Nuclear fusion is on the upswing, as more companies pile into the space to achieve what’s often described as the Holy Grail of clean energy, according to an updated map from the Clean Air Task Force (CATF).

Nuclear fusion aims to replicate the way the Sun produces light and heat, generating a tremendous amount of energy when atomic nuclei fuse together. Figuring out how to do that in a controlled way on Earth would unlock an energy source that avoids the greenhouse gas pollution from fossil fuels and radioactive waste from existing nuclear fission reactors that split atoms apart.

That’s all easier said than done, of course. Researchers have been chasing the dream for nearly a century. The biggest breakthrough yet took place in 2022, when researchers were able to reach a net energy gain from a fusion reaction for the very first time. That took place at the Lawrence Livermore National Laboratory in California, and other initiatives are still trying to replicate that success with the goal of one day being able to generate electricity from a fusion power plant.

Those efforts are ramping up, according to CATF citing publicly available resources and its own discussions with individual companies and investors. The number of companies developing fusion technologies has grown, particularly in North America and Europe. You can take a look at CATF’s fusion map to see where this is all happening, including government-supported programs.

Other experts The Verge has spoken to over the years say it could take decades longer before fusion energy becomes commercially viable, assuming developers ever overcome the engineering challenges.

“There is still a lot of scientific and engineering work that these companies need to complete before they produce net energy, but these companies have created a clear roadmap to commercialization for investors and the market is responding,” says Patrick White, group lead for fusion energy and safety regulation, in an email to The Verge.

Fifty-three fusion companies have received a total of $8.9 billion in private funding and $795 million in public funding, according to a 2025 survey by the Fusion Industry Association. That’s compared to just 23 respondents who reported a combined total $1.9 billion in private and public funding in 2021.