Thea Energy, one of the newer entrants into the red-hot fusion energy space, raised $20 million last year as investors took a bet on the physics behind the company’s novel approach to creating magnetic fields. Today, in a paper being submitted for peer review, Thea announced that its theoretical science actually works in the real world. The company’s CEO, Brian Berzin, told me that Thea achieved this milestone “quicker and for less capital than we thought,” something that’s rare in an industry long-mocked for perpetually being 30 years away.
Thea is building a stellarator fusion reactor, which typically looks like a twisted version of the more common donut-shaped tokamak. But as Berzin explained to me, Thea’s stellarator is designed to be simpler to manufacture than the industry standard. “We don’t like high tech stuff,” Berzin told me — a statement that sounds equally anathema to industry norms as the idea of a fusion project running ahead of schedule. “We like stuff that can be stamped and forged and have simple manufacturing processes.”
The company thinks it can achieve simplicity via its artificial intelligence software, which controls the reactor’s magnetic field keeping the unruly plasma at the heart of the fusion reaction confined and stabilized. Unlike typical stellarators, which rely on the ultra-precise manufacturing and installment of dozens of huge, twisted magnets, Thea’s design uses exactly 450 smaller, simpler planar magnets, arranged in the more familiar donut-shaped configuration. These magnets are still able to generate a helical magnetic field — thought to keep the plasma better stabilized than a tokamak — because each magnet is individually controlled via the company’s software, just like “the array of pixels in your computer screen,” Berzin told me.
“We’re able to utilize the control system that we built and very specifically modulate and control each magnet slightly differently,” Berzin explained, allowing Thea to “make those really complicated, really precise magnetic fields that you need for a stellarator, but with simple hardware.”
This should make manufacturing a whole lot easier and cheaper, Berzin told me. If one of Thea’s magnets is mounted somewhat imperfectly, or wear and tear of the power plant slightly shifts its location or degrades its performance over time, Thea’s AI system can automatically compensate. “It then can just tune that magnet slightly differently — it turns that magnet down, it turns the one next to it up, and the magnetic field stays perfect,” Berzin explained. As he told me, a system that relies on hardware precision is generally much more expensive than a system that depends on well-designed software. The idea is that Thea’s magnets can thus be mass manufactured in a way that’s conducive to “a business versus a science project.”
In 2023, Thea published a technical report proving out the physics behind its so-called “planar coil stellarator,” which allowed the company to raise its $20 million Series A last year, led by the climate tech firm Prelude Ventures. To validate the hardware behind its initial concept, Thea built a 3x3 array of magnets, representative of one section of its overall “donut” shaped reactor. This array was then integrated with Thea’s software and brought online towards the end of last year.
The results that Thea announced today were obtained during testing last month, and prove that the company can create and precisely control the complex magnetic field shapes necessary for fusion power. These results will allow the company to raise a Series B in the “next couple of years,” Berzin said. During this time, Thea will be working to scale up manufacturing such that it can progress from making one or two magnets per week to making multiple per day at its New Jersey-based facility.
The company’s engineers are also planning to stress test their AI software, such that it can adapt to a range of issues that could arise after decades of fusion power plant operation. “So we’re going to start breaking hardware in this device over the next month or two,” Berzin told me. “We’re purposely going to mismount a magnet by a centimeter, put it back in and not tell the control system what we did. And then we’re going to purposely short out some of the magnetic coils.” If the system can create a strong, stable magnetic field anyway, this will serve as further proof of concept for Thea’s software-oriented approach to a simplified reactor design.
The company is still years away from producing actual fusion power though. Like many others in the space, Thea hopes to bring fusion electrons to the grid sometime in the 2030s. Maybe this simple hardware, advanced software approach is what will finally do the trick.
A transformer factory in Jiangsu Province, China. Costfoto/NurPhoto via Getty Images
