A Cost and Performance Evaluation of SUNDISC: A Dual-pressure Air Receiver Cycle

Abstract

Abstract A dual-pressure air receiver cycle has previously been proposed to overcome limitations of combined cycle CSP plants. The economic and energetic performances of this so-called SUNDISC cycle are investigated in the present work. To do so, an annual hourly thermodynamic model is used with varying configurations of solar field size, steam turbine rating, storage capacity, low-pressure receiver system and hybridization modes. The conducted simulations show the lowest levelized cost of electricity for small solar components and considerable fuel co-firing rates at 0.08 USD/kWhe. However, the results were produced with exceptionally low fuel cost and, furthermore, solar power plants are expected to be limited to low fuel usage. When the co-firing rate is capped at 20% and 5%, the minimum achievable costs increase to 0.10 USD/kWhe and 0.12 USD/kWhe, respectively. These latter results are generated with high steam turbine ratings as well as large low-pressure receiver systems, solar fields and thermal energy storage systems. The resulting annual time of no power generation, as a measurement of the plant's baseload capacity, was less than 800 h. If longer plant operation is aspired either cost or fuel co-firing rate increase. The rock bed thermal energy storage system is found to add only minor costs to the plant. Large storage capacities are, therefore, viable and the technology plays a vital role in enabling baseload electricity generation from solar energy. Refinements are recommended for the component cost model and plant operation control. The latter should be made more flexible to find optimized hybridization modes.