Electricity is one of the most vital elements in modern society. Despite its significance tornimprove human life, there are concerns on its environmental impacts. Life CyclernAssessment (LCA) is a well-established tool for assessing the environmental burdens ofrnproducts (goods and services) throughout their life cycles. Several LCA studies werernconducted for electricity generation and supply systems. However, the LCA data ofrnelectricity systems are country specific in their nature. In addition, existing LCA andrninventory modeling efforts are limited to the circumstances of the developed world.rnTherefore, the need to evaluate the environmental performance and to develop countryrnspecific LCA data that describe actual electricity systems remains important.rnThis thesis provides a picture of current electricity system and presents for the firstrntime the LCA results of hydro and wind power systems in Ethiopia. The assessment aims tornmodel existing hydro and wind energy systems and develop LCI and LCA datasets of therncountry per 1 kWh electricity generated. For both case studies, process-based attributionalrnLCA has been applied using SimaPro software version 8.0.1 and ReCiPe 2008 as impactrnassessment method.rnThe main midpoint environmental impacts of Ethiopian hydropower systemrnconsisting of eleven hydropower plants operational in 2013-2017 were: climaternchange(CC): 32 g CO2 eq., fossil depletion (FD): 0.82 g oil eq., freshwater eutrophicationrn(FWEU): 0.000132 g P eq., human toxicity (HT): 0.58 g 1, 4-DCB eq., metal depletionrn(MD):1.04 kg Fe eq., marine ecotoxicity (MET): 0.01 kg 1,4-DCB eq., natural landrntransformation (NLT): 8.3E-04 m2 eq., particulate matter formation (POF): 0.15 g PM10 eq.,rnphotochemical oxidant formation (POF): 0.03 g NMVOC eq., terrestrial acidification (TA): 0.02 g SO2 eq. and freshwater ecotoxicity (FWET): 0.005 g 1,4-DCB eq. per 1kWh electricityrngenerated.rnThe major midpoint environmental impacts of Ethiopian wind farms composed of 3rnwind farms operational in 2015-2017 were: climate change (CC):33.36 g CO2 eq., fossilrndepletion (FD): 8 g oil eq., freshwater ecotoxicity (FWET): 0.023 g 1,4-DCB eq., freshwaterrneutrophication (FWEU): 0.005 g N eq., human toxicity (HT): 9.9 g 1,4-DCB eq., metalrndepletion (MD): 18.7 g Fe eq., marine ecotoxicity (MET):0.098 g 1,4-DCB eq., particulaternmatter formation (PMF): 0.097 g PM10 eq., photochemical oxidant formation (POF): 0.144rng NMVOC eq., terrestrial acidification (TA): 0.21 g SO2 eq. and natural land transformationrn(NLT): 1.4E-06 m2 eq. per 1 kWh electricity generated. The cumulative energy demand andrnthe energy return on investment (EROI) are 0.393 MJ/kWh and 9.2 respectively.rnThe contribution analysis shows that the pre-operation phase of hydropower plantsrncontributes the highest share (62-99%) in most impact indicators, with the exception thatrnthe operation and maintenance phase accounts for about 50 and 90% share in POF and CCrnrespectively. Moreover, medium-scale hydropower plants have higher potentialrnenvironmental impacts when compared to large-scale hydropower plants. Similarly, thernpre-operation phase of wind power is the largest contributor to all the environmentalrnimpacts, with the shares ranging between 82 and 96%. In addition, the sensitivity andrnscenario analyses indicate that the changes in lifespans, exchange rates for parts, capacityrnfactors, transport routes and treatment activities would result in significant changes in thernLCA resultsrnThe results of the assessment show that the lifecycle of wind power generation hasrnmore impacts in most impact categories than hydropower generation, except particulate matter formation (PMF), natural land transformation (NLT) and water depletion. In manyrncases, a single impact category is caused by many processes associated with few lifecyclernstages. This demands the engagement of many stakeholders including academia,rnresearchers, developers, operators and policy and decision-makers.rnIn general, these studies would give insight for operators and developers to payrnproper attention on determination of sites, capacities and lifespans of power plants andrnend-of-life waste management options. More importantly, this study can serve as an inputrnto a comprehensive life cycle assessment database of the national energy system inrnEthiopia, which is in turn vital to develop communication metrics such as EnvironmentalrnProduct Declarations (EPDs) for economically significant export products in Ethiopia,rnincluding electricity itself. However, the results of this study should be interpreted withinrnthe context of the data limitations encountered during the course of the research, namely,rnlack of local datasets for electricity, transport and waste treatment activities relevant tornlocal conditions. Future efforts in Ethiopia should, therefore, be dedicated to undertakingrnthe creation of life cycle inventory databases with a focus on such background systems thatrnwill serve as a backbone for all kinds of LCAs in the country, and in and beyond the Horn ofrnAfrica region at large.