What is the difference between energy storage duration and discharge rate?

For some technologies, the energy available may be proportional to the discharge rate and temperature (higher discharge rates typically allow less energy to be removed from the battery). Storage duration is the amount of time the energy storage can discharge at the system power capacity before depleting its energy capacity.

What is an energy storage system battery?

Like a common household battery, an energy storage system battery has a “duration” of time that it can sustain its power output at maximum use. The capacity of the battery is the total amount of energy it holds and can discharge.

How long does a battery storage system last?

For example, a battery with 1 MW of power capacity and 4 MWh of usable energy capacity will have a storage duration of four hours. Cycle life/lifetime is the amount of time or cycles a battery storage system can provide regular charging and discharging before failure or significant degradation.

What is the difference between rated power capacity and storage duration?

Rated power capacity is the total possible instantaneous discharge capability (in kilowatts [kW] or megawatts [MW]) of the BESS, or the maximum rate of discharge that the BESS can achieve, starting from a fully charged state. Storage duration is the amount of time storage can discharge at its power capacity before depleting its energy capacity.

How long can a battery be discharged?

Maximum 30-sec Discharge Pulse Current –The maximum current at which the battery can be discharged for pulses of up to 30 seconds. This limit is usually defined by the battery manufacturer in order to prevent excessive discharge rates that would damage the battery or reduce its capacity.

Can energy storage be used for a long duration?

If the grid has a very high load for eight hours and the storage only has a 6-hour duration, the storage system cannot be at full capacity for eight hours. So, its ELCC and its contribution will only be a fraction of its rated power capacity. An energy storage system capable of serving long durations could be used for short durations, too.