Photovoltaic Manufacturing Factories and Industrial Site Environmental Impact Assessment

Life cycle inventories (LCI) and life cycle assessments (LCA) of photovoltaic (PV) modules and their components focus on the operations of PV factories, but the factories and industrial site product and construction stages are either not, or only partially, tackled. This work contributes with the bottom-up, model based, generation of LCIs and LCAs for setting up a vertically integrated 5 GWp/a PV industrial site including the manufacturing of silicon ingots, wafers, solar cells, and PV modules on a 50 ha greenfield location. Two comparative LCAs were performed. The first compares the annualized environmental impacts of the developed LCI sets with four existing inventories in the Ecoinvent v3.8 database. The second comparative LCA explores the environmental impact differences for the industrial site when using different building systems for the factories. Here, the reference system with steel structure is compared with two alternative building systems: precast concrete and structural timber. The results show that the wafer, cell, and module factories annualized environmental impacts with Ecoinvent LCIs are strongly over-estimated. For the ingot factory the opposite result is identified. The impacts for all four factories show reductions between 11.7% to 94.3% for 14 of the 15 impact categories. High mean environmental impacts shares of 79.0%, 78.2% and 79.2% for the steel, precast concrete and timber structural building systems, respectively, are generated at the product stage. The process and facilities equipment’s generate 54.2%, 54.4% and 58.2% of the total product and construction stages mean environmental impact shares. The proposed alternative timber building system re-duces the environmental impacts in 14 of the 15 evaluated categories, with reductions ranging from 1.1% to 12.4%.