The SolarPACES Conference Proceedings cover the proceedings of the international SolarPACES conferences taking place annually.
TIB Open Publishing (Technische Informationsbibliothek (TIB))
Selection of Glass Alternative Materials for Manufacturing Heliostat Reflective Facets
Traditional concentrating solar power plants utilize silvered glass reflective facets that account for a significant portion of the total plant cost. Several cost-effective non-glass reflectors have been developed. A majority of these novel reflectors are flexible, which necessitates exploring support structures to maintain their shape during use. This study presents a methodology for evaluating and selecting structural support materials for non-glass heliostat facets. The approach employs analytical models to efficiently screen a large pool of candidate materials based on strength, stiffness, and deflection due to gravity, using an existing glass reflector panel as a reference. During analysis, sandwich panels showed promise as viable support for the reflector. The most promising sandwich panel designs are further investigated using experimental testing. The analytical model predictions are found to align moderately well with physical test results, validating its utility for rapid material selection. The top-performing sandwich panel designs demonstrate the potential for cost savings and increased facet size compared to traditional glass facets. This research provides a framework for evaluating and selecting structural materials for non-glass heliostat facets, enabling improved cost-effectiveness and performance of concentrating solar power systems.
Copyright (c) 2025 Jean Schnaar-Campbell, Craig McGregor, Johann Bredell https://creativecommons.org/licenses/by/4.0
From Global to Local: Learning from Worldwide CSP Successes to Drive Chile’s Solar Power Industry Forward
Concentrated Solar Power (CSP) technology offers a promising solution for enhancing the stability and reliability of renewable energy systems, particularly in regions with high solar resource availability like Chile. However, CSP deployment faces significant challenges, including technological mistrust, high costs, and regulatory barriers that hinder its growth. This study provides an in-depth analysis of global CSP successes and identifies key strategies and challenges relevant to Chile's context through a mixed-methods approach, including a comprehensive literature review and stakeholder interviews with key players in the Chilean CSP industry. The results reveal significant technological, regulatory, and financial barriers to CSP deployment, including issues with thermal energy storage (TES) systems, specifically the failures of molten salt tanks. Despite recent declines in CSP capital expenditures and the potential for further cost reductions, the study highlights the critical need for regulatory reforms and tailored policy support to address current market and technological limitations. Key recommendations include enhancing R&D investments to improve TES reliability, streamlining permitting processes, and fostering public-private partnerships to unlock CSP's full potential. The findings underscore the necessity of strategic incentives and business model innovations to enable the commercial-scale deployment of CSP in Chile, ultimately supporting the country's decarbonization goals and strengthening energy security.
Copyright (c) 2025 Carlos Felbol, Francisco Moraga, María Teresa Cerda, Frank Dinter https://creativecommons.org/licenses/by/4.0
Designing an Integrated CSP-SOE System for Hydrogen Production
This paper presents the design, and simulation of a novel concentrated solar power (CSP) system integration with solid oxide electrolysis (SOE) to generate superheated steam required for efficient hydrogen production. The system comprises of 10 parabolic dish collectors, SiSiC cavity receivers, and a heat exchanger with two components. An evaporator and a superheater collectively achieve a high thermal efficiency of 73%. Computational fluid dynamics (CFD) simulations demonstrated that the SiSiC receiver can maintain an air outlet temperature of 1555K, which is 8% more efficient than a similar design reported in the literature. This would facilitate the generation of superheated steam necessary for the SOE process. A water flow rate of 28.8kg/h directly influences the system's hydrogen production capacity, which reaches 2.56kg/h at optimal conditions. The heat exchanger components were designed using Aspen EDR, while the entire system simulation was conducted using Aspen Plus, demonstrating the system's potential to meet industrial standards for sustainable hydrogen production. This article serves as a good reference in investigating the feasibility of CSP-SOE systems as a promising pathway for large-scale renewable hydrogen production.
Copyright (c) 2025 Abdullah Ayed Alrwili, Khalifa Aliyu Ibrahim, Peter King, Ahmed Ali Aldubayyan, Yousef Lafi A Alshammari, Zhenhua Luo https://creativecommons.org/licenses/by/4.0
Materials Comparison for Reducing Heliostats Production Costs
The alarming issue of climate change and the necessity to increase the renewable energy stake has become the driving force for cost reduction measures taken in various renewable technologies. Concentrated Solar Power (CSP) is an increasingly attractive solar energy technology that uses heliostats to provide controllable, rapid heating and thermal energy storage (TES) benefits, which can use high temperature fluids (HTF) for higher efficiencies. The cost of installation for a commercial heliostat assuming a production volume of 22,239 heliostats, which represents a solar field aperture area of 1,078,592 m2, is $127/m2, or 136.98 million for the solar field [1]. Around 31% of the cost comes from manufactured parts which include the heavy use of steel, which can be subject to high price volatility, to ensure structural stability under wind load conditions. By studying the structural vibration response for different types of composite materials, a case can be made to switch from the heavy use of galvanized steel to a hybrid or even complete use of composite materials for heliostat construction. This paper presents a structural vibration response comparison between Steel AISI 1020, Glass Fiber Reinforced Polymer (S-Glass and E-Glass), Basalt Fiber Reinforced Polymer, and Carbon Fiber Reinforced Polymer (230, 290, and 395 GPa.) for heliostats structure manufacturing.
Copyright (c) 2025 Javier Martell, Kenneth Armijo, Dimitri Madden https://creativecommons.org/licenses/by/4.0
Demonstration of a Proof-of-Concept Integrated Skip Hoist-Thermal Energy Storage System
This paper presents the design, construction, and preliminary testing of an innovative skip-hoist particle lift (PL) integrated with a multi-layered cylindrical thermal energy storage (TES) system for particle-based concentrated solar power (CSP) applications. The skip-hoist PL, constructed with stainless steel for high-temperature compatibility, was seamlessly integrated with two TES bins on a 22-m concrete tower. Preliminary testing at ambient temperature confirmed the system’s operational feasibility, paving the way for high-temperature testing and the proposed 1.3 MWe pre-commercial scale-up in Waad Al-Shamal, Saudi Arabia.
Copyright (c) 2025 Nader Saleh, Shaker Alaqel , Eldwin Djajadiwinata , Rageh Saeed , Hany Al-Ansary , Zeyad Al-Suhaibani , Abdelrahman El-Leathy, Syed Danish, Sheldon Jeter https://creativecommons.org/licenses/by/4.0
Current Progress of Activities at EU-SOLARIS ERIC: The European Research Infrastructure Consortium for CSP Technologies
An ERIC, established by a decision of the European Commission, is a legal entity possessing legal personality and full legal capacity acknowledged across all EU Member States. Its primary role is to establish and operate a research infrastructure on a non-economic basis. Under the initiative of Spain, France, Germany, and Cyprus as Members, with Portugal as an Observer, a European Research Infrastructure Consortium (ERIC) has been formed. This consortium, named "European Solar Research Infrastructure for Concentrated Solar Power" (EU-SOLARIS ERIC) is established in accordance with Council Regulation (EC) No. 723/2009 of 25 June 2009. The establishment of an ERIC was sanctioned by the European Commission, as evidenced in Commission Implementing Decision (EU) 2022/2297 of 19 October 2022 [1]. The inaugural assembly of the EU-SOLARIS ERIC took place at the CIEMAT Headquarters in Madrid on 12th January 2023. During this gathering, the General Assembly was officially convened, and the Statutes along with other governing documents were formally endorsed. At the time of composing this document, negotiations for the accession of three additional countries—Greece, Turkey, and Italy—are underway. This paper summarizes the R&D activities carried out during this first year of the ERIC, particularly, we describe the new projects achieved.
Copyright (c) 2025 Ricardo Sánchez, Julián Blanco, Emmanuel Guillot, Gilles Flamant, Manuel Blanco, Daniel Benitez, Marios Georgiou, Nestor Fylaktos, Joao Cardoso, Diogo Canavarro, José Martín, Diego Martinez https://creativecommons.org/licenses/by/4.0
CST4ALL - Support to the Activities of the Concentrated Solar Thermal Technology Area of the SET Plan
The Concentrated Solar Thermal Technologies (CST) sector has struggled with high-costs associated with Concentrated Solar Power (CSP) plants in Europe over the past decade. Moreover, CSP has largely been viewed only as a flexibility provider for electricity systems. To address these challenges, the CST4ALL project promotes a range of hybridization and cooperation initiatives at the intersection of CST and other renewable energy technologies, drawing on the work of various European Technology & Innovation Platforms (ETIPs). CST4ALL aligns closely with current EU priorities- such as Smart Sector Integration, Fit for 55, and Clean Energy Transition Partnership (CETP)-as well as national energy strategies. It seeks to offer solutions to pressing issues related to decarbonisation and energy security. The key outcome is a series of workshops engaging both industry and research and development (R&D) communities, fostering interaction among stakeholders at key technology interfaces with the CST sector. By analysing both industrial and R&D perspectives, CST4ALL aims to expand the network of active stakeholders in the CST Implementation Working Group (IWG) under the SET Plan and to raise awareness of CST’s potential role in sustainable energy mix. This paper outlines the project’s main activities to support the European Commission’s cross sector approach – encouraging public and private investment in R&D and establishing the political and regulatory framework needed to implement the new CST Implementation Plan (IP) from October 2022 to March 2024.
Copyright (c) 2025 Yelda Erden Topal, Hande Eryılmaz, Derek Baker, Konstantinos Genikomsakis, Peter Heller, Daniel Benitez, Julian Blanco Galves, Ricardo Sanchez, Luca Turchetti, Simona De Iuliis, Alperen Gunay https://creativecommons.org/licenses/by/4.0
Optical Fiber as Solar Radiation Collector for Radiometric Measurements
The feasibility of using optical fibers as solar radiation collectors in radiometric measurement devices and instruments is discussed, taking into account the various characteristics of the fibers that affect the measurements, with a special focus on numerical aperture. The discussion is supported by various results using the fiber to measure direct normal irradiance.
Copyright (c) 2025 Manuel Jerez, Alejandro Carballar, Joaquín Granado https://creativecommons.org/licenses/by/4.0
Opto-Electronic Sensor for HTF Early Leak Detection Based on Infrared Absorption
We propose an early leak detection sensor for HTF (Heat Transfer Fluid) leakages by measuring the absorption of infrared radiation by the HTF components. This sensor, that can be installed inside the insulation around ball joints or other elements in a Concentrated Solar Power (CSP) plant, detects leaks by sensing mid-infrared absorption at specific wavelengths. The sensor includes a reference signal to correct for external factors like temperature changes and sensor degradation. Laboratory tests have validated the sensor performance under various conditions. The sensor enhances the sustainability of solar thermal plants by providing early leak detection and is easily adjustable for different HTFs by changing the IR (Infrared) radiation sensing bands.
Copyright (c) 2025 David Izquierdo, Maria Heras, Cristina Pelayo, Adrián Peña, Marcelino Sánchez https://creativecommons.org/licenses/by/4.0
Advanced Drone-Based Alignment Measurements for Parabolic Trough Collectors
A novel drone-based measurement method for the automatic quality check of the field assembly of parabolic trough collectors has been developed. The module as well as receiver alignment of entire parabolic trough loops can be measured using commercially available drones equipped with a visual camera and RTK (real time kinematic) positioning. The measurement principle is based on the geometric relations between aperture edges of the parabolic trough collector and the absorber tube line, which both are measured seamlessly along the collector using robust edge detection algorithms. The measurement method replaces hook-rod based measurements of the receiver alignment and total-station based measurements of the module alignment in a fast and fully automated way while keeping high measurement resolution and accuracy. Due to its speed and versatility to measure receivers with and without protective foil and with the collector in arbitrary orientation, the measurement method can be applied in all project phases ranging from solar field construction over commissioning to operation. The paper presents the progress in the development of the method and the results of the validation measurements performed at the parabolic trough collector loop of the molten salt test platform (EMSP) in Évora, Portugal.
Copyright (c) 2025 Andreas Kämpgen, David Helten, Klaus Pottler, Marc Röger https://creativecommons.org/licenses/by/4.0
Design and Operation of Hybrid CSP-PV-Wind Plants Operating on the Italian Day-Ahead Electricity Market and on the Ancillary Services Market
Concentrating Solar Power equipped with Thermal Energy Storage (TES) allows for dispatchable power production, but the worldwide installed power is still limited due to its higher investment costs with respect to other renewable technologies. A promising option to reduce costs, while keeping a high dispatchability level, is the hybridization of CSP with Photovoltaic (PV) and wind turbine (WT) plants. Hybrid CSP-PV-Wind plants have already shown their capability to achieve higher dispatchability level and lower costs with respect to stand-alone CSP, PV and wind plants. This work investigates the techno-economic optimization of hybrid CSP-PV-Wind plants capable of operating on both the Day Ahead Market (DAM) and the Ancillary Services Market (ASM), assuming different market scenarios. The design and operation of the hybrid plant are co-optimized using the optimization framework developed by Politecnico di Milano and considering the simultaneous participation of such plant to the DAM and ASM Italian markets. Results showed that while a price multiplier of 4 should be applied to the current spot market prices to make the hybrid plant economically viable in the DAM market, a price multiplier of 2 is sufficient for a positive NPV when also the revenues from the ASM market are considered. Moreover, the CSP turn out to be an essential flexibility provider: conversely to the solution combining PV and WT with a battery storage, CSP-based configurations avoid the need for a large battery for the reserve provision, with a significant economic benefit on the plant NPV.
Copyright (c) 2025 Lorenzo Pilotti, Giampaolo Manzolini, Walter Gaggioli, Antonio Guglielmo, Emanuele Martelli, Marco Binotti https://creativecommons.org/licenses/by/4.0
Hedging Risk in Techno-Economic Assessment for CSP Plants Through Synthesis of One-Minute Irradiance Series
For the proper sizing of a solar plant, thorough simulations are performed to obtain the optimum configuration for the optimization objective, such as to minimize the Levelized Cost of Energy. These simulations consider the use of a Typical Meteorological Year, that condenses in a single year the long-term meteorological characteristics. These data sets are often derived from satellite estimates and validated against ground measurements taken over a shorter period of time. One issue with these data sets is concerned with temporal resolution, as they are limited by the capacity of the satellite to resolve phenomena on a temporal scale. This results in a loss of high-frequency detail that could affect the techno-economic design and assessment of a solar plant, creating uncertainty in the expected performance when compared to ground data, thus increasing project risk. This work explores the effect of applying a temporal downscaling technique to generate one-minute estimates of ground radiation from hourly satellite data in the reduction of uncertainty in technical and economic key performance indicators. A Concentrated Solar Power plant of 100MWe and 12 hours of storage is studied and results are compared to determine the extent to which temporal downscaling allows to hedge estimation of performance and in turn, risk. Results show that while the most significant source of uncertainty is the estimation error inherent to the satellite procedure, temporal downscaling allows for a reduction of 2.1% in LCOE estimation, showing that a relatively simple post-processing procedure allows for a measureable reduction in investment risk.
Copyright (c) 2025 Armando Castillejo-Cuberos, Ignacio Arias, José Cardemil, Rodrigo Escobar https://creativecommons.org/licenses/by/4.0
Techno-Economic Analysis of a Solar Calciner for CO2 Emissions Reduction in the Chilean Cement Industry
Clinker, constituting approximately 72% of cement's composition, is produced through an energy-intensive process that significantly contributes to CO2 emissions. This study explores the integration of a solar calciner into the Chilean cement industry, particularly in the Antofagasta region, which is characterized by high solar energy irradiation, with an annual DNI of 3,250 kWh/m2. This region also accounts for approximately 30% of the country's cement sector energy consumption. In this context, this study evaluates two Concentrated Solar Thermal (CST) scenarios: the Top of Tower (TT) system and the Beam-down (BD) system, assessing their technical and economic feasibility for reducing CO2 emissions in the calcination process. The findings suggest that both CST systems could substantially reduce CO2 emissions in the calciner. However, economic feasibility remains a challenge, primarily due to the low cost of coal, which is the main fuel in the Chilean cement industry. Additionally, the efficiency of the solar calciner is found to be crucial for achieving maximum emission reductions, for the scalability of the technology, and for its future adoption in Chile's cement industry. Although the Levelized Cost of Heat (LCOH) for the proposed plants is currently higher than the coal-fired calciners in which is produced about 90% of current clinker production in Chile, potential reductions in heliostat costs, coupled with an increase in carbon taxes beyond the current value of 5 USD/tCO2, could significantly improve the economic viability of CST plants in Chile's cement industry.
Copyright (c) 2025 Juan Sebastian Zuleta Marin, Gregor Bern, Frank Dinter, Werner Platzer https://creativecommons.org/licenses/by/4.0
Design Data for Alloy 282 High Temperature Concentrating Solar Power Components
New design rules for high temperature concentrating solar power metallic components have been proposed recently. These rules are to be used in conjunction with the Section III, Division 5 rules of the ASME Boiler & Pressure Vessel Code and include three design by analysis options. In this paper, we report the corresponding design data for a nickel-based high temperature alloy – Alloy 282. The current Alloy 282 Code Case includes some basic material properties such as Young’s modulus, Poisson’s ratio, thermal properties, yield strength, tensile strength, and allowable stress So. However, a complete design check for high temperature components requires additional material data including allowable stress Sm, isochronous stress-strain curves, minimum-stress-to-rupture, fatigue diagrams, and creep-fatigue damage envelope. We construct these design data from the available material data in the literature and data generated recently at Idaho National Laboratory. We also develop an inelastic constitutive model for use with the design by inelastic analysis method.
Copyright (c) 2025 Bipul Barua, Mark C. Messner, Michael D. McMurtrey https://creativecommons.org/licenses/by/4.0
Model Sensitivity Analysis of Lifetime Predictions for Generation 3 Particle-sCO2 Heat Exchangers
A sensitivity analysis is performed to determine which variables play a first order role in determining the lifetime of particle-sCO2 heat exchangers. A symmetric half-plate geometry based on a hypothetical 16.7 MW commercial scale particle-sCO2 diffusion bonded IN617 heat exchanger is studied. A reduced-order modelling approach is presented and the steady-state and transient thermal and mechanical performances under nominal Generation 3 concentrated solar power operating conditions are compared against the fully featured model. The defeatured model shows the ability to accurately predict the thermal performance and mechanical lifetime at a fraction of the computational cost, making it a viable option for analysing commercial scale systems. Seven of the model input variables are then parameterized using a Latin Hypercube Sampling method and up to 128 different realizations are simulated. The transient stress results are linearized along stress classification lines in the header ports and used to predict the number of cycles to failure due to fatigue and creep. Sobol indices are generated to relate the cycles to failure to the independent variables studied. The results show that the uncertainty in the creep cycles to rupture data dominates the variation in lifetime predictions.
Copyright (c) 2025 Christopher Bowen, Matthew Sandlin https://creativecommons.org/licenses/by/4.0
Simulation of a Hybrid Concentrated Solar and Biomass-Fuelled Trigeneration System for Residential Applications
Solar technologies stand out as effective solutions for decarbonising the building sector. Among them, Concentrated Solar Power (CSP) systems offer the advantage of delivering flexible and dispatchable power. However, hybridisation with other renewable energy sources is often pursued to extend the operational hours. Therefore, this study investigates the complementarity of solar energy with biomass combustion within a small-scale hybrid trigenerative plant. More precisely, the proposed system consists of a 240 kWth peak thermal power Linear Fresnel Reflectors solar field combined with a 130 kWth back-up biomass boiler to supply heat to a 20 kWel/100 kWth Organic Rankine Cycle (ORC) unit for the provision of cooling, heating and electric power to 10 apartments. The hybrid plant also integrates thermal energy storage tanks and a battery energy system to increase the solar energy self-consumption and reduce the intervention of the grid. The performance of the hybrid system is analysed through an advanced simulator developed by the authors in MATLAB/Simulink considering the components’ inertia. The results reveal an increment in solar energy self-consumption achieved by exploiting the low solar irradiance to bring the latent heat thermal energy storage into its melting range, thereby extending ORC operation into nighttime hours. More precisely, the system meets the entire annual thermal demand for space heating, cooling and domestic hot water through renewable sources, consuming 2.25 tons of biomass. Electric demand coverage, instead, reaches up to 81% with the inclusion of a 60 kWhel battery energy storage system.
Copyright (c) 2025 Luca Cioccolanti, Greta Lombardi, Luca Del Zotto, Pietro Elia Campana https://creativecommons.org/licenses/by/4.0
Comparative Techno-Economic Analysis of Different Parabolic Trough CSP Plants for the Italian Market
The objective of this study is to present updated estimates of the cost of concentrated solar power (CSP) projects that are relevant for the current Italian market. To this end, a comparative techno-economic analysis of different CSP plant types based on parabolic trough (PT) collectors was conducted, considering various scenarios with respect to heat transfer fluids, location and storage size. The scenarios were defined in accordance with a number of requirements, including the utilization of technologies produced in Europe (in alignment with the EU's Net-Zero Industry Act), the availability of performance and cost data from existing literature, and/or the authors' own experience, as well as the eligibility for incentives according to the initial drafts of the new support measure. The analysis employed two distinct modelling tools, developed by ENEA and DLR, respectively. These offered varying levels of detail in the description of the plant behavior. Thus, cross-checking of the results was enabled. Additionally, insights were gained concerning the impact of the chosen modelling approach on performance assessment.
Copyright (c) 2025 Walter Gaggioli, Marco D'Auria, Valeria Russo, Simona De Iuliis, Luca Turchetti, Jürgen Dersch, Michael Wittmann, Tobias Hirsch, Jana Stengler https://creativecommons.org/licenses/by/4.0
Techno-Economic Analysis on Optimum Size of a Heliostat for High-Temperature Applications
This study investigates the impact of heliostat size on the levelized cost of heat (LCOH) and explores the trade-off between performance and cost for a baseline 160 MWth concentrating solar thermal (CST) tower system at high temperatures (565°C – 1550°C). The analysis assumes blackbody radiation for thermal losses at the receiver and employs ray tracing to assess optical losses in the heliostat field. A surrogate cost model is used to break down component costs for a specific commercial heliostat design (i.e., SunRing), considering volume production and operations and maintenance (O&M) costs to determine installation costs. The results indicate that heliostat size significantly affects the LCOH at different temperatures, with installation costs being a crucial factor in determining the optimal heliostat size. These installation costs vary by temperature and plant size due to power requirements and volume production considerations. The results motivate ongoing research to further refine the cost model and explore the projects of different sizes.
Copyright (c) 2025 Ahmed Gamil, Alexander Zolan, Chad Augustine, Guangdong Zhu, Kenneth Armijo https://creativecommons.org/licenses/by/4.0
Application of Molten Salt Electrical Heaters to Increase the Flexibility of CSP Plants’ Power Block
The transforming grid profiles require concentrated solar power (CSP) plants to operate in a dispatchable and flexible manner; however, the allowable minimum load of the power block exerts a limitation on the operation range. This study proposes using molten salt electrical heaters to lower the minimum electricity output of CSP plants. In this regard, three configurations of the molten salt electrical heaters, 1) in parallel to the receiver, 2) in parallel to the hot tank, and 3) in series to the receiver, are investigated with six grid and three revenue scenarios. The system is assessed for Fuerteventura. The findings validate that the application of the molten salt electrical heaters, particularly through Configurations 1 and 3, enhances a) the flexibility characteristics of the CSP plant with up to a 10.2% increase in demand coverage factor, an 84.6% decrease in start-up instances, and a 41.4% increase in operating hours; and b) economic performance with up to a 35.7% increase in gross profit.
Copyright (c) 2025 Eylül Gedik, Johannes Werner, Manfred Wirsum https://creativecommons.org/licenses/by/4.0
Multi-Flow Falling Particle Receiver Modeling
Generation 3 Concentrating Solar Power systems use solid particles for heat transfer and thermal energy storage. Particle-based systems use a falling particle receiver with an open cavity where particles flow together as a curtain that is directly exposed to solar radiation absorbed by the particles as they descend. The efficiency of the receiver depends on curtain opacity (influenced by the particle mass flow rate), the average particle temperature, and environmental factors. We present a free-falling particle receiver design that incorporates ten individually controlled valves for precise particle supply management. Each valve is equipped with a slide gate and an actuator, ensuring a consistent mass flow rate. In a uniform mass flow rate curtain, the hottest particles accumulate in the center due to non-uniform flux distribution, leading to higher radiative and advective losses. Accordingly, lower flux levels at the periphery result in lower temperature particles. Our modular valve design enhances receiver efficiency by improving curtain opacity in key areas. The outer valves have the lowest mass flow rate, while the center valves have the highest, allowing more uniform heating. The 10-section model outperforms the 1D model by reaching a maximum efficiency of 85%, compared to 84%.
Copyright (c) 2025 Ahmed Mohamed, Gowtham Mohan, Peter Vorobieff, Nathan Schroeder https://creativecommons.org/licenses/by/4.0
Assessment of Self-Dispatch Strategy in a Concentrating Solar Power System: Impact Analysis on the Chilean Spot Electricity Market
This study investigates the technical and economic impacts of self-dispatch strategies on Concentrated Solar Power (CSP) plants in Chile’s spot electricity market. The PySAM simulation tool was used to model three dispatch scenarios—Marginal Cost-Responsive Dispatch, Daytime Mandated Dispatch, and Continuous Base Load Dispatch—to assess their effects on energy production, load factors, and financial outcomes at the Crucero and Cardones substations. The findings indicate that the Marginal Cost-Responsive Dispatch strategy optimizes revenue by aligning energy generation with periods of higher market prices. This strategy mitigates the adverse financial impacts of zero-marginal-cost periods, which undermine the viability of more rigid approaches like Daytime Mandated Dispatch. Economic analysis shows that only the Marginal Cost-Responsive Dispatch consistently covers annualized capital expenditures (CAPEX), particularly at lower CAPEX levels. In contrast, the alternative scenarios fail to achieve financial sustainability due to forced generation during low-value periods. Consequently, these results underscore the crucial role of dispatch flexibility in enhancing the economic performance of CSP plants. The study suggests that market regulations should be revised to encourage strategies that enable CSP plants to dynamically respond to market conditions, supporting the broader integration of CSP technology into Chile’s energy market. Such adjustments are crucial for advancing the country’s decarbonization goals. Future research should focus on further developing advanced self-dispatch algorithms and hybrid CSP systems to optimize economic outcomes in increasingly dynamic market environments.
Copyright (c) 2025 Francisco Moraga, Carlos Felbol, Maria Teresa Cerda, Frank Dinter https://creativecommons.org/licenses/by/4.0
Upscaling and Testing of Air-Based Rotary Solar Thermal Receivers for Concentrated Solar Power Applications
Odqa Renewable Energy Technologies Ltd has successfully scaled its air-based rotary solar thermal receiver design from 10kW to 100kW. A 10kW-scale air-based rotary solar thermal receiver was tested in Odqa’s in-house solar simulator facility in late-2022. Learning from the experience, an improved solar thermal receiver rotor geometry has been developed and built, its mechanical design has been proven in a heliostat field test carried out at PROTEAS, The Cyprus Institute. A Predictive Engineering Analytics approach has been developed to predict the thermal performance and for the purpose of upscaling of the solar thermal receiver. As a result, the thermal design for a 100kW-scale solar thermal receiver has been produced, which subsequently was built at Odqa and tested at the SynLight solar simulator facility at the Institute of Solar Research, German Aerospace Center (DLR).
Copyright (c) 2025 Pok-Wang Kwan, Mark Loasby, Augustin Wambarsie, Chiang Churchill Ngai, Peter T. Ireland, Joe Baddeley, Katarina Marčeta, Orla Mallon, Asli Kaya, Dave Mountain, Scott Battams, Ashley Cooper, MyeongGeun Choi, George Wilson, Kirk Ashley-Morgan, Gediz Karaca https://creativecommons.org/licenses/by/4.0
Review of the Operational Phase of the South African Concentrated Solar Power Projects
This paper provides an overview of the six Concentrated Solar Power (CSP) projects in operation in South Africa, comprising 500 MW generation capacity. These projects, in addition to the seventh (100 MW) CSP project currently in construction, were awarded under various bid windows of the Renewable Energy Independent Power Producer’s Procurement Programme (REIPPPP) and commenced operations during 2015-2019. Key operational data up to the end of 2023 are presented, as of when the combined cumulative electricity generation by the six CSP projects reached 10.1 TWh. This represents approximately 81% of the sum of the P50 Energy Yield Forecasts (EYFs) in the respective project Power Purchase Agreements (PPAs), and 9.6% of all electricity generated by the REIPPPP projects by the end of 2023, while the CSP projects constitute 8.1% of total installed capacity (6180 MW) as of December 2023. Factors affecting performance are discussed, including meteorology and outages. Consumption of major utilities is also discussed, comparing to expected values or limits.
Copyright (c) 2025 Jacobus van Zyl, Prinavin Perumal, Alberto Cuellar https://creativecommons.org/licenses/by/4.0
Effect of Compressor Inlet Swirl on Solar Gas Turbine Performance
An investigation of the effect of various compressor inlet guide vane (IGV) setting angles on the thermodynamic performance of a simple single shaft solar-hybrid gas turbine power generation system (SHGT) is presented. The formulation of models for the individual system components is described, with emphasis on the generation of compressor characteristics for various IGV setting angles. Matching of the components in the integrated system model is shown, for the standard single shaft turboshaft configuration as well as several variable rotor speed turboshaft configurations. The estimated fuel consumption, solar receiver effectiveness, and thermal efficiency are compared for the reference system, SHGTs with IGVs, and variable rotor speed SHGT configurations. The results of the performance calculations for a 40 kWe gas turbine engine indicate that a 4.3 % reduction in full-load fuel consumption is attainable with compressor IGVs set at 9° in the direction of the rotor blade rotation, and a reduction of 25.3 % is attainable with independent and distinct compressor and turbine rotor speeds.
Copyright (c) 2025 Matthew Meas, Johan van der Spuy, Andrew Gill https://creativecommons.org/licenses/by/4.0
Factor Estimation for Accounting Dynamic Start-Up Effects in Solar Heat Plants Using Quasi-Static Modeling
Solar heat plants represent a promising solution to decarbonize the industry. However, the industry is reluctant to adopt this technology, largely due to concerns regarding the variability of solar resources. Early-stage projects rely heavily on annual simulation models to inform decision-making processes, underscoring the critical need for accurate predictions of solar plant energy yield. To address this, a methodology has been developed to enhance the precision of heat production estimates in annual steady-state modelling by integrating dynamic effects through the introduction of a heat-up factor. This heat-up factor will be dependent on the initial temperature, the DNI conditions, the heat capacitance of the installation, and the chosen control strategy. The findings demonstrate a significant enhancement in the accuracy of steady-state model simulations with the inclusion of the heat-up factor, effectively capturing the dynamic influence on energy consumption during start-up.
Copyright (c) 2025 Magdalena Barnetche, Tim Kotzab, Tobias Hirsch, Robert Pitz-Paal https://creativecommons.org/licenses/by/4.0
Numerical Modelling of a Solar Thermochemical Heat Transformer for Industrial Heating Applications
Replacing fossil fuel-based industrial heating systems with sustainable alternatives such as solar thermal systems is necessary for achieving sustainable development goals. Often low-concentrated solar collectors are cheaper yet their low-temperature output limits their applications in the industry. The thermochemical heat transformers can be integrated with these collectors to achieve an upgraded output temperature without electricity consumption. Furthermore, these thermochemical systems have an inherent capability of heat storage in chemical bonds thereby mitigating the intermittency issue of solar energy sources. In this research, an innovative packed-bed thermochemical reactor in a closed system configuration is introduced and simulated numerically. The main objective of this analysis is to scrutinize how well the proposed design operates in terms of heat and mass transfer. In this reactor, SrBr2 hydrate is used as the thermochemical material. The study indicates that the proposed design can potentially upgrade the temperature by 100 °C and maintain it at 300 °C for about 40 minutes. This modular design, which can be scaled up easily for large applications, predicts the full conversion of reactions and shows a flexible temperature boost of low-concentrated collectors output.
Copyright (c) 2025 Ramin Roushenas, Marco Ballatore, Artem Sybir, Aldo Cosquillo, Marc Linder, Abhishek K. Singh https://creativecommons.org/licenses/by/4.0
A Techno-Economic Comparison of CST and Conventional Cooking Technologies in West Africa
Clean and affordable cooking remains a critical challenge in sub-Saharan Africa, where traditional biomass-based methods create health, environmental, and economic burdens. This study compares the economic viability of Concentrated Solar Thermal (CST) cookers, Fresnel Lens and Parabolic Trough Collector (PTC), with traditional charcoal stoves in rural Nigeria and Ghana using the Levelized Cost of Cooking a Meal (LCCM). While charcoal stoves offer the lowest short-term cost ($0.07628/meal), CST cookers become more economical over time, with the Fresnel Lens achieving an LCCM of $0.1432/meal over a 30-year lifespan. The PTC offers flexibility but has a higher cost due to its advanced design. The study emphasizes the potential health and environmental benefits of CST cookers, along with policy recommendations for overcoming adoption barriers through subsidies and innovative financing.
Copyright (c) 2025 Zaharaddeen Ali Hussaini, Mounia Karim, Khalifa Aliyu Ibrahim, Zhenhua Luo, Christopher Sansom, Tugba Gurler, Johnson Okeniyi, David Akraka, Saifullah Ali https://creativecommons.org/licenses/by/4.0
Solar Heat for Commodity Production: Mapping and Comparison With Fossil Fuel and PV
A systematic assessment of concentrated solar thermal (CST) energy and its levelized cost of heat (LCOH) is essential to demonstrate the global potential of CST-energy for decarbonizing industrial heat demand – especially, since time is running out to tackle climate change and a significant part of industrial heat demand can be covered with CST as solar heat for industrial processes (SHIP). For this study, CST-LCOH in dependence of the DNI (direct normal irradiance) are obtained from literature as the annual energy yield changes with DNI and thus, the LCOH changes accordingly. These are mapped for Spain and compared locally with fossil fuel- as well as PV-based heat. A sensitivity analysis is performed for CST-LCOH, varying it by ±10 %, and including an implementation of CO2-taxes of 0, 50 and 100 €/t CO2 for the fossil fuels coal and natural gas. In all cases, if a renewable source is cheaper than fossil fuels, it is overwhelmingly CST. The margin for CST-energy, obtained as the difference of fossil fuel price with CST-LCOH, divided by CST-LCOH and which can also be interpreted as the relative margin from CST-LCOH to -price, reaches in the extreme case 139 % for fossil fuel prices in 2022 and a CO2-tax of 100 €/t CO2.
Copyright (c) 2025 Gkiokchan Moumin, Riccardo Cuneo, Nicole Carina Neumann https://creativecommons.org/licenses/by/4.0
Hybrid Concentrated Solar Thermal and Wind Resistive Heating Systems as Key for Competitive Low Emission Industrial Process Heat Generation
Concentrated Solar Thermal (CST) has been addressed as a promising technology for industrial heat decarbonization; however, its use is still limited to low-medium temperature processes (50-250°C). The following analysis explores its feasibility at high temperature employing a parabolic trough solar field with a direct two-tank storage configuration using molten salts both as heat transfer fluid and storage medium, to provide a constant 10 MWTH power to heat up a process fluid to 500°C. Through an economic optimization, various levels of process decarbonization are examined, also including CST hybridization with resistive electric heating powered by photovoltaic and wind energy generation and computing CO2 emissions on a life cycle assessment (LCA) basis. The results indicate that CST is a viable alternative to direct electrification up to 30-50% process decarbonization, while hybrid systems show potential to reduce costs up to 40% at high decarbonization levels. Moreover, although achieving 100% process decarbonization remains still unfeasible, decarbonization levels up to 80-95% appear economically viable when considering up-to-date costs and the forecasted carbon tax.
Copyright (c) 2025 Marco Colombi, Paolo Colbertaldo, Matteo Carmelo Romano, Marco Binotti https://creativecommons.org/licenses/by/4.0
Acceptance of a Solar Field Composed of Small-Size PTC Applying to Standard ISO 24194
The verification of solar field performance is possible through international standards EN ISO 24194 since 2022 and using results of standard ISO 9806 from the collector testing previously. However, for concentrating solar collectors this verification is not always done by the industry, and the large-size collector efficiency are guaranteed by the contractor from different components separately or a test done in an existing facility.
Copyright (c) 2025 Fabienne Sallaberry, Alberto García de Jalón, Roberto Astiz, Egoitz San Miguel Carrancio https://creativecommons.org/licenses/by/4.0
Design of an Air-Fed PTC Solar Field Integrated With a Rock Bed-Based Thermal Energy Storage System
Integrating solar energy to provide heat for industrial processes represents a viable solution aligned with the ongoing energy transition. Parabolic trough collectors (PTCs) are a reliable and mature technology within this context. This study addresses the performance of an industrial air-drying plant integrated with a PTC solar field and a thermal energy storage (TES) system comprising two rock beds operating in parallel. To improve the exploitation of solar radiation, pressurized air was used as the heat transfer fluid for the PTC due to its high temperature limits. A parametric analysis was conducted to evaluate the impact of solar field size on performance, varying both the number of modules in series per string and the number of parallel strings. Results show that the solar fraction (SF) increases with the number of parallel strings, while increasing the number of series modules initially raises the SF to a peak before slightly decreasing. The maximum SF achieved was 85% with a TES volume of 96.24 m³ and a solar field comprising 12 modules in series and 4 parallel strings, resulting in a total collection area of 3450 m².
Copyright (c) 2025 Antonio Cristaudo, Francesco Nicoletti, Francesco Rovense, Walter Gaggioli, Vittorio Ferraro, Natale Arcuri https://creativecommons.org/licenses/by/4.0
Precalciner Geometry Optimization Considering H2O and CO2 Heat Transfer Fluid for Cement Production
The cement industry accounts for 3 – 5% of global CO2 emissions and is difficult to decarbonize due to the high temperature used in the process. The cement raw material requires temperatures up to 900 ℃ for calcination and 1500 ℃ for sintering. Synhelion has developed an absorbing-gas solar receiver which can provide 1500 °C heat to the process via an H2O/CO2 heat transfer fluid to provide fossil-free heating for the preheating and calcination stages. However, very little work has been done to investigate the viability of solar-heated H2O and CO2 gases to efficiently calcine the cement raw meal relative to conventional gas-fired precalciners. The objective of this study is to present an optimized small scale precalciner considering particle suspension, flow dynamics, heat transfer, and thermochemistry of the raw meal when using H2O and CO2 gases. The optimization of the precalciner geometry using a CFD model developed in ANSYS is presented.
Copyright (c) 2025 Javier Martell, Brantley Mills, Nathan Schroeder https://creativecommons.org/licenses/by/4.0
Assessment of Small-Scale Parabolic Trough Collectors for Integration in Industrial Process Heat
This study deals with the preliminary analysis of a small-scale Parabolic Trough Collector (PTC) installed on a rooftop at an industrial complex for the production of process heat. Four scenarios, featuring Heat Transfer Fluid (HTF) outlet temperatures from the PTC of 120°C, 150°C, 200°C, and 250°C, were assessed, varying both collector surfaces and storage capacities; the Levelized Cost of Heat (LCOH) was evaluated for each configuration. The analysis considered data from a commercially available PTC, selected based on a survey among research and industrial partners, and integrated into the System Advisor Model (SAM) libraries. Meteorological data from a North Italian site, characterized by a low annual DNI value, was also considered, assuming this location for the solar plant installation. Economic evaluations employed both literature reviews and real-component purchase price assessments conducted by the partnership. The findings suggest that a LCOH between 4.30 and 4.83 c€/kWh is achievable, with the HTF outlet PTC temperature of 200°C emerging as the scenario allowing for the lowest LCOH due to its balance between the costs of the plant, particularly those related to storage systems, and the thermal energy output.
Copyright (c) 2025 Francesco Rovense, Walter Gaggioli, Fabio Grisoni, Marco Rottoli, Maurizio De Lucia, Leonardo Nibbi, Michele Salvestroni, Filippo Cottone https://creativecommons.org/licenses/by/4.0
Evaluating the Potential of Solar Heat Production for the Food and Beverage Industry in Cyprus From 2024 to 2035
The increasing heat demand in Cyprus' F&B industry presents an opportunity to leverage the abundant solar resources of the country as a sustainable alternative to fossil fuels for industrial processes. To project the final energy consumption (FEC) of the national F&B industry from 2024 to 2035, the GDP (PPP) is used as an exogenous variable. A regression model is obtained with an adjusted correlation coefficient (R²) of 85.8%. For the projections, two economic growth scenarios are considered (positive, PEG, [+3%] and negative, NEG, [−1.5%]), combined with two scenarios for solar technology deployment (business-as-usual, BAU, [2%] and large, LTD, [20%]). Additionally, dynamic simulations in TRNSYS are conducted to estimate the annual yield of a model SHIP plant using Parabolic Trough Collectors. The modelled system, consisting of a total collector area of 660 m² and a thermal storage of 30 m³, yielded 4,320 MJ/m² of thermal energy. It was found that solar energy could uptake between 10% and 28% of the FEC for the NEG and PEG scenarios, respectively. Moreover, the solar heat potential ranged between 85 TJ and 444 TJ, which represents between 19,780 m² and 102,800 m² of solar collectors, respectively. Lastly, the projections also analyse the reduction of GHG emissions in 2035 compared with the baseline year (2023), where the NEG-LTD scenario achieved a reduction of 71%; meanwhile, the PEG-BAU scenario presented an increment of 25% in the GHG emissions.
Copyright (c) 2025 Juan Pablo Santana, Antonio Arto Delgado, Abel Climente García, Ivan Acosta-Pazmiño, João Gomes https://creativecommons.org/licenses/by/4.0
Experimental Investigation of Heat Losses in Hydrogen-Doped Parabolic Trough Receivers
This study investigates the impact of hydrogen presence in the annulus space of heat-collecting elements (HCEs) used in parabolic trough solar power plants. Hydrogen, formed during degradation of the heat transfer fluid diphenyl oxide/biphenyl (DPO/BP), can permeate into the annulus and significantly increases heat loss due to enhanced conductive heat transfer. Following the resistance heating method defined tin the technical specification IEC TS 62862-3-3, heat loss measurements were conducted on HCEs before and after hydrogen doping at various absorber temperatures (100–400 °C). Results showed heat losses up to four times higher in hydrogen-doped receivers, reaching 867 W/m at 400 °C, compared to 211 W/m in evacuated units. Uncertainty analysis confirmed measurement reliability. The data confirms hydrogen’s detrimental effect on thermal performance and supports the need for improved hydrogen control in operational solar power plants with parabolic troughs.
Copyright (c) 2025 Loreto Valenzuela, Rafael López-Martín, Carmen M. Amador-Cortés, Christoph Hilgert https://creativecommons.org/licenses/by/4.0
Numerical Prediction of the Initial Heating of Granular Material Treatment Using a Solar Rotary Kiln
Recent studies have proposed rotary kilns as solar receivers or reactors for industrial applications and for thermal storage. However, few investigations have focused on the temperature distribution within the particle bed, which is crucial for understanding system performance and developing optimization strategies. This work presents a comprehensive study of a lab-scale rotary kiln coupled with a high-flux solar simulator, examining the initial seconds of heating inert alumina spheres. Experimental data are compared and integrated with a two-dimensional thermo-fluid dynamic model using an Eulerian continuum approach. The model was initially validated for static particle heating and subsequently applied to simulate a rotating case, predicting temperature distribution in the transversal section of the granular bed. The results demonstrate the significant impact of rotation on homogenizing bed temperature and reducing thermal gradients. When the bed core reaches approximately 180°C, the maximum temperature difference between the center and sides is less than 50°C for the rotating configuration, compared to over 110°C for the static setup. This study provides valuable insights into the thermal behavior of rotary kilns as solar receivers, contributing to the optimization of their design and operation for various industrial and energy storage applications.
Copyright (c) 2025 Alessandro Gallo, Elisa Alonso Romero, María Isabel Roldán Serrano https://creativecommons.org/licenses/by/4.0
Development of a Small Punch Test to Evaluate Liquid Metal Embrittlement Susceptibility of 316L Stainless Steel in Liquid Sodium
Liquid sodium is proposed as a heat transfer fluid for solar thermal power receiver designs. It has a long history of use for heat transfer in various industries, with extensive knowledge of its impact on the structural integrity of materials at temperatures ranging from 300 ℃ to 800 ℃. However, the effects at lower temperatures are more poorly understood, which is crucial to studying solar thermal power plant systems. These systems experience diurnal cyclic temperature variation, which causes significant fluctuations in the operating temperature of liquid sodium. Several studies have demonstrated that the susceptibility of metals to Liquid Metal Embrittlement (LME) is highest at temperatures close to the melting point of the liquid metal. Therefore, this study investigates the susceptibility of 316L stainless steel, a common construction material, to sodium induced LME at temperatures between 100 ℃ to 300 ℃ using the Small Punch Test (SPT) method. The test apparatus was validated by using a known embrittling pair of Brass-Galinstan between 10 ℃ to 43 ℃, where the test revealed the expected LME susceptibility of brass. However, no evidence of LME was found in the 316L-sodium pair at temperatures up to 300 ℃.
Copyright (c) 2025 Stuart Bell, Gaurav Vithalani, Richard Clegg, Geoffrey Will, Theodore Steinberg, Rezwanul Haque https://creativecommons.org/licenses/by/4.0
Performance Improvement of Parabolic Trough Collector With Thermal Oil-Based Metal-Oxide Nanofluids
In this study, the effects of using thermal oil-based nanofluids on the parabolic trough collector (PTC) thermal performance are examined. A methodology is developed to predict the thermophysical properties of several combinations of thermal oils and nanoparticles. Specifically, Syltherm 800 and Therminol VP-1 are selected as they are common heat transfer fluids (HTF) to be combined with Al2O3 and CuO nanoparticles. The nanoparticle dispersion volume fractions (φ) are varied from 0.0% to 3.0% with increments of 0.25%. Additionally, it has been performed a parametric case study for a PTC plant, located in Rome to further emphasize the potential effects of using nanofluids in bulk-scale CST systems. The addition of nanoparticles to thermal oils used as HTFs in PTC systems results in a non-linear increase in both dynamic viscosity and thermal conductivity, leading to increased pumping power requirements and a moderate increase in thermal performance. The capacity factor and annual thermal energy are improved within the margins of 1.5% and 4%, respectively; however, these gains were offset by a significant rise in electricity consumption, especially for Therminol VP-1 based nanofluids due to plateau in thermal conductivity and nonlinear rise in dynamic viscosity against increasing volume fraction of nanoparticles. Unlike Therminol VP-1, the addition of nanoparticles has led to enhance the thermophysical properties of Syltherm 800 in the operational temperature range which led to an increase the annual thermal energy and capacity factor experiencing nonlinear increases in both thermal conductivity and dynamic viscosity.
Copyright (c) 2025 Levent Güner, Onur Taylan , A. Alperen Günay https://creativecommons.org/licenses/by/4.0
Optimizing Solar Thermal and Electrical Output Through a Hybrid Fresnel Lens and TEG System
This study demonstrates the successful integration of a Fresnel lens into a hybrid solar cooking and thermoelectric generation system, providing both thermal energy for cooking and electrical power generation. The study analyzed various tank designs to enhance heat transfer, improve heat distribution, and optimize the cooking surface. The best-performing design, featuring an aluminium heat sink with fins, achieved the highest fluid temperature of 54.44°C, with superior heat transfer efficiency and uniform distribution. Other designs using stainless steel and copper showed promise but faced challenges, such as uneven heat spread and inefficient baffle configurations. The findings underscore the critical role of material selection and design optimization in enhancing the thermal performance of hybrid solar systems.
Copyright (c) 2025 Khalifa Aliyu Ibrahim, Zaharaddeen Ali Hussaini, Fergus Crawley, Mounia Karim, Zhenhua Luo, Abdullah Ayed Alrwili, Christopher Sansom, Jonathan Siviter https://creativecommons.org/licenses/by/4.0
Techno-Economic Optimization of Falling Particle Receivers for Solar Tower Plants
Solid particle receivers are proposed as the next generation of receivers for solar tower CSP plants as they are able to overcome the temperature limits of solar salts. However, maximizing their performance requires robust design optimization tools. Therefore, this study proposes a methodology for the techno-economic optimization of the design of falling particle receivers for polar-field solar tower CSP plants. Given a specific solar field and location, the optimized design is derived using a parametric approach based on Levelized Cost of Electricity (LCOE) minimization, varying the height and the width of the receiver, as well as, the size of thermal energy storage. Methodology is applied to a 100 MWth solar tower plant in Daggett, California, and the results show that the receiver sized using the proposed approach can achieve LCOE of 80.1 $/MWh that is by 2.2 % lower compared to the LCOE of the receiver sized only through on-design performance maximization.
Copyright (c) 2025 Filip Sobic, Giancarlo Gentile, Marco Binotti, Andrea Giostri, Giampaolo Manzolini https://creativecommons.org/licenses/by/4.0
Increasing the Collaboration on Thermal Energy Storage Systems in SolarPACES TCP
This paper presents, mainly, the just recently launched collaboration topics in the Thermal Energy Storage Working Group (TES WG) of the SolarPACES task III. These topics are four: one dealing with the main issues related to molten salt loops, like for example, with the reliability of equipment and instrumentation used in this type of hydraulic loops; another in relation to TES tanks issues, like for example, the identification of failures at high temperature and solutions to implement in the tank design; another focussed on corrosion issues of structural materials used in molten salt loops and on how different coatings can be used for that, and finally another topic focussed on the used of TES not only by storing energy of a CST plant but of other non-dispatchable renewables, like PV or wind, in a Carnot battery.
Copyright (c) 2025 Esther Rojas Bravo, Rocío Bayón, Darío Alfani, Chuncheng Zang, Camila Barreneche, Ángel G. Fernández, Francisco J. Pérez-Trujillo https://creativecommons.org/licenses/by/4.0
TES Model for Hybrid Energy System Analysis
Long-duration energy storage (LDES) is essential for efficiently harnessing renewable energy. While electrochemical energy storage technologies have been increasingly deployed, they often face challenges due to high costs and limited mineral resources. Thermal Energy Storage (TES) offers a promising, cost-effective, and location-independent solution for LDES by storing energy as heat in inexpensive materials. A dynamic TES simulation tool within Flownex was developed to predict the TES outlet temperature for varying inlet conditions within a typical combined heat and power (CHP) system. The application of the dynamic TES model was demonstrated by successfully simulating the transient behaviour of a gas turbine cogeneration system for a 950°C gas turbine inlet temperature and ~18h TES energy storage duration. The model was used to evaluate the economic viability of a TES gas turbine cogeneration system compared to a lithium-ion (Li-ion) battery system for delivering the same output. An economic comparison over a 30-year project lifespan highlights the advantages of TES for LDES.
Copyright (c) 2025 Frikkie Botha, Willem le Roux https://creativecommons.org/licenses/by/4.0
Progress and Prospects of TES for Central Receiver-Based CSP Plants
This review categorizes the thermal energy storage (TES) technologies—sensible heat, latent heat, and thermochemical storage—and evaluates their development, application, and performance within central receiver-based concentrated solar power plants. This study explores the progression of TES systems, delineating the evolution from technologies such as saturated steam and molten salt, first used in the Eurelios power plant in 1980 as a protective storage solution for 30 minutes, to commercial molten salt storage capacities of up to 15 hours. This study also examines emerging research and development technologies aimed at achieving higher efficiencies and operating temperatures. The objective is to identify technological trends, assess the efficacy of different TES systems, and highlight future directions for research and application.
Copyright (c) 2025 Brenda Hernandez Corona, Matteo Chiesa, Nicolas Lopez Ferber, Ahmad Mayyas, Nicolas Calvet https://creativecommons.org/licenses/by/4.0
Characterization of a Novel Coating Process to Darken Sand Particles
The use of solid particles in Concentrated Solar Power (CSP) plants can enhance energy conversion efficiency by elevating the working temperature. For this reason, many researchers are exploring various materials such as silica sand and SiC, among others, and methods to enhance the optical properties while cost is reduced. In this context, this study proposes a novel fabrication method based on the Mn2+ diffusion to darken silica sand particles and, therefore, enhancing their absorptivity. Colorimetry analysis reveals that the obtained particles color closely resembles that of the reference material SiC, while morphology analysis, Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD) confirm an effective fabrication method.
Copyright (c) 2025 Leonel Mario Cerutti Cristaldo, Minerva Díaz Heras, Juan Carlos Pérez Flores, Jesús Canales Vázquez, José Antonio Almendros Ibáñez https://creativecommons.org/licenses/by/4.0
A Simplified Numerical Model to Study the Thermal Behavior of a Cascade LHTES System
To promote the integration of Solar Heat for Industrial processes (SHIP), through the development of innovative cascade Latent Heat Thermal Energy Storage (LHTES) systems, a simplified zero-dimensional model for “shell&tube” LHTES systems that is fast, flexible and sufficiently accurate was set up. This model, programmed in Fortran 90, was developed not only to predict the thermal behavior of a cascade LHTES but also to be usable within a software to evaluate its integration in any plant, including a Concentrated Solar Thermal (CST). The model was validated through a comparison both with a more sophisticated numerical simulation and the experimental results. Finally, the simplified model was applied to a case study to analyse the thermal behavior of a system of three LHTES connected in series
Copyright (c) 2025 Daniele Nicolini, Adio Miliozzi https://creativecommons.org/licenses/by/4.0
Design Features and Material Selection Methodology of High-Temperature Particle-Based Thermal Energy Storage Bin
This study investigates the thermal performance of a proposed design for a particle-based thermal energy storage (PBTES) system. A small-scale TES bin was constructed using masonry materials and a multi-layered structure. The primary objectives were to quantify heat loss through the bin’s wall and to evaluate the thermal conductivity of the insulating material, calcium silicate (CS), at elevated temperatures. Heat transfer rates were measured and calculated using two methods, yielding a minimal discrepancy of 3% between the results. The thermal conductivity of the CS was determined to be 0.115 W/m·K, indicating its effectiveness as a thermal barrier. Additionally, the expansion joint (EJ) layer demonstrated the ability to recover its original thickness after cooling, confirming its utility in relieving stresses resulting from the thermal expansion of the inner layers. These findings support the scalability and efficiency of the proposed PBTES system design.
Copyright (c) 2025 Nader Saleh, Shaker Alaqel, Rageh Saeed, Eldwin Djajadiwinata, Hany Al-Ansary, Abdelrahman El-Leathy, Syed Danish, Zeyad Al-Suhaibani, Sheldon Jeter https://creativecommons.org/licenses/by/4.0
Real-Time Image Enhanced Data-Driven Digital Twin (Real-TImE 3DT) for Flux Density Measurements
Concentrated solar power (CSP) plants are considered one of the most attractive renewable energy producers (used for green fuel and electric power). Consequently, it is essential to enhance the different elements of their power cycles, especially the central receiver and the heliostat field. To achieve this, flux density measurement (FDM) is highly recommended. In this work, a novel methodology for FDM is presented, based on the usage of real-time data-driven simulation models in parallel with the traditional camera methods for the real-time enhancement of the results. In order to improve the output, a graph neural network is used, giving as a result a Real-Time Image-Enhanced Data-Driven Digital Twin (Real-TImE 3DT). All the data are obtained from a pre-existing data platform, where the signals from the sensors of the power plant are logged and stored. This way, it is possible to operate the model manually, or to let it work automatically with these sensors' outputs. Latencies smaller than 10 seconds are achieved and the results from the digital twin showed coherence, easy handling and great inter-operability with the neural network enhancement. On the AI-enhancement’s side, the suppression of up-to 80% of the inaccuracies can be expected under parametrically semi-controlled conditions. Further work is being performed in Solar Tower Jülich (STJ) in order to contrast these results against real experimental measurements.
Copyright (c) 2025 Sergio Díaz Alonso, Christian Raeder, Kai Wieghardt, Bernhard Hoffschmidt https://creativecommons.org/licenses/by/4.0
Optimization of Hybrid Renewable Energy System Incorporating Heliostats with Thermal Energy Storage, PV and Battery Storage for Enhanced Energy Flexibility and Reliability
The urgent need for sustainable energy solutions to combat climate change and the growing global energy demand has stimulated the development of renewable energy technologies. Among these, hybrid renewable energy systems (HRES) that combine multiple energy sources promise enhanced efficiency, reliability and flexibility compared to single-source systems. This research focuses on a novel HRES configuration that integrates a concentrated solar power named solar tower with thermal energy storage (TES), photovoltaic modules and battery energy storage systems (BESS) in North Togo. The study aimed to maximize the energy produced, while reducing costs and finally evaluated the environmental aspect saved. We use parametric optimization through SAM to determine the optimum levelized cost of energy and net present value. SAM software was used for heliostat modelling. The single-owner model was used for financial analysis. The results demonstrated the project's financial viability and environmental impact, with an LCOE of $0.14kWh-1 indicating a competitive cost of energy production and an IRR of 14.87% showcasing strong investment returns. A high NPV of $9,307,001 indicated some good interest in the proposed HRES. Furthermore, the significant reduction of 25,815.7513 tons of CO2 emissions highlights the project's substantial contribution to sustainability and carbon footprint reduction.
Copyright (c) 2025 Maklewa Agoundedemba, Chang Ki Kim, Hyun-Goo Kim, Raphael Nyenge, Nicholas Musila https://creativecommons.org/licenses/by/4.0
High Concentration Optical System for Solar Fuel Production via Cerium Oxide Thermochemical Cycle
The integration of solar energy into hydrogen fuel production marks a key step towards sustainable energy. This study, which is part of a Marie Skłodowska-Curie Action called “TOPCSP”, aims to optimize the design of a concentrated solar power system tailored for high-temperature applications such as thermochemical cycles for hydrogen production. The system features a point-focus tower with compound parabolic concentrators as secondary concentrator to maximize solar radiation capture and to minimize receiver thermal losses, enhancing the efficiency of the solar-to-fuel conversion. Hydrogen is produced through a two-step thermochemical cycle using non-stoichiometric ceria, designed for high efficiency and scalability. Through theoretical modeling and simulations, this work presents an optimal optical configuration that boosts hydrogen production rates and reduces overall system costs.
Copyright (c) 2025 Alejandro González Silvestre, Gioele di Marcoberardino, Marco Binotti https://creativecommons.org/licenses/by/4.0
Modeling of an High-Concentration Solar Reactor for Dry Methane Reforming
Direct solar-powered reforming of methane has the potential to lower the CO2 footprint of reforming and to harvest solar energy with high-efficiency [1]. Combined with bio-sourced feedstock and recycled CO2 to perform dry methane reforming (DMR), this approach can highly decrease methane reforming environmental impact [2]. Using high solar concentration solar towers or parabolic dishes to provide the highly endothermal reaction heat required for DMR, it is possible to reach the temperatures of conventional reformers, ranging from 800°C up to 900°C. At this temperature, radiation losses are such that high solar concentrations approaching 1000x are required to reach high thermal efficiency, making heat flux management highly challenging. Previous work from Université de Sherbrooke experimentally shown the potential for such reactors to operate under high heat flux [3],[4]. The current work presents the modeling approach used to design these reactors and increase the heat flux within the absorption surface, while maintaining reasonable temperature drop within the reactor. Dimensional analysis if first assess that no diffusion limitation occurs within the reactor and the system can be simulated as a plug flow reactor with porous catalyst. Using DMR and RWGS kinetics from literature with 2D modeling in COMSOL Multiphysics, temperature and reaction rates along the reactor are evaluated showing consistency with experimental values. Parametrical analysis shows that optimal catalyst channels width appears to be equal or under 0.5 mm. Finally, it is demonstrated that optimal conversion occurs when around 1/3 of the catalytic bed is covered with metallic conductive fins. Over this value, increased conductivity gains are overpassed by the lowering of catalyst volume within the conduction chamber.
Copyright (c) 2025 Jean-Francois, Emeric Désilets, Nicolas Brissette, Nadi Braidy, Luc Frechette, Mathieu Picard https://creativecommons.org/licenses/by/4.0
Volumetric Absorption of Direct and Indirect Radiation in Porous Redox Structures for Solar Fuel Production
In order to reduce the dependency on fossil fuels and thereby the emission of greenhouse gases, the large-scale production of renewable chemical energy carriers plays an important role. Here, the production of green hydrogen via solar thermochemical redox cycles presents a promising pathway. In order to develop and improve reactor concepts that utilize this approach, the usage of numerical models is essential. The volumetric radiation absorption within porous redox structures is often simplified or neglected within such models. Furthermore, the setup of redox structure and radiation source is often limited to the direct collimated irradiation of flat structures. Therefore, a Monte-Carlo ray-tracing model is developed to simulate the volumetric radiation absorption within porous redox structures of different geometries and reactor boundary conditions. In addition to the direct irradiation of a flat geometry with collimated solar radiation, the indirect diffuse irradiation of a cylindrical redox structure is evaluated. The model setup and resulting absorption profiles are presented here and will serve as an input to material models for heat transfer simulations.
Copyright (c) 2025 Louis Thomas, Stefan Brendelberger, Robin Tim Broeske, Martin Roeb, Christian Sattler https://creativecommons.org/licenses/by/4.0
Maintenance Optimization of Parabolic Trough Power Plants Through a Lifetime Simulation Model Validated With Five-Years of Operational Data
Modelling and Simulation of Concentrated Solar Power (CSP) plants is a crucial requirement for future growth and improvement of the technology. In this paper, the development of a functional and reliable model of a Parabolic Trough Collector (PTC) power plant is presented and validated with existing five-year operational data of a 50 MWel plant equipped with seven hours full load thermal storage, located in Spain. A mean absolute error of 2.53% between the simulation and plant data was found when considering net energy generated over the five-year period. Subsequently, an optimized maintenance plan is proposed, and the plant behavior is forecasted. The new maintenance strategy is developed to optimize the mirrors current cleaning schedule, thereby mitigating significant detrimental soiling effects on the optical efficiency while reducing water and fuel consumption. Results show an increase in solar gain by 0.46% and reductions in water usage and fuel consumption by 22.1% and 22.3%, respectively.
Copyright (c) 2025 Sayra Gomez Garcia, Shahab Rohani, Nicholas Chandler, Peter Schöttl, Thomas Kraft, Gregor Bern https://creativecommons.org/licenses/by/4.0
Preface: SolarPACES 2024, 30th International Con-ference on Concentrating Solar Power, Thermal, and Chemical Energy Systems
Renewable energy technologies are a key element in the journey towards sustainable and secure energy systems. They not only help us neutralize our carbon footprint, but also enable us to harness energy sources that are abundant and more evenly distributed globally. In 2023, the participants in COP 28 committed to triple the installed capacity of renewable power by 2030. Also, the International Energy Agency reports that the annual renewable capacity additions marked a step change in 2023 and are expected to steadily increase over the next years. This huge expansion will be led by market-mature technologies like solar PV and on-shore wind, which are expected to make up each year for nearly 95 % of the renewable electricity capacity additions, until 2030. However, as the penetration of renewables approaches 100%, the availability of clean technologies that allow dispatchable production will no longer be an option, but a necessary element for our energy systems to be not only sustainable, but also flexible and resilient. Also, it has now become very clear that full electrification of our energy uses will not be possible in the short term. The “hard-to-abate” sectors, like energy intensive industries and heavy transport, will require alternative approaches to be decarbonized. Today, industry makes up for roughly 30 % of the total world’s energy consumption and industrial processes require 70 % of their energy input as low-, medium- and, mostly, high-temperature heat. Fulfilling this energy demand in a sustainable way is a challenge that will require the use of multiple energy technologies and vectors. This includes hydrogen and other renewable fuels, but also technologies that can directly produce renewable heat. Concentrating solar thermal (CST) technologies possess all the key features to address these challenges. They can be used to produce (or co-produce) high-temperature heat, electricity, hydrogen and other renewable fuels. They can rely on commercially proven long-duration thermal energy storage solutions, which are not based on critical materials and allow flexible and, potentially, round-the-clock operation. Furthermore, they can support the penetration of non-programmable renewables by providing flexibility and ancillary services to the grid. Several challenges still hinder the deployment of CST technologies. Improving the cost-efficiency is among the first priorities. Research and innovation can partly contribute to this aim, but ensuring a stable pipeline of commercial projects is crucial. In turn, in many markets, today this requires well-designed and stable support policies. From October 7th to 11th, 2024, more than 520 experts and delegates from 41 countries gathered at the Auditorium della Tecnica in Rome (Italy), to attend the 30th edition of the SolarPACES Conference. With 42 years of activity since its inauguration in 1982, the conference has become the world’s reference event for the CST community, which now every year provides an excellent forum for research, industry and policy makers to connect, exchange ideas, build networks, showcase cutting edge innovations, and lay the groundwork for new projects. The Conference boasted a very rich technical program with 4 plenary sessions including 8 keynote presentations and a roundtable discussion, 40 technical sessions with more than 220 talks, 244 posters and a technical visit to ENEA Casaccia Research Center, which hosts the most relevant CST-related research infrastructures in Italy. The participants were greeted during the opening session by the Italian Minister of Environment and Energy Security Gilberto Pichetto Fratin, who pointed out how CST is among the key energy technologies identified by the European Union to achieve its ambitious climate goal of carbon neutrality by 2050 and, accordingly, is expected to contribute to the Italian energy mix in the near future as reported in the National Energy and Climate Plan. This volume collects the 177 full papers submitted for the Conference Proceedings. The papers cover all the 16 conference topics that address a wide and exhaustive range of current issues in the field of CST technologies, from the assessment of solar resource, to the deployment of commercial projects. Almost half of the papers focus on one of three key topics, namely “Analysis and Simulation of CSP and Hybridized Systems”, “Thermal Energy Storage Materials, Media, and Systems”, and “Solar Industrial Process Heat and Thermal Desalination”. This clearly reflects the main trajectories that the CST community has been following in recent years towards the future of the technology. The following papers mark another step to improve the technological and economic performance of CST technologies and foster their further deployment. To the authors of these papers, to those who helped in the organization of the Conference, and to all the participants goes my deepest gratitude.
Copyright (c) 2025 Luca Turchetti https://creativecommons.org/licenses/by/4.0
A concept for the automated installation of heliostats for solar tower power plants was developed with the primary objective of reducing installation costs. Following a discussion on the various types of foundations available for installation, the pile foundation was selected on account of its favourable cost per heliostat. The feasibility of this approach was assessed by calculating the wind loads and the structural stability. Vibratory pile driving was selected as the method for driving the pylons into the ground, as it enables the pile driving of very thin-walled pylons with minimal stress on the component. The installation of a heliostat is a two-step process, involving the piling of the pylons and the subsequent fastening of the concentrator with the tracking device. The fastening is facilitated by thin sheet metal screws, which were determined to be the optimal joining method, considering the requirements. In order to facilitate the efficient transportation of the components and the subsequent installation of several thousand heliostats on the solar field, various installation and material flow concepts were developed and evaluated, with particular attention to the resulting installation cost. Consequently, vehicle concepts for the automatic execution of the two process steps and for the material transport were derived and a design proposal is presented: The first is a heavy tracked vehicle for the purpose of pylon piling, and the second is two smaller vehicles for transporting and assembling the concentrators, with tracking devices.
Copyright (c) 2025 Lars Grobelny, Andreas Pfahl https://creativecommons.org/licenses/by/4.0