Life cycle assessment of a 33.7 MW solar photovoltaic power plant in the context of a developing country

Abstract

Abstract This work aims to determine the Energy Payback Time (EPBT) of a 33.7 MWp grid-connected photovoltaic (PV) power plant in Zagtouli (Burkina Faso) and assess its environmental impacts using the life cycle assessment tool according to ISO 14040 and 14044 standards. A “cradle to grave” approach was used, considering 1 kWh of electricity produced and injected into the national grid over 25 years as a functional unit. In addition to the baseline scenario, the other simulated scenarios combining three variables, module technology (mono c-Si, poly c-Si, and CdTe), type of mounting structure (aluminum and steel), and end-of-life treatments (landfill and recycling) were considered. SimaPro 9.4 software and the ReCiPe 2016 Midpoint (H) evaluation method were used for the calculations considering four environmental indicators. A sensitivity analysis of the change in the electricity mix was also performed. Results showed that the EPBT of the scenarios varies between 1.47 and 1.95 years, with the shortest and longest corresponding to scenarios 4 (CdTe modules, steel mounting structure, and recycling as end-of-life treatment) and scenario 3 (mono c-Si modules, aluminum mounting structure, and recycling as end-of-life treatment), respectively. All the EPBT scenarios studied can be considered acceptable given the long lifetime of PV systems (25 years). The following environmental impact results were obtained: climate change 37–48 CO2-eq kWh-1, freshwater ecotoxicity 4–11 g 1,4-DCB kWh-1, mineral resource scarcity 0.4–0.7 g Cu-eq kWh-1 and 11–13 g oil-eq kWh-1 for fossil resource scarcity. Scenario 3 (mono c-Si modules, aluminum mounting structure, and recycling as end-of-life treatment) dominates all environmental indicators studied except freshwater ecotoxicity, which is dominated by scenario 4 (CdTe modules, steel mounting structure, and recycling as end-of-life treatment). The sensitivity analysis showed that the change in the electricity mix could reduce around 30% the EPBT, climate change, and fossil resource scarcity. Considering the environmental indicators studied, using CdTe modules manufactured in a country with a less carbon-intensive electricity mix, using galvanized steel as the mounting structure, and completely recycling components at the end of their lifetime is the most environmentally friendly scenario. However, particular attention needs to be paid to the land occupation that this plant could generate.

Keywords

• Photovoltaic power plant
• Life cycle assessment
• Energy payback time
• Climate change
• Resource scarcity
• Sub-saharan Africa