# Determination of Effective Parameters for Hydropower Plants' Energy Generation: A Case Study
## 4 Results and Discussion  
The energy generation of a hydropower plant may be impacted by several factors, which might vary depending on the specific design and geographical location of the facility. Hydropower energy generation is mostly affected by seasonal variations, which are principally driven by alterations in precipitation patterns, temperature fluctuations, and water availability. Comprehensive and effectively controlling the fluctuations in seasons are vital in order to maximize the efficiency of hydropower facilities and guarantee an adequate and uniform supply of electricity over the whole of the year. Within the context mentioned, effective parameters for the energy generation of a selected hydropower plant, named Bagisli HPP, have been comprehensively investigated based on the daily data related to flow rate, precipitation, and temperature compared to energy generation. Figure 8a-d illustrate the variation in monthly total precipitation, flow rate, and energy generation data, whose sources have been mentioned before, with respect to each other for the given time interval of 2016-2019. It is clearly seen from the figure that flow rate and energy generation have a direct relationship in all sub-figures. When the flow rate reaches its peak level, energy generation also reaches its highest value; thus, the two indicators act in a similar way. Throughout the analysis, the mean daily energy output in May attained the peak value of 640 MWh. Similarly, while analyzing the daily mean flow, it was found  
Figure 7: Daily energy generation of Bagisli HPP for the given years. that the maximum value of the daily mean flow recorded in May was 47 m\({}^{3}\)/s. When analyzing the energy generation data and flow rates in unit days, the energy generated in 2016 was 230 MWh/day with a daily mean flow rate of 12.8 m\({}^{3}\)/s. In 2017, the values were 190 MWh/day and 10.5 m\({}^{3}\)/s, in 2018 they were 226 MWh/day and 11.4 m\({}^{3}\)/s, and in 2019 they were 272 MWh/day and 17.1 m\({}^{3}\)/s. The findings clearly demonstrate that variations in mean daily flow values directly impact energy generation values. However, in some months of the given years, although there was flow in the river, no energy was generated, especially in extremely cold months. This outcome may arise from the freezing of the water in the regulator due to its low level. Figure 8: \(Cont.\)  
Generally, it is known that the link between precipitation and river flow rate (discharge) is of utmost importance in the context of hydropower generation since it directly impacts the accessibility of water that augments the total resources for the purpose of power generation. Figure 8a-d show the variation in monthly flow rate that occurred in the stream gauging station on Zap River, which passes through the Bagisli HPP, with respect to monthly precipitation data. It can be deduced from the figure that a relationship between precipitation and flow rate occurs in the spring season consisting of the months of March, April, May, and June, especially in Figure 8b-d. In the given figures, firstly, the precipitation rate increases and has a peak level, and then the flow rate increases and has a peak, due to the shifting data of precipitation for the mentioned months. When the total monthly precipitation changes by year are analyzed, it can be seen that the peak values in precipitation are obtained in the spring months. However, in Figure 8d, the monthly mean precipitation value in January differs from other years. Prior to the peak value observed between March and April, high precipitation was also observed in January, but it returned to seasonal averages in February. Due to the continental climate of the region, precipitation between December and February is generally in the form of snow. In the relevant months, daily air temperature averages vary between \(-2\)\(\,\mathrm{\SIUnitSymbolCelsius}\) and \(-8\)\(\,\mathrm{\SIUnitSymbolCelsius}\). The instantaneous effect of precipitation in the form of snow on the flow rate may be more limited compared to rainfall.