PSC finds a $441 million data-center cost shift onto other customers

The Wisconsin Public Service Commission told federal regulators on August 14 that current grid rules would move $441 million of one data center’s power-line costs onto other wholesale customers, even if the data center uses every megawatt it asked for.

A reliability project is billed to the whole pricing zone

ATC, the transmission-only company whose lines carry power across Wisconsin and the Upper Peninsula, filed agreements at FERC on July 24 covering more than $500 million of upgrades to connect Microsoft’s campus in Mount Pleasant, the four projects in the agreements.^{6, 10} PSC staff testified in February that the customer’s full load “requires $1.4 billion in new transmission facilities,” and the PSC told FERC it has permitted “numerous projects” for this load that the agreements do not cover.¹

Under ATC’s rate those upgrades roll into the zonal rate that every wholesale customer in ATC’s zone pays by its share of load.¹ We Energies passes its share to Microsoft through a transmission charge with a minimum demand charge, under the data-center tariff the PSC voted on April 24 and finalized on May 21, 2026.^{7, 1}

A reliability project is billed the same way. When MISO’s planners find that a new load pushes the grid past a reliability standard, the fix is filed as a “baseline reliability project,” and MISO charges 100 percent of it to the local pricing zone.⁴ In ATC’s zone that is every customer of every utility ATC serves.

MariBell and BECI fall under a third rule. MISO’s board approved them on December 12, 2024 inside the $21.8 billion Tranche 2.1 portfolio, whose cost is shared across MISO’s Midwest subregion in proportion to each utility’s energy use.^{8, 9} PSC staff put Wisconsin providers’ first-year charge for the Tranche 2.1 projects at $379.29 million if the projects are approved.⁹

The PSC found a $441 million cost shift

On June 18, 2026, FERC ordered MISO to show why its tariff is just and reasonable without public information on the network-upgrade costs of large loads and without a standard cost-recovery agreement to stop cost shifting, or to propose the tariff changes that would fix it.⁵ MISO asked for more time under the order’s abeyance option. With it, MISO’s answer is expected in mid-November.^{3, 5}

The PSC intervened on July 31 and filed comments on August 14 over the signature of its chief legal counsel, Cara Coburn Faris.¹ The comments run 11 pages, plus 164 pages of attachments from the We Energies data-center tariff case, docket 6630-TE-113. The two tables that matter are both on page 4, and they began as testimony that PSC staff witness William Koebel filed on February 10, 2026.¹ Staff compared the customer’s zonal-rate payments at full load with its directly assignable costs. Over 45 years the gap, in present value, is $441 million, which the PSC called “a $441 million cost shift to ATC’s other wholesale customers.”¹ A second staff table puts the extra cost to We Energies’ own other customers at $210.8 million over the same period.¹

On page 2 the PSC wrote that “‘Speed to Power’ must not be used as an excuse to turn a blind eye to cost causation principles that provide critical consumer protection.”¹ On page 3: “large load customers simply cannot be made responsible for the costs they cause to the system without stronger Commission action on this front.”¹

The PSC still backed accepting ATC’s agreements as “an improvement upon the status quo,” and urged FERC to make them effective July 1, 2026, so that “over $39 million in financing costs” stops spreading to ATC’s other customers.¹ It wrote that it does not advocate direct assignment and takes no position on whether the deal is fair to other customers.¹ It asked FERC to keep every issue in the June investigation open and to order reporting that compares each large load’s cost with the zonal rate in dollars per megawatt.¹ It also wrote that the deal cannot be judged without a “clear, comprehensive list” of the upgrades the load needs, which ATC does not publish, and that MISO’s own study found eight projects for this customer while the agreements cover four.¹

The Citizens Utility Board, the state’s ratepayer advocate, filed on August 21. It also calls the agreements an improvement, and it asked FERC to find them “unjust and unreasonable as proposed” because they lack ways to stop cost shifting. In CUB’s words, ATC’s zonal rates “would thus under-recover the incremental costs associated with large loads.”² Microsoft protested too. It said the agreements should be adjusted so it pays the costs it actually causes, and asked FERC to send the deal to a settlement judge or reject it.⁶ FERC has not ruled, and the filing was not on its September 10 meeting agenda.¹²

Reliability lines driven by data centers are billed to whole zones

At MISO’s Large Load Working Group on September 9, the reliability-project bill came up. Anthony Alvarez of the Iowa Office of Consumer Advocate said reliability projects spurred by large loads “are not being tracked back” to the loads that caused them.³ Natalie McIntire of the Sustainable FERC Project said projects “over a billion dollars” are “being categorized as ‘local reliability’ but are being driven by large loads.”³

MISO had approved 82 expedited project requests in its 2026 plan as of early September.³ RTO Insider pointed to Entergy’s nearly $1.5 billion 500 kV line and switching station in northern Louisiana, under development because of Meta’s Hyperion campus in Richland Parish.³ MISO said it will take up cost shifting of network upgrades on September 23, and Bill Booth, a consultant to the Mississippi commission, said MISO seemed to be “punting” the reliability-project question into October.³

Marcus Hawkins, one of Wisconsin’s three PSC commissioners, told the Organization of MISO States on September 10 that the issue “is just sort of being pushed to the side,” and he asked the state regulators’ group to write a position paper on transparency and cost-shifting guardrails.³

Neither line is in these dockets

None of the FERC or MISO filings above names MariBell or BECI. Both were approved inside the Tranche 2.1 portfolio on a regional need case in December 2024, and the September 9 debate concerned local reliability lines like the one in Louisiana.^{3, 8} We have found no public document that ties either 765 kV line to a specific data center.

The PSC’s draft state energy plan, open for comment until September 28, states two separate facts: 72 percent of Wisconsin’s forecast peak-demand increase comes from three data-center developments, and BECI is among the transmission the state expects.⁹ Our comment guide asks the PSC to add what the draft leaves out: label each large load by stage, from proposed to operating, and say who pays for transmission built around a load that is delayed or cancelled.

What you can do

Comment on the draft Strategic Energy Assessment in docket 5-ES-113 by Monday, September 28. Our guide gives the PSC’s form, the report pages to cite (2, 10 and 79), and a sample comment to rewrite in your own words. Cite the PSC’s own August 14 filing at FERC, docket ER26-3265, pages 2 to 5.

MISO’s Large Load Working Group meets by WebEx on September 23, and the join details are on its event page.¹¹

Legal note. This post describes public filings and a public comment process. A comment in docket 5-ES-113 becomes a public record and does not make the writer a party to any case. General information, not legal advice.