Down a long driveway, just off a rustic road in Stoughton, scientists are plugging away in a basement warehouse, trying to generate and confine plasma, the fourth state of matter.

They’re doing it in the WHAM: a cylinder connected through wires and cables with powerful magnets on both sides. The goal is to trap ionized particles long enough to generate plasma and keep the reaction going.

Plasma is what powers the stars, but creating it reliably on Earth is more difficult. Still, that’s what nuclear physicists are racing worldwide to do: scale this superheated soup of particles to produce a cleaner energy source amid a climate crisis.

“Energy is what underpins everything,” says Kieran Furlong, CEO and co-founder of Realta Fusion, a private nuclear fusion start-up formed in 2022. The start-up, with roughly 45 employees, has raised about $45 million. Furlong, a chemical engineer, has spent his career working on sustainability and energy. Sitting outside the WHAM on a picnic table, he says he sees nuclear fusion as the “future of energy for humanity.”

The fusion industry has been “at pains to educate people,” Furlong says, about the distinction between fusion and fission. He says it’s “a delicate balancing act, because the last thing I want to do is throw fission under the bus — but it has got inherent differences.” With fusion, there’s no risk of a runaway reaction, and there are no spent fuel rods. While fusion generates some radioactive waste, it’s similar to what’s generated by an X-ray lab in a hospital.

“The more I dig in, the more I realize we want all the wind and solar we can get. We need all the energy storage we can get, and it’s still not going to be enough. We need another massive source of energy,” he says, and he’s betting on fusion.

Scientists are racing to create nuclear fusion energy in two ways: through lasers or magnets. The WHAM uses magnets that can generate a magnetic field of 17 tesla, which is dramatically more powerful than a hospital MRI. WHAM is the reason Realta exists today. It was built with federal funding from the Department of Energy under a program meant to push research toward commercializing, and UW-Madison researchers work side-by-side with Realta on it.

Realta is now looking to build a R&D facility and are expecting to announce a location for “The Forge” in mid-July. The former Oscar Mayer building site in Madison, and an undisclosed location in New Jersey, are the finalists.

Furlong says a number of factors figure in their decision. One is finding an existing building and a power supplier (finding a site that hasn’t been “snapped up” by data centers already has been “challenging”). They also need a community that can attract talented physicists and engineers, and Madison has “so far proven to be quite successful at attracting people to move here.”

The company also needs to attract investment. Realta has raised two rounds of venture capital financing so far, but “fusion is a long road,” and Furlong says it would be helpful if investors could visit their research site without multiple flights. The cost of doing business and the carrot of financial incentives are also important. Here, state and local lawmakers have tried to sweeten the pot.

Nuclear energy, Gov. Tony Evers said in February, “could be a game-changer” for Wisconsin. On that he and most lawmakers seem to agree. In April, Evers signed into law a sales and use tax exemption for nuclear fusion that’ll last for 50 years. The bill received bipartisan support from the state Legislature; just nine of 131 legislators, all Democrats, voted no. (Realta lobbied for this bill, among others.)

Madison is following suit. In June, the city council unanimously approved $2.8 million in tax increment financing that specifically targets job creation. Under the agreement, Realta would need to clear staggered thresholds to get the benefits.

City staff recommended its approval. “This is an opportunity to grow a new industry sector that can provide employment and tax base,” city economic development director Matt Mikolajewski told the finance committee ahead of the resolution’s passage. He says this particular type of financing has been used to support other tech companies that promised jobs, including Extreme Engineering Solutions, Illumina and Exact Sciences.

In February, the 5 Lakes Institute received $778,000 in state economic development funding to launch the Wisconsin Fusion Energy Coalition to build an ecosystem around fusion energy. Executive director Kathleen Gallagher says it’s important to create a regional fusion ecosystem beyond Madison, even beyond Wisconsin.

“It’s not enough to just have the university,” she says. “You need the companies and all the related pieces that create an industry.”

Gallagher says if Wisconsin lost Realta or SHINE, another nuclear fusion start-up that spun off from UW-Madison, it would be a “disaster” for trying to build the ecosystem she’s championing.

Wisconsin lost a fusion company in 2024: Type One moved their headquarters to Tennessee, a state that’s established a $70 million incentive fund and last month announced a regulatory framework for fusion power plants. Type One is poised to develop a fusion power plant at the Tennessee Valley Authority.

“It’s really important not to lose another one,” Gallagher says.

As scientist Kai Shih takes Isthmus around the WHAM in late June, a purple blast of plasma flashes across a computer screen. A bell rings, and we take off our noise protection gear we’d put on for the test.

A scientist walks up to Furlong and tells him excitedly, “I got a video.” The Realta team appears genuinely excited, but they can’t yet tell me why. One thing is clear: After decades of research, nuclear fusion is now definitely a race.

When they installed the magnets on the WHAM, Realta and Commonwealth Fusion Systems, a Massachusetts-based supplier and fusion developer, set a world record for the system’s magnetic strength. Commonwealth has set another record: in April, they became the first fusion developer to request to connect to the electric grid.

Furlong says they are also looking to connect to the grid but, given the bureaucracy and engineering studies needed, it’s not necessarily their first priority. Realta could instead directly serve large customers, like data centers or petrochemical companies. He says they’ve been in conversations with hyperscale data centers, which he sees as “wind in the sails for any new energy technology,” adding that the demand for electricity, and energy autonomy, is also being driven by the electrification of vehicles and international affairs.

There’s a running joke in fusion circles that success is 20 years in the future, and always will be. But at this moment, Furlong thinks commercial applications are just around the corner: “Look, we’re doing a start-up. We’re a start-up in fusion, so that’s optimism squared. But if we’re not optimistic, what hope is there?”