NEWCLINE. Advanced thermocline concepts for thermal energy storage for concentrated solar power (CSP). Final report

The Newcline project aimed to develop a cost-effective thermal energy storage solution for Concentrating Solar Power (CSP) plants by replacing traditional two-tank molten salt storage with a single thermocline tank containing a structured ceramic filler material. This innovative design sought to reduce capital (CAPEX) and operational (OPEX) costs by minimizing the amount of molten salt required. Initial estimates suggested potential savings of up to 40% for the storage subsystem, translating to 5%-10% in overall CSP plant CAPEX, depending on the plant type—Central Receiver (CR) or Parabolic Trough Collector (PTC), the two CSP type plants considered in the frame work of the project. The project, carried out by five international partners, focused on various aspects including material development, heat transfer analysis, and dynamic simulations of the CSP system integrating the novel storage using SPF-OST's pytrnsys simulation framework. The simulations compared the thermocline storage system's performance against the conventional two-tank storage system, and parametric studies were conducted to optimize its operation. Results indicated that thermocline CSP systems generated slightly less electricity—between 70% and 100% of the electricity output of conventional two-tank storage CSP systems. Economic analyses were conducted to evaluate the Levelized Cost of Energy (LCOE) for the systems. While PTC plants showed potential for up to 6% lower LCOE, CR plants did not demonstrate economic advantages. The project suggests thermocline systems are more suited for applications where molten salt costs are a significant investment, including smaller-scale industrial processes beyond CSP plants.