EV batteries usually last longer than the car: Now they are being re-used to power the grid

US electric vehicle manufacturer Rivian has partnered with battery technology firm Redwood Materials to deploy one of the largest grid-scale batteries in the United States using second-life EV batteries. The initial project involves repurposing 100 used Rivian batteries to provide 10 megawatt-hours (MWh) of energy storage at Rivian’s Illinois manufacturing plant. This system aims to reduce operational costs and ease grid load during peak demand periods, showcasing a scalable and cost-effective approach to stationary energy storage. The collaboration highlights the growing recognition that EV batteries often outlast the vehicles they power, retaining significant capacity even after automotive use. JB Straubel, founder of Redwood Materials and former Tesla CTO, emphasises that these batteries represent a vast, untapped domestic energy resource capable of delivering rapid and flexible energy capacity. Redwood has already been active in the second-life battery market, working with General Motors to develop large-scale storage solutions, including a 12MW/63MWh installation in Nevada supporting AI data centres. Rivian’s CEO RJ Scaringe underlines the strategic importance of stationary storage in stabilising the grid and reducing energy costs, particularly during peak demand events such as heatwaves. By deploying energy stored in repurposed batteries, Rivian can alleviate grid strain and avoid costly electricity purchases. This approach not only benefits individual customers but also contributes to broader grid resilience and sustainability. Industry analysts from Morgan Stanley see significant potential in this model, suggesting that repurposing used EV batteries could create a valuable new revenue stream for car manufacturers while improving the economics of both EV production and energy storage systems. However, challenges remain, particularly around integrating batteries with different usage histories and technical specifications into unified systems. Battery expert Iola Hughes notes that while the concept is promising, ensuring compatibility and safety across diverse battery packs will be critical to its success. The Rivian-Redwood initiative marks a notable step forward in the circular use of EV batteries, signalling a shift towards more sustainable energy infrastructure. As the electric vehicle fleet matures, second-life battery applications could become a key element in meeting rising energy storage demands, supporting the transition to a cleaner and more efficient power grid.