Gebeyehu, Desta (Professor)Woldeyes, Sebsibie2018-07-112023-11-042018-07-112023-11-042017-05http://etd.aau.edu.et/handle/123456789/7866The purpose of this study was focused on assessment of stand-alone solar photovoltaic power systems performance and reliability for rural electrification in Ethiopia. It was conducted to assess and evaluate the data collections which were administered on samples randomly selected sites installed in the Benshangul Gumuz, Tigray, Oromia and Amhara regions of Ethiopia. About ten sample sites were identified for each regions and data gathering were made using solar photovoltaic systems investigation check list (see appendices I -VI ) for almost two months. The solar and wind master plan of Ethiopia (used as indicated on the solar radiations data) has a huge solar energy potential for rural electrification through the off-grid system in the samples of randomly selected sites of solar home systems (SHS) and institutional systems (like health post and rural primary schools) in the four regions. The data collected were analyzed using descriptive survey; theoretical, mathematical formulation experimental models, emission reduction analysis and PVsyst software analysis. The analysis and interpretation of data have been made according to the objectives. As can be seen from the investigation of SHS oc V was decreased by 1.54V (7%), sc I whereas decreased by 7.961A (97.3%). Thereby, the output power out oc sc P V  I was reduced by 4.37W (21.85%) after installation. Similar situations have been observed for institutional systems too. Based on the findings of this study, the performance and the reliability of stand-alone PV power systems were affected by variety of factors, such as failure of the components, system configuration, maximum power point tracking, system orientation, tracking solar panels and the ambient conditions. Moreover, loss of PV systems have been observed everywhere in the sample sites due to an accumulation of dust, failure of system design, high temperature and shading. Some of these factors may not be the cause for a total failure, but still have a de-rating impact on the output power of a PV system. In fact, any parameter that impacts the output power of a PV system causes a de-rating in its nominal generation, and can potentially degrade its capability to supply the load, and that leads to a reliability issue. So, it is critical to adapt standard design practices of mathematical formulations, experimentally and PVsyst methods by numerical simulation to identify the ways to improve performance and reliability of stand-alone PV power systems for further practicality in the country. Keywords: Stand-alone, Solar photovoltaic system, Maximum power point tracking, System orientation, Tracking solar panels, Performance, ReliabilityenStand-aloneSolar photovoltaic systemMaximum power point trackingSystem orientationTracking solar panelsPerformanceReliabilityThesis