Techno-economic assessment of small-scale solar tower plants with modular billboard receivers and innovative power cycles

This work investigates performances and costs of various configurations of 5 MWel solar tower CSP plants, located in Sicily. The design of the plants aims at comparing two solar towers concepts (i.e., a single tower and modular towers), both adopting billboard receivers. A sensitivity on various heat transfer fluids (i.e., solar salt and sodium), storage fluids (solar salt and NaCl-MgCl2) and power block technologies (i.e., steam Rankine and sCO2 cycles) is also proposed. For each investigated plant configuration, tailored numerical models are presented to assess the performances of each plant subsystem (e.g., solar field, receiver, piping system, power cycle). The results show very competitive LCOE (between 160 and 180 $/MWhel), achievable with satisfactory capacity factors (around 55%), while suggesting good profitability levels for such investments in small scale CSP plants.