Power system reliability modeling is important to wind integration studies, particularly given the potential for long periods of low wind and the need to accurately compensate wind plants for their contribution to system adequacy. Regarding the computation of capacity credits for wind, most of the studies used some variant of the ELCC method from Keane and colleagues (2011), but with only 2 or 3 years of data. As suggested in Hasche and colleagues (2011), accurate estimates of ELCC require 5 or more years of data because substantial interannual variations in wind resources are possible. Going forward, capacity credit calculations in wind integration studies should be based on at least 5 years of wind data.
A majority of the studies reviewed used GE MARS for reliability modeling. While this tool is useful for generation adequacy assessment, reliability is a function of both generation and transmission. The transmission network models used in GE MARS do not capture the physics of actual power flows, which can be very important to reliability. The methodology for composite generation and transmission reliability modeling is relatively mature in the research literature, with specialized methods available specifically for wind integration studies (e. g., Billinton, Yi, & Karki, 2009). We suggest that future wind integration studies incorporate composite system adequacy assessment methods with at least DC transmission system models in order to provide more useful insight into the reliability effects of large-scale wind integration. This will be particularly important in studies that estimate the effect of power-plant retirement and transmission system overlays, since both of these can have important reliability effects.
