Abstract:Fourteen (14) rack-mounted polycrystalline modules installed on the concrete roof of the solar energy applications laboratory at the Kwame Nkrumah University of Science and Technology (KNUST) in Ghana, a hot humid environment, were assessed after 19 years of continuous outdoor exposure. The physical state of the modules was documented using a visual inspection checklist. They were further assessed by current-voltage (I-V) characterization and thermal imaging. The modules were found to be in good physical state, except some bubbles on front side and minor discolouration/corrosion at edge of the cells. Compared with reference values, the performance decline of the modules observed over the exposure period was: nominal power (P nom ), 21% to 35%; short circuit current (I sc ), 5.8% to 11.7%; open circuit voltage (V oc ) 3.6% to 5.6% and 11.9% to 25.7% for fill factor (FF). It is hoped that this study will provide some helpful information to project developers, manufacturers and the research community on the long-term performance of PV modules in Ghana.
Solar photovoltaic (PV) technology has attracted an enormous amount of attention and investment in recent years—translating to record deployment levels. This is due to in part to its potential role as a cleaner energy source in the emissions‐constrained development agenda that is currently being pursued at both global and national levels. Solar PV has also been propelled to the forefront of today's menu of technological options by virtue of its attributes such as scalability, fast deployment lead times, and low operating cost. Substantial investments are needed in the coming years in order to accomplish climate targets and other goals set by various countries and regional/subregional blocs. In support of informed investment decision‐making and ultimately, improved outcomes of solar PV projects, there has been an uptick in studies on operational performance of fielded PV systems across the globe. These studies are, however, geographically unbalanced, and there is the need for data from underrepresented regions. This paper presents a synthesis of results obtained from recent seminal field studies on PV module performance degradation in Ghana. The studies altogether analyzed sixty‐five (65) modules (mono‐ and polycrystalline silicon) from twenty‐nine (29) installations across the country (1118 module‐years). The field‐aged modules were characterized in situ using current‐voltage (I‐V) curves, visual inspection checklists, and thermal imaging. Annual module performance degradation rates (peak power) of 0.8%‐7%, 0.55%‐2.07%, and 1.1%‐2.4% were found for modules located in various climate subcategorizations.
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