Superconducting magnetic energy
95% of electrical energy can be stored in the magnetic field produced by a current in a super-cooled coil at -269oC. The superconductor has no resistance so the electricity can keep flowing loss free for ever.
The process is costly and not yet fully developed. It is used for evening out power supplies.
|a project funded by the U.S. Department of Energy (DOE) could pave the way for SMES technology that offers megawatt hours of energy storage. More ...|