2009 State of the Market Report
markets over wide geographic areas, is one of the most significant Midwest ISO interfaces. Accordingly, Figure 90 shows the average net imports scheduled for the Midwest ISO-PJM interface in each hour of the day.
Figure 90: Hourly Average Real-Time Net Imports from PJM 2009
Average Net Imports
Standard Deviation of Net Imports
Net Imports (MW)
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Hour Ending
Midwest ISO is a net importer of power from PJM during each hour of the day. More imports are scheduled during peak hours than off-peak hours. The fluctuation in hourly net imports is less pronounced in 2009 than it was in 2008. In 2008, the Midwest ISO imported comparatively less during morning hours and more during afternoon and evening hours.
The standard deviation of the net imports declined in 2009 compared to 2008. However, it remains large, indicating that the magnitude and direction of the flows between the two markets is highly variable. This is due to the similarity of the generating resources in PJM and the Midwest ISO. Hence, the prices in the two areas tend to move in similar ranges. Because the relative prices in the two areas govern the net interchange between them, movements in these prices will cause the incentives to import or export to oscillate.