Energy storage capacity loss ratio

What is the capacity value of energy storage?

The capacity value of energy storage is dependent on the volume of renewable capacity in the system. The following tables summarize the projected wind and solar capacity and energy in the CAISO system in 2022. These amounts were derived from resource portfolios being developed in the CPUC’s IRP process as of November 2019.

How is energy storage capacity calculated?

The energy storage capacity, E, is calculated using the efficiency calculated above to represent energy losses in the BESS itself. This is an approximation since actual battery efficiency will depend on operating parameters such as charge/discharge rate (Amps) and temperature.

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

Rated power capacity is the total possible instantaneous discharge capability of a battery energy storage system (BESS), or the maximum rate of discharge it can achieve starting from a fully charged state. Storage duration, on the other hand, is the amount of time the BESS can discharge at its power capacity before depleting its energy capacity.

How will CAISO's energy storage capacity change in 2022?

The first 7,500 MWs of the 4-hour resources on the 2022 system are able to serve the shorter periods of elevated load but as the amount of energy storage resources on CAISO’s system is increased, the net load shape flattens. The incremental energy storage resources are then expected to serve longer periods leading to a diminished capacity value.

What is the relationship between solar resources and energy storage capacity?

Namely: There is a strong positive relationship between the penetration of solar resources and the capacity value of energy storage. At low penetrations of solar, capacity contributions from storage are relatively low (2,000 – 4,000 MW) but at high penetrations, the capacity value grows substantially (6,000 – 8,000 MW).

Does solar generation affect energy storage capacity value?

This effect means that the level of solar generation on the system can strongly impact the opportunity for limited duration energy storage resources to provide capacity, whereas the impact of wind penetration on storage capacity value will be more limited.