Energy and environmental benefits of circular economy strategies: The case study of reusing used batteries from electric vehicles

According to recent literature and technical analyses, used batteries from electric vehicles can still be used, before the final treatment at the end-of-life, in stationary applications that are usually less stressing than the automotive ones. In this framework, a circular economy inspired pathway is emerging between the building and the transportation sector, generally called "second life" of batteries. Used batteries from electric vehicles can be re-used in residential buildings together with renewable electricity generation technologies to improve the matching between the highly variable electricity generation from renewables and the electricity demand in buildings. This study aims to contribute to the assessment of the environmental sustainability of using battery storage systems for stationary applications made of used batteries in substitution of new batteries in a life cycle perspective. The analysis is performed considering an expanded circular system that includes both the functions provided in buildings (provide the electricity required in a residential building for a specific time frame) and in the transportation sector (provide electricity needed for driving until the battery capacity reached about 80% of the rated capacity). The study shows that reusing used batteries as stationary storage systems in residential buildings can enhance the overall environmental sustainability of the two systems considered. In particular, the environmental impacts decrease of a percentage ranging from around -4% (in cumulative energy demand) to -17% (in abiotic depletion potential). The examined strategy can contribute to initiate the transition towards a circular and low-carbon economy.