Helion, a 12-year-old startup backed by Sam Altman, Peter Thiel and Reid Hoffman, has ingratiated itself amongst Silicon Valley heavyweights eager to unleash the commercial potential of nuclear fusion energy. Its ambitious promises have garnered the attention of deep-pocketed investors—and raised concerns amongst nuclear experts wary of the company’s aggressive timeline.
Fresh off a $425 million Series F funding round, Helion is now valued at $5.4 billion, the startup announced today (Jan. 28). The company’s co-founder and CEO David Kirtley said the massive capital is key to advancing its mission. “This accelerates the construction of the world’s first fusion power plant and then all our plants to come,” he said in a statement.
Nuclear fusion technology, which harnesses the energy produced when two atoms combine to form a larger one, has yet to be commercialized. Helion believes it can reach this milestone within the next three years, while other fusion companies have put forward decade-long timelines. Scientists are less optimistic. “I even think ten years is very ambitious,” Saskia Mordijck, a physics professor at The College of William & Mary, told Observer.
Helion has garnered considerable public attention largely because of Altman’s involvement. In 2021, the OpenAI CEO invested $375 million in the company, which is by far his largest ever personal investment. In a blog post at the time, Altman described Helion as “by far the most promising approach to fusion I’ve ever seen.”
Two years later, Helion unveiled a power purchase agreement with Microsoft (MSFT), OpenAI’s largest backer, aiming to begin delivering electricity to the Big Tech giant from a fusion plant by 2028.
Helion’s latest funding round saw participation from repeat investors like Altman himself and Facebook co-founder Dustin Muskovitz. New participants included Lightspeed Venture Partners and SoftBank (SFTBF)’s Vision 2 Fund. “I am very excited for what this funding will enable for us,” said Kirtley, adding that the capital infusion will help Helion build capacitors, magnets and semiconductors “much faster than we have been able to before.” Such devices are key to Helion’s Polaris reactor, the company’s seventh-generation prototype that lies at the heart of its fusion energy dreams.
How realistic are Helion’s promises?
Helion’s lofty promise has been met with skepticism from the science community. “They don’t share any information, they don’t publish, they don’t provide data, they don’t share scientific advances,” said Mordijck, adding that such secrecy “makes it really, really challenging for us to assess where they are in the development of their system.”
Excitement around nuclear fusion, however, has reached record highs—at least financially. Investors have flocked to nuclear fusion’s potential to one day provide vast amounts of clean energy, with total funding for nuclear fusion companies totaling $7.1 billion as of last summer, according to a report from Fusion Industry Association, $900 million of which was given in the past year .
Despite the optimism surrounding the field today, scientists warn there’s a thin line between stoking enthusiasm and managing expectations. “There should be a lot of responsibility when you give a date,” said Mordijck. “I do worry that—and it’s not just Helion—when all these companies promise specific dates and these dates are not being met, then the public will become skeptical because they will feel that they’re being lied to.”
