Pacific Fusion hits power milestone, unlocks $1B+ funding tranche

On Tuesday, Pacific Fusion revealed its latest pulser module prototype, a development that has unlocked a new tranche of the company’s Series A funding round. According to the company, the total Series A funding exceeds $1 billion. This tranche-based funding structure, more common in the biotechnology sector, allows the startup to focus on technical milestones rather than continuous fundraising. Keith LeChien, the CTO of Pacific Fusion, stated: “It means that we can lean into the future without spending 20% to 50% time constantly looking for the next piece of capital.”

Pacific Fusion is pursuing inertial confinement, a fusion energy approach that uses high-energy electrical pulses to compress a small fuel target. To achieve this, the company’s planned demonstration device will require 156 full-size pulser modules to deliver precise electrical pulses, each lasting about 100 nanoseconds. The startup’s next challenge is scaling up from its subscale prototype to a full-size pulser module, which serves as the core component of the demonstration system. The recently tested prototype is about a third of the size of a full module and successfully released 440 gigawatts of peak power in an 80-nanosecond burst.

The architecture of the full-scale system relies on a highly modular design to ensure the capacitors release their energy at precisely the right moment to compress the fuel pellet:

• Each of the 156 pulser modules contains 32 circular stages.
• Each stage is ringed with 10 bricks.
• Each brick contains two capacitors to store power and one switch to release it.
• The tested prototype scaled this down to nine stages and 90 bricks.

Construction on the demonstration facility is expected to begin this summer. The company’s ultimate goal is to achieve facility breakeven, where the device generates more energy than the entire facility requires to operate. This differs from scientific breakeven—releasing more energy than was required to start the reaction—which has only been achieved and replicated using inertial confinement at the National Ignition Facility, a US government research lab hosted at the Lawrence Livermore National Laboratory. However, Pacific Fusion clarified that its demonstration device will not qualify as a power plant because it lacks a steam turbine.

Why it matters

The successful prototype test validates the company’s technical approach and secures the capital necessary to move from subscale testing to a full-scale demonstration facility, a critical step toward achieving facility breakeven.