Over the last few years, fusion power has gone from the butt of jokes — always a decade away! — to an increasingly tangible technology that has drawn investors off the sidelines. The promise is clear: harnessing the nuclear reaction that powers the sun to generate nearly limitless energy here on Earth.

The bullish wave buoyed by three advances—more powerful computer chips, sophisticated AI, and high-temperature superconducting magnets—has delivered more sophisticated reactor designs, better simulations, and complex control schemes. In 2022, a U.S. Department of Energy lab announced that it had produced a controlled fusion reaction, crossing the scientific breakeven point.

Founders are building on this momentum with rapid progress. Commonwealth Fusion Systems (CFS) leads the pack with $3.94 billion in funding and is set to build its first-of-a-kind power plant (Sparc), aiming for commercial relevance by 2027. Helion, based in Washington, has a more aggressive timeline, planning on producing electricity from its reactor in 2028 as its first customer.

TAE Technologies, founded in 1998, uses field-reversed configurations and particle beams to improve plasma stability, aiming for a $6 billion valuation through a merger with Trump Media & Technology Group. Pacific Fusion has started with an impressive Series A topping $1 billion.