Thea Energy lands $20M federal grant to build its magnets for fusion reactors

For hard-tech startups, manufacturing is a pricey endeavor. Now, Thea Energy has a leg up courtesy of a Department of Energy grant.

The fusion power startup told TechCrunch Monday that it has received a $20 million award from ARPA-E to help manufacture its modular high-temperature superconducting (HTS) magnets.

HTS magnets are costly but important components in any magnetic confinement reactor, one of the two main ways startups are attempting to harness fusion power for commercial purposes. In magnetic confinement reactors, powerful magnetic fields contain and compress plasma, helping to heat the particles until the fuel can fuse and release large amounts of energy.

Thea’s reactor is based on a design known as a stellarator. Stellarators look like inner tubes that have been twisted and squeezed in ways that help it confine the plasma more effectively. Most stellarators use magnets that are built to mimic those twists and turns, which makes them expensive to manufacture. 

To minimize manufacturing costs, Thea uses fewer variants. The 12 large magnets that do the heavy lifting are made from four different templates, and the more than 300 smaller magnets used to fine tune the plasma are all identical. They’re arrayed around the periphery of the reactor, similar to how pixels are distributed across a computer display. 

The small magnets are controlled by software, an arrangement should allow for more forgiving construction tolerances, which could lower costs, Thea says.

Thea is among the top funded fusion power startups, having raised $100 million in May on top of a $20 million Series A it raised in 2024. Like many of its peers, Thea has plans to build a commercial scale fusion power plant in the mid-2040s.