California ISO Five Year Assessment (2004-2008)

This report illustrates how a typical ISO might assess the capacity value of energy sources within an energy portfolio and the negligible capacity value accorded industrial wind. An excerot of the report discussing the limitations of wind is provided below. The full report can be accessed by clicking the links on the page.

Wind Limitations

Wind capacity is an important resource to serve load in the ISO Control Area, and it is anticipated that the amount of wind generation will continue to increase to meet the requirements of the IOUs’ recent Renewables Portfolio Standard. Because wind units are intermittent resources, it is difficult for these generators to participate in the ISO energy market. The ISO has recently introduced an elective program for intermittent resources that assists the ISO in real time dispatch and also protects wind generators from uninstructed deviation charges that can occur due to sporadic wind conditions. More information on the ISO Participating Intermittent Resource Program can be found at under Market Services.

Base Scenario

Summer: The forecast of the wind capacity attainable at peak is based on historical output during times of daily peak. Historically, wind speeds and wind generation output are lowest during the peak hours on hot summer days while almost all the wind units are inactive. Wind capacity is fully de-rated during the summer months because it is not dependable during the summer peak. 

Winter: There is little relationship between wind capacity and winter peak demand, thus the winter wind capacity forecast is based on average wind generation experienced during winter peaks (shown in Figure 10). The base forecast for wind generation during the winter months is 200 MW, which represents the level of wind generation that is available fifty percent of the time (shown in Figure 11).

Adverse Scenario

Wind is an intermittent resource during winter peaks with no relationship to peak day loads. At anytime wind speeds and wind generation output could be inactive. The Adverse scenario forecast during both summer and winter months is 0 MW. 

California Iso 2003 Discounting Of Wind Energy

Download file (441 KB) pdf

OCT 10 2003
back to top