Second-Life Lithium-Ion Batteries for Circular Energy Systems: A Techno-Economic and Environmental Pathway to Affordable Grid-Connected Renewable Storage.

The rapid electrification of transportation is generating a growing stream of retired electric vehicle batteries, creating challenges in battery waste management and the provision of affordable energy storage for renewable energy integration. Repurposing these batteries for stationary applications offers a circular-economy solution that addresses both issues. This study evaluates the techno-economic and environmental viability of integrating containerized second-life lithium-ion batteries (SLBs) into a grid-connected hybrid renewable energy system (HRES) for a residential community in Kuala Lumpur, Malaysia. Using HOMER Pro, four configurations incorporating either new or second-life batteries were compared. The results show that the HRES-4 configuration reduces grid dependency by more than 54%, transforms the system into a net energy exporter (>820 MWh/year), and achieves the best economic performance, with a net present cost of $239.6K and a levelized cost of storage of $0.072/kWh. Despite higher degradation rates, SLBs deliver energy throughput and cycling performance comparable to new batteries, exceeding 207 MWh/year and 230 equivalent full cycles annually. SLB integration also avoids approximately 1161 tons of CO2/year, with a carbon payback of 7.13 years. These findings show that containerized SLBs offer a cost-effective and scalable pathway for circular energy systems, with relevance to circular-economy policy and emerging power grids.