E3: Energy+Environmental Economics
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Renewable Energy Capacity Planning (RECAP) Model

Download E3 RECAP model for CAISO here

Over the last several years E3 has developed tools that are now being implemented for analyzing bulk power system reliability and flexibility under high renewable penetration. RECAP is an easy-to-use, open-source bulk system reliability model that uses established reliability planning techniques for analyzing power system reliability. RECAP calculates standard reliability metrics such as loss of load probability (LOLP), loss of load expectation (LOLE) or Effective Load Carrying Capability (ELCC).

RECAP works by comparing probability distribution functions (PDFs) for supply and demand by month, hour, and day type (weekend, weekday) in order to find the probability that load will be greater than supply (LOLP). ELCC values for renewable resources represent the quantity of additional load that can be served by a renewable resource, expressed as a fraction of nameplate capacity. The chart below shows that ELCC of a solar PV resource can be quite high initially; however, as penetration increases, the effectiveness of adding more PV declines substantially.


RECAP was first developed through work with the California Independent System Operator (CAISO) to evaluate the need for system capacity in 33% RPS scenarios. E3 continues to use RECAP to support the CAISO's modeling of capacity and flexibility needs to accommodate high renewable penetration in the context of the California Public Utilities Commission's (CPUC) Long-Term Procurement Planning proceeding. E3 has also used RECAP to evaluate the effectiveness of dispatch-limited resources such as demand response on behalf of the CPUC and the Sacramento Municipal Utilities District, to analyze the effects of California's net energy metering policies, and to investigate the cost-effectiveness of the California Solar Initiative.