When I was at Peloton a long time ago, someone proposed an April Fools’ joke where we could announce a dynamo add-on that would let you power your house from your bike.
The math isn’t as bad as you might think: 200Wh (about a 60 min, somewhat intense ride) seems to be about 20 minutes for a H/B100. Still 3x, but not bad at all!
I remember the idea being dismissed quickly because people would likely actually want it.