Realta Fusion generates electricity directly from a fusion reaction, an apparent first
Wisconsin-based startup Realta Fusion announced it successfully powered a lightbulb using electricity harvested directly from its WHAM demonstration fusion device on June 19, claiming to be the first private company to publicly demonstrate such a feat.
Realta Fusion, a nuclear fusion startup based in Wisconsin, announced that an experiment conducted on June 19 successfully powered a lightbulb using electricity harvested directly from WHAM, its demonstration fusion device. The company believes it is the first private firm to publicly demonstrate such a milestone.
Direct electricity conversion from fusion reactions is more efficient than the traditional approach of using heat to produce steam for turbines. Kieran Furlong, co-founder and CEO of Realta Fusion, estimates direct conversion is about 90% efficient, compared to around 33% for steam turbines in today's fission reactors.
About 20% of the energy from deuterium-tritium fusion reactions—the type Realta plans to use—are charged helium nuclei known as alpha particles. The startup built a prototype electricity converter attached to the end of its reactor, which harvested enough “alpha power” to generate multiple amps of electricity at 100 volts, lighting a few lightbulbs.
In a commercial-scale power plant, these direct energy converters should provide enough electricity to heat the plasma. Furlong estimates this circularity could boost a plant's total output by 20% to 30%.
Realta Fusion previously raised $36 million in a Series A round led by Future Ventures in 2025 and is currently raising a new round. While Realta is the first to demonstrate direct energy conversion publicly, other startups like Helion also plan to use the technology but have yet to show it.
