The Federal Energy Regulatory Commission Orders MISO to Clarify Rules for Including Advanced-Stage Merchant Transmission Projects in Regional Transmission Planning

In its October 16, 2025 open meeting, the Federal Energy Regulatory Commission (FERC) took action on a number of matters, including Invenergy Transmission LLC v. Midcontinent Independent System Operator, Inc. Invenergy Transmission’s complaint alleged that MISO’s tariff and transmission planning processes fail to provide a clear and transparent method to incorporate advanced-stage merchant high voltage direct current (MHVDC) transmission projects, like the Grain Belt Express Line, into MISO’s regional planning process. The Commission agreed that MISO’s tariff lacked specificity on when and how MHVDC transmission projects are incorporated into its transmission planning models and directed MISO to submit revisions to its tariff within 90 days to clarify the process. The Commission declined, however, to grant Invenergy Transmission’s request to require the immediate inclusion of the Grain Belt Express Line in MISO’s existing Long Range Transmission Planning base case models, finding that Invenergy Transmission did not demonstrate that MISO failed to follow its current tariff and business practice manuals. Commissioner See issued a concurring opinion emphasizing the importance of clear tariff provisions and the investment confidence that can be gained by performing sensitivity analyses for late-stage merchant transmission projects like the Grain Belt Express Line.

Other matters acted on in FERC’s October 2025 meeting are summarized here and include a Notice of Proposed Rulemaking seeking comment on Standards for Business Practices of Interstate Natural Gas Pipelines.