Rivian and Redwood Materials are giving used EV packs a second job inside the auto industry itself. The companies announced on April 14, 2026, that more than 100 second-life Rivian battery packs will be integrated into a 10 MWh stationary storage system at Rivian's manufacturing plant in Normal, Illinois. The first use case is practical: shave peak demand, lower energy costs, and make factory power more flexible. 10 MWh Initial storage capacity 100+ Rivian EV packs reused Normal, IL Factory site for the system From warranty pack to grid asset The packs in the project come from sources such as warranty returns, test vehicles, and early high-mileage fleets. Those batteries may no longer be ideal for an electric truck or SUV, where weight, range, packaging, and customer confidence are strict. But many still hold enough usable capacity to work in a stationary system, especially when software can manage differences in age, chemistry, and state of health. That is Redwood's role. Its Redwood Energy business integrates the packs and uses Redwood Pack Manager software to operate them as one dispatchable resource. The software has to do more than turn packs on and off. It must track capacity, temperature, voltage behavior, degradation, safety limits, and available power across packs that did not all live the same first life. The result is a storage system made from assets that might otherwise move directly into recycling. Recycling remains critical, and Redwood is best known for recovering battery materials. But a pack that can serve several more years in stationary storage before recycling can extract more economic value and reduce the need for new cells in some applications. Why put second-life batteries at a factory? Manufacturing plants are good hosts for batteries because their power bills are shaped by peaks. A short period of high demand can increase monthly charges. A battery can discharge during those peaks, reducing the plant's demand from the grid. That is peak shaving, and it is one of the most reliable business cases for behind-the-meter storage. The system can also help Rivian manage operational resilience. It is not a replacement for the grid, and 10 MWh is small compared with the energy needs of a major auto plant. But it can smooth short spikes, support critical loads, and help the site respond to utility signals. If paired with on-site solar or future power purchase arrangements, it could also shift lower-cost energy into higher-cost hours. There is symbolic value too, but the economics matter more. A second-life battery project located at the same company that produced the packs creates a cleaner loop. Rivian gets a use for returned or aged packs. Redwood gets a live operating case for heterogeneous battery management. The factory gets a power asset. The final recycling stream remains available later. Key Insight Second-life storage only works if software can turn uneven packs into a predictable asset. Redwood is trying to make that integration layer the business, not just the recycling step. A test of the second-life promise The battery industry has talked about second-life EV packs for years. The logic is appealing. Vehicle packs often retain a meaningful share of their capacity after they are removed from cars. Stationary systems do not need the same energy density. Reuse could lower costs, reduce waste, and create a bridge before materials are recycled. The hard parts are less glamorous. Used packs vary widely. They come from different model years, climates, charging habits, accidents, warranty histories, and software versions. Testing takes time. Pack disassembly and recertification can be expensive. Safety rules are still evolving. If labor and diagnostics cost too much, a new LFP storage system may be cheaper and easier to finance. That is why this Rivian project is useful. It keeps the pack population relatively controlled because the batteries come from one automaker's ecosystem. It places the system at an industrial site with a clear energy use case. It gives Redwood operating data. It does not ask second-life batteries to compete immediately in every utility-scale procurement against brand-new containers with standardized warranties. Redwood's broader storage move Redwood is expanding beyond the image of a pure recycler. The company has announced battery materials work, recycling partnerships, and energy storage projects, including a 63 MWh microgrid project in Nevada and relationships with major automakers. The Rivian system fits that strategy because it connects collection, diagnostics, reuse, and eventual recycling in one chain. For automakers, that chain could become important as EV fleets age. More battery packs will leave vehicles through warranty claims, crashes, fleet retirements, and upgrades. Companies need defensible answers for what happens next. Direct recycling will be right for damaged or badly degraded packs. Second-life storage may be right for packs that still have enough usable capacity and can be integrated safely. The project also arrives as US storage demand is rising fast. Grid batteries, commercial systems, and industrial backup assets all need cells. If second-life batteries can cover even a small slice of that demand, they can reduce pressure on new manufacturing and provide another revenue stream for EV makers. Pack design will influence how far this model can go. Batteries that are easier to diagnose, remove, transport, and reconnect will have better second-life economics. Automakers that plan for reuse at the design stage may recover more value than companies that treat end-of-vehicle life as an afterthought. Fleet operators will be watching closely because their vehicles create predictable battery retirement streams. That predictability can turn a messy reuse market into planned inventory. Factory power is a sensible first market The Normal project is not the end state for second-life batteries. It is a controlled proving ground. If Redwood can show reliable operation, clear safety management, and real bill savings, the model can scale to more factories, warehouses, charging depots, and microgrids. If the system underperforms, that will be useful too, because it will show where diagnostics, warranties, or pack design need improvement. For now, Rivian and Redwood have made the second-life story more concrete. Used EV batteries are not just a future recycling feedstock. In the right setting, they can become factory infrastructure.