For students walking into the new Sonnentag Center near the University of Wisconsin-Eau Claire campus, the first thing they notice isn’t the long list of sustainable features that make this a LEED Gold certified building. They notice how bright and airy it is.

"When students enter this building, the thought in their minds isn't like, ‘Oh, I can tell this is a sustainable building’,” said Kristen O’Brien, student director, Student Office of Sustainability, UWEC. “Just ‘This is a beautiful building.’ Opting for sustainable construction practices doesn't mean you have to compromise on quality."

As the largest indoor event venue in northwestern Wisconsin, the Sonnentag Center is poised to be a critical community hub for generations to come. From the state-of-the-art fieldhouse to the Mayo Clinic sports medicine center to the large indoor arena, the Sonnentag is not making any compromises on amenities for the students and residents of the Chippewa Valley. 

Nor are they compromising on sustainable design. An interactive touchscreen in the lobby of the building maps out all the best-in-class features: a geothermal heat pump for heating and cooling, LED lighting throughout, automated lighting systems, high-efficiency water fixtures, non-irrigated landscaping, EV charging stations and more.

And quietly powering the whole operation is an Xcel Energy solar array 13 miles away.

Chippewa Sun solar array

The Chippewa Sun solar array is a five-megawatt solar photovoltaic system located in the Town of Hallie, Wisconsin. This community solar project generates approximately 10 million kilowatt-hours of clean electricity annually.

Opened in March 2025, the solar array connects local businesses and organizations to renewable energy through a subscription model. The Sonnentag Center is the largest subscriber, using solar energy to offset 100% of electricity consumption. Other subscribing partners include the Pablo Group and the City of Eau Claire. 

The system works by having Xcel Energy purchase the electricity from the solar array and distribute it through their grid system to support these subscribing partners. This arrangement allows the organizations to access clean, reliable solar energy while supporting their individual sustainability goals and the broader transition to carbon-free electricity, all without having to build, own or maintain their own solar installations.

Though the designers of the Sonnentag Center initially considered building and operating their own solar array, they quickly realized their clean energy goals were easier to reach in collaboration with Xcel Energy.

“We knew because of the relationship with Xcel Energy, ‘Hey, here's somebody who knows how to do this stuff,’” said Disa Wahlstrand, VP of Engineering Services at Ayres Associates. “The scale of power we want for the facility, turning to Xcel Energy gave us great confidence in it being done and being done right.”

A collaboration forged in community

Xcel Energy's Wisconsin operations are rooted in clean renewable energy generation. Beginning over a century ago with hydroelectric power, that early commitment to sustainable electricity production has remained central to operations in the state.

Today, Xcel Energy operates an extensive hydroelectric infrastructure in Wisconsin, including 19 projects across eight rivers that collectively generate around 270 megawatts of carbon-free electricity. The company has expanded its renewable energy portfolio in Wisconsin to include solar power, as well as two biomass facilities located in Ashland and La Crosse.

It's Xcel Energy’s long legacy of advancing clean energy solutions in the state that led UWEC to reach out when the time came to build the Sonnentag Center.

“We think if you invite everyone to the table, you get a far better outcome,” said James Schmidt, Chancellor of UWEC. “Change happens at the speed of trust. We have found Xcel Energy to pull up a chair at the table and say, ‘what are you trying to accomplish? We'll bring our expertise to the table to help make sure you can accomplish your goals.’”

That spirit of collaboration was present in every step of the Sonnentag process — from involving the students and the Student Office of Sustainability in the planning and funding to hiring the engineers at Ayres Associates to guide the sustainable construction practices, to consulting the energy experts at Xcel Energy, who made sure the whole thing was powered with 100% clean, renewable solar energy.

“Xcel Energy wants to work with you,” said Schmidt. “They want to sit down with you. They're going to help you design the best facility possible because it's good for everybody. It's good for their customers, and it's good for the utility to have more planned energy usage. And that's where they bring their expertise. And frankly, we wouldn't have been able to figure out many of the grants they were able to get to help offset the costs of some of these energy efficient models without Xcel Energy's expertise.”

The Sonnentag Center is a story of sustainability and, ultimately, teamwork, said Wahlstrand.

"To have those longstanding relationships when you're going to go after a big goal, like zero net energy, to have trust in a partner like Xcel Energy — it makes that much more feasible.”

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Xcel Energy

Local office: 1414 W. Hamilton Ave., Eau Claire

Phone number: (800) 895-4999

Website: wi.my.xcelenergy.com

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