Free-Methane: Producing Fuel from Waste CO2 Using Renewable Energies

A research aiming at reusing waste CO2 through a prototype methanation reactor (ProGeo) producing carbon–neutral methane by renewable energies was carried out. Preliminary determinations of methane yields by ProGeo have been performed using CO2 either by commercial bottles as well as from grapes fermentation. The obtained results show a complete compatibility with the used commercial catalyser. The ProGeo reactor was designed to produce a CH4 flux of 1 Nm3/h by the Sabatier reaction at a high pressure (2–3 atm) and temperature (200–300 °C). The main goal of our research is to use either low cost or renewable energy to reuse waste CO2 to produce methane in a circular economy scheme. To this end, we have also undertaken the investigation of a new methanation pathway aimed at avoiding the use of the solid catalyst, by exploring mechanisms involving a plasma generation by electrical discharges or by vacuum ultraviolet (VUV) photons on CO2 + H2 gas mixtures. Our research aims to provide a better scientific understanding and a guide to zero-emission technologies to allow industry and regional authorities’ future strategies for energy innovation and sustainable development.