Answer. \nIII. \nANSWER \nA. \nMISO’S LARGE LOAD AND COMPUTATIONAL LOAD DEFINITIONS ARE JUST AND \nREASONABLE. \n \n1. \nThe 50 MW Large Load threshold is reasonable, administratively \nclear, and consistent with emerging industry practice. \n \nThe Commission should accept MISO’s Large Load definition as just and reasonable. As \nexplained below, the 50 MW threshold — measured at Points of Withdrawal for facilities located \nat a single substation— (1) provides an objective, administrable screen for Large Loads; and (2) \nreflects specific characteristics of MISO’s transmission system; and (3) ensures necessary \nvisibility through Section 37A; and (4) does so without a requiring a separate voltage criterion \nbecause applicability is already defined at the Transmission System boundary.   \nFirst, MISO proposes to define a Large Load as Load with Demand of 50 MW or more \nassociated with a facility or aggregation of facilities located at a single substation behind one or \nmore Points of Withdrawal from the Transmission System and owned, operated, or controlled by \na single entity or a coordinating group of entities; Load used exclusively for charging an Electric \nStorage Resource is excluded.28  MISO determined 50 MW was the appropriate threshold based \non emerging industry practices, the reliability needs of the MISO region, and stakeholder \nfeedback.29  For example, Southwest Power Pool’s (“SPP”) Commission-accepted HILL \nframework uses a 50 MW threshold to evaluate reliability impacts and operational requirements \n \n28  IRR Proposal at 10-11; proposed Tariff Module A, § 1.L (Definition of “Large Load”); Li Testimony at 11-13. \n29  IRR Proposal at 10-11; Li Testimony at 12-13."},{"page":8,"startToken":1998,"endToken":2330,"text":"8 \nfor load connected above 69 kV.30  NERC’s ongoing Computational Load initiative likewise has \nconsidered registration thresholds in this range, and the current process is expressly intended to \nalign new computational-load functional entities with revisions to NERC Rules of Procedure \nAppendix 5B.31  Consistent with NERC’s recent developments, a 50 MW threshold is a reasonable \nand effective screening criterion, because it is sufficient to identify those loads whose individual \noperating characteristics warrants enhanced visibility to determine where specific requirements \nmay be appropriate to address the identifiable aggregate risks to the transmission system.  Further, \na 50 MW threshold is sufficiently material to warrant the Section 37A visibility requirements \nbecause it is consistent with NERC analysis that determined a 50 MW threshold captures the vast \nmajority of computational load entities that pose aggregate risks to the Bulk Power System.32  \nSecond, MISO’s footprint includes long transmission lines, constrained flowgates, and a \ndiverse resource mix, all of which make large, fast-changing loads particularly consequential for \nreal-time operations.  At this scale, a load’s behavior affects not only the local bus but also regional \npower flows and stability margins, making continuous visibility essential for reliable operations.  \nFurther, this threshold aligns with emerging NERC Technical Reasoning, which identifies that \nlarge, concentrated, and especially computational loads, exhibit fast-changing, electronics-driven \ncharacteristics that require elevated monitoring and disturbance-performance expectations.33  The \n \n30  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 13-21, 61, 64 (2026); SPP Tariff, pt. I, § 1, Definition of \n“HILL”. \n31  NERC, Project 2026-02 Computational Loads, Project Details (2026); NERC Aug. 19, 2026 Technical \nReasoning/Appendix 5B proposal reflecting current 50 MW threshold, available at: \nhttps://www.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-technical-\nreasoning.pdf. \n32  NERC, Proposed Computation Load Owner and Computational Load Operator, at 3. \n(https://prod.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-technical-\nreasoning.pdf)  \n33  See NERC, Appendix 5B Technical Reasoning - Proposed Computational Load Entity (August 19,2026); \navailable at: https://www.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-\ntechnical-reasoning.pdf"},{"page":9,"startToken":2330,"endToken":2702,"text":"9 \n50 MW threshold represents the point at which load behavior becomes operationally significant \nenough that MISO system operators require additional data and performance assurance to maintain \ngrid reliability.  The Commission need not require identical regional definitions, particularly where \nthe Show Cause Order expressly recognized that an appropriate Large Load definition should \nreflect the characteristics of MISO’s transmission system.34  Under section 205, the Commission \nevaluates the proposal before it to determine whether it is just and reasonable and not unduly \ndiscriminatory or preferential.35  Multiple approaches may satisfy that standard, and MISO need \nnot demonstrate that its proposed definition is the only reasonable approach or is superior to \nanother potentially just and reasonable definition.36  \nThird, a 50 MW threshold also is technically appropriate because loads of this size create \nmaterial system impacts—such as rapid demand swings, voltage and frequency disturbances, and \ndynamic interactions with power-electronic equipment, that cannot be reliably managed without \nenhanced modeling, telemetry, and forecasting.  Further, the threshold is sufficiently large to \nidentify concentrated load additions that warrant enhanced visibility and reliability treatment while \nproviding an objective and administratively clear rule.37  The IRR Proposal also provides clear and \nobjective \naggregation \ncriteria—single‑substation \nlocation, \ncommon \nor \ncoordinated \nownership/operation/control, and a 50 MW Demand threshold—which give customers advance \nnotice of when aggregation applies and allow MISO to administer the rule consistently where \n \n34  Show Cause Order at P 58 (explaining that an appropriate Large Load definition, including load size and \ninterconnection voltage thresholds, should be based on the characteristics of MISO’s transmission system). \n35  Advanced Energy Mgmt. All. v. FERC, 860 F.3d 656, 662 (D.C. Cir. 2017) (explaining that, in reviewing a \nsection 205 filing, the Commission restricts itself to evaluating the proposal before it); 16 U.S.C. § 824d(a)–(b). \n36  Cities of Bethany v. FERC, 727 F.2d 1131, 1136 (D.C. Cir. 1984) (upholding the Commission’s evaluation of \nwhether the proposed rate design was reasonable without requiring it to be superior to alternative designs); OXY \nUSA, Inc. v. FERC, 64 F.3d 679, 692 (D.C. Cir. 1995) (explaining that a methodology need not be the only \nreasonable methodology or the most accurate). \n37  Li Testimony at 12-13."},{"page":10,"startToken":2702,"endToken":2996,"text":"10 \ncommon ownership, operation, control, or coordinated load profiles create the potential for \naggregated transmission-system effects.38  Contrary to the Data Center Coalition’s concern that \naggregation is insufficiently objective, the Tariff itself supplies the relevant limiting criteria: \nsingle-substation location, common or coordinated control, and a 50 MW Demand threshold.39  \nThese criteria provide clear notice of aggregation applicability while preserving MISO’s ability to \nevaluate the system impacts and coordinated operations of coordinated facilities. These \nadministrable criteria align with system behavior because the Transmission System is primarily \nimpacted by the net electrical withdrawal at the point where the facilities connect, not the \nindividual facilities behind that point.  Standard steady-state modeling treats such facilities as an \nequivalent aggregated load, and commonly owned or coordinated facilities typically behave as a \nunified electrical entity.  The single-substation boundary provides a clear, electrically meaningful \npoint for aggregation while avoiding the inclusion of geographically dispersed and electrically \nunrelated facilities.  Even where multiple Points of Withdrawal exist, the facilities may affect \nshared substation equipment and upstream transmission facilities, resulting in a common or \ncoordinated system impact.  Thus, the Tariff’s objective criteria both preserve notice and reflect \nthe engineering reality of how aggregated demand interacts with upstream transmission \nequipment. \nFourth, no separate voltage threshold is necessary because Points of Withdrawal bound \napplicability across the Transmission System.  MISO’s Tariff definition of Transmission System \nincludes both facilities over which functional control has been transferred to MISO and certain \nfacilities over which MISO does not have functional control.40  Appendix H of MISO’s ISO \n \n38  IRR Proposal at 10-11; Li Testimony at 12-13. \n39  DCC Protest at 20-25; proposed Tariff Module A, § 1.L, Definition of “Large Load”. \n40  Tariff Module A, supra note 29; see also Tariff Module A, § 1.T, Definition of “Transmission System”."},{"page":11,"startToken":2996,"endToken":3288,"text":"11 \nagreement provides criteria governing the transfer of functional control of transmission facilities \nto MISO.41  Appendix H of the ISO Agreement provides the general criteria for these facilities as: \n(1) all networked facilities above 100 kV; and (2) All transformers whose two highest voltages \nqualify under the above voltage criteria; and (3) all substation equipment that forms the endpoints \nof the transmission lines in item 1, terminate the transformers in item 2, or provide voltage/stability \ncontrol.  The transferred facilities comprise the core of the MISO Transmission System.42  MISO’s \nTransmission System also includes certain Transmission Owner facilities where functional control \nhas not been transferred.  Therefore, MISO appropriately defines an administrable scope in the \nIRR Proposal without duplicative and potentially confusing voltage criteria. \nMISO’s proposed Large Load definition is just and reasonable. The 50 MW threshold is \ntechnically sound, regionally appropriate, operationally necessary, and administratively clear. \nCombined with measurement at Points of Withdrawal, it delivers the required visibility without \nimposing redundant voltage criteria. The Commission should approve the definition as a \nreasonable and well-supported approach to addressing the reliability concerns identified in the \nShow Cause Order. \n2. \nThe Computational Load definition appropriately targets additional \nrequirements to loads presenting distinct operational characteristics. \n \nMISO separately defines “Computational Load” as a Large Load comprised of 25 MW or \nmore of Demand from information technology equipment, such as servers, storage, and networking \nhardware.43  This definition serves an important risk-scaling function.  All Large Loads are  subject \nto the transition provisions, to basic facility data, modeling, telemetry, forecast-data, and audit \n \n41  Tariff Rate Schedule 1.  \n42  Rate Schedule 01, Art. One, § I.T (Definition of \"Transmission System\"). \n43  IRR Proposal at 11; proposed Tariff Module A, § 1.C, Definition of “Computational Load”; Li Testimony at 11."},{"page":12,"startToken":3288,"endToken":3566,"text":"12 \nrequirements, while the incremental PMU, ride-through, and ramp requirements apply to \nComputational Loads.44  \nThat distinction is supported by the record.  Computational Loads may exhibit rapid and \ncoordinated changes in demand, significant power-electronic behavior, and distinct responses to \ntransmission disturbances.45  The 25 MW computational component provides an objective measure \nof material computational content within an otherwise qualifying Large Load.  At the minimum \n50 MW Large Load threshold, 25 MW represents half of the facility’s Demand, providing \nquantitative context for the emerging NERC concept of facilities that primarily contain \ninformation-technology infrastructure.  \nThe unique and volatile power characteristics associated with Computational Load arise \ndirectly from the function of the underlying facility.  Although any individual Computational Load \nmay, in isolation, appear unlikely to cause a material impact on Transmission System reliability, \nNERC has already determined through its Compliance Registry framework that entities which \nindividually may not pose a material impact on reliability may nonetheless be required to register \nfor applicable Reliability Standards and Requirements when the class has demonstrated to have \nsuch a such an impact in aggregate.46  MISO’s use of a 25 MW threshold for identifying \nComputational Load is directional aligned with NERC’s emerging Computational Load Site \nconcept, which identifies computational facilities based on the presence of information-technology \ninfrastructure such as servers, storage, and networking hardware.  Within MISO’s 50 MW Large \nLoad applicability threshold, a 25 MW computational component provides an objective \nquantitative indicator that the facility contains material computational content and is therefore \n \n44  Proposed Tariff § 37A.I; IRR Proposal at 11-12, 22-26. \n45  IRR Proposal at 11-12; Li Testimony at 13-14. \n46  NERC Registry Criteria Revision 5.2, Notes to Criteria, note 1 (footnote excluded)."},{"page":13,"startToken":3566,"endToken":3830,"text":"13 \nlikely to exhibit the characteristic behaviors of computational loads—rapid and coordinated \ndemand changes, software-driven control actions, and power-electronic responses to disturbances.  \nThis objective threshold enables MISO to proactively apply targeted PMU, ramp-rate, and \nride-through requirements where the electrical behavior associated with computational activity is \npredictably present, rather than waiting for those behaviors to manifest in operations, which could \nexpose the system to unmitigated reliability risks. \nGoogle argues that reliability requirements should turn exclusively on electrical \ncharacteristics rather than end use, and DCC similarly seeks narrower and more predictable \nclassification criteria.47  MISO agrees with the underlying principle that requirements should \ncorrespond to reliability risk; which is precisely why the IRR Proposal does not impose the \nincremental PMU, ramp, and ride-through requirements on every Large Load.48  The \nComputational Load definition is a reasonable proxy for the set of facilities currently known to \npresent the rapid, coordinated, power-electronic behavior that motivated those requirements, and \nthe Tariff authorizes MISO to determine whether Computational Load is associated with a Large \nLoad based on information supplied by the Transmission Customer.49  MISO can refine \nimplementation as operating experience and NERC standards develop without delaying \nprotections that the record demonstrates are needed now.50  \nB. \nTHE TRANSITION PROVISIONS REASONABLY PROTECTS EXISTING COMMERCIAL \nARRANGEMENTS  WITHOUT SACRIFICING RELIABILITY. \n \n1. \nThe transition framework directly responds to the Show Cause Order \nand uses objective Tariff milestones. \n \n \n47  Google Comments at 5-8; DCC Protest at 20-25. \n48  IRR Proposal at 11-12; Li Testimony at 13-14. \n49  Proposed Tariff § 37A.I. \n50  IRR Proposal at 2-4, 7-9; NERC et al. Comments at 6-9."},{"page":14,"startToken":3830,"endToken":4112,"text":"14 \nMISO’s transition framework responds to the Show Cause Order by using objective Tariff \nmilestones to accommodate existing commercial arrangements and agreements nearing \ncompletion.  The Commission directed MISO to provide a reasonable implementation period that \nminimizes disruption to existing commercial arrangements, allows reasonable time to finalize \nongoing agreements nearing completion when the Tariff provisions are filed, and establishes an \neffective date that accommodates those considerations.51  Paragraph 36 of the Show Cause Order \nfurther calls for a reasoned explanation of how the proposal will avoid disrupting existing \ncommercial arrangements and an identification of a reasonable effective date that accommodates \nthose arrangements.52  MISO’s framework addresses those objectives through differentiated \ntreatment based on Service Commencement Date and the MTEP/EPR Condition, rather than \nrequiring MISO to assess individual private contracts.53 \nFirst, a Large Load with a Service Commencement Date on or before December 4, 2026 is \nexempt from Section 37A with respect to the portion of the Large Load that has procured \nTransmission Service as of its Service Commencement Date.54  That exemption does not \nautomatically extend to subsequent increases in Transmission Service. A modification or series of \nmodifications resulting in a cumulative increase of 25 MW or more, with a Service \nCommencement Date after December 4, 2026, may subject the additional Load to Section 37A’s \nrequirements, depending on whether the additional Load satisfies the applicable MTEP/EPR \nCondition and other transition criteria.55  The framework therefore distinguishes the previously \n \n51  Show Cause Order at P 5; IRR Filing at 13. \n52  Show Cause Order at P 36.  \n53  IRR Proposal at 13-15; Li Testimony at 23-27; proposed Tariff  \n54  Proposed Tariff § 37A.II.2(a); IRR Proposal at 14-15. \n55  Id."},{"page":15,"startToken":4112,"endToken":4377,"text":"15 \nexempt portion of the Large Load from additional Load commencing service after the effective \ndate; the requirements applicable to that additional Load are determined under the Tariff’s \ntransition provisions.56 \nSecond, a Large Load, or portion thereof, that has not commenced service by the effective \ndate but satisfies the MTEP/EPR Condition remains subject to visibility requirements while \nreceiving an exemption from ramp and ride-through requirements.57  Third, a Large Load, or \nportion thereof, that does not qualify for those exemptions but is associated with a transmission \nproject submitted for EPR after June 18, 2026 and on or before October 31, 2026 is generally \nsubject to all applicable requirements, but MISO may, however, waive the ride-through \nrequirements where an exemption would not adversely affect reliability and compliance would \nimpose significant costs.58  Large Loads and additional load outside specified transition categories \nare subject to all applicable requirements.59  \nThese provisions account for both commercial reliance and the costs of implementing new \nrequirements.  The exemptions from ramp and ride-through requirements limit the potential need \nto revisit equipment selections and operating arrangements made in reliance on existing \nrequirements, while the visibility requirements applicable to Load satisfying the MTEP/EPR \nCondition provide MISO with information needed to assess and manage reliability.  The limited \nride-through waiver expressly addresses circumstances in which compliance would impose \nsignificant costs, but conditions relief on a determination that the exemption would not adversely \n \n56  Id. \n57  Proposed Tariff § 37A.II.2(b); IRR Proposal at 14-15.  \n58  IRR Proposal at 14-15; proposed Tariff § 37A.II.2(b)-(c). \n59  IRR Proposal at 15."},{"page":16,"startToken":4377,"endToken":4657,"text":"16 \naffect reliability.60  Significant costs alone therefore do not establish entitlement to a waiver.  This \napproach accommodates existing commercial arrangements while preserving a reliability \nassessment for the additional relief available under the waiver provision. \nThese milestones are preferable to a project-by-project inquiry into private commercial \ncommitments.  DCC and Rowan propose transition protection based on executed agreements, \nequipment orders, investments, or other project-maturity evidence.61 Such an approach is \nunworkable for MISO.  Treating all agreements as a sufficient determination of project maturity \nwould render the requirement largely meaningless, as such agreements may not indicate actual \ncommitment.  Likewise, developing prescribed contractual terms and requirements would be \nunworkable for Large Loads whose commercial arrangements do not conform to predefined \nstructures.  In the alternative, requiring MISO to make an individualized determination for each \npiece of evidence would require a degree of specialized legal knowledge and commercial expertise \nthat MISO does not possess and could not reasonably acquire without significant staff \naugmentation.  Even with additional staff, applying individualized determinations across a \ngeographical footprint that spans 15 states will almost inevitably involve discretionary judgements \nand lead to substantial disputes.  Those considerations may be relevant to a developer’s private \neconomics, but they are not uniform milestones that can reasonably be administered by MISO \nunder its Tariff.  Using private contracts would require MISO to evaluate agreements entered into \nand commercial commitments made outside of MISO’s Tariff framework to determine whether \neach project is sufficiently mature, introducing variability, disputes, and inconsistent treatment.62  \nBy contrast, Service Commencement Date, MTEP approval, and EPR submission are objective \n \n60  Proposed Tariff § 37A.II; IRR Filing at 14-15. \n61  DCC Protest at 25-29; Rowan Protest at 3. \n62  IRR Proposal at 13-14."},{"page":17,"startToken":4657,"endToken":4910,"text":"17 \nmilestones within MISO’s own processes and are readily verifiable and consistently \nadministered.63  \n2. \nThe transition provisions are narrowly tailored and preserve MISO’s \nauthority to address material adverse reliability impacts while \naccommodating existing commercial arrangements. \n \nMISO’s transition provisions operate within an existing framework of reliability \nassessments and local planning and interconnection requirements.  MISO’s Transmission Owners \nalready evaluate load additions through their planning and interconnection processes; ATC, for \nexample, maintains documented local planning and load-interconnection procedures.64  Section \n37A’s ramp and ride-through requirements complement these existing practices by establishing \nconsistent minimum performance expectations for Computational Loads across the MISO \nfootprint. \nMISO’s transition framework provides three forms of relief.  First, qualifying Large Loads \nwith a Service Commencement Date on or before December 4, 2026, are exempt from Section \n37A with respect to the portion of the Load that has procured Transmission Service as of that date.  \nSecond, qualifying Large Loads meeting the MTEP/EPR Condition remain subject to the \napplicable visibility and PMU requirements but are exempt from the ramp and ride-through \nrequirements.  Third, eligible EPR submissions made between June 19 and October 31, 2026, \nremain subject to all applicable requirements, except that MISO may waive ride-through \nrequirements upon determining that the exemption would not have an adverse reliability impact \nand compliance would result in significant costs.65  This framework thus balances the \n \n63  IRR Proposal at 13-15; Li Testimony at 23-27. \n64  Show Cause Order at P 28 & nn.74-75. \n65  Proposed Tariff § 37A.II; IRR Proposal at 14; Li Testimony at 19022."},{"page":18,"startToken":4910,"endToken":5189,"text":"18 \nCommission’s express concern of limiting impacts to existing and near-complete commercial \narrangements with the need to preserve reliability.66 \nOMS, the PIOs, and the Joint Consumer Advocates raise concerns that the transition \nprovisions could exempt a substantial quantity of existing or planned Large Load from some \nrequirements.67  But the quantity of transitioned load does not establish that the transition \nframework is unjust and unreasonable.  The relevant question is how the differentiated transition \nprovisions operate alongside existing reliability protections, retained information requirements, \nand MISO’s continuing authority to address reliability impacts. \nThe partial exemptions do not eliminate the information requirements that enable MISO to \nevaluate reliability risks.  Large Loads qualifying for partial exemptions remain subject to basic \nfacility data, modeling, telemetry, forecasting, and audit requirements, as well as PMU \nrequirements where applicable, under the prescribed compliance timelines.68  These baseline \nrequirements provide the real-time and planning-stage information necessary to support \ncontingency analysis, operational assessments, and the evaluation of disturbance performance, \nthereby maintaining system awareness even for partially exempt facilities.  In particular, the \nmodeling provisions require verified models reflecting actual facility characteristics and \ncontinuing updates, while the forecasting provisions require current information supporting \ncommitment and dispatch.69  The IRR framework complements MISO’s existing planning, \ninterconnection, and operational processes, which continue to govern reliability evaluations and \nensure that Large Loads are incorporated into model verification, forecasting, and operational \n \n66  Show Cause Order at P 5; IRR Proposal at 13–14. \n67  OMS Comments at 4-5; PIO Protest at 1-7; Joint Consumer Advocates Protest at 2-4. \n68  Proposed Tariff § 37A.II.2(b); id. §§ 37A.1–37A.5, 37A.8. \n69  Proposed Tariff §§ 37A.2, 37A.4; Li Testimony at 26:9-14."},{"page":19,"startToken":5189,"endToken":5483,"text":"19 \ndecision-making.  Although qualifying fully exempt loads receive broader relief, the transition \nframework does not categorically exempt developing Large Loads from the visibility requirements \nneeded to assess their reliability impacts. \nThe transition provisions also do not create an absolute or perpetual reliability exemption.  \nSection 37A expressly provides that, notwithstanding the transition provisions, MISO may require \ncompliance with any or all Section 37A requirements if MISO determines that operation of a Large \nLoad results in a material adverse effect on Transmission System reliability.70  Available models, \nplanning assessments, operating data, and disturbance information can inform that determination \nand the identification of requirements needed to address the impact.  The process for making that \ndetermination and identifying which requirements must apply will be set forth in the Large Load \nBPM.71  This targeted reliability backstop preserves commercial certainty while allowing MISO \nto apply otherwise-exempt requirements where the Tariff’s reliability criterion is met.72 \nTo the extent a party contends that the Tariff permits a Large Load to create reliability \nconcerns while constraining MISO’s ability to act, MISO respectfully clarifies that the transition \nprovisions do not limit, displace existing reliability obligations, or restrict MISO’s responsibilities \nas Reliability Coordinator.  IRO-001-4 requires MISO to address reliability within its Reliability \nCoordinator Area through direct action or Operating Instructions, and requires specified entities to \ncomply with those instructions subject to the standard’s stated exceptions.73  Those obligations \napply independently of a Large Load’s transition status.  Accordingly, the PIOs’ concern that \nMISO’s hands would be tied until a Large Load causes a reliability problem conflates the specific \n \n70  Proposed Tariff § 37A.II.3. \n71  Id.  \n72  IRR Proposal at 13–14; Li Testimony at 23:1–5; Proposed Tariff § 37A.II.3. \n73  NERC Reliability Standard IRO-001-4, “Reliability Coordination—Responsibilities,” Requirements R1–R3."},{"page":20,"startToken":5483,"endToken":5752,"text":"20 \ntrigger for imposing otherwise-exempt Section 37A requirements with MISO’s continuing \noperational reliability responsibilities.  The transition provisions do not require MISO to await \nactual harm before exercising its existing reliability authority. \nFinally, the IRR Proposal proceeds alongside NERC’s ongoing work to develop \nComputational Load Reliability Standards and related registration criteria.74  That work provides \na further opportunity for alignment as industry requirements evolve; it does not justify delaying \nthe near-term protections proposed here.  Together, existing local requirements, retained visibility \nobligations for partially exempt loads, the targeted Section 37A backstop, and MISO’s continuing \nReliability Coordinator responsibilities preserve reliability while accommodating the commercial \narrangements identified by the Commission. \n3. \nThe cost-shifting arguments do not justify rejection or modification of \nthe IRR transition provisions. \n \nThe PIOs and Joint Consumer Advocates contend that exempting some Large Loads from \nfacility-side requirements could lead to system mitigation costs that are borne by other \ncustomers.75  Those assertions do not establish a defect in this filing.  The IRR Proposal is directed \nto operational reliability requirements applicable to Large Load facilities and Transmission \nCustomers; it does not purport to resolve the distinct questions of transmission-service design, \nstudy processes, or cost allocation identified in the Show Cause Order.76  \nMISO is separately developing proposals to address potential cost shifts associated with \nLarge Load additions, along with additional transmission service products and enhanced Large \nLoad application and study processes, for filing in connection with the Commission’s November \n \n74  NERC, Project 2026-02—Computational Loads; IRR Proposal at 3. \n75  PIO Protest at 3-7; Joint Consumer Advocates Protest at 3-4. \n76  IRR Proposal at 1, 4, 9; Li Testimony at 9-11."},{"page":21,"startToken":5752,"endToken":6030,"text":"21 \n16, 2026 deadline.77  The Commission should evaluate those cost-allocation issues on the record \ndeveloped for those proposals rather than use speculative future cost outcomes to reject transition \nprovisions that address a different and immediate reliability need.78  \n4. \nRowan’s requested transition and review clarifications do not require \nrejection of the filing. \n \nRowan requests additional specificity concerning project-maturity evidence, waiver \ndocumentation, review timelines, “material modifications,” and written decision criteria.79  Many \nof these requests concern implementation procedures that MISO is continuing to develop through \nthe Large Load Working Group (“LLWG”) and the Large Load BPM.80  MISO notes it is \ncontinuing to work with collaboratively stakeholders through the LLWG and has posted draft BPM \nlanguage for stakeholder review and feedback.81  \nC. \nTHE IRR PROPOSAL PROPERLY PLACES CORE REQUIREMENTS IN THE TARIFF \nAND IMPLEMENTATION DETAIL IN THE BPMS. \n \n1. \nThe Tariff contains the operative obligations and satisfies the \nCommission’s Rule of Reason. \n \nEntergy, the Southern Regulators, DCC, the PIOs, Google, and certain Large Energy Users \nargue in varying degrees that more technical detail should be placed in the Tariff rather than the \nBPMs.82  The Commission’s rule of reason requires tariff filing of provisions that significantly \naffect rates, terms, and conditions of service, are readily susceptible of specification, and are not \n \n77  IRR Proposal at 4. \n78  IRR Proposal at 1, 4. \n79  Rowan Protest at 1-3. \n80  IRR Proposal at 28-30; Li Testimony at 36-40. \n81  LLWG BPM feedback response, tag Oct 8 meeting materials and feedback request.  \n82  Entergy Protest at 4-17; Southern Regulators Protest at 1-2; DCC Protest at 6-15; PIO Protest at 19-23; Google \nComments at 7-8; Large Energy Users Protest at 7-9."},{"page":22,"startToken":6030,"endToken":6352,"text":"22 \ngenerally understood in a contractual arrangement.83  It does not require every engineering \nparameter, data format, testing protocol, or implementation procedure to be frozen in a filed \ntariff.84  The Tariff appropriately balances the core details and principled requirements required \nfor clarity within the tariff and the need for flexibility to address technical and administrative \ndetails that can mature in this particularly evolving area. \nSection 37A contains the core obligations.  It identifies who is responsible for compliance; \nwhich requirements apply to all Large Loads and which apply only to Computational Loads; the \ncategories of required facility information and modeling; the obligation to provide real-time \ntelemetry; the requirement to provide forecast data; the location and ownership framework for \nPMU equipment; the obligation of Computational Loads to ride through specified disturbances; \nthe measurement framework for ramp limits, including aggregate measurement at applicable \nPoints of Withdrawal and eligibility for ramp smoothing; audit rights; transition categories; and \nconsequences that may follow noncompliance.85  Those are the terms that establish the parties’ \nsubstantive rights and obligations. \nThe BPMs then provide the technical and administrative detail needed to implement those \nfiled obligations consistently, including formats, timelines, technical performance curves, \nmeasurement intervals, validation protocols, communications specifications, and processes for \ndetermining remediation.86  That division is both practical and necessary in a rapidly evolving \n \n83  Midcontinent Indep. Sys. Operator, Inc., 169 FERC ¶ 61,221, at P 67 2019, citing Energy Storage Ass’n v. PJM \nInterconnection, L.L.C., 162 FERC ¶ 61,296, at P 103 2018; City of Cleveland v. FERC, 773 F.2d 1368, 1376 \nD.C. Cir. 1985. \n84  See Midcontinent Indep. Sys. Operator, Inc., 170 FERC ¶ 61,075, at P 38, 2020 (accepting use of BPM detail \nwhere tariff contained governing requirements and noting that tariff codification could curb needed operational \nflexibility.). \n85  Proposed Tariff §§ 37A.I, 37A.1-37A.8, 37A.II; IRR Filing at 22-27. \n86  IRR Proposal at 19-21, 23-27; Li Testimony at 28-35."},{"page":23,"startToken":6352,"endToken":6592,"text":"23 \ntechnical area where MISO, NERC, equipment manufacturers, Transmission Owners, and \nTransmission Customers taking Transmission Service on behalf of Large Loads are continuing to \ngain operating experience.87  \nAs industry gains experience with Large Loads, emerging usage patterns may provide \ninsight into forecasting.  Ramp-rate limits are designed to ensure that changes in Large Load net \ndemand do not pose unacceptable risk to the reliable operation of the transmission system.  \nTechnological advancements such as improved telemetry or enhanced forecasting may increase \nthe maximum ramp-rate that the transmission system can reliably accommodate.  Because Large \nLoads rely on fast-acting controls, power-electronic interfaces, and increasingly sophisticated \nuninterruptible power supply systems, the detailed technical parameters that govern telemetry, \nPMU configuration, forecasting formats, ride-through curves, testing protocols, and ramp-rate \nmeasurement must remain adaptable as equipment capabilities evolve, NERC’s Computational \nLoad Owner (CLO) standards finalize, and MISO gains operational experience with real-world \nLarge Load behavior.  While the Tariff sets the binding reliability obligations, the technical \nimplementation must evolve over time, and MISO expects continued refinement in areas such as \ntelemetry resolution and data exchange methods, PMU placement and measurement settings, \nforecasting cadences, disturbance-performance envelopes, and ramp-measurement windows to \nensure alignment with equipment capabilities, emerging NERC standards, and observed operating \nbehavior. \n2. \nThe Commission’s acceptance of SPP’s HILL framework confirms \nthat a tariff may establish core Large Load obligations while leaving \nimplementation detail outside the tariff. \n \n \n87  IRR Proposal at 2-4, 28-30; NERC et al. Comments at 6-9."},{"page":24,"startToken":6592,"endToken":6892,"text":"24 \nThe Commission recently accepted SPP’s HILL framework, which established enhanced \nstudy and ongoing operational requirements for high-impact loads, including nonconforming-load \nforecasting, real-time telemetry, remote-disconnect capability, a ramp-rate limit, installation of a \nPMU or similar equipment, and ride-through guidelines.88  The Commission did not require SPP’s \ntariff to reproduce every technical specification associated with each operational requirement; \nrather, the Commission accepted SPP’s ongoing operational requirements whose guidelines were \nset forth in a separate, non-tariff document.89  The relevant comparison therefore supports, rather \nthan undermines, MISO’s approach: the Tariff must state the operative obligation and sufficiently \nconstrain discretion, while technical implementation can be developed in manuals and guidelines. \nMISO’s proposed Tariff is clear on the fundamental categories of ongoing operational \nrequirements identified by the Show Cause Order.  For example, Section 37A.7 states that \nComputational Load is subject to up- and down-ramp limits during stable-state transitions, \nmeasured in aggregate across applicable Points of Withdrawal, permits eligible generation or other \nresources to provide ramp smoothing, and provides for MISO to establish limits consistent with \nthe BPM process.90  MISO has proposed initial up- and down-ramp limits of 30 MW/minute in its \ntechnical materials.91  Similarly, Section 37A.6 requires Computational Load to remain connected \nand continue operation during voltage and frequency disturbances within performance criteria \nestablished through the BPM, with compliance evaluated at the Points of Withdrawal.92  \n \n88  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 13-21, 61, 63 (2026); Midcontinent Indep. Sys. Operator, Inc., \n195 FERC ¶ 61,212, at PP 22-23 & nn. 58-59 (2026). \n89  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 20-21, 63 (2026). \n90  Proposed Tariff § 37A.7; IRR Proposal at 20, 26. \n91  IRR Proposal at 20; Li Testimony at 30-32. \n92  Proposed Tariff § 37A.6; IRR Proposal at 20-21, 25-26."},{"page":25,"startToken":6892,"endToken":7134,"text":"25 \nMISO's initial ±30 MW/minute ramp limit establishes a reasonable, industry-informed \nbaseline for managing rapid demand changes from Computational Loads.  The limit is intended to \nreduce sudden balancing needs and significant changes in transmission flows during stable-state \ntransitions, while providing a consistent and predictable operating expectation.  This initial limit \nis informed by comparable industry practices and may be refined as MISO gains additional \noperating experience and develops more detailed technical criteria.  Because the Transmission \nSystem experiences the aggregate net demand at the applicable Points of Withdrawal (POWs), the \nramp requirement is measured across those interfaces rather than individual computational \nequipment or load components.  This approach captures the actual impact on the Transmission \nSystem and provides flexibility for eligible associated generation, energy storage, uninterruptible \npower supply systems, and other load-management technologies to smooth demand changes, \nprovided the resulting net ramp complies with applicable requirements.  The ride-through \nframework addresses a separate but complementary reliability concern by establishing minimum \nvoltage and frequency performance expectations during system disturbances.  Applying these \nrequirements with reference to the POWs supports predictable aggregate load response, reduces \nthe risk of unnecessary simultaneous disconnections, and promotes stable post-disturbance \nrecovery. \n3. \nMISO’s transparent stakeholder process provides additional \nprotection against arbitrary implementation and supports continued BPM \ndevelopment. \n \nThe premise that MISO will develop the BPM requirements without meaningful \nstakeholder input is inconsistent with the record.  MISO began discussing Large Load reliability \nrequirements with stakeholders early in 2026 and repeatedly revised both Tariff and"},{"page":26,"startToken":7134,"endToken":7392,"text":"26 \nimplementation concepts in response to feedback.93  At the April 20 LLWG and April 22 Planning \nAdvisory Committee (“PAC”) meetings, MISO presented revised definitions and transition \nconcepts; at the May 14 LLWG it provided proposed Tariff language and further revisions; at the \nJune 10 LLWG it revised applicability, transition provisions, roles and responsibilities, and \nrequirement-specific language based on stakeholder feedback; and at the June 29, July 16, July 27, \nand August 12 LLWG meetings it continued refining the Tariff, Technical Compendium, and \nLarge Load BPM framework.94  \nThat process is continuing.  MISO has proposed a “hub-and-spoke” BPM architecture with \na Large Load BPM serving as the central implementation manual and coordinated revisions to \nexisting BPMs.95  MISO has separately solicited stakeholder feedback on operational forecasting, \ntelemetry and PMU requirements, ride-through, ramping, and related BPM provisions.96  This \ntransparent process allows technical requirements to be refined as systems and industry standards \nevolve without repeatedly reopening the Tariff for every implementation adjustment. \nD. \nMISCELLANEOUS COMMENTS AND PROTESTS. \n \n1. \nThe IRR requirements apply to Transmission Customers taking \nTransmission Service on behalf of Large Loads connected to the MISO \nTransmission System. \n \nThe Midwest TDUs request confirmation that Section 37A does not independently extend \nto loads interconnected only to a distribution system and that compliance obligations will not \n \n93  Li Testimony at 35-40; IRR Proposal at 28-30. \n94  Li Testimony at 35-40 & Attachment A. \n95  Li Testimony at 38-39. \n96  Large Load Working Group: Large Load Operational Forecast Requirements; Stakeholder feedback, available \nat: https://www.misoenergy.org/engage/stakeholder-feedback/2026/llwg-large-load-operational-forecast-\nrequirements-llwg-2026-4a-20260827/."},{"page":27,"startToken":7392,"endToken":7688,"text":"27 \nunduly burden Transmission Customers.97  The Tariff already answers the first question.  In MISO, \nthe Transmission System is used to provide Transmission Service, while the Wholesale \nDistribution System transmits energy over Distribution Facilities.98  Section 37A applies to a \n“Transmission Customer taking Transmission Service on behalf of a Large Load,” and the Large \nLoad definition itself is framed by Points of Withdrawal “from the Transmission System.”99  Thus, \nthe IRR Proposal does not create a free-standing MISO reliability regime for distribution-\nconnected load that is not taking MISO Transmission Service.100  \n2. \nThe Tariff reasonably assigns compliance responsibility to the \nTransmission Customer while permitting contractual arrangements and \nother documentation to demonstrate the ability to effectuate compliance. \n \nThe Midwest TDUs and Rowan emphasize that the Large Load customer or equipment \nowner may control information or equipment needed for compliance.101  MISO recognizes that \npractical reality, but MISO generally lacks contractual privity with the Large Load itself.  The \nTransmission Customer, by contrast, takes Transmission Service under a service agreement \nincorporating the Tariff and therefore provides the legally enforceable relationship through which \nSection 37A can operate.102  This approach is also consistent with the Show Cause Order’s focus \non obligations of the Eligible Customer or transmission customer taking service on behalf of the \nLarge Load.103  \n \n97  Midwest TDUs Comments at 1-2, 9-16. \n98  Tariff Module A, § 1.T (Definition of “Transmission Service”); id. § 1.W (Definition of “Wholesale \nDistribution Service”). \n99  Proposed Tariff § 37A.I; proposed Tariff Module A, §§ 1.L and 1.P (Definitions of “Large Load” and “Points of \nWithdrawal”). \n100  IRR Proposal at 12; Li Testimony at 14-16. \n101  Midwest TDUs Comments at 10-14; Rowan Protest at 1-2. \n102  IRR Proposal at 12-13; Li Testimony at 14-16. \n103  Show Cause Order at P 64."},{"page":28,"startToken":7688,"endToken":7958,"text":"28 \nThe proposed Tariff expressly accommodates contractual arrangements between the \nTransmission Customer and the Large Load.  A Transmission Customer must demonstrate its \nability to effectuate compliance and provide documentation necessary for MISO to verify \ncompliance; that documentation “may include applicable agreements, if any,” between the \nTransmission Customer and the entities that own, operate, or use the Large Load, or an officer \nattestation demonstrating access to the information needed for compliance.104  Thus, an agreement \nassigning relevant performance and information duties to the Large Load may be part of a \nsufficient compliance showing, although MISO must retain authority to evaluate whether the \ndocumentation actually enables the Transmission Customer to meet the Tariff obligation.105 \nIn order to ensure reliability MISO must be able to perform the Reliability Assessment \nCommitment (“RAC”) and Security Constrained Economic Dispatch (“SCED”) studies, among \nothers.  Because the RAC ensures power is available to the grid, it requires inputs of forecasted \ndemand, and because the SCED balances power injections with withdrawals, it requires inputs of \nramp-rates, load forecasts, and current state estimation (telemetry). \nMISO will require load forecasts sufficient for RAC, SCED, and other reliability studies.  \nIn order to ensure system reliability and facilitate RAC and SCED, MISO needs telemetry, \nmetering, and PMU data.  In order to study operating characteristics proactively MISO needs EMT \nmodel data and other equipment level model data, including protection settings, ride-through \nbehavior, dynamic characteristics, staged development plans, and other operational attributes that \nare identified to materially affect reliability.  MISO would also require sufficient information to \nvalidate compliance with registration, modeling, and forecasting obligations, including the right \n \n104  Proposed Tariff § 37A.I. \n105  Id."},{"page":29,"startToken":7958,"endToken":8197,"text":"29 \nto audit or verify any information submitted.  MISO must be able to obtain, through the \nTransmission Customer, all information and operational access necessary to evaluate, monitor, and \nverify Large Load behavior under Section 37A, including the facility data, electrical models, \ntelemetry, PMU measurements, and forecasting inputs required to support planning studies, \noperational assessments, and disturbance-performance evaluations.  Because the Tariff designates \nthe Transmission Customer as the responsible party, the Transmission Customer is required to \n“demonstrate its ability to effectuate compliance” and to provide the documentation MISO needs \nto verify adherence to Section 37A, with that documentation expressly permitted to include \nagreements or officer attestations establishing the Transmission Customer’s access to the \ninformation needed for compliance.  This structure ensures that MISO can obtain the visibility, \nmodeling inputs, and operational coordination needed to implement the reliability requirements \neven when the end-use Large Load owns or controls specific equipment. \nSection 37A also identifies the potential consequences of noncompliance: delayed Service \nCommencement Date, time for corrective action, operational limitations, or other remediation \nnecessary to maintain Transmission System reliability, with the process for determining \nappropriate measures set forth in the BPM.106  These are reliability remedies, not an automatic \npenalty schedule.  MISO will continue working with Transmission Customers and Large Loads \nthrough implementation to facilitate efficient compliance and provide education regarding the new \nrequirements. \n3. \nThe operational forecasting requirements are needed for reliability \nand should apply to Large Loads. \n \n \n106  Proposed Tariff § 37A.I."},{"page":30,"startToken":8197,"endToken":8481,"text":"30 \nThe Large Energy Users object in particular to a five-minute real-time forecasting \nrequirement for non-computational Large Loads and argue that the requirement could impose costs \non traditional industrial customers.107  Forecasting is a visibility requirement, not a computational-\nload-specific performance requirement.  The Commission itself identified the absence of hourly \nforecasts and other visibility data as a potential Tariff deficiency.108  MISO’s record likewise \nexplains that accurate forecasting is necessary to anticipate Large Load Demand and operating \nchanges, support commitment and dispatch, and manage variability in the operational horizon.109  \nShort-term operational forecasts are needed because Large Loads can change system \nconditions rapidly and cannot be forecast accurately using traditional, weather- and calendar-based \nmodels, making timely visibility into expected demand essential for reliable RAC, SCED, and \nother operational studies.  As Ms. Li explains, day-ahead and real-time forecasts provide MISO \nwith the information needed to anticipate demand changes and maintain reliable commitment and \ndispatch, and that forecasts must be updated to reflect the most current expected conditions.110  \nAlthough MISO’s forecasting processes operate on hourly and five-minute horizons, the \nrequirement concerns forecast visibility, not an obligation for the customer to follow a five-minute \nschedule; it ensures MISO has sufficiently granular insight into facilities whose deviations may be \noperationally material.  Section 37A establishes the obligation to provide this information while \nimplementation details, such as cadence, formats, and processes, are appropriately refined through \nthe BPM, allowing MISO to tailor burden and accommodate practical considerations while \npreserving the reliability objective of accurate short-term forecasting. \n \n107  Large Energy Users Protest at 5-9. \n108  Show Cause Order at P 64; IRR Proposal at 6. \n109  IRR Proposal at 3, 8-9, 17-18; Li Testimony at 18-20. \n110  Li Testimony at 26."},{"page":31,"startToken":8481,"endToken":8763,"text":"31 \nMISO’s stakeholder materials have proposed short-term forecast submissions at the \nCommercial Pricing Node (“CPNode”) level on hourly and five-minute cadences aligned with \ncommitment and dispatch.111  The purpose of the five-minute data is not to presume that every \nindustrial load behaves like a data center; it is to provide MISO sufficient near-term visibility into \na 50 MW-or-larger facility whose deviations can be operationally material and impact \nTransmission System reliability.112  MISO is continuing to work with stakeholders on forecast \nhorizons, submission mechanics, validation, tolerance bands, and any incentive framework, which \nare precisely the kinds of implementation details appropriately addressed through the BPM \nprocess.113  \nMISO expects to use hourly forecasts as inputs to reliability commitment processes, \nincluding Multi-Day, Next-Day and Intraday RACs.  MISO expects to use five-minute forecasts \nas inputs to the Look-Ahead Commitment and UDS.  Both forecasts are required at the CPNode \nlevel to facilitate accurate integration of data submission into the network model for congestion \nand contingency analysis.  Large Loads can change system conditions rapidly in ways that cannot \nbe reliably predicted from historical, weather-based, or calendar-based forecasting methods, which \ncreates a reliability need for timely and accurate short-term operational forecasts.  Day-ahead and \nreal-time forecast submissions give operators essential forward visibility into expected demand \nand enable informed commitment, dispatch, and other real-time reliability studies such as RAC \nand SCED.  Accurate short-term forecasts support situational awareness by allowing operators to \nanticipate material changes in consumption, assess the need for balancing actions, and identify \n \n111  Li Testimony at 38; MISO, Large Load Operational Forecast Requirements, LLWG on Aug. 27, 2026. \n112  Li Testimony at 8. \n113  MISO Large Load Operational Forecast Requirements Stakeholder Feedback Sessions held from August through \nSeptember, 2026."},{"page":32,"startToken":8763,"endToken":9014,"text":"32 \nconditions that may produce contingency risks.  The value of granular, frequently updated \ninformation lies in improving MISO’s ability to understand and respond to changes in Large Load \nbehavior, not in imposing a requirement that customers follow a five-minute dispatch schedule.  \nBecause the Tariff sets only the obligation to provide timely and updated forecasts, implementation \ndetails, including the cadence, format, and level of granularity, have been developed through the \nBPM.  \nE. \nCONCLUDING ARGUMENTS \nThe IRR Proposal should be accepted as filed.  It responds directly to the Commission’s \nidentified operational-reliability concerns, establishes enforceable Tariff obligations for visibility, \nPMUs, ramping, and ride-through, scales incremental requirements to Computational Loads, and \nprovides a reasonable transition framework for existing and in-flight projects.114  The comments \nidentify implementation questions that MISO is actively addressing through the LLWG and BPM \nprocess, but they do not demonstrate that the filed framework is unjust or unreasonable. \nIn addition, the Commission should not delay acceptance of this filing until every related \nLarge Load issue is resolved.  MISO expressly identified that transmission-service products, \nenhanced study processes, and cost-shifting protections would be addressed through separate \nproposals, and MISO continues to develop those proposals in advance of the Commission’s \nNovember 16, 2026 deadline.115  The immediate operational needs addressed here—that is, \nvisibility, forecasting, monitoring, ramping, and disturbance performance—exist regardless of the \nfinal design of those later proposals.116  \n \n114  IRR Proposal at 1-4, 9-27; Show Cause Order at P 64. \n115  IRR Proposal at 1, 4. \n116  IRR Proposal at 2-4, 7-9."},{"page":33,"startToken":9014,"endToken":9258,"text":"33 \nFinally, continued use of BPMs for technical implementation is a feature of the framework, \nnot a defect.  Large Load technologies, NERC standards, and MISO’s own operating experience \nare developing quickly.  The Tariff establishes the enforceable substantive obligations, while the \nBPMs allow MISO, Transmission Owners, customers, and stakeholders to refine technical \nimplementation in a transparent process as experience grows.117  That structure provides the \ncombination of certainty and flexibility necessary to integrate Large Loads reliably and efficiently. \nRetaining detailed technical implementation in the BPM and Technical Compendium is \nimportant because the Tariff establishes the core Section 37A obligations, while the underlying \nreliability needs continue to evolve with new NERC guidance, emerging Large Load technologies, \nand growing operating experience.  NERC’s work on emerging large loads highlights the need for \nongoing refinement of modeling practices, real-time telemetry and PMU measurement \ncapabilities, \nshort-term \nforecasting \nmethods, \nramp-rate \ncharacterization, \nand \ndisturbance-performance expectations as equipment designs and dynamic behaviors change over \ntime.  As a result, technical parameters such as the model detail required to represent \npower-electronic controls, the resolution and configuration of telemetry and PMU data, \nassumptions used in near-term forecasting, and active-power recovery behavior during \ndisturbances are expected to require periodic updates.  Housing these specifics in the BPM and \nTechnical Compendium allows MISO to incorporate new standards, device capabilities, and \noperating insights without altering the fundamental reliability requirements set forth in \nSection 37A. \n \n117  IRR Proposal at 19-21, 23-30; Li Testimony at 28-40; NERC et al. Comments at 6-9."},{"page":34,"startToken":9258,"endToken":9436,"text":"34 \nIV. \nNOTICE AND SERVICE \nMISO has served a copy of this filing electronically, including attachments, upon each \nperson designated on the official service list compiled by the Secretary as well as on all Tariff \ncustomers, MISO Members, Member representatives of transmission owners and non-\ntransmission owners, as well as all state commissions within the MISO Region and the \nOrganization of MISO States.  The filing has been posted electronically on MISO’s website at \nhttps://www.misoenergy.org/legal/ferc-filings/ for other interested parties in this matter. \nV. \nCONCLUSION  \nMISO respectfully requests that the Commission (i) accept this Answer and (ii) accept the \nIRR Proposal without modification or condition.  \nRespectfully submitted,  \n/s/ Kalen Coleman \nMichael Kessler  \nManaging Assistant General Counsel \nKalen Coleman \nCorporate Counsel \nMidcontinent Independent System \nOperator Inc.  \n720 City Center Drive \nCarmel, Indiana 46032 \nTelephone: 317 249-5400 \nmkessler@misoenergy.org \nkcoleman@misoenergy.org \n \nJames C. Holsclaw \nCalfee, Halter & Griswold LLP \n3900 Salesforce Tower \n111 Monument Circle \nIndianapolis, Indiana 46204 \nTelephone: 317 308-4266 \njholsclaw@calfee.com   \n \nAttorneys for the Midcontinent Independent  \nSystem Operator, Inc. \nDated: October 13, 2026"},{"page":35,"startToken":9436,"endToken":9521,"text":"35 \nCERTIFICATE OF SERVICE \nI hereby certify that I have this day e-served a copy of this document upon all parties \nlisted on the official service list compiled by the Secretary in the above-captioned proceeding, in \naccordance with the requirements of Rule 2010 of the Commission’s Rules of Practice and \nProcedure 18 C.F.R. § 385.2010. \nDated this 13th day of October 2026, in Carmel, Indiana. \n/s/ Julie Bunn \nJulie Bunn  \nMidcontinent Independent  \nSystem Operator, Inc.  \n720 City Center Drive  \nCarmel, IN 46032  \n317-249-5400"}],"sections":[{"p":1,"at":0,"title":"Opening text","method":"opening text","endPage":3,"endAt":872,"startToken":0,"endToken":739},{"p":3,"at":872,"title":"I. BACKGROUND","method":"printed heading","endPage":3,"endAt":876,"startToken":739,"endToken":740},{"p":3,"at":876,"title":"BACKGROUND","method":"printed heading","endPage":6,"endAt":828,"startToken":740,"endToken":1534},{"p":6,"at":828,"title":"II. MOTION FOR LEAVE TO FILE ANSWER","method":"printed heading","endPage":7,"endAt":179,"startToken":1534,"endToken":1748},{"p":7,"at":179,"title":"III. ANSWER","method":"printed heading","endPage":7,"endAt":193,"startToken":1748,"endToken":1750},{"p":7,"at":193,"title":"A. MISO’S LARGE LOAD AND COMPUTATIONAL LOAD DEFINITIONS ARE JUST AND","method":"printed heading","endPage":13,"endAt":1505,"startToken":1750,"endToken":3767},{"p":13,"at":1505,"title":"B. THE TRANSITION PROVISIONS REASONABLY PROTECTS EXISTING COMMERCIAL","method":"printed heading","endPage":21,"endAt":885,"startToken":3767,"endToken":5874},{"p":21,"at":885,"title":"C. THE IRR PROPOSAL PROPERLY PLACES CORE REQUIREMENTS IN THE TARIFF","method":"printed heading","endPage":26,"endAt":1153,"startToken":5874,"endToken":7295},{"p":26,"at":1153,"title":"D. MISCELLANEOUS COMMENTS AND PROTESTS.","method":"printed heading","endPage":32,"endAt":496,"startToken":7295,"endToken":8833},{"p":32,"at":496,"title":"E. CONCLUDING ARGUMENTS","method":"printed heading","endPage":34,"endAt":4,"startToken":8833,"endToken":9259},{"p":34,"at":4,"title":"IV. NOTICE AND SERVICE","method":"printed heading","endPage":34,"endAt":569,"startToken":9259,"endToken":9344},{"p":34,"at":569,"title":"V. CONCLUSION","method":"printed heading","endPage":34,"endAt":573,"startToken":9344,"endToken":9345},{"p":34,"at":573,"title":"CONCLUSION","method":"printed heading","endPage":35,"endAt":4,"startToken":9345,"endToken":9437},{"p":35,"at":4,"title":"CERTIFICATE OF SERVICE","method":"printed heading","endPage":35,"endAt":533,"startToken":9437,"endToken":9521}]}