Thea Energy unveils Helios, a fusion power facility modeled after pixel technology

Reimagining Fusion Power: Thea Energy’s Innovative Approach

Fusion energy could dramatically transform the global energy landscape, but before that can happen, startups must demonstrate that their reactors are both effective and affordable. Achieving this is no small feat, especially since many fusion designs rely on enormous magnets and lasers that require installation with extreme precision.

Thea Energy, a fusion startup, believes its reactor—drawing inspiration from pixel technology and powered by advanced control software—can generate electricity without demanding such exacting standards.

“Our system doesn’t need to be perfect from the outset,” explained Brian Berzin, Thea Energy’s co-founder and CEO, in an interview with TechCrunch. “We’ve developed a method to compensate for imperfections after the fact.” This flexibility could give Thea a significant advantage over its competitors.

While fusion plants have the potential to supply vast amounts of clean energy, the high costs of materials and construction threaten their competitiveness against inexpensive solar and wind options. Thea’s strategy is to construct a plant first and refine its performance through software, potentially slashing the cost of fusion power.

Animation: Helios reactor can be taken apart for maintenance.
Image Credits: Thea Energy

However, the company’s immediate challenge is to build a functional prototype. Today, Thea is unveiling the specifics of its reactor design and the underlying physics, sharing its research exclusively with TechCrunch.

A New Take on the Stellarator

Thea is developing a novel version of the stellarator—a type of fusion reactor that uses magnetic fields to control plasma. In fusion science, magnets are one of the primary tools for containing the superheated plasma necessary for fusion reactions. The alternative method, called inertial confinement, uses lasers or other forces to compress small pellets of fuel.

Traditional stellarators often feature magnets with complex, twisted shapes reminiscent of surrealist art. In contrast, Thea’s design employs twelve large magnets alongside hundreds of smaller ones to create what could be described as a “virtual” stellarator.

Conventional stellarators use magnets shaped to match the plasma’s contours, allowing for longer confinement with less energy compared to tokamaks, which use identical magnets. The downside is that these irregular magnets are difficult to mass-produce.

Thea’s solution is to use small, uniform superconducting magnets arranged in precise arrays. Each magnet is individually controlled by software, generating magnetic fields that mimic the intricate shapes required for plasma confinement.

Cutaway illustration: Plasma moving through the core of the Helios reactor.
Image Credits: Thea Energy

Advantages of Modular Magnet Design

This modular approach offers several benefits. For one, it has enabled Thea to rapidly iterate on its magnet designs—over the past two years, the company has made more than 60 design changes, according to Berzin. “Most fusion companies are working with magnets or lasers the size of a car, each costing millions and taking years to produce,” he noted.

Additionally, the use of software controls allows Thea to compensate for any inconsistencies in magnet manufacturing or installation. To validate its control system, Thea constructed a 3x3 magnet array equipped with sensors. The system, based on electromagnetic physics, performed well. The company also experimented with artificial intelligence, training a new control system using reinforcement learning techniques.

The results exceeded expectations.

“We intentionally introduced errors into the array,” Berzin shared. “We even misaligned a magnet by over a centimeter—it was visibly out of place. We also tested superconducting materials from five different suppliers, including some with known defects. Each time, the control system automatically corrected for these issues without manual intervention.”

The Helios Reactor: Design and Ambitions

Thea’s Helios reactor will utilize two types of magnets. On the exterior, twelve large magnets of four distinct shapes will maintain plasma confinement, similar to those used in tokamak reactors like those being developed by Commonwealth Fusion Systems. Inside, 324 smaller circular magnets will fine-tune the plasma’s configuration.

The company estimates that Helios will produce 1.1 gigawatts of thermal energy, which will be converted by a steam turbine into 390 megawatts of electricity at a cost below $150 per megawatt-hour. The reactor is designed to undergo an 84-day maintenance shutdown every two years, resulting in a projected capacity factor of 88%—higher than most gas-fired plants and nearly matching today’s nuclear facilities.

Currently, Helios remains a concept. Thea’s first step is to build Eos, a prototype intended to validate the scientific principles behind the design. Berzin anticipates announcing the Eos site in 2026, with plans to begin operations around 2030.

While developing Eos, Thea will also start work on Helios, mirroring the approach of Commonwealth Fusion Systems, which is simultaneously advancing its commercial Arc plant and demonstration Sparc facility.

Looking Ahead

For now, Berzin is eager to receive feedback from the fusion research community. “This is the release of our overview paper, and it will be followed by extensive peer-reviewed publications,” he said. “Now is the time to establish partnerships, foster collaborations, and engage future users to help build the first reactor.”