Sam Altman-Backed Fusion Startup Helion Reaches $15.5 Billion Valuation, Targets Microsoft Power Supply in 2028
Helion is a U.S. nuclear fusion startup backed by OpenAI CEO Sam Altman that is seeking to move fusion from the experimental stage to commercial power generation. As generative AI drives up data-center electricity demand, access to reliable, low-carbon energy has become a key constraint on AI infrastructure expansion for technology companies including Microsoft.
Helion has completed a $465 million Series G funding round, lifting its valuation to $15.5 billion. Under a power purchase agreement with Microsoft, the company plans to begin supplying commercial fusion power in 2028 to support Microsoft’s AI data centers. The timeline will also be an important test of whether fusion technology can be commercialized on schedule.
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The history behind this eventOpenAI in Talks for Helion Fusion Power Deal as Sam Altman Leaves Board to Avoid Conflict
OpenAI is seeking stable, long-term and low-carbon power supplies to support the rapid expansion of its AI computing capacity and data centers. Fusion startup Helion Energy has close ties to OpenAI CEO Sam Altman, who has invested in the company for years. A potential deal therefore raises corporate-governance and conflict-of-interest concerns.
OpenAI is in talks with Helion over a large-scale power purchase agreement that would provide up to 50 GW of fusion generation capacity by 2035. The deal’s value and signing date have not been disclosed. Altman has resigned from Helion’s board to avoid a conflict in the decision-making process, though his personal financial interest remains under external scrutiny.
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