In the Marvel Cinematic Universe (MCU), the Arc reactor provides nearly unlimited power to Iron Man's armor. The Tesseract cube technology has been reproduced to provide power even though the reactor is only the size of Tony Stark's palm. In the real world, the ARC (Affordable, Robust, Compact) reactor will be built in Virginia, United States to provide nearly unlimited clean electricity.
Deuterium and tritium fuels will be used to produce clean energy with only helium and neutrons as byproducts without radioactive waste. CFS is currently building the SPARC tokamak, which will be a nuclear fusion chamber at temperatures hotter than the sun.
The reactor will be built by Commonwealth Fusion Systems (CFS) based on nuclear fusion technology developed by the Massachusetts Institute of Technology (MIT). When operational by the early 2030s, it will generate 400 megawatts of energy.
Electric power generated using nuclear fusion has already been successfully achieved by scientists at the United States Department of Energy in 2022. In addition to the United States, China, South Korea and the EU are also actively developing their own tokamak technology. 1 gram of fuel can produce the same energy as 10 tons of coal but without carbon emissions.