I've read that a typical human-powered bicycle power generator generates around 100W. For the same amount of effort, the bike travels probably around 20k/h on a road. Does that mean it requires 100Wh for a ~70kg load to travel 20km? If so, does it mean that a 70kg-machine with wheels (e.g., a RC car) requires 125Wh (100Wh / 0.8 assuming 80% motor efficiency) to travel 20km? But how well can one translate the energy human expends when cycling into energy a machine with wheels expends?