Microbial fuel cells are a unique, and highly speculative, approach to generating renewable energy by feeding organic waste to microbes that subsequently generate electricity. The process is built on principles that have been known for many years, though getting microbes to part with stray electrons has always involved bathing them in harsh solvents.
Microbial fuel cell technology is an effort to reduce or eliminate the negative waste products of this process while boosting the amount of electricity the microorganisms are able to produce. The process entails placing microbes of species such as Shewanella putrefacians in an oxygen-free anode chamber built into the fuel cell. In their oxygen-deprived state, the microbes begin metabolizing the organic waste around them to produce the energy necessary to sustain life.
Since the bacteria are in an oxygen-free environment, the surplus of electrons they produce as a byproduct of this metabolic process do not bond with oxygen. Instead, these electrons form a thin current that flows through the anode point upon which the microbes reside. As of 2014, the technology does not work on a commercially viable scale, though early research shows that the underlying process is sound. It is possible that the charge these microbial colonies are capable of producing is just not strong enough to provide much power.