Everyone understands that storage will play an important role in the energy transition, as we move from conventional thermal power plants that can be dispatched at will to energy systems predominantly supplied by variable renewables. But important questions remain: how much storage will be needed? What type of storage is best? When will storage be most important? There hasn’t been a lot of great scholarship on these practical implications for deploying storage across the grid so far, but a multi-year project called the Storage Futures Study that was just completed by researchers at the National Renewable Energy Laboratory (NREL) advances the literature considerably. The seven component reports of the Storage Futures Study explore when and where a range of storage technologies are cost-competitive, depending on how they're operated and what services they provide for the grid, as well as the role and impact of relevant and emerging energy storage technologies in the US power sector a...