Martin Greenwald stands in a windowless control room at Massachusetts Institute of Technology, holding a heavy, thick cable in his left hand. Pinched between his right index finger and thumb is a thin strip of dull-brown metal tape. That strip can carry as much electrical current as the hefty cable, he explains, and could enable scientists to build a mighty machine they’ve been dreaming about for decades.
By winding spool after spool of the yttrium barium copper oxide tape into some of the strongest magnets on Earth, scientists at the MIT Plasma Science & Fusion Center hope to build a nuclear fusion reactor. If all goes well, these ultrastrong magnets will lasso and wrangle a roughly 100 million ºC hydrogen plasma, driving its protons to fuse and releasing tremendous amounts of energy over sustainable time periods. Commonwealth Fusion Systems, a spin-off company from this MIT project, hopes to turn the research into a commercial reactor to produce carbon-free electricity.
“Fusion has the features you want in the ideal energy source,” Dennis Whyte, director of the MIT center and a cofounder of Commonwealth Systems, says. The fuels are abundant, and the process is safer than nuclear fission because there is no risk of a meltdown. Fusion reactors should use less land than renewable energy technologies such as solar panels and provide continuous power as coal plants do but without greenhouse gas emissions.