Transmission evaluation of large new renewable generation interconnections at the california ISO

The CAISO has launched a Renewables Integration Study to assess the impact of renewable resources on the system. This study was initiated to determine if there are any performance related issues associated with the implementation of the Renewables Portfolio Standards (RPS). The RPS mandates utilities and other load serving entities to procure 20 percent of their customers´ electricity needs from renewable power by 2010. Meanwhile, many system impact studies have been performed by the CAISO for new wind generation interconnections submitted by developers. This paper outlines the studies that were done at the CAISO as part of the transmission planning process; the methodologies and assumptions to perform these studies; and a summary of the conclusions derived from the studies.