ATC owns and operates high-voltage transmission lines in Wisconsin and Michigan, planning, building, maintaining, and operating the regional electric grid to move power from generators to homes and businesses. It works by planning transmission routes, constructing and maintaining lines, and running the grid with engineers and technicians to ensure steady power delivery; revenue comes from charging for transmission services. Compared with competitors, ATC focuses on regional transmission ownership and operation within its two-state footprint and combines grid stewardship with STEM education and community engagement while pursuing efficiency and technology improvements. Its goal is to maintain a reliable, resilient grid, adapt to changing energy needs, and provide safe, affordable power while advancing grid innovations through its workforce and community initiatives.
Company Size
501-1,000
Company Stage
Debt Financing
Total Funding
$250M
Headquarters
City of Pewaukee, Wisconsin
Founded
N/A
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ATC reapplies to build a more than $2B transmission project serving Port Washington data center. Project could cost nearly $2.5B to $2.7B September 18, 2026 Updated September 18, 2026 at 5:58 am After regulators told them to go back to the drawing board last month, American Transmission Co. has reapplied to build a more than $2 billion transmission project that will serve the data center being built in Port Washington. The utility filed a new application this week with the Public Service Commission of Wisconsin, or PSC, to build the Ozaukee County Distribution Interconnection Project. It would include new and rebuilt high-voltage power lines, upgrades to existing facilities and construction of up to five new substations. The project would extend across Fond du Lac, Calumet, Manitowoc, Ozaukee, Sheboygan and Washington counties. It would serve Oracle's data center campus in Port Washington. Understanding Wisconsin, together. WPR's "Wisconsin Today" newsletter keeps you connected to the state you love without feeling overwhelmed. No paywall. No agenda. No corporate filter. American Transmission Co., or ATC, had to file the new application after the PSC last month unanimously voted to revoke a "completeness" determination for the company's previous application to build the project. Regulators felt the application had seen such extensive revisions that it became difficult for officials and the public to adequately review. It was a rare move for the utility regulator. Both ATC and a ratepayer watchdog said it was the first time they'd seen the commission revoke a completeness determination in recent decades, if ever. ATC declined to provide an interview about the new application. In a statement, Jared Winters, executive vice president and chief assets officer for ATC, said the company "substantially improved" its application since its last filing and made changes based on feedback from the commission and public. He said that resulted in an updated project design and power line routes. "The revised route configuration reflects additional feedback, analysis and routing and siting work, and we believe it represents the most responsible, buildable and electrically sound option for serving this significant new electric demand," Winters stated. "We appreciate the input we've received and will continue that engagement as the PSCW review process moves forward." According to the application, the project would cost between $2.48 billion and $2.72 billion. Tom Content, executive director of the Citizens Utility Board of Wisconsin, said the project could be the most expensive single transmission project that he's seen in Wisconsin. He said the large price tag underscores the massive energy needs of Oracle's data center campus, which is expected to need 1,300 megawatts in its first phase and up to 3,500 megawatts in the future. "Frankly, We Energies' largest customer today is less than 100 megawatts, and, at the max, this could be 3,500 - it's like putting 35 steel mills onto the farm fields just north of Port Washington," Content said. "It takes eye-popping numbers like this to make people go, 'Wow, this is really massive, and our energy world is changing dramatically.'" Of the more than $2 billion price tag, the application says roughly $1.1 billion is associated with a system built at a substation in Decker to help stabilize the grid and manage large and shifting electricity demand from Oracle's data center. The application says Oracle will fund that system and "no costs" related to it "will be paid by other customers." Content said energy demand from data centers can vary at different times of day, and fluctuating power flows from data centers have caused reliability concerns in states like Virginia and Texas. The system the regulatory filing says Oracle will pay for is meant to address that issue, Content said. But whether the tech company ends up covering the more than $1 billion cost, he says, will be up to federal energy regulators who set transmission rates. "Our overarching concern for Wisconsin customers is whether data centers will actually be billed correctly and accurately and completely for costs linked to data centers," Content said. "It's up to the feds, the Federal Energy Regulatory Commission, to do that." Wisconsin Public Radio, (C) Copyright 2026, Board of Regents of the University of Wisconsin System and Wisconsin Educational Communications Board.
American Transmission Co. Data Center issues. * August 16, 2026 Current cases: CUB is working to ensure tech companies pay their way so homeowners, renters and small businesses aren't left holding the bag for power plants that ultimately might not be needed. CUB seeks safeguards to protect customers from the significant risks involved with the AI data center boom. Power Line Projects for Data Centers: American Transmission Co. (ATC) has multiple transmission line projects in the works to serve data centers in Wisconsin, including two projects for the Racine County data center, one for the Beaver Dam data center, and an extremely large project for the Port Washington data center. Customers of Wisconsin and upper Michigan utilities already paid for projects to serve the Racine Microsoft data center project. ATC built a line specifically for Foxconn but their major investment in Wisconsin did not pan out. CUB does not typically weigh in on routing and siting decisions for big power-line projects. Its main concern is to ensure that utilities prove their proposals are needed and cost-effective. With respect to data centers, CUB is greatly concerned that more than $2 billion of ATC power-line projects will fall on the backs of homeowners, renters and small businesses - and not on tech companies. In August 2026 the PSC revoked the completeness determination for this project, essentially requiring ATC to start over on development of a project estimated to cost about $1.5 billion. This unusual and unprecedented move by the PSC occurred because many key elements of the project had changed so significantly since December 2025 when a completeness determination was first issued for the project. News and Commentary: PSC Case Filings: Protecting Customers from Data Center Costs: One issue that was not resolved completely by the PSC is how to collect the costs of big new transmission lines needed for data centers. Will customers be on the hook for more than $2 billion of power line projects for data centers? Under current rules, transmission cost cannot be directly assigned to a data center. This is being discussed in multiple forums at the state level as well as at the Federal Energy Regulatory Commission. Earliest this year, executives from seven tech companies, including four actively involved in data center development in Wisconsin, signed the Ratepayer Protection Pledge at the White House. This non-binding pledge promises to insulate customers from data center costs, including for "network upgrades," or transmission projects. FERC has ordered the regional grid operator for the Midcontinent region to demonstrate how tech companies are being assigned costs for transmission lines. Watch this space for updates. News and Commentary:
Wisconsin regulators send ATC back to the drawing board on data center connection project. By Paul Kieffer - Wisconsin Watch August 7, 2026 Get Our Email Newsletter Local news about the companies, people and issues that impact business in Northeast Wisconsin and beyond. Wisconsin regulators voted Thursday to send the American Transmission Company (ATC) back to the drawing board as the utility attempts to build the grid infrastructure needed to plug in the Port Washington data center. Public Service Commission (PSC) Chair Summer Strand called the move a "reasonable reset" after ATC repeatedly adjusted the project's design, which commission staff and ratepayer advocates argued left both regulators and the public with a muddy picture of a grid expansion expected to cost well over $1 billion. ATC and its partners, however, warned the decision - likely the first of its kind for the century-old commission - could set a dangerous precedent that drives away investment in Wisconsin's energy sector. Data center connection at risk. ATC, which owns and operates transmission lines in the eastern half of Wisconsin, is on the hook to connect the soon-to-open Port Washington data center to the electrical grid. The company approached the PSC last September for permission to break ground on the project as early as this past May. Its initial application outlined a more than $1.3 billion infrastructure package, including a high-voltage transmission line and five new substations spread across Fond du Lac, Ozaukee, Sheboygan and Washington counties, needed to "reliably serve" the new data center by December 2027. After two months of back-and-forth over the "completeness" of ATC's application, the commission took up the proposal in December 2025. ATC has since been vocal about the urgency of the infrastructure buildout needed to support the data center boom. The company is part of a coalition of utilities asking the Federal Energy Regulatory Commission (FERC) to speed up regional transmission projects needed to serve data centers by suspending competitive bidding, arguing that "bureaucratic red tape" presents a national security risk as the U.S. competes with China for "dominance" in the artificial intelligence race. Meanwhile, the utility has repeatedly adjusted its plans since December, redesigning proposed routes and adding a set of temporary bypass lines needed to avoid outages during construction. The PSC is responsible for reviewing those changes and giving other parties, namely ratepayer advocates and affected landowners, an opportunity to weigh in. Some commission staff sounded the alarm as the pile of revisions - and questions - grew. "I don't recall any other comparable cases in my experience with as many application material document revisions and ongoing design changes throughout the process," PSC Environmental Affairs Coordinator Adam Ingwell wrote in testimony filed last month. "The sheer volume of documents and revisions, without adequate explanation, likely makes it more challenging than typical for a member of the public to find specific information about the project." Those concerns reached Administrative Law Judge Michael Newmark, who criticized ATC for creating an "unreasonable burden" on commission staff and the public by scattering "a plethora of changes, modifications and updates" across six months of filings. ATC, on the other hand, cast the revisions as "routine." "Every application develops during review," the company's attorneys wrote on Wednesday. "Changes far larger and later than ATC's have never cast doubt" on whether an application should move forward, they added, citing a Barron County solar farm the PSC approved last March despite an "eleventh-hour" overhaul that included "relocating an entire substation." "There is simply no principled basis on which to treat ATC's lesser and earlier changes more harshly," the attorneys wrote. Ratepayer advocates weigh in. Ratepayer advocates generally avoid wading into fights over transmission line routes and substation siting, which Wisconsin Citizens Utility Board (CUB) Regulatory Affairs Director Corey Singletary described as a "zero-sum proposition" in which a victory for one group of landowners means shifting construction impacts onto another group of landowners. But CUB raised concerns that ATC's revisions make it difficult to forecast the project's cost. The route changes and new bypasses make the price tag "a moving target," said CUB Executive Director Tom Content, as does the possibility that ATC still attempts to complete the project by December 2027. "Would they be paying double overtime or triple overtime to build it that quickly?" The Wisconsin Utility Association itself weighed in on Wednesday to warn the PSC that any additional delays in the project will "lead to increased costs for customers." Transmission utilities generally pass along the costs of new infrastructure to ratepayers of all kinds via their electrical bills; We Energies, for instance, estimates that transmission-related costs account for about 10% of customers' bills. The PSC can't require ATC to assign project costs to the companies developing the Port Washington data center. Only FERC, the five-person federal regulator that oversees interstate transmission, could overhaul billing rules to fully shield other customers from the costs of new lines and substations needed to serve data centers. The commission offered an ad hoc solution this spring. The PSC's May order creating a new billing structure for We Energies' data center customers requires data center operators to pay a minimum transmission charge based on their projected electricity use. Wisconsin PSC Commissioner Kristi Nieto called the arrangement a "temporary stopgap measure" to protect other customers from the costs of overbuilt infrastructure if data centers use less electricity than anticipated. ATC and We Energies have since asked the PSC and FERC to approve a minimum transmission charge agreement with Microsoft, the operator of the vast new data center in Mount Pleasant. "This is a customer protection mechanism that follows the 'cost causer, cost payer' methodology," an ATC spokesperson wrote in an email to Wisconsin Watch. The utilities have not yet asked the commission to approve similar agreements with the companies developing the Port Washington facility: cloud computing giant Oracle, artificial intelligence firm OpenAI and data center developer Vantage. In testimony filed last month, Singletary urged the commission to enforce "cost containment" measures for ATC's project, including requiring the utility to cap its annual revenues from the new transmission lines. He also suggested that the commission push ATC to disclose any bids it receives for "work to be performed and equipment to be procured as part of this project," which he argued would help keep an eye on the company's efforts to rein in costs. 'Least-bad option' All three commissioners aired matching frustrations during a Thursday afternoon hearing on ATC's infrastructure plans before concurring on what Commissioner Marcus Hawkins called the "least-bad option" - requiring ATC to resubmit its application and restarting the case's 180-day clock. "There needs to be flexibility in the process," said Nieto, "but there also has to be some point at which the changes become significant enough that we need to evaluate whether we are still reviewing the same project that was originally proposed." "This PSC is not opposed or hostile to data centers, construction, generation, (or) transmission," Strand said, calling the decision "an unfortunate outcome." Nevertheless, she added, "this application represents a cautionary tale of when unrealistic and unreasonable speed-to-power expectations collide with a deliberative regulatory process." ATC has not indicated when it will resubmit its application as of Thursday afternoon, nor whether the December 2027 deadline is still within reach. "ATC is disappointed with today's Commission's decision and is considering its options," a company spokesperson wrote after the hearing. But the company's final filing before the hearing signaled the possibility of a legal fight. "To date, the Commission has processed the application consistent with the law," the company's attorneys wrote. "At this stage," restarting the process "would be the one action to depart from that."
Wisconsin regulators send ATC back to the drawing board on data center connection project. Wisconsin's Public Service Commission will require the state's largest transmission utility to restart the 6-month application to connect the Port Washington data center to the electrical grid. Aug 7, 2026, 11:52 AM CT Wisconsin regulators voted Thursday to send the American Transmission Company (ATC) back to the drawing board as the utility attempts to build the grid infrastructure needed to plug in the Port Washington data center. Public Service Commission (PSC) Chair Summer Strand called the move a "reasonable reset" after ATC repeatedly adjusted the project's design, which commission staff and ratepayer advocates argued left both regulators and the public with a muddy picture of a grid expansion expected to cost well over $1 billion. ATC and its partners, however, warned the decision - likely the first of its kind for the century-old commission - could set a dangerous precedent that drives away investment in Wisconsin's energy sector. Data center connection at risk. ATC, which owns and operates transmission lines in the eastern half of Wisconsin, is on the hook to connect the soon-to-open Port Washington data center to the electrical grid. The company approached the PSC last September for permission to break ground on the project as early as this past May. Its initial application outlined a more than $1.3 billion infrastructure package, including a high-voltage transmission line and five new substations spread across Fond du Lac, Ozaukee, Sheboygan and Washington counties, needed to "reliably serve" the new data center by December 2027. After two months of back-and-forth over the "completeness" of ATC's application, the commission took up the proposal in December 2025. ATC has since been vocal about the urgency of the infrastructure buildout needed to support the data center boom. The company is part of a coalition of utilities asking the Federal Energy Regulatory Commission (FERC) to speed up regional transmission projects needed to serve data centers by suspending competitive bidding, arguing that "bureaucratic red tape" presents a national security risk as the U.S. competes with China for "dominance" in the artificial intelligence race. Meanwhile, the utility has repeatedly adjusted its plans since December, redesigning proposed routes and adding a set of temporary bypass lines needed to avoid outages during construction. The PSC is responsible for reviewing those changes and giving other parties, namely ratepayer advocates and affected landowners, an opportunity to weigh in. Some commission staff sounded the alarm as the pile of revisions - and questions - grew. "I don't recall any other comparable cases in my experience with as many application material document revisions and ongoing design changes throughout the process," PSC Environmental Affairs Coordinator Adam Ingwell wrote in testimony filed last month. "The sheer volume of documents and revisions, without adequate explanation, likely makes it more challenging than typical for a member of the public to find specific information about the project." Those concerns reached Administrative Law Judge Michael Newmark, who criticized ATC for creating an "unreasonable burden" on commission staff and the public by scattering "a plethora of changes, modifications and updates" across six months of filings. ATC, on the other hand, cast the revisions as "routine." "Every application develops during review," the company's attorneys wrote on Wednesday. "Changes far larger and later than ATC's have never cast doubt" on whether an application should move forward, they added, citing a Barron County solar farm the PSC approved last March despite an "eleventh-hour" overhaul that included "relocating an entire substation." "There is simply no principled basis on which to treat ATC's lesser and earlier changes more harshly," the attorneys wrote. Ratepayer advocates weigh in. Ratepayer advocates generally avoid wading into fights over transmission line routes and substation siting, which Wisconsin Citizens Utility Board (CUB) Regulatory Affairs Director Corey Singletary described as a "zero-sum proposition" in which a victory for one group of landowners means shifting construction impacts onto another group of landowners. But CUB raised concerns that ATC's revisions make it difficult to forecast the project's cost. The route changes and new bypasses make the price tag "a moving target," said CUB Executive Director Tom Content, as does the possibility that ATC still attempts to complete the project by December 2027. "Would they be paying double overtime or triple overtime to build it that quickly?" The Wisconsin Utility Association itself weighed in on Wednesday to warn the PSC that any additional delays in the project will "lead to increased costs for customers." Transmission utilities generally pass along the costs of new infrastructure to ratepayers of all kinds via their electrical bills; Wimifm Energies, for instance, estimates that transmission-related costs account for about 10% of customers' bills. The PSC can't require ATC to assign project costs to the companies developing the Port Washington data center. Only FERC, the five-person federal regulator that oversees interstate transmission, could overhaul billing rules to fully shield other customers from the costs of new lines and substations needed to serve data centers. The commission offered an ad hoc solution this spring. The PSC's May order creating a new billing structure for Wimifm Energies' data center customers requires data center operators to pay a minimum transmission charge based on their projected electricity use. Wisconsin PSC Commissioner Kristi Nieto called the arrangement a "temporary stopgap measure" to protect other customers from the costs of overbuilt infrastructure if data centers use less electricity than anticipated. ATC and Wimifm Energies have since asked the PSC and FERC to approve a minimum transmission charge agreement with Microsoft, the operator of the vast new data center in Mount Pleasant. "This is a customer protection mechanism that follows the 'cost causer, cost payer' methodology," an ATC spokesperson wrote in an email to Wisconsin Watch. The utilities have not yet asked the commission to approve similar agreements with the companies developing the Port Washington facility: cloud computing giant Oracle, artificial intelligence firm OpenAI and data center developer Vantage. In testimony filed last month, Singletary urged the commission to enforce "cost containment" measures for ATC's project, including requiring the utility to cap its annual revenues from the new transmission lines. He also suggested that the commission push ATC to disclose any bids it receives for "work to be performed and equipment to be procured as part of this project," which he argued would help keep an eye on the company's efforts to rein in costs. 'Least-bad option' All three commissioners aired matching frustrations during a Thursday afternoon hearing on ATC's infrastructure plans before concurring on what Commissioner Marcus Hawkins called the "least-bad option" - requiring ATC to resubmit its application and restarting the case's 180-day clock. "There needs to be flexibility in the process," said Nieto, "but there also has to be some point at which the changes become significant enough that we need to evaluate whether we are still reviewing the same project that was originally proposed." "This PSC is not opposed or hostile to data centers, construction, generation, (or) transmission," Strand said, calling the decision "an unfortunate outcome." Nevertheless, she added, "this application represents a cautionary tale of when unrealistic and unreasonable speed-to-power expectations collide with a deliberative regulatory process." ATC has not indicated when it will resubmit its application as of Thursday afternoon, nor whether the December 2027 deadline is still within reach. "ATC is disappointed with today's Commission's decision and is considering its options," a company spokesperson wrote after the hearing. But the company's final filing before the hearing signaled the possibility of a legal fight. "To date, the Commission has processed the application consistent with the law," the company's attorneys wrote. "At this stage," restarting the process "would be the one action to depart from that."
A message from Village administrator-clerk schuh regarding ATC Utility Lines & Proposed Substation which will also be on the August 6, 2026, Board Agenda. A MESSAGE FROM ADMINISTRATOR CLERK KAREN SCHUH RE ATC UTILITY LINES AND PROPOSED SUBSTATION: All Village Board members received a letter dated July 14, 2026, on July 20, 2026. Rod Hise, ATC Local Relations Representative, retired on July 24, 2026, and its new contact is Zac Tretow. I have included some information in this board packet (8-6-26), but I would encourage the board and the public to go to https://www.atcllc.com/project/bluemound-elm-road-upgrade/ to view all the information regarding the proposed ATC project. Mr. Tretow stated ATC is in the process of negation with two property owners for the proposed substation. He stated the public is welcome to contact him with their concerns, and the Public Service Commission is the agency that will hold the public hearing for their request. Mr. Tretow stated elected official and the public can submit all their concerns they have with the project once the project becomes public. Mr. Tretow did state that he will send information to all property owners within the project area and all elected officials in the area. Please Note: The ATC Utility Lines and Proposed Substation is on the August 6, 2026, Village Board Agenda (4b)