In this paper, theoretical bases on the Sun, its motion and solar radiation are given. The procedure of analytical calculation of solar radiation for a specific location and also for determining the optimal angle of inclination of photovoltaic modules at a specific location is also described. A detailed analysis of the geographical parameters of a particular location gave us the necessary knowledge about the dependence of the geographical position of the location and the associated solar radiation. Using the software PVsyst, the operation of the photovoltaic power plant was simulated and the calculation of the annual production for different angles of the photovoltaic module was performed. The analysis of the results of production simulations explains the influence of the angle of inclination of photovoltaic modules on the production curve and on the total amount of production of a solar power plant. Using the available tool, the optimal angle of inclination of the module was also calculated. Also, to investigate the impact of using the Sun tracking system, production simulations were conducted with their use. It has been concluded that Sun tracking systems are a relatively new technology that will develop and in some parts of the Earth they are very likely to find future use.