Common Questions

What states does MISO cover?

MISO (Midcontinent Independent System Operator) covers 15 US states stretching from Manitoba, Canada in the north to Louisiana in the south, including major data-centre markets in Illinois, Indiana, and Ohio.

What did FERC order MISO to do about large-load interconnection in June 2026?

FERC issued MISO a Section 206 show-cause order on 18 June 2026, directing it to justify or reform its large-load tariffs across five categories including co-location terms and study processes. MISO must respond by 17 August 2026.Source: FERC

When must MISO submit its generation-adequacy report to FERC?

MISO must file its generation-adequacy report by 20 July 2026 under FERC's RM26-4-000 docket, the same proceeding covering all six US RTOs, ahead of its 17 August show-cause response.Source: FERC

Background

FERC issued MISO a Section 206 show-cause order on 18 June 2026 alongside all five other US Regional Transmission Organisations, directing it to justify or reform its large-load tariffs across five areas including co-location terms, study processes, and cost allocation. The same RM26-4-000 docket also requires MISO to file a generation-adequacy report by 20 July 2026, ahead of its show-cause response. Responses are due 17 August 2026, public comments 16 September, and any binding federal standard falls to 2027 at the earliest.

MISO (Midcontinent Independent System Operator) manages the high-voltage transmission grid across 15 US states stretching from Manitoba to Louisiana, covering a region that includes major data-centre growth markets in Illinois, Indiana, and Ohio. MISO operates in two electrically separate interconnection regions (North and South), creating operational complexity for large-load integration. It manages one of the largest footprints of any US RTO by land area and administers wholesale electricity markets for more than 180 million customers.

MISO's large-load queue is a significant reform target because the Midwest corridor offers lower land costs, simpler permitting, and access to nuclear and renewable generation capacity that Northern Virginia and Texas cannot match on speed or carbon profile. FERC's show-cause process, alongside the parallel generation-adequacy filing, will determine whether MISO must harmonise its study timelines and co-location terms with the other five RTOs, or whether it can develop Midwest-specific rules that reflect its distinct generation mix and two-region structure.