What Is Interchange:

One of the greatest benefits of the Western Interconnection is its geographic diversity as it relates to demand and resources. When one part of the interconnection is experiencing peak demands, other areas may not be. While resources may not be available in one subregion due to weather, fuel, etc., other subregions may have plenty of resource availability. It is important in evaluating resource adequacy to consider each subregion's ability to import energy from other subregions to cover the hourly risk in its system.

Page Tips:

By selecting separate regions from the map, you can see specific trends associated with the different sub-regions within the Western Interconnection. Different combinations of BAs can be selected from the drop-down chart.

Note: When a sub-region is selected from the map, the list of BAs in the drop-down list corresponds to the BAs in that region. If there are selections in the BA list, only the regions of the map with a BA in the list are selectable.

To reset the map, select the highlighted region a second time. To reset the BA list, either “x out” of the BA(s) selected or hit the eraser button.

Click on the arrows connecting sub-regions to see the distribution of power flows between those sub-regions in each quarter over several years.

Histograms portray the historical frequency of exchange flows between sub-regions for different quarters of the calendar year. Positive values correspond to flow in the direction indicated by the label on the x-axis. Negative values correspond to flows in the opposite direction.