Fusion Startup Helion Powers Up With $425M Series F

Chris Metinko

Fusion startup Helion Energy locked up a $425 million Series F — valuing the company at $5.4 billion — as the company looks to commercialize its fusion technology.

The round included participation from new investors Lightspeed Venture Partners, SoftBank Vision Fund 2 and a university endowment, as well as existing investors including Sam Altman, Mithril Capital Management, Capricorn Investment Group, Good Ventures and Nucor Corp.

The Everett, Washington-based startup has now raised more than $1 billion. In November 2021, Helion closed a $500 million Series E.

The new round further illustrates investors’ appetite for new energy sources as power needs increase due to AI and other advances. In 2023, Helion announced a power purchase agreement with Microsoft to deliver electricity from its fusion plant starting in 2028, and a customer agreement with Nucor to develop a power plant in the 2030s.

Helion has just started operating its seventh generation prototype, Polaris, which is expected to demonstrate the first electricity produced from fusion.

“We are on the brink of delivering a transformative energy solution that can meet the world’s increasing electricity demands while preserving U.S. energy leadership,” said co-founder and CEO David Kirtley.

Fusion funding

Helion’s new round is the second-largest in the fusion sector since the start of last year, per Crunchbase data.

Last October, Pacific Fusion, a startup attempting to create a nuclear fusion-based energy source, raised more than $900 million in a Series A led by General Catalyst. The funding does depend on the company hitting certain milestones.

Since the beginning of 2024, there have only been about two dozen deals of $200,000 or more for fusion-related startups, raising just more than $7 billion.