2009 State of the Market Report
Real-Time Congestion Costs
Figure 49 shows the total congestion costs incurred in the day-ahead and real-time markets from 2007 through 2009.
Congestion Cost ($ Millions)
Figure 49: Total Congestion Costs 2007 – 2009
DA Congestion Cost RT Congestion Cost
J F M A MJ J A S O N D J F MA M J J A S O N D J F M A M J J A S O N D
Day-ahead congestion costs declined by nearly $200 million (39 percent) in 2009 compared to 2008. This reduction was due to reduced natural gas prices (which lower redispatch costs), lower average load, and transmission improvements. Day-ahead congestion costs were higher in the last four months of the year as economic conditions improved and natural gas prices increased.
Real-time balancing congestion is congestion that settles based on real-time market results. Normally, one would expect the real-time-congestion costs to be minimal if modeling of the transmission system is consistent between the day-ahead and real-time markets. In other words, congestion costs collected in the real-time market occur only when the transmission limits decrease from those in the day-ahead market model or when loop flow increases from the levels