Decision-Making and Selection Framework for Potential Implementation of Concentrated Solar Power Technologies: Case Study

Abstract

The decarbonization of industrial processes requires efficient and scalable renewable energy solutions. Concentrated Solar Power (CSP) technology stands out by providing both electricity and high-temperature heat, yet its optimal deployment remains a challenge. This study presents an innovative framework for selecting and optimizing CSP technologies tailored for potential industrial practical applications. In this study, a multi-phase approach is deployed integrating a decision matrix, performance simulations using SOLARPILOT and SAM, and techno-economic evaluation to identify the best CSP solution. The study addresses the feasibility of four candidate CSP technologies, the characteristics of deployment areas, operation parameters such as energy storage time, and characteristics of energy storage material (comparing commercially available materials and an innovative molten salt named FERT-1). The results highlight solar towers as the most suitable technology, while the characteristics of the deployment can lead to over 3.2% difference in annual energy generation (when comparing between two areas, A1 and A2). Regarding energy storage, an optimal storage time of 11 h was identified, achieving a Levelized Cost of Electricity (LCOE) of 24–25 cents/kWh and a 31–32% energy capacity factor. Moreover, regarding energy storage material, the innovative molten salt highlighted improved thermal efficiency.

1. Introduction

The urgent need to decarbonize industrial processes while maintaining reliable energy supply has sparked renewed interest in Concentrated Solar Power (CSP) technologies [1]. Unlike photovoltaic systems, prone to major side effects during their development [2], CSP not only offers the unique advantage of providing electrical power but also high-temperature process heat, making it particularly attractive for industrial applications [3]. The European Union (EU) has committed to achieving net-zero emissions by 2050, driving significant policy and investment efforts toward renewable energy deployment. CSP plays a pivotal role in this transition, particularly in Southern European countries, where high levels of Direct Normal Irradiance (DNI) favor its efficiency. In Spain, for instance, the Escombreras Valley, the focus of this study, exhibits an annual DNI of approximately 2000 kWh/m² with over 300 sunny days per year, making it an ideal candidate for CSP deployment annually [4].

Concentrated Solar Power (CSP) technologies harness solar energy by using optical systems to focus sunlight onto a receiver, where it is converted into heat for power generation. CSP systems are categorized into two configurations, i.e., line-focusing and point-focusing (Figure 1), based on their solar concentration and tracking mechanisms [5]. Line-focusing systems, including Parabolic Trough Collectors (PTCs) and Linear Fresnel Reflectors (LFRs), use single-axis tracking to concentrate sunlight onto a linear receiver. In contrast, point-focusing systems, such as Solar Power Towers (SPTs) and Parabolic Dish Collectors (PDCs), employ dual-axis tracking, directing sunlight to a single focal point, achieving higher operating temperatures and efficiencies [6,7,8].

Among these, SPTs utilize heliostats to reflect sunlight onto a central receiver, where molten salt or another heat transfer fluid absorbs and stores energy at temperatures up to 565 °C [5]. PTCs, the most widely deployed CSP technology, use parabolic reflectors to focus sunlight onto a receiver tube, heating a synthetic oil-based HTF to 400 °C [9]. LFRs offer a cost-effective alternative with flat mirrors directing sunlight to an elevated receiver, enabling direct steam generation but with lower optical efficiency [10]. PDCs, although they are the most efficient CSP technology, remain less commercially viable due to high costs and complex tracking requirements. However, each CSP configuration offers unique advantages, with ongoing advancements focusing on enhancing thermal efficiency, optimizing energy storage, and reducing system costs.

While these technologies continue to evolve with ongoing developments in materials, components, and system configurations aimed at improving efficiency and reducing costs, CSP technology has seen a significant increase in research output [11], shaping the state of the art (Figure 2). To assess this progress, a bibliometric analysis was conducted using Scopus data [12], applying the query TITLE-ABS-KEY (“Concentrated Solar Power”) while excluding publications from 2025 {Query; TITLE-ABS-KEY (“Concentrated solar power”) AND (EXCLUDE (PUBYEAR, 2025))}. The bibliometric analysis reveals a strong and growing interest in CSP (with 1296 documents from all time until the end of 2024), with annual publications exceeding 100 documents since 2018. Furthermore, CSP research spans multiple disciplines, with the highest contributions from energy (32%), engineering (21%), and materials science (10%), highlighting its interdisciplinary nature.

The bibliometric analysis was followed by a keyword analysis carried out following the methodology developed by Mselle et al. [13], using VosViewer version 1.6.19 software [14], creating a network map of the most often occurring keywords (Figure 3). From the documents, a total of 23,778, keywords (author keywords and indexed keywords) were found, and those appearing more than 150 were plotted (76 on the map). The network map visually represents key research themes, interconnections between concepts, and emerging trends in CSP. The bibliometric analysis of CSP research, based on Scopus data, reveals a structured research landscape with key thematic clusters. At the core of this network, solar energy serves as the central concept, demonstrating its fundamental role in the scientific discourse. Several interconnected domains emerge (in clusters highlighted in four different colors), encompassing solar power generation, energy efficiency, heat storage, and advanced power cycles. The distribution of these topics highlights CSP’s interdisciplinary nature, integrating thermodynamics, material science, and renewable energy economics.

One of the primary research clusters (red cluster) focuses on solar power generation and renewable energy systems, indicating CSP’s role in the broader energy transition. Within this domain, significant emphasis is placed on photovoltaics, wind power, fossil fuels, and investment-related challenges [15,16], reflecting ongoing discussions on CSP’s economic viability and competitive positioning against other renewable technologies. The integration of CSP into hybrid energy systems and its cost-effectiveness compared to conventional power sources are prominent topics [17,18], suggesting an increasing focus on optimizing CSP deployment in real-world applications.

Another critical research avenue (green cluster) pertains to heat storage and thermal management, which is essential for enhancing CSP performance and grid reliability. This cluster includes thermal energy storage [19], phase-change materials [20,21,22], molten salts [5,23], and heat transfer mechanisms, all of which are pivotal for extending energy availability beyond sunlight hours. The presence of specific heat, packed beds [24,25], and high-temperature applications suggests active research in optimizing storage materials and improving thermal efficiency. Additionally, power cycle optimization is a key research focus, with studies exploring the Rankine cycle, Brayton cycle, and carbon dioxide-based cycles to enhance the overall efficiency of CSP plants [26,27]. Advanced modeling approaches, such as computational fluid dynamics and heat exchanger performance analysis, indicate a growing interest in improving heat transfer efficiency within CSP systems [28,29,30].

Finally, optical and solar concentration technologies (blue cluster) form another significant research domain, with studies focusing on solar collectors, solar absorbers, parabolic troughs, and solar radiation concentration techniques [28,31,32]. Efforts to enhance solar capture efficiency are reflected in studies related to reflection, optical performance, and concentration processes. These advancements are crucial for improving CSP’s overall efficiency and reducing energy losses. The bibliometric analysis demonstrates that ongoing research efforts are directed toward enhancing CSP system performance, reducing costs, and integrating advanced thermal storage solutions, paving the way for its broader adoption in global energy markets.

The successful implementation of CSP systems requires a balance of technical, economic, and site-specific factors to ensure optimal performance and cost-effectiveness. Solar CSP performance depends on factors like optical efficiency, thermal losses, and energy conversion. Advances in absorber coatings, heat transfer fluids, and thermal storage have improved efficiency [33]. Optimization techniques further enhance performance under varying conditions [34]. Recent studies provide detailed analyses of CSP heat transfer and efficiency improvements [33], reinforcing its viability for future applications. Recent advancements in CSP technology report improved system efficiency and reduced costs, with installation expenses dropping by up to 40% in recent years [35]. Key innovations in thermal energy storage (TES) systems and heat transfer fluids (HTFs) have enhanced operational flexibility and reliability.

Despite these advancements, CSP faces major deployment challenges, including high capital costs, site-specific performance variations, integration complexity with industrial processes, and economic competition with conventional energy sources. A robust financial evaluation requires the consideration of CAPEX, OPEX, LCOE, system performance metrics, and environmental factors. However, previous studies often focus on generic evaluations, e.g., performance optimization, storage systems, and economic analysis, rather than real-world industrial case studies. These studies lack an in-depth analysis of CSP’s comparative environmental footprint, waste heat management, and the impact of CSP on energy grids, among others. Therefore, it is of huge interest to align CSP research towards this direction, tailoring decision-making frameworks for industrial needs.

This study presents an innovative methodology for CSP selection, design, and economic assessment at the Escombreras Valley industrial complex. Unlike previous studies that focus on general feasibility, this research integrates a multi-criteria decision framework tailored for real-world industrial applications. Key contributions include the following:

• A systematic CSP technology evaluation considering environmental, technical, and economic factors.
• Optimized system design using detailed performance simulations.
• A financial feasibility assessment incorporating LCOE and capacity factor (CF) metrics under different operational scenarios.
• Investigation of molten salt as an innovative HTF to enhance efficiency and storage.
• A novel methodology to optimize storage duration, maximizing dispatchability and cost-effectiveness.

A solar field with heliostats is designed and simulated using SOLARPILOT software version 1.5.2, while the CSP plant performance is modeled in SAM (System Advisor Model) version 2024.12.12 (SSC 298). The selected CSP technology is optimized to generate 1 MW of power at the Escombreras Valley industrial complex. By introducing a storage optimization strategy and exploring advanced HTF solutions, this study provides a novel decision-making framework for CSP deployment in industrial applications, bridging the gap between technological advancements and real-world implementation.

2. Methodology

This section presents a comprehensive techno-economic decision-making framework for selecting the most suitable concentrating solar power (CSP) technology for the Escombreras Valley (Figure 4). The analysis considers four major CSP technologies: parabolic troughs, solar towers, linear Fresnel, and parabolic dishes, evaluating them based on technical, environmental, and economic criteria. The methodology follows a systematic approach, beginning with an assessment of the geographic characteristics of the available areas for CSP installation. This includes an analysis of factors such as land availability, solar irradiance, and climatic conditions.

Subsequently, an economic analysis is conducted to evaluate key financial parameters, including the total installed cost, levelized cost of energy (LCOE), project size, and storage capacity. The primary advantages and disadvantages of each CSP technology are also examined to provide a well-rounded comparison. To facilitate decision-making, a techno-economic decision matrix is applied, assigning scores to each CSP technology based on the previously defined criteria. The technology with the highest overall score is recommended for deployment in the Escombreras Valley. Following technology selection, the methodology proceeds to solar field optimization for the designated installation areas. The optimized design is then used to simulate the performance of the selected CSP technology under site-specific conditions. These simulations incorporate weather data, solar field design parameters, and different heat transfer fluids (HTFs) to assess system efficiency. Finally, comparative analysis of simulation results enables the identification of the most favorable operating conditions, ensuring optimal performance for the selected CSP technology.

2.1. Available Areas in the Escombreas Valley

Figure 5 shows the available areas in the Escombreras Valley where CSP can be installed. The site exhibits characteristic Mediterranean climate patterns with several notable features. The solar resource is exceptional, with Direct Normal Irradiance (DNI) reaching approximately 2000 kWh/m²/year, complemented by more than 300 clear-sky days annually [4,36]. The location benefits from high atmospheric transparency attributed to consistently low cloud cover. The temperature regime follows typical Mediterranean patterns, with a mean annual temperature of approximately 18 °C. Summer periods experience maximum temperatures ranging from 30 to 35 °C, while winter minimums typically remain between 5 and 10 °C, with frosty days occurring infrequently. Precipitation patterns align with Mediterranean characteristics, averaging around 300 mm annually, with predominantly dry conditions throughout the year. The rainfall distribution is notably irregular, following the typical Mediterranean precipitation regime, where most rainfall is concentrated in specific periods rather than being evenly distributed throughout the year.

Area (A1), in yellow, is characterized by its elevated terrain on a hillside. This location benefits from excellent solar exposure due to its elevation and southern orientation, making it a prime spot for capturing sunlight. The terrain is irregular, with varying elevations, which presents challenges for construction and requires careful land preparation. However, the expansive view and openness of the area provide an advantageous setting for solar energy projects. Its distance from industrial infrastructure reduces potential shading and pollution, offering a cleaner environment for solar applications. On the other hand, area (A2) in blue is located on a hillside within a more industrial setting. Its sloped terrain presents unique challenges for development, requiring innovative design solutions to accommodate the uneven ground. Despite these challenges, the site’s proximity to existing industrial facilities could offer logistical advantages, such as easier access to grid connections. The natural elevation may also provide some protection from industrial pollutants. However, potential shading from nearby structures and careful planning to manage the terrain’s irregularities are key considerations for any solar project in this area.

2.2. Technical Features of CSP Technologies

Table 1. Technical features of the CSP technologies [38].

	Parabolic Trough	Tower	Fresnel
Application	Utility-scale generation Daytime generation, extended into the evening in most cases	Utility-scale generation Daytime generation and/or peaking	Utility-scale generation Daytime generation
Advantages	Well proven with 5 gigawatts (GW) in operation	Stable and flexible operation because of extended storage; effective decoupling of the solar field and power block operation	Tight configuration with minimal footprint Simple systems with good local manufacturing potential
	Stable operation under semi-cloudy conditions because of built-in 30–45 min of inertia provided by the heat transfer fluid system	Towers are more efficient and due to higher operating temperatures, have a greater thermal storage capacity per kilogram of molten salt than both parabolic trough and Fresnel CSP	Good for solar augmentation of existing thermal cycles
	Short focal distance allows use in higher-humidity and low-visibility environments	Simpler direct storage configuration	Good for low-cost heat supply
	Can support storage	Flexibility in terms of ground flatness
	Low land use factor
Disadvantages	Poor yield from line-focusing systems in winter months in relatively high latitudes	Long focal distance poses an issue in sites with dust, aerosols, or humidity in the atmosphere	Less efficient than parabolic troughs or towers
	Requires flat sites to deploy the solar field, which means that the ground must sometimes be flattened	Performance can be poor in semi- cloudy conditions because of refocusing protocols	Poor yield from line-focusing systems in winter months at relatively high latitudes
	Environmental risk posed by oil-based heat transfer fluid	Harm to the avian population has been reported High land use factor
	Low plant peak efficiency
	Fire risk caused by heat transfer fluid in the solar field and the pumps
	Steam cycle efficiency is lower due to the 400 °C limit

summarizes the key differences between CSP technologies, presenting advantages and disadvantages and their applications considering some characteristics presented in the SWOT (strengths, weaknesses, opportunities and threats) analysis in the study by Kassem et al. [38].

2.3. Economic Trends in CSP Technologies

According to IRENA [39], most existing systems use linear concentrating systems called Parabolic Trough Collectors (PTCs). Specific PTC configurations must account for solar resources at the location and the technical characteristics of the concentrators and heat transfer fluids. Solar towers (STs) are the most widely deployed point-focus CSP technology but represented only around a fifth of the systems deployed at the end of 2020 [40]. Solar towers achieve very high solar concentration factors (above 1000 suns) and operate at higher temperatures than PTCs. This can give the solar tower systems an advantage, as higher operating temperatures result in greater steam-cycle generating efficiency. Higher receiver temperatures unlock higher power block efficiencies, resulting in greater storage densities within the molten salt tanks, driven by a more considerable temperature difference between the cold and hot storage tanks. Both factors cut generation costs and allow for higher capacity factors [39].

Total Installed Cost

According to the results published in the IRENA report [39] in the early years of CSP plant development, adding thermal energy storage was often uneconomic and generally unwarranted, so its use was limited. Since 2015, however, only some projects have been built or planned without thermal energy storage. Adding this is now a cost-effective way to raise the capacity factors while contributing to a lower LCOE and greater flexibility in dispatch over the day. The average thermal storage capacity for PTC plants in the IRENA Renewable Cost Database increased from 3.3 h between 2010 and 2014 to 6.1 h between 2015 and 2019 (an 84% increase). For STs, that value increased from 5 h in 2010–2014 to 7.7 h in 2015–2019 (a 53% increase) [39]. Figure 6 shows the total installed cost breakdown for the PT and ST. The total cost of the PTC decreased from USD 9593 in 2010 to USD 4449 in 2020, and the ST’s cost abruptly dropped from USD 17,671 to USD 5938, representing a 70% reduction over the total cost. For the PTC plant, the solar field costs decreased from 44% of the total cost in 2010 to 30% in 2020, which represents a reduction of 68%. On the other hand, the total power block cost share increased from 15 in 2010 to 19% in 2020, even though its cost fell by 40% over the period. Thermal energy storage share rose from 9% in 2010 to 15% in 2020. Meanwhile, the contingency costs remained the same, representing 8% of the total cost, and the owner’s cost increased from 5% in 2010 to 9% in 2020. The heat transfer fluid share rose from 9% in 2010 to 11% in 2020. For the ST, heliostat cost decreased from 31% in 2011 to 28% of the total cost in 2019. Over that decade, the reduction in the cost of the heliostat field was significant, with costs falling by 70% between 2011 and 2019, from USD 5528/kW to USD 1652/kW. The cost of the receiver fell by 71% over the 2011 to 2019 period, from USD 2868/kW to USD 819/kW, with the receiver’s share of total costs falling from 16% to 14%, and the balance of plant and engineering (BoP) decreased from 16% in 2011 to only 3% in 2019. On the other hand, the power block share cost increased from 12 in 2011 to 16% in 2019. The share cost of thermal energy storage rose from 9 to 10%; the contingency cost increased from 8 to 14%, and owner’s costs fell by only 12% over the period, with their share of overall costs rising to 14% in 2019.

Figure 7 shows the total cost of the CSP installed by project, size, collector type, and storage amount from 2010 to 2020. The total installed cost for the CSP plant declined during the last decade, even though the size of the project’s thermal energy storage systems increased. The average total installed cost fell by 50% over this period. It is also noted that between 2017 and 2021, the project used predominantly ST technology with a small size of up to 50 MW. Meanwhile, medium-sized projects have used ST and PTC technologies up to 200 MW.

Figure 8 presents the Levelized Cost of Electricity (LCOE) for the CSP project’s size and amount of storage. The line represents the average LCOE for the period of 2010 to 2021. From 2010 to 2012, the global weighted average LCOE by project declined slightly, albeit within a widening range, as new projects came online. This changed in 2013 when a clear downward trend in the LCOE of projects emerged as the market broadened. Rather than technology-learning effects alone driving lower project LCOEs from 2013 onward, the shift in deployment to areas with higher DNIs from 2013 to 2015 also played a role. From 2016 to 2019, costs continued to fall, with projects commissioned in 2018 and beyond achieving estimated LCOEs of between USD 0.08/kWh and USD 0.14/kWh.

Figure 9 presents the O&M costs per kWh for some countries. Compared to solar PV and many onshore wind farms, the CSP O&M cost is more expensive, about 18% to 20% of the LCOE for projects in G20 countries. Taking this into account, the LCOE calculations in the following section reflect O&M costs in the IRENA Renewable Cost Database that declined from a capacity-weighted average of USD 0.037/kWh in 2010 to USD 0.015/kWh in 2020 (a 59% decline). The corresponding 2021 value is USD 0.022/kWh (40% lower than in 2010) [39]. The average cost of solar tower O&M in Spain is cheaper than the parabolic trough.

2.4. Decision Matrix

After a literature review, the main features of parabolic troughs, solar towers, linear Fresnels, and parabolic dishes were identified and are summarized in

Table 2. Decision matrix for CSP technology implementation.

				Parabolic Trough	Score	Solar Tower	Score	Linear Fresnel	Score	Parabolic Dish	Score
Technical	Efficiency	Capacity	MWe	10–200	5	10–150	5	10–200	5	0.01–0.4	1
		Solar efficiency max		20% expected	2	20% demonstrated 35% expected	4	21% demonstrated	2.5	29% demonstrated	3
		Plant peak efficiency	%	14–20	3	23–35	4	~18	2.5	~30	4
		Thermal efficiency	%	30–40	4	30–40	4	-	-	30–40	4
		Ideal conversion efficiency	%	33%	3	45%	4.5	25%	2.5	65%	5
		Collector efficiency	%	63%	3.5	72%	5	36%	2	66%	4
		Stagnation temperature	ºC	600	3	1750	5	300+	2	1200+	5
		Optical efficiency	%	80	4	Varied	3	67	3	94	5
		Concentration ratio	Number *(SUNS)	30–100	2	300–1500	5	70–80	2	500–1500	5
		Capture efficiency	%	91	4	Varied	3	76	3.5	100	5
		Fraction of electrical output	%	10	3	10–20	4	Higher	5	4	1
	Compatibility with working fluid	Pressure tolerance	bar	40–100	4	100+	5	69	3	20	2
		Temperature tolerance	ºC	100–400	3	150–800	5	100–300	2.5	500–1500	5
		Operating temperature of the solar field	ºC	290–550	4	250–650	5	250–390, possibly up to 560 °C	4.5	800	5
		Compatibility of the heat transfer medium		Synthetic oil	3	Molten salt	5	Water	1.5	Air	1.5
	Reliability	Reliability	Prediction	5.5—V. low	2	Medium	3	Medium	3	Med–low	2.5
	Availability	Use of standard technologies or parts		Med–low	2.5	Med–low	2.5	High	3	V. low	1
Economical	Affordability	Capital cost	USD/kW	3972	4	4000	4	5168	3	12.578	1
			USD/m2	424	3	476	3	234	4	–
	Maintenance	Total M&O cost in Spain	USD/kWhe	0.023	3	0.025	3	Low	5	0.20	4
	Maintenance	Total M&O cost	USD/kWhe	0.012–0.02	4	0.034	3	Low	5	0.21	4
	Cost	Levelized Cost of Electricity (LCOE)	USD/KWh	0.26–0.37 (no TES) and 0.22–0.34 (with TES)	4	0.2–0.29 (6–7.5 h TES and 0.17–0.24 (12–15 TES)	4	0.17–0.37 (6 h TES)	4	-
	Cost	Total cost	USD/kWh	4449	4	5938	3	-		-
Environmental	Resource usage	Land usage	m2/MWh/year	3.2	3	4.6	5	1.8	2	4.15	4
		Area requirement	m2/MWh	4–6	4	8–12	2	6–8	3	30–40	1
		Tolerance of slope	degrees	<1	2	Flexible	4	<1	2	Flexible	4
		Water-cooled	m3/MWhe	3.07	3	2.27	4	-		None
		Water mirror washing	m3/m2/year	0.022	4	0.022	4	0.022	4	0.022	4
		Efficiency at different scales		Better	4	Poor	2	Better	4	Better	4
	Scalability	Suitable operating range	MW	0.05–200	4	0.5–200	4	0.05–100	3	0.025–100	3
		TOTAL			101		116		87.5		86

, which is based on the analysis proposed by Nixon et al. [41] and Islan et al. [6]. With this, an analytical matrix decision was provided to evaluate the best choice for the concentrating solar power plant considering the following categories:

• Technical.
• Environmental.
• Economic.

These categories are divided into different criteria. Some of these criteria have parameters highlighted in yellow, which were attributed a score based on the geological characteristics of Escombreras Valley, such as the slope of land, weather, and disposable land; technical features, for example, desired thermal storage capacity and plant efficiency; and cost of operation and maintenance. These scores vary from 1 to 5, where 1 represents the worst, and 5 represents the best feature, as shown in Figure 10. The scores of each parameter for each CSP are summed up, and the CSP that presents the highest score is the most appropriate to be deployed at Escombreras Valley for the CORALIS project.

Table 2 presents each solar thermal technology’s categories, criteria, and scores. The solar tower, which uses a heliostat collector, shows a higher score (116), followed by the parabolic trough with 101, the linear Fresnel with 87.5, and finally, the parabolic dish with 86. In addition, Table 2 summarizes the features of the parabolic trough, solar tower, and linear Fresnel, with their application, advantages, and disadvantages. The scoring criteria are taken based on the following:

• The weightings are established through a combination of expert judgment and empirical data, reflecting the priorities and constraints specific to the Escombreras Valley. This approach ensures that the most relevant factors are prioritized according to their impact on the project’s success.
• Geographic Considerations: Geographic characteristics of the Escombreras Valley, such as land topography, are incorporated into the weighting scheme. This ensures that the decision matrix reflects geographical challenges and opportunities, providing a tailored evaluation for the location.

This scoring system reflects the specific requirements of the Fertiberia facility and the unique characteristics of the Escombreras Valley site, particularly the following:

• The need for efficient power delivery over distance;
• The integration of innovative molten salt technology;
• The adaptation to sloped terrain;
• The optimization of land use and resources.

Other relevant aspects of concentrating solar power presented in the literature can contribute to the final decision of the best choice for the Escombreras Valley. The parabolic trough generally uses thermal oil, although it can work with molten salt. This is due to the problems of the latter’s high viscosity and high melting temperature. In addition, this technology is more suited to deserts and stepped areas. Although the linear Fresnel provides the most efficient land use out of the solar thermal technologies presented, it requires a level ground with a less than one-degree tolerance. On the other hand, the type of terrain for solar tower deployment is variable. While leveled ground is the most common choice, it has been applied on hillsides [42]. Hence, based on this matrix decision, the CSP features presented in Table 1 and Table 2, and the geological characteristics of the Escombreras Valley, we conclude that the solar tower (ST) provides the best features for deployment in Escombreras Valley. It is important to highlight that geographic factors significantly influence the technology rankings within the decision matrix (Figure 11). These factors, including land usage, area requirements, slope tolerance, and water management, are assessed using specific metrics. For example, land usage considers integration with existing infrastructure, favoring technologies like solar towers that can be incorporated into industrial areas. Area requirements evaluate the land needed relative to power output, with more efficient technologies receiving higher scores. Slope tolerance is crucial for varied terrain, benefiting technologies like solar towers and parabolic dishes. Water management assesses both cooling system efficiency and mirror washing needs. These geographic parameters directly impact the scoring and therefore the ranking of each CSP technology.

Figure 12 shows a concentrating solar tower power plant (CSP) scheme. This CSP comprises a heliostat field, tower and receiver, thermal storage, and power cycle. The latter has a turbine, a condenser, and a make-up water tank. Descriptions of each element and the process flow are presented as follows:

1.

Heliostat Field: This array of mirrors, known as heliostats, tracks the sun and reflects its rays onto a central receiver atop a tower. This arrangement maximizes the concentration of solar energy.

2.

Tower and Receiver: At the top of the tower, the receiver captures the concentrated solar energy. This energy is then transferred to a heat transfer fluid (HTF), which circulates through the receiver.

3.

Thermal Storage: The hot fluid is divided into two streams. One part is stored in a hot storage tank. This storage allows the plant to continue operating even when sunlight is not available, offering flexibility and reliability.

4.

Power Cycle: The second stream of hot fluid transfers its energy via a heat exchanger to a power cycle, typically a Rankine cycle, where it heats water to create steam.

5.

Turbine and Condenser: The steam generated drives a turbine, converting thermal energy into mechanical energy, and subsequently into electrical energy via a generator. After passing through the turbine, the steam is condensed back into water in the condenser.

6.

Make-up Water Tank: This component ensures that there is always sufficient water to convert into steam, compensating for any losses.

The orange line represents the cold fluid that is initially pumped to the tower to absorb solar energy. Upon heating, the fluid becomes a hot fluid (red line) and is directed towards either the storage or the power cycle. The blue line depicts the water in the power cycle. This water is pressurized and heated in the heat exchanger, creating steam. The steam drives the turbine, and after energy extraction, it is condensed and either reused or directed to an industrial process. When sunlight is unavailable, the stored hot fluid can still generate steam, maintaining continuous power production. The power plant design considered in this work is based on the System Advisor Model (SAM), which provides a detailed framework for CSP systems. The SAM includes specific configurations optimized for various industrial applications, ensuring that the methodology is tailored to this context. By leveraging the SAM, we ensure the design is representative of real-world CSP plants with integrated industrial processes [43,44].

The solar technology process assessment is presented in Figure 13, which outlines a structured procedure for solar power project development, beginning with a Decision Matrix Analysis to evaluate environmental, technical, and economic criteria. This analysis informs the technology selection phase, where tower technology is identified as the most suitable option. Next, the solar field design stage utilizes the software Solar Pilot version 1.5.2 to design the solar field layout, optimizing for maximum efficiency. This design is then integrated into the System Advisor Model (SAM) to analyze energy production and economic viability. The SAM uses geographic parameters, such as solar irradiance, to provide detailed energy and cost assessments [43,44]. This methodical process ensures thorough evaluation and effective design for optimal solar energy solutions that best suit the Escombreras Valley. It can also be applied to other CSP projects, offering a versatile framework for various solar implementations.

3. Results

As presented in Section 2, the decision matrix developed in this project to analyze which solar technologies best suit the Escombreras Valley, considering the environmental, technical, and economic features, presents the tower technology as the most appropriate for this project.

3.1. Innovative Molten Salt FERT-1

A comparative analysis was conducted between conventional binary molten salt (60% NaNO₃ + 40% KNO₃), widely implemented as a heat transfer fluid in CSP tower applications, and an innovative quaternary salt mixture, FERT-1, developed by Fertiberia. The thermophysical properties were characterized using CALPHAD methodology and validated through differential thermal analysis (DTA) and X-ray diffraction (XRD) analyses. Experimental measurements of density, viscosity, specific heat capacity, and thermal conductivity were performed for both salt mixtures in their liquid phase, as illustrated in Figure 14. The results demonstrate that FERT-1 exhibits an approximately 10% enhancement in heat capacity compared to the conventional binary salt, while maintaining comparable values for other thermophysical properties. The quaternary mixture presents a melting point below 115 °C and demonstrates thermal stability within the range of 110–500 °C, potentially expanding the operational temperature range for concentrated solar applications. This extended range, particularly between 150 and 250 °C, could facilitate increased solar share in CSP systems [45].

3.2. Solar Field

Power tower solar fields comprise multiple heliostats, each directing sunlight onto a central receiver. Since neighboring heliostats often exhibit similar performance, a single heliostat can be used to approximate the behavior of a small group. To ensure precise optical performance calculations, SolarPILOT evaluates each heliostat individually, with accuracy improving as the zone size approaches that of a single heliostat [32]. Using this approach, the solar fields for areas A1 and A2 were designed and optimized, as shown in Figure 15 and detailed in

Table 3. Solar field specification of areas A1 and A2.

Parameters	Solar Field A1	Solar Field A2
Heliostat width [m]	3.75	3.75
Heliostat height [m]	3.75	3.75
Single-heliostat area [m2]	13.64	13.64
Number of heliostats	1111	820
Total heliostat reflective area [m2]	15,127.5	11,144.4
Receiver height [m]	3.23	3.20
Receiver diameter [m]	2.50	2.58
Tower height [m]	29.3	30
Receiver number of panels	20	20

. The primary distinction between the two areas lies in the total reflective area and the number of heliostats. The solar field in area A1 consists of 1111 heliostats, covering a reflective area of 15,127.5 m², while area A2 contains 820 heliostats, with a reflective area of 11,144.4 m².

Hence, the simulation in the SAM is performed. The simulation framework starts by selecting the HTF, a commercial molten salt (60% NaNO₃ and 40% KNO₃), and Fert-1 Salt (Figure 16). For each HTF, simulations are conducted for areas A1 and A2. The results are analyzed for the CSP working with both areas and HTFs. Finally, the results are compared to determine the most suitable HTF and area combination for the specific application. This structured approach allows for a comprehensive evaluation of HTF performance across different geographic and environmental conditions. For comparison, the following parameters are considered:

• Capacity Factor (CF): a measure of how much energy a plant produces compared with its maximum output.
• Levelized Cost of Energy (LCOE): the total project lifecycle cost expressed in cents per kilowatt-hour of electricity that the system delivers over its life to the grid for front-of-meter projects or to the grid and load for behind-the-meter projects.
• Annual Energy: measures the system’s total electricity over a year.
• Thermal Energy Storage (TES) Capacity: total capacity of heat transfer fluid storage.

3.3. Comparison Results Between CSP Installed in Areas A1 and A2 Working with Molten Salt (60% NaNO₃ + 40% KNO₃)

Figure 17 shows how the three key performance indicators of a Concentrated Solar Power plant (Levelized Cost of Electricity (LCOE), capacity factor, and annual energy production) vary with the thermal energy storage (TES) capacity. The analysis compares two scenarios for the CSP installed in areas A1 and A2 for different storage capacities ranging from 5 to 15 h. The LCOE exhibits a declining trend with increased storage capacity, starting at ~28.5 cents/kWh for 5 h ad stabilizing around 24–25 cents/kWh beyond 10 h. A2 consistently achieves a lower LCOE than A1, indicating superior cost-effectiveness. The capacity factor increases from ~26% at 5 h to ~32% at 15 h, though the rate of improvement diminishes after 10 h, suggesting diminishing returns. A2 consistently outperforms A1, confirming its better operational efficiency. The annual energy production follows a similar upward trend, ranging from ~5.5 GWh at 5 h to ~6.5 GWh at 15 h. The performance gap between A1 and A2 remains stable, averaging ~3.2–3.6% higher energy output for A2. From 11 h onward, both the LCOE and capacity factor stabilize, indicating this as the optimal storage duration. The findings confirm A2 as the best choice for CSP deployment, due to its lower LCOE, higher capacity factor, and greater annual energy output.

3.4. Comparison Results Between CSP Installed in Areas A1 and A2 Using Molten Salt FERT-1

The same procedure performed for the CSP working with molten salt (60% NaNO₃ + 40% KNO₃) as the heat transfer fluid is reproduced in this section for the CSP working with the molten salt FERT-1. Figure 18 shows how the Levelized Cost of Electricity (LCOE), capacity factor, and annual energy production vary with thermal energy storage (TES) capacities. The analysis compares results for areas A1 and A2 across storage capacities ranging from 5 to 16 h. The results demonstrate that the LCOE decreases with increasing storage, stabilizing at around 24–25 cents/kWh beyond 8 h, with A1 consistently exhibiting a lower LCOE than A2. This indicates that extending storage improves cost efficiency but with diminishing returns beyond a certain threshold.

The capacity factor increases with TES, reaching approximately 32% for A1 and 31% for A2, where additional storage has minimal impact. Similarly, annual energy production rises with TES, with A1 consistently generating more energy than A2. However, gains become marginal beyond 10 h of storage, suggesting an optimal TES range for balancing cost and performance. These results highlight that increasing TES enhances system efficiency, although economic benefits reach a point of diminishing returns after a critical storage duration, emphasizing the importance of site-specific optimizations.

Table 4. Costs of CSP tower installed in area A2 for 11 h of storage.

Parameters	(60% NaNO3 + 40% KNO3)
BOP (M USD)	0.73
Contingency (M USD)	1.39
Tower (M USD)	4.23
TES (M USD)	1.47
Heater (M USD)	0.63
Power cycle (M USD)	2.61
Heliostats (M USD)	3.97
Site improvement (M USD)	0.5
Receiver (M USD)	5.77
Total direct cost (M USD)	21.31

presents the total direct costs of the CSP tower installed in area A2 working with conventional molten salt (60% NaNO₃ + 40% KNO₃) and 11 h of storage, and Figure 19 shows the costs of each element of the CSP tower regarding the total direct cost. The total direct cost of the CSP in this case is USD 21.31 million (M USD). Regarding the distribution, the receiver is the most capital-intensive component, accounting for 27% (USD 5.77 M) of the total cost, due to its advanced materials and engineering requirements for efficient solar energy absorption and heat transfer. The tower follows at 20% (USD 4.23 M), reflecting the substantial structural investment needed for system support. The heliostat field, responsible for solar tracking, constitutes 19% (USD 3.97 M), making it the third-largest cost component. The power cycle contributes 12% (USD 2.61 M), covering the power-to-heat conversion system. TES and contingency each represent 7% (USD 1.47 M and USD 1.39 M, respectively). The heater (3%, USD 0.63 M) and BOP (3%, USD 0.73 M) have minor cost shares, while site improvement is the least expensive at 2% (USD 0.50 M), indicating minimal land preparation costs. Notably, 66% of the total system cost is concentrated in the receiver, tower, and heliostats, highlighting these as key areas for potential cost reductions. In contrast, TES and power cycle costs, though essential, have relatively lower shares, suggesting a limited immediate impact on total system cost through their optimization.

4. Conclusions

This study introduces a comprehensive and practical framework for the selection, optimization, and evaluation of Concentrated Solar Power (CSP) technologies for industrial applications, addressing the growing need for scalable and efficient renewable energy solutions in the context of industrial decarbonization. By integrating a multi-criteria decision matrix, performance simulations using SOLARPILOT and SAM, and a detailed techno-economic analysis, the methodology offers a robust, data-driven approach to identify the most suitable CSP configurations. Among the four CSP technologies assessed, the solar power tower emerged as the optimal solution, demonstrating superior performance based on the technical, environmental, and economic criteria.

Site-specific analysis further revealed that deployment area characteristics significantly influence energy output, with area A2 outperforming area A1 by 3.2–3.8% in annual energy production. Additionally, an optimal thermal energy storage duration of 11 h was identified, balancing energy dispatchability and cost efficiency. The system achieved a Levelized Cost of Electricity (LCOE) of 24–25 cents/kWh and a capacity factor of 31–32%, underscoring its competitiveness for industrial use.

In terms of thermal energy storage materials, this study compared conventional solar salt with the innovative FERT-1 molten salt. While solar salt remains a strong baseline due to its high operating temperature and cost-effectiveness, FERT-1 demonstrated a 10% increase in heat capacity and a broader thermal stability range (110–500 °C), offering enhanced thermal efficiency and operational flexibility.

Overall, this framework not only supports evidence-based decision-making for CSP deployment but also offers a flexible and accessible methodology using open-source tools. It enables tailored system design based on site and performance requirements, making it highly applicable to a wide range of industrial energy scenarios. The findings contribute to the advancement of CSP technologies as a viable, scalable, and sustainable solution for industrial decarbonization efforts.