Zap Energy announced April 23 that it has reached 1-3 keV plasma electron temperatures—roughly the equivalent of 11 to 37 million degrees Celsius—using its sheared-flow-stabilized Z-pinch approach to fusion. Reaching temperatures above that of the sun’s core (which is 10 million degrees Celsius temperature) is just one hurdle required before any fusion confinement concept can realistically pursue net gain and fusion energy.

Realta Fusion of Madison, Wis., and Zap Energy of Everett, Wash., are just two of the eight fusion developers selected by the Department of Energy for funding last week under the public-private Milestone-Based Fusion Development Program. They are the two companies with power plant concepts that don’t fit neatly into established fusion confinement categories. As energy secretary Jennifer Granholm said when she announced the awardees, “Some are working on more technically mature approaches like tokamaks and stellarators and laser inertial fusion, and others are working on innovative concepts with lower technical maturity like mirror and Z-pinch, which could lead to more compact and lower cost systems.”

Zap Energy has created the first plasmas in its FuZE-Q machine—the company’s fourth prototype machine and the one it hopes will demonstrate a net energy gain from a Z-pinch fusion plasma just one millimeter in diameter and half a meter long. Zap Energy announced that engineering achievement and the close of $160 million in Series C funding in late June.