Thea Energy, a US fusion power startup, has been awarded a $20 million grant from the Department of Energy's ARPA-E programme to help manufacture its modular high-temperature superconducting (HTS) magnets. HTS magnets are a costly but essential component of magnetic confinement fusion reactors, which use powerful magnetic fields to contain and heat plasma until nuclear fusion occurs, and the funding underlines growing government backing for private fusion ventures as they push towards commercial viability.

Thea's reactor uses a stellarator design, whose twisted shape usually requires expensive, bespoke magnets. Thea reduces costs by building its 12 large magnets from just four templates and using over 300 identical, software-controlled smaller magnets arranged around the reactor's edge to fine-tune the plasma, an approach the company says allows for more forgiving manufacturing tolerances. The grant adds to Thea's substantial private backing, including a $100 million raise in May 2026 and a $20 million Series A in 2024, as it works towards a commercial-scale fusion power plant it aims to build by the mid-2040s.