Electrochemical Impedance Spectroscopy is employed to understand the role of anodic capacitance and individual component resistance in the bioelectricity generation of microbial fuel cells.The anodic capacitance during initial bacterial growth and biofilm formation (1–9 days) is 6 times higher than the literature data.The power density calculated on day 24 being 0.497 W/m 2 which is approximately 3 times higher than the literature data.The maximum columbic efficiency obtained is 30.8% which is 2.8 times higher than literature. These results demonstrate that the mixed culture bacteria is more efficient in bioelectricity generation in microbial fuel cells and the anodic capacitance due to biofilm growth on anode plays an important role in the power generation of microbial fuel cells. The electrode resistance dominates over solution resistance due to Hydrogen Evolution and Oxygen Reduction Reactions. © 2018 Hydrogen Energy Publications LLC