The value of thermochemical storage for concentrated solar power plants: Economic and technical conditions of power plants profitability on spot markets

This paper explores two new paradigms by studying the techno-economic relevance of a concentrated solar power plant in spot electricity markets involving strong price variations, and by investigating the integration of an innovative thermal storage performed by a thermochemical process in such plant. Its aim is to optimize simultaneously the physical characteristics of the storage and the operation of the plant (combining production/storage/discharge phases). The methodology is based on pre-scenarios for the plant operation, and net present value as optimization criteria. The results show original scenarios involving one or two discharge phases (according to day, season, solar multiple, or location) with higher revenues and stored energies than the classical scenario (i.e. one discharge at sunset). Nevertheless, these revenues in the spot market are too low, leading to negative net present values. Thus, such power plant requires subsidies, that are here estimated from 12 (sic)/MWhe (depending on case study), which are much lower than classical flat feed-in tariffs.