Helion Energy raises $465M Series G to build world's first fusion power plant for Microsoft by 2028

Helion Energy raises $465M Series G to build fusion power plant for Microsoft by 2028

Helion Energy has closed a $465 million Series G to fund construction of what it describes as the world's first commercial fusion power plant, built under a power purchase agreement with Microsoft targeting 2028 operations.

David Kirtley, Helion's co-founder and CEO, frames the raise as fuel for two parallel tracks: completing the company's seventh-generation Polaris fusion system in Washington State, and beginning construction of the eighth-generation Orion plant that will supply Microsoft. Helion is also scaling its manufacturing capacity by 60x to produce the electronics, capacitors, and modules the systems require.

“We raised a Series G, a $465,000,000 round. We've built now our seventh generation system called Polaris that does fusion here in Washington State. Our goal for the Microsoft program is to have our power plant built in 2028. We're 60x-ing our manufacturing line that produces the electronics and capacitors and modules for fusion right now.”

The technology

Most fusion approaches generate heat, then run that through steam turbines. Helion's bet is different: extracting electricity directly from the magnetic and electric energy of the fusion reaction itself, at efficiencies Kirtley puts at around 95%. At that extraction rate, the fusion reaction doesn't need to be as powerful, which allows for smaller, faster, and cheaper systems. Helion has built seven generations of hardware demonstrating this direct-extraction method, setting records for plasma temperature, pressure, and energy along the way.

Modular at 50 MW

The Microsoft plant will be a 50 megawatt facility. Kirtley says that is also the intended unit size for Helion's broader commercial model: modular 50 MW generators built in a factory, shipped by truck, delivered to site, and plugged in. A customer needing 500 MW buys ten units. He explicitly argues that building a single power plant and stopping would be a failure. The goal is mass production and global deployment at scale, modeled on how data centers are built out in modular, replicable blocks.

Construction and regulatory status

Ground was broken on the Microsoft plant site last year. Two buildings are complete, a third is under construction, and power infrastructure work begins this year. Environmental permits were granted in 2025.

On regulation, Kirtley says the ADVANCE Act, passed roughly 18 months ago, was a critical unlock. The Nuclear Regulatory Commission determined that fusion does not fall under its jurisdiction. Fusion is instead regulated at the state level, similarly to a hospital particle accelerator — still serious, still licensed, but with a permitting timeline of roughly one year rather than a decade. Helion has been state-licensed to handle the radioactive materials the process creates for several years.

Kirtley is clear that Helion's systems use no plutonium or uranium and cannot melt down or go critical, though the process does produce some radioactive byproducts that require careful handling.

The 2028 target is aggressive. Kirtley acknowledges the parallel workstreams are "a little crazy" but says the pace is necessary.