Conventional fuel cells are electrochemical energy conversion devices that produce electricity from an external supply of fuel and an oxidant on the anode and cathode sides respectively. Fuel cells operate continuously as long as the reactants are supplied.

The fuel cell operates by catalytically separating component electrons and protons from the reactant fuel at the anode, and forcing the electrons to travel through a circuit, hence converting them to electrical power.

Electricity can also be produced directly from degradation of organic matter in a microbial fuel cell (MFC). Like any fuel cell, a MFC has an anode chamber and a cathode chamber. The anaerobic anode chamber is most commonly connected internally to the cathode chamber by an ion exchange membrane, and the circuit is completed by an external wire. Microbial fuel cells may use wastewater as a fuel, or more generally a dilute solution of a variety of organic materials in water.

MEGAWATTER^TM process animation

 Microbial Fuel Cell