MISO LLWG 05/14 Summary: Data Center Reliability, ZGIA & Reserve Enhancements

MISO LLWG 05/14 Meeting Summary

1. MISO LLWG 05/14 Overview

The May 14, 2026, MISO Large Load Working Group meeting focused on how MISO is preparing for the rapid growth of large loads, especially computational loads such as data centers, AI facilities, and high-performance computing campuses. These facilities can create reliability challenges because they may ramp quickly, disconnect suddenly, or behave differently from traditional industrial loads. 

MISO’s overall objective is to develop a coordinated framework for studying, interconnecting, monitoring, and operating large loads without creating unacceptable risks to the transmission system. The meeting focused on four major workstreams: Large Load Interconnection Reliability Requirements, the Zero-Injection Generator Interconnection Agreement framework, reliable operations requirements, and reserve product enhancements. 

2. Large Load Interconnection Reliability Requirements 

A major part of the meeting focused on MISO’s proposed Large Load Interconnection Reliability Requirements, with a tariff filing targeted for June 30, 2026. These requirements are intended to establish enforceable obligations for large load customers before and after energization. 

MISO’s proposed large load definition generally applies to new load or load modifications of 50 MW or more at a single site after September 1, 2026, or increases of 25 MW or more for existing loads already above 50 MW. MISO also distinguished between computational loads and traditional non-computational loads. Computational loads are expected to face stricter requirements because they can create fast ramping, sudden load loss, ride-through concerns and potential oscillatory behavior. 

The proposed requirements focus on four areas: ramp limits, data and modeling requirements, telemetry and forecasting, and ride-through and stability assessments. 

MISO proposed a net ramp-rate limit at the Point of Withdrawal, initially referencing 30 MW/minute. The purpose is to prevent sudden changes in demand that could affect balancing, voltage control and contingency response. Stakeholders requested more technical justification for the 30 MW/minute value and asked whether ramp limits should depend on local system strength, facility size, technology type, or mitigation measures. MISO clarified that the ramp limit would apply at the campus level, not to individual equipment, giving customers flexibility to use BESS, UPS systems, controls, or other smoothing technologies. 

MISO also emphasized the need for better visibility into large load facilities. Large Load Customers may be required to provide one-line diagrams, electrical characteristics, load composition, validated models, real-time telemetry, disturbance monitoring data, short-term and long-term forecasts, and outage coordination information. Stakeholders asked for more clarity on model requirements, PMU applicability, telemetry ownership, cybersecurity, sampling rates, data retention, and forecast accuracy. MISO indicated that many details will be developed through a future Large Load Business Practice Manual. 

For ride-through, MISO proposed that applicable large loads remain connected during voltage and frequency disturbances where technically feasible. Stakeholders were concerned that generator-style standards should not be directly applied to loads. MISO responded by narrowing the focus mainly to computational and electronically controlled loads. MISO also discussed stability requirements, including a potential limit on repetitive active power oscillations at the Point of Withdrawal, although stakeholders requested additional technical support and scalability analysis. 

3. Zero-Injection Generator Interconnection Agreement Framework 

MISO also reviewed the proposed Zero-Injection Generator Interconnection Agreement, or ZGIA, framework. This proposal is intended for co-located generation and load arrangements where a generator serves an associated load but does not inject net power into the transmission system. 

Under the ZGIA proposal, generator output would be limited so it does not exceed the associated load demand. The associated load would still be treated as firm Network Load and studied through normal planning processes. ZGIA resources may participate in resource adequacy and markets, but their accreditation would be limited by the associated load forecast. 

MISO clarified that the associated load could continue receiving firm service even if the ZGIA resource is offline. ZGIA resources must also be independently metered and modeled. Stakeholders raised questions about settlement treatment, congestion costs, outage treatment, forced outages, accreditation, and operational monitoring. Feedback on the ZGIA draft tariff language is due May 29, 2026, with filing activity expected in June 2026. 

4. NERC Large Load Action Plan 

NERC activity was discussed because it directly overlaps with MISO’s proposed framework. NERC issued a Level 3 Essential Actions Alert on May 4, 2026, focused on computational load modeling, studies, instrumentation, commissioning, operations, protection, and control. Applicable responses are due August 3, 2026. 

NERC emphasized that computational loads create unique reliability risks due to their size, speed, electronic controls, and potential for sudden load reduction. NERC is also developing registration criteria and reliability standards for computational loads. Draft criteria included a proposed threshold of 20 MW or more of aggregated computational load at an interconnection point of 60 kV and above. NERC also highlighted the need for high-speed monitoring, including fault recording, disturbance recording, sequence-of-events data, oscillation detection, and model validation. 

5. Reliable Operations and Reserve Enhancements 

MISO presented its reliable operations work plan for large loads. The main concern is that computational loads may create fast and unconventional ramping patterns that are not fully captured by traditional planning and operating tools. MISO identified the need for better network modeling, commercial modeling, day-ahead and real-time forecasting, telemetry, PMU visibility, outage coordination, and reliability assessments. 

MISO also discussed reserve product enhancements. Large loads can create both upward and downward reserve needs. A sudden increase in load requires additional supply or ramp capability, while a sudden decrease in load requires downward reserve capability. MISO is evaluating whether existing products such as Regulation, Ramp Capability, Short-Term Reserve, and Contingency Reserve need changes, and whether a new downward reserve product may be required. Feedback on reserve product enhancements is due June 4, 2026. 

6. Overall Summary 

The meeting showed that MISO is moving toward a broad large load framework covering interconnection, planning, operations, markets, telemetry, forecasting, and reliability compliance. Key open issues include the technical basis for the proposed 30 MW/minute ramp limit, final applicability criteria, EMT study triggers, PMU requirements, forecast accuracy expectations, ZGIA settlement treatment, and reserve product design. 

Overall, MISO is treating large load integration as a full lifecycle reliability issue. The proposed framework is intended to cover project interconnection, energization, real-time operations, market participation, and ongoing compliance, with computational loads receiving particular attention due to their size, speed, and operational uncertainty. 

7. Key Dates