ATC's Central Wisconsin 345-kV Rebuild Enters Active Construction
American Transmission Co. has moved its Grid Forward Central Wisconsin Project into active construction, installing the first transmission structure on a 345-kV rebuild that is now about 5% complete, T&D World reports.
Market Impact
The project, approved through MISO’s Long Range Transmission Planning Tranche 1 portfolio, involves rebuilding and expanding existing 345-kV transmission infrastructure across central Wisconsin. ATC began line construction in the second quarter of 2026 and says the work remains on schedule for a December 2030 in-service date. Engineering, permitting, and material procurement are continuing across multiple line segments and substations.
“Grid Forward is an important investment in the region’s electric infrastructure and future reliability,” said Eric Lundberg, ATC’s senior vice president of Asset Delivery. “Construction is underway, major milestones are being achieved and the project remains on track.”
ATC says the project is forecast to stay within the cost range approved by the Public Service Commission of Wisconsin, and within about 2.5% of MISO’s original 2022 cost estimate when adjusted for time value of money. A revenue requirement analysis prepared in support of the project estimates roughly $1.75 billion in net savings for Wisconsin customers over its lifetime, or about $142 million on a discounted basis.
What It Means for Subcontractors
- Transmission line crews, structure erection contractors, and civil/foundation subcontractors should expect a multi-year build window through December 2030, with work now shifting from engineering to physical construction on line segments and substations.
- ATC is still in permitting and material procurement phases for later construction packages, meaning subcontract opportunities tied to substation work and additional line segments are likely still being released rather than fully awarded.
- Firms with 345-kV rebuild experience, including structure installation and rebuild-in-place work on existing corridors, have a live reference project to point to when bidding similar MISO Tranche 1 work elsewhere in the Midwest.
- Cost discipline is a stated priority for ATC, with the utility publicly tracking spend against both the Wisconsin PSC-approved range and MISO’s original estimate. Subcontractors bidding packages should expect scrutiny on change orders and cost variance reporting given this public cost-tracking posture.
- Companies working the broader MISO footprint should monitor ATC’s Grid Forward project updates for the release of substation-specific scopes, since engineering on those facilities is still described as “advancing” rather than complete.
