Site data analysis of CPV plants

A method for the prediction of Energy Production (EP) in Concentrating Photovoltaic (CPV) installations is examined in this study. It presents a new method that predicts EP by using Global Horizontal Irradiation (GHI) and the Photovoltaic Geographical Information System (PVGIS) database, instead of Direct Normal Irradiation (DNI) data, which are rarely recorded at most locations. EP at four Spanish CPV installations is analyzed: two are based on silicon solar cells and the other two on multi-junction III-V solar cells. The real EP is compared with the predicted EP. Two methods for EP prediction are presented. In the first preliminary method, a monthly Performance Ratio (PR) is used as an arbitrary constant value (75%) and an estimation of the DNI. The DNI estimation is obtained from GHI measurements and the PVGIS database. In the second method, a lineal model is proposed for the first time in this paper to obtain the predicted EP from the estimated DNI. This lineal model is the regression line that correlates the real monthly EP and the estimated DNI in 2009. This new method implies that the monthly PR is variable. Using the new method, the difference between the predicted and the real EP values is less than 2% for the annual EP and is in the range of 5.6%–16.1% for the monthly EP. The method that uses the variable monthly PR allows the prediction of the EP with reasonable accuracy. It is therefore possible to predict the CPV EP for any location, using only widely available GHI data and the PVGIS database.

Investments in photovoltaic solar power plants continue to increase across all provinces of Türkiye. However, Bursa is not among the regions that receive the highest levels of solar radiation compared to the eastern parts of the country. The Soğuksu power plant, located in the village of the same name in Bursa, was commissioned in March 2017 with an installed capacity of 7 MW. In this study, the actual generation data of the power plant for 2022 were analyzed, and the performance ratio (PR) and capacity factor (CF) were calculated. The results show that the minimum electricity generation occurred in December 2021 with 401.21 MWh, while the total electricity production in 2022 reached 10.64 GWh. During the summer season, the plant generated 7,262.8 MWh, corresponding to 68% of its annual production. The lowest performance ratio was observed in June at 75.1%, while the highest capacity factor was recorded in July at 28%. Furthermore, the performance ratios for November, December, and January exceeded 100%. Since the PR is calculated based on the solar energy values reported in the regional solar atlas, such results indicate a notable discrepancy between the published data and the actual site conditions. The exceptionally high PR values during the winter months may suggest that the region experiences milder winters and receives higher solar radiation than the atlas values imply.

Finding maximum independent sets in graphs with bounded maximum degree is a well-studied NP-complete problem. We study two approaches for finding approximate solutions, and obtain several improved performance ratios.The first is a subgraph removal schema introduced in our previous paper. Using better component algorithms, we obtain an efficient method with a Δ/6(1+o(1)) performance ratio. We then produce an implementation of a theorem of Ajtai et al. on the independence number of clique-free graphs, and use it to obtain a O(Δ/loglogΔ) performance ratio with our schema. This is the first o(Δ) ratio.The second is a local search method of Berman and Fürer for which they proved a fine performance ratio but by using extreme amounts of time. We show how to substantially decrease the computing requirements while maintaining the same performance ratios of roughly (Δ+3)/5 for graphs with maximum degree Δ. We then show that a scaled-down version of their algorithm yields a (Δ+3)/4 performance, improving on previous bounds for reasonably efficient methods.KeywordsLocal SearchMaximum DegreePerformance RatioFree GraphIndependence NumberThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

This article studies a submodular batch scheduling problem motivated by the vacuum heat treatment. The batch processing time is formulated by a monotone nondecreasing submodular function characterized by decreasing marginal gain property. The objective is to minimize the makespan. We show the NP‐hardness of the problem on a single machine and of finding a polynomial‐time approximation algorithm with the worst‐case performance ratio strictly less than for the problem on parallel machines. We introduce a bounded interval to model the batch processing time using two parameters, that is, the total curvature and the quantization indicator. Based on the decreasing marginal gain property and the two parameters, we make a systematic analysis of the full batch longest processing time algorithm and the longest processing time greedy algorithm, and propose the instances with the bound of batch capacity for these two algorithms for the submodular batch scheduling problem. Moreover, we prove the submodularity of batch processing time function of the existing batch models including the parallel batch, serial batch, and mixed batch models. We compare the worst‐case performance ratios in the existing batch models with those deduced from our work in the submodular batch model. In most situations, the worst‐case performance ratios deduced from our work are comparable to the best‐known worst‐case performance ratios with tailored examinations.

This paper presents an industrial approach to assess the performance of large-scale solar plants (LSSPs) has been developed using a novel performance ratio (PR) formula model based on energy production. The PR is an important quality indicator used for the LSSP projects with a nominal installed capacity of 20 MWdc upward. When solar power plants are put into operation on the national grid, the PR can be used as a performance indicator to ensure the energy guarantee and the plant’s efficiency required to guarantee a level of performance. Then, PR gives the real face of the plant’s efficiency. This is not an easy task because it has no constant value over the years due to the effective incident global irradiation (GlobInc) value always not being available. For this purpose, the proposed PR formula model is used to compute the correct performance guarantee of the grid-connected 100MWdc-LSSP in Pakistan’s Quaid-e-Azam Solar Park (QASP). The main purpose of this study is to incorporate a PR formula based on energy production evaluation to achieve the energy guarantee (excess energy, bonus energy, or energy shortfall) in LSSPs. The 1-year on-site plant data is utilized to investigate the plant’s performance energy inputs such as production, irradiance, PR, and the excess energy. Based on the actual annual energy output and irradiance of the plant, the following results are obtained: Actual PR is achieved at a higher level than the target benchmark, so no shortfall or liquefied damage (LD) is imposed due to excess energy. Thus, 100MWdc-LSSP’s power generation is found to be 5% higher than expected by using the theoretical calculations of PR. In FY (2018–2019), the system fed 0.34% higher PR, with an actual PR of 76.58% higher than the target PR of 76.24%, and extra energy of 710.72MWh produced, as well as bonus energy of 142,143.62 USD. The majority of LSSP projects are determined to be successfully operational and generate a significant amount of power, but they fail to meet the contractual requirements for energy guarantee because they use the incorrect PR formula and also fail to provide the desired energy to stakeholders owing to a poor theoretical assessment of the PR criteria based on energy production. As a result, solar power plants confront a great energy shortfall for many years to come.

The 15 kW solar power plant (PLTS) is a new certain in the application of small-medium solar energy usage, especially for the campus environment in Indonesia which can support and become proof of realization green campus program. The existence of 15 kW PLTS become an attention to do advanced analysis in order that production of the specific electric energy or final yield (YF) and performance ratio (PR) from a PLTS can be monitored based on installation location. The value of YF and PR can be used as reference to do identification, trouble operation analysis, and developing of a PLTS. The optimum value of YF and PR on the 15 kW PLTS resulted by doing simulation from a simulator software, which the value resulted from location and configuration of the system installation without watch shading factor. And then the simulation value compared with electric energy real production result on this 15 kW PLTS. The 15 kW PLTS divided be two lines, that are 5 kW and 10 kW line. From simulation result, showed that in the 5 kW line have value of optimum production is 5264.8 kWh with PR 83,1% and in the 10 kW line have value of optimum production is 7687.2 kWh with PR 83.12%. Real production in line 5 kW is 1326.9 kWh with difference 74.79% with simulation and in line 10 kW is 1643.3 kWh with difference 78.62% with simulation. The shading and existing disturbances resulted in a decrease in electrical energy production and performance in the line 5 kW is YF 0.91 hours/day with CF 2.79% and in the line 10 kW is YF 3.07 hours/day with CF 11.73%.

Concentrator PV systems utilize different part of solar irradiation arriving at the Earth's surface and typically generate different power profiles than traditional flat plate PV or thin film. These factors need to be taken into account during plant design, particularly for inverter sizing strategies, and will result in very different inverter size/ rated DC power ratios than flat plate PV systems. This paper describes a methodology for sizing inverters for CPV power plants that optimizes the financial return of a project, taking into account energy generation profiles and financial parameters for large scale projects. Using hourly CPV power output throughout the year for a number of locations with high Direct Normal Irradiance (DNI) in southwest US, the optimal inverter size to maximize financial return over the project term is determined taking into account the magnitude and financial value of inverter energy clipping, capital and on-going costs and other project financial parameters. This analysis demonstrates the value of inverter sizing to CPV rated power ratios at or close to 1:1 at CPV standard operating condition (SOC) rating (850W/m2 DNI, 20°C Ambient, On-Sun), or 1:1.25 at standard testing condition (STC) rating (1000W/m2 DNI, 25°C Cell). Concrete examples of how this methodology was applied to several commercial and planned SolFocus sites are presented.

Key performance ratios indicate the underlying level of performance and health of the enterprise. Therefore, understanding the components of the final accounts and their performance ratios is important because of the crucial nature of ROE. Even though PRA represents one of the best ways to compare the performance of a business and its peers in the same industry it could be highly distorted due to taxation challenges, hidden gains or losses as well as the issues of window-dressing. Generally, ratios look at the path an enterprise appears to be moving towards as well as its recent performance and current financial situation so as to guide management actions with the aim of enhancing ME. The exploratory research design was used for the study. There were 66 participants in the study and data were collected from both primary and secondary sources. The multiple method of data generation made it possible for data of the study to be compared and contrasted with each other. Data were analyzed through descriptive and regression statistical methods. The result showed a strong positive correlation between PRA and ME. The study was not exhaustive; therefore, further study could examine the relationship between PRA and Trade Debt in Nigeria as a way of helping firms chart a way of meeting their debt obligations. On the basis of the result of this study it was suggested that management of companies should institutionalize effective PRA mechanism adequate enough to track performance at regular intervals.

We consider the problem of partitioning a set of n numbers into m subsets of cardinality k = ?n/m? or ?n/m?, such that the maximum subset sum is minimal. We prove that the performance ratios of the Differencing Method of Karmarkar and Karp for k = 3,4,5, and 6 are precisely 4/3, 19/12, 103/60, and 643/360, respectively, by means of a novel approach in which the ratios are explicitly calculated using mixed integer linear programming. Moreover, we show that for k ? 7 the performance ratio lies between 2-2/k and 2-1/(k-1). For the case that m is given instead of k, we prove a performance ratio of precisely 2-1/m. The results settle the problem of determining theworst-case performance of the Differencing Method.

MAX SAT approximation beyond the limits of polynomial-time approximation

The thermal performance of photovoltaic (PV) modules is a critical factor influencing their electrical efficiency, energy yield, and long-term reliability, particularly in hot climate regions characterized by high ambient temperatures and intense solar irradiance. This study presents a comparative thermal performance analysis of mono-crystalline, poly-crystalline, and thin-film photovoltaic modules under real operating conditions. The experimental framework included continuous monitoring of module temperature using thermocouples and infrared thermal imaging, along with simultaneous measurement of key environmental parameters such as solar irradiance, ambient temperature, wind speed, and relative humidity. The objective was to quantify thermal behavior, evaluate temperature-induced electrical performance degradation, and compare long-term thermal efficiency and energy yield across different PV technologies. The results demonstrated that module operating temperature has a significant impact on electrical performance, with increased temperature leading to reductions in open-circuit voltage, maximum power output, and overall conversion efficiency. Mono-crystalline and poly-crystalline modules exhibited higher temperature coefficients, resulting in greater performance degradation under elevated temperature conditions. In contrast, thin-film modules showed lower temperature sensitivity and improved thermal dissipation, leading to more stable electrical performance. Regression analysis confirmed a strong negative correlation between module temperature and power output for all PV technologies, with thin-film modules exhibiting the lowest thermal derating. Long-term performance evaluation revealed that thermal effects significantly influence energy yield and performance ratio in hot climate environments. Although mono-crystalline modules provided higher nominal efficiency under standard test conditions, thin-film modules maintained more stable energy production and thermal efficiency under sustained high-temperature operation. The findings indicate that thermal resilience plays a crucial role in determining real-world PV system performance and technology suitability for hot regions. Overall, this study provides a comprehensive assessment of the thermal characteristics and energy performance of different PV technologies, offering valuable insights for optimizing photovoltaic system design and technology selection in hot climate environments. The results support the adoption of thermally resilient PV technologies and improved thermal management strategies to enhance system efficiency, reliability, and long-term sustainability in high-temperature regions.

This paper includes a study on the load requirements of houses located in Mandali city, Iraq, as well as design and installation of a stand-alone photovoltaic (PV) system. The utilization of PVsyst simulation software has facilitated the examination of performance ratio with losses. The mean annual energy demand within the residential dwelling is recorded as 4 614,5 kilowatt-hours per year, while the solar panel system is capable of generating 5 731,6 kilowatt-hours per year. However, the energy delivered to the user falls slightly short of the required load, amounting to 4 614,5 kilowatt-hours per year. The diminished power capacity for the system can be attributed to many types of losses. The examination of performance ratios indicates that the month of November exhibited the highest performance ratio (PR) at 87,57 %, while the lowest PR of 50,61 % was seen in April. On average, the PR for the entire year was calculated to be 63 %. The diminished power capacity for the system can be attributed to many types of losse

Building-integrated photovoltaics (BIPV) requires tools that improve and facilitate simulating and predicting the system’s output energy. The efficiency of a photovoltaic (PV) system can be determined by the performance ratio (PR), which relates the actual system’s output energy to the theoretical output according to the installed power and the solar irradiation, thus accounting for the power losses the PV system undergoes. Among the different parameters affecting PR, module temperature and the angle of incidence of irradiance are the most dependent on the BIPV application due to the varied module positioning. This paper assesses the suitability of several BIPV temperature models and determines the angular losses for any possible module positioning. The proposed methodology is easy to replicate and results in polar heatmap graphs to estimate PR at the desired location as a function of the tilt and azimuth angles of the modules. The calculations require irradiance, ambient temperature, and wind speed data, which can easily be obtained worldwide. Dynamic sky conditions are addressed through filters that smooth out quickly changing input data to avoid high and low peaks. The developed graphs are helpful in the decision-making process for BIPV designs by allowing the designer to estimate the expected PR of the BIPV system for any possible position of the modules on the building envelope, reducing the effect of uncertainties and resulting in more accurate and better predictions of the system’s output energy. The method applied to a BIPV façade in Madrid showed a deviation of less than 3% between the estimated and monitored PRs; the PR values ranged between 0.74 and 0.82, depending on the BIPV application and module position.

Graphical abstract of Proposed Floating PV Plant. • Optimized a 200 MW FPV system on Kaptai Lake using PVsyst simulations with 100 design cases. • Best configuration: 22° tilt, 0.8 m spacing, yielding 399.8 GWh/year with 83.21 % PR. • Economic viability: NPV of $226.23 M, LCOE of $0.0433/kWh, ROI 149.2 %, IRR 19.25 %. • Minimized shading (1.71%) and system loss (0.077%) under optimal layout. • Demonstrates FPV as a cost-effective, land-efficient energy solution for Bangladesh. Floating photovoltaic (FPV) systems offer a promising solution for renewable energy generation in densely populated and land-scarce countries like Bangladesh. This study presents a techno-economic optimization of a 200 MW grid-connected FPV plant proposed for Kaptai Lake (22.63° N, 92.24° E). Using PVsyst software (Version 7.4.7), 100 system configurations were simulated by varying tilt angles (18°–27°) and inter-row spacings (0.2–2.0 m) to evaluate energy output, shading losses, performance ratio (PR), and financial feasibility. The optimal configuration—22° tilt and 0.8 m spacing—yields 399.8 GWh annually with an 83.21 % PR, minimal shading (1.71 %), and array/system losses of 0.804 % and 0.077 %, respectively. Economic indicators confirm strong viability, with a Net Present Value (NPV) of USD 226.23 million, Levelized Cost of Electricity (LCOE) of USD 0.0433/kWh, payback period of 5.81 years, 149.2 % ROI, and 19.25 % IRR. Although higher tilt or spacing can increase output marginally, they significantly escalate installation costs (up to USD 190.62 million), undermining cost-effectiveness. This study demonstrates that FPV is not only land-efficient and environmentally sustainable, it reduces 4740316.3 tons CO 2 emission, but also economically viable for large-scale deployment in Bangladesh. The simulation-based approach provides a replicable model for future FPV projects on inland water bodies, contributing to national energy diversification and climate resilience goals.

Numerous assessments have been conducted around the world to characterize using the performance ratio (PR) the energy production (energy rating) of different PV technologies and manufacturers. Experimental results vary between locations and the single PR criterion is not enough to understand the performance variability. Using present modelling tools, energy rating is possible but there are still uncertainties requiring additional data collection and analysis especially in terms of the effects of spectrum, angle-of-incidence and degradation. The Hawaii Islands have high solar resource, spectrum rich in short wavelength and a hot and humid environment expected to rise degradation rate. Testing in Hawaii provides an ideal environment to support research on PV technologies. A PV test platform, commissioned on the island of Maui in February 2016, tests side by side 15 grid-connected PV systems. A new energy rating analysis is proposed where PR is separated into current (IP) and voltage (VN) performances. These additional criteria help understand the performance differences between PV modules and locations which will lead to better select the PV technology to certain environment. This approach also helps identify the parameters of operation to dissociate the impacts of the environmental and operating conditions (soiling, shading). At the Maui test platform, the yearly average PR is estimated between 87% to 98% depending on the PV systems, with 2 thin films (CIGS, CdTe) over performing the standard and high efficient crystalline modules. IP is evaluated between 95% and 100% for most PV manufacturers except for one low (91%, CIGS) and one high (104%, CdTe) performer. VN ranges between 87% and 98%, the CIGS exhibiting high voltage performance compared to the other technologies.