Type One Energy has closed a $200 million Series B funding round to advance its stellarator technology and develop the first commercial fusion power plant at the Tennessee Valley Authority's Bull Run site in East Tennessee.

The Knoxville, Tennessee-based company, founded in 2019, will deploy the new capital across Project Infinity, its two-asset development program. Infinity One is a stellarator engineering prototype. Infinity Two is a planned 400 MWe commercial fusion power plant sited at Bull Run.

The round brings Type One Energy's cumulative funding to $400 million. Co-leads Breakthrough Energy Ventures (Bill Gates' climate-focused investment vehicle) and Clutterbuck Capital anchored the financing. New investors included Lowercarbon Capital, Siemens Energy Ventures and SiteGround Capital, with additional undisclosed participants.

What does Type One plan to build at Bull Run?

Infinity Two targets 400 MWe of baseload capacity from a stellarator geometry: external magnetic coils confine and heat ionized plasma in a twisted doughnut configuration. The design competes with the more widely known tokamak approach as developers race to commercialize fusion power.

The State of Tennessee issued Type One Energy its initial operating license for Project Infinity, the company said. That license clears a regulatory precondition for prototype operations at Bull Run.

Who else is in the consortium?

Type One is separately advancing a UK commercial fusion deployment through the Infinity Fusion Consortium. Partners on that project include Tokamak Energy, AECOM, Sheffield Forgemasters and Barclays. The consortium structure reflects the heavy industrial and financial alignment fusion developers now need to move from experimental physics to grid-scale engineering.

Chief Executive Officer Christofer Mowry said:

"The Series B financing enables us to remain focused on advancing our stellarator technology and Project Infinity design activities, while working with experienced industrial partners to deliver the first commercial fusion power plant at TVA's Bull Run site."

What milestones decide whether 400 MWe reaches the grid?

Three near-term checkpoints will determine whether Type One moves from prototype to construction:

• Initial operating license issued by Tennessee (announced with this round)
• Infinity One prototype demonstration: plasma confinement, heat extraction and tritium handling data
• Site-specific construction permit and TVA interconnection agreement for Infinity Two

Siemens Energy Ventures Partner Enrique Gonzalez Zanetich framed the industrial logic for joining the round:

"Fusion has the potential to become an important source of reliable, low-carbon energy at scale. This investment strengthens our position in the fusion field as we continue to explore the technologies and collaborations that can help advance commercialization."

Where does this leave the fusion financing cycle?

Type One's Series B lands inside a wider cluster of large fusion rounds as multiple private developers chase what the industry calls the "Holy Grail" of clean power. Funding alone does not close the physics-to-engineering gap that has delayed commercial fusion for decades — sustaining extreme plasma temperatures and achieving net energy gain remain the binding technical constraints.

The next decisive moment for Type One will be engineering performance from Infinity One at Bull Run. Watch for the Tennessee operating license's full scope and any TVA board action on an Infinity Two interconnection request — those two filings will set the timeline for the 400 MWe commercial plant.