Introduction: Due to Brazil’s geographic location, the country is well-positioned to generate energy from renewable sources. With high levels of solar irradiation, the use of photovoltaic (PV) solar energy has grown in recent years, and installations are expected to continue increasing. Assessing lifecycle greenhouse gas (GHG) emissions associated with installing PV systems is key to determining net emissions reductions and evaluating the potential to reduce the carbon footprint of existing PV systems. Materials and methods: This work evaluates the carbon footprint of two rooftop PV systems and one carport PV system installed in São Paulo, Brazil, considering a 30-year lifetime. The lifecycle assessment (LCA) system boundary encompasses manufacturing, PV module installation, and the balance of systems (BOS). We have collected data from Environmental Product Declarations (EPDs) and PV system installation monitoring. Results: Although the electricity-normalized module emissions for the rooftop and carport systems were 13 and 8 g of CO2-equivalent per kilowatt-hour (gCO2e/kWh), respectively, the carport installation had the highest emissions per unit of energy (18 gCO2e/kWh) because its BOS had the highest emissions (10 gCO2e/kWh). Conclusions: The carbon footprint of rooftop systems was lower than that of the carport system, and BOS emissions were a significant share of the carport’s total. Module manufacturing also contributed significantly, and the carport allows the installation of bifacial modules, which increase electricity generation. Aluminum accounted for a significant share of BOS GHG emissions, so procurement of low-carbon aluminum should be considered.
Santos et al. (Thu,) studied this question.