In a significant step toward commercial fusion energy, researchers have subjected a prototype fusion platform to a barrage of powerful electrical pulses equivalent to twelve lightning strikes per minute. The successful test demonstrates the durability of core components designed to handle the extreme conditions inside a future fusion power plant, marking a critical advance in a design that sidesteps the need for massive, complex magnets.
The achievement, accomplished by private company Zap Energy on its Century test platform, involved sustaining more than 100 consecutive plasma discharges at a rate of 0.2 hertz. Each pulse carried up to 500 kiloamps of current—roughly 20 times the energy of a natural lightning bolt—into a compact vacuum chamber lined with flowing liquid metal. This sustained, high-frequency operation is vital for developing fusion systems that can eventually run continuously and deliver power to the grid. The results represent a 20-fold increase in the sustained average power compared to the system’s initial commissioning runs in 2024.
A Different Path to Fusion Power
The technology at the heart of the test is a sheared-flow-stabilized (SFS) Z-pinch. Unlike mainstream fusion approaches like tokamaks and stellarators, which rely on powerful, room-sized superconducting magnets to confine and control superheated plasma, a Z-pinch uses a powerful electrical current to generate its own magnetic field. This current simultaneously compresses and heats the plasma to fusion-relevant temperatures and pressures.
Historically, Z-pinch plasmas have been notoriously unstable, collapsing in fractions of a second. However, Zap Energy’s SFS configuration stabilizes the plasma by making it flow in a specific pattern where different layers move at different speeds. This “sheared flow” smooths out the instabilities that would otherwise extinguish the fusion reaction. By eliminating the need for expensive and complex magnet systems, the SFS Z-pinch approach could lead to smaller, simpler, and more economically viable fusion power plants.
Core System Components
The Century platform integrates several key technologies essential for a commercial power source. A repetitive pulsed power system delivers the high-current discharges, while durable electrodes are designed to withstand the extreme environment of the plasma chamber. During the record-setting operation, the system consumed a total of 57 kilowatts of input power, with 39 kilowatts delivered directly into the plasma itself, showcasing a significant improvement in energy efficiency and system integration.
Managing Extreme Heat with Liquid Metal
One of the greatest challenges in fusion energy is managing the immense heat generated by the plasma, which can be many times hotter than the core of the sun. The inner walls of a fusion reactor must endure this heat flux without melting or degrading. The Century platform addresses this by lining the plasma vessel with circulating liquid metal, a novel solution for heat absorption and transfer.
In the recent tests, the chamber walls were coated with flowing liquid bismuth. This 2,500-pound liquid bismuth circulation loop and a centrifugal liquid metal first wall absorb the intense energy from each plasma pulse and transfer it away. The heat is then moved to a 200-kilowatt air-cooled heat exchanger. This subsystem is not just for protection; in a future power plant, this captured heat would be used to boil water, drive turbines, and generate electricity. The successful operation of the liquid metal wall at a high repetition rate is a crucial proof-of-concept for this energy conversion process.
Sustained Operation and System Maturation
Achieving a high repetition rate is a fundamental requirement for a commercial fusion power plant, which must operate continuously rather than in short bursts. The ability to fire 12 pulses per minute for over 100 consecutive shots demonstrates the robustness and reliability of the Century platform’s integrated systems. According to Matthew Thompson, Zap Energy’s VP of Systems Engineering, these real-world tests provide a much clearer picture of what a commercial SFS Z-pinch power plant will look like.
The company reports that these experiments are already helping engineers identify and solve critical commercialization challenges. Since beginning operations, every key subsystem has been upgraded. In addition to the bismuth loop and heat exchanger, the platform features a redesigned nose cone tipped with liquid metal and an advanced cooling system for the cathode. The system has fired more than 10,000 shots to date, providing a wealth of data on the performance of a repetitively pulsed Z-pinch.
Future Outlook and Research Context
The successful sustained operation of the Century platform is a milestone for alternative fusion concepts. While much of the global fusion effort is focused on large-scale, internationally funded projects like ITER, private companies like Zap Energy are pursuing more nimble and potentially faster paths to commercialization. The company’s progress has been documented in peer-reviewed literature, with a recent paper in *Fusion Science and Technology* detailing the design and commissioning of the Century platform between June and October 2024.
Earlier in 2025, the U.S. Department of Energy certified a separate three-hour campaign on the platform, which involved over 1,000 consecutive plasma discharges at more than 100 kiloamps each. The company’s next steps will involve pushing for even higher repetition rates and power levels in future experimental campaigns. As these systems continue to mature, they offer the prospect of a more compact and economically competitive approach to achieving the long-held goal of clean, virtually limitless energy from nuclear fusion.