Techno-economic analysis of multi-tower solar particle power plants

Solar tower systems using solid particles as heat transfer and storage medium promise to achieve, in combination with advanced power cycles, lower levelized cost of electricity (LCOE) than state-of-the-art concepts. In this study the cost potential of a multi-tower solar power plant with centrifugal particle receiver is evaluated. Most of the underlying assumptions were chosen in accordance with those specified within the US-DoE Gen3 project "G3P3". For the power block a high-efficiency supercritical CO2 system with 100 MWe was assumed. The solar subsystem is built from 12 identical solar tower modules, each with heliostat field, tower, receiver and storage.The nominal thermal power of each module is 41 MWth. Since the cost assumptions for the tower and the heat exchanger (HX) are still relatively uncertain, different correlations were used representing optimistic and conservative cases. For the particle receiver two outlet temperature levels were investigated, namely 800 degrees C and 1000 degrees C. The results of the techno-economic analysis indicate a strong impact of the cost assumptions for the primary heat exchanger and the tower. With 800 degrees C as particle outlet temperature, the estimated LCOE range from $56.18/MWh (optimistic values for tower and HX cost) to $67.30/MWh (conservative values for tower and HX cost).Increasing the particle outlet temperature to 1000 degrees C results in a significant reduction of LCOE (about 12% for the optimistic cases, down to $50.46/MWh). The reason for this is the significant reduction of heat exchanger area, particle inventory and particle mass flow, resulting from the larger temperature difference in the particle system. However, operating the system at such elevated particle temperatures will require some modifications to the components that are not fully reflected in the used cost correlations yet. Nevertheless, the results propose further investigation of this option. All in all the results indicate a clear potential to achieve the SunShot goal of less than $60 /MWh.