Session: 30-05 Solar Thermal Systems

Paper Number: 122779

122779 - Techno-Economic Analysis and Optimal sCO2 Power Cycle Configuration for Novel CSP Plants Adopting Tubular Fluidized Particles Central Receivers 

Concentrating Solar Power (CSP) plants, thanks to the use of cost-competitive Thermal Energy Storage (TES), can provide back-up power guaranteeing a zero-emission alternative to conventional power plants and offer balancing services to the electrical grid. Current state-of-the-art solar tower plants are based on conventional steam Rankine cycles and adopt solar salts both as heat transfer and storage fluid in a direct 2-tanks TES system. However, as the 2022-average CSP levelized cost of electricity, equal to 0.118 USD/kWh, is still remarkably higher than the one of other renewable technologies, next generation CSP solar towers are expected to employ novel high-temperature receivers able to reach temperatures above 700°C, leading to improved efficiency of the power block and thus to more competitive techno-economic performances. In this context, the Horizon Europe Powder2Power project aims at demonstrating at MW-scale the operation of an innovative tubular solar receiver adopting fluidized particles that will allow to reach temperature as high as 750°C, while ensuring intra-week storage capacities at reduced cost, thereby increasing the flexibility and the competitiveness of CSP generation and its value for the grid. For such a high temperature and high flexibility application, the adoption of sCO₂ Brayton cycles as power conversion systems is the most recommended option thanks to their high efficiency, compactness of turbomachinery, simple plant arrangement, no water consumption and fast transients in operation. This work aims to confirm the potential advantages of this power block technology for next generation CSP plants based on tubular fluidized particles solar receivers and to compare this solution to conventional state-of-art CSP plants adopting steam Rankine cycles. A Matlab+REFPROP V10 numerical model is developed to calculate the system overall efficiency and the capital cost for different cycle configurations, and it is employed to identify the optimal techno-economic solutions which can minimize the specific cost of the overall CSP plant. The model implements ad-hoc routines for the component sizing and uses referenced cost correlations for each component of the power block (compressor, heat rejection unit, recuperators and turbine) and of the solar field (heliostat, tower and receiver). Results will allow selecting the optimal sCO₂ power cycle configuration and nominal design parameters, also considering their impact on the sun-to-electricity efficiency as well as on the total investment cost of the system.

Presenting Author: Dario Alfani Politecnico di Milano

Presenting Author Biography: Dario Alfani is a Research Fellow at the Energy Department of Politecnico di Milano and a lecturer in Renewable Energy for the master's degree program in Energy, Mechanical and Environmental Engineering. He is part of the Group of Energy Conversion Systems (GECOS), where he currently carries out research on power systems employing advanced power cycles as supercritical carbon dioxide (sCO2) and Organic Rankine cycles (ORC) for renewable energy and waste heat recovery applications. His research interests also include novel energy storage solutions based on thermodynamic cycles, as Carnot batteries and Pumped Thermal Energy Storage systems.

Authors:

Dario Alfani Politecnico di Milano
Filip Sobic Politecnico di Milano
Marco Astolfi Politecnico di Milano
Marco Binotti Politecnico di Milano
Paolo Silva Politecnico di Milano