ER26-3650-000 · 2026-10-13 · Midcontinent Independent System Operator Inc.

Motion for Leave to Answer and Answer of Midcontinent Independent System Operator Inc. to the Comments and Protests re the proposal to establish Interconnection Reliability Requirements for Large Loads

UNITED STATES OF AMERICA 
BEFORE THE 
FEDERAL ENERGY REGULATORY COMMISSION 
 
Midcontinent Independent System  
 
) 
Operator, Inc.  
 
 
 
 
) 
 
Docket No. ER26-3650-000 
 
 
 
 
 
 
 
) 
 
MOTION FOR LEAVE TO ANSWER AND ANSWER OF THE MIDCONTINENT 
INDEPENDENT SYSTEM OPERATOR, INC.  
 
The Midcontinent Independent System Operator, Inc. (“MISO”) submits1 this Motion for 
Leave to Answer and Answer (“Answer”) to the comments and protests filed in the above-
captioned docket by the Midwest TDUs,2 MISO Transmission Owners (“MISO TOs”), the North 
American Electric Reliability Corporation and Regional Entities (“NERC et al.”), the Organization 
of MISO States, Inc. (“OMS”), Entergy Services, LLC (“Entergy”), Google LLC (“Google”), the 
Large Energy Users,3 the Public Interest Organizations (“PIOs”),4 the Joint Consumer Advocates,5 
the Data Center Coalition (“DCC”), Rowan Digital Infrastructure, LLC (“Rowan”), and Verrus, 
LLC (“Verrus”).  
 
1  
See Rules 212 and 213 of the Rules of Practice and Procedure of the Federal Energy Regulatory Commission 
(“FERC” or “Commission”) (herein referred to the “Rules of Practice and Procedure”), 18 C.F.R. §§ 385.212 and 
213 (2026).  
2  
The Midwest TDUs consist of Central Municipal Power Agency/Services (“CMPAS”), Indiana Municipal Power 
Agency (“IMPA”), Missouri Joint Municipal Electric Utility Commission (“MJMEUC”), and WPPI Energy 
(“WPPI”). 
3  
The Large Energy Users consist of the Coalition of MISO Transmission Customers, Illinois Industrial Energy 
Consumers, Association of Businesses Advocating Tariff Equity (“ABATE”), NIPSCO Large Customer Group, 
Louisiana Energy Users Group, and Texas Industrial Energy Consumers. 
4  
The PIOs consist of Sierra Club, Natural Resources Defense Council, Environmental Law & Policy Center, Clean 
Wisconsin, Union of Concerned Scientists, Sustainable FERC Project, and Fresh Energy. 
5  
The Joint Consumer Advocates consist of the Iowa Office of Consumer Advocate (“Iowa OCA”), Office of the 
Illinois Attorney General (“IL OAG”), Illinois Citizens Utility Board (“IL CUB”), Michigan Attorney General, 
Michigan Citizens Utility Board (“MI CUB”), Minnesota Department of Commerce (“Commerce”), Citizens 
Utility Board of Minnesota (“MN CUB”), Wisconsin Citizens Utility Board (“WI CUB”), Citizens Action 
Coalition of Indiana, Inc., and Alliance for Affordable Energy.

2 
The comments reflect support for MISO’s Interconnection Reliability Requirements 
Proposal (“IRR Proposal”) to establish reliability requirements for Large Loads, while several 
parties request modifications or clarification regarding specific aspects of the proposal.6  The 
pleadings reflect broad agreement on the central point underlying the IRR Proposal: the 
unprecedented scale, concentration, and operating characteristics of emerging Large Loads require 
additional visibility and operational reliability tools now.  Several parties expressly support the 
proposal or its core reliability framework, while other parties seek clarification or additional detail 
regarding implementation.7  Notably, only one protest requests the revisions to be rejected and 
MISO directed to file revised requirements by the end of 2027.8  And one comment requests that 
the revisions be rejected without prejudice to MISO filing a revised proposal.9  MISO believes the 
comments reinforce that MISO has put forth a balanced proposal that provides an opportunity to 
continue to move forward with the Commission’s desired outcome to support the appropriate 
integration of large loads onto the system in a reliable, efficient and transparent way.  
The comments and protests do not demonstrate that MISO’s IRR Proposal is unjust or 
unreasonable.  Several parties propose modifications to the definitions, transition provisions, or 
implementation of the proposed Large Load requirements, while others request that additional 
requirements or implementation details be included in the Tariff rather than MISO’s Business 
Practices Manuals (“BPMs”).10  These comments present alternative approaches to particular 
 
6  
MISO Transmission Owners Comments at 3, 6-7; Organization of MISO States Comments at 2-7; Verrus 
Comments at 2-4; Google Comments at 1-5; NERC et al. Comments at 6-9. 
7  
Id. 
8  
PIO Protest at 2. 
9  
DCC Protest at 25. 
10  DCC Protest at 3-4; Google Comments at 2,7; Entergy Protest at 4-17; Southern Regulators Protest at 1-2; PIO 
Protest at 17-22.

3 
aspects of MISO’s proposal, but do not establish that the framework proposed by MISO fails to 
satisfy the requirements of Section 205 of the Federal Power Act.11  MISO’s proposal establishes 
requirements addressing the necessary visibility into Large Loads and their operation, including 
information, modeling, telemetry, and forecasting requirements, while also proposing specific 
requirements necessary to address the operational characteristics of Computational Loads.12 
The Commission should therefore accept the IRR Proposal without delaying its 
implementation or requiring MISO to expand this proceeding to resolve distinct large-load, 
transmission-service, or generator-interconnection issues.13  Accordingly, MISO respectfully 
requests that the IRR Proposal be accepted without modification and grant the requested effective 
date of December 4, 2026. 
I. 
BACKGROUND 
The IRR Proposal is an important near-term component of MISO’s broader response to 
rapidly accelerating Large Load development.  MISO’s 2026 Long-Term Load Forecast shows 
load growth at levels not experienced in decades, driven in substantial part by data centers, 
advanced manufacturing, and other large-load additions, some of which seek to develop on 
timelines materially shorter than traditional generation and transmission infrastructure.14  The 
North American Electric Reliability Corp (“NERC”) likewise has identified emerging 
computational loads as an increasing Bulk-Power System reliability consideration because 
conventional planning and operational assumptions may not capture the behavior of facilities that 
 
11  16 U.S.C. § 824d. 
12  IRR Proposal at 10-12, 19-26; Proposed Tariff §§ 37A.1-37A.8; Li Testimony at 12-14, 28-34. 
13  IRR Proposal at 4. 
14  IRR Proposal at 2, 7-8; Li Testimony at 5-10.

4 
are very large, capable of rapid demand changes, and increasingly dependent on power-electronic 
equipment.15  
The Commission’s June 18, 2026 Show Cause Order preliminary found that MISO’s Tariff 
appears to be unjust and unreasonable because it lacks sufficiently clear and consistent Tariff 
provisions that address certain aspects of the process to provide transmission service to Eligible 
Customers on behalf of large loads, including: (1) a definition of large load sufficient to capture 
loads that present the unique challenges described in the Show Cause Order; and (2) ongoing 
operational requirements for transmission customers serving large loads necessary to ensure 
reliable operation of the transmission system.16  In response, MISO proposed Tariff revisions 
establishing ongoing operational requirements for transmission customers taking service on behalf 
of Large Loads, including hourly forecasts, telemetry and other visibility data, communications, 
monitoring equipment, ramp rates, and ride-through requirements.17  The IRR Proposal responds 
directly to those concerns through four complementary categories of requirements: (i) visibility 
requirements, including data, modeling, telemetry, and forecasting; (ii) PMU requirements for 
Computational Loads; (iii) ramp requirements for Computational Loads; and (iv) ride-through 
requirements for Computational Loads.18  
This IRR Proposal has substantial support.  The MISO Transmission Owners support the 
IRR Proposal as a just and reasonable framework that complements MISO’s other Large Load 
 
15  IRR Proposal at 2-3, 7-8; NERC, Essential Action to Industry - Computational Load Modeling, Studies, 
Instrumentation, Commissioning, Operations, Protection, and Control May 4, 2026. 
16  Show Cause Order at P 57. 
17  Midcontinent Indep. Sys. Operator, Inc., 195 FERC ¶ 61,212, at P 64 (2026) (“Show Cause Order”); IRR Proposal 
at 6. 
18  IRR Proposal at 3-4, 9; Li Testimony at 10-11.

5 
initiatives.19  OMS generally supports the framework, including visibility, PMU, ramp, and ride-
through requirements, and supports implementing requirements now while broader NERC 
standards continue to develop.20  Verrus supports MISO’s risk-scaled applicability and its use of 
the Tariff for core obligations with BPMs for implementation detail.21  NERC and the Regional 
Entities recognize that the IRR Proposal appears generally consistent with pending Reliability 
Standards efforts and describe MISO’s work as one contribution to advancing reliability while 
NERC and industry work in parallel.22  
MISO recognizes that NERC and industry are working to mitigate the immediate reliability 
risks associated with computational load and does not intend the IRR Proposal to unnecessarily 
diverge from NERC’s developing framework.  At the same time, MISO recognizes that some 
NERC requirements, such as ride-through, will not begin development until 2027 and the urgency 
of immediate reliability risks necessitates NERC, MISO, and other stakeholders to act in parallel 
rather than sequentially; NERC recognizes this urgency as well.23  MISO has coordinated its 
proposal with emerging NERC guidance, and its stakeholder process expressly considered 
NERC’s Large Load and Computational Load work.24  NERC Project 2026-02 is itself moving 
rapidly: the initial posting was authorized August 19, 2026, and initial ballots on the first set of 
Computational Load standards concluded September 18, 2026.25  MISO will continue coordinating 
 
19  MISO Transmission Owners Comments at 3, 6-7. 
20  OMS Comments at 2-7. 
21  Verrus Comments at 2-4. 
22  NERC et al. Comments at 6-9. 
23  NERC et. al. Comments at 7. 
24  IRR Proposal at 28-30; Li Testimony at 36-39. 
25  NERC, Project 2026-02 Computational Loads, Project Status (accessed Oct. 6, 2026).

6 
with NERC and will evaluate conforming changes as NERC’s registration criteria and Reliability 
Standards become final.  
With the IRR Proposal, MISO is proposing to implement one part of a reliability-based 
framework to support the interconnection and ongoing operational challenges of Large Loads 
within the MISO region.  The objective is to establish scalable, technically justified, and risk-
informed expectations that improve visibility into large load behavior, support planning and 
operational readiness, and preserve reliable operation of the Transmission System and Bulk 
Electric System.  The proposed framework is intended to complement existing and developing 
MISO planning, interconnection, and operational processes and align, to the extent practical, with 
emerging NERC guidance and industry practices. 
II. 
MOTION FOR LEAVE TO FILE ANSWER 
 
 
Under the Commission’s rules, answers to protests generally are not permitted.26  
Nonetheless, the Commission waives this requirement where an otherwise prohibited answer 
would clarify the issues under consideration, ensure completeness of the record or assist the 
Commission in its decision-making.27  
The comments and protests raise issues concerning the scope of MISO’s Large Load and 
Computational Load definitions, the transition framework, the division of requirements between 
the Tariff and Business Practices Manuals (“BPMs”), the responsibilities of Transmission 
Customers, and the operational forecasting requirements.  This Answer clarifies the record on 
 
26  See Rule 213 of the Rules of Practice and Procedure, 18 C.F.R. § 385.213(a)(2) (2026). 
27  See, e.g., Midcontinent Indep. Sys. Operator, Inc., 169 FERC ¶ 61,173, at P 24 (2019) (accepting MISO’s answer 
to protests because it assisted FERC in the decision-making process); Texas Eastern Transmission, LP, 122 FERC 
¶ 61,205, at P 8 (2008) (accepting answer that completed the record); California Indep. Operator Corp., 105 
FERC ¶ 61,284 at P 10 (2003) (accepting MISO’s answer that clarified the issues).

7 
those issues and explains why the IRR Proposal is just and reasonable as filed.  MISO therefore 
respectfully requests waiver of Rule 213(a)(2) and acceptance of this Answer. 
III. 
ANSWER 
A. 
MISO’S LARGE LOAD AND COMPUTATIONAL LOAD DEFINITIONS ARE JUST AND 
REASONABLE. 
 
1. 
The 50 MW Large Load threshold is reasonable, administratively 
clear, and consistent with emerging industry practice. 
 
The Commission should accept MISO’s Large Load definition as just and reasonable. As 
explained below, the 50 MW threshold — measured at Points of Withdrawal for facilities located 
at a single substation— (1) provides an objective, administrable screen for Large Loads; and (2) 
reflects specific characteristics of MISO’s transmission system; and (3) ensures necessary 
visibility through Section 37A; and (4) does so without a requiring a separate voltage criterion 
because applicability is already defined at the Transmission System boundary.   
First, MISO proposes to define a Large Load as Load with Demand of 50 MW or more 
associated with a facility or aggregation of facilities located at a single substation behind one or 
more Points of Withdrawal from the Transmission System and owned, operated, or controlled by 
a single entity or a coordinating group of entities; Load used exclusively for charging an Electric 
Storage Resource is excluded.28  MISO determined 50 MW was the appropriate threshold based 
on emerging industry practices, the reliability needs of the MISO region, and stakeholder 
feedback.29  For example, Southwest Power Pool’s (“SPP”) Commission-accepted HILL 
framework uses a 50 MW threshold to evaluate reliability impacts and operational requirements 
 
28  IRR Proposal at 10-11; proposed Tariff Module A, § 1.L (Definition of “Large Load”); Li Testimony at 11-13. 
29  IRR Proposal at 10-11; Li Testimony at 12-13.

8 
for load connected above 69 kV.30  NERC’s ongoing Computational Load initiative likewise has 
considered registration thresholds in this range, and the current process is expressly intended to 
align new computational-load functional entities with revisions to NERC Rules of Procedure 
Appendix 5B.31  Consistent with NERC’s recent developments, a 50 MW threshold is a reasonable 
and effective screening criterion, because it is sufficient to identify those loads whose individual 
operating characteristics warrants enhanced visibility to determine where specific requirements 
may be appropriate to address the identifiable aggregate risks to the transmission system.  Further, 
a 50 MW threshold is sufficiently material to warrant the Section 37A visibility requirements 
because it is consistent with NERC analysis that determined a 50 MW threshold captures the vast 
majority of computational load entities that pose aggregate risks to the Bulk Power System.32  
Second, MISO’s footprint includes long transmission lines, constrained flowgates, and a 
diverse resource mix, all of which make large, fast-changing loads particularly consequential for 
real-time operations.  At this scale, a load’s behavior affects not only the local bus but also regional 
power flows and stability margins, making continuous visibility essential for reliable operations.  
Further, this threshold aligns with emerging NERC Technical Reasoning, which identifies that 
large, concentrated, and especially computational loads, exhibit fast-changing, electronics-driven 
characteristics that require elevated monitoring and disturbance-performance expectations.33  The 
 
30  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 13-21, 61, 64 (2026); SPP Tariff, pt. I, § 1, Definition of 
“HILL”. 
31  NERC, Project 2026-02 Computational Loads, Project Details (2026); NERC Aug. 19, 2026 Technical 
Reasoning/Appendix 5B proposal reflecting current 50 MW threshold, available at: 
https://www.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-technical-
reasoning.pdf. 
32  NERC, Proposed Computation Load Owner and Computational Load Operator, at 3. 
(https://prod.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-technical-
reasoning.pdf)  
33  See NERC, Appendix 5B Technical Reasoning - Proposed Computational Load Entity (August 19,2026); 
available at: https://www.nerc.com/globalassets/who-we-are/rules-of-procedure/proposed/august-posting-
technical-reasoning.pdf

9 
50 MW threshold represents the point at which load behavior becomes operationally significant 
enough that MISO system operators require additional data and performance assurance to maintain 
grid reliability.  The Commission need not require identical regional definitions, particularly where 
the Show Cause Order expressly recognized that an appropriate Large Load definition should 
reflect the characteristics of MISO’s transmission system.34  Under section 205, the Commission 
evaluates the proposal before it to determine whether it is just and reasonable and not unduly 
discriminatory or preferential.35  Multiple approaches may satisfy that standard, and MISO need 
not demonstrate that its proposed definition is the only reasonable approach or is superior to 
another potentially just and reasonable definition.36  
Third, a 50 MW threshold also is technically appropriate because loads of this size create 
material system impacts—such as rapid demand swings, voltage and frequency disturbances, and 
dynamic interactions with power-electronic equipment, that cannot be reliably managed without 
enhanced modeling, telemetry, and forecasting.  Further, the threshold is sufficiently large to 
identify concentrated load additions that warrant enhanced visibility and reliability treatment while 
providing an objective and administratively clear rule.37  The IRR Proposal also provides clear and 
objective 
aggregation 
criteria—single‑substation 
location, 
common 
or 
coordinated 
ownership/operation/control, and a 50 MW Demand threshold—which give customers advance 
notice of when aggregation applies and allow MISO to administer the rule consistently where 
 
34  Show Cause Order at P 58 (explaining that an appropriate Large Load definition, including load size and 
interconnection voltage thresholds, should be based on the characteristics of MISO’s transmission system). 
35  Advanced Energy Mgmt. All. v. FERC, 860 F.3d 656, 662 (D.C. Cir. 2017) (explaining that, in reviewing a 
section 205 filing, the Commission restricts itself to evaluating the proposal before it); 16 U.S.C. § 824d(a)–(b). 
36  Cities of Bethany v. FERC, 727 F.2d 1131, 1136 (D.C. Cir. 1984) (upholding the Commission’s evaluation of 
whether the proposed rate design was reasonable without requiring it to be superior to alternative designs); OXY 
USA, Inc. v. FERC, 64 F.3d 679, 692 (D.C. Cir. 1995) (explaining that a methodology need not be the only 
reasonable methodology or the most accurate). 
37  Li Testimony at 12-13.

10 
common ownership, operation, control, or coordinated load profiles create the potential for 
aggregated transmission-system effects.38  Contrary to the Data Center Coalition’s concern that 
aggregation is insufficiently objective, the Tariff itself supplies the relevant limiting criteria: 
single-substation location, common or coordinated control, and a 50 MW Demand threshold.39  
These criteria provide clear notice of aggregation applicability while preserving MISO’s ability to 
evaluate the system impacts and coordinated operations of coordinated facilities. These 
administrable criteria align with system behavior because the Transmission System is primarily 
impacted by the net electrical withdrawal at the point where the facilities connect, not the 
individual facilities behind that point.  Standard steady-state modeling treats such facilities as an 
equivalent aggregated load, and commonly owned or coordinated facilities typically behave as a 
unified electrical entity.  The single-substation boundary provides a clear, electrically meaningful 
point for aggregation while avoiding the inclusion of geographically dispersed and electrically 
unrelated facilities.  Even where multiple Points of Withdrawal exist, the facilities may affect 
shared substation equipment and upstream transmission facilities, resulting in a common or 
coordinated system impact.  Thus, the Tariff’s objective criteria both preserve notice and reflect 
the engineering reality of how aggregated demand interacts with upstream transmission 
equipment. 
Fourth, no separate voltage threshold is necessary because Points of Withdrawal bound 
applicability across the Transmission System.  MISO’s Tariff definition of Transmission System 
includes both facilities over which functional control has been transferred to MISO and certain 
facilities over which MISO does not have functional control.40  Appendix H of MISO’s ISO 
 
38  IRR Proposal at 10-11; Li Testimony at 12-13. 
39  DCC Protest at 20-25; proposed Tariff Module A, § 1.L, Definition of “Large Load”. 
40  Tariff Module A, supra note 29; see also Tariff Module A, § 1.T, Definition of “Transmission System”.

11 
agreement provides criteria governing the transfer of functional control of transmission facilities 
to MISO.41  Appendix H of the ISO Agreement provides the general criteria for these facilities as: 
(1) all networked facilities above 100 kV; and (2) All transformers whose two highest voltages 
qualify under the above voltage criteria; and (3) all substation equipment that forms the endpoints 
of the transmission lines in item 1, terminate the transformers in item 2, or provide voltage/stability 
control.  The transferred facilities comprise the core of the MISO Transmission System.42  MISO’s 
Transmission System also includes certain Transmission Owner facilities where functional control 
has not been transferred.  Therefore, MISO appropriately defines an administrable scope in the 
IRR Proposal without duplicative and potentially confusing voltage criteria. 
MISO’s proposed Large Load definition is just and reasonable. The 50 MW threshold is 
technically sound, regionally appropriate, operationally necessary, and administratively clear. 
Combined with measurement at Points of Withdrawal, it delivers the required visibility without 
imposing redundant voltage criteria. The Commission should approve the definition as a 
reasonable and well-supported approach to addressing the reliability concerns identified in the 
Show Cause Order. 
2. 
The Computational Load definition appropriately targets additional 
requirements to loads presenting distinct operational characteristics. 
 
MISO separately defines “Computational Load” as a Large Load comprised of 25 MW or 
more of Demand from information technology equipment, such as servers, storage, and networking 
hardware.43  This definition serves an important risk-scaling function.  All Large Loads are  subject 
to the transition provisions, to basic facility data, modeling, telemetry, forecast-data, and audit 
 
41  Tariff Rate Schedule 1.  
42  Rate Schedule 01, Art. One, § I.T (Definition of "Transmission System"). 
43  IRR Proposal at 11; proposed Tariff Module A, § 1.C, Definition of “Computational Load”; Li Testimony at 11.

12 
requirements, while the incremental PMU, ride-through, and ramp requirements apply to 
Computational Loads.44  
That distinction is supported by the record.  Computational Loads may exhibit rapid and 
coordinated changes in demand, significant power-electronic behavior, and distinct responses to 
transmission disturbances.45  The 25 MW computational component provides an objective measure 
of material computational content within an otherwise qualifying Large Load.  At the minimum 
50 MW Large Load threshold, 25 MW represents half of the facility’s Demand, providing 
quantitative context for the emerging NERC concept of facilities that primarily contain 
information-technology infrastructure.  
The unique and volatile power characteristics associated with Computational Load arise 
directly from the function of the underlying facility.  Although any individual Computational Load 
may, in isolation, appear unlikely to cause a material impact on Transmission System reliability, 
NERC has already determined through its Compliance Registry framework that entities which 
individually may not pose a material impact on reliability may nonetheless be required to register 
for applicable Reliability Standards and Requirements when the class has demonstrated to have 
such a such an impact in aggregate.46  MISO’s use of a 25 MW threshold for identifying 
Computational Load is directional aligned with NERC’s emerging Computational Load Site 
concept, which identifies computational facilities based on the presence of information-technology 
infrastructure such as servers, storage, and networking hardware.  Within MISO’s 50 MW Large 
Load applicability threshold, a 25 MW computational component provides an objective 
quantitative indicator that the facility contains material computational content and is therefore 
 
44  Proposed Tariff § 37A.I; IRR Proposal at 11-12, 22-26. 
45  IRR Proposal at 11-12; Li Testimony at 13-14. 
46  NERC Registry Criteria Revision 5.2, Notes to Criteria, note 1 (footnote excluded).

13 
likely to exhibit the characteristic behaviors of computational loads—rapid and coordinated 
demand changes, software-driven control actions, and power-electronic responses to disturbances.  
This objective threshold enables MISO to proactively apply targeted PMU, ramp-rate, and 
ride-through requirements where the electrical behavior associated with computational activity is 
predictably present, rather than waiting for those behaviors to manifest in operations, which could 
expose the system to unmitigated reliability risks. 
Google argues that reliability requirements should turn exclusively on electrical 
characteristics rather than end use, and DCC similarly seeks narrower and more predictable 
classification criteria.47  MISO agrees with the underlying principle that requirements should 
correspond to reliability risk; which is precisely why the IRR Proposal does not impose the 
incremental PMU, ramp, and ride-through requirements on every Large Load.48  The 
Computational Load definition is a reasonable proxy for the set of facilities currently known to 
present the rapid, coordinated, power-electronic behavior that motivated those requirements, and 
the Tariff authorizes MISO to determine whether Computational Load is associated with a Large 
Load based on information supplied by the Transmission Customer.49  MISO can refine 
implementation as operating experience and NERC standards develop without delaying 
protections that the record demonstrates are needed now.50  
B. 
THE TRANSITION PROVISIONS REASONABLY PROTECTS EXISTING COMMERCIAL 
ARRANGEMENTS  WITHOUT SACRIFICING RELIABILITY. 
 
1. 
The transition framework directly responds to the Show Cause Order 
and uses objective Tariff milestones. 
 
 
47  Google Comments at 5-8; DCC Protest at 20-25. 
48  IRR Proposal at 11-12; Li Testimony at 13-14. 
49  Proposed Tariff § 37A.I. 
50  IRR Proposal at 2-4, 7-9; NERC et al. Comments at 6-9.

14 
MISO’s transition framework responds to the Show Cause Order by using objective Tariff 
milestones to accommodate existing commercial arrangements and agreements nearing 
completion.  The Commission directed MISO to provide a reasonable implementation period that 
minimizes disruption to existing commercial arrangements, allows reasonable time to finalize 
ongoing agreements nearing completion when the Tariff provisions are filed, and establishes an 
effective date that accommodates those considerations.51  Paragraph 36 of the Show Cause Order 
further calls for a reasoned explanation of how the proposal will avoid disrupting existing 
commercial arrangements and an identification of a reasonable effective date that accommodates 
those arrangements.52  MISO’s framework addresses those objectives through differentiated 
treatment based on Service Commencement Date and the MTEP/EPR Condition, rather than 
requiring MISO to assess individual private contracts.53 
First, a Large Load with a Service Commencement Date on or before December 4, 2026 is 
exempt from Section 37A with respect to the portion of the Large Load that has procured 
Transmission Service as of its Service Commencement Date.54  That exemption does not 
automatically extend to subsequent increases in Transmission Service. A modification or series of 
modifications resulting in a cumulative increase of 25 MW or more, with a Service 
Commencement Date after December 4, 2026, may subject the additional Load to Section 37A’s 
requirements, depending on whether the additional Load satisfies the applicable MTEP/EPR 
Condition and other transition criteria.55  The framework therefore distinguishes the previously 
 
51  Show Cause Order at P 5; IRR Filing at 13. 
52  Show Cause Order at P 36.  
53  IRR Proposal at 13-15; Li Testimony at 23-27; proposed Tariff  
54  Proposed Tariff § 37A.II.2(a); IRR Proposal at 14-15. 
55  Id.

15 
exempt portion of the Large Load from additional Load commencing service after the effective 
date; the requirements applicable to that additional Load are determined under the Tariff’s 
transition provisions.56 
Second, a Large Load, or portion thereof, that has not commenced service by the effective 
date but satisfies the MTEP/EPR Condition remains subject to visibility requirements while 
receiving an exemption from ramp and ride-through requirements.57  Third, a Large Load, or 
portion thereof, that does not qualify for those exemptions but is associated with a transmission 
project submitted for EPR after June 18, 2026 and on or before October 31, 2026 is generally 
subject to all applicable requirements, but MISO may, however, waive the ride-through 
requirements where an exemption would not adversely affect reliability and compliance would 
impose significant costs.58  Large Loads and additional load outside specified transition categories 
are subject to all applicable requirements.59  
These provisions account for both commercial reliance and the costs of implementing new 
requirements.  The exemptions from ramp and ride-through requirements limit the potential need 
to revisit equipment selections and operating arrangements made in reliance on existing 
requirements, while the visibility requirements applicable to Load satisfying the MTEP/EPR 
Condition provide MISO with information needed to assess and manage reliability.  The limited 
ride-through waiver expressly addresses circumstances in which compliance would impose 
significant costs, but conditions relief on a determination that the exemption would not adversely 
 
56  Id. 
57  Proposed Tariff § 37A.II.2(b); IRR Proposal at 14-15.  
58  IRR Proposal at 14-15; proposed Tariff § 37A.II.2(b)-(c). 
59  IRR Proposal at 15.

16 
affect reliability.60  Significant costs alone therefore do not establish entitlement to a waiver.  This 
approach accommodates existing commercial arrangements while preserving a reliability 
assessment for the additional relief available under the waiver provision. 
These milestones are preferable to a project-by-project inquiry into private commercial 
commitments.  DCC and Rowan propose transition protection based on executed agreements, 
equipment orders, investments, or other project-maturity evidence.61 Such an approach is 
unworkable for MISO.  Treating all agreements as a sufficient determination of project maturity 
would render the requirement largely meaningless, as such agreements may not indicate actual 
commitment.  Likewise, developing prescribed contractual terms and requirements would be 
unworkable for Large Loads whose commercial arrangements do not conform to predefined 
structures.  In the alternative, requiring MISO to make an individualized determination for each 
piece of evidence would require a degree of specialized legal knowledge and commercial expertise 
that MISO does not possess and could not reasonably acquire without significant staff 
augmentation.  Even with additional staff, applying individualized determinations across a 
geographical footprint that spans 15 states will almost inevitably involve discretionary judgements 
and lead to substantial disputes.  Those considerations may be relevant to a developer’s private 
economics, but they are not uniform milestones that can reasonably be administered by MISO 
under its Tariff.  Using private contracts would require MISO to evaluate agreements entered into 
and commercial commitments made outside of MISO’s Tariff framework to determine whether 
each project is sufficiently mature, introducing variability, disputes, and inconsistent treatment.62  
By contrast, Service Commencement Date, MTEP approval, and EPR submission are objective 
 
60  Proposed Tariff § 37A.II; IRR Filing at 14-15. 
61  DCC Protest at 25-29; Rowan Protest at 3. 
62  IRR Proposal at 13-14.

17 
milestones within MISO’s own processes and are readily verifiable and consistently 
administered.63  
2. 
The transition provisions are narrowly tailored and preserve MISO’s 
authority to address material adverse reliability impacts while 
accommodating existing commercial arrangements. 
 
MISO’s transition provisions operate within an existing framework of reliability 
assessments and local planning and interconnection requirements.  MISO’s Transmission Owners 
already evaluate load additions through their planning and interconnection processes; ATC, for 
example, maintains documented local planning and load-interconnection procedures.64  Section 
37A’s ramp and ride-through requirements complement these existing practices by establishing 
consistent minimum performance expectations for Computational Loads across the MISO 
footprint. 
MISO’s transition framework provides three forms of relief.  First, qualifying Large Loads 
with a Service Commencement Date on or before December 4, 2026, are exempt from Section 
37A with respect to the portion of the Load that has procured Transmission Service as of that date.  
Second, qualifying Large Loads meeting the MTEP/EPR Condition remain subject to the 
applicable visibility and PMU requirements but are exempt from the ramp and ride-through 
requirements.  Third, eligible EPR submissions made between June 19 and October 31, 2026, 
remain subject to all applicable requirements, except that MISO may waive ride-through 
requirements upon determining that the exemption would not have an adverse reliability impact 
and compliance would result in significant costs.65  This framework thus balances the 
 
63  IRR Proposal at 13-15; Li Testimony at 23-27. 
64  Show Cause Order at P 28 & nn.74-75. 
65  Proposed Tariff § 37A.II; IRR Proposal at 14; Li Testimony at 19022.

18 
Commission’s express concern of limiting impacts to existing and near-complete commercial 
arrangements with the need to preserve reliability.66 
OMS, the PIOs, and the Joint Consumer Advocates raise concerns that the transition 
provisions could exempt a substantial quantity of existing or planned Large Load from some 
requirements.67  But the quantity of transitioned load does not establish that the transition 
framework is unjust and unreasonable.  The relevant question is how the differentiated transition 
provisions operate alongside existing reliability protections, retained information requirements, 
and MISO’s continuing authority to address reliability impacts. 
The partial exemptions do not eliminate the information requirements that enable MISO to 
evaluate reliability risks.  Large Loads qualifying for partial exemptions remain subject to basic 
facility data, modeling, telemetry, forecasting, and audit requirements, as well as PMU 
requirements where applicable, under the prescribed compliance timelines.68  These baseline 
requirements provide the real-time and planning-stage information necessary to support 
contingency analysis, operational assessments, and the evaluation of disturbance performance, 
thereby maintaining system awareness even for partially exempt facilities.  In particular, the 
modeling provisions require verified models reflecting actual facility characteristics and 
continuing updates, while the forecasting provisions require current information supporting 
commitment and dispatch.69  The IRR framework complements MISO’s existing planning, 
interconnection, and operational processes, which continue to govern reliability evaluations and 
ensure that Large Loads are incorporated into model verification, forecasting, and operational 
 
66  Show Cause Order at P 5; IRR Proposal at 13–14. 
67  OMS Comments at 4-5; PIO Protest at 1-7; Joint Consumer Advocates Protest at 2-4. 
68  Proposed Tariff § 37A.II.2(b); id. §§ 37A.1–37A.5, 37A.8. 
69  Proposed Tariff §§ 37A.2, 37A.4; Li Testimony at 26:9-14.

19 
decision-making.  Although qualifying fully exempt loads receive broader relief, the transition 
framework does not categorically exempt developing Large Loads from the visibility requirements 
needed to assess their reliability impacts. 
The transition provisions also do not create an absolute or perpetual reliability exemption.  
Section 37A expressly provides that, notwithstanding the transition provisions, MISO may require 
compliance with any or all Section 37A requirements if MISO determines that operation of a Large 
Load results in a material adverse effect on Transmission System reliability.70  Available models, 
planning assessments, operating data, and disturbance information can inform that determination 
and the identification of requirements needed to address the impact.  The process for making that 
determination and identifying which requirements must apply will be set forth in the Large Load 
BPM.71  This targeted reliability backstop preserves commercial certainty while allowing MISO 
to apply otherwise-exempt requirements where the Tariff’s reliability criterion is met.72 
To the extent a party contends that the Tariff permits a Large Load to create reliability 
concerns while constraining MISO’s ability to act, MISO respectfully clarifies that the transition 
provisions do not limit, displace existing reliability obligations, or restrict MISO’s responsibilities 
as Reliability Coordinator.  IRO-001-4 requires MISO to address reliability within its Reliability 
Coordinator Area through direct action or Operating Instructions, and requires specified entities to 
comply with those instructions subject to the standard’s stated exceptions.73  Those obligations 
apply independently of a Large Load’s transition status.  Accordingly, the PIOs’ concern that 
MISO’s hands would be tied until a Large Load causes a reliability problem conflates the specific 
 
70  Proposed Tariff § 37A.II.3. 
71  Id.  
72  IRR Proposal at 13–14; Li Testimony at 23:1–5; Proposed Tariff § 37A.II.3. 
73  NERC Reliability Standard IRO-001-4, “Reliability Coordination—Responsibilities,” Requirements R1–R3.

20 
trigger for imposing otherwise-exempt Section 37A requirements with MISO’s continuing 
operational reliability responsibilities.  The transition provisions do not require MISO to await 
actual harm before exercising its existing reliability authority. 
Finally, the IRR Proposal proceeds alongside NERC’s ongoing work to develop 
Computational Load Reliability Standards and related registration criteria.74  That work provides 
a further opportunity for alignment as industry requirements evolve; it does not justify delaying 
the near-term protections proposed here.  Together, existing local requirements, retained visibility 
obligations for partially exempt loads, the targeted Section 37A backstop, and MISO’s continuing 
Reliability Coordinator responsibilities preserve reliability while accommodating the commercial 
arrangements identified by the Commission. 
3. 
The cost-shifting arguments do not justify rejection or modification of 
the IRR transition provisions. 
 
The PIOs and Joint Consumer Advocates contend that exempting some Large Loads from 
facility-side requirements could lead to system mitigation costs that are borne by other 
customers.75  Those assertions do not establish a defect in this filing.  The IRR Proposal is directed 
to operational reliability requirements applicable to Large Load facilities and Transmission 
Customers; it does not purport to resolve the distinct questions of transmission-service design, 
study processes, or cost allocation identified in the Show Cause Order.76  
MISO is separately developing proposals to address potential cost shifts associated with 
Large Load additions, along with additional transmission service products and enhanced Large 
Load application and study processes, for filing in connection with the Commission’s November 
 
74  NERC, Project 2026-02—Computational Loads; IRR Proposal at 3. 
75  PIO Protest at 3-7; Joint Consumer Advocates Protest at 3-4. 
76  IRR Proposal at 1, 4, 9; Li Testimony at 9-11.

21 
16, 2026 deadline.77  The Commission should evaluate those cost-allocation issues on the record 
developed for those proposals rather than use speculative future cost outcomes to reject transition 
provisions that address a different and immediate reliability need.78  
4. 
Rowan’s requested transition and review clarifications do not require 
rejection of the filing. 
 
Rowan requests additional specificity concerning project-maturity evidence, waiver 
documentation, review timelines, “material modifications,” and written decision criteria.79  Many 
of these requests concern implementation procedures that MISO is continuing to develop through 
the Large Load Working Group (“LLWG”) and the Large Load BPM.80  MISO notes it is 
continuing to work with collaboratively stakeholders through the LLWG and has posted draft BPM 
language for stakeholder review and feedback.81  
C. 
THE IRR PROPOSAL PROPERLY PLACES CORE REQUIREMENTS IN THE TARIFF 
AND IMPLEMENTATION DETAIL IN THE BPMS. 
 
1. 
The Tariff contains the operative obligations and satisfies the 
Commission’s Rule of Reason. 
 
Entergy, the Southern Regulators, DCC, the PIOs, Google, and certain Large Energy Users 
argue in varying degrees that more technical detail should be placed in the Tariff rather than the 
BPMs.82  The Commission’s rule of reason requires tariff filing of provisions that significantly 
affect rates, terms, and conditions of service, are readily susceptible of specification, and are not 
 
77  IRR Proposal at 4. 
78  IRR Proposal at 1, 4. 
79  Rowan Protest at 1-3. 
80  IRR Proposal at 28-30; Li Testimony at 36-40. 
81  LLWG BPM feedback response, tag Oct 8 meeting materials and feedback request.  
82  Entergy Protest at 4-17; Southern Regulators Protest at 1-2; DCC Protest at 6-15; PIO Protest at 19-23; Google 
Comments at 7-8; Large Energy Users Protest at 7-9.

22 
generally understood in a contractual arrangement.83  It does not require every engineering 
parameter, data format, testing protocol, or implementation procedure to be frozen in a filed 
tariff.84  The Tariff appropriately balances the core details and principled requirements required 
for clarity within the tariff and the need for flexibility to address technical and administrative 
details that can mature in this particularly evolving area. 
Section 37A contains the core obligations.  It identifies who is responsible for compliance; 
which requirements apply to all Large Loads and which apply only to Computational Loads; the 
categories of required facility information and modeling; the obligation to provide real-time 
telemetry; the requirement to provide forecast data; the location and ownership framework for 
PMU equipment; the obligation of Computational Loads to ride through specified disturbances; 
the measurement framework for ramp limits, including aggregate measurement at applicable 
Points of Withdrawal and eligibility for ramp smoothing; audit rights; transition categories; and 
consequences that may follow noncompliance.85  Those are the terms that establish the parties’ 
substantive rights and obligations. 
The BPMs then provide the technical and administrative detail needed to implement those 
filed obligations consistently, including formats, timelines, technical performance curves, 
measurement intervals, validation protocols, communications specifications, and processes for 
determining remediation.86  That division is both practical and necessary in a rapidly evolving 
 
83  Midcontinent Indep. Sys. Operator, Inc., 169 FERC ¶ 61,221, at P 67 2019, citing Energy Storage Ass’n v. PJM 
Interconnection, L.L.C., 162 FERC ¶ 61,296, at P 103 2018; City of Cleveland v. FERC, 773 F.2d 1368, 1376 
D.C. Cir. 1985. 
84  See Midcontinent Indep. Sys. Operator, Inc., 170 FERC ¶ 61,075, at P 38, 2020 (accepting use of BPM detail 
where tariff contained governing requirements and noting that tariff codification could curb needed operational 
flexibility.). 
85  Proposed Tariff §§ 37A.I, 37A.1-37A.8, 37A.II; IRR Filing at 22-27. 
86  IRR Proposal at 19-21, 23-27; Li Testimony at 28-35.

23 
technical area where MISO, NERC, equipment manufacturers, Transmission Owners, and 
Transmission Customers taking Transmission Service on behalf of Large Loads are continuing to 
gain operating experience.87  
As industry gains experience with Large Loads, emerging usage patterns may provide 
insight into forecasting.  Ramp-rate limits are designed to ensure that changes in Large Load net 
demand do not pose unacceptable risk to the reliable operation of the transmission system.  
Technological advancements such as improved telemetry or enhanced forecasting may increase 
the maximum ramp-rate that the transmission system can reliably accommodate.  Because Large 
Loads rely on fast-acting controls, power-electronic interfaces, and increasingly sophisticated 
uninterruptible power supply systems, the detailed technical parameters that govern telemetry, 
PMU configuration, forecasting formats, ride-through curves, testing protocols, and ramp-rate 
measurement must remain adaptable as equipment capabilities evolve, NERC’s Computational 
Load Owner (CLO) standards finalize, and MISO gains operational experience with real-world 
Large Load behavior.  While the Tariff sets the binding reliability obligations, the technical 
implementation must evolve over time, and MISO expects continued refinement in areas such as 
telemetry resolution and data exchange methods, PMU placement and measurement settings, 
forecasting cadences, disturbance-performance envelopes, and ramp-measurement windows to 
ensure alignment with equipment capabilities, emerging NERC standards, and observed operating 
behavior. 
2. 
The Commission’s acceptance of SPP’s HILL framework confirms 
that a tariff may establish core Large Load obligations while leaving 
implementation detail outside the tariff. 
 
 
87  IRR Proposal at 2-4, 28-30; NERC et al. Comments at 6-9.

24 
The Commission recently accepted SPP’s HILL framework, which established enhanced 
study and ongoing operational requirements for high-impact loads, including nonconforming-load 
forecasting, real-time telemetry, remote-disconnect capability, a ramp-rate limit, installation of a 
PMU or similar equipment, and ride-through guidelines.88  The Commission did not require SPP’s 
tariff to reproduce every technical specification associated with each operational requirement; 
rather, the Commission accepted SPP’s ongoing operational requirements whose guidelines were 
set forth in a separate, non-tariff document.89  The relevant comparison therefore supports, rather 
than undermines, MISO’s approach: the Tariff must state the operative obligation and sufficiently 
constrain discretion, while technical implementation can be developed in manuals and guidelines. 
MISO’s proposed Tariff is clear on the fundamental categories of ongoing operational 
requirements identified by the Show Cause Order.  For example, Section 37A.7 states that 
Computational Load is subject to up- and down-ramp limits during stable-state transitions, 
measured in aggregate across applicable Points of Withdrawal, permits eligible generation or other 
resources to provide ramp smoothing, and provides for MISO to establish limits consistent with 
the BPM process.90  MISO has proposed initial up- and down-ramp limits of 30 MW/minute in its 
technical materials.91  Similarly, Section 37A.6 requires Computational Load to remain connected 
and continue operation during voltage and frequency disturbances within performance criteria 
established through the BPM, with compliance evaluated at the Points of Withdrawal.92  
 
88  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 13-21, 61, 63 (2026); Midcontinent Indep. Sys. Operator, Inc., 
195 FERC ¶ 61,212, at PP 22-23 & nn. 58-59 (2026). 
89  Sw. Power Pool, Inc., 194 FERC ¶ 61,031, at PP 20-21, 63 (2026). 
90  Proposed Tariff § 37A.7; IRR Proposal at 20, 26. 
91  IRR Proposal at 20; Li Testimony at 30-32. 
92  Proposed Tariff § 37A.6; IRR Proposal at 20-21, 25-26.

25 
MISO's initial ±30 MW/minute ramp limit establishes a reasonable, industry-informed 
baseline for managing rapid demand changes from Computational Loads.  The limit is intended to 
reduce sudden balancing needs and significant changes in transmission flows during stable-state 
transitions, while providing a consistent and predictable operating expectation.  This initial limit 
is informed by comparable industry practices and may be refined as MISO gains additional 
operating experience and develops more detailed technical criteria.  Because the Transmission 
System experiences the aggregate net demand at the applicable Points of Withdrawal (POWs), the 
ramp requirement is measured across those interfaces rather than individual computational 
equipment or load components.  This approach captures the actual impact on the Transmission 
System and provides flexibility for eligible associated generation, energy storage, uninterruptible 
power supply systems, and other load-management technologies to smooth demand changes, 
provided the resulting net ramp complies with applicable requirements.  The ride-through 
framework addresses a separate but complementary reliability concern by establishing minimum 
voltage and frequency performance expectations during system disturbances.  Applying these 
requirements with reference to the POWs supports predictable aggregate load response, reduces 
the risk of unnecessary simultaneous disconnections, and promotes stable post-disturbance 
recovery. 
3. 
MISO’s transparent stakeholder process provides additional 
protection against arbitrary implementation and supports continued BPM 
development. 
 
The premise that MISO will develop the BPM requirements without meaningful 
stakeholder input is inconsistent with the record.  MISO began discussing Large Load reliability 
requirements with stakeholders early in 2026 and repeatedly revised both Tariff and

26 
implementation concepts in response to feedback.93  At the April 20 LLWG and April 22 Planning 
Advisory Committee (“PAC”) meetings, MISO presented revised definitions and transition 
concepts; at the May 14 LLWG it provided proposed Tariff language and further revisions; at the 
June 10 LLWG it revised applicability, transition provisions, roles and responsibilities, and 
requirement-specific language based on stakeholder feedback; and at the June 29, July 16, July 27, 
and August 12 LLWG meetings it continued refining the Tariff, Technical Compendium, and 
Large Load BPM framework.94  
That process is continuing.  MISO has proposed a “hub-and-spoke” BPM architecture with 
a Large Load BPM serving as the central implementation manual and coordinated revisions to 
existing BPMs.95  MISO has separately solicited stakeholder feedback on operational forecasting, 
telemetry and PMU requirements, ride-through, ramping, and related BPM provisions.96  This 
transparent process allows technical requirements to be refined as systems and industry standards 
evolve without repeatedly reopening the Tariff for every implementation adjustment. 
D. 
MISCELLANEOUS COMMENTS AND PROTESTS. 
 
1. 
The IRR requirements apply to Transmission Customers taking 
Transmission Service on behalf of Large Loads connected to the MISO 
Transmission System. 
 
The Midwest TDUs request confirmation that Section 37A does not independently extend 
to loads interconnected only to a distribution system and that compliance obligations will not 
 
93  Li Testimony at 35-40; IRR Proposal at 28-30. 
94  Li Testimony at 35-40 & Attachment A. 
95  Li Testimony at 38-39. 
96  Large Load Working Group: Large Load Operational Forecast Requirements; Stakeholder feedback, available 
at: https://www.misoenergy.org/engage/stakeholder-feedback/2026/llwg-large-load-operational-forecast-
requirements-llwg-2026-4a-20260827/.

27 
unduly burden Transmission Customers.97  The Tariff already answers the first question.  In MISO, 
the Transmission System is used to provide Transmission Service, while the Wholesale 
Distribution System transmits energy over Distribution Facilities.98  Section 37A applies to a 
“Transmission Customer taking Transmission Service on behalf of a Large Load,” and the Large 
Load definition itself is framed by Points of Withdrawal “from the Transmission System.”99  Thus, 
the IRR Proposal does not create a free-standing MISO reliability regime for distribution-
connected load that is not taking MISO Transmission Service.100  
2. 
The Tariff reasonably assigns compliance responsibility to the 
Transmission Customer while permitting contractual arrangements and 
other documentation to demonstrate the ability to effectuate compliance. 
 
The Midwest TDUs and Rowan emphasize that the Large Load customer or equipment 
owner may control information or equipment needed for compliance.101  MISO recognizes that 
practical reality, but MISO generally lacks contractual privity with the Large Load itself.  The 
Transmission Customer, by contrast, takes Transmission Service under a service agreement 
incorporating the Tariff and therefore provides the legally enforceable relationship through which 
Section 37A can operate.102  This approach is also consistent with the Show Cause Order’s focus 
on obligations of the Eligible Customer or transmission customer taking service on behalf of the 
Large Load.103  
 
97  Midwest TDUs Comments at 1-2, 9-16. 
98  Tariff Module A, § 1.T (Definition of “Transmission Service”); id. § 1.W (Definition of “Wholesale 
Distribution Service”). 
99  Proposed Tariff § 37A.I; proposed Tariff Module A, §§ 1.L and 1.P (Definitions of “Large Load” and “Points of 
Withdrawal”). 
100  IRR Proposal at 12; Li Testimony at 14-16. 
101  Midwest TDUs Comments at 10-14; Rowan Protest at 1-2. 
102  IRR Proposal at 12-13; Li Testimony at 14-16. 
103  Show Cause Order at P 64.

28 
The proposed Tariff expressly accommodates contractual arrangements between the 
Transmission Customer and the Large Load.  A Transmission Customer must demonstrate its 
ability to effectuate compliance and provide documentation necessary for MISO to verify 
compliance; that documentation “may include applicable agreements, if any,” between the 
Transmission Customer and the entities that own, operate, or use the Large Load, or an officer 
attestation demonstrating access to the information needed for compliance.104  Thus, an agreement 
assigning relevant performance and information duties to the Large Load may be part of a 
sufficient compliance showing, although MISO must retain authority to evaluate whether the 
documentation actually enables the Transmission Customer to meet the Tariff obligation.105 
In order to ensure reliability MISO must be able to perform the Reliability Assessment 
Commitment (“RAC”) and Security Constrained Economic Dispatch (“SCED”) studies, among 
others.  Because the RAC ensures power is available to the grid, it requires inputs of forecasted 
demand, and because the SCED balances power injections with withdrawals, it requires inputs of 
ramp-rates, load forecasts, and current state estimation (telemetry). 
MISO will require load forecasts sufficient for RAC, SCED, and other reliability studies.  
In order to ensure system reliability and facilitate RAC and SCED, MISO needs telemetry, 
metering, and PMU data.  In order to study operating characteristics proactively MISO needs EMT 
model data and other equipment level model data, including protection settings, ride-through 
behavior, dynamic characteristics, staged development plans, and other operational attributes that 
are identified to materially affect reliability.  MISO would also require sufficient information to 
validate compliance with registration, modeling, and forecasting obligations, including the right 
 
104  Proposed Tariff § 37A.I. 
105  Id.

29 
to audit or verify any information submitted.  MISO must be able to obtain, through the 
Transmission Customer, all information and operational access necessary to evaluate, monitor, and 
verify Large Load behavior under Section 37A, including the facility data, electrical models, 
telemetry, PMU measurements, and forecasting inputs required to support planning studies, 
operational assessments, and disturbance-performance evaluations.  Because the Tariff designates 
the Transmission Customer as the responsible party, the Transmission Customer is required to 
“demonstrate its ability to effectuate compliance” and to provide the documentation MISO needs 
to verify adherence to Section 37A, with that documentation expressly permitted to include 
agreements or officer attestations establishing the Transmission Customer’s access to the 
information needed for compliance.  This structure ensures that MISO can obtain the visibility, 
modeling inputs, and operational coordination needed to implement the reliability requirements 
even when the end-use Large Load owns or controls specific equipment. 
Section 37A also identifies the potential consequences of noncompliance: delayed Service 
Commencement Date, time for corrective action, operational limitations, or other remediation 
necessary to maintain Transmission System reliability, with the process for determining 
appropriate measures set forth in the BPM.106  These are reliability remedies, not an automatic 
penalty schedule.  MISO will continue working with Transmission Customers and Large Loads 
through implementation to facilitate efficient compliance and provide education regarding the new 
requirements. 
3. 
The operational forecasting requirements are needed for reliability 
and should apply to Large Loads. 
 
 
106  Proposed Tariff § 37A.I.

30 
The Large Energy Users object in particular to a five-minute real-time forecasting 
requirement for non-computational Large Loads and argue that the requirement could impose costs 
on traditional industrial customers.107  Forecasting is a visibility requirement, not a computational-
load-specific performance requirement.  The Commission itself identified the absence of hourly 
forecasts and other visibility data as a potential Tariff deficiency.108  MISO’s record likewise 
explains that accurate forecasting is necessary to anticipate Large Load Demand and operating 
changes, support commitment and dispatch, and manage variability in the operational horizon.109  
Short-term operational forecasts are needed because Large Loads can change system 
conditions rapidly and cannot be forecast accurately using traditional, weather- and calendar-based 
models, making timely visibility into expected demand essential for reliable RAC, SCED, and 
other operational studies.  As Ms. Li explains, day-ahead and real-time forecasts provide MISO 
with the information needed to anticipate demand changes and maintain reliable commitment and 
dispatch, and that forecasts must be updated to reflect the most current expected conditions.110  
Although MISO’s forecasting processes operate on hourly and five-minute horizons, the 
requirement concerns forecast visibility, not an obligation for the customer to follow a five-minute 
schedule; it ensures MISO has sufficiently granular insight into facilities whose deviations may be 
operationally material.  Section 37A establishes the obligation to provide this information while 
implementation details, such as cadence, formats, and processes, are appropriately refined through 
the BPM, allowing MISO to tailor burden and accommodate practical considerations while 
preserving the reliability objective of accurate short-term forecasting. 
 
107  Large Energy Users Protest at 5-9. 
108  Show Cause Order at P 64; IRR Proposal at 6. 
109  IRR Proposal at 3, 8-9, 17-18; Li Testimony at 18-20. 
110  Li Testimony at 26.

31 
MISO’s stakeholder materials have proposed short-term forecast submissions at the 
Commercial Pricing Node (“CPNode”) level on hourly and five-minute cadences aligned with 
commitment and dispatch.111  The purpose of the five-minute data is not to presume that every 
industrial load behaves like a data center; it is to provide MISO sufficient near-term visibility into 
a 50 MW-or-larger facility whose deviations can be operationally material and impact 
Transmission System reliability.112  MISO is continuing to work with stakeholders on forecast 
horizons, submission mechanics, validation, tolerance bands, and any incentive framework, which 
are precisely the kinds of implementation details appropriately addressed through the BPM 
process.113  
MISO expects to use hourly forecasts as inputs to reliability commitment processes, 
including Multi-Day, Next-Day and Intraday RACs.  MISO expects to use five-minute forecasts 
as inputs to the Look-Ahead Commitment and UDS.  Both forecasts are required at the CPNode 
level to facilitate accurate integration of data submission into the network model for congestion 
and contingency analysis.  Large Loads can change system conditions rapidly in ways that cannot 
be reliably predicted from historical, weather-based, or calendar-based forecasting methods, which 
creates a reliability need for timely and accurate short-term operational forecasts.  Day-ahead and 
real-time forecast submissions give operators essential forward visibility into expected demand 
and enable informed commitment, dispatch, and other real-time reliability studies such as RAC 
and SCED.  Accurate short-term forecasts support situational awareness by allowing operators to 
anticipate material changes in consumption, assess the need for balancing actions, and identify 
 
111  Li Testimony at 38; MISO, Large Load Operational Forecast Requirements, LLWG on Aug. 27, 2026. 
112  Li Testimony at 8. 
113  MISO Large Load Operational Forecast Requirements Stakeholder Feedback Sessions held from August through 
September, 2026.

32 
conditions that may produce contingency risks.  The value of granular, frequently updated 
information lies in improving MISO’s ability to understand and respond to changes in Large Load 
behavior, not in imposing a requirement that customers follow a five-minute dispatch schedule.  
Because the Tariff sets only the obligation to provide timely and updated forecasts, implementation 
details, including the cadence, format, and level of granularity, have been developed through the 
BPM.  
E. 
CONCLUDING ARGUMENTS 
The IRR Proposal should be accepted as filed.  It responds directly to the Commission’s 
identified operational-reliability concerns, establishes enforceable Tariff obligations for visibility, 
PMUs, ramping, and ride-through, scales incremental requirements to Computational Loads, and 
provides a reasonable transition framework for existing and in-flight projects.114  The comments 
identify implementation questions that MISO is actively addressing through the LLWG and BPM 
process, but they do not demonstrate that the filed framework is unjust or unreasonable. 
In addition, the Commission should not delay acceptance of this filing until every related 
Large Load issue is resolved.  MISO expressly identified that transmission-service products, 
enhanced study processes, and cost-shifting protections would be addressed through separate 
proposals, and MISO continues to develop those proposals in advance of the Commission’s 
November 16, 2026 deadline.115  The immediate operational needs addressed here—that is, 
visibility, forecasting, monitoring, ramping, and disturbance performance—exist regardless of the 
final design of those later proposals.116  
 
114  IRR Proposal at 1-4, 9-27; Show Cause Order at P 64. 
115  IRR Proposal at 1, 4. 
116  IRR Proposal at 2-4, 7-9.

33 
Finally, continued use of BPMs for technical implementation is a feature of the framework, 
not a defect.  Large Load technologies, NERC standards, and MISO’s own operating experience 
are developing quickly.  The Tariff establishes the enforceable substantive obligations, while the 
BPMs allow MISO, Transmission Owners, customers, and stakeholders to refine technical 
implementation in a transparent process as experience grows.117  That structure provides the 
combination of certainty and flexibility necessary to integrate Large Loads reliably and efficiently. 
Retaining detailed technical implementation in the BPM and Technical Compendium is 
important because the Tariff establishes the core Section 37A obligations, while the underlying 
reliability needs continue to evolve with new NERC guidance, emerging Large Load technologies, 
and growing operating experience.  NERC’s work on emerging large loads highlights the need for 
ongoing refinement of modeling practices, real-time telemetry and PMU measurement 
capabilities, 
short-term 
forecasting 
methods, 
ramp-rate 
characterization, 
and 
disturbance-performance expectations as equipment designs and dynamic behaviors change over 
time.  As a result, technical parameters such as the model detail required to represent 
power-electronic controls, the resolution and configuration of telemetry and PMU data, 
assumptions used in near-term forecasting, and active-power recovery behavior during 
disturbances are expected to require periodic updates.  Housing these specifics in the BPM and 
Technical Compendium allows MISO to incorporate new standards, device capabilities, and 
operating insights without altering the fundamental reliability requirements set forth in 
Section 37A. 
 
117  IRR Proposal at 19-21, 23-30; Li Testimony at 28-40; NERC et al. Comments at 6-9.

34 
IV. 
NOTICE AND SERVICE 
MISO has served a copy of this filing electronically, including attachments, upon each 
person designated on the official service list compiled by the Secretary as well as on all Tariff 
customers, MISO Members, Member representatives of transmission owners and non-
transmission owners, as well as all state commissions within the MISO Region and the 
Organization of MISO States.  The filing has been posted electronically on MISO’s website at 
https://www.misoenergy.org/legal/ferc-filings/ for other interested parties in this matter. 
V. 
CONCLUSION  
MISO respectfully requests that the Commission (i) accept this Answer and (ii) accept the 
IRR Proposal without modification or condition.  
Respectfully submitted,  
/s/ Kalen Coleman 
Michael Kessler  
Managing Assistant General Counsel 
Kalen Coleman 
Corporate Counsel 
Midcontinent Independent System 
Operator Inc.  
720 City Center Drive 
Carmel, Indiana 46032 
Telephone: 317 249-5400 
mkessler@misoenergy.org 
kcoleman@misoenergy.org 
 
James C. Holsclaw 
Calfee, Halter & Griswold LLP 
3900 Salesforce Tower 
111 Monument Circle 
Indianapolis, Indiana 46204 
Telephone: 317 308-4266 
jholsclaw@calfee.com   
 
Attorneys for the Midcontinent Independent  
System Operator, Inc. 
Dated: October 13, 2026

35 
CERTIFICATE OF SERVICE 
I hereby certify that I have this day e-served a copy of this document upon all parties 
listed on the official service list compiled by the Secretary in the above-captioned proceeding, in 
accordance with the requirements of Rule 2010 of the Commission’s Rules of Practice and 
Procedure 18 C.F.R. § 385.2010. 
Dated this 13th day of October 2026, in Carmel, Indiana. 
/s/ Julie Bunn 
Julie Bunn  
Midcontinent Independent  
System Operator, Inc.  
720 City Center Drive  
Carmel, IN 46032  
317-249-5400