The present study explores the integration of supercritical CO₂ (sCO₂) power cycles into Concentrating Solar Power (CSP) plants using molten salt, and the hybridization of these plants with solar photovoltaic (PV) systems through electric heaters. Techno-economic evaluations determined the optimal power cycle configuration and subsystem designs for two different scales and locations and then compared them with state-of-the-art solar power plants. The results show that hybridizing PV with state-of-the-art CSP can lead up to a 22% reduction in the Levelized Cost of Electricity (LCOE) compared to standalone CSP systems. This hybridization and the use of electric heaters are particularly beneficial for small-scale installations and locations with low DNI/GHI ratios. By replacing the steam Rankine cycle with a sCO₂ power block, a further 42% reduction in LCOE can be achieved at small scales, even with a simple recuperated cycle. In conclusion, the hybridization with PV and the integration of sCO₂ power blocks provide cost benefits despite the temperature limitations imposed by the molten salt. Hybrid PV-CSP plants with sCO₂ power blocks prove to be a cost-effective solution for capacity factors exceeding 60%. For lower capacity factors, configurations combining PV with battery energy storage or PV with electric heaters, thermal energy storage, and sCO₂ power blocks are preferable options.

To enable the widespread exploitation of intermittent, low-cost, and non-dispatchable renewable energy technologies, energy storage plays a key role in providing the required flexibility. This study introduces maps of optimal combination of Thermal Energy Storage (TES) and power cycles, supporting decision-making in power-to-heat-to-power applications. These maps span a wide temperature range from 200 to 1200 °C and are proposed for different charging costs, installed capacities, and storage durations. For thermal-to-electricity reconversion, this study explores power blocks including steam Rankine cycle, supercritical CO₂ (sCO₂) Brayton cycle, Organic Rankine Cycle (ORC), and combined gas turbine with Rankine and sCO2. Results highlight that, in a grid-based plant with a 50 EUR/MWh charging cost, the most cost-effective pairing involves sCO2 cycles with recompression and intercooling, with particle TES at 600–800 °C. Air packed-bed suits scenarios where TES contributes significantly to capital costs or involves low charging costs. Molten salt TES is the optimal choice when the design temperatures align with salt temperature limitations. Particle TES proves cost-effective across a broad temperature range and scales (10–200 MW). For solar-based systems, the integration of molten salt TES with simple sCO2 recuperated cycles demonstrates market potential for southern European locations.

This study evaluates the techno-economic performance of hybrid PV–CSP power plants using high-temperature particle receivers and compares them directly with molten-salt-based alternatives, with all systems integrated into supercritical sCO2 (sCO2) Brayton power blocks. A unified simulation and optimization framework is applied to quantify the cost and performance potential of particle-based CSP when combined with PV and long-duration thermal storage. For a representative 10 MWe plant located in Évora (Portugal), particle hybrid PV–CSP– sCO2 systems achieve minimum LCOE of 72 EUR/MWh at capacity factors near 80%, demonstrating that particle-based system can enable competitive firm renewable electricity at small scale. Results show that sCO2 cycle layouts including intercooling only can match the techno-economic performance of more advanced configurations because their lower specific investment outweighs differences in thermal efficiency. Parallel electric-heater integration allows flexible TES charging and consistently outperforms EH in series arrangements, which require oversized PV capacities. Sensitivity analyses quantify main impact on the LCOE, driven by solar-field and power-block costs, whereas TES cost plays a secondary role. When the system is in a high-DNI location such as Likana (Chile), the minimum LCOE decreases by 20% and achievable capacity factors exceed 90%, with CSP becoming the dominant generation part and eliminating the need for electric heating. System-level benchmarking against PV–BESS, molten-salt tower and trough CSP, and PV-based electric-heater systems shows that particle hybrid PV–CSP– sCO2 plants consistently deliver the lowest LCOE at capacity factors above 60% at competitive cost.

To enhance the economic viability of Concentrating solar power (CSP) plant, recent efforts have been directed towards employing high-temperature working fluid in the receiver and incorporating higher-efficiency power cycles. This work presents a techno-economic analysis of a sodium-chloride salt heat exchanger included in a sodium-driven CSP system with a supercritical CO2 power block. A quasi-steady state heat exchanger model was developed based on the TEMA guidelines, with the possibility of being customised in terms of media adopted, constraints, boundary conditions, and heat transfer correlations. The sodium-salt heat exchanger has been designed aiming at minimising the Levelized Cost of Electricity (LCOE) of the plant. The performance and the design of the proposed heat exchanger have been evaluated via multi-objective optimisation and sensitivity analyses. Results show that advanced CSP systems employing sodium and an indirect chloride salt storage can represent an economically viable solution and can drive towards the future goal of 5 USD/MWh. For a base-case 100 MWe plant with 12 h of storage, a LCOE of 72.7 USD/MWh and a capacity factor (CF) higher than 60% were reached. The techno-economic investigations showed the potential LCOE reduction of 6% as well as the flexibility and robustness of the heat exchanger model. The developed tool lays the groundwork to explore potential improvements of this new generation of CSP systems.

The integration of compact and high-efficient supercritical CO2 (sCO2) power blocks has been identified as one of the key alternatives for enhancing the economic viability, and the flexibility of Concentrating Solar Power (CSP) plants. The present work aims at identifying and selecting the most promising CSP plant configurations that can be integrated with sCO2 power blocks. Several sCO2 – CSP layouts are identified, classified by the receiver heat transfer fluid and storage design, and benchmarked through a methodology developed by the authors. An analytical approach, based on purposely defined techno-economic criteria, is defined to benchmark each layout with an overall score. The following criteria are considered: maturity, low-cost potential, maximum temperature, safety, and system complexity. The overall score is then derived by combining the mentioned criteria and weighting factors. A comparative analysis is proposed, in which the higher the resulting overall score, the more attractive the layout was deemed. The CSP layout employing molten salts results in being the most attractive one, standing out for its maturity. The air- or particle-based configurations combined with packed beds or particle silos as storage are promising for their low-cost potential and high operating temperatures.

Techno-economic performance simulations play a crucial role in assessing the feasibility, cost-effectiveness, and overall impact emerging renewable energy system designs. Concentrating Solar Power (CSP) is a promising technology for decarbonizing the electricity grid by integrating cost-effective thermal energy storage (TES). However, their development is hindered by their high levelized cost of electricity compared to other energy sources. Hybrid systems that connect with solar photovoltaic (PV) and battery systems are a viable solution to reduce the cost of these plants while maintaining flexibility and guaranteeing firm production despite the intermittence of solar availability. This paper presents MoSES (Modeling of Solar Energy Systems), an open-source techno-economic modeling tool designed to evaluate the feasibility and cost-effectiveness of hybrid PV-CSP plants. While existing simulation tools perform well with established systems, they face challenges when adapting to new components, configurations, and operating strategies. MoSES addresses this challenge by providing a simulation framework and a versatile library of components and control strategies that can be modified to meet end-users’ needs. The tool enables simulation activities to assess the advantages, optimize the design, and benchmark different hybrid PV-CSP plant layouts. This paper outlines the methodology employed to determine system design, costs, and key performance indicators, as well as to estimate operational performance. Furthermore, a case study is presented to illustrate MoSES's effectiveness as a tool for conducting annual simulations despite being in its early stages of development. MoSES provides a valuable contribution to the solar community by enabling the evaluation of the impact of emerging solar-based system designs.