At the January 21, 2026, MISO PAC meeting, discussions continued on how interconnection policy and planning tools must evolve to keep pace with large load growth. Building on themes raised in recent large load workshops, the MISO PAC agenda focused on three related topics: proposed revisions to Attachment GGG, the role of Zero-Injection Generator Interconnection Agreements (ZGIAs), and the status of corrections to the Generator Interconnection (GI) Workbook.
Taken together, these updates signal a deliberate effort by MISO to reduce ambiguity in its interconnection framework, better align studies with actual requested rights, and introduce near-term tools that can support large load development without undermining system reliability or long-term planning integrity.
Attachment GGG: Clarifying Scope and Limiting Misinterpretation
A central item at the MISO PAC meeting was MISO’s proposed update to Attachment GGG. Staff explained that the revisions are intended to address ongoing confusion — particularly around Merchant HVDC projects — by reinforcing a fundamental point: Attachment GGG provides electrical connection only, not transmission or deliverability rights.
Under the clarified framework, projects seeking withdrawal or delivery rights must pursue those rights explicitly through a Transmission Connection Agreement and Module B. MISO emphasized that this distinction is critical to ensuring that interconnection studies reflect the actual services requested, rather than assuming broader rights that were never formally sought.
Another important change involves narrowing the scope of studies conducted under GGG. Going forward, studies would be limited to the megawatts and rights explicitly requested by the project. This approach is intended to avoid over-studying hypothetical conditions and to reduce the risk of unnecessary or inflated upgrade requirements.
MISO also proposed introducing a Limited Operations option under Attachment GGG. This option would allow projects to operate temporarily under defined constraints, without conferring transmission or deliverability rights. Staff characterized this as a narrowly scoped, time-limited pathway designed to provide flexibility while preserving the integrity of long-term planning assumptions.
Implications for Large Loads and Speed-to-Power
While the Attachment GGG discussion was framed in technical and contractual terms, its relevance to large load integration was clear. As highlighted in MISO’s recent large load workshops, one of the dominant challenges facing the system is the mismatch between fast load development timelines and much slower generation and transmission buildouts.
By clarifying that GGG is strictly a connection mechanism and by limiting study scope to actual requested rights, MISO is attempting to reduce friction and uncertainty in the interconnection process. At the same time, the Limited Operations concept acknowledges real commercial pressure to bring projects online sooner — without allowing temporary solutions to quietly become permanent assumptions in planning models.
From a system perspective, these changes reflect an effort to strike a balance: enabling faster initial connections where appropriate, while maintaining clear guardrails around reliability, deliverability, and cost allocation.
Zero-Injection Generator Interconnection Agreements (ZGIAs)
MISO also discussed Zero-Injection Generator Interconnection Agreements as part of its evolving large-load strategy. ZGIAs recognize on-site generation that is electrically connected but cannot inject power into the grid. This configuration is increasingly relevant for large loads such as data centers that pair on-site generation with load for reliability or emissions objectives, without exporting power.
MISO framed ZGIAs as a practical, near-term tool that can support large loads by offsetting some transmission impacts while maintaining system reliability. Because zero-injection resources do not export energy, they can be treated differently in interconnection studies, potentially reducing the scope or cost of required network upgrades.
However, MISO also emphasized that ZGIAs are not a workaround for broader interconnection requirements. The operational behavior, controls, and protections associated with zero-injection facilities must be clearly defined and enforced to ensure that they do not introduce unmodeled risks during contingencies or abnormal system conditions.
GI Workbook Corrections and Planning Sensitivity
Separately, MISO provided an update on the Generator Interconnection Workbook. Staff noted that a correction window opened in September 2025 resulted in more than 200 correction requests, representing roughly 3 GW of capacity. Due to the volume and complexity of submissions, MISO extended its review through the end of the year, with an updated workbook expected by the end of January.
Several stakeholders raised concerns during the PAC discussion that the scale of these corrections could have unintended consequences for planning assumptions. In particular, there was concern that revised capacity values could inadvertently flow into Definite Planning Phase (DPP) models, potentially skewing study results if not carefully managed.
MISO acknowledged these concerns and indicated that adjustments may be necessary to ensure that planning models remain aligned with verified project status and realistic development expectations. This exchange underscored the sensitivity of planning inputs at a time when both generation and load portfolios are changing rapidly.
Broader Context: Aligning Policy, Planning, and Operations
Viewed together, the MISO PAC discussions reinforced themes raised in MISO’s large load workshops: clarity, precision, and alignment matter more than ever. As large loads become central drivers of transmission needs, ambiguous assumptions around rights, capacity, or operational behavior can quickly translate into reliability or cost allocation challenges.
The Attachment GGG updates aim to remove gray areas around what is — and is not — being requested through the interconnection process. ZGIAs offer a targeted tool to recognize modern load configurations. And the scrutiny applied to the GI Workbook highlights the importance of disciplined data governance in an environment where small modeling changes can have outsized impacts.
Takeaways
The January MISO PAC meeting reflects a necessary tightening of interconnection and planning frameworks in response to real system stress. The push to clearly separate connection from deliverability rights, limit study scope, and formalize temporary operating options aligns with the physical realities highlighted in recent large load discussions.
ZEG sees particular value in MISO’s treatment of ZGIAs as a defined, reliability-aware mechanism rather than an informal workaround. As on-site generation becomes more common for large loads, especially data centers, clearly modeling how these resources behave — and just as importantly, how they do not behave — will be essential to maintaining system stability.
At the same time, stakeholder concerns around the GI Workbook illustrate how quickly planning assumptions can drift if corrections, forecasts, and project statuses are not tightly controlled. In a system facing both rapid load growth and evolving resource mixes, precision in inputs is not an administrative detail — it is a reliability requirement.
Understanding MISO Requests
As MISO refines Attachment GGG, expands the use of ZGIAs, and incorporates updated planning inputs, early technical clarity is becoming a decisive advantage for large load projects. Understanding exactly what rights are being requested, how on-site generation will be treated, and how projects will appear in planning models can materially affect timelines, costs, and long-term operability.
ZEG experts work with developers, utilities, and infrastructure owners to evaluate large load and interconnection strategies before policy ambiguity or modeling assumptions create downstream risk. Through detailed transmission analysis, interconnection diligence, and system performance assessment, contact us to help you align your project design with MISO’s evolving requirements while protecting speed-to-power objectives.
For organizations navigating MISO’s large-load and interconnection landscape, proactive technical analysis can reduce uncertainty, strengthen regulatory positioning, and support more reliable project execution as policy frameworks continue to evolve.
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Access More Summaries from MISO this month:
MISO Large Load Additions Workshop: Technical Takeaways and Grid Implications (January 30, 2026)
