You can engineering estimate it in your head as one kilo-day per year and one kilo-hour in a century, and a nano 1e-9 is a kilo-kilo-kilo so to less than one si

You can engineering estimate it in your head as one kilo-day per year and one kilo-hour in a century, and a nano 1e-9 is a kilo-kilo-kilo so to less than one sig fig its of the order of a thousandth of an amphour per century. Thermal noise is around a nanovolt per Hz at 50 ohms and room temp (Very roughly) so it would be a trick to use this power level to do much electronically, like generate a measurable radio signal. A much larger battery might be able to power a (edited: continuous) radio beacon.