In recent decades, interest in microbial electrochemical technologies (MET) has drastically grown. MET rely on the ability of some microorganisms to form electroactive biofilms and to catalyze oxidation reactions at the anode and / or reduction reactions at the cathode. These technologies have aroused interest for their incredible versatility and sustainability as they can convert organic matter contained in wastewater and CO2 (inorganic source) contained in gas waste into H2 and high-value chemicals such as biofuels. Depending on their configuration, MET can also be applied for nutrient recovery, microbial electrochemical remediation, seawater desalinization and production of bioenergy. Despite the enormous variety of case studies reported in literature, MET nowadays still suffer from an issue related to scale up due to low power output if compared with modern renewable energy sources such as solar, wind, hydropower, fuel cells and lower removal yields than wastewater treatment systems such as anaerobic digesters (AD).