Nine utility-scale solar arrays, featuring more than 1.6 million photovoltaic modules, are bringing net-zero electricity to residents across Wisconsin following the completion of Alliant Energy’s solar program in December 2023.

Scope of work covered nine project sites with the installation of more than 1.6 million solar modules combined. Many of these panels are bifacial and collect energy from both sides. This increases site efficiency and helps maximize energy generation in winter when snow on the ground reflects light.

Work also included installation of more than 1,855 miles of power cables, 6.6 million linear ft of AC/DC cables and 13.6 million linear ft of string cables. The program has added 664 MW of solar generation to the grid, which is enough to power approximately 174,000 homes annually.

Photo courtesy of Burns & McDonnell

Crews completed more than 1 million direct craft hours in less than two years to deliver all nine projects on time and within budget. In addition to power, these facilities offer long-term economic and financial benefits to the local communities.

Just-in-time grading analysis helped ensure steel pile installation proceeded in the correct locations and heights in one take. To install more than 300,000 steel piles across all the sites—which included one of the largest purchase orders in Burns & McDonnell’s history—crews used PD-10 and Hercules pile drivers, each fitted with GPS monitors to ensure precise installation. The project team also coordinated with the Operating Engineers Local 139 to help develop a training program to utilize the PD-10 and GPS equipment, helping prepare its membership for a coinciding boom in solar work across the state. Project leadership also teamed with the North Central States Regional Council of Carpenters (NCSRCC) to establish tracker and module installation training before crews mobilized.

Photo courtesy of Burns & McDonnell

With construction progressing in the middle of supply chain constraints, the team ran into delays on permanent circuit breakers. To maintain the schedule until they could be delivered, temporary high-voltage gas circuit breakers were decommissioned and transferred from an Alliant Energy coal plant.

Ensuring each site was built in a way that would benefit the environment, the project team followed the Envision Sustainability Framework across all nine projects. Six have been awarded Platinum Envision ISI certification, while the other three sites are expecting to receive the same upon their verification.

Photo courtesy of Burns & McDonnell

Crews planted site-specific native grass and seed mixes approved by the Wisconsin Dept. of Natural Resources at each site as well, with the mix tailored to the site’s conditions to help build soil nutrients and attract pollinators and other beneficial wildlife populations. This pollinator-friendly vegetation is a proven method of preventing soil erosion, improving water quality and decreasing sitewide operation and maintenance costs.