Home battery systems can help during power outages. So can the battery packs rolling around in electric vehicles. Last month’s preventative power shutoffs in California highlighted the vulnerability of the electricity grid to threats exacerbated by a changing climate. In the wake of the forced outages, much has been written about the ability of solar PV arrays working in tandem with stationary battery storage systems to keep the lights on when the grid goes down. But what about the mobile battery packs carried in the hundreds of thousands of electric vehicles now on the road in California?