Fusion energy is not something you hear about every day, yet it has the ability to shape how the world is powered. Helion Energy, a Washington-based fusion firm, is working to make this long-discussed concept a reality. While fusion has long been regarded as an ambitious, seemingly unachievable objective, Helion has successfully balanced advances and hurdles, earning the trust of high-profile investors along the way. The business recently raised $425 million in its Series F fundraising round.
One of the biggest hurdles for Helion lies in securing the specialized components needed to build its reactors. Its latest prototype, Polaris, houses approximately 50,000 pulse-power semiconductors—critical elements that have proven difficult to source, similar to supply chain issues faced in AI and semiconductor industries. To mitigate this, Helion is shifting more of its manufacturing in-house, aiming to produce capacitors and other key parts more quickly to accelerate development.
Despite these challenges, CEO David Kirtley remains confident that Helion will meet its 2028 deadline to supply electricity to Microsoft. The company has already begun work on site planning and permitting for the facility, a crucial step toward integrating fusion energy into the grid.
A Different Approach to Fusion
Unlike many competitors focused on traditional magnetic confinement or laser-based inertial fusion, Helion is betting on a field-reversed configuration (FRC) reactor. This approach uses powerful magnets to guide and compress plasma, creating conditions necessary for fusion. Rather than relying on steam turbines to convert heat into electricity, Helion’s design aims to extract power directly from the reaction, making the process more efficient and potentially more scalable.
The company’s long-term vision includes commercial reactors capable of generating 50 megawatts each, with multiple reactors operating within a single power plant. Additionally, Helion is working on increasing its pulse rates, a crucial factor in achieving sustained energy output and making fusion a viable power source for industrial applications.
Helion’s funding round saw participation from new investors such as Lightspeed Venture Partners, SoftBank Vision Fund 2, and a major university endowment. Existing investors, including Sam Altman, Mithril Capital, Capricorn Investment Group, Dustin Moskovitz through Good Ventures Foundation, and Nucor, also reinforced their commitment to the company’s future.
“We brought on several new investors this round… who completed extensive due diligence in our science, engineering, and business,” Helion stated in its funding announcement. “Their decision to invest in Helion reflects how much we have built, how fast we have done it, and their belief in Helion’s approach to getting fusion to the grid as quickly as possible.”
For OpenAI CEO Sam Altman, who chairs Helion’s board, this investment aligns with his broader vision of an AI-driven future supported by abundant, sustainable energy. Altman has been a strong advocate of Helion, personally backing the company in multiple funding rounds. “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 Helion co-founder and CEO David Kirtley.
Scaling Up for the Future
A major portion of Helion’s new funding will go toward addressing supply chain bottlenecks and expanding in-house manufacturing capabilities. The company aims to reduce dependence on external suppliers for critical components like capacitors and magnetic coils, which have historically required long lead times.
“Our goal is to go from waiting three years for a supplier to give us capacitors to us making our own capacitors but faster, so now we can make them in a year or less,” Kirtley explained. Additionally, Helion is working on obtaining permits and grid interconnection for its Microsoft facility, a process that can take years to complete.
Looking ahead, Helion plans to build a much larger 500MW fusion power plant for steel manufacturer Nucor, expected to be operational in the 2030s. While scaling from a 50MW reactor to a 500MW facility presents significant engineering challenges, the company remains committed to its aggressive timeline.
Fusion energy remains one of the most challenging frontiers in clean energy, and Helion has yet to achieve net-positive energy production—a milestone crucial to proving its technology’s feasibility. However, investors remain optimistic about Helion’s leadership and progress.
“After extensive due diligence, we’re very confident in Helion’s technology and leadership as the company moves from research and development into commercial production,” said Lightspeed Venture Partners co-founder Ravi Mhatre.
While the path to commercial fusion is uncertain, the company’s ability to gain big alliances and investor confidence indicates that it is still one of the most promising competitors in the area. It remains to be seen whether it can make its 2028 commitment to Microsoft, but for the time being, Helion is a brand to keep an eye on in the future.