Análise comparativa de impactos ambientais associados ao ciclo de vida de energia eléctrica gerada a partir de fontes renováveis: sistemas fotovoltáicos, hidroeléctricos e biomássicos como casos de estudo

Abstract

One of the great current challenges of the energy sector is to produce clean energy, at low cost and with a lower rate of environmental impacts, capable of meeting the growing demand for energy at a global level. Faced with these challenges, there has been a lot of investment in renewable energy sources, such as photovoltaic solar energy, hydro energy and biomass energy. However, while it is true that these sources are renewable and relatively clean, the issue of the impacts caused by these sources is still neglected, and more detailed comparative studies are needed on their impacts over the life cycles of these sources. This work aims to compare the environmental impacts resulting from the life cycle analysis applied to the activities of electricity generation based on renewable sources. For this purpose, three renewable energy sources most commonly used in Mozambique were chosen, namely, solar, hydro and biomass. Environmental impacts related to the renewable energy sources chosen in this study were identified and a comparative analysis was made. As a case study, three technologies were selected, namely, polycrystalline photovoltaic solar panels, hydroelectric reservoir storage and sugarcane bagasse combustion. The analysis was based on Life Cycle Assessment (LCA). For the quantitative analysis, a net generation of 1MWh of electricity was made to feed the public grid. Five categories of common impacts were chosen in the three case studies, namely, Global Warming, Acidification, Human Toxicity, Abiotic Resources Depletion and Water Ecotoxicity. The LCA results of the renewable sources analyzed in this work, when compared, show that the hydroelectric power plant has the best environmental performance and the photovoltaic plant has the worst environmental performance with the highest potential for impacts in all categories of impacts analyzed in this work. In order to analyze the influence of the environmental impacts of a thermal power plant based on fossil fuels in relation to the one based on renewable sources, the quantitative analysis was made based on the LCAs of a natural gas-fired thermal power plant and a generation plant based on the photovoltaic source as being the one with the worst environmental performance. In general, the results show that the hydroelectric power plant has better environmental performance in all categories of impacts analyzed in this work, therefore, it is the source with the lowest potential for environmental impacts when compared to photovoltaic and biomass energy sources.