Has fusion ever made more energy than it consumes?
 
 
 

In the H bomb as well as the sun, fusion has been shown to work as a source of energy from matter. To make fusion useful for humans on earth the process has to be controlled, and reduced vastly in scale. Contriving this introduces its own problems, as one tries to design the cheapest smallest system which works.

So far, the experimental development programme of man-made fusion has not made more energy than consumed. Nor has it worked to produce more power than consumed at any instant.

The experimental programmes on JET and TFTR have come closest to "breakeven" - more power out of the plasma than goes in. The record to date is on JET, where 16 MW of fusion power has been produced for 1-2 s. The injected power from plasma heating at that time was about 24 MW, so the power amplification (Q) of the plasma was 0.6, i.e no net gain.

Of course, to run the plasma and experimental facility, at that time, the site electric power requirement was ~ 100 MW, so for any successful fusion plant Q has to be much larger than in JET.