This article discusses the upcoming changes in the electricity industry including electrification, and the drive toward fossil-free generation, and the role of energy storage (ES) in electrification and the operation of a future electric grid without fossil fuels. Though our discussion is primarily focused on the United States electricity system, the issues affecting the operation of future electric grids are global. While the United States is prototypical of other highly developed and energy-intensive countries, variations in renewable energy production and storage, end energy usage, market structure, and policy, among other factors, make each country somewhat unique.