Fusion power has the potential to rewrite the trillion-dollar energy market, but first, startups must prove that their designs will work and not be too expensive. Neither is easy, especially when the huge magnets and lasers used in many designs must be installed with millimeter precision or better.
fusion startup Theia Energy says its pixel-inspired reactor and specialized control software should be able to generate power without requiring the same level of perfection.
“It may not be that great in the beginning,” Brian Berzin, co-founder and CEO of Theia Energy, told TechCrunch. “We have a way to address last mile vulnerabilities.” That margin of error could give Thea an edge over the competition.
Fusion power plants promise to deliver gigawatts of clean electricity to the grid, but materials and construction costs threaten to make them uncompetitive with cheap solar and wind. By building a power plant first and plugging holes in the software, Theia could help dramatically reduce the cost of fusion power.
But first the company will have to create a working prototype. Today, Theia is publishing details of its design, including details of the physics that underpin it. The startup shared the paper exclusively with TechCrunch.
Theia is building a unique take on the stellarator, a specific type of reactor that uses magnets to shape plasma fuel. Magnets are one of the two main ways fusion scientists keep plasma hot and confine the plasma long enough for the fusion reaction to occur. The second, known as inertial confinement, uses a laser or some other force to squeeze smaller fuel pellets.
Most stellarators are made from magnets that look like a house in a Salvador Dali painting. But Theia’s design uses a dozen large magnets and hundreds of smaller magnets to create what you might call a “virtual” stellarator.
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In a typical stellarator, the magnets are made to follow the contours of a shape intended to work with the quirks of the plasma, helping to keep it confined for longer periods of time using less power than tokamaks, which use an array of magnets of similar size and shape. Yet stellarators have a major disadvantage: the irregular shape makes manufacturing magnets on a large scale challenging.
So instead, Theia designed its reactor around small, identical superconducting magnets arranged in arrays. The startup will use software to individually control each magnet to generate a magnetic field that can replicate the stellarator’s wobbly shape.
There are several advantages to this approach. For one, it has allowed Theia to iterate faster on its magnet designs. The company has changed the design more than 60 times over the past two years, Berzin said. “Most fusion companies, you’re dealing with car-sized magnets or car-sized lasers or car-sized widgets. Unfortunately that means one costs $20 million and takes two years (to build),” he said.
It also means the company can use software controls to smooth out any irregularities in the way the magnets are made or installed. To test its original control system, Theia built a three-by-three array of its magnets containing sensors. The controls, which were derived from the physics of electromagnetism, worked well. But the company also wanted to see how AI could handle this task, so it also created a new training model using reinforced learning.
The team was amazed at how well it all worked.
“We intentionally threw curveballs at the array,” Berzin said. “We deliberately made one of the magnets too big by about a centimeter. You could see it was completely out of line. It was really hard for us to actually produce it that poorly.” The team also tested superconducting materials from five different manufacturers with intentionally defective materials. “Every time we did that, the control system was able to fix those faults without us turning knobs and intervening,” he said.
Theia’s reactor design, Helios, will use two types of magnets. Outside one, 12 large magnets of four different sizes will do the heavy lifting to keep the plasma confined. They are similar to those found on the tokamak, the donut-shaped reactor that competing Commonwealth fusion systems are building. Inside the large coil, 324 tiny circular magnets will fix the shape of the plasma.
The startup estimates that Helios will generate 1.1 gigawatts of heat, which a steam turbine will convert into 390 megawatts of electricity at a cost of less than $150 per megawatt-hour. The reactor must be shut down for an 84-day maintenance period once every two years. If all goes well, that means its capacity factor – how much electricity it produces in a given period of time – will be 88%. he is very good Compared to today’s gas-fired power plants and almost as good as today’s nuclear power plants.
Helios is still in the conceptual stage. Theia is to first build EOS, its initial fusion device intended to prove the science behind the concept. Berzin said the company will announce a site for EOS in 2026 and plans to have it operational “around 2030.”
As it builds Eos, Theia plans to begin work on Helios in parallel. It’s a similar approach to how Commonwealth Fusion Systems is moving forward with work on its first commercial power plant, Arc, while Spark is building its demonstration plant.
For now, Berzin is eager to hear what the Fusion community thinks. “This is the release of the overview paper. This will be followed by a considerable amount of work which will come through peer review and publication,” he said. “Now is the time to move forward and establish partnerships, collaborations, involve end users to build the first.”
