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MISO interconnection

Midcontinent ISO studies generator interconnection requests through its regional process, including the Definitive Planning Phase for applicable projects.

Guide updated October 9, 2026.

Identify the study path and cycle​

MISO's Definitive Planning Phase (DPP) includes three study phases and two decision points before agreement work. The governing framework is Tariff Attachment X, supported by MISO's generator-interconnection procedures and business-practice material. Determine the applicable cycle and service request before committing to a submission schedule. Studies and procedures

MISO directs customers to its Generation Interconnection Application (GIA) Portal through the MISO Help Center. Use the portal access instructions linked on the official page, including the appropriate customer account type. Special paths, such as an applicable expedited resource-adequacy study, have separate eligibility and submission rules. Generator interconnection

Prepare the application inputs​

Build the submission around the current Appendix 1 application, technical attachments, and portal fields. MISO's preparation materials identify technical milestones, payments, site evidence, and additional documentation for shared facilities. Prepare to apply

For an orderly preparation workflow, maintain these information groups:

  • Company identity, contacts, requested service, and the project's selected cycle.
  • Technology, unit counts, facility capacity, export assumptions, and energy-storage operating modes.
  • Point of interconnection, transmission-owner interface, geographic location, and voltage.
  • Requested project dates and the schedule supporting those dates.
  • Current application attachments, equipment data, drawings, and payment records.
  • Shared-interconnection-facility arrangements and supporting agreements where applicable.

Assign an owner to each missing input. Make the difference between an unanswered required field, an item that does not apply, and an engineering assumption visible to the reviewer.

Organize the technical package​

The application should tell the same engineering story as the model package. Use a common equipment register for the generating units, inverters, transformers, collector system, plant controls, and interconnection facilities. Confirm the current model formats, software versions, and study-stage deliverables with MISO and the relevant transmission owner.

As a preparation practice, retain model documentation alongside source data: supplier revisions, parameter units and bases, operating limits, aggregation choices, and any test cases. Drawings should identify the proposed interface and equipment clearly enough for the study team to relate them to the submitted data.

For storage, keep injection capability, charging demand, energy capacity, and operating assumptions distinct. For mixed technologies, explain what is shared and what is controlled independently. Use MISO's study resources to locate the material relevant to the current stage.

Manage site control and deposits​

MISO identifies application fees, study funding, and milestone obligations separately. Their timing and treatment depend on the applicable process and current tariff. Use the official fee postings and cycle instructions rather than an amount copied from an older project. Application and milestone resources

For internal tracking, separate plant-site evidence from interconnection-facility and tie-line evidence. Map each parcel or route segment to the relevant document, term, and unresolved issue. Track cash deposits, letters of credit, invoices, and later adjustments as separate records with clear acknowledgement status.

Review each decision point​

Recommended package checks before submission or a decision point include:

  1. Compare requested service and capacity with the latest model and one-line revision.
  2. Confirm that revised equipment has been carried into all dependent exhibits.
  3. Reconcile the site layout, legal descriptions, and proposed route.
  4. Log every deficiency response, its supporting attachment, and whether it has been accepted.
  5. Record the decision, financial action, and evidence of completion for the next stage.

Interconnection and market registration are distinct workstreams. MISO publishes separate market-participation registration information for organizations preparing to participate in its markets.

Official sources and scope​

Use generator interconnection for current application resources, GI studies for process material, and market participation for the later registration workstream.

This guide supports preparation and navigation. The effective tariff, current cycle instructions, and project-specific transmission-owner requirements control. A completed checklist does not establish application acceptance or compliance.