The Demonstration Harnessed the Kinetic Energy in Fusion Plasma to Increase the Electrical Output By A Fusion Machine
Earlier this month, The Fusion Report covered a release from Realta Fusion on their recent publication of the plans for their Hammir-DT fusion plant design. One of the key details of that plan was to utilize an approach known as direct energy conversion to convert the energy of charged particles produced by a fusion reaction into electricity. The potential benefit of the approach is that a fusion machine would not lose the roughly 55% of the energy produced by a fusion reaction during the conversion of thermal energy into electricity, as is done with the thermal cycle approach utilized by most electrical power generation plants, whether fossil fuels, fission, or fusion powered. Yesterday (June 29, 2026), Realta Fusion demonstrated their direct energy conversion (DEC) approach at the Wisconsin HTS axisymmetric mirror (WHAM) fusion machine at the University of Wisconsin-Madison (UW-M). One of the benefits of the DEC approach is it can not only work for deuterium-tritium (D-T) reactions, but also for other fusion fuel cycles such as catalyzed deuterium-deuterium (DD) or deuterium-helium-3 (D-He3), both of which have the benefit of being aneutronic (i.e., not producing high energy neutrons). The press release issued by Realta Fusion is given below.
REALTA FUSION BECOMES FIRST COMMERCIAL FUSION COMPANY TO CONVERT PLASMA ENERGY INTO ELECTRICITY
Realta’s Successful Direct Energy Conversion (DEC) of Plasma Kinetic Energy Into Electricity Shows Credible Path to Low-Cost Power from Magnetic Mirror Fusion Machines
Madison, Wis. – June 30, 2026 – Realta Fusion, the world’s leading magnetic mirror fusion energy company, today announced the first ever demonstration of direct energy conversion (DEC) of plasma kinetic energy into electricity by a commercial fusion energy company.
In this first-of-a-kind achievement, Realta successfully demonstrated the ability to draw multiple amps of current at around 100 volts and provide enough electrical power to illuminate several light bulbs.
“People have been talking a big game about DEC for years, so we just went out and did it,” said Realta CEO Kieran Furlong. “We’re the first private fusion company to achieve DEC of plasma kinetic energy into electricity on a real fusion machine.”
Realta first installed and demonstrated its direct energy converter on the Wisconsin HTS Axisymmetric Mirror (WHAM) – the experimental fusion machine it operates in collaboration with the University of Wisconsin-Madison – on June 19th, 2026. The converter works by slowing down charged particles at one end of the machine, which builds up an electrical potential or voltage to drive an electrical current.
“This is a first demonstration, but still a meaningful technical milestone and proof-of-concept that DEC can be done at a scale to light things up,” said Dr. Derek Sutherland, Realta’s Chief Scientific Officer. “While we’ve demonstrated DEC works on WHAM, this is not yet a demonstration of net-electricity or a large-scale conversion of fusion power directly into electricity. Those are milestones for our future fusion machines.”
The use of DEC in fusion machines is especially meaningful for increasing the efficiency of the system. For the first-generation fusion power plants Realta expects to build starting in the mid-2030s, 80% of the fusion power would come from running a traditional thermal cycle operating at up to 45% efficiency while the remaining 20% would come from DEC operating at over 90% efficiency. The boost provided by DEC would offset all the energy Realta injects into its plasma to start up and sustain fusion plasma conditions, thereby raising the energy gain and lowering the cost per kilowatt hour by at least 10-20%.
DEC was first proposed by Lawrence Livermore National Laboratory’s Dr. Richard Post in 1974. While DEC has been shown a handful of times in academic and national laboratory settings, including the “venetian blind” converter in the 1970s, TMX in the 1980s, and GAMMA 10 as recently as 2008, no commercial fusion company has ever demonstrated that it can apply DEC to a fusion plasma prior to Realta.
Single-stage direct energy converter on WHAM. Upper left: Direct energy converter installed in the center of the end-ring in CAD. Upper right: Assembled system ready for install on WHAM. Lower left and right: Zoomed in pictures of the direct energy converter assembly head on and at an angle showing the three-layer grids used for this first prototype. Special thanks to Dmitry Yakovlev (UW-Madison), Tucker Peterson (UW-Madison) and Ty Omark (Realta Fusion) for their work on the converter.
Conclusion: Why This Demonstration is Important
The conversion of heat energy into electricity has been a known scientific principle for over 200 years, with practical and commercial applications in power plants beginning to appear 144 years ago with Thomas Edison’s (London, England) Holborn Viaduct Power Station being built in January 12th, 1882. Since then, the thermal cycle approach has been utilized in most commercial power plants, except for renewable sources such as hydroelectric, photoelectric solar, or wind power which directly convert kinetic or solar energy into electricity. The concept of direct energy conversion (DEC) has been around since the 1970s, converting heat or fusion plasma directly into electricity without the need for intermediate thermal to mechanical turbine conversion, but it was not actually demonstrated until yesterday.
For fusion energy, DEC is important because it bypasses the use of heat generated by fusion and directly utilizes the kinetic energy of charged particles to create electricity. The result is potentially significantly higher efficiency in the electrical conversion cycle than is possible using thermal conversion approaches, which tend to be no more than 55% efficient, and which require water-based cooling approaches. The benefit of DEC besides more efficient power plants is significantly smaller power plant designs, due to the elimination of cooling towers needed for thermal cycle electrical generation power plants. Both Realta Fusion and Helion Energy are championing the approach of DEC for use in the commercial fusion power plants.
