With a new $100M raise, Princeton’s Thea Energy is now a top-funded fusion startup

Source: TechCrunch

Thea Energy has raised an oversubscribed $100 million Series B led by the U.S. Innovative Technology Fund, the fusion startup told TechCrunch. The sum places the company among the better‑funded fusion startups, improving its chances of delivering a commercial reactor.

Funding round

• The new round brings total private investment to $130 million (including a $20 million Series A closed earlier in 2024).
• Other investors participating in the round include General Innovation Capital Partners, Linse Capital, Calm Ventures, Climate Capital, Divergent Capital, Emerald Technology Ventures, Gaingels, Idemitsu Kosan, Overlay Capital, Timescale Ventures, and Whatif Ventures.

The funding will help Thea expand manufacturing for its uniquely designed smaller magnets and begin construction of Eos, its “power‑plant‑relevant” demonstration device, starting next year.

Technology overview

Magnets are at the core of most fusion power‑plant designs—they keep the super‑heated plasma compressed and hot enough for fusion. Thea’s approach differs:

• Pixel‑inspired rectangular magnets – each magnet can be individually tuned to shape the overall magnetic field, similar to pixels on a computer monitor that follow software instructions.
• The design targets a stellarator configuration, which offers very stable plasma confinement but traditionally requires complex, twisted magnet structures.
• By surrounding the reactor core with dozens of regular, turnable magnets, Thea uses software to create a stellarator‑shaped field inside a simpler physical structure.

The software also aids assembly. Thea purposefully installed test magnets out of alignment, and the control system compensated for the mis‑placement.

Demonstration reactor and timeline

• Eos – a “power‑plant‑relevant” demonstration device slated for completion in 2030.
• Helios – the commercial version planned for 2034, aligning with competitors such as Commonwealth Fusion Systems, which targets an early‑2030s debut for its Arc reactor in Virginia.

Update: Thea’s early designs called for the use of 12 encircling magnets. They were not added to later versions.

Manufacturing advantage

• Dozens of full‑scale magnet iterations have been built in Thea’s Jersey City lab, avoiding the massive assembly halls required by other magnetic‑confinement startups.
• The reactor relies on 12 larger magnets (four shapes) for primary plasma confinement, while 300+ smaller magnets fine‑tune the plasma. This hybrid approach preserves some manufacturing simplicity while still needing the larger magnets.

Visual illustration

Image credit: Thea Energy