Solar fuels based on the integration of food wastes and photovoltaic through energy storage

Energy recovery from meat industry waste through the integration of solar energy could be the cornerstone of solving a serious global problem. In this regard, it is crucial to address the limitations of this waste and the challenges of transforming it into solarfuel. This manuscript presents different integrations based on commercial technologies, focusing on the integration of solar energy in a low-temperature digester for the dehydration and separation of fatty acids. In this regard, different systems are proposed depending on the level of solar energy integration, from the most basic system using photovoltaic electric heating to a 100% renewable system that integrates thermochemical storage based on calcium looping and biofuel feedback. The analysis of the systems has been carried out from an energy and economic perspective based on real data of waste and irradiation over an annual cycle, providing valuable information for future research on the dynamic behavior of the systems. The study demonstrates that the system integrating energy storage and biofuel feedback could generate 100% renewable fuel, achieving NER values between 4.5 and 8 depending on the waste managed, and a solar-to-fuel performance of up to 44%, exceeding current levels. The integration of well-established technologies also leads to competitive economic values, achieving LCOE values of up to €62/MWh, demonstrating independence from the fuel market. In addition, combustion tests have been carried out that support the integration of the generated solarfuel for industrial heat generation with minor modifications, leading to promising results in terms of efficiency and sustainability.