Evaluation of Hydropower Generation and Reservoir Operation under Climate Change from Kesem Reservoir, Ethiopia

Abstract

Climate changes significantly cause the precipitation deficiency and in turn reduce the inflow amount in reservoir affecting hydroelectric power generation. The primary objective of this study was to evaluate hydropower generation and reservoir operation under climate change from Kesem reservoir. Recent Representative Pathway (RCP) scenarios were used to evaluate the impact of climate change on power generation. Power transformation equation and variance scaling approach were amalgamated to adjust the bias correction of precipitation and temperature, respectively. Bias, root mean square error, and coefficient of variation were used to check the accuracy of projected rainfall. The base and future precipitation, temperature, and evaporation trend was analysed using the Mann–Kendall test. The flow calibration and validation were carried out by the Hydrologic Engineering Center-Hydrologic Modelling System (HEC-HMS), and hydropower generation was evaluated with reservoir simulation model (MODSIM 8.1) under climate scenarios. The performance of the model was found good with Nash–Sutcliffe coefficient (NSE) of 0.72 and coefficient of determination (R2) of 0.73 for calibration and NSE of 0.74 and R2 of 0.75 for validation. Projected future climate scenarios predicted increasing and decreasing trend of temperature and precipitation, respectively. For RCP4.5 climate scenario, the average energy generation is likely to decrease by 0.64% and 0.82% in both short-term (2021–2050) and long-term (2051–2080), respectively. In case of RCP8.5 climate scenario, the average energy generation will be decreased by 1.06% and 1.35% for short-term and long-term, respectively. Remarkable reduction of energy generation was revealed in RCP8.5 with relation to RCP4.5 scenario. This indicates that there will be high energy fluctuation and decreasing trend in the future energy generation. The research finding is crucial for decision-makers, power authorities, governmental and nongovernmental organizations, and watershed management agencies to take care for sustainability in the future hydropower generation in the Kesem reservoir.

Spatiotemporal Variability and Trends in Rainfall and Temperature in South Ethiopia: Implications for Climate Change Adaptations in Rural Communities

“…Advances in Meteorology (i) Estimating and flling missing data: Inverse distance or weighting method is most commonly used for the estimation of missing precipitation [40][41][42]. Rainfall data of interpolation using inverse distance weighting (IDW) can obtain more accurate results [43][44][45][46]. Te rainfall at a station was estimated as a weighted average of the observed rainfall at the neighboring stations.…”

Multi-purpose reservoir operation concomitant with estimating hydropower potential using multifarious hydrological models

“…The daily and monthly power created from the simulation model output throughout the course of the entire year of analysis shows that there is significant daily and monthly power generation volatility caused by considerable changes in inflow and outflow [ 5 ]. During the wet season, the inflow to the reservoir is very high and the release increased to generate more power, and during dry season, inflow is less and generates less power.…”

“…Water resources management is the backbone for the economic growth of a developing country [ [1] , [2] , [3] , [4] , [5] ]. The day-to-day activities of all human beings have been deeply connected with water which can be compensated from reservoirs built on streams or rivers to fulfil during the rainy season and meet various demands during dry seasons [ [6] , [7] , [8] ].…”

Investigation of climate change impact on the optimal operation of koka reservoir, upper awash watershed, Ethiopia

“…However, 83% of the population do not have access to electricity [ 16 ]. Therefore, expanding hydropower projects and electricity generation are two of the four pillars of Ethiopia's Climate Resilience Green Economy (CRGE) [ 17 , 18 ]. Therefore, the Ethiopian government has planned to generate 22.14 Gigawatt (GW) of hydropower by the end of the 2030s [ 19 ].…”

“…According to the finding, the energy production of the GERD reservoir exhibited both a rising and a declining signal at the end of the 2050–2059 and 2090–2099 centuries, respectively, whereas the power capacity of the GIBE–III hydropower showed an increasing signal. Another study by Mirani et al [ 18 ] revealed that the hydropower potential of Kessem reservoir in Ethiopia showed a declining trend under the influence of climate. Adera and Alfredsen [ 16 ] also investigated how the Tekeze hydropower reservoir might perform under the influence of climate change.…”