Data Center Site Selection in MISO

The Midcontinent Independent System Operator (MISO) runs the transmission system and wholesale market for all or parts of Arkansas, Illinois, Indiana, Iowa, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Montana, North Dakota, South Dakota, Texas and Wisconsin, plus Manitoba in Canada. It is part of the Eastern Interconnection and is regulated by FERC for its U.S. operations.

The footprint is often discussed in two broad parts: a northern and central area across the Upper Midwest and Great Lakes, and a southern area reaching to the Gulf Coast. They are connected but have different generation mixes, climates and transmission links. Within both, service comes from investor-owned utilities, cooperatives and municipal utilities. For the general role of RTOs, see our guide to ISO and RTO markets.

Most of MISO’s states kept vertically integrated utilities. The utility owns or contracts for generation, owns transmission and distribution, and sells bundled service at rates set by the state utility commission. A few states allow limited retail choice. For most data center sites in MISO, the local utility is both the connection provider and the energy supplier.

That has practical effects. Large-load terms come through the utility’s tariffs and special contracts, approved by state regulators. New generation to serve a large load usually goes through the utility’s resource planning and state review. A utility that wants the load can be an active partner, while one that is cautious can slow everything down. See large-load tariffs and electric service agreements.

In MISO, utilities and their state regulators carry the main responsibility for having enough generation. MISO sets reserve requirements and runs an annual Planning Resource Auction that lets load-serving entities meet or balance their obligations. Many utilities meet most of their needs through their own plants and contracts, using the auction at the margin.

A large new load changes a utility’s resource plan. The utility may need new generation, longer life for existing plants or new contracts, and those choices often need state approval. That can add time, and it can lead the utility to ask the data center for long-term commitments, minimum bills or help funding new resources. Asking early how the utility would supply the load, not just connect it, is one of the most useful steps in MISO.

A data center applies to the local utility or transmission owner, which studies the connection and coordinates with MISO on transmission effects. MISO’s regional planning process includes forecast loads and can identify upgrades. As in other regions, loads do not use the generator queue, though any grid-connected on-site generation may.

• The utility’s process sets the steps, deposits and expected timelines.
• Upgrade costs may fall to the customer, the utility’s ratepayers or a regional allocation, depending on the upgrade and the applicable tariff.
• Utilities may tie service to an approved resource plan for the new load.
• Cooperatives often rely on a generation and transmission cooperative for supply, which adds a party to the conversation.

MISO borders PJM to the east and SPP to the west, and the borders are irregular. In some states, neighboring counties, or even neighboring tracts, are served by utilities in different RTOs. Transmission flows across these seams, and upgrades on one side can depend on studies on the other.

For a site near a seam, confirm the serving utility and its RTO early. A line visible from the property may belong to a different system than the one that would serve the load. Our guides to PJM and SPP cover the neighboring regions.

• Climate. Northern areas have cool climates that support efficient cooling and lower design PUE. Southern areas are hot and humid for much of the year.
• Water. The Great Lakes and major rivers provide significant water resources, but withdrawals from the Great Lakes basin are governed by an interstate compact and state rules, and local supply varies.
• Hazards. Southern areas carry hurricane, flood and storm surge exposure. The central footprint has tornado and severe storm risk, and parts of the Mississippi Valley have seismic and river flood exposure.
• Land. Much of the footprint is agricultural, with large, flat tracts. Converting farmland can raise local concerns and, in some states, specific review. Check any state farmland preservation programs, drainage district obligations and easements that run with the land.
• Fiber. Metro areas and interstate corridors have good fiber; rural sites may need long laterals for diverse routes.

1. 01Identify the serving utility, its RTO and whether the site sits near a seam with PJM or SPP.
2. 02Ask how the utility would supply the load, not just connect it, and whether new generation needs state approval.
3. 03Learn the utility’s large-load tariff, contract terms and required commitments.
4. 04Map nearby transmission and substations and ask about pending large loads.
5. 05Check water supply and any basin or state withdrawal rules.
6. 06Screen for flood, storm and seismic exposure, especially in the south and along major rivers.
7. 07Confirm local zoning and fiber options.

When we screen sites in MISO, the utility conversation tends to set the timeline more than the transmission map does.