Maintaining reliability is increasingly challenging for electric grids as they endure more frequent extreme weather events and utilize more intermittent generation. Exploration of alternative reliability approaches is needed to effectively address these emerging issues. Here we examine the potential to use the US rail system as a nationwide backup transmission grid over which containerized batteries, or rail-based mobile energy storage (RMES), are shared among regions to meet demand peaks, relieve transmission congestion and increase resilience. We find that RMES is a feasible reliability solution for low-frequency, high-impact events and quantify its cost effectiveness relative to reliability-driven investments in transmission infrastructure and stationary capacity. Compared to new transmission lines and stationary battery capacity, deploying RMES for such events could save the power sector upwards of US$300 per kW-year and US$85 per kW-year, respectively. While no known technical barriers exclude RMES from grid participation, addressing interconnection challenges and revising regulatory frameworks is necessary for deployment at scale.

Maintaining reliability is a key challenge for electric grids as they endure more frequent extreme weather and utilize larger amounts of variable renewable energy in response to the climate threat. With traditional reliability approaches becoming less viable, alternatives are being sought. We examine using the U.S. rail system as a kind of nationwide backup grid, in which containerized batteries, or rail-based mobile energy storage (RMES), are shared among regions to meet demand peaks, improve resilience, and relieve transmission congestion. Such an approach could also accelerate decarbonization of the rail sector. We find that RMES is a feasible reliability solution and quantify its cost-effectiveness relative to reliability-driven investments in stationary storage and transmission infrastructure. While no technical barriers exclude mobile storage from electricity markets, addressing interconnection and cost challenges and revising regulatory frameworks will be needed to deploy it at scale.