While the levelized cost of energy (LCOE) is generally emphasized when assessing the economic viability of renewable energy systems, the other benefits such as the operational and capacity value are often ignored. Concentrating solar power with thermal energy storage (CSP-TES) can be dispatched similarly to conventional thermal generation, which may lead to incorrect economic comparisons between CSP-TES and variable renewable generation technologies such as wind and photovoltaics (PV). However, unlike most conventional thermal power plants, CSP-TES plants are energy limited, meaning that their response might be restricted by solar availability. Therefore, the use of this limited solar energy must be optimally scheduled to provide the greatest value to the power system. The timing of CSP-TES dispatch depends on a variety of factors, including electricity demand patterns, the penetration of variable generation sources, and the configuration of the CSP-TES plant itself. We use an established CSP-TES modeling framework in a commercially available production cost model to study the dispatch and value of a molten salt tower CSP-TES plant in a test system simulating the Colorado grid. We examine a range of configuration parameters by varying the relative sizes of three separate but interrelated parts of the CSP-TES plant: the solar collection field, the power block, and the thermal storage tank. Firstly, we observe that increasing the thermal energy storage capacity of a plant reduces spilled energy and increases the ability to deploy thermal energy to displace the most costly forms of conventional generation. Additional storage, however, shows only marginal benefit beyond 6–9 hours of rated plant capacity. Secondly, we observe that reducing the ratio of solar collection field size to power block capacity (a design parameter often called the solar multiple [SM]) provides the most benefit to this test system per unit of energy produced. A large solar collection field size, relative to the rated capacity of the power block, forces some solar energy to be stored during the periods when conventional generation is most costly. The stored solar energy must then be used during off-peak hours to displace less costly fossil generation. The relative value of CSP-TES presented here is dependent on many system variables, including existing solar energy penetration. Future work must examine the impact of capital cost on the overall value proposition of these configurations of CSP-TES, since the upfront cost is not considered here.

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