Techno-economic analysis of a hybrid PV-CSP system with thermal energy storage applied to isolated microgrids

In this work an economic and technical analysis on a hybrid Photovoltaic (PV) - Concentrated solar power (CSP) system, to be used as an energy source in isolated microgrids, is conducted using the microgrid in Puertecitos, Baja California, Mexico as a case study. The PV-CSP system uses a field of solar concentrators with thermal storage to activate a 30 kW organic Rankine cycle, which satisfies the community's energy demand during periods of low or no solar radiation. The PV field provides 73 kW to cover the electrical needs of the community during the daytime, the period in which the CSP field stores sensible heat in tanks for later use. An operational and economic study that compares the hybrid system to the one currently used in the microgrid is presented. The results show that, for the case study, the levelized cost of energy (LCOE) for the PV-CSP hybrid system is 0.524 USD/kWh, only 2% higher than the LCOE for the PV-Battery, 0.51 USD/kWh. However, if the PV-CSP were used in a community with an energy demand 50% larger, the LCOE would be of 0.506 USD/kWh. Furthermore, if the community's demand exceeds 500 kW, the LCOE of the PV-CSP would be 26% lower. If the system is harnessed to its maximum capacity throughout the year, its LCOE can be comparable to, and as competitive as that of large commercial hybrid plants. The hybridization of these systems allows a manageability and complementarity of energy that, when applied to isolated microgrids, diminishes or eliminates the problem of battery storage, resulting in costs reduction during the useful life of the project.