# Increasing Photovoltaic Systems Efficiency Through the Implementation of Statistical Methods
## 6 Conclusions  
The statistical analysis, presented using the ANOVA method and the Kruskal-Wallis test, aims to determine the influence of an optimal tilt angle on the season. From the study of the data presented in Table 5, it was found that for May, July, and September (as examples), there is a significant difference in the influence of the tilt angle of the panels. If the time parameter analysed is restricted to the summer months of June, July, and August (Table 8), it was found that there is no significant difference regarding the tilt angle of the panels. Thus, it can be concluded that an alternative method could be to abandon tracking systems and build PV power plants with groups of panels oriented from the beginning under the optimal angle corresponding to each season for systems in temperate areas with four seasons. The novel aspect of this proposal is the combination of specific data obtained from the PVGIS platform with a new approach to optimising electricity production in photovoltaic systems based on geographical coordinates. Instead of using costly tracking orientation systems that require elaborate maintenance, the proposed method suggests dividing the photovoltaic modules into groups. Each group would have a different tilt angle optimised for a specific season. The STEM statistical method presents a high degree of novelty because, although it is a well-known method, it has not yet been applied to analyse photovoltaic systems'technical and economic efficiency. One of the main advantages of this method is its ability to incorporate a wide range of technical and economic performance parameters from both the S1 and S2 categories, as illustrated. By applying this method, we can significantly expand the scope for statistical analysis of the investment efficiency of photovoltaic systems. The statistical analysis leads to a conclusion consistent with the known situation worldwide. Data analysis indicated that, under the conditions considered in this study, the most economically efficient PV power plants use monocrystalline silicon modules and do not employ tracking systems. By correlating data from the PVGIS platform with findings from existing literature, this study aims to provide a clearer perspective to support investment decision-making, particularly by minimising uncertainties related to the strong dependency on various external factors. The analysis revealed that, in most cases, increasing the installed capacity of a photovoltaic system (by sizing a larger array) is more cost-effective than improving efficiency through the use of tracking systems. Nevertheless, solar trackers remain a viable option in specific contexts. This article also discusses the limitations encountered, particularly those associated with the availability and reliability of validation data. Conceptualization, D.-A.S. and E.T. ; methodology, D.-A.S. and E.T. ; software, D.-A.S.; validation, M.-G.M. ; formal analysis, D.-A.S.; investigation, E.T. ; resources, L.-A.E.-L.; data curation, L.-A.E.-L.; writing--original draft preparation, D.-A.S.; writing--review and editing, L.-A.E.-L. and E.T. ; visualization, M.-G.M. and G.C. ; supervision, G.C. ; project administration, D.-A.S.; funding acquisition, L.-A.E.-L. and G.C. All authors have read and agreed to the published version of the manuscript. This work was supported by the Ministry of Research, Innovation and Digitization, CCCDI-UEFISCDI, project no. 61/2024 INFUSE (Information Fusion of Multi-Vector Real-Time Data Streams for Energy Management in Emerging Power Grids), project no. PN-IV-P7-7.1-PTE-2024-0249 (Automated Behavioural Barrier for Biodiversity Conservation by Avoiding Fish Capture in River Water Intakes), and Nucleu contract no. 42N/2023, project no. PN 23140101/2023 (Superior Exploitation of Renewable Energy Sources through Highly Energy-Efficient Equipment Development for Electricity Production and the Intelligent Control of its Distribution and Use). Not applicable. The original contributions presented in this study are included in the article.