Following the successful completion of yet another project, FersiSolar once again demonstrates what consistent solar field expertise looks like when applied to real operating conditions – translated into delivered results. 

Project Context and Scope of Services 

The project addressed a familiar but critical challenge in large solar thermal plants: the gap between expected performance under theoretical design conditions and actual performance under real‑world operation. While the plant was engineered to meet specific output and efficiency targets, observed behavior over time revealed deviations driven by operational constraints, component performance variability, and system‑level interactions within the solar field. 

To address these challenges, FersiSolar was engaged to deliver a comprehensive and integrated set of services, including: 

• Advanced plant and solar field performance analysis based on operational data 

• Root Cause Analysis (RCA) of low‑performing collectors, using tracking, optical, and thermal performance assessment 

• Continuous remote monitoring of solar field performance, including early detection of abnormal behavior and timely notification protocols 

• Targeted recommendations to improve temperature control, flow management, and solar field balancing 

• Multidisciplinary solar field engineering support across mechanical, process, I&C, electrical, and civil disciplines 

• On‑site engineering support during construction activities and throughout commissioning 

These services were delivered as a single, coordinated effort, ensuring technical consistency from diagnosis through implementation and enabling the plant to progressively close the gap between theoretical expectations and achieved operational performance. 

From the outset, the collaboration focused on establishing a clear, data‑driven understanding of plant behavior and operational constraints under real conditions. The engagement was addressed as a cohesive, end‑to‑end effort, integrating analysis, operational support, and on‑site engineering activities. 

The strength of this foundation was clearly recognized by the customer: 

“FersiSolar demonstrated strong expertise in optimizing plant operation, identifying concrete performance improvement opportunities through detailed plant data analysis.” 

This analytical depth formed the backbone of all activities delivered throughout the project. 

Identifying the Real Sources of Underperformance 

A key pillar of the project was the precise identification of performance limitations within the solar field. A structured diagnostic process was applied to investigate performance deviations at collector level, supported by detailed operational data and field measurements. 

Rather than focusing on isolated symptoms, this structured approach enabled a clear understanding of underlying causes, interactions between subsystems, and recurring patterns affecting performance. As a result, corrective actions could be prioritized based on impact and operational relevance, rather than applied generically across the field. 

The customer emphasized the value of this approach, noting that:

“FersiSolar showed deep experience in the Root Cause Analysis of low‑performance collectors by combining tracking data with optical and thermal performance assessment, enabling rapid identification of underperforming collectors and timely, effective corrective actions.” 

This methodology allowed inefficiencies to be isolated with accuracy, ensuring responses were targeted, actionable, and firmly grounded in measurable plant data, with a direct impact on long‑term emissions reduction and performance stability. 

Driving Measurable Solar Field Performance Improvements 

Building on this analytical foundation, FersiSolar delivered clear and actionable recommendations aimed at improving overall solar field performance. Particular attention was given to critical operational parameters such as temperature control and solar field balancing, ensuring stable operation and optimized energy delivery to the power block. 

These recommendations were developed with a strong operational mindset, aligning detailed engineering insight with practical, day‑to‑day plant implementation. Emphasis was placed not only on achievable performance gains, but also on ensuring that proposed actions could be sustained under variable operating conditions and evolving plant constraints. 

 Continuous Oversight Through Remote Monitoring 

To safeguard performance gains and support operational stability, routine support was delivered through continuous remote monitoring of the plant’s performance. 

Remote monitoring was used as a permanent operational support tool, providing continuous visibility of solar field behavior over time. This approach supported early detection of deviations, reduced response times, and enabled informed operational decision‑making during transient conditions, maintenance periods, and off‑design operation. 

The importance of this capability was clearly acknowledged by the customer, who described that:

“The service provided by FersiSolar includes routine support through remote monitoring of the plant’s performance, with immediate notification protocols for any abnormal behavior detected within the solar field.” 

Comprehensive Solar Field Engineering Support 

The project also involved extensive solar field engineering support across mechanical, process, I&C, electrical, and civil disciplines. This included advanced analysis of the existing solar field and its hydraulic limitations, ensuring system‑wide impacts were fully understood prior to implementation. 

In parallel, FersiSolar supported on‑site inspections during construction activities and provided technical assistance throughout commissioning, maintaining alignment between design intent, installation quality, and operational readiness. The breadth of activities was handled as a unified scope, strengthening overall industrial competitiveness. 

A Structured, Long‑Term Technical Partnership 

This project collaboration was not limited to isolated studies or one‑off interventions, but rather evolved into a structured, ongoing technical engagement extending over operational periods. Analysis, monitoring, and engineering support were applied iteratively, allowing findings from one phase to be validated, refined, and extended in subsequent operating windows. 

Throughout the engagement, FersiSolar worked seamlessly across borders, cultures, and project teams, integrating effectively with owners, operators, and on‑site personnel to ensure clarity, alignment, and continuity. 

Reflecting on this collaboration, the customer stated: 

“FersiSolar’s experience and proactive approach make them a key partner in our operations, and we are confident in their ability to deliver substantial improvements in solar field performance.” 

Strengthening Long‑Term Operational Capabilities 

Beyond immediate performance improvements, the project simultaneously placed strong emphasis on long‑term operational robustness. Targeted on‑site training and detailed written instructions were provided to support both current solar field strategies and future optimization opportunities. 

Plant personnel were trained with full transparency into calculations, methodologies, and engineering logic, reinforcing technical understanding and operational confidence across the team. 

Results That Extend Beyond the Project Scope 

The result of this collaboration was a solar field operating with improved balance, enhanced temperature control, and stronger performance visibility. Just as importantly, the plant emerged better equipped to sustain and build upon the improvements achieved. 

This project stands as another strong reference for FersiSolar’s role as a trusted engineering and consulting partner for parabolic trough CSP plants worldwide. With experience spanning engineering, construction, commissioning, and O&M optimization, FersiSolar consistently delivers expertise that translates into real operational value. 

To learn more about this specific project competency, or to explore how our services can support your unique solar field, get in contact with us. 

 

Cover image: Redstone power plant in South Africa. Source

How can we make solar power at night? Solar PV is extremely successful at generating solar power during daytime. However, once the sun sets the grid needs to rely on more expensive nuclear, geographically limited hydro or polluting gas and coal. If we want to use solar power during the night, concentrated solar (CSP) is probably the most competitive solution. Making hybrid PV-CSP and PV-wind-CSP plants to tap into the strengths of the different renewable technologies might be the best way to have cheap, low-carbon electricity 24 hours per day.

Thermal energy storage with molten salts – the key to 24/7 solar production

Why is CSP better than PV for providing power at night? It is that the two solar technologies have different outputs. While PV panels provide us with electric current directly, CSP creates heat – steam that needs to run through a turbine to generate electricity. The ace up CSP’s sleeve is that thermal energy can be stored much more easily than electric energy.

Most thermal storage technologies use the sensible heat of a fluid – usually molten salt. The salt heated from the solar field is stored in the hot tank, where it remains at up to 550ºC until the electricity prices become attractive enough for the plant to start producing. Once the salt leaves the hot tank, its energy is passed to the water that circulates in the power block through a heat exchanger. With its temperature now low, the salt is sent to the cold tank. There, it is kept above its freezing point (well above 100ºC) to ensure it doesn’t solidify before the next production cycle begins. This is a rather efficient roundtrip, with up to 99% of the produced energy arriving at the power block.

Figure 1: Schematic of a molten salt storage system with two tanks. Source link.

Compared to batteries (BESS), thermal storage (TES) using molten salts can offer lower costs and avoids issues surrounding batteries’ toxicity and flammability. From an environmental point of view, molten salt TES can offer rather low impacts in a wide range of categories, including acidification, marine and human toxicity and embodied greenhouse gas emissions.

Another advantage that molten salt TES has over battery systems is its lifespan. BESS, for example lithium-ion, typically last 10 to 15 years, with performance degrading after a number of cycles due to chemical aging and thermal stress. In contrast, TES systems using molten salts can last up to 30 years with minimal degradation, as they rely on simple heat transfer rather than electrochemical reactions.

The lower price tag holds true, especially when considering a larger system that could offer sustained output over multiple hours, as shown by a study by the TU Wien below. Although battery energy storage systems have enormous potential for cost reductions, it is highly unlikely that a battery system designed to store electricity for more than 2-3 hours will ever be cheaper than its molten salt counterpart. Thus, even though BESS are absolutely essential for the future grid and should be installed at massive scale, there are niches in which TES outperforms them.

Another important takeaway from the same study is that it is unlikely that PV-TES systems (using some form of heaters as an intermediary) will become more economical than CSP-TES. This ensures the future of CSP itself as part of the energy transition.

Figure 2: Specific costs of different combinations of technologies. BESS – battery energy storage system. TES – thermal energy storage. CSP – concentrated solar power. PV – photovoltaics. Source link

Hybrid renewable plants with storage – closing the gap in energy production

The promising way forward then seems to be to design hybrid plants, where PV panels with some BESS take care of electricity supply during the day, while CSP with TES keeps the lights on during the night. Clearly, CSP can be integrated with wind energy too, not only with PV. In that case, rather than strictly operating at night, the CSP can focus on moments with low winds.

According to a study by researchers from the University of Calgary, if a solar-only plant wants to sustain a continuous load for more than 8-9 hours, the hybridization of concentrated solar power with thermal energy storage (CSP-TES) and photovoltaics with battery storage (PV-BESS) systems offers significant financial benefits. According to their results (see graph below), a hybridized plant designed to run uninterruptedly for 24 hours could have a lower levelized cost of electricity compared to a PV-BESS plant designed to provide 4 hours of service per day.

Figure 3: Levelized cost of electricity of different plant configurations at locations in Morrocco (Ouarzazate) and Italy (Ottana). Source link

The Chinese government has understood this. In the last year of 2024 alone, three projects with 250 MW of CSP were commissioned, all of them hybrid plants, combining CSP with PV and onshore wind (see page 27 here). All projects featured at least 8 hours of thermal storage, allowing for nighttime operation and peak shaving. And there are more projects on the way, 3.3 GW of CSP is under construction, with most of these projects expected to be completed in 2025 (page 28 here).

It is important to stress that these hybrid projects are significantly bigger than only their CSP part, because CSP and PV are not competing with one another, but working together. For example, the capacity of the projects finished last year sits just above 1.5 GW, six times larger than the CSP components alone. The fact that CSP plants are more expensive and require more maintenance than their photovoltaic cousins, gives them a specialized, but absolutely crucial role in the toolbox of the future renewable energy mix.

At FersiSolar S.L. we are experts at CSP, Storage, Concentrated Solar Heat for industries and businesses. If you want a 24/7 clean energy solution, contact us. The world cannot wait…

Or maybe you know any other ways to address this frontier of renewable energy??