/diy/ - Do It Yourself

Would it be possible to incorporate a massive flywheel as a power backup system in a home?
Imagine using a small electric motor to slowly input electricity into a huge flywheel setup in your attic or basement. The RPM can be monitored electronically and once you hit a threshold you would stop feeding the flywheel. It could be set to slowly "rev" up over many months/years and maintain a stable RPM while only occasionally siphoning power from the mains to charge it.
Once your power goes out you could have a break flip and then the flywheel begins to feed an electric generator in your home to power certain devices.
No need to worry about batteries or fuel for a generator, it would just hum along in the normally unused space in your home until you needed it. It could be incredibly large and heavy, since it's not in the way of anything. On top of that it would never need to be removed, maybe just suspended for maintenance on bearings or the electrical systems. It won't last as long as a generator but most power outages don't last more than a few hours or maybe days depending on the circumstances.
Is this a dumb idea? Anyone ever look into a similar system?