Some Weird Things Are Happening And The Grid May Never Be The Same

Redwood Materials, founded by former Tesla CTO JB Straubel, is making significant strides in transforming the energy storage landscape by repurposing end-of-life electric vehicle batteries. Initially focused on sustainable battery recycling, the company pivoted in 2024 towards developing grid storage solutions, leveraging its expertise in battery materials and testing. Under the leadership of Nancy Sun, a power electronics specialist, Redwood launched a pilot project last summer to power data centres near Reno, Nevada, using a combination of solar power and repurposed batteries. This system demonstrated remarkable resilience during a severe blizzard in February, prompting plans to expand the technology to 20 additional data centres. The company’s approach involves reusing EV batteries that no longer meet the performance demands of vehicles but still retain significant energy capacity. Redwood’s innovation lies in its proprietary “pack manager” technology, which enables communication and control across batteries with varying voltages and conditions. This system balances the workload among battery packs, cycling older batteries more gently while utilising fresher ones more intensively, thereby maximising the lifespan and efficiency of the storage units. Redwood’s development process revealed the necessity of custom-built power electronics, controls, and software to manage these second-life batteries effectively. Cost efficiency is a key focus for Redwood, which has designed an open-air, low-density storage system that avoids the need for expensive cooling and complex mechanical components. By mounting battery packs on above-ground cable trays and eliminating moving parts like fans, the system is not only cheaper to build but also easier to maintain and inspect, especially after extreme weather events. With over one gigawatt-hour of batteries ready for deployment and plans to add five gigawatt-hours more this year, Redwood is scaling rapidly to meet growing demand from data centres and utilities seeking affordable, reliable energy storage solutions. Despite the abundance of battery supply, Redwood faces challenges in scaling due to rigorous safety qualification processes, such as the UL 9540A fire safety test. The company is developing a “qualification flywheel” to streamline testing and certification, aiming to accelerate the integration of diverse battery chemistries and formats into their systems. This effort could significantly reduce the time required to bring new batteries online, shifting the bottleneck from supply constraints to regulatory and safety approvals. In a related development, the Minnesota Public Utilities Commission recently approved a plan by Xcel Energy to create a utility-owned virtual power plant (VPP), marking a shift from the traditional model of privately owned energy storage. This initiative will deploy energy storage nodes at critical points on the grid to manage peak demand more effectively. Together, these advancements reflect a broader transformation in how energy storage and grid management are evolving, with repurposed EV batteries playing an increasingly central role.