Using some conversions from an internet site, one AA battery is 1.3e4 Joules and a human requires 8.4e6 Joules per day, so about 133 seconds of energy saved per

Using some conversions from an internet site, one AA battery is 1.3e4 Joules and a human requires 8.4e6 Joules per day, so about 133 seconds of energy saved per 6 months of novel, or two lost seconds of calorie burning exercise every three days. (Lots of sketchy napkin math here)