For Realta Fusion, the hard part is over: they’ve successfully powered a lightbulb using electricity harvested directly from their demonstration fusion device. This marks a significant milestone and suggests that direct energy conversion could drastically boost efficiency.

“We can take power from a plasma,” says Kieran Furlong, co-founder and CEO of Realta Fusion. The successful experiment showcases the potential for more efficient use of fusion reactions. By comparison, today’s fission reactors are only about 33% efficient in converting energy to electricity.

Direct conversion is estimated to be around 90% efficient, meaning it converts most of the potential energy into usable power. This efficiency boost could make commercial-scale operation more feasible and profitable. Realta plans to use this technology to heat their reactor’s plasma, potentially increasing output by 20% to 30%. “Spinning a flywheel of electricity is very beneficial,” Furlong notes.

Other startups are also exploring direct energy conversion, including Helion, backed by Sam Altman. While Realta has demonstrated it publicly, the technology could revolutionize how we generate and use fusion power.