When British physicist Arthur Stanley Eddington first proposed in the 1920s that the sun and stars were powered by the fusion of hydrogen into helium, his idea sparked a rush of research and speculation into the possibility of bringing this energy source to earth. It was not long before journalists and pulp fiction authors were predicting a time, surely not far away, when the world would be powered by simple fusion reactors requiring nothing more than abundant hydrogen from water.
Practical, economic generation from fusion is not yet here, and it’s a solid bet that it will not arrive on the grid before the 2030s. Yet that reality is considerably closer than many people realize. As the result of decades of scientific advancement by the U.S. and other nations, most of the key physics questions behind fusion have been answered. Meanwhile, the first reactor that should achieve “burn”—that is, self-sustaining fusion—is currently under construction in France, with operations set to begin within the next few years.