Defining and Scouting Long-duration Energy Storage: Because “More Than Four Hours” Isn’t Enough

Greater penetrations of wind and solar capacity on the grid demand longer duration energy storage, but determining appropriate technologies remains difficult due to the wide range of requirements demanded by new energy storage applications. For utilities, this creates challenges specifying suppliers; for investors, it can make promising targets harder to identify. This report characterizes these new applications requiring long duration storage and finds the leading technologies and companies poised to succeed in this new landscape. We further describe the future opportunities for long-duration storage technologies in an evolving energy paradigm.