At the last company I worked for, which was a manufacturing facility. They installed a giant flywheel as a line conditioning device. (We manufactured NAS, and i

At the last company I worked for, which was a manufacturing facility. They installed a giant flywheel as a line conditioning device. (We manufactured NAS, and it is terribly costly when a power outage interrupts 5 days worth of testing forcing you to start over). I think it gave us about 17-18 seconds of power, in the event of any brief interruptions in power (Most of the outages we received were 1-2 seconds in length)