MISO official tells Minnesota committee transmission upgrades, data‑center demand and interconnection backlogs are top reliability challenges

Brian Tullow, MISO’s executive director for external affairs in the North Region, told the Minnesota House Committee on Energy Finance and Policy that the Midcontinent Independent System Operator is focused on maintaining reliability and affordability as the grid adds variable renewable generation and new large, continuous loads such as data centers.

Tullow described MISO’s role as an independent, not‑for‑profit regional transmission organization that dispatches generation based on short‑run marginal cost and manages a wholesale market that resets every five minutes. He emphasized that MISO does not own generation or distribution assets; member utilities retain ownership and must still complete state permitting and siting for transmission projects assigned to them after MISO’s regional planning approvals.

Key points Tullow presented:

- MISO’s footprint covers roughly 15–20% of U.S. load and includes multiple states; it recorded a new wind output record of about 10.5 gigawatts during a recent cold, clear day. - Long‑range transmission planning: MISO approved an earlier portfolio (Tranche 1) of regional projects (about $10 billion) and in December its board approved a larger portfolio (Tranche 2.1) with an estimated price tag near $20 billion; MISO projects a benefit‑to‑cost ratio in the range of about 2–3 for that work. - Interconnection queue backlog: developers have requested very large amounts of capacity (Tullow cited queue volumes in the hundreds of gigawatts), and many projects are waiting for transmission upgrades before they can be interconnected. MISO’s transmission tranches aim to unlock access for those projects. - Data‑center demand: data centers present new 24/7 loads that can be large and sited in parts of the grid that are thin on transmission; Tullow said adding generation and transmission faster than ever will be necessary to accommodate fast‑moving load additions while protecting consumers. He said data centers generally resist interruptions and sometimes bring onsite backup generation; MISO encourages grid‑connected backup and any flexibility on the load side. - Market dispatch and costs: MISO conducts an economic dispatch that considers short‑run marginal costs only; renewables and nuclear typically set low marginal costs (renewables often near zero), while gas and coal frequently determine marginal prices depending on commodity markets and pipeline constraints. - Reliability scenarios: Tullow highlighted multi‑day and multi‑hour “wind droughts” (periods with little wind generation) as planning scenarios that require dispatchable or long‑duration resources and reserves. - Cybersecurity and geomagnetic risk: MISO devotes substantial staff resources to cybersecurity and monitors space weather to prepare for geomagnetic disturbances; Tullow said the organization has been successful to date in defending systems but described geomagnetic events and EMPs as high‑impact risks that require monitoring and preparedness. - Tools and alternatives: Tullow supported non‑transmission options such as demand response, virtual power plants, batteries and grid‑enhancing technologies as useful pieces of the overall solution, but said most transmission owners must evaluate and implement those options locally.

Committee members asked about congestion costs, how MISO accounts for environmental externalities (Tullow said MISO’s dispatch does not incorporate externalities, only short‑run marginal cost), how interconnection queue management differs from other regions (ERCOT’s single‑state model differs materially), and where value from RTO membership accrues to consumers (MISO estimates billions in benefits and reserve sharing advantages). Tullow also pointed committee members to MISO’s public data on misoenergy.org.

The briefing underscored tensions between rapid load growth in parts of the footprint, long lead times for high‑voltage transmission projects, and the need to maintain reliability via a diversified portfolio, market design adjustments and grid upgrades. Members requested further briefings and indicated bills on related topics may follow.