A fuel cell that harvests energy from microbes living in dirt

Many kinds of soil bacteria aren't very picky about their choice of electron acceptor. They're "breathing" using wires instead of oxygen.

> all components...can be purchased at a local hardware store

I can't help but think this would be used for surveillance. All you need is dirt to run a sensor and transmitter. But it's cool science.

It would be interesting to figure out how much does it take away from the soil biome's energy budget. If you did a whole acre of these, would the insects, worms, and millipedes take a hit, and then birds and reptiles etc.?