Who Will Build Wisconsin’s Grid for New Data Centers?

The Midwest's data center boom is driving a massive electrical transmission buildout, leading to a contention over which developers will construct the necessary infrastructure in Wisconsin. Last week, the Midcontinent Independent System Operator (MISO), the regional grid operator, reversed an earlier decision, reassigning a series of substations in eastern Wisconsin from Viridon, a developer backed by the investment firm Blackstone, to the American Transmission Company (ATC). MISO's decision was influenced by the urgent timeline of a new $15 billion Vantage Data Centers campus in Port Washington, which requires connection to the grid by early 2028. ATC, which owns most transmission lines in eastern and central Wisconsin, argued it was better positioned to complete the project on schedule, with the reassigned substations now integrated into a larger $1.3 billion buildout to serve the Port Washington campus. This move marks a win for ATC after legislative setbacks in the Wisconsin Assembly where proposals to grant local developers a monopoly on multistate transmission projects have been rejected. The reassignment fuels an ongoing debate about competitive bidding versus right-of-first-refusal (ROFR) laws. Ratepayer advocacy groups, including Wisconsin’s Citizens Utility Board, contend that competitive bidding lowers consumer costs by preventing monopolies. However, ATC and established utilities argue that local experience ensures timely and efficient project completion, avoiding delays newcomers might face. Viridon's attorneys have raised concerns with the Wisconsin Public Service Commission (PSC) that allowing ATC to build the substations circumvents MISO's planning processes and could lead to higher costs for Wisconsin customers. While the Port Washington city council has approved the data center project, the final outcome for the transmission buildout, including where infrastructure will be built and who bears the ultimate cost, remains pending with the Wisconsin PSC. The commission is currently reviewing ATC's application as construction crews race to bring the Port Washington data center online by the end of next year, highlighting the urgency of securing the necessary power supply.