[talldrinkofwhat]

P=IV (power = current * voltage)

Lipos -> 3.7V nominal once you're in the meat of it. 100uW -> 27uA @3.7V, which is a __VERY__ generous current budget with modern microcontrollers and effective use of sleep modes.

AAA Cells -> 1200mAH @27uA -> 5rs

AA Cells -> 2200mAH @27uA -> 9.3yrs

C Cells -> 9000mAH @27uA -> 38yrs

Then just remember that this thing is smaller than all of those, has no self discharge which typically steals 2-3% of the battery capacity year-over-year, and that with lipo's you can't use the last chunk of nameplate capacity due to precipitous voltage drop at the end of the discharge curve.