13 Best Fusion Power Startups to Watch in 2025

The Definitive Seedtable Ranking of Fusion Power Startups

We track 71,000+ companies and rank them dynamically using our Seedtable Score – a score that uses quantitative and qualitative data points to signal the momentum behind a company. We then monitor the list manually leveraging our expertise as founders and investors.

There are 13 start-ups with an aggregate funding of $5.5b. The average funding per company in this subset is $423.0m.

Last update to the database: Sep 2, 2025. See changelog.

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6

Funding Rounds

$577.8m

Money raised

Helion Energy is a fusion power company aiming to build the world's first fusion power plant.

Key people:

6

Funding Rounds

$3.0b

Money raised

Commonwealth Fusion Systems is a Cambridge, Massachusetts-based research and development company developing fusion power systems based on ARC tokamak reactors.

2

Funding Rounds

$5.0m

Money raised

Avalanche Energy Designs is an American start-up company designing, testing, and building micro-fusion reactors.

Location:

Key people:

2

Funding Rounds

$49.2m

Money raised

Renaissance Fusion is a nuclear fusion reactor manufacturer founded in 2020 by Francesco A Volpe.

Location:

Key people:

7

Funding Rounds

$172.1m

Money raised

Tokamak Energy is a fusion energy producer founded in 2009 by Alan Sykes, David Kingham and Mikhail Gryaznevich.

Key people:

7

Funding Rounds

$332.8m

Money raised

Zap Energy is developing compact fusion power that doesn't require magnets or lasers.

1

Funding Rounds

$150.0k

Money raised

HelicitySpace is a fusion propulsion and power company, developing technology for spacecraft.

Key people:

3

Funding Rounds

$93.0m

Money raised

Marvel Fusion is a laser-powered fusion energy technology developer founded in 2019 by Moritz von der Linden.

Location:

Key people:

1

Funding Rounds

$3.1m

Money raised

Company that has developed and operates the world's first continuous-operation enabled, superconducting, high-beta style fusion research device.

1

Funding Rounds

$3.0m

Money raised

A nuclear fusion research company based in Tempe, Arizona.

11

Funding Rounds

$1.2b

Money raised

TAE Technologies, Inc., formerly known as Tri Alpha Energy, is a California-based renewable energy company focused on developing commercial fusion energy.

1

Funding Rounds

$15.0m

Money raised

Industries:

1

Funding Rounds

$15.0m

Money raised

Helical Fusion is a Tokyo-based deep-tech company developing advanced nuclear fusion reactors using helical coil technology. Spun out from Japan’s National Institute for Fusion Science, it focuses on delivering safe, sustainable, and scalable clean energy solutions for global climate and energy challenges.

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