Techno-Economic Analysis and Optimal Supercritical Carbon Dioxide Power Cycle Configuration for Novel Concentrating Solar Power Plants Adopting Tubular Fluidized Particles Central Receivers

Abstract Concentrating solar power (CSP) plants, thanks to the use of cost-competitive thermal energy storage, can provide back-up power guaranteeing a zero-emission alternative to conventional power plants and offer balancing services to the electrical grid. However, 2023 average CSP levelized cost of electricity (0.117 $/kWh) is still remarkably higher than other renewable technologies. Next-generation solar towers are expected to employ novel receiver technologies to reach temperatures above 700 °C, leading to improved efficiency of the power block and competitive techno-economic performance. In this context, the Horizon Europe POWDER2POWER project aims to demonstrate at MW-scale the operation of innovative tubular receivers adopting fluidized particles reaching temperatures of 750 °C, while ensuring intraweek storage at reduced cost, increasing CSP competitiveness and its value for the grid. For these applications, the adoption of supercritical carbon dioxide (sCO2) power cycles is highly recommended thanks to their high efficiency, compactness of turbomachinery, and simple plant arrangement. This work aims to confirm the potential advantages of sCO2 power blocks for CSP plants based on fluidized particles. A numerical model is developed to calculate the system overall efficiency and the capital cost for different cycle configurations, to identify the optimal techno-economic solution which minimizes the plant specific cost. The model implements ad hoc routines for component sizing and uses referenced cost correlations for power block and solar field components. Results enable to select the optimal sCO2 cycle configuration and design parameters considering the tradeoff between solar-to-electricity efficiency and total investment cost of the plant.