Integration of concentrating PVs in anaerobic digestion for biomethane production

Biogas produced from anaerobic digestion processes is considered as an important alternative to natural gas and plays a key role in the emerging market for renewable energy. Aiming at achieving a more sustainable and efficient biomethane production, this work proposed a novel energy system, which integrates concentrating photovoltaic/thermal (C-PV/T) hybrid modules into a biogas plant with chemical absorption for biogas upgrading. The investigated energy system was optimized based on the data from an existing biogas plant, and its techno-economic feasibility was evaluated. Results show that about 7% of the heat consumption and 12% of the electricity consumption of the biogas plant can be covered by solar energy, by using the produced heat in a cascade way according to the operating temperature of different processes. The production of biomethane can also be improved by 25,800 N m(3)/yr (or 1.7%). The net present value of the integrated system is about 2.78 MSEK and the payback period is around 10 years. In order to further improve the economic performance, it is of great importance to lower the capital cost of the C-PV/T module.