{"document":{"slug":"filing-er26-3650-miso-irr","title":"MISO proposes interconnection reliability requirements for large loads","issued":"2026-08-28","accession":"20260828-5278","docket":"ER26-3650-000","group":"MISO filings","filer":"Midcontinent Independent System Operator, Inc.","kind":"filing","file":"sources/originals/20260828-5278_01.pdf","url":"https://elibrary.ferc.gov/eLibrary/filelist?accession_Number=20260828-5278","sha256":"1538849c6d1d9693074670570c0adcaf29d33a249344052519655f6449c83e57","pages":32,"tokens":13271,"emptyPages":[]},"pages":[{"page":1,"startToken":0,"endToken":413,"text":"Midcontinent Independent \nSystem Operator, Inc. \n317.249-5400 \nwww.misoenergy.org \n720 City Center Drive \nCarmel, Indiana 46032 \n2985 Ames Crossing Road \nEagan, Minnesota 55121 \n1700 Centerview Drive \nLittle Rock, AR 72211 \n \nMichael Kessler \nManaging Assistant General Counsel \nDirect Dial:  317-753-9434 \nEmail:  mkessler@misoenergy.org \nAugust 28, 2026 \nVIA ELECTRONIC FILING \nThe Honorable Debbie-Anne Reese  \nSecretary \nFederal Energy Regulatory Commission \n888 First Street, NE \nWashington, DC  20426 \nRe: \nMidcontinent Independent System Operator, Inc.’s  \nInterconnection Reliability Requirements for Large Loads \nDocket No. ER26-___-000 \n \nDear Secretary Reese: \nThe Midcontinent Independent System Operator, Inc. (“MISO”), through this filing,1 \nsubmits proposed revisions to its Open Access Transmission, Energy and Operating Reserve \nMarkets Tariff (“Tariff”),2 to establish certain Interconnection Reliability Requirements for Large \nLoads (the “IRR Proposal”).3  The IRR Proposal is responsive to several of the concerns raised by \nthe Commission in the Order Instituting Proceeding Under Section 206 of the Federal Power Act4 \nin Docket No. EL26-70-000 by proposing visibility, ramp rate, and disturbance ride-through \nrequirements applicable to Large Loads, along with transition provisions to minimize disruption \nto commercial arrangements.  Other issues raised in the Show Cause Order, including the \ndevelopment of additional transmission products for Large Loads and associated study processes, \ncost shifting, protections against cost shifts and the treatment of generation service to electrically \nproximate to Large Loads, will be addressed through MISO’s forthcoming Large Load proposals. \n \n1  \nThis filing is made pursuant to section 205 of the Federal Power Act (“FPA”), 16 U.S.C. § 824d, and Part 35 of \nthe regulations of the Federal Energy Regulatory Commission (“FERC” or “Commission”), 18 C.F.R. § 35.1, et \nseq. \n2  \nUnless otherwise indicated by the text or context of this transmittal letter, all terms used herein have the definitions \nset forth in Module A of the Tariff. \n3  \nAs discussed below, MISO proposes to defined Large Load as Load with Demand of 50 MW or more associated \nwith any facility or aggregation of facilities located at a single substation behind one or more Point(s) of \nWithdrawal from the Transmission System that is owned, operated, or controlled by: (a) a single entity or (b) a \ngroup of entities that will coordinate with respect to the profile of the Load.  Large Load does not include Load \nused exclusively for charging an Electric Storage Resource. \n4  \nMidcontinent Independent System Operator, Inc., Order Instituting Proceeding Under Section 206 of the Federal \nPower Act, 195 FERC ¶ 61,212 (2026) (“Show Cause Order” or “SCO”)."},{"page":2,"startToken":413,"endToken":879,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 2 \n \n \nMISO requests that the Tariff revisions submitted herewith be made effective December 4, \n2026, which is not less than sixty (60) days nor more than one-hundred and twenty (120) days \nfrom the date of this filing.  As discussed below and in the supporting testimony of Ms. BeiBei Li, \naction is needed in the near term to enhance the available tools to address the reliability impacts \nassociated with the impending interconnection of Load, including the anticipated interconnection \nof significant Large Loads. \nI. \nEXECUTIVE SUMMARY \nThe MISO region is experiencing a significant increase in both the scale and pace of Large \nLoad development.  MISO’s 2026 Long-Term Load Forecast5 indicates that the region is \nexperiencing load growth at levels not seen in decades, driven in large part by unprecedented large \nload activity and accelerating project announcements.  Data centers and advanced manufacturing \nare among the primary drivers of this growth, with some projects seeking to develop on timelines \nsignificantly shorter than those traditionally associated with generation and transmission \ninfrastructure.  This combination of increased volume and accelerated development is changing \nthe manner in which MISO must plan for and reliably integrate new load.   \n \nAs this growth has emerged, MISO, its member states, and stakeholders have been \ndeveloping multiple initiatives to address evolving system conditions and to support timely, cost-\neffective and reliable interconnection of Large Loads.  For example, MISO’s Expedited Project \nReview (EPR) Process and Expedited Resource Addition Studies (ERAS) complement MISO’s \ndetermination of needed additional transmission infrastructure, which are being planned and \nimplemented through the Joint Targeted Interconnection Queue (JTIQ) and Long Range \nTransmission Plan (LRTP) processes.  An additional and critical proposal, the Zero Injection \nInterconnection Agreement (ZGIA), is currently pending action at the Commission in Docket No. \nER26-3552.  \n \nThe issuance of the Commission’s Show Cause Order has reinforced the value of MISO’s \nprior efforts with stakeholders through the stakeholder process, including most recently the Large \nLoad Working Group, to develop critical solutions to help support the cost-effective, reliable and \nefficient integration of Large Loads.  MISO continues working diligently with stakeholders on \nseveral additional initiatives in response to the Show Cause Order and is committed to bringing \nthose solutions to the Commission in a timely manner.  \n \nMISO appreciates the critical need to reliably integrate Large Loads.  Recent whitepapers \nand alerts published by the North American Electric Reliability Corporation (“NERC”) Large \nLoads Task Force and Large Loads Working Group identify emerging Large Loads as an increasing \nreliability consideration for the Bulk Electric System.  NERC guidance highlights that traditional \nplanning and operational assumptions developed for conventional load may not fully capture the \n \n5  \nSee MISO’s 2026 Long-Term Load Forecasting (LTLF) Results Summary (April 13, 2026), available \nat: https://cdn.misoenergy.org/20260413%20LTLF%20Workshop%202026%20Long%20Term%20Load%20Fo\nrecast%20Summary_UPDATED750524.pdf"},{"page":3,"startToken":879,"endToken":1298,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 3 \n \n \nbehavior or reliability impacts of emerging large loads, particularly as load facilities grow, can \nchange demand rapidly, and rely more heavily on power-electronic equipment.  \n \nWhile NERC processes are underway to develop industry wide guidelines, the MISO \nregion cannot wait to put in place needed interconnection reliability requirements to reliably \nintegrate these near-term Large Loads.  Developing standards within the MISO region in advance \nof the NERC Standards process is not new.  MISO has similarly acted in the past to establish \nrequirements for the interconnection of inverter-based resources in advance of the development of \nNERC Standards relating to such resources.  As Large Load growth accelerates across the MISO \nregion these additional reliability considerations and processes are necessary to support \ntransmission planning, operational preparedness, disturbance performance, and system stability, \nparticularly given the unique characteristics of these facilities.  \n \nTo support the integration of these new large loads into the MISO system, the IRR Proposal \nestablishes a reliability-based framework for Large Loads that complements existing MISO \nplanning, interconnection, and operational processes.  The framework is designed to improve \nvisibility into Large Load characteristics and behavior, support reliable planning and operational \ndecision-making, and establish scalable and technically justified expectations proportional to \ndemonstrated reliability risk.  The proposed framework focuses on four categories of reliability \nrequirements that will be applicable to Large Loads.  The proposed reliability requirements will \napply to MISO Transmission Customers providing Transmission Service the Large Load since the \nTransmission Customer is the entity that has a direct relationship with MISO.  The four categories \nof reliability requirements are as follows:  \n \n1. \nVisibility Requirements – Data, Modeling, Telemetry, and Forecasting \nRequirements: These requirements establish expectations for facility information, \nelectrical models, real-time telemetry, monitoring, short-term and forecasting, and \nother operational visibility requirements necessary to support planning studies, \noperational assessments, and accurate representation of Large Loads behavior and \nsystem impacts.   \n2  \nPhasor Measurement Unit (PMU) Requirements: In addition to the broader \nvisibility requirements above, the PMU requirements establish enhanced \nmonitoring expectations for Computation Loads through high-resolution, time-\nsynchronized measurements.  PMU data provides MISO with greater visibility into \nfacility behavior during system disturbances and rapid operating changes, \nsupporting model validation, performance verification, disturbance analysis, and \nidentification of potential dynamic interactions with the Transmission System. \n3. \nRamp Requirements: These requirements \naddress \nthe rate at \nwhich \nComputational Loads may increase or decrease consumption during stable-state \ntransitions.  Managing rapid changes in demand helps reduce real-time supply-\ndemand imbalances, sudden change in transmission power flows, and associated \noperational impacts, while supporting more reliable system operation.  Ramp-rate"},{"page":4,"startToken":1298,"endToken":1781,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 4 \n \n \nlimits do not apply during fault or disturbance conditions when necessary for \nequipment protection or to satisfy ride-through performance requirements. \n4. \nRide-Through Requirements: These provisions establish minimum disturbance \nperformance requirements applicable to Computational Load during voltage and \nfrequency disturbances to reduce the risk of unnecessary disconnection or \ncustomer-initiated rapid reductions in Demands during credible system events.   \nMISO recognizes that the Commission also included the need to develop a study process \nthat addresses the unique operational and reliability challenges that providing transmission service \nto Eligible Customers on behalf of large loads presents to the transmission system in its discussion \nof ongoing operational requirements in the Show Cause Order.6  MISO currently conducts such \nstudies as part of its stability assessment in the MTEP and EPR processes. The IRR Proposal \naddresses requirements applicable to Large Load facilities themselves.  MISO intends to address \nenhancements to stability assessment study processes in a future Federal Power Act section 205 \nfiling.  Those future study processes will focus on identifying system-level reliability impacts \nassociated with load additions and determining whether transmission or other system-level \nsolutions are necessary, as part of a broader set of load addition and transmission service study \nrequirements. \n   \nMISO appreciates the guidance provided by the Commission through the Show Cause \nOrders as well as its allowance for regional flexibility to develop tailored solutions that meet the \nunderlying regional needs and that can support the underlying regional processes.  The challenges \nand opportunities for large load integration differ across regions.  MISO’s expedited stakeholder \nprocess, in coordination with the MISO Transmission Owners and States, continues through the \nLarge Load Working Group.   \n \nThe previously submitted ZGIA filing and the instant IRR Proposal are the initial steps in \na broader set of solutions to address the concerns expressed by the Commission in the Show Cause \nOrder and to meet the evolving needs of the MISO region.  In addition to the ZGIA and this IRR \nProposal, MISO continues to develop a series of additional proposals that it plans to the \nCommission in advance of the November 16, 2026, deadline established based on the \nCommission’s abeyance of the Show Cause Order.  First, MISO is refining its Load Addition and \nResource Study (“LARS”) process to facilitate the parallel study of load and generation that will \naddress service to proximate load and support critical speed to power needs.  In addition, MISO is \nworking to finalize its Firm Service Step Up proposal, which will provide a practical path to \nprovide firm service increases over time as available.  In addition, MISO will work with its \nTransmission Owners and the States to develop and submit the additional proposals to: 1) provide \nadditional transmission service products to facilitate Large Load integration; 2) enhance the Large \nLoad application and study processes; and, 3) develop additional provisions to address potential \ncost-shifts associated with Large Load additions. \n \n \n6  \nShow Cause Order at P 53."},{"page":5,"startToken":1781,"endToken":2210,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 5 \n \n \nII. \nBACKGROUND \nA. \nLarge Load Challenges  \n \nThe United States is in the midst of an unprecedented energy transition.  Large Load \ncustomers, including artificial intelligence (“AI”) data centers and next-generation manufacturing \ntechnologies, are driving a surge in interconnection requests. 7  As NERC has observed, the largest \ncontributor to this accelerated demand growth is data center additions, with 18 GW of data center \nloads projected by 2035.8  The MISO region is no exception to this energy transition.  Energy-\nintensive loads such as data centers, manufacturing expansion, and electrification are adding \nsustained, concentrated load at levels not seen in decades.9  While electricity demand growth has \nbeen relatively flat with an annual average of just 0.5% between 2009 and 2024, MISO is \nprojecting a substantial increase of 1% to 2% per year through 2044, with even higher growth rates \nin the near term.10   \n \nThis growth has understandably drawn the focus of Relevant Electric Retail Rate \nAuthorities (“RERRA”), stakeholders and federal policymakers.  On January 23, 2025, President \nTrump issued an Executive Order stating, “[i]t is the policy of the United States to sustain and \nenhance America’s global AI dominance in order to promote human flourishing, economic \ncompetitiveness, and national security.”11  On July 23, 2025, an Executive Order titled \n“Accelerating Federal Permitting of Data Center Infrastructure,” the Trump Administration \nannounced its intention to pursue bold, large-scale industrial plans to incentivize critical \nmanufacturing and data center development:  \n \nWe will pursue bold, large-scale industrial plans to vault the United \nStates further into the lead on critical manufacturing processes and \ntechnologies that are essential to national security, economic \nprosperity, and scientific leadership.  These plans include artificial \nintelligence (AI) data centers and infrastructure that powers them, \nincluding high-voltage transmission lines and other equipment.  It \nwill be a priority of my Administration to facilitate the rapid and \n \n7  \nLong-Term Reliability Assessment, NERC, at 15, 25 (Jan. 2026), available at \nhttps://www.nerc.com/globalassets/our-work/assessments/nerc_ltra_2025.pdf.   \n8  \nLong-Term Reliability Assessment, NERC, at 15 (Jan. 2026), available at \nhttps://www.nerc.com/globalassets/our-work/assessments/nerc_ltra_2025.pdf.   \n9  \n2026 Reliability Imperative Report, MISO, at. 4 (Feb. 2026), available at \nhttps://cdn.misoenergy.org/2026%20Reliability%20Imperative%20Report744320.pdf.  \n10  2026 Reliability Imperative Report, MISO, at 4 (Feb. 2026), available at \nhttps://cdn.misoenergy.org/2026%20Reliability%20Imperative%20Report744320.pdf.  \n11  Executive Order 14179 of January 23, 2025, “Removing Barriers to American Leadership in Artificial \nIntelligence,” Federal Register 90 (20) 8741, www.govinfo.gov/content/pkg/FR-2025-01-31/pdf/2025-\n02172.pdf."},{"page":6,"startToken":2210,"endToken":2638,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 6 \n \n \nefficient buildout of this infrastructure by easing Federal regulatory \nburdens.12 \n \nOn October 23, 2025, the Secretary of Energy directed the Commission to consider an \nAdvance Notice of Proposed Rulemaking (“ANOPR”) focused on the timely and orderly \ninterconnection of Large Loads to the interstate transmission system.13  The Secretary’s \ncorrespondence to the Commission in support of the ANOPR emphasized the importance of the \ntimely, orderly, and non-discriminatory integration of Large Loads:   \n \nTo usher in a new era of American prosperity, we must ensure all \nAmericans and domestic industries have access to affordable, \nreliable, and secure electricity.  To do this, Large Loads, including \nAI data centers, served by public utilities must be able to connect to \nthe transmission system in a timely, orderly, and non-discriminatory \nmanner.  This is an urgent issue that requires prompt attention.14 \n \nOn June 18, 2026, the Commission issued the Show Cause Order.15  The Show Cause Order \nrecognizes the unprecedented increase in requests for transmission service to serve Large Loads \nalong with the growing interest in co-location arrangements to serve those Large Loads.16  As \nrelevant to this filing, the Show Cause Order finds that MISO’s Tariff appears to be unjust and \nunreasonable because it lacks provisions addressing ongoing operational requirements for \ntransmission customers taking transmission service on behalf of Large Loads.17  The Show Cause \nOrder raises concerns that MISO’s Tariff does not require transmission customers to provide MISO \nhourly forecasts, telemetry data, and other data to ensure sufficient visibility or specify \nrequirements for maintaining communication channels between MISO and the transmission \ncustomer on behalf of the Large Load.18  In addition, the Show Cause Order raises concerns that \nMISO’s Tariff does not specify ramp rate or ride-through requirements with which the transmission \ncustomer taking transmission service on behalf of the Large Load must comply.19  This filing \nproposes Tariff revisions establishing necessary ongoing operational requirements for Large Loads \nin response to the concerns stated in the Show Cause Order. \n \n12  Accelerating Federal Permitting of Data Center Infrastructure, Executive Order 14318, 90 FR 35385 (July 23, \n2025), https://www.whitehouse.gov/presidentialactions/2025/07/accelerating-federal-permitting-of-data-center-\ninfrastructure/.  \n13  Letter from C. Wright, Secretary of Energy, to the Federal Energy Regulatory Commission, Docket No. RM26-\n4-000 (Oct. 23, 2025).  \n14  Letter from C. Wright, Secretary of Energy, to the Federal Energy Regulatory Commission, Docket No. RM26-\n4-000 (Oct. 23, 2025).  \n15  See generally Show Cause Order.  \n16  Id. at P 1.  \n17  Id. at P 64.   \n18  Id. at P 64.  \n19  Id. at P 64."},{"page":7,"startToken":2638,"endToken":2951,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 7 \n \n \n \nB. \nAddressing the Influx of Large Loads in the MISO Region \n \nAs noted above, the MISO region is experiencing a significant increase in both the scale \nand pace of Large Load development.  As indicated in the chart below, MISO’s 2026 Long-Term \nLoad Forecast indicates that the region is experiencing load growth at levels not seen in decades, \ndriven in large part by unprecedented large load activity and accelerating project announcements.20  \nData centers and advanced manufacturing are among the primary drivers of this growth, with some \nprojects seeking to develop on timelines significantly shorter than those traditionally associated \nwith generation and transmission infrastructure.  This combination of increased volume and \naccelerated development is changing the manner in which MISO must plan for and reliably \nintegrate new load. \n \n \n \nRecent whitepapers and alerts published by the NERC Large Loads Task Force and Large \nLoads Working Group identify emerging Large Loads as an increasing reliability consideration for \nthe Bulk Electric System.21  NERC guidance highlights that traditional planning and operational \nassumptions developed for conventional load may not fully capture the behavior or reliability \nimpacts of emerging large loads, particularly as load facilities become larger, capable of rapid \ndemand changes , and increasingly interconnected with power-electronic equipment.  \n \n \n20  See MISO’s 2026 Long-Term Load Forecast (updated August 17, 2026), available at: \nhttps://cdn.misoenergy.org/20260513%20LTLF%20Whitepaper757916.pdf. \n21  See generally, Essential Action to Industry – Computational Load Modeling, Studies, Instrumentation, \nCommissioning, Operations, Protection, and Control, NERC (May 4, 2026), available at \nhttps://www.nerc.com/globalassets/programs/bpsa/alerts/level-3-computational-load-alert.pdf; Draft large Load \nDisturbance Performance, NERC (Dec. 10, 2026), available at https://www.nerc.com/globalassets/who-we-\nare/standing-committees/rstc/llwg/draft_llwg_white_paper_large_load_disturbance_performance_tosubmit.pdf;  \nProject 2026-02 Computational Load, NERC, https://www.nerc.com/standards/reliability-standards-under-\ndevelopment/2026-02-computational-loads (last visited Aug. 27, 2026)."},{"page":8,"startToken":2951,"endToken":3419,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 8 \n \n \nAccommodating accelerated interconnection of Large Loads requires MISO to ensure that \nit can reliably plan for and operate the Transmission System as these facilities come online.  Key \nreliability considerations include sufficient visibility into Large Load characteristics and operating \nbehavior, accurate forecasting and modeling, and requirements that address operational risks, such \nas rapid change in Demand, disturbance response, including ride-through capability.    \n \nMISO, its member States, and a broad and diverse group of stakeholders have been \ndeveloping multiple initiatives to address evolving system conditions and to support efficient and \nreliable interconnection of Large Loads prior to and after the issuance of the Show Cause Order.  \nFor example, MISO recently implemented the Expedited Resource Addition Study (“ERAS”) as a \ntargeted, temporary process to issue a Generator Interconnection Agreement in three months.  \nMISO also improved its Transmission Expansion Plan’s EPR process to quickly approve \ntransmission upgrades necessary to address urgent needs associated with the addition of Large \nLoads.  Further, MISO initiated the MISO-SPP Joint Targeted Interconnection Queue Study \n(“JTIQ”), which aims at building transmission network upgrades along the MISO-SPP seams to \nenable large amounts of new generation to come online in a more timely manner.   \n     \nWhile these initiatives provide important benefits, they do not fully address the reliability \nand operational challenges associated with accelerating Large Load growth.  Existing planning \nreforms primarily focus on generation additions and transmission development timelines.  \nLikewise, broader reliability initiatives were not specifically designed to address the unique \ncharacteristics and operational challenges presented by Large Load and Computational Load \nadditions.  As the size and concentration of these facilities increase, additional visibility into load \nbehavior and system interactions is necessary to support reliable operation of the Transmission \nSystem.  \n \nAccordingly, MISO recognizes that additional Tariff-based solutions are necessary to \nestablish clear reliability expectations, improve operational visibility, and facilitate timely \nintegration of Large Loads in a manner that is both reliable and non-discriminatory.  These \nsolutions must also consider and address the unique planning and operational characteristics of \nLarge Load interconnection customers and hyperscale data centers, in particular.    \n \nMISO is moving quickly and engaging with stakeholders through the Large Load Working \nGroup (“LLWG”), as well as with the Organization of MISO States, Inc. (“OMS”), in an expedited \nmanner to develop the broader set of solutions outlined in the August 3, 2026, motion filed by \nMISO and the MISO Transmission Owners to hold all proceedings related to the Show Cause \nOrder in abeyance for 90 days.22  The Abeyance Motion explained that MISO and the MISO \nTransmission Owners required additional time to continue the stakeholder process and submit FPA \n \n22  Motion of the Midcontinent Independent System Operator, Inc. and the MISO Transmission Owners to Hold \nProceeding in Abeyance and Request for Shortened Comment Period and Expedited Treatment, Docket No. \nEL26-70-000 (Aug. 3, 2026) (“Abeyance Motion”)."},{"page":9,"startToken":3419,"endToken":3734,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 9 \n \n \nsection 20523 filings that address the concerns raised in the Show Cause Order.24  The Commission \ngranted the 90-day abeyance requested in the Abeyance Motion on August 14, 2026.25    \n \nMISO has developed a prioritized work plan to accelerate consideration of the challenges \npresented by Large Load growth in the MISO region through its stakeholder process.26  This \nprocess has resulted in the development of the IRR Proposal as well as ongoing discussion of \nadditional solutions and improvements to various MISO processes, which MISO intends to submit \nfor Commission review in a series of future Federal Power Act section 205 filings.27 \nIII. \nOVERVIEW OF THE IRR PROPOSAL AND HOW IT ADDRESSES THE SHOW CAUSE ORDER \nThe IRR Proposal establishes broad categories of reliability requirements intended to \naddress planning, operational and disturbance performance associated with Large Loads, along \nwith new definitions, applicability and transition provisions necessary to implement the new \nrequirements.  A brief overview of each component of the filing is summarized below: \n \n• \nDefinitions and Applicability: Establishes which facilities qualify as Large Loads and \nComputational Loads and identifies when the requirements apply. \n \n• \nData Requirements: Establishes the facility and operational information MISO needs \nto understand Large Load characteristics and expected behavior. \n \n• \nModel Requirements: Requires appropriate electrical models so Large Loads can be \naccurately represented in MISO planning and operational analyses. \n \n• \nTelemetry Requirements: Provides real-time visibility into Large Load demand and \noperating conditions to support reliable system operations. \n \n• \nForecasting Requirements: Establishes short-term and other forecast information \nneeded to anticipate Large Load demand and operating changes. \n \n• \nPMU Requirements for Computational Loads: Provides high-resolution, time-\nsynchronized measurements to support disturbance analysis, model validation, and \nperformance verification. \n \n \n23  16 U.S.C. § 824d.  \n24  Abeyance Motion at 2.  \n25  Midcontinent Independent System Operator, Inc., et. al., 196 FERC ¶ 61,133 (August 14, 2026) (“Abeyance \nOrder”). \n26  Id. at 4.  \n27  Id."},{"page":10,"startToken":3734,"endToken":4127,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 10 \n \n \n• \nRamp Requirements for Computational Loads: Establishes limits on rapid increases \nor decreases in demand during stable-state transitions to help manage operational \nimpacts. \n \n• \nRide-Through Requirements for Computational Loads: Establishes minimum \nvoltage and frequency disturbance-performance expectations to reduce unnecessary \ndisconnection and sudden load loss. \n \n• \nImplementation and Transitional Provisions: Establishes compliance timing, \nresponsibilities, and transition mechanisms for existing and developing facilities. \n \nMISO further notes that this filing incorporates a proposed Tariff definition of “Large \nLoad.”  This proposed definition is intended to apply to this filing as well as the other filings in \nresponse to the Show Cause Order, as applicable.  \nA. \nNew Definitions Related to the IRR for Large Load \n \n \n1. \nLarge Load \nThe Order posits that MISO’s Tariff appears to be unjust and unreasonable because it lacks \na definition of Large Load sufficient to capture loads that present the unique challenges associated \nwith Large Loads.28  This filing proposes to address the Order’s concern by implementing a clear \nand consistent Large Load definition, as follows:   \nLarge Load:  Load with Demand of 50 MW or more associated with \nany facility or aggregation of facilities located at a single substation \nbehind one or more Point(s) of Withdrawal from the Transmission \nSystem that is owned, operated, or controlled by: (a) a single entity \nor (b) a group of entities that will coordinate with respect to the \nprofile of the Load.  Large Load does not include Load used \nexclusively for charging an Electric Storage Resource. \n \nAs explained by Ms. Li, MISO developed the proposed Large Load definition through a \nreview of emerging industry practices, consideration of the reliability needs in the MISO region, \nand stakeholder feedback.29  Based on that review, MISO selected a 50 MW threshold as a \nreasonable and administratively clear starting point, consistent with industry precedent and \nsufficiently significant to warrant application of MISO’s Large Load requirements.  The definition \nis based on gross load rather than net load so that MISO has visibility into the full electrical demand \nand characteristics of the facility.  Further, MISO defined Large Load at the facility or site level to \nallow loads under common ownership or coordinated operational control at a single site to be \nconsidered together, including where the site is served through multiple points of interconnection.  \n \n28  Show Cause Order at P 57. \n29  Li Testimony at p 12-13."},{"page":11,"startToken":4127,"endToken":4559,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 11 \n \n \nIn addition, Load used exclusively for charging an Electric Storage Resource is excluded as such \nLoad does not create the operational challenges associated with industrial and Computational \nLoad.30 \n \n2. \nComputational Load \nThis filing also proposes a new definition of Computational Load in order to further support \nthe consistent interpretation of the proposed reliability framework described in this filing, as \nfollows: \nComputational Load: Large Load comprised of 25 MW or more of \nDemand from information technology equipment, such as servers, \nstorage, and networking hardware. \nAs explained by Ms. Li, the Computational Load definition distinguishes a subset of Large Loads \nthat may exhibit operational characteristics different from more traditional loads, including rapid \nchanges in demand, highly coordinated control behavior, and power-electronic responses during \nsystem disturbances.31  This distinction allows MISO to apply certain incremental requirements—\nsuch as Ramp, PMU, and Ride-Through requirements—only where those characteristics warrant \nadditional reliability consideration.  The Computational Load definition is necessary as certain \nproposed requirements are intended to apply only to Large Loads with operating characteristics \nthat warrant additional reliability consideration.  Computational Loads may exhibit rapid and \ncoordinated changes in demand, significant power-electronic behavior, and distinct responses to \nTransmission System disturbances.  Defining Computational Load supports a more targeted and \nrisk-informed approach, rather than applying the same requirements to all Large Loads regardless \nof facility type or operating behavior.   \nB. \nApplicability of the Interconnection Reliability Requirements \n \nThe requirements in this filing will apply to Large Loads as established in the MISO Tariff \nand the Business Practices Manual for Large Load.  Subject to the transition provisions discussed \nbelow, all Large Loads will be subject to the applicable visibility requirements including: Basic \nFacility Data, Modeling, Telemetry, Forecast Data, and Audit requirements.  In addition, the \nComputational Load component of a Large Load, as defined in the Tariff, is subject to the PMU, \nRide-Through, and Ramp requirements.  MISO recognizes that not all Large Loads present the \nsame reliability risks and has limited the application of PMU, Ramp, and Ride-Through \nrequirements to the Computational Load component of a Large Load, which reflects the increased \noperational risk Computational Loads place on the Transmission System.  Ms. Li explains that the \nIRR Proposal is intended to provide a scalable and risk-informed framework that may be applied \n \n30  Exclusion of Load used exclusively for charging an Electric Storage Resource is consistent with the definition \nof High Impact Large Load accepted by the Commission in Southwest Power Pool, Inc., 194 FERC ¶ 61,031, \nOrder Accepting Tariff Revisions, Subject to Condition (Issued January 14, 2026).  \n31  Li Testimony at p 13-14."},{"page":12,"startToken":4559,"endToken":5096,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 12 \n \n \nin a manner proportional to demonstrated reliability need, system conditions, and facility \ncharacteristics.32 \n \nThe Transmission Customer taking Transmission Service on behalf of a Large Load will \nbe responsible for ensuring compliance by the Large Load with each of the applicable requirements \nset forth in the new Tariff section 37A.33  Requiring the Transmission Customer to ensure \ncompliance with the requirements established in the IRR Proposal is consistent with the Show \nCause Order’s discussion of imposing requirements on an “Eligible Customer” and recognizes that \nthe ultimate owner of a Large Load may not participate directly in MISO’s markets or otherwise \nhave contractual privity to MISO.  All Large Loads interconnected to the Transmission System, \nhowever, will be required to procure Transmission Service, through a Transmission Customer, \npursuant to the Tariff.  As such, the Transmission Customer will be required to enter into a \nTransmission Service agreement, which incorporates by reference the terms of the Tariff, including \nthe requirements proposed herein.  As a result, applying the requirements established in the IRR \nProposal to a Transmission Customer taking Transmission Service on behalf of a Large Load \nestablishes a legally enforceable framework though which all reliability requirements imposed on \na Large Load may be enforced. \nThe Show Cause Order indicates that MISO’s Tariff appears to be unjust and unreasonable \nbecause it lacks  pro forma provisions in a transmission service agreement between MISO and the \ntransmission customer taking transmission service on behalf of a large load to memorialize the \nongoing operational requirements similar to those proposed herein.34  The Commission notes that, \nwithout such  pro forma provisions in a transmission service agreement between MISO and the \ntransmission customer, MISO may be unable to enforce ongoing operational requirements for \ntransmission customers taking transmission service on behalf of large loads, and states that MISO \nshould explain whether the Tariff remains just and reasonable without such pro forma provisions \nin a transmission service agreement, or propose revisions to include pro forma provisions \nmemorializing the ongoing operational requirements in a transmission service agreement between \nMISO and the transmission customer.35  \nIn response to these concerns, MISO notes that the existing pro forma agreements for \nTransmission Service under MISO’s Tariff already incorporate the Tariff by reference.36 As such, \n \n32  Li Testimony at p 17. \n33  The term “Transmission Customer” is currently defined in the Tariff as: Any Eligible Customer (or its Designated \nAgent) that (i) executes a Service Agreement, or (ii) requests in writing that the Transmission Provider file with \nthe Commission, a proposed unexecuted Service Agreement to receive Transmission Service under Module B of \nthis Tariff. This term is used in the Module A, Common Tariff Provisions to include customers receiving \nTransmission Service under Module B of this Tariff, including any customer receiving HVDC Service. \n34  Show Cause Order at P 65. \n35  Id. \n36  See MISO Tariff, Attachment A – Form of Service Agreement for Short-Term Firm Point-to-Point Transmission \nService at 6.0 (The Tariff and any applicable Transaction Specification Sheet are incorporated herein and made \na part hereof.), Attachment A-1 - Form of Service Agreement for Long-Term Firm Point-to-Point Transmission \nService at 6.0 (The Tariff and any applicable Transaction Specification Sheet are incorporated herein and made"},{"page":13,"startToken":5096,"endToken":5676,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 13 \n \n \nthe Tariff will incorporate the requirements proposed herein in the applicable transmission service \nagreement for Transmission Service provided pursuant to the Tariff.  In addition, the Tariff is being \namended pursuant to Federal Power Act Section 205, which is an open, transparent process that \nprovides notice to the Transmission Customer of proposed changes to the Tariff that will apply on \nthe requested effective date.37  As such, the Commission’s concerns are addressed by the \nincorporation clause in the applicable transmission service agreements and that further revising \nthe pro forma agreements to detail additional requirements would be unnecessary and disregard \nthe flexibility afforded by the existing agreements.38  This approach would also depart from prior \npractice and Commission precedent because it could result in assumed one-off application or \nrequirements through the individual service agreement instead of the Tariff. \nC. \nTransition Provisions \nThe Order states that any filing by MISO to address the Order’s directives should “(a) \npropose a reasonable implementation period to ensure minimal disruption to such existing \ncommercial arrangements, and (b) allow a reasonable amount of time to finalize ongoing \nagreements that are nearing completion as of the date such Tariff provisions are filed with the \nCommission.  Such proposed Tariff revisions should include a reasonable effective date that \naccommodates such considerations regarding these existing commercial arrangements.”39   \nMs. Li provides that the IRR Proposal includes transition provisions that are intended to \nprovide certainty to existing commercial arrangements and commercial arrangements that were \nnear completion as of the date of this filing.40  The requirements consider the Service \nCommencement Date of the Transmission Service to serve a Large Load, whether transmission \nprojects or upgrades associated with the Large Load have been approved by the MISO Board in \n \na part hereof.), Attachment B - Form of Service Agreement for Non-Firm Point-to-Point Transmission Service \nat 8.0 (The Tariff and any applicable Exhibit WDS are incorporated herein and made a part hereof.), and \nAttachment F - Form of Service Agreement for Network Integration Transmission Service at 7.0 (The Tariff, \nTransaction Specification Sheet, Network Operating Agreement and Exhibit WDS are incorporated herein and \nmade a part hereof.).  \n37  See, e.g., W. Deptford Energy, LLC v. FERC, 766 F.3d 10 (D.C. Cir. 2014) (discussing the “notice exception” to \nthe filed rate doctrine the general rule that parties may be impacted by tariff revisions even without amendments \nto their contracts). \n38  The Commission’s regulations further support this distinction between a service agreement and the tariff under \nwhich service is provided. Under 18 C.F.R. § 35.2(c)(2), a “service agreement” is an agreement that “authorizes \na customer to take electric service under the terms of a tariff.” Thus, the service agreement does not necessarily \nfix the governing tariff as of the date of execution; rather, it authorizes service under the applicable tariff. That \nframework is reinforced by 18 C.F.R. § 35.28(c)(1) which requires transmission providers to maintain an OATT \nbased on the Commission’s pro forma tariff “as amended from time to time,” and § 35.28(c)(4) specifically \nrequires Commission-approved ISOs and RTOs to file revisions to their OATTs required by subsequent \nCommission rulemakings. Accordingly, the regulations contemplate that the tariff governing transmission \nservice will continue to change after individual service agreements have been executed. See 18 C.F.R. §§ \n35.28(c)(1) and (c)(4). \n39  Show Cause Order at P 5. \n40  Li Testimony at p 18-19."},{"page":14,"startToken":5676,"endToken":6173,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 14 \n \n \nMTEP 2026, or a prior MTEP, and when transmission projects or upgrades associated with the \nLarge Load has been submitted to the MISO EPR process.  This proposed approach recognizes the \nexisting commercial arrangements and more immediate, non-speculative, nature of the Load \nadditions and associated Transmission System upgrades. \nThe IRR Proposal proposes the following definition of “MTEP/EPR Condition” to \nfacilitate the transition provisions proposed in this filing: \n• \nFor purposes of the transition provisions, Load will satisfy the “MTEP/EPR Condition” \nif it is associated with a transmission project that either: (a) has been approved by the \nMISO Board in MTEP 2026, or a prior MTEP; or, (b) has been submitted to MISO for \nEPR on or prior to June 18, 2026, in accordance with Attachment FF of the Tariff. \nBased on this newly defined term, MISO proposes to implement the following three \ntransition provisions through the IRR Proposal:  \nFirst, MISO proposes to fully exempt, or “grandfather,” any Large Load that has a Service \nCommencement Date on or prior to December 4, 2026, from all requirements of the proposed \nSection 37A, with respect to the portion of the Large Load that has procured Transmission Service \nas of the Service Commencement Date.  Any modification or series of modifications to a Load that \nmeets the MTEP/EPR Condition, which results in a cumulative increase of 25 MW or more in \nTransmission Service for such Load and with a Service Commencement Date after December 4, \n2026, may subject the additional Load to certain requirements, depending on METP / EPR \napproval date and the Service Commencement Date of the Transmission Service for the additional \nLoad. \n \nSecond, MISO proposes that a Large Load, or a portion of a Large Load, that does not have \na Service Commencement Date prior to December 4, 2026, but that meets the MTEP/EPR \nCondition shall be subject to the visibility requirements set forth in Sections 37A.1 through 37A.5 \nand Section 37A.8, and shall be exempt from the ramp and ride-through requirements set forth in \nSections 37A.6 through 37A.7.   \n \nThird, MISO proposes that a Large Load, or a portion of Large Load, that does not have a \nService Commencement Date prior to December 4, 2026, and that has not met the MTEP/EPR \nCondition, but has submitted Load associated with a transmission project to MISO for EPR on or \nafter June 19, 2026, but on or before October 31, 2026, shall be subject to all requirements set \nforth in this Section 37A, provided that MISO may waive the ride-through requirements set forth \nin Section 37A.6 based upon a determination that: a) exemption from such requirements would \nnot have an adverse reliability impact; and, b) compliance with such requirements would result in \nsignificant costs. \n \nA Large Load that does not satisfy any of these transition provisions will be subject to all \napplicable reliability requirements, depending on whether the Large Load also qualifies as \nComputational Load."},{"page":15,"startToken":6173,"endToken":6571,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 15 \n \n \nD. \nThe Ongoing Operational Requirements for Transmission Customers Taking \nService on Behalf of Large Loads  \nThe Order posits that MISO’s Tariff appears to be unjust and unreasonable because it lacks \nprovisions addressing ongoing operational requirements for transmission customers taking \ntransmission service on behalf of Large Loads.41  The Order identified several data and other \noperational requirements it states were absent from the Tariff, including: (i) hourly forecasts, \ntelemetry data, and other data to ensure sufficient visibility or specify requirements for maintaining \ncommunication channels between MISO and the transmission customer on behalf of the Large \nLoad; (ii) equipment to enable MISO to monitor Large Loads for impacts of, for example, fast-\nramping load that may impact the transmission system too quickly to be captured by conventional \ndata acquisition systems (e.g., phasor measurement units or similar); and (iii) specified ramp rate \nor ride-through requirements.42  The Order also stated that MISO’s Tariff lacks pro forma \nprovisions in a transmission service agreement between MISO and the transmission customer \ntaking transmission service on behalf of a Large Load to memorialize the above terms (e.g., \nequipment requirements, data requirements, remote disconnect capability).43 \n1. \nBasic Facility Data and Modeling Requirements \n \na. \nReliability Objective \nMs. Li provides that the objective of the data and modeling requirements is to ensure \nsufficient visibility into the characteristics, operating behavior, and electrical performance of Large \nLoads necessary to support reliable planning, interconnection, commissioning, operations, and \npost-event analysis.44  As emerging Large Loads increasingly exhibit dynamic operating \ncharacteristics, power-electronic interfaces, and concentrated demand, additional facility \ninformation, telemetry, and modeling detail may be necessary to evaluate reliability impacts under \nboth normal and contingency conditions.  Data and modeling requirements are intended to support \nreliable operation of the Transmission System by improving the accuracy of planning assumptions, \nstrengthening operational awareness, supporting disturbance analysis and model validation, and \nenabling more consistent evaluation of system performance associated with Large Load \nintegration.  These requirements provide a framework for obtaining facility information, electrical \nmodels, telemetry, monitoring data, and operational visibility necessary to support planning \nstudies, operational assessments, commissioning activities, and reliability evaluations. \n \nConsistent with emerging industry practices and North American Electric Reliability \nCorporation (“NERC”) guidance, data and modeling expectations are intended to be scalable and \n \n41  Show Cause Order at P 64. \n42  Id. \n43  Id. at P 65. \n44  Li Testimony at p 24."},{"page":16,"startToken":6571,"endToken":6953,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 16 \n \n \nrisk-informed and may vary based on facility characteristics, operating behavior, system \nconditions, and demonstrated reliability need. \nb. \nApplicable Requirements \n \ni. Facility Data \nThe Transmission Customer will be responsible for providing MISO with basic \ninformation, one-line diagrams, and a description of the electrical characteristics of the Large Load \nfor all Large Load Equipment, in the format and consistent with the timelines specified in the \nBusiness Practice Manual for Large Load.  Any changes to the characteristics of a Large Load \nand/or Large Load Equipment, including any changes to the modeling details for the Large Load, \nshall be provided to MISO in a timely manner, consistent with the Business Practices Manual for \nLarge Load.  Such changes may include, but are not limited to, Load MW amounts, firm and non-\nfirm MW amounts, any dispatchable Load MWs, power factor, metering, telemetry, breaker \nconfiguration, staged additions and annual energy as further set forth in the Business Practices \nManual for Large Load.  \n \nThe Transmission Customer must coordinate with the Transmission Owner where the \nLarge Load Point of Withdrawal is located pursuant to MISO’s load interconnection guidance and \napplicable NERC standards. \n \nTogether, these requirements help ensure that MISO has current and accurate facility \ninformation to support planning and reliable operation of the Transmission System.45 \n \nii. Modeling Data \nThe Transmission Customer will be responsible for providing MISO with verified and \ncomplete electrical models of the Large Load, as well as detailed Load profiles, for modeled Loads, \nin the format and consistent with the timelines specified in the Business Practice Manual for \nTransmission Planning.  Such model information must include sufficient detail for MISO to \nevaluate system performance under contingency conditions in accordance with currently active \nversions of Transmission System Planning Performance Standards. \n \nFollowing completion of applicable studies and prior to the Service Commencement Date \nof the Large Load, the Transmission Customer will be responsible for providing final verified \nmodels to MISO in accordance with the Business Practices Manual for Large Load. The \nTransmission Customer will be responsible for providing notice to MISO of any material \nmodifications to the Large Load and shall not implement any such proposed modifications until \nstudied and approved by MISO in accordance with the Business Practices Manual for Large Load.   \n \n \n45  Li Testimony at p 24."},{"page":17,"startToken":6953,"endToken":7314,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 17 \n \n \nThe final models of a Large Load shall reflect the as-built configuration and actual \noperating characteristics of the Large Load and Large Load Equipment.  The Transmission \nCustomer shall maintain and update models as required by MISO. \nTogether, these requirements help ensure that MISO’s planning and reliability studies are \nbased on current and representative Large Load models. \n2. \nLoad Forecasting Requirements \n \na. \nReliability Objective \nMs. Li explains that Demand from Large Loads can fluctuate rapidly due to operational \nprocesses, making system conditions difficult to predict solely from historical weather or calendar \ndata .46  To preserve reliable commitment and dispatch, Transmission Customers serving Large \nLoads must provide timely, granular, and continuously updated short-term forecasts that MISO \ncan ingest at CPNode level and use across Reliability Assessment Commitment (RAC) and \nSecurity Constrained Economic Dispatch (SCED) processes, along with other reliability studies.  \nThese submissions give operators forward visibility into expected demand, enabling risk-aware \ncommitment, real-time balancing, reserve sufficiency, and local reliability under changing system \nconditions. \n \n \nb. \nApplicable Requirements \nPrior to the later of the Service Commencement Date of a Large Load or September 1, \n2027, the Transmission Customer must provide day(s) ahead and real-time Load Forecasts for a \nLarge Load directly to MISO to support the RAC and SCED processes, along with other reliability \nstudies.  Given the sizable reliability impact a Large Load may have on the Transmission System, \nthe Load Forecasts shall be updated to reflect the most current information on the expected \nDemand, in accordance with the Business Practices Manual for Large Load. \n3. \nTelemetry and Phasor Measurement Unit (PMU) Requirements \n \na. \nReliability Objective \nMs. Li explains that the objective of telemetry and PMU requirements is to ensure that \nMISO and Transmission Owners maintain real-time, continuous, high‑resolution visibility into \nLarge Load behavior through accurate SCADA/ICCP data and time‑synchronized phasor \nmeasurements.47   \nBecause emerging Large Loads can change real and reactive power rapidly and exhibit \npower‑electronic‑driven dynamic responses during disturbances, telemetry and, at a minimum, \nPMU live streaming enable operators to identify abnormal voltage, frequency, or oscillatory \n \n46  Li Testimony at p 26. \n47  Li Testimony at p 26-28."},{"page":18,"startToken":7314,"endToken":7681,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 18 \n \n \nconditions early, validate and refine modeling assumptions, support balancing and contingency \nanalysis, and respond effectively before issues propagate across the Bulk Electric System.  \nReliable, real‑time telemetry strengthens MISO’s ability to manage system stability, operational \nuncertainty, and disturbance performance under both normal and stressed conditions, ensuring that \nLarge Loads integrate safely and predictably into the grid. \nMISO addressed several considerations to support the telemetry reliability objective, \nincluding the following: \n• Sampling Rate and Data Quality: High‑resolution sampling (e.g., PMU‑level >60 samples \nper second) is necessary to capture fast voltage, frequency, and real/reactive power changes \ncharacteristic of power‑electronic Large Loads. \n• SCADA/ICCP Update Frequency: SCADA telemetry should provide sufficiently frequent \nupdates to support operational situational awareness and real‑time reliability assessments. \n• Phasor Measurement Unit (PMU) Integration: PMUs should be installed at the \nTransmission Owner side of the Point of Withdrawal to capture time‑synchronized \nvoltage/current phasors and event signatures that SCADA cannot detect. \n• Location of Telemetry Measurement Devices: Telemetry equipment should be installed at \nPoint of Withdrawal. \n• Communications \nInfrastructure \n& \nLatency: \nSufficient \nbandwidth, \nredundant \ncommunication paths, and low latency data streaming are essential for ensuring real‑time \nvisibility, especially for PMU data that should remain tightly time‑aligned. \n• Time Synchronization Requirements: PMUs should maintain GPS‑quality time \nsynchronization to support system‑wide correlation of events and dynamic monitoring. \n• Compatibility with MISO Telemetry Specifications: All telemetry should align with \nMISO’s ICCP, PMU streaming, and EMS data validation requirements as documented in \nrelevant BPMs and LLWG guidance. \n \nb. \nApplicable Requirements \nMISO is proposing to implement the following Telemetry and PMU requirements and \nprocedures applicable to Large Load Customers: \n \n1. Prior to the later of the Service Commencement Date of a Large Load or September 1, \n2027, a Transmission Customer must provide real-time telemetry for the Large Load, either \ndirectly, through the applicable Transmission Owner, or other Transmission Provider-\napproved communication path, in the form and manner as set forth in the Business Practices \nManual for Large Load. \n \n2. Individual metering will be required for all Large Load and any Generation Resource(s) \nserving such Large Load that is located behind the same Point of Interconnection to the"},{"page":19,"startToken":7681,"endToken":8101,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 19 \n \n \nTransmission System as the Large Load and meeting thresholds outlined in the Business \nPractices Manual for Large Load.  All telemetry shall be provided via Inter-Control Center \nCommunications Protocol (ICCP) and must meet Transmission Provider update \nrequirements as specified in the Business Practices Manual for Large Load.  The \nTransmission Customer must use commercially reasonable efforts to maintain telemetry \navailability and accuracy for the Large Load and must promptly correct erroneous data, \nbad mappings, and ICCP modeling issues. \n \n3. The Transmission Owner must provide disturbance monitoring and event recording \ncapability sufficient to support post-event analysis, model validation, and reliability \nassessment. \n \nIn addition to the requirements described above, Computational Load will be subject to the \nfollowing Phasor Measurement Unit (PMU) requirements.  Prior to the later of the Service \nCommencement Date of a Large Load or September 1, 2027, phasor measurement recording and \ncommunications equipment that is capable, at a minimum, of gathering phasor measurements must \nbe installed as specified in Business Practices Manual for Large Load.  To the extent similar quality \nequipment is being added or already exists, such as relays or digital fault recorders, that can collect \ndata at least at the same rate as PMU and which data is synchronized via a high-accuracy satellite \nclock, such equipment may be utilized to satisfy this requirement if the equipment is located on \nthe Transmission Owner’s side of the Point(s) of Withdrawal. The phasor measurement equipment \nmust be installed at the Transmission Owner’s side of the Point(s) of Withdrawal, at the \nTransmission Customer’s expense, and become part of the Transmission Owner interconnection \nfacilities.   \n4. \nRamp Requirements \n \na. \nReliability Objective \nMs. Li provides that the reliability objective of the ramp requirements is to manage \noperational impacts that can result when a Computational Load increases or decreases its Demand \nrapidly during stable-state transitions.48  Computational Loads may have the capability to change \nsignificant amounts of demand over a relatively short period of time and, in some cases, to do so \nin a highly coordinated manner.  Rapid changes of this magnitude can create short-term supply-\ndemand imbalances, cause sudden changes in transmission power flows, and increase the \noperational actions needed to maintain reliable system conditions. \n \nEstablishing reasonable limits on the rate at which a Computational Load may increase or \ndecrease its Demand provides an established operating envelope within which MISO can maintain \ngeneration-load balance and ensure the coincident risk of multiple Computational Loads does not \nresult in broader reliability impacts. \n \n \n48  Li Testimony at p 30-31."},{"page":20,"startToken":8101,"endToken":8453,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 20 \n \n \nThe proposed ramp requirements are intended to ensure that changes in Computational \nLoad demand occur at a rate that can be reliably accommodated by the Transmission System.  The \nrequirements establish up- and down-ramp limits during stable-state transitions, measured in \naggregate across the applicable Points of Withdrawal, while allowing eligible generation or other \nresources to provide ramp smoothing.  MISO is proposing initial up- and down-ramp limits of \n30MW/minute.     \n \n \n \nb. \nApplicable Requirements \nComputational Load will be subject to up-ramp and down-ramp limits during the stable-\nstate transitions, measured in aggregate across the applicable Point(s) of Withdrawal, while \nallowing eligible generation or other resource to provide ramp smoothing, consistent with the \nprocess set forth in the Business Practices Manual for Large Load.  The process to establish up-\nramp and down-ramp limits for a Computational Loads will consider local planning criteria and \nwill include a procedure for MISO to authorize or instruct deviations as may be needed to preserve \nreliability. \n5. \nRide-Through Requirements \n \n \na. \nReliability Objective \nMs. Li explains that the objective of ride-through requirements is to reduce the risk of \nunnecessary Computational Load disconnection or rapid changes in Demand during voltage and \nfrequency disturbances and support predictable disturbance performance during credible \nTransmission System events.49  As emerging Large Loads increasingly include power-electronic \ninterfaces, fast controls, and dynamic operating behavior, disturbance response may materially \naffect system performance, operational reliability, and post-contingency recovery. \n \nRide-through requirements are intended to support reliable operation of the Transmission \nSystem by improving disturbance resilience, reducing operational uncertainty associated with \nsudden changes in Computational Load demand, and promoting more predictable facility behavior \nduring transmission disturbances. These requirements establish minimum performance \nexpectations for the Computational Load component of a Large Load to maintain connection and \nstable operation during voltage and frequency excursions, while supporting system voltage \nrecovery, frequency performance, and overall system stability. \n \nConsistent with emerging industry practices and NERC guidance, the proposed ride-\nthrough expectations are intended to establish scalable and reliability-based performance criteria \nproportional to demonstrated system risk and facility operating characteristics. \n \n \nb. \nApplicable Requirements \n \n49  Li Testimony at p 32."},{"page":21,"startToken":8453,"endToken":8773,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 21 \n \n \n \n \n \n \ni. \nGeneral Principles  \nRide-through requirements apply at the facility’s Point(s) of Withdrawal (PoW(s)) and \nestablish the voltage and frequency conditions under which a Computational Loads are required \nto remain connected to the Transmission System and continue operation during disturbances. \nWhen system conditions remain within the specified ride-through performance limits, \nComputational Loads are expected to remain connected and maintain stable operation without \nunnecessary interruption of service.  As Ms. Li notes, protection and control systems should be \ncoordinated to avoid unnecessary tripping, and momentary cessation is not permitted unless \nexplicitly allowed.  Following disturbance clearance, Computational Loads are expected to recover \ntoward pre-disturbance operating conditions in a controlled manner consistent with established \nperformance expectations.50 \nMs. Li explains that the Tariff revisions proposed herein establish the core ride-through \nobligations, while the technical basis and detailed application of performance criteria supporting \nthe ride-through requirements are described in MISO’s published Large Load Technical \nCompendium, which will be incorporated into MISO’s Business Practices Manual for Large Load \nprior to the effective date of the IRR Tariff provisions.51  MISO is continuing to work with \nstakeholders on implementation details to be included in the BPM, which will address the \nfollowing items: \n• Applicability: Applies to Computational Loads subject to MISO’s ride-through \nrequirements. \n• Stay connected: Requires the facility to remain connected during qualifying voltage \nand frequency disturbances. \n• Stable operation: Requires the facility to maintain stable behavior during the \ndisturbance and avoid unnecessary tripping. \n• Post-disturbance recovery: Requires active power to recover in a controlled manner \nthat supports reliable Transmission System operation. \n• Demonstration of capability: Requires the Transmission Customer to provide models, \nstudies, equipment information, testing, or other evidence demonstrating compliance. \nIV. \nDESCRIPTION OF PROPOSED TARIFF REVISIONS \nA. \nModule A (Common Tariff Provisions).  MISO is proposing to add several new \nterms and definitions to Module A, as follows: \n \n \n50  Li Testimony at p 32-33. \n51  Li Testimony at p 33-34."},{"page":22,"startToken":8773,"endToken":9217,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 22 \n \n \n1. Computational Load:  Large Load comprised of 25 MW or more of Demand \nfrom information technology equipment, such as servers, storage, and \nnetworking hardware.  \n \n2. Large Load Equipment: Any of the facilities, devices, or equipment that \nconstitutes a part of a Large Load, or are used to interconnect the Large Load \nto the Transmission System. \n \n3. Large Load:  Load with Demand of 50 MW or more associated with any facility \nor aggregation of facilities located at a single substation behind one or more \nPoint(s) of Withdrawal from the Transmission System that is owned, operated, \nor controlled by: (a) a single entity or (b) a group of entities that will coordinate \nwith respect to the profile of the Load.  Large Load does not include Load used \nexclusively for charging an Electric Storage Resource. \n \n4. Point(s) of Withdrawal:  The point(s) where a non-transmission facility that is \nused to withdraw Energy from the Transmission System to serve Load connects \nto the Transmission System. \n \nMISO respectfully submits that these proposed definitions are just, reasonable, and \nnecessary to implement the IRR Proposal in a clear and consistent manner.  The terms were \npresented to stakeholders and iterated through MISO’s stakeholder process.  MISO worked with \nstakeholders on the definition of Large Load and related terms (i.e., Large Load Equipment, \nPoint(s) of Withdrawal, and Computational Load) and refined those terms in response to \nstakeholder feedback.  The proposed terms represent a reasonable resolution of disputed issues \nrelating to the definition of a “Large Load,” including considerations of the unique operational \ncharacteristics of Large Loads and the unique considerations within the MISO region.  The \nproposed terms also provide clarity to stakeholders, MISO, and the Commission as MISO works \nto fully address the concerns identified in the Order while ensuring that Large Loads interconnect \nin a reliable manner.  \n \nB. \nModule B (Transmission Service).  MISO is requesting approval to add new \nprovisions to Module B, as follows: \n \n1. Section 37A (Applicability of Large Load Reliability Requirements): MISO is \nproposing to implement a new subsection titled “Applicability of Large Load \nReliability Requirements.”  This proposed subsection explains that all Large \nLoad shall be subject to certain requirements as set forth in Sections37A.1 \nthrough 37A.4 and section 37A.8 of the Tariff, which are discussed below.  The \nproposed subsection also explains that Computational Load shall be subject to \nthe requirements in Sections 37A.5 through 37A.7 of the Tariff, described \nbelow.  Proposed Section 37A specifies that the Transmission Customer shall \nbe responsible for complying with the requirements of Section 37A and shall \ndemonstrate its ability to effectuate compliance with Section 37A.  Proposed"},{"page":23,"startToken":9217,"endToken":9674,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 23 \n \n \nSection 37A further explains that failure to comply with applicable \nrequirements may result in a delayed Service Commencement Date, a period of \ntime needed for corrective action, operational limitations, or other remediation \naction(s) by Transmission Provider as may be necessary to maintain \nTransmission System reliability.  This section also contains the Transition \nProvisions as discussed above.  \nMISO proposes this Section 37A in order to implement clear guidelines as to the \napplicability of the proposed requirements and to identify responsible entities.  Because Large \nLoad interconnections implicate multiple parties, clarity on those parties’ responsibilities and \nobligations is needed to streamline the interconnection process and ensure speed to power.  Further, \nclarity is required as to potential consequences in the event a party fails to comply with applicable \nrequirements.  \n2. Section 37A.1 (Large Load Information and Basic Facility Data Requirements): \nMISO is proposing a new subsection addressing Large Load information and \nbasic facility data requirements.  This proposed subsection explains that the \nTransmission Customer is responsible for providing the Transmission Provider \nwith basic information, one-line diagrams, and a description of the electrical \ncharacteristics of the Large Load for all Large Load Equipment, in the format \nand consistent with the timelines specified in the Business Practice Manual for \nLarge Load.  The proposed subsection specifies that any changes to the \ncharacteristics of a Large Load and/or Large Load Equipment shall be provided \nto the Transmission Provider in a timely manner, consistent with the Business \nPractices Manual for Large Load.  The proposed subsection further clarifies that \nthe Transmission Customer must coordinate with the Transmission Owner \nwhere the Lare Load Point(s) of Withdrawal is located pursuant to applicable \ninterconnection guidance and NERC standards. \nMISO proposes this Section 37A.1 in order to clearly identify the Large Load information \nand basic facility data requirements needed to reliably interconnect a Large Load.  The proposed \nsubsection clearly assigns responsibility among the Transmission Customer, Transmission \nProvider, and Transmission Owner, while assigning certain implementation details to the \napplicable Business Practice Manual.  MISO submits this subsection strikes a reasonable balance \nof providing sufficient guidance to applicable parties regarding the Large Load information and \nbasic facility data requirements, while offering flexibility by leaving the implementation details to \nrefinement in the Business Practices Manual.  \n3. Section 37A.2 (Large Load Modeling Requirements): MISO is proposing a new \nsubsection detailing the modeling requirements applicable to Large Loads.  This \nproposed subsection explains that the Transmission Customer shall provide the \nTransmission Provider with verified and complete electrical models of the \nLarge Load, as well as detailed Load profiles, for modeled Loads, in the format \nand consistent with the timelines specified in the Business Practice Manual for \nTransmission Planning.  The proposed subsection clarifies that this model"},{"page":24,"startToken":9674,"endToken":10145,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 24 \n \n \ninformation must include sufficient detail for Transmission Provider to evaluate \nsystem performance under contingency conditions in accordance with currently \nactive versions of Transmission System Planning Performance Standards.  The \nproposed subsection states that, following completion of applicable studies and \nprior to the Service Commencement Date of a Large Load, the Transmission \nCustomer shall submit final verified models to the Transmission Provider in \naccordance with the Business Practices Manual for Large Load and provide \nnotice to the Transmission Provider of any material modifications to the Large \nLoad.  The proposed subsection states that the final models of a Large Load \nshall reflect the as-built configuration and actual operating characteristics of the \nLarge Load and Large Load Equipment, which the Transmission Customer \nmust maintain and update as required by the Transmission Provider. \nMISO proposes this Subsection 37A.2 to provide clear modeling requirements, while \nfurther addressing the implementation details of those models to the applicable Business Practices \nManual.  The modeling requirements are reasonable and ensure that the Transmission Provider \nreceives the information necessary to model a proposed Large Load interconnection request, while \nreceiving updates to any relevant features of that proposed Large Load.  This proposed subsection \nstrikes an appropriate balance of detail between the Tariff and implementation details in the \nBusiness Practices Manual by clearly assigning responsibility to the Transmission Customer for \ndeveloping and providing modeling information, and updating its submission in response to \nchanged circumstances.   \n4. Section 37A.3 (Large Load Telemetry Requirements): MISO is proposing a \nnew subsection detailing the telemetry requirements applicable to Large Loads.  \nThe proposed subsection specifies that telemetry must be in real-time, provided \nvia an appropriate communication path, and submitted in the form and manner \nset forth in the Business Practices Manual for Large Load.  The proposed \nsubsection states that individual metering will be required (both for Large Load \nand any Generation Resource(s) serving such Large Load at the same POI), and \nthat all telemetry will be provided by via Inter-Control Center Communications \nProtocol (ICCP) and must meet Transmission Provider update requirements as \nspecified in the Business Practices Manual for Large Load.  The subsection \nstates that the Transmission Owner must provide disturbance monitoring and \nevent recording capabilities. \nMISO proposes this Subsection 37A.3 to provide clear telemetry requirements, while \naffording the flexibility to address implementation details in the Business Practices Manual.  The \ntelemetry requirements are reasonable and transparent, and provide sufficient visibility to ensure \nthe reliable interconnection of a Large Load.  The proposed subsection provides an appropriate \nbalance of detail between the Tariff and implementation details in the Business Practices Manual \nby identifying the requirements for telemetry and assigning responsibility to the applicable parties. \n5. Section 37A.4 (Large Load Forecast Data Requirements): MISO is proposing a \nnew subsection detailing the forecast data requirements for a Large Load.  The"},{"page":25,"startToken":10145,"endToken":10614,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 25 \n \n \nproposed subsection provides that, before the Service Commencement Date of \na Large Load or September 1, 2027 (whichever is later), the Transmission \nCustomer must provide day(s) ahead and real-time Load Forecasts for a Large \nLoad directly to the Transmission Provider to support the Reliability \nAssessment Commitment (RAC) and Security Constrained Economic Dispatch \n(SCED) processes, along with other reliability studies.  The Load Forecasts \nmust be updated to reflect the most current information on the expected \nDemand, in accordance with the Business Practices Manual for Large Load. \nMISO proposes this Subsection 37A.4 to ensure that Transmission Customers provide \nsufficient forecast data for a Large Load to MISO to support reliability efforts.  The subsection \nalso ensures MISO receives accurate, and up-to-date information by requiring the Transmission \nCustomer to supplement its forecast data with the most current information.  The proposed \nsubsection strikes the appropriate balance of providing all parties with sufficient detail regarding \nthe proposed forecast data requirements while leaving implementation details to the Business \nPractices Manual. \n6. Section 37A.5 (Large Load Phasor Measurement Unit Requirements): MISO is \nproposing a new subsection detailing the PMU requirements for Large Loads.  \nThe proposed subsection states that Computational Load is subject to the PMU \nrequirements.  The subsection requires PMU and recording information to be \ninstalled before the Service Commencement Date of a Large Load or September \n1, 2027 (whichever is later), and requires that this equipment gather the \nrequirements specified in the Business Practices Manual.  The proposed \nsubsections allow for the use of existing equipment to meet these requirements, \nprovided that equipment can collect data at the same rate as PMU and which \ndata is synchronized via a high-accuracy satellite clock.  The proposed \nsubsection specifies that the PMU equipment must be installed at the \nTransmission Owner’s side of the Point(s) of Withdrawal and become part of \nthe Transmission Owner interconnection facilities.   \nMISO proposes this Subsection 37A.5 to implement PMU requirements for Large Loads.  \nThe subjection ensures that those PMU requirements are satisfied by either the installation new \nequipment or a demonstration that existing equipment can serve substantially the same purpose.  \nThe subsection thus strikes a reasonable balance of requiring the installation of new equipment \nwith grandfathering existing equipment that serves substantially the same purpose.  The proposed \nsubsection also strikes the appropriate balance of providing all parties with sufficient detail of the \nPMU requirements while leaving implementation details to the Business Practices Manual. \n7. Section 37A.6 (Large Load Ride-Through Requirements): MISO is proposing \na new section for Large Load ride-through requirements.  The proposed \nsubjection provides that Computational Load shall remain connected to the \nTransmission System and continue operation during voltage and frequency \ndisturbances within the performance criteria established by the Transmission \nProvider in the Business Practices Manual for Large Load.  The proposed"},{"page":26,"startToken":10614,"endToken":11072,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 26 \n \n \nsubsection also specifies that ride-through requirements apply at the Point(s) of \nWithdrawal and may include evaluation, testing, modeling, monitoring, and \nother compliance measures established by the Transmission Provider in the \nBusiness Practices Manual for Large Load. \nMISO proposes this Subsection 37A.6 to clearly delineate the ride-through requirements \nfor Computational Load.  The proposed subsection provides clear guidance to Computational \nLoads and explains where those ride-through requirements will apply.  The proposed subsection \nalso strikes the appropriate balance of providing all parties with sufficient detail of the ride-through \nrequirements while leaving implementation details to the Business Practices Manual. \n8. Section 37A.7 (Large Load Ramp Requirements): MISO is proposing a new \nsubsection to impose Large Load ramp requirements.  The proposed subsection \nstates that Computational Load is subject to the requirements.  Ramp limits shall \nbe measured in aggregate across the applicable Point(s) of Withdrawal during \nstable-state transition, including any reduction/ramp smoothing provided by \ngeneration or other resources that meets the eligibility requirements specified \nin the Business Practices Manual for Large Load.  Computational Load shall \nalso be subject to up-ramp and down-ramp limits established by the \nTransmission Provider consistent with the process set forth in the Business \nPractices Manual for Large Load.  The proposed subsection states that the \nComputational Load must have an effective up and down ramp rate not \nexceeding the specified limit outlined in the Business Practices Manual for \nLarge Load unless otherwise directed. \nMISO proposes this Subsection 37A.7 to clearly delineate the ramp requirements for Large \nLoads.  The proposed subsection clearly identifies those parties subject to the requirements (i.e., \nComputational Load), explains how ramp limits will be measured, and specifies that MISO shall \nestablish up-ramp and down-ramp limits.  The proposed subsection also strikes the appropriate \nbalance of providing all parties with sufficient detail of the ramp requirements while leaving \nimplementation details to the Business Practices Manual. \n9. Section 37A.8 (Large Load Audit Rights): MISO is proposing a new subsection \nto implement Large Load audit rights.  The proposed subsection provides that \nthe Transmission Provider has the right to audit or verify the information \nprovided by a Transmission Customer for a Large Load and Large Load \nEquipment.  The proposed subsection states that the Transmission Customer \nshall maintain individual Large Load data and information related to the \nregistration, Load Forecasts, operations, modeling, metering, and/or settlements \nfor five (5) Years, while the Transmission Provider shall maintain individual \nLarge Load data and information it receives related to the registration, Load \nForecasts, operations, modeling, metering, and/or settlements for five (5) Years. \nMISO proposes this Subsection 37A.8 to clearly identify proposed Large Load audit rights.  \nThe subsection affords MISO the Tariff-defined authority to audit and verify information provided"},{"page":27,"startToken":11072,"endToken":11542,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 27 \n \n \nby a Transmission Customer for a Large Load, while ensuring that the information is preserved for \nat least five years.  The proposed subsection strikes a balance of ensuring that information is made \navailable to MISO and preserved for a reasonable time to complete audits, when weighed against \nany costs and burdens associated with securing such data.  The proposed subsection also strikes \nthe appropriate balance of providing all parties with sufficient detail of the audit rights while \nleaving implementation details to the Business Practices Manual. \nV. \nSTAKEHOLDER ENGAGEMENT \nMISO has engaged in detailed discussions with stakeholders on Large Load issues since \n2024 in various stakeholder entities and workshops.  MISO first discussed Large Loads with \nstakeholders in the context of Expedited Project Review process improvements at the Planning \nAdvisory Committee (“PAC”) and Planning Subcommittee (“PSC”) in 2024 and 2025.  Moreover, \nsince 2024, MISO has discussed coordinating the MISO Transmission Expansion Plan and \nDefinitive Planning Phases (“DPP”) processes to accommodate Large Loads at the PSC.  MISO \nadditionally discussed Large Load citing methodology at the November 18, 2025, Futures \nRedesign Workshop. \n \n \nMISO introduced the Large Load Interconnection Reliability Requirements at the Large \nLoads Workshop on January 30, 2026.52  The workshop addressed the challenges associated with \nreliably interconnecting Large Loads, focusing on defining reliability requirements and improving \nthe speed of integration while maintaining reliability to support member plans and goals.  \nFollowing the January 30th workshop, MISO discussed the Large Load Interconnection Reliability \nRequirements at the PAC and the Large Load Working Group (“LLWG”).  A table of meetings \ninvolving MISO’s Large Load reliability requirements development, with links to meeting \nmaterials is provided as an attachment to Ms. Li’s testimony. \n \n \nAt the February 25, 2026, PAC, MISO proposed a definition of Large Load and provided \na high-level overview of the Large Load Interconnection Reliability Requirements.  MISO \nrequested stakeholder feedback on the Large Load definition.  At the April 20, 2026, LLWG, MISO \nprovided a revised Large Load definition based on stakeholder feedback and presented the Large \nLoad Interconnection Reliability Requirements.  MISO requested feedback on the Large Load \nInterconnection Reliability Requirements.  At the April 22, 2026, PAC, MISO shared the revised \nLarge Load definition that had been shared previously at the LLWG.  MISO additionally presented \ntransition provisions it developed to address pending but unbuilt Large Load.  \n \n \nAt the May 14, 2026, LLWG, MISO responded to stakeholder feedback from the April 20 \nLLWG meeting, provided proposed Tariff language for the Large Load Interconnection Reliability \nRequirements, and provided an updated Large Load definition.  In response to stakeholder \nfeedback MISO revised the applicability language to provide additional clarity, included \ntransitional provisions that offer flexibility during implementation, and incorporated a phased-in \nimplementation to support readiness across customers and utilities.  MISO additionally updated its \n \n52  See Li Testimony, Attachment A – Table of Stakeholder Meetings."},{"page":28,"startToken":11542,"endToken":12061,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 28 \n \n \nLarge Load definition based on stakeholder feedback.  Specifically, in response to stakeholder \nfeedback regarding MISO’s initial proposal allowing multiple Points of Interconnection (“POI”), \nMISO proposed only allowing multiple POIs if the ZGIA is located at one of the stations, i.e. \nPoints of Withdrawal of a Large Load Campus.  MISO requested feedback on the Large Load \nInterconnection Reliability Requirements Tariff draft.  At the May 27, 2026, PAC, MISO presented \nthe updated Large Load definition, including the revisions to applicability and transitional \nprovisions, to ensure clarity on implementation of Interconnection Reliability Requirements.  \n \n \nAt the June 10, 2026, LLWG, MISO responded to stakeholder feedback and presented the \nTariff redlines for the Large Load Interconnection Reliability Requirements based on stakeholder \nfeedback.  Stakeholder feedback significantly influenced the revised Tariff language, particularly \naround applicability, transition provisions, and requirement specific language.  Namely, MISO: (1) \nupdated Tariff and BPM language to clarify treatment of existing loads, any expansions, and the \napplicability date; (2) updated the transitional provision to allow more flexibility; (3) updated the \nApplicability section to distinguish between Computational and Non-Computational Loads, and \napplied only ramp, PMU, ride-through, and advanced modeling requirements to Computational \nLoads; (4) updated the Large Load Customer definition to clearly define roles and responsibilities; \n(5) expanded process detail across several Tariff sections, including applicability screening, pre-\nMTEP/EPR timing, and transitional provisions for inflight projects; and (6) clarified that Tariff \napplicability for the ramp, PMU, and ride-through requirements align with NERC’s emerging \ndefinition of Computational Loads and NERC’s Load Modeling Task Force technical discussions.  \nMISO additionally revised the Large Load definition by removing the Large Load Campus \nconstruct in response to stakeholder feedback.  In addition, MISO published a technical \ncompendium outlining the technical details of the proposal that will establish the basis of the \nBusiness Practice Manual (“BPM”) for Large Load. \n \n \nAt the June 29, 2026, LLWG, MISO reviewed Tariff redlines for the Large Load definition \nand Large Load Interconnection Reliability Requirements based on stakeholder feedback.  \nStakeholder feedback significantly influenced the revised Tariff language, specifically around \napplicability, transition provisions, and requirement specific language.  MISO additionally \ndescribed how its proposed framework is consistent with the Commission’s Show Cause Order \nand noted that the framework is also in line with the emerging NERC guidance and broader \nindustry practices.  Furthermore, MISO described how its interconnection framework relies on the \nTariff to set requirements and its BPM to guide consistent implementation, noting that it is \ntargeting Large Load BPM development to take place from June to September 2026.  MISO \nrequested stakeholder feedback on the Tariff updates.  \n \nMISO separately presented on Large Load Telemetry and PMU Requirements, with the \npurpose of establishing SCADA telemetry requirements for Large Loads, and PMU requirements \nfor Computational Loads to provide situational awareness and support system reliability across the \nMISO footprint.  Specifically, MISO will require real-time SCADA telemetry from Large Loads \nvia ICCP to support real-time monitoring and analysis, and real-time SCADA telemetry from \ngeneration behind same POI as Large Load will also be required for real-time monitoring and \noptimal market dispatch; generator telemetry shall not be netted with load.  Furthermore, MISO"},{"page":29,"startToken":12061,"endToken":12530,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 29 \n \n \nwill require PMU or similar device at the Large Load with computational load to support dynamic \nmonitoring in real-time.  MISO requested stakeholder feedback on The Large Load Telemetry And \nPMU Requirements.  \n \nMISO also presented on Large Load Operation Forecast Requirements, proposing that \nLarge Loads submit short-term forecasts to reliably manage their variability.  In particular, MISO \nproposed Large Load forecast submission at the CP node level, on hourly and 5-minute cadences \naligned with commitment and dispatch and defined forecast error measurement and submission \nmonitoring, noting that it is considering mechanisms to incentivize accurate submissions.  MISO \nhighlighted that NERC has called for short-term forecast submissions from Large Loads, that SPP \nrequires them today, and that CAISO has identified the same visibility gap.  MISO requested \nstakeholder feedback on this topic.  \n \nAt the July 15, 2026, PAC, MISO informed stakeholders that the Steering Committee \napproved reassignment of the Large Load definition to the LLWG.  At the July 16, 2026 LLWG, \nMISO noted in its liaison report that there is a transition plan to manage active projects, explaining \nthat a key consideration has been ensuring reliability while avoiding disruption to loads at a late \nstage of development.  MISO noted that this consideration is reflected in the Commission’s Show \nCause Order and that it has received stakeholder feedback indicating that its current proposal does \nnot achieve this directive.  Therefore, MISO revised its approach to apply full requirements only \nto loads that MISO has not yet approved through its planning processes, and to apply visibility \nrequirements to a broader set of Large Loads.   \n \nMISO also discussed the Large Load BPM framework and development, focusing on \nchanges for interconnection and operational reliability requirements.  MISO proposed a “hub-and-\nspoke” BPM framework consisting of a new Large Load BPM, the “hub”,  supported by updates \nto existing BPMs and manuals, the “spokes.”  MISO requested stakeholder feedback on the Large \nLoad BPM framework.  \n \nAt the July 27, 2026, LLWG, MISO reviewed Tariff redlines for the Large Load definition \nand Large Load Interconnection Reliability Requirements based on stakeholder feedback.  MISO \nnoted that its BPM development timeline has been extended to December 2026.  MISO also \nprovided updates to its Technical Compendium and requested stakeholder feedback on its Tariff \nupdates. \n  \nAt the August 12, 2026, LLWG, MISO reviewed the informal stakeholder feedback on the \nreliability requirement updates provided at the July 27, 2026 LLWG.  MISO discussed the \nadditional refinements it made to its proposal based on informal stakeholder feedback.  MISO also \nheld an LLWG meeting on August 27, 2026.  For this meeting, MISO posted final Tariff language \nfor the IRR Proposal, and discussed two clarifying updates included in the Tariff language related \nto an explicit statement that Transmission Owners are required to install PMUs, at the Transmission \nCustomer’s expense, and clarifications to MISO’s Ride-Through requirements."},{"page":30,"startToken":12530,"endToken":12980,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 30 \n \n \n \nAs described above, throughout the stakeholder engagement period, MSO has solicited \nfeedback from stakeholders and provided written and verbal responses to that feedback.  MISO’s \nstakeholder process has contributed to substantive design changes in MISO’s filing and the \ncollaborative process with stakeholders resulted in a comprehensive proposal for addressing Large \nLoads in the MISO footprint.  MISO appreciates the willingness of all its stakeholders and state \nregulators to review and comment on this final proposal, which MISO believes reasonably \naccommodates concerns raised by stakeholders. \n \n \nIn addition to the stakeholder meetings, MISO’s external affairs and Large Load teams \nhave met with individual stakeholders and RERRAs to inform them about MISO’s proposal and \nanswer questions.  MISO is aware that this is a pressing topic in the MISO footprint and commits \nto working with stakeholders and RERRAs to address any questions that may arise. \n \nVI. \nDOCUMENTS SUBMITTED IN THIS FILING \nIn addition to this Transmittal Letter, this submission includes: \nTab A – Redline Tariff;53, \nTab B – Clean Tariff; and \nTab C – Prepared Direct Testimony of Beibei Li. \nVII. \nEFFECTIVE DATE AND REQUEST FOR WAIVER \nMISO requests an effective date of December 4, 2026, which is not less than sixty (60) \ndays nor more than one-hundred and twenty (120) days from the date of this filing.  As discussed \nabove and in the supporting testimony of Ms. Li, December 4, 2026, is the date after which the \nMISO Board is expected to approve the MTEP 2026 projects and aligns with the IRR transition \nprovisions described above. \nMISO also requests waiver of Section 35.13 of the Commission’s regulations, 18 C.F.R. § \n35.13 (2026), to the extent applicable to this filing, and requests waiver of any other applicable \nrequirement of 18 C.F.R. Part 35 for which waiver is not specifically requested, if necessary, in \norder to permit Commission acceptance of this filing. \n \n53  Language currently pending before the Commission in the following, unrelated dockets is highlighted in yellow: \nDocket No.  ER26-2974-000.  MISO requests that the Commission treat such highlighted language as subject to \nthe outcome of that pending proceeding.  MISO commits to file any revisions to this highlighted language as \nnecessary to comply with any Commission orders in that proceeding.   \n \nIn addition, MISO has not included language that has future effective dates of 9/1/2027 in Docket No. ER25-\n1886-000 and 6/1/2029 in Docket No. ER22-1640-003.  If needed, MISO commits to file any revisions to comply \nwith any Commission orders in these proceedings and MISO commits to make subsequent filings with the \nCommission to reflect the most up-to-date version of the then-current Tariff provisions prior to the effective dates \nof the language."},{"page":31,"startToken":12980,"endToken":13234,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 31 \n \n \n \nVIII. \nCOMMUNICATIONS \nMISO respectfully requests waiver of Rule 203(b)(3) of the Commission’s Rules of \nPractice and Procedure, 18 C.F.R. § 385.203(b)(3) (2026), to the extent necessary to permit the \ndesignation of more than two persons for service on behalf of MISO in this proceeding and requests \nall communications related to this filing be directed to: \nMichael Kessler  \nManaging Assistant General Counsel \nMidcontinent Independent System   \nOperator, Inc. \n720 City Center Drive  \nCarmel, Indiana 46032  \nTelephone: (317) 753-9434 \nmkessler@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 \nIX. \nNOTICE AND SERVICE \nMISO has served a copy of this filing electronically, including attachments, upon 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. \nX. \nCONCLUSION \nFor all of the foregoing reasons, MISO respectfully requests that the Commission accept \nthis filing and grant waiver of any Commission regulations the Commission deems in order for the \nCommission to accept it as proposed. \nRespectfully submitted, \n \n/s/ Michael Kessler \nMichael Kessler  \nManaging Assistant General Counsel \nMidcontinent Independent System   \nOperator, Inc. \n720 City Center Drive  \nCarmel, Indiana 46032  \nTelephone: (317) 753-9434 \nmkessler@misoenergy.org \n \nJames C. Holsclaw"},{"page":32,"startToken":13234,"endToken":13271,"text":"The Honorable Debbie-Anne Reese \nAugust 28, 2026 \nPage 32 \n \n \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. \nAttachments"}],"sections":[{"p":1,"at":0,"title":"Opening text","method":"opening text","endPage":2,"endAt":575,"startToken":0,"endToken":502},{"p":2,"at":575,"title":"I. EXECUTIVE SUMMARY","method":"printed heading","endPage":2,"endAt":579,"startToken":502,"endToken":503},{"p":2,"at":579,"title":"EXECUTIVE SUMMARY","method":"printed heading","endPage":5,"endAt":62,"startToken":503,"endToken":1790},{"p":5,"at":62,"title":"II. BACKGROUND","method":"printed heading","endPage":5,"endAt":67,"startToken":1790,"endToken":1791},{"p":5,"at":67,"title":"BACKGROUND","method":"printed heading","endPage":5,"endAt":79,"startToken":1791,"endToken":1792},{"p":5,"at":79,"title":"A. Large Load Challenges","method":"printed heading","endPage":7,"endAt":64,"startToken":1792,"endToken":2647},{"p":7,"at":64,"title":"B. Addressing the Influx of Large Loads in the MISO Region","method":"printed heading","endPage":9,"endAt":707,"startToken":2647,"endToken":3530},{"p":9,"at":707,"title":"III. OVERVIEW OF THE IRR PROPOSAL AND HOW IT ADDRESSES THE SHOW CAUSE ORDER","method":"printed heading","endPage":10,"endAt":847,"startToken":3530,"endToken":3840},{"p":10,"at":847,"title":"A. New Definitions Related to the IRR for Large Load","method":"printed heading","endPage":11,"endAt":1753,"startToken":3840,"endToken":4358},{"p":11,"at":1753,"title":"B. Applicability of the Interconnection Reliability Requirements","method":"printed heading","endPage":13,"endAt":1015,"startToken":4358,"endToken":5241},{"p":13,"at":1015,"title":"C. Transition Provisions","method":"printed heading","endPage":13,"endAt":2259,"startToken":5241,"endToken":5423},{"p":13,"at":2259,"title":"Attachment F - Form of Service Agreement for Network Integration Transmission Service at 7.0 (The Tariff,","method":"printed heading","endPage":15,"endAt":63,"startToken":5423,"endToken":6182},{"p":15,"at":63,"title":"D. The Ongoing Operational Requirements for Transmission Customers Taking","method":"printed heading","endPage":21,"endAt":2183,"startToken":6182,"endToken":8734},{"p":21,"at":2183,"title":"IV. DESCRIPTION OF PROPOSED TARIFF REVISIONS","method":"printed heading","endPage":21,"endAt":2230,"startToken":8734,"endToken":8740},{"p":21,"at":2230,"title":"A. Module A (Common Tariff Provisions). MISO is proposing to add several new","method":"printed heading","endPage":22,"endAt":2029,"startToken":8740,"endToken":9084},{"p":22,"at":2029,"title":"B. Module B (Transmission Service). MISO is requesting approval to add new","method":"printed heading","endPage":27,"endAt":622,"startToken":9084,"endToken":11165},{"p":27,"at":622,"title":"V. STAKEHOLDER ENGAGEMENT","method":"printed heading","endPage":30,"endAt":1035,"startToken":11165,"endToken":12678},{"p":30,"at":1035,"title":"VI. DOCUMENTS SUBMITTED IN THIS FILING","method":"printed heading","endPage":30,"endAt":1247,"startToken":12678,"endToken":12711},{"p":30,"at":1247,"title":"VII. EFFECTIVE DATE AND REQUEST FOR WAIVER","method":"printed heading","endPage":31,"endAt":65,"startToken":12711,"endToken":12989},{"p":31,"at":65,"title":"VIII. COMMUNICATIONS","method":"printed heading","endPage":31,"endAt":808,"startToken":12989,"endToken":13096},{"p":31,"at":808,"title":"IX. NOTICE AND SERVICE","method":"printed heading","endPage":31,"endAt":1280,"startToken":13096,"endToken":13165},{"p":31,"at":1280,"title":"X. CONCLUSION","method":"printed heading","endPage":31,"endAt":1284,"startToken":13165,"endToken":13166},{"p":31,"at":1284,"title":"CONCLUSION","method":"printed heading","endPage":32,"endAt":298,"startToken":13166,"endToken":13271}]}