A Longer Minimum Term and a Lower Threshold: The Wisconsin Commission's Preliminary Decision on a Very Large Customer Tariff

On April 24, 2026, the Public Service Commission of Wisconsin said in a release that it "today took up" one utility's "Very Large Customer (VLC) and Bespoke Resources Tariff application," and that it "made major modifications to improve the tariff." The application, the release says, came in March 2025 "in response to large data center customers entering the utility's service territory." The release's own headline calls it a data center tariff. The release calls itself "an overview of the preliminary decision(s) verbally made in the Public Service Commission's open meeting," and says the final order "is the official action of the Commission."

What a Tariff Sets

A utility tariff, the release explains, sets the rates, terms and conditions on which a utility serves customers in its territory. A utility that wants a new one needs the commission's approval, because the commission regulates the state's electric, gas and water utilities. It also says what it does not do. "The Commission does not regulate the permitting, construction, or operations of data center facilities."

A Longer Term and a Lower Threshold

The commission gives what it calls "a non-exhaustive list of actions taken to strengthen protections" for the utility's existing customers "and increase transparency and visibility." "The Commission extended the VLC tariff minimum initial term length to 15 years," the release says, and it adds that the change "prevents cost-shifting to existing customers." It also lowered the demand threshold for eligibility from 500 MW to 100 MW. That, in the commission's words, "expands tariff applicability to smaller data centers, which further shields existing customers from data center-related costs."

A lower threshold brings smaller campuses under the same conditions, the longer minimum term among them. A developer sizing a campus in that territory meets those terms at a smaller size than before the change.

Who Pays for Generation and Transmission

On generating facilities, the commission "removed a capacity-only option that would have allowed data centers to only pay for 75% of the costs of generating facilities." The removal of that option and the approval of what the release calls the Full-Benefits resource model, it says, "protects existing customers by requiring the VLCs to pay 100% of their costs." On the wires, it "required tariff revisions to address the risk of transmission cost shifting from data center customers to existing customers." The release does not say what those revisions are. It also ordered more reporting, on how the tariffs work in practice and on agreements between the utility and its very large customers, and it created "a mechanism for the Commission to make future adjustments if needed."

The Order to Come

None of this is the order itself. The commission's final order "will be posted to ERF in the coming weeks once it's available," the release says, ERF being its "Electronic Records Filing (ERF) System." Its disclaimer says of the summary, "This document is not intended to modify, supplement, or be a substitute for the Commission's orders."