We have controlled fusion in labs, but it takes more energy to start up than what you get out of it. The longer you can sustain the fusion reaction, the more yo

We have controlled fusion in labs, but it takes more energy to start up than what you get out of it. The longer you can sustain the fusion reaction, the more you can get out of it. They did it for 5 seconds, which is longer than anyone else, but still a net negative. Predictions about the future of fusion are notoriously difficult to make.