U.S. clean-energy startup, Commonwealth Fusion Systems, raised an additional $84 million from major investors in Europe and Asia, underscoring that the appetite remains to back new technologies that could mitigate climate change. As the world looks to ramp up the use of intermittent renewable energy, it needs to add forms of flexible clean power that can be turned on whenever needed. That’s why investments in previously-fringe technologies like long-duration energy storage, hydrogen and nuclear fusion are taking off.

Singapore’s Temasek Holding Pte and Norway’s Equinor ASA were among equity investors in Commonwealth Fusion Systems’ latest round, according to Chief Executive Officer Bob Mumgaard, who said the cash will be used to build a headquarters and manufacturing facility. The company, called CFS, was founded by researchers at the Massachusetts Institute of Technology in 2018 and has now raised more than $200 million.

“We’re entering the next phase,” Mumgaard said. “It’s time to put down some roots, get us all under one roof, and build some hardware for the future fusion business line.”

Today’s nuclear power plants split atoms in a process that releases lots of energy, which can be turned into carbon-free electricity. But the current breed of fission reactors come with some important downsides, such as long-lasting radioactive waste and ballooning costs of construction, which have undermined public acceptance of the technology.

Fusion energy is the power that makes stars shine and is the opposite of fission. It unleashes energy by merging atoms together — usually hydrogen isotopes — in a process that generates temperatures exceeding 100 million degrees Celsius. If it can be made to work, the technology comes with the advantage of creating less waste and having a near-unlimited supply of fuel.

The difficulty is that no one has been able to build a reactor producing more energy than is consumed by controlling fusion reactions. It’s been the butt of scientific jokes for years among researchers who’ve jested that commercial fusion’s been only 30 years away since at least 1930.

But a new breed of startups would like to change that narrative. Scientific advances have resulted in important innovations, like stronger magnets, which help manage the sun-like temperatures fusion reactors reach. When combined with advanced computing power, Mumgaard believes nuclear fusion may be ready for prime time “faster than people thought.”

CFS aims to show that its high-temperature superconducting magnets work at scale next year, and then hopes to build a working prototype reactor by 2025 or sooner. If it succeeds to showcase that fusion reactions can be carried out with the help of these new types of magnets, then CFS will build a commercial reactor by the early 2030s, says Mumgaard.