Helion Energy, the Everett-headquartered fusion startup, has expanded from 80 employees to 800 over four years and opened a new downtown Seattle office for its business team.

CEO David Kirtley announced the Seattle office opening on LinkedIn on Tuesday, Sept. 8, the Lynnwood Times reported. Kirtley said the office will support further company-wide growth. The specific address was not disclosed.

Gov. Bob Ferguson praised the expansion on X, noting that Helion now employs workers across three Washington locations: Everett, Seattle and Chelan County. Ferguson said Washington's fusion industry leads globally.

Helion moved its headquarters to Everett around 2022 after being founded in 2013. The company has since become one of the region's fastest-growing employers, raising more than $1.5 billion in total investment. A $465 million Series G round earlier in 2026 valued the company at $15.5 billion.

The workforce growth ties directly to Helion's biggest project: the Orion facility in Malaga, Chelan County. The plant aims to deliver at least 50 megawatts of electricity to Microsoft data centers by the end of 2028 under a power purchase agreement signed in 2023.

Construction has hit several milestones. In June, Helion became the first company in the world to receive Washington Department of Health radioactive materials and air emissions licenses for a fusion plant, 425 Business reported. Assembly and office-building construction at the Orion site were complete as of June, with earthwork on the generator building underway since spring.

"We are extremely proud to be granted these licenses from the Washington DOH, making us the first company in the world with the regulatory approvals in place for fusion power plant operations," Kirtley said in June when the licenses were announced.

Helion also secured a transmission interconnection agreement with Chelan County Public Utility District, described as the first such deal for a fusion power plant.

Significant technical hurdles remain before any fusion plant can deliver reliable grid power, the Lynnwood Times reported. Washington state legislation in 2024 and 2025 classified fusion as clean energy, separate from nuclear fission, to ease permitting.

Helion is not the only fusion company in the region. Everett-based Zap Energy is also developing fusion technology, contributing to Washington's growing cluster of private fusion startups.

Helion's next major deadline is its 2028 target to begin delivering power from the Orion plant to Microsoft.