Energy and Cost Analysis of Concentrated Solar Thermal Plants Integrated With Latent Heat Thermal Energy Storage for the Decarbonization of Industrial Processes

Industrial energy demand in the EU is driven by the thermal energy share, which accounts for the most part of the total energy demand. A large part, about one-third, is at medium temperatures, between 100 and 200 °C, and it is still produced by fossil fuels, mainly natural gas. This energy demand could be met by solar thermal energy by using Concentrated Solar Thermal (CST) technologies, suitably combined with thermal energy storage systems. This paper presents a study of CST plant composed by Parabolic Trough Collectors (PTC) combined with Latent Heat Thermal Energy Storage (LHTES) system in shell-and-tubes configuration for the supply of heat for industrial processes. Firstly, the criteria adopted for the sizing and the quasi-static simulation of the system are described. Significant attention is given to evaluate the variation of the Solar Fraction (SF) with the typical parameters of thermal storage, such as the maximum capacity and exchange surface, given a specific location and the Solar Multiple (SM). The methodology has been applied to a dairy processing facility within the agri-food sector with a thermal load of 500 kWth. Then, an economic analysis has been carried out by evaluating the impact of the component’s costs, such as the linear parabolic collectors, thermal storage materials and landscape preparation. Finally, the Levelized Cost of Heat (LCOH) has been computed for different thermal storage sizes in order to find the best combination that minimizes it. As a result, despite the overall increase of the SF with the thermal storage capacity, the proposed work shows how the minimum value of the LCOH (7.24 c€/kWh) corresponds to low storage capacity (1 MWh).