Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.
Renewable energy production from intermittent sources has seen a large expansion the last decade and has introduced new challenges in the energy system. Problems are related to the non-programmable electric power generated and the production peaks that especially characterize photovoltaic energy. In addition to these issues, the extensive and long-term task of reducing CO2 emissions should be considered. The utilization of CO2 as a feedstock for producing fuels not only contributes to alleviating global climate changes but also provides a new research field for energy development. An innovative process for solar energy storage via methane production seems to be a viable technology to tackle the above-mentioned issues. In this paper an experimental apparatus, formed by PV panels, a pressurized electrolyser and a Sabatier reactor is presented. The Sabatier reaction exothermically combines hydrogen and carbon dioxide to produce methane and water. The produced methane is a carbon neutral gas that fits in with the existing natural gas and allows to overcame issues related to the intermittence and non-programmability of solar power. The paper focuses on the description of the experimental apparatus and the results of a preliminary investigation. An economic evaluation was also carried out on the integration of methanation process with a traditional PV system.