Large- (i.e., utility-) scale stationary applications can be divided into two categories based on function. Energy Management applications use stored energy to decouple the timing of generation and consumption of electric energy. Power Management applications use stored energy to ensure continuity, quality, and proper frequency of delivered power in real time. In general energy applications involve (relatively) long-duration discharge and power applications involve short-duration discharge. The two application categories (energy or power) can be further refined based on how frequently the storage device is expected to be used (frequent use or infrequent use).
In general ‘long-duration’ storage (used for energy management applications) means a discharge duration of up to hours or more. Frequent discharge for long-duration storage implies almost daily use throughout the year. Infrequent discharge of long-duration storage implies discharge between one and two times per month over the course of a year. Actual frequency of use will depend on both the specific application and the specific needs the storage system is expected to meet.
Short-duration discharge (used for power management applications) can be any discharge from a few fractions of a second up to about fifteen minutes depending on the application. In general, frequent discharge of short-duration storage implies hundreds of discharges over the course of a year. Infrequent discharge of short-duration storage implies between one and two discharges per month averaged over the course of a year. Again, actual system use will vary with application and needs. The numbers provided are only intended to provide a general idea of the type of application being discussed.
Although certain storage technologies can be used for all of the applications, most technologies are not practical and/or economical for both power and energy applications. The table below shows the suitability of some of the more common technologies for various applications. These and other technologies are discussed in greater detail below. See the Applications menu in the top navigation bar for more information on specific power and energy management applications.