A private company betting on an innovative fusion technology announced today that its latest device can sustain high temperatures for long reaction times—a major step toward a reactor capable of producing more fusion energy than is consumed by the device. The company, TAE Technologies, is still far from that goal, which huge government efforts are also pushing toward. But its achievements so far have drawn $880 million in investment—more than any other private fusion company. The company also announced plans to scale up to a larger machine, which it hopes will reach fusion conditions by 2025.