The Midcontinent Independent System Operator on Oct. 2, 2026, filed tariff revisions at the Federal Energy Regulatory Commission that would create a Large Load Addition Resource Study, or LARS: an expedited process for studying new loads of 200 MW or greater together with electrically proximate new generation. According to MISO's transmittal letter in Docket ER27-25-000, filed under Federal Power Act section 205, the load and generation would be studied in a parallel process of approximately 120 days. MISO asked for a Dec. 2, 2026 effective date so it can open the first LARS study period in the first quarter of 2027.

The filing is supported by testimony from Christina Drake, MISO's Director—Generation Interconnection. MISO said LARS responds to FERC's June 18, 2026 show-cause order in Docket EL26-70-000, and described it as a standalone process that complements two other MISO proposals pending at FERC when LARS was filed: the Zero Injection Generator Interconnection Agreement (ZGIA) filing in ER26-3552 and the Interconnection Reliability Requirement filing for large loads in ER26-3650.

How the Proposed Process Would Work

LARS pairs a large load with new generation and studies the two at the same time. The filed design sets these terms:

  • Threshold: loads of at least 200 MW.
  • Capacity: three study periods per year, with ten applications accepted per period, assigned in order of time-stamped submission.
  • Fee: a $250,000 non-refundable deposit with each application, paid by the party the tariff calls the LARS Associated Transmission Customer.
  • Pre-submission step: mandatory coordination before an application is filed, in which the prospective generator and the Transmission Owner must agree on a point of interconnection.
  • Pairing commitment: an executed agreement of at least five years showing the generator's output will serve the load.
  • Timing limits: the generator's commercial operation date and the load's in-service date can be no later than three years from the date the application is submitted.
  • Withdrawal: if either the load or the generation portion withdraws after the study is completed, the resulting Large Load Generator Interconnection Agreement (LLGIA) is void, non-refundable deposits are forfeited, and there is no restudy.

Why 200 MW

MISO's threshold moved during the stakeholder process. The transmittal letter says MISO initially proposed 250 MW because recent Expedited Project Review results showed meaningful grid impacts from loads of 250 MW and greater, with upgrades becoming increasingly likely between 300 and 500 MW and consistently necessary at 1,200 MW and above. MISO said stakeholders proposed alternatives including 200 MW, which it adopted as it expanded LARS beyond hyperscale load to other large loads, including industrial loads.

That debate played out in the Large Load Working Group. MISO brought a draft LARS design and tariff language to the group's Aug. 27, 2026 meeting, with written feedback due Sept. 10, according to the stakeholder feedback page for item LLWG-2026-6. The draft set a 250-MW minimum, capped generator Interconnection Service at 150% of the load's peak demand, allowed ten paired projects per cycle and three years from application to commercial operation, and required the generator and load to sit in the same Local Resource Zone. MidAmerican Energy urged a 200-MW threshold, and Alliant Energy asked for 200 MW or less.

What Stakeholders Said

Written comments on the draft split along several lines:

  • Project cap: Entergy supported LARS but asked MISO to remove the ten-project cap.
  • Timeline: Duke Energy Indiana asked MISO to extend the three-year commercial operation limit, writing that "even shovel ready projects will require up to 6 years from development to in-service" and that three years is not achievable today for natural gas units or battery storage.
  • Scope and duration: The Organization of MISO States' transmission planning and resources work groups supported limiting LARS to high-impact loads and adding a five-year sunset.
  • Study design: Clean Grid Alliance opposed LARS as a parallel process that could miss combined effects with projects in MISO's regular interconnection queue, and environmental-sector commenters urged MISO to "further develop the GALIP proposal and abandon the LARS proposal." Both preferred GALIP, a streamlined generator and load interconnection proposal.
  • Pairing geography: The Minnesota Department of Commerce and the Citizens Utility Boards of Wisconsin and Michigan recommended binding LARS to an "electrically proximate" definition, saying the zone-wide approach "could considerably increase congestion across an LRZ."

The filed version kept the ten-applications-per-period structure, the three-year limit, the $250,000 fee and the 150% cap. It also kept the Local Resource Zone as the geographic anchor: MISO wrote that "anchoring the proximate requirement with the LRZ is more efficient and effective" because it aligns with its resource adequacy construct, and that allowing LARS generators to connect at multiple points provides a "proximate plus" solution.

Who Has Intervened

By Oct. 20, 2026, 29 parties had filed motions or notices to intervene in the ER27-25 docket, according to FERC's eLibrary. They include generators and developers (Constellation Energy Generation, Vistra, NextEra Energy Resources, EDF Power Solutions and Enchanted Rock), utilities (Entergy, American Electric Power Service Corp., Alliant Energy, DTE Electric and Ameren Missouri), state regulators and consumer advocates (the Mississippi and Michigan public service commissions, the Minnesota Department of Commerce, the Iowa Office of Consumer Advocate and the Citizens Utility Boards of Michigan and Wisconsin), and industry and advocacy groups including the Coalition of MISO Transmission Customers, Clean Grid Alliance, the Solar Energy Industries Association, the Natural Resources Defense Council and Fresh Energy.

Context: MISO's Load Outlook

In the transmittal letter, MISO said that after demand grew about 0.5% a year from 2009 to 2024, it now projects annual load growth of approximately 1% to 3% through 2044, driven in part by energy-intensive loads such as data centers and manufacturing expansion. MISO also said LARS is one piece of a broader large-load framework developed through the Large Load Working Group, and that additional initiatives addressing the show-cause order will be presented to FERC in separate section 205 filings by Nov. 16, 2026.

What Happens Next

Comments on the LARS filing are due at 5 p.m. Eastern on Oct. 23, 2026, according to FERC's combined notice of filings. As of Oct. 20, FERC had not issued an order in Docket ER27-25; MISO asked the commission to act by the Dec. 2 requested effective date. MISO has said it will file its remaining large-load proposals with FERC by Nov. 16, 2026.

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