Life cycle assessment for a grid-connected multi-crystalline silicon photovoltaic system of 3 kWp: A case study for Mexico

A first life cycle assessment study for the evaluation of a grid-connected photovoltaic system in Mexico was carried out from a cradle-to-grave perspective. The photovoltaic system consists of 12 modules integrated with a multi-crystalline silicon technology with a southward inclination of 20 degrees, a 2.5 kW inverter, and a total installed capacity of 3 kWp, which provides an annual average production of 1282 kWh/kWp with a performance factor of 0.75. This system was installed in a building located in Mexico City. Potential environmental impacts from this photovoltaic system were analysed in eleven categories. The life cycle results show that this technology is within the cleaner energy sources with least environmental impacts throughout its life span. The major environmental impacts were attributed to the production stage, and more specifically, to the manufacturing of materials for the solar modules (which include PV panels, solar cells, and wafers). The multi-crystalline silicon photovoltaic system evaluated in this study was also compared with three conventional photovoltaic generation systems based on different technologies (i.e., single-crystalline silicon, the amorphous silicon, and the copper-indium-selenium solar cells). From this life cycle assessment, it was found that the multi-crystalline silicon system almost systematically exhibits the lower environmental burdens in most of the impact categories (six out of the eleven), in comparison with other systems which present larger contributions of pollutants during their life span. Regarding to the carbon footprint, it was found that the photovoltaic technology with the lowest global warming potential was related to the multi-crystalline silicon system (47.156 g CO2-eq./kWh), whereas the greatest contribution (69.1 g CO2-eq./kWh) was attributed to the single-crystalline silicon system. By considering these environmental sustainability results, a better technological deployment might be achieved which may help to accelerate, and drive a massive use of solar energy resources towards a clean, sustainable and diversified energy future. Finally, the importance of mapping circular economy opportunities during recycling and waste disposal of materials, and the sustainability trade-offs of solar PV systems have been highlighted as crucial research areas and innovation opportunities for future LCA works.