Storing power for critical loads

The operation of systems for superconducting magnetic-energy storage (SMES) is explained. The original goal was systems storing thousands of megawatts of back-up electricity for several hours at a time, to help utilities meet peak power demands. The first commercially available unit rapidly stores and delivers much less electricity over much briefer periods-megawatts for seconds only. It excels in its handling of power glitches, an increasingly expensive problem in industrial applications of digital control equipment, and for other electronic equipment. The advantages of SMES for these applications are examined, and some field test results are discussed.<>