Janesville residents write questions for city officials during a gathering about a proposed southside data center, held at the Woodman’s Sports & Convention Center, Tuesday, Nov. 4, 2025.
Janesville residents pack a meeting at the Woodman’s Sports & Convention Center, to hear about a proposed southside data center, Tuesday, Nov. 4, 2025.
Janesville city staff sort questions from attendees during a meeting about a proposed southside data center, held at the Woodman's Sports & Convention Center, Tuesday, Nov. 4, 2025.
JANESVILLE — A possible data center on the former GM/JATCO site on Janesville’s southside was the conversation of the day Tuesday at two separate gatherings, one hosted by the city of Janesville and another hosted by the citizens’ group SNOW.
Janesville residents write questions for city officials during a gathering about a proposed southside data center, held at the Woodman’s Sports & Convention Center, Tuesday, Nov. 4, 2025.
The meetings came as the city released a trove of information from a Colorado firm’s response to its August request for proposal, that sought firms interested in developing a data center on the 250-acre brownfield that once held the GM/JATCO operation.
SNOW, which stands for Southside Now, held the first of what it’s billing as informal “Coffee with a Council Member” sessions at Mocha Moment coffeeshop, 1121 Center Ave., on Tuesday afternoon.
The special guest Tuesday afternoon was Janesville City Council member Larry Squire, who told attendees the city is “committed to learning” about what putting a data center on the former GM/JATCO site on the southside would entail. Squire emphasized that no decisions have been made about whether to bring a data center to Janesville, and that the city remains in the very early stages of exploring the idea.
“We’re not saying ‘yes’ or ‘no,’” Squire said. “We are so far from that in my mind.”
The other meeting hosted by the city, and held Tuesday evening at the new Woodman’s Sports & Convention Center on Milton Avenue, drew about 300 people who came learn more about the potential data center project on the GM/JATCO site and to hear perspectives on it from city officials.
RFP response
The city shared at Tuesday’s meeting more information on a company that has shown an interest in such a development on the GM/JATCO site.
That follows several weeks of pushing by SNOW and others to release more information on who responded to a request for proposal issued by the city, regarding a data center on the GM/JATCO site.
In its response to the city’s RFP, Viridian Partners, of Greenwood Village, Colo., said it has successfully acquired, remediated and repositioned more than 1,200 acres of environmentally changed sites over its 22-year history.
Its proposed development plan would transform the brownfield former GM/JATCO site and a series of small adjacent properties, all of which the city has recently acquired through a condemnation process, into an envisioned state-of-the-art hyperscale data center campus with 8 to 11 buildings.
Viridian, in its response to the RFP, said it would commit to full site remediation, estimated at a cost of $30 million, and to making improvements to infrastructure on the site, at its own cost.
Viridian Partners estimated in its response that it would cost about $8 million to develop a data center on the former GM/JATCO site, with an ultimate valuation of about $2 billion.
It envisions hiring about 13,200 workers to construct the data center, generating $870 million in wages and benefits.
Janesville residents pack a meeting at the Woodman’s Sports & Convention Center, to hear about a proposed southside data center, Tuesday, Nov. 4, 2025.
Once fully operational, the data center could contribute $130 million annually to the local economy and provide 600 permanent jobs, the company said.
Lahner said Viridian Partners has expressed an openness to partnering with Blackhawk Technical College to create a workforce training program to support a local pipeline for permanent jobs at the data center. And he said the company has pledged to incorporate LEED-certified, energy-efficient building designs and use of renewable energy into the project.
Lahner said according to the company’s response to the RFP, an 11-building campus would use about 70,400 gallons of water per day, significantly less than GM at its peak. A developer’s agreement that would be adopted between the city and the firm would address things like noise and exterior lighting, he noted.
Lahner emphasized that the project is in its early stages of exploration, with a letter of intent being the next step. He said such a letter would allow either party to walk away without penalty while discussions continue, and said additional feasibility studies, environmental review and public hearings would occur before any final agreements were reached.
Environmental concerns
Addressing concerns that have swirled locally in recent months, Lahner said modern data centers have advanced cooling systems, limit noise and water usage, and tap into renewable energy sources to offset the environmental impact. He said power costs would not be passed onto local residents, and noted that the Public Service Commission of Wisconsin, not the city, regulates electricity rates.
New tax base
Laher further said the project could significantly increase the city’s tax base, generating new revenue for roads, public safety, and other services without raising property taxes. He noted that other cities that have gone forward with similar-sized data centers in Wisconsin and across the U.S. have seen local construction and trade jobs created and high-tech industry supply chains boosted.
He said that while researching the idea of a data center, he and other representatives of the city traveled to several data centers around Wisconsin and in other states, to see them first-hand and to assess their environmental and other impacts.
He noted that a development plan would be drafted with community oversight through an advisory committee and public meetings.
He said in other parts of the U.S., modern data centers have been successfully built in the middle of residential neighborhoods and across the street from multifamily units and said that surprised him. He also interviewed city leaders in Texas to help him understand the development process and related community outreach needs.
Janesville residents attend a meeting about a proposed southside data center, held at the Woodman’s Sports & Convention Center, Tuesday, Nov. 4, 2025.
Lahner acknowledged that some Janesville residents will remain opposed to the idea of a data center, and said their concerns are valid. However, he said the city is doing its due diligence so that the council has all the information it needs to ultimately make a good decision.
He said he’s encouraged by Viridian Partners’ response to the RFP, and that even if the data center were a short-term use on the site, and something else later replaced it, the city would get a fully remediated site and industrial buildings ready for other uses.
“If you believe that you’re against it… that is the end-all-be-all… no matter what I say or what I do is going to change your mind. That’s fine,” Lahner said. “I’m just sharing what my research and my information and data is, and what I’m using to make our recommendation.”
Letter of intent
The city council is expected to vote on approval of a letter of intent next Monday, Nov. 10. If approved, it would advance the project to allow for additional studies and planning.
The goal of that next phase would be to “figure out what are the real impacts of a potential data center here in Janesville, and to present a recommendation to the city council that’s as well informed as we possibly can be,” Lahner said.
‘Coffee With a Council Member’
At Tuesday afternoon’s session at Mocha Moment, Squire answered questions of attendees and said an aim was to leave people more comfortable with talking about a data center.
The small group who gathered at the coffeehouse voiced concerns about environmental impacts, particularly water and power use, noise and light pollution and neighborhood compatibility.
Squire said those questions are valid and part of what the city must study before moving forward.
“That’s going to take months to figure out,” he said, and will be part of a process in which “we’re looking at water, power, environmental, social and economic factors. Those are the five big ones.”
The group voiced concerns about the location, environmental safeguards and whether the city could walk away later in the process.
Squire said the city and council will retain the authority to walk away.
Janesville residents attend a meeting about a proposed southside data center, held at the Woodman’s Sports & Convention Center, Tuesday, Nov. 4, 2025.
“We can still say ‘no’ at any point along the way,” Squire said. “If something doesn’t make sense for Janesville, we stop.”
Several attendees urged Squire to make sure future city meetings are accessible and held across Janesville. He noted that city staff are aiming to schedule more sessions in neighborhoods and school buildings to keep residents informed.
Despite the concerns raised Tuesday, Squire said he believes the conversations are positive a step.
Janesville city staff sort questions from attendees during a meeting about a proposed southside data center, held at the Woodman's Sports & Convention Center, Tuesday, Nov. 4, 2025.
“You build trust one conversation at a time,” he said. “Trust is the biggest issue right now, but that’s how we fix it — by showing up and talking about it.”
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