Evaluation of a grid-connected photovoltaic system and in-situ characterization of photovoltaic modules under the environmental conditions of Mexico City

Abstract

In this work we present the results of the monitoring and statistics of a grid connected photovoltaic (PV) system located on the roof of the building occupied by the ``Instituto de Ciencia y Tecnología del Distrito Federal'' (ICyTDF), at the historical center of Mexico-City (DF). The on-grid connected photovoltaic system has 6150 Watts peak (Wp). This system ensures a daily mean reduction of 30 kW.h in the consumption of electric energy at the ICyTDF facilities; which results in a significant saving of fossil fuels and avoiding the emission of greenhouse gases. This system can generate an annual average of 10.8 MW.h of electrical energy, equivalent to burning 0.87 tonnes of oil which would lead to the emission of approximately 2.1 tonne/year of CO$_{2}$ into the atmosphere. The ecological impact of the photovoltaic system installed in the ICyTDF is equivalent to a forest area with more than 700 adult trees (7 hectares of forest). We also report the analysis of the PV-performance in real time of several commercial solar modules, manufactured with different materials and technologies, these results may give an indication of the comparative performance of the technologies under the environmental conditions of México City. Four different solar modules made of monocrystalline silicon, polycrystalline silicon, amorphous silicon and CdS/CdTe technologies were tested. The outcome of this study is that a better performance was noted for modules made of amorphous silicon technology under temperature variations typical of Mexico City's environmental conditions.