[gruez]

> I'm impressed at the relatively high efficiency of the system. Pedalling at 150 watts and recovering 100 watts of electricity is higher than I would have expected from such a simple system.

It doesn't seem very surprising that motion can be converted to electricity at 66% efficiency. Normal power plants[1] can convert heat to electricity at 64% efficiency. It'll be much more interesting to see the end to end efficiency of this, ie. how many calories were consumed compared to electricity were generated.

[1] https://en.wikipedia.org/wiki/Combined_cycle_power_plant

[KennyBlanken]

A well-trained athlete can achieve about 33% efficiency in terms of calories used (not 'consumed' - we're talking about energy coming from glycogen and fat, in addition to whatever is eaten. The human digestive system can only process a couple hundred calories per hour before it starts diverting blood flow to the digestive system, which impairs athletic performance significantly.)