# Assessment of Impacts of Climate Change on Hydropower-Dominated Power System--The Case of Ethiopia
## 1 Introduction  
One of the four pillars of the Ethiopian Climate Resilience Green Economy (CRGE) initiative was to increase electricity generation from renewable energy sources for local and regional markets [1]. As per the second National Electrification Program (NEP-2), by 2025, grid solutions are expected to account for 65% of access provision while off-grid technology is expected to cover the remaining 35% [2]. Ethiopia has abundant water resources with a capacity to generate over 45,000 Mega Watts (MW) [3]. In just over a decade, the country's power generating capacity had quadrupled, raised from about 850 MW to 4300 MW in 2017. The Government's investments have positioned the country well to become a power hub for their East African neighbours, in harmony with the nation's resilience to climate change and its reputation for being a green economy front-runner, with the hydro Gibe-III Hydropower (1870 MW) and other well-advanced large-scale hydropower projects, most notably, the 5000 MW Grand Ethiopian Renaissance Dam, which is more than halfway through construction [2]. However, ensuring reliable and consistent access to electricity remains the major concern [2, 4, 5, 6, 7, 8]. In recent years, with increasing load demand, the Ethiopian power system has faced more frequent, widely spread and long lasting blackouts [9]. Alongside this initiative, the government is committed to limiting the country's 2030 GHG emissions to today's 150 Mt CO\({}_{2}\)[10]. The emission is mainly due to the traditional and unsustainable ways of utilizing natural resources [11]. As one of the Sub-Saharan countries, Ethiopia is prone to a variety of climatic extremes, including devastating droughts and floods [6]. Drought can be caused by a variety of natural factors including topography. However, it is more linked with climate change. A dual relationship exists between hydropower and climate change. On the one hand, hydropower is a valuable renewable energy source that helps to reduce greenhouse gas emissions and mitigate global warming. Climate change, on the other hand, is anticipated to alter river discharge, affecting water availability, consistency, and hydropower generation [12; 13; 14]. Rivers and reservoirs can dry up as a result of drought. In countries like Ethiopia where hydropower plants are predominant, drought may significantly reduce electrical power generation. Extreme and exceptional drought conditions have been affecting much of the Ethiopian periodic droughts that disrupted hydroelectric power generation, exacerbating the problem and may force decision makers to invest more. One of the largest hydropower plants in Ethiopia (Tekeeze) was out of production for most of its first year as a result of drought. Research studies have also revealed varying levels of climate change impacts on water availability, which is the only input for hydropower [15; 16; 17; 18; 19]. Many researchers have carried out an investigation to look at the effects of climate change on hydroelectric power generation and to propose solutions to the problem. In Kainji Dam, Niger State, Nigeria, empirical research was conducted to examine the effect of reservoir inflow patterns on hydroelectric power generation capacity. First, the study period's overall mean power generation was determined. The effects of inflow on power generation during high and low inflow periods were then explored. The research indicated that reservoir inflow has a strong relationship on the amount of power generated [17; 20]. A study in Ecuador used climate change impact modelling and demonstrated it through application to a hydropower plant in the Rio Jobones Basin. According to its scenario analysis, while hydropower generation will increase during the wet season, the plant will experience a significant power shortage during the dry season, up to 13.14% less from the reference scenario, due to a 17% reduction in streamflow under the assumption of a 2.9 \({}^{\circ}\)C increase in temperature and a 15% decrease in rainfall [21].