Resource adequacy is a reliability requirement which ensures that there are sufficient generation and non-generation resources available to meet the forecast peak load along with reserve requirements, generally one to three years ahead. In California, to qualify for system or local area resource adequacy, a storage resource is rated at the maximum output which can be sustained for at least four consecutive hours and be available for at least three consecutive days.
This service constraints the DERs to provide power during system load peaks, which may not fully capture RA requirements in all locations. Grid stress does not necessarily always align with peak load and some places have a 'must offer obligation' where an offer for energy in the energy market is required instead of actual power.
|RA||days||This is the number of peak events (max one event per day) that will be identified by the resource adequacy service, as prescribed by the dispmode input.|
|RA||length||This is continuous energy requirement to provide resource adequacy. Commonly four hours.|
|RA||dispmode||If dispmode is 0, then the DER mix’s energy capability will be constrained so that it could fulfill RA length hours of generation during the identified peak system load events but is never actually called to do so.
If dispmode is 1, the generation power of the DER mix will be constrained so that it is providing power during the identified system load peaks.
The key assumption for resource adequacy when dispmode=1 is that the DER mix has knowledge of its need to participate far enough in advance. This allows the storage system to ensure it has enough state of energy at the beginning of an event to discharge at its qualifying capacity for the entire duration of the event. If these events were to happen with little notice, this condition might be violated based on the other objectives of the storage system.
Peak Identification Mode
|RA||idmode||This option allows for three different methods to identify peaks in the system load where the DERs will be required to discharge/generate power to meet their resource adequacy requirements.
Peak by Year - Identify the top days in a year to require power to fulfill resource adequacy requirements.
Peak by Month - Identify the top days in each month of the year.
|RA||growth||This input grows the RA Capacity Price monthly input every year.|
The RA service calculates the qualifying capacity of each DER based on its power capacity and continuous energy delivery potential. The continuous energy delivery potential is compared to the duration of energy storage systems and only the power capacity that can be delivered for the RA event length input is considered 'qualifying capacity'.
When active, the RA service imposes time series power constraints on the DERs during RA events.