1 Introduction

Electricity is an essential component of any country's infrastructure that contributes to its long-term development. Solar photovoltaic panels (PV) are frequently acknowledged as one of the world's top renewable energy sources (Papamichael et al. 2022). The United Arab Emirates and Dubai, in particular, are concentrating their investments in technology and initiatives related to renewable energy (RE), and by being chosen to house the International Renewable Energy Agency's headquarters (IRENA), the UAE has established itself as a global leader (Obaideen et al. 2021). In this context, Dubai set up policies and mechanisms to ensure the availability and reliability of power supply for current and future generations by implementing best practices to ensure effective operations while conserving the environment and ensuring resource sustainability.

One of the crucial initiatives of HH Sheikh Mohammed bin Rashid Al Maktoum’s ambition to create a green economy in the United Arab Emirates and achieve sustainable development goals (SDGs) is the creation of Mohammed bin Rashid Al Maktoum Solar Park. The MBR Solar Park, the world's largest renewable energy project on a single site with a projected production capacity of 5,000 MW upon completion in 2030, is committed to meeting the UAE Energy Strategy 2050, the Dubai Clean Energy Strategy 2050, and the Dubai Net Zero Emissions Strategy 2050 by producing 100% of its energy from clean sources by 2050 (Obaideen et al. 2021 and DEWA 2019).

It is essential to understand the significance of end-of-life management in the context of sustainable development, mainly when dealing with PV assets. To address the gap in existing research works in the field and build on the need for further empirical investigation, this study explores the most significant variables that affect PV asset performance in UAE and utilises a technical method and approach to provide a proper guide for End-of-life EOL decisions related to PV solar panels.

Although solar panels are designed to withstand environmental pressures and have a lifespan of around 20–30 years (Oteng et al. 2022; IRENA 2021, European-Ukrainian 2021, Parliament et al. 2020 and Sharma et al. 2019), there is a lack of end-of-life management area in existing studies. Most countries need more regulations regarding the proper disposal of solar panels, resulting in the likelihood of many panels being discarded in landfills, which can have harmful environmental effects.

This research paper aims to provide a clear and systematic approach to evaluating the efficiency and performance of PV panels by utilising PV simulation software analysis tools (PVsyst) to investigate system performance which will support the decision-making process regarding the PV asset waste at the mid-life or End-life cycle.

1.1 Problem Statement

The solar asset management sector is developing and maturing at a new level. Power utilities are looking to shift their assets from fossil fuels to cleaner and renewable energy assets to keep up with new chances and challenges. One of the concerns is how to manage solar PV waste after it has served its purpose. End-of-life PV panels are made of high-quality components and provide an excellent opportunity to develop a strategy or framework for managing a significant amount of its produced waste. There needs to be a globally documented framework, process, or mechanism for effectively handling such waste (Papamichael et al. 2022). EU is the only region that has proposed detailed legislation for the disposal and recycling of solar PV components.

1.2 Research Significance and Novelty

This research paper aims to outline the first guideline and decision-making process for the waste of solar assets at the level of Dubai, the UAE, the Arab Gulf, and the Middle East countries. Hence, its novelty by introducing a new approach and proposing a new pioneering solution in this field. The researcher’s goal is to help, guide and encourage the stakeholders to set asset management plans in advance for the EOL End-of-life or Mid-of-life asset cycle of the solar panels considering a 25 to 30 years timeframe. For example, if a PV panel fails in the middle of its lifespan, it could be disposed of or repaired earlier than predicted by the manufacturer. By identifying clear objectives and creating a comprehensive plan for solar assets, the project’s sustainability can be improved, and solar stakeholders can also prevent or avoid unexpected situations.

1.3 Research Questions

The author aims to answer and achieve the following research questions and objectives.

  1. 1.

    What are the primary parameters of PV modules for evaluating performance?

  2. 2.

    What is the most effective approach to evaluating PV panel performance to inform end-of-life (EOL) decisions?

1.4 Research Objectives

  1. 1.

    Maximize the production efficiency and performance of PV systems by adopting asset performance analysis software & tools to support decision-making and evaluate the impact of waste generated by PV assets.

  2. 2.

    Provide guidelines & decision-making procedures during and after solar assets’ lifecycle.

  3. 3.

    Identify effective criteria and parameters for the decision-making process.

2 Literature Review

The use of PV solar panels as a sustainable power source is increasing rapidly. Consequently, a significant amount of annual waste is expected to be produced by the early 2030s, assuming the panels have a lifespan of 20 to 30 years. Hence, it is important to put in place proper guidelines and policies to regulate and manage these systems at their End-of-life stage (IRENA 2021, Papamichael et al. 2022, and Sharma et al. 2019). Several studies (Obaideen et al. 2021, IRENA 2021, Curtis et al. 2021) emphasize the importance of conducting a comprehensive evaluation to understand what actually happens to a PV panel once it reaches its end-of-life. According to (Huxley et al. 2022), there are three main factors to be considered when predicting and evaluating the efficiency of PV panel energy generation, weather data, electrical measurements of energy output, and system technical specification. The Netherlands were pioneering in establishing a model that studies the significant factors affecting PV energy generation, such as dirt, shading, sunlight, system efficiency, panel surface reflectivity, and module temperature. Adopting these models and actual weather data, help in estimating the performance and efficiency of the PV systems.

Several methodologies and tools are commonly presented under the efficiency and performance evaluation of the solar asset that will support future decision-making at the EOL phase such as I-V curve testing, Performance Ratio PR calculation, and PV laboratory flash tests. The I-V curve test helps in understanding and assessing the efficiency and performance by providing valuable information on the panel’s electrical data collected in the site under different operational environments. Moreover, temperature and radiation are two main variables being measured during the test as they can impact panel efficiency. On the other hand, PR calculation indicates the ratio of the actual energy production of the system to its expected energy production under standardized test conditions. A high PR indicates an efficient system, while a low PR indicates functioning issues or inefficiencies. The PR allows efficient system operation and maintenance over time. Whereas the flash test is conducted in a laboratory under a controlled environment and testing conditions, and using specialized software, & equipment for accurate results. The test is recognized globally by PV manufacturers and used to validate performance, quality, and warranty claims. Furthermore, as per (Agyekum et al. 2022) one of the commonly used simulation software in designing power plants optimisation projects and evaluating and investigating the performance and energy production of the plant to assist the site engineers and manufacturer in improving the system design or efficiency is the PVsyst simulation tool. This tool needs specific meteorological data, such as the effect of solar irradiation, temperature, and local environmental conditions, and the electrical specifications of the PV system components for the simulation. The use of PV technology and extensive knowledge is essential for the accurate prediction of system output. Various recent research papers supported the use of this tool (Ahmad and Ahmad 2019; Agyekum et al. 2022; Belmahdi and Al Bouardi 2020; Al‑Zoubi et al. 2021; Ahmed et al. 2021).

3 Research Methodology

I–V curve test, Flash Test, Performance Ratio PR calculation, and PVsyst simulation software are considered the most effective tools in recent studies to evaluate PV performance. PVsyst is a widely used tool known for its convenience and reliability in serving this purpose. Due to the limitations researcher faced to obtain actual I-V site data from organizations since these data are highly confidential, and the Flash Test was not feasible since it requires special laboratories and qualified experts to execute the test. Therefore, the researcher will rely on using the PVsyst simulation software which is a highly reliable and effective tool to indicate PV system performance.

PVsyst simulation software requires specific data (Site Location, Meteorological data, Module Technical Specifications), which are gathered from several sources and used as the input variables. The parameters are classified into two categories: electrical and meteorological. The inclusion of these parameters is crucial for the analysis, as they have a significant impact on the overall performance of each system:

  1. 1.

    Site Location & Meteorological data: The data include average Temperature, Humidity, Wind Speed, and Solar Radiation in specific locations. To compare the effect of UAE’s extremely hot and dry weather on the efficiency and performance of the PV panel in Solar Park in UAE; it was significant to perform a comprehensive investigation of the actual energy performance and losses. Data were obtained from the NASA Meteorological database (Nasa.gov, 2023) for the duration from Jan 2000 – Dec 2021 (22 years).

  2. 2.

    PV Module Technical Specifications (Mechanical Characteristics and Electrical Specification) are gathered directly from the actual site of a solar park located in UAE and from the Technical Specifications datasheet provided by the PV module Manufacturer (Table 1).

Table 1. UAE Average Meteorological and Solar Data (January 2000 - December 2021)

4 Results and Discussion

The software provided several charts and tables to reflect the main performance indicators and metrics.

4.1 Grid-Connected PV System Production and Performance Analysis (Dubai-UAE)

Fig. 1.
figure 1

System Production in Grid-Connected System (Dubai-UAE)

Figure 1 shows system production in the grid-connected system per year equal to 6476 kWh/yr with Performance Ration (PR) = 80% and System loses = 0.25 kWh/kWp/day. This will be discussed further in the upcoming losses diagram.

In the PV industry, PR is a significant measure that is frequently used for warranty claims of PV systems and the validation of the guaranteed power performance provided by the manufacturer/contractor. It is specified in the norm IEC EN 61724 ( Pvsyst, 2022). As defined by PVsyst software, performance ratio PR is the overall efficiency of the system when it is measured compared to the nominal commissioned power (at STC as given by the manufacturer of the PV module) and the incident energy. STC ( Pvsyst, 2022) is a standardised set of conditions used in the solar industry to assess and evaluate the performance of solar photovoltaic systems. Typically, it identifies three specific groups of parameters that serve as a reference point for testing and rating PV modules as follows:

  1. 1.

    Irradiance: The irradiance level is set to 1,000 watts per square meter (W/m2) that the panels are exposed to consistently.

  2. 2.

    Temperature: The module temperature is set to be tested at 25 °C.

  3. 3.

    Air Mass: The air mass factor is set to AM 1.5. When the sun is at a specific angle of 48.2 degrees from the zenith, the sunlight passing through the Earth's atmosphere is modified to match the spectral content and path length.

PV panel manufacturers and testing laboratories can confirm reliable and consistent measurements of module performance using STC, which allows for fair evaluations between different solar modules or systems, providing a common reference point for assessing and evaluating their electrical production.

Fig. 2.
figure 2

(Source: www.jinkosolar.com)

Guaranteed Power Performance by manufacturer

Table 2 illustrates how well the specified solar panel system performed in generating energy over the year (E_Gird) and reflects the performance ratio (PR), which is how efficiently the system converted the solar irradiation into energy in the grid. These PR values range from 77.5% to 83.9%. This indicates that the system reached the cut-off in 22 years which is earlier than anticipated. The manufacturers guarantee a power performance of up to 80.2% until reaching 25 years (Fig. 2). Hence, the researcher can conclude that the panels reached the time for decommissioning and shall be removed from the power system. Furthermore, it is noticeable that the performance ratio was higher in winter rather than the summer, with less shade and more sunlight; this may be credited to the high temperatures observed and experienced during those months, which have an opposing impact on the efficiency of the solar cells. A drop below 78% in June, July, & August, indicating that there might be issues with system components overheating or it could be due to extreme weather conditions such as a rise in temperature or sand storms and dust (Ahmad and Ahmad 2019, Agyekum et al. 2022, Conde at el. 2023). According to (Satya et al. 2021), there is a direct relationship between temperature and solar PV module cell efficiency, where the PV cell’s performance tends to decrease when temperature rise (Conde et al.2023). This happens because of disrupted internal transmission of PV cells leading to problems with the energy movement within the panel which make it work and function less efficiently. Hence, the temperature is a crucial factor in the power-generating process affecting the overall performance. Figure 3 is an illustration of the PR of the given PV system, which is equal to = 80% in a Uniform shape.

Table 2. Energy and Performance Ratio (UAE-Dubai)
Fig. 3.
figure 3

Months Vs Performance Ratio PR (Dubai-UAE)

As shown, Table 3 represents the normalised performance coefficients which are equal to the daily energy of the system (Yf) over the daily output produced energy of the array plane (Yr) = 4.81/6.01 = 80%.

Table 3. Normalized Performance Coefficients (Dubai-UAE)

4.2 Performance Analysis and Energy Losses in (Dubai-UAE) PV System Simulation

The loss diagram shown in Fig. 4 is a key output of all simulations performed by PVsyst software. The figure provides a thorough overview of the energy flow during which the energy is produced and lost at different stages until it is connected to the grid (Ahmad and Ahmad 2019 and Agyekum et al. 2022). The energy flow starts at the stage of global horizontal irradiation; in this stage, it is equal to = 2042 kWh/m2 for the region of Dubai (UAE). At the beginning of the energy flow, there is an increase in the energy equal to (+7.4%), which can be caused by the PV array being titled southward and thus collecting a more significant amount of energy than being horizontal. An important point to make regarding panel orientation is that according to (Tsoukp et al. 2022), the best and most efficient angle to position a solar panel is to rotate it in accordance with the latitude angle of the specific site location to collect the most sunlight and produce the most energy throughout the entire year. For locations with north latitude, the solar panel plate shall be facing south, while for locations with south latitude, it shall be facing south, toward and away from the equator, respectively.

After this rise, the (−1.8%) arrow shows a loss concerning the energy that remained present and active at the previous stage (Agyekum et al. 2022). Following that, the effective irradiation on the collector is determined and calculated by multiplying the final irradiation on the collector by the total collector area = 2145 kWh/m2* 18 m2 coll. This tells the total luminous energy available on the collector. Multiplying this value by the nominal efficiency of the PV module at STC = 20.06% to attain the nominal PV electrical energy = 7759.37 kWh, rounding it up to the nearest whole number will give 7960 kWh. This value will be developed every time the PV modules function at their nominal efficiency.

The following losses (−0.4% & −12.0%) are due to the fact that PV modules don’t operate under STC at their maximum efficiency. In sunny weather conditions, the PV loss due to irradiance level may be lower, whereas, in very hot environments with poor airflow (like Dubai-UAE), the PV loss due to high temperature might be increased. Subsequently, there are losses on the inverter level ( a device that converts DC to AC to be injected in the grid), as shown in the diagram; the inverter has operational losses, which are indicated as efficiency loss =  − 49%. Other losses are null. Since there are no further losses considered, the output of the inverter is equal to the generated power, which is shown at the bottom of the diagram. The output energy is equivalent to = 6476 kWh, which is the electrical energy injected into the grid.

Fig. 4.
figure 4

Loss diagram (Dubai-UAE)

Fig. 5.
figure 5

Months Vs Normalized Energy (Dubai-UAE)

Fig. 6.
figure 6

Months Vs Reference Incident Energy (Dubai-UAE)

4.3 Energy Production and System Output Assessment (Dubai-UAE)

The above two figures are significant in assessing the performance of the PV module. Figure 5 indicates the normalised energy production and losses generated annually in the PV system and helps evaluate the system’s efficiency. Normalised power, collection loss (PV-array losses), and System loss values = are equal to 4.81, 0.95, and 0.25 kWh/kWp/day, respectively. Figure 6 expresses the amount of sunlight reaching the collector, which is relatively stable over the year. Analysing and assessing the reference incident energy in the collector plane support the site engineers and operators in optimising the PV system position and configuration and then maximising the system performance (Agyekum et al. 2022 Tsoukpoe, 2022).

The above two figures discuss the energy generation and injection into the grid by the PV system. The daily system produced energy injected into the grid from the PV system is displayed in Fig. 7. It is noticed that values are less fluctuating between April-August and virtually inconsistent in winter ( December- March), which proves that during summer, the grid is getting the greatest energy injection due to the extended time & greater intensity of solar radiation during summertime (Agyekum et al. 2022). However, there is a significant drop in March that requires further investigation. It might be due to inaccurate weather data values that affected the simulation or due to the overload on the inverter during this time (Agyekum et al. 2022). Figure 8 draw the distribution of the produced power injected into the grid concerning the energy injected into the grid over the year. It is negatively skewed to the left, which means most of the power output takes values between 1500–2500 (W). Figures highlight the seasonal variations and issues the grid exposed, and analysing them asses in improving system performance.

Fig. 7.
figure 7

Months Vs Energy injected into grid (Dubai-UAE)

Fig. 8.
figure 8

Power injected into grid Vs Energy injected into grid (Dubai-UAE)

Fig. 9.
figure 9

Effective Global corr. For IAM and shadings vs Average module temperature during running (Dubai-UAE)

Figure 9 shows how the array’s temperature is changing with varying effective irradiance. The temperature of the collection fluctuated from as low as 11 °C throughout the winter to as high as near 79 °C in the summer, which is too far from STC values (25 °C at 1000 W/m2).

4.4 Technical Evaluation Flowcharts:

Based on the PVsyst results, the researcher propose utilizing Technical Evaluation Flowcharts as valuable tools for confirming that all important factors related to the panel performance is considered and evaluated in the decision-making process. Figures 10 and 11 illustrate a suggested decision-making process for PV panel waste, based on the obtained simulation results of panel efficiency and performance. If panel still functioning efficiently as guaranteed by the manufacturer, asset owner to decide if it shall stay in service, reused, resold, or repaired. Otherwise, if it reached the cut-off limit they may be decommissioned and recycled as per city regulations. This ensures that the best decision is selected based on complete evaluation of all key factors (Figs. 10 and 11).

Fig. 10.
figure 10

Proposed process flowchart for PV performance Evaluation at EOL

Fig. 11.
figure 11

Proposed process flowchart for PV Decision-Making at EOL

5 Conclusion

This study examined the energy production efficiency, system performance, and losses of PV systems in a Solar Park in UAE. The researcher presented through the discussion the most common and effective methodologies used for evaluating PV panel performance to support decisions related to panels reaching the end-of-life (EOL). However, due to limitations, PVsyst software & technical flowcharts were utilised. The findings and analysis allowed for broader assumptions about the system conditions and variations observed and indicated by the researcher. The research objectives were achieved successfully as the critical parameters of the PV module were identified and utilised using the simulation software and were supported by the flowcharts Fig. 34 & Figure-35 for evaluating the performance and reinforcing the final decision.

In summary, the operating temperature plays a vital role in the energy production process using photovoltaic solar panels. High temperatures do affect the efficiency and physical conditions of PV panels. High-temperature weather leads to an increase in the cell’s heat that ruin or burns the cell’s components, reducing its expected lifetime and lowering its performance while operating. This assumption is proved by the result of the UAE solar park simulation that indicated the system reached the cut-off in 22 years with a performance of 80.0%, which is earlier than anticipated. The manufacturers guarantee a power performance of up to 80.2% until reaching 25 years. Accordingly, it is preferred that Solar panels that are less sensitive to temperature are installed in areas with hot climates, as considered in UAE. These factors are to be considered when deciding where to install the solar panels due to their impact on the efficiency and healthiness of the panels.

To summarise the findings:

  • Efficiency of solar panels operating in hot environments is lower due to the heat effect on destroying or burning the internal PV cells components, making it function less efficiently.

After evaluating the PV system’s efficiency in generating energy and power performance, and using the manufacturer’s performance warranty as the benchmark, 80.2% PR after 25 years, for condition monitoring and evaluation, it is suggested to use the provided technical flowcharts (Fig. 34 & 35) to make an adequately evaluated decision for UAE solar park PV system, which might recommend decommissioning the panels since their validity or usefulness reached its end earlier than anticipated. These two tools are significant to support the site engineers, system operators, and manufacturers in optimising the PV system’s healthiness and configuration to maximise the system performance and extend the lifespan, to delay reaching the End-of-life stage.

The following recommendations are proposed to be incorporated into future studies:

  • Manufacturers, clean energy companies, and PV asset owners are encouraged to participate in real data collection through I-V site testing, which will provide an accurate indication of PV system performance and behaviour under real-world conditions. Furthermore, performing laboratory tests can strongly validate and reinforce the results. Overall, it will be a win-win situation for the participating companies to develop and enhance their assets.

  • Economic assessment of PV panels waste management:

    To assess the health of PV assets and determine the optimal point at which maintenance is no longer cost-effective, future researchers to consider specific criteria like tracking the decrease in performance ratio (PR) and decrease in energy yield in accordance with the cost assessment of operation and maintenance (O&M). Hence, making better decisions about when it is economically reasonable to decommission the assets by evaluating these criteria over time.

  • Future research can include the assessment of carbon footprint and CO2 emissions reduction of the in-service PV panels.