## 1 Introduction
Stable energy production using \(PV\) power plants requires energy storage to buffer supply imbalances. If short-term electricity storage is required, batteries are the solution, as they are highly efficient and flexible [16]. On the other hand, if long-term storage is required, hydrogen-based systems are more effective [17]. The problems indicated above do not reduce the importance of \(PV\) power plants in the electrical system. The energy production of a \(PV\) power plant is a fundamental factor in its design. Therefore, it is necessary to analyse the \(PV\) module mounting systems, as energy production depends on this choice. \(PV\) module mounting systems can be classified according to the presence of moving parts in their structure. Therefore, the first classification will be whether the mounting system has moving parts or not. If it has no moving parts, they are called fixed tilt angle systems. If they have moving parts, they can be classified according to the number of rotation movements [18]: dual-axis trackers and single-axis trackers. The latter can be classified, in turn, into horizontal single-axis trackers, vertical single-axis trackers, and polar single-axis trackers. The horizontal single-axis tracker is the most widely used of the three [19]. The presence of moving parts in the structure of the mounting system will be a fundamental aspect in its analysis. As will be shown in detail in Section 2, a key aspect in the design phase of a \(PV\) power plant is the choice of \(PV\) module mounting system. In this selection, several criteria are used, all of them related to the presence of moving parts in the structure of the mounting system. These criteria are as follows: the energy production, the reliability, the durability, the simplicity of installation, the maintenance costs, the initial costs, the vulnerability to extreme environmental factors, the limitation of geographical location, the budgetary considerations, and the environmental impact. Therefore, depending on the location of the \(PV\) power plant, some of these criteria will be more suitable for a specific \(PV\) module mounting system. Optimising all the criteria at the same time is not possible. This study focused on energy production. One of the strengths of the dual-axis tracker is that, due to its two rotational movements, energy production is high [18]. However, it has high maintenance costs [20], lower reliability [21], and lower durability [21]. The weaknesses of the dual-axis tracker are the reasons for prioritising the use of horizontal single-axis trackers in \(PV\) power plants [21]. According to a report by Mordor Intelligence [22], the global solar tracking systems market was dominated by horizontal single-axis trackers in 2024, with a market share of approximately 92%. The future prospects for horizontal single-axis trackers are very promising. The market size for this solar tracker is estimated at USD 55.93 billion in 2025, and this market is forecast to reach USD 146.28 billion in 2030, with a compound annual growth rate of 21.2% during the forecast period (2025-2030). Therefore, this was one of the \(PV\) module mounting systems analysed. The other mounting system studied was the fixed tilt angle system, since the parameters--maintenance costs, reliability, durability, and initial cost--are much better than those of the horizontal single-axis tracker. From sunrise to sunset, the \(PV\) field of a fixed tilt angle system always occupies the same position. In contrast, a horizontal single-axis tracker has three operation modes [23]: (i) backtracking mode, (ii) static mode, and (iii) normal tracking mode. Figure 1 shows these three operation modes. The backtracking mode is characterised by avoiding shading between adjacent solar trackers at the expense of not maximising the incident solar irradiance on the \(PV\) field. When the solar altitude is low, i.e., at sunrise and sunset, shadows can occur between solar trackers, and this is when the backtracking algorithm is used.