Energy balance and carbon footprint of verylarge‐scalephotovoltaic power plant

Abstract

Considering Brazil an important player in the global market for the electricity production from solar sources and the recent investments in large power plants through public policies, this work evaluated a very large-scale commercial photovoltaic power plant (VLS-PVPP) performing an attributional life cycle assessment (LCA) in accordance with ISO 14040/44 standards. The comparative results obtained, for 18 impact categories, show that the use of global data tends to overestimate the impacts of energy production in the VLS-PVPP implemented in Brazil, by at least double. When establishing scenarios for different regions of the Brazilian territory, the energy performance and emissions indicators used varied around 17% due to the high sensitivity of the solarimetric radiation index in the modeling. The carbon footprint ranged between 38.3 and 44.8 kgCO2eq/kWh, and the energy payback time (EPBT) ranged between 4.5 and 5.3 years. The fossil energy replacement ratio (FER) indicator was calculated to quantify the power plant sustainability, which, in the best scenario, showed that the system replenishes, with clean energy, 7.7 times the fossil energy used in its construction. The sensitivity study associated with the uncertainty analysis for the manufacturing location of photovoltaic modules showed little influence (about 1%) on these indicators, showing that the decision to import or manufacture PV modules does not involve an environmental bias, overturning this hypothesis. Furthermore, the sensitivity study of the photovoltaic modules showed that the multicrystalline silicon technology is still the best choice compared to the monocrystalline one, since the latter increased the environmental cost of the evaluated indicators by 20%.