The effect of real-time external resistance optimization on microbial fuel cell performance

This work evaluates the impact of the external resistance (electrical load) on the long-term performance of a microbial fuel cell (MFC) and demonstrates the real-time optimization of the external resistance. For this purpose, acetate-fed MFCs were operated at external resistances, which were above, below, or equal to the internal resistance of a corresponding MFC. A perturbation/observation algorithm was used for the real-time optimal selection of the external resistance. MFC operation at the optimal external resistance resulted in increased power output, improved Coulombic efficiency, and low methane production. Furthermore, the efficiency of the perturbation/observation algorithm for maximizing long-term MFC performance was confirmed by operating an MFC fed with synthetic wastewater for over 40 days. In this test an average Coulombic efficiency of 29% was achieved.

Research highlights
► A simple perturbation/observation algorithm is used to maximize MFC power output by matching internal and external resistances in real-time.
► Real-time optimization of electric load (external resistance) resulted in increased power output, improved Coulombic efficiency, and low methane production.
► The efficiency of the real-time algorithm was confirmed by operating an MFC fed with synthetic wastewater for over 40 days.