The fusion industry has spent decades proving the physics. The next challenge is building the supply chain to match. For pulsed power fusion, an approach backed by roughly $2 billion in private capital, that starts with the capacitor. Pulsed power fusion machines require tens of thousands of them per facility, and the current supply base wasn't built to operate at that scale.
The Impedance-Matched Marx Generator (IMG) represents a fundamental architecture shift for pulsed power fusion. Traditional Marx generators require multiple pulse compression stages between the capacitor bank and the fusion target, each one dissipating energy along the way. Sandia's Z Machine delivers only about 8% of its stored energy to the target.
IMGs eliminate three of those four stages. Their building block is the “brick”: two small capacitors and a single switch that fire sequentially, launching a coherent electromagnetic wave along an internal transmission line. The result is roughly 90% energy delivery efficiency and 6x lower stored energy requirements. The same architecture that improves efficiency also multiplies the number of capacitors each machine needs, and that's where the supply chain problem begins.
The Scale Problem
The Z Machine uses 2,160 large capacitors. IMG-based machines use tens of thousands of smaller ones. Pacific Fusion’s 156-module demonstration system contains approximately 50,000 capacitors. Sandia’s conceptual Jupiter machine, designed for high-yield fusion experiments, specifies 352,800. The architecture that makes commercial fusion plausible also multiplies component demand by two to three orders of magnitude.
And it’s not just Pacific Fusion. Roughly $2 billion in private capital has converged around inertial confinement fusion in the past three years, and each major player is generating substantial capacitor demand. On the IMG side, Fuse Energy Technologies built TITAN, a 14-stage IMG whose 6-stage testbed achieved 330 GW peak power, and plans a 16-module Z-Star system around 2027. Xcimer Energy uses Marx generators to charge pulse-forming lines for its excimer laser architecture.
On the laser-driven side, Inertia Enterprises ($450M Series A, February 2026) is building a laser system with roughly 1,000 modular laser units. Focused Energy pursues proton fast ignition and has partnered with Amplitude in a laser development agreement.
The pattern is consistent across every approach. Regardless of the driver architecture, the energy that reaches the fusion target originates in a capacitor bank. Every one of those capacitors must survive millions of charge-discharge cycles at extreme voltages.
The Dielectric Constraint
The dominant dielectric material in today’s pulsed power capacitors is biaxially oriented polypropylene (BOPP). It’s mature, well-characterized, and offers high breakdown strength with good self-healing characteristics. For laboratory-scale applications like the Z Machine’s mission profile of roughly 200 shots per year, BOPP performs reliably.
The limitations emerge when commercial fusion demands are applied. BOPP stores approximately 2.4 J/cc with a practical operating temperature ceiling around 85°C. Above that threshold, the material derates — a real constraint in repetitive-pulse environments where self-heating accumulates between shots. For fusion machines that need to fire at Hz rates over multi-decade plant lifetimes, those limitations compound into system-level problems: physically larger capacitor banks, more cooling infrastructure, shorter maintenance intervals, and higher capital costs.
A 2025 IEEE paper quantifies the gap. For a facility firing 200 shots per year, current capacitor lifetimes of approximately 17,000 shots are adequate. For Hz-rate commercial operation requiring millions of shots, energy storage costs must decrease 5–10x and component lifetimes must increase roughly 1,000x. The paper explicitly identifies advanced dielectrics capable of operating at hundreds of kilovolts under repetitive discharge as a critical development need.
A Thin Manufacturer Base and a Geopolitical Problem
The qualified U.S. manufacturer base for high-voltage pulsed power capacitors is concentrated in a small number of firms, principally General Atomics Electromagnetic Systems. Internationally, ITOPP/ALCEN in France and API Capacitors in the UK serve the market. General Atomics’ largest production contract was 2,500 units for the Z Refurbishment. The jump from thousands to tens of thousands of capacitors per facility represents a manufacturing scale-up the existing base is not configured to deliver.
The material supply chain compounds the problem. Most capacitor-grade polypropylene film is sourced from China, leaving fusion developers exposed to geopolitical disruption and long lead times as they move toward funded construction programs. According to the Fusion Industry Association's 2025 supply chain report, concern about supplier availability rises to 63% when fusion companies consider future commercial-scale needs.
Federal policy is beginning to respond. FY26 appropriations language directed continued support for U.S.-based production of nanolayer capacitor film. The proposed Fusion Manufacturing Parity Act and the expansion of 45X advanced manufacturing tax credits signal that Washington sees domestic component manufacturing as a prerequisite for fusion commercialization, not an afterthought. But policy signals alone don’t produce hardware.
Federal policy is beginning to respond. The proposed Fusion Manufacturing Parity Act and the expansion of 45X advanced manufacturing tax credits signal that Washington sees domestic component manufacturing as a prerequisite for fusion commercialization. However, policy signals alone don't produce hardware.
New Materials, New Partnerships
A handful of companies are working to close the gap between what fusion developers need and what the current supply base can deliver. Ohio-based Peak Nano and Florida-based E&P Technologies recently announced a partnership to co-develop high-energy-density capacitors using Peak Nano's nanolayered dielectric film. The collaboration pairs an advanced materials platform with up to 4x the energy density of BOPP at operating temperatures up to 125°C with automated capacitor manufacturing and qualification expertise, including direct program experience from Xcimer Energy and Blue Origin.
It’s one example of a broader trend the fusion industry will need more of: specialized materials companies and precision manufacturers forming integrated partnerships to produce qualified components.
The Bigger Picture
The timeline for major component procurement decisions is compressing. The fusion supply chain story is not about any single component or any single partnership. It’s about whether the industrial base can scale in parallel with the fusion machines themselves.
Capacitors for pulsed power systems are a useful lens for understanding that challenge because they sit at the intersection of materials science, precision manufacturing, and geopolitical supply chain risk. All three are pressure points that will determine how fast fusion moves towards scalable power plants.
The fusion industry has spent the last several years proving the physics. The next phase is proving the supply chain.
