RECAP: Renewable Energy Capacity Planning Model

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The E3 Renewable Energy Capacity Planning model (RECAP) assesses generation resource adequacy for a power system based on loss-of-load probability analysis. We developed RECAP in 2011 to meet system reliability planning needs under high renewable penetration, and have used it to help many utilities in a variety of situations.

  • We applied RECAP to calculate reliability metrics such as loss-of-load probability, loss-of-load expectation, expected unserved energy, and effective load-carrying capability (ELCC) on behalf of both the California ISO and the Western Electric Coordinating Council to support their reliability assurance missions.
  • For Oregon’s Portland General Electric (PGE), a utility with 3,600 MW peak demand, we calculated a planning reserve margin (PRM) that meets a 1-day-in-10-year generation reliability standard. We used the 15.3 percent PRM to determine capacity needs in PGE’s 2016 integrated resource plan. E3 also determined the effective load-carrying capability (ELCC) for PGE’s existing fleet of wind resources and for combinations of new wind and solar resources under consideration.
  • We used RECAP to calculate the ELCC of new and existing renewable resources as well as demand response programs for the Sacramento Municipal Utilities District. The results of our studies are used in the district’s integrated resource planning process to help estimate the need for new capacity resources.



RECAP demonstrated that as more solar generation is added to a power system its incremental capacity contribution declines. LEFT: Daily net load. RIGHT: Effective peak load reduction LEFT: Daily net load. RIGHT: Effective peak load reduction

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