Turns out soil has electric voltage in it. Earth battery's are nothing new they have been in use since telegraphs were a thing. In 1886 Nathan Stubblefield filed a patent for a battery "In 1898, Stubblefield was issued U.S. Patent 600,457 for an "electric battery", which was an electrolytic coil of iron and insulated copper wire that was immersed in liquid or buried in the ground. Stubblefield made the unsubstantiated claim that, combined with normal battery operation, his device also drew additional power from the earth. However, it did successfully serve as both a power source and ground terminal for wireless telephony." https://en.wikipedia.org/wiki/Nathan_Stubblefield#Inventions Someone mentioned in the comments of an instructibles guide "Ew17 Reply2016-08-09 I have made this countless times, its fun! I use an aluminum soda can that doubles as the container and ground connector. The copper in the wire itself acts as my positive connector. Me and my friends plan to use em to light a fort we built in the woods." http://www.instructables.com/id/An-Easy-Cheap-Soil-based-Microbial-Fuel-Cell/ It works is a proven technology, could be added to game to power low voltage devices such as some lighting, power a radio recharge small devices. IRL its something im exploring different designs and potential with like electromagnetism i fiind it fascinating.