Optimal integration of the year-round operation for methane production from CO2 and water using wind, solar and biomass

Abstract In this paper we integrate the use of biomass, wind and solar energy for the constant production of synthetic methane over a year to determine the optimal combination of renewable energy to maintain a production level and to store it in a ready to use and practical form. Biomass is used for the production of power and/or hydrogen. Photovoltaic solar and wind energy are used to obtain power. The power is used to split water through electrolysis to generate oxygen, which is used to process the biomass and hydrogen, that is used to synthesize methane together with CO 2 . The optimal operation of the facility involves the use of biomass for the production of power, while hydrogen is to be produced from water electrolysis. The investment and production costs are 175 M€ and 0.38€/Nm 3 respectively. A sensitive analysis shows that biomass is used when its price is lower than 50€/t and for investment rates below 1500€/kW. Solar energy is used for power when the price of biomass is high and only if the solar incidence is above 1200 kWh/m 2 yr. The use of wind is recommended where there is a low solar incidence and wind velocities above 9 m/s.