Realta Fusion generates electricity directly from fusion reaction, startup says
7 reported
Realta Fusion announced that an experiment on June 19 successfully powered a lightbulb using electricity harvested directly from its demonstration fusion device, WHAM. The Wisconsin-based startup believes it is the first private company to publicly demonstrate such a feat. The company plans to use direct electricity conversion to heat the plasma in its reactor, a process that requires significant energy. Co-founder and CEO Kieran Furlong told TechCrunch that direct conversion is about 90% efficient, compared to about 33% efficiency for steam turbines in today’s fission reactors. About 20% of the energy from deuterium-tritium fusion reactions are charged helium nuclei known as alpha particles. The startup built a prototype electricity converter attached to the end of its reactor, harvesting enough alpha power to generate multiple amps of electricity at 100 volts. Furlong estimates that circularity could boost a commercial scale power plant’s total output by 20% to 30%. Realta previously raised $36 million in a Series A led by Future Ventures in 2025 and is in the midst of raising a new round.
What’s reported
Realta Fusion conducted an experiment on June 19 that powered a lightbulb using electricity harvested directly from its WHAM demonstration fusion device.
The startup believes it is the first private company to publicly demonstrate direct electricity conversion from a fusion reaction.
Direct conversion is estimated by CEO Kieran Furlong to be about 90% efficient, compared to about 33% for steam turbines in fission reactors.
About 20% of energy from deuterium-tritium fusion reactions are alpha particles (charged helium nuclei).
The prototype converter generated multiple amps of electricity at 100 volts.
Furlong estimates circularity could boost a commercial plant’s total output by 20% to 30%.
Realta raised $36 million in a Series A led by Future Ventures in 2025 and is raising a new round.
Key figures
Kieran Furlong, co-founder and CEO of Realta Fusion
Future Ventures (investor in Series A)
Sam Altman (backer of Helion, another startup planning direct energy conversion)
Sources: TechCrunch
