Improving the performance of photovoltaic systems by increasing their annual energy production, reducing system capital costs and operating and maintenance costs is a global priority and implies a permanent concern for evaluating and increasing their efficiency. Starting from the calculation of the efficiency of a photovoltaic panel at the customer, according to the catalog data, with calculation examples, the article analyzes the three stages for determining the efficiency in the laboratory: measuring the spectral response (SR), determining the amount of external and internal efficiency and drawing the graph the current-voltage (I-V) characteristic to evaluate the electrical efficiency. The main objective of the article is to provide clear and concise analysis for laboratory tests of photovoltaic cells and panels.

The article emphasises both the advantages and disadvantages of photovoltaic power plant deployment, assessing the current stage of development as well as the deficient characteristic criteria, such as the occupied specific surface area or the associated unpredictability. The authors consider that current technologies related to photovoltaic plants provide a maximum efficiency of approximately 28%. Consequently, management methods must be applied in order to improve efficiency and eliminate the reported deficiencies. When assessing a medium- to high-power PV plant, the initial investment, projected efficiency, and parameters of the desired plant are correlated, and sometimes, a cheaper and less efficient power plant can be recommended. Although solar trackers may represent a viable solution in certain scenarios, their effectiveness is strongly influenced by various factors, including panel orientation, climatic conditions, installed capacity, and the specific technologies. These variables can significantly affect such systems’ overall efficiency and suitability. The present study proposes a statistical approach to assessing the economic efficiency of photovoltaic systems equipped with solar trackers, aiming to enhance energy production performance. The results are correlated and validated using field data obtained from existing literature studies to ensure the reliability and accuracy of the analysis. For a better analysis, the paper presents two methods, ANOVA and STEM, which are derived from quality control. The novelty aspect of this proposal consists of the combination of specific data obtained from the PVGIS platform with a new approach for optimisation of energy production in photovoltaic systems based on geographical coordinates. The STEM statistical method provides a high degree of novelty because, although it is a well-known method, it has not yet been applied to analyse the technical and economic efficiency of photovoltaic systems. One of the main advantages of this method is its ability to incorporate a wide range of technical and economic performance parameters. A case study is provided to evaluate the benefits of implementing the STEM method.

The paper analyzes the possibility of using a Cross-Flow hydraulic turbine (Banki–Michell type) in a micro-hydropower plant located on the Dâmbovița River, in the Conțești area. The study starts from the current context of the energy transition and the need for the development of renewable energy sources, highlighting the role of micro-hydropower plants in exploiting local hydraulic resources and increasing the energy security of rural communities. Based on the hydrological data of the area and the engineering calculations made, the electrical power and annual electricity production were estimated. The sizing of the turbine, penstock, and generator confirms the technical feasibility of implementing a micro-hydropower plant of this type. The techno-economic analysis indicates an estimated investment of approximately €130,000, a payback period of about 6.8 years, and a positive NPV, which demonstrates the economic viability of the project. In addition, the environmental impact is low, and energy production is achieved without direct CO2 emissions.

This article examines the advantages and disadvantages of deploying photovoltaic power plants in residential areas, considering both their current development status and specific operational risks, such as the unpredictability associated with potential faults. It highlights that errors of existing PV technologies can pose risks, including the potential for fire and electrocution. To improve efficiency and address these identified issues, the paper emphasizes the benefits of using additional electronic equipment, called “optimizers”, which, in conjunction with the inverters, can provide arc-fault circuit interruption and rapid shutdown of the photovoltaic systems. These technologies are designed to reduce faults and enhance operational safety, thereby reducing the risk of electrocution for maintenance personnel. They are recommended especially for rooftop PV systems that are affected by shading conditions. Furthermore, experimental results indicate that the use of such optimizers can lead to a power gain of up to 50% in partial shading.