Realta Fusion generates electricity directly from a fusion reaction, an apparent first

In a significant advancement for the fusion energy sector, Realta Fusion has successfully demonstrated the ability to generate electricity directly from a fusion reaction. This breakthrough was achieved during an experiment on June 19, where the Wisconsin-based startup powered a lightbulb using electricity harvested from its demonstration fusion device, named WHAM. Realta Fusion claims to be the first private company to showcase this capability publicly. Kieran Furlong, co-founder and CEO of Realta Fusion, emphasized the implications of this achievement, stating, "We can take power from a plasma." He highlighted that this milestone illustrates the potential of fusion energy to revolutionize electricity generation. The startup plans to leverage direct electricity conversion to heat the plasma within its reactor, a process that demands considerable energy. Furlong estimates that this method of direct conversion operates at around 90% efficiency, significantly outpacing the approximately 33% efficiency of steam turbines used in conventional fission reactors. The ability to harvest more energy directly from fusion reactions could accelerate Realta Fusion's path to profitability, as all power plants, including fusion reactors, consume energy for their operation. A major hurdle for fusion startups has been the challenge of designing reactors that produce more energy than they consume. The efficiency gained from direct energy conversion is expected to ease this challenge. Notably, around 20% of the energy from fusion reactions utilizing deuterium-tritium—fuel that Realta intends to use in its commercial reactors—is released as charged helium nuclei, known as alpha particles. Realta Fusion has developed a prototype electricity converter attached to its reactor, allowing it to harvest enough alpha power to generate several amps of electricity at 100 volts, sufficient to illuminate multiple lightbulbs. On a larger commercial scale, these direct energy converters are anticipated to provide enough energy to effectively heat the plasma. Furlong explained that this approach enables a form of energy recirculation, which could increase the total output of a commercial power plant by 20% to 30%. He likened the concept to "spinning a flywheel of electricity," which he believes is highly advantageous for energy generation. While Realta Fusion is the first to demonstrate direct energy conversion publicly, it is not alone in this pursuit; Helion, another startup supported by Sam Altman, also aims to incorporate this technology in its designs, though it has yet to showcase it. Realta Fusion previously secured $36 million in a Series A funding round led by Future Ventures in 2025 and is currently working on securing additional funding to further its initiatives.