The bioelectroconversion of renewable feedstocks, such as wastewater, and CO2 into sustainable fuels is an attractive alternative for the achievement of a future decarbonized and circular economy. While adopting a power-to-gas/fuel approach, these bioconversion processes also represent a suitable option to balance the electrical grid, in the scenario of high penetration of renewable energy sources, which is likely to happen in the forthcoming years. GAIA aims developing novel, energy-efficient solutions for obtaining both liquid (butanol) and gas (methane) biofuels, based on microbial electrochemical technologies (MET). MET use electroactive microorganisms to catalyse the electrochemical process of CO2 conversion to fuels, they operate under mild conditions and without need of externally produced H2, thereby decreasing the energy requirement of the process. METs are highly flexible to diverse CO2-exhaust gases, wastewaters and RES surplus scenarios. GAIA will increase the electrical current density of METs, boosting the production rate to >1 m3/m3/d for methane and > 0.25 kg/m3/d for butanol. Both will allow to increase the economical competitiveness of the MET technology, decreasing more than order of magnitude its current fuel production costs. GAIA will achieve these goals through improvement of electrode materials and reactor geometries by additive manufacturing, enhancement of electrodemicroorganism interaction and bioprocess engineering approaches. The technology will be validated at laboratory-scale (TRL4) and a complete techno-economical, replicability and societal assessment will pave the ground for benchmarking and commercialization of the technology in the future. Thanks to a societal assessment, stakeholders´ needs and concerns will be addressed to promote public acceptance and awareness, increasing societal readiness of the proposed solution. In terms of exploitation, the use of CO2 and renewable feedstocks to produce sustainable fuels, will help to create novel business models for wastewater treatment plants (among other potential stakeholders), which will turn into biorefineries, based on Circular Economy principles, while promoting their decarbonization. Project outputs, together with an exploitation plan, will set the roadmap for short/medium term market implementation of the technology. GAIA multidisciplinary consortium has all the necessary expertise to guarantee the project successful implementation.