Optimization of thermal energy storage integration strategies for peak power production by concentrating solar power plants

The integration of thermal energy storage systems in concentrating solar thermal power plants allows power production to be shifted from times where there is low demand to periods where electricity prices are higher. Although increasing the total investment, thermal energy storage can therefore enhance profitability of the solar power plant. The present study presents optimum power plant configurations for a given location considering different price-based grid integration strategies. Such optimum plant configurations were determined using a thermo-economic optimization approach to compare the profitability of generating electricity assuming an instant-dispatch strategy with respect to a selective operating strategy where electricity is produced only during peak price hours of the day. For each of these price-operating strategies, optimum plant configurations were found by varying two solar-related design parameters, namely the solar multiple and the storage size, whilst simultaneously evaluating the economic performance of each design. Results show that for the case of smaller storage units and solar field size a peaking approach will yield more revenues at the end of the project, thus highlighting the importance of the availability of reliable predictable demand and meteorological data for the plant operators. Moreover, results confirm that for the location considered, the best plant configurations encompass large storage units and solar field sizes, for which the gain of a peaking operation strategy becomes negligible since the plants start behaving similar to a baseload power generation station. Finally, it is performed a sensitivity analysis with respect to the available price data and the influence of renewable electricity incentives, particularly the investment tax credit treasury cash grant, showing the positive impact that such measurements could have in augmenting the economic viability of concentrating solar power and thus serve as a driving force for technology deployment. (C) 2013 The Authors. Published by Elsevier Ltd.