How much horsepower can humans generate on a bike

I'm working on a project that needs the data on how much horsepower a human can produce/generate on a bike.

I want to see how much energy a:

11/12 year old could produce while biking casually for an hour _______ MH
12/13 year old could produce while biking casually for an hour _______ MH
30/40 year old could produce while biking casually for an hour _______ MH

Thank you.

MH means what?

depends on speed. Picking the low speed number below, 175 watt is 0.37 HP. In an hour that is 175 joules of energy.

You can't break it down by age that easily, it depends on the shape the person is in , and the speed.

reference:
175 W for a 90 kg bike + rider to go 9 m/s (20 mph or 32 km/h) on the flat.
300 W for a 90 kg bike + rider at 11 m/s (25 mph or 40 km/h) on the flat