Let's see They claim 10uW at 3 meters. A random Lithium Thionyl Chloride battery (http://www.xenoenergy.com/eng/file/Xeno%20Catalog%20XL-050F_E.pdf http://www

Let's see They claim 10uW at 3 meters. A random Lithium Thionyl Chloride battery (http://www.xenoenergy.com/eng/file/Xeno%20Catalog%20XL-050F_E.pdf http://www.xenoenergy.com/eng/file/Xeno%20Catalog%20XL-050F_...) for about 2$ can deliver 35uW for 10 years in a ridiculously small package. This well outlasts the lifetime/usefulness of anything which could be potentially connected to it. And even if not, changing a battery every 10 years is not exactly a huge problem. (Disclaimer: I have only skimmed the paper very quickly)