# A Novel Hybrid CSP-PV Power Plant Based on Brayton Supercritical CO\({}_{2}\) Thermal Machines
## 1 Introduction
This was achieved while maintaining a high capacity factor and reducing the LCOE in the range of 4% to 7% for plants with parabolic trough collector (PTC) technology and between 1.5% and 4% for plants with central receiver system (CRS) technology. In addition, a reduction in solar field size of approximately 40% was observed for PTC hybrid plants and 30% for CRS hybrid plants. In a similar analysis, in South Africa [7], capacity factors of up  
Figure 1: Conventional scheme of hybrid CSP-PV plants. to 90% were obtained, with an LCOE of USD 133-157/MWh. In [8], typical capacity factors for intermittent renewable energy sources were revealed to be in the 20% to 40% range. However, the Solar Reserve's Crescent Dunes project achieved a capacity factor of over 80%, and when combined with PV systems, the capacity factor rose to approximately 90%. In [9], a methodology for designing and sizing hybrid CSP-PV plants was described, which used a transient simulation model coupled with an evolutionary optimization algorithm. The results showed that the capacity factor reached values above 85% and the LCOE was lower than stand-alone CSP plants. In [10], a case study that calculated the LCOE for a hybrid CSP-PV plant at the Atacama Solar Platform was presented. The objective was to evaluate new options for continuous power delivery. The results indicated that CSP-PV plants are a feasible option that can contribute to the continuous delivery of sustainable electricity. Two LCOE scenarios, based on IEA studies, were evaluated between 2014 and 2050, obtaining values of USD 146.9 and 85.7/MWh and USD 138.8 and 77.4/MWh, respectively. The integration of CSP-PV plants in two Saudi Arabian cities, Riyadh and Tabuk, was analyzed in [11]. By setting a capacity factor of 79%, it was found that a solar multiple of 6 in Riyadh and 3.5 in Tabuk was required for a single solar plant. However, with the introduction of the hybrid concept, the solar multiple was significantly reduced. It ranged from 2.9 to 3 in Riyadh and from 1.78 to 1.85 in Tabuk. A review of advanced power cycles to improve efficiency and reduce costs was carried out in [12]. It was mentioned that subcritical steam turbines are a developed option, but more agility and flexibility in their operation are required. On the contrary, supercritical steam turbines are considered interesting but are generally too large for existing solar towers. Closed Brayton cycle systems with supercritical CO2 (S-CO2) are in the early stages of development but offer the promise of high efficiency at reasonable temperatures and in various capacities, with the prospect of significantly reduced costs. In [13], different supercritical CO2 power cycle configurations in a hybrid CSP-PV plant with salt storage were analyzed. The scalability of the plant was investigated, obtaining an LCOE below EUR 66/MWh and capacity factors above 70% for a capacity of 100 MWe. In locations with high solar irradiation, a capacity factor of 85% and an LCOE of EUR 46/MWh was achieved. In addition, no significant differences in terms of the S-CO2 power cycle configuration were observed. A hybrid CSP-PV-wind plant based on the S-CO2 Brayton cycle was proposed for different load demand scenarios [14]. It was proven that the load demand scenarios significantly impact load matching and economic performance. The system can meet more than 90% of the annual load demand. The LCOE reached USD 216.9/MWh for the load following scenario, being 32.1% higher than in stable production scenarios. Hybridization of CSP and PV systems can include thermal energy storage and battery energy storage systems (BESS) to offer cost-competitive renewable energy and load capacity. It was found that a CSP-PV plant with TES and BESS increased the capacity factor, reaching values above 85% [15]. However, a significant reduction in battery bank cost (on the order of 60-90%) was required to achieve significant savings. In current scenarios, a CSP-PV plant with TES presents better economics and reliability compared with a system with BESS [16].