Signal Realta Fusion powers light bulbs with 90% efficient direct plasma energy conversion (WHAM device)

Summary

On June 19, 2026, Wisconsin-based Realta Fusion announced it had powered several light bulbs by drawing multiple amps of current at roughly 100 volts, harvested directly from its Wisconsin HTS Axisymmetric Mirror (WHAM) demonstration fusion device, operated in collaboration with the University of Wisconsin-Madison, using an electrostatic direct energy conversion (DEC) method that slows exiting charged particles to convert their kinetic energy into electricity. CEO Kieran Furlong estimates the DEC process is about 90% efficient, versus roughly 33% for steam turbines in today's fission plants, and envisions future commercial plants generating 80% of power via a traditional thermal cycle (up to 45% efficient) and 20% via DEC (over 90% efficient), potentially cutting cost per kilowatt-hour by 10-20% and boosting total plant output 20-30% through recirculating electricity to sustain the plasma. Chief Scientific Officer Derek Sutherland cautioned this is "not yet a demonstration of net-electricity or a large-scale conversion of fusion power directly into electricity," since the output was only hundreds of watts and most captured power came from energy fed into the plasma rather than fusion reactions themselves. Direct energy conversion was first proposed by physicist Richard Post in the 1970s, and Sam Altman-backed rival Helion is also pursuing the technology as central to its plans but has not yet demonstrated it publicly. Realta believes this is the first public demonstration of the concept by a private commercial fusion company.