# Assessment of Impacts of Climate Change on Hydropower-Dominated Power System--The Case of Ethiopia
## 3 Result and Discussion
### Carbon Dioxide Emissions  
The residual balance between hydropower generation and electricity demand represents the remaining electric demand that must be fulfilled with alternative electricity technologies (both renewable and non-renewable). This may result in extra GHG emissions depending on the mix of electrical resources utilised for this purpose. The additional GHG emissions associated with supplying the remaining power demand with various energy resources contributed yearly average emissions, as shown in Figure 6 for the period of 2015-2065.  
Figure 5: Comparison of electricity exports (GWh) between Drought and New Policy Scenarios.  
The government's vision is to achieve universal access and meet its future electricity needs without increasing greenhouse gas (GHG) emissions during 2010-2030. Overall, the emission from the New Policy and Drought Scenarios seem to experience more or less comparative similar trends in the modelling period. Renewable energies are gradually replacing fossil fuels and increasing electrification rates across the sector. The CO\({}_{2}\) emissions in both scenarios will be below 1 Mt CO\({}_{2}\) starting in 2015 and will steadily decline over the next 20 years until 2045 (see Figure 6), owing to the absence of emission-intensive technologies, and CO\({}_{2}\) emissions could be significantly reduced, as almost all electric power will come from renewable generation technologies. There will be small increases in CO\({}_{2}\) emissions following the penetration of emission intensive technologies between 2045 and 2065, with some fluctuation over time between 2045 and 2055. In both scenarios, the fluctuation is due to the use of HFO and natural gas technologies in 2049, 2054 and 2065 to cover the sharp increase in electrified total demand: 253 TWh (2049), 317 TWh (2054), 461 TWh (2065).  
Under the New Policy Scenario, Ethiopia's CO\({}_{2}\) emissions increase from 0.42 Mt CO\({}_{2}\) in 2015 to 4 Mt CO\({}_{2}\) in 2065, peaking in 2049 at 7 Mt CO\({}_{2}\). The CO\({}_{2}\) emission is expected to increase slightly from 2045 on, as some renewable technologies, especially hydro in 2046, reach their maximum potential before 2065. Furthermore, in the New Policy scenario, CO\({}_{2}\) emissions will be cumulative 2.4 Mt CO\({}_{2}\) during 2015-2030, on average 0.22 Mt CO\({}_{2}\) annually [28]. Under the Drought Scenario, Ethiopia's CO\({}_{2}\) emissions slowly increase from 0.42 Mt CO\({}_{2}\) in 2015 to 7.3 Mt CO\({}_{2}\) in 2065 while cumulative 4.1 Mt during 2015-2030, on average 0.22 Mt CO\({}_{2}\) annually.  
Our results demonstrate that any effort to satisfy the demand during drought season will impact the electricity generation emission. At the end of the modelling period, HFO will be the only fossil fuel based technology introduced into the system since the scarcity created by hydropower is balanced by other renewable technologies such as solar, wind, and geothermal. The CO\({}_{2}\) as a result of HFO electricity production (which is below 16.5 TWh in 2065) is not significant enough to exceed the emission limit; the CO\({}_{2}\) emitted in 2065 is less than 7.3 Mt CO\({}_{2}\). As a result, the demand can be satisfied while maintaining environmental standards. When it compared with INDC 2030 targets year, by 2030, the nation's electric power generation could create less CO\({}_{2}\) than the national average objective of 5 Mt CO\({}_{2}\). The Ethiopia electric production strategy in both scenarios could help the country achieve higher climate targets than the national average, such as below, 1.5 \({}^{\circ}\)C due to the aforementioned reasons of high proportion of renewable technologies in the power sector.  
Figure 6: Comparison of carbon dioxide emissions between Drought and New Policy Scenarios.