The first table in the results file for the ComEd Procurement Event, “Average Prices ($/MWh) and Quantities (MW) of Products and Combinations provides the average clearing price and the quantity procured for each product and for each Combination. A Combination is a grouping of two or more Products.
The second table, “Average Prices of Contracts”, provides the average price for each month of a given year and segment. The average price in the second table is the weighted average of (i) the average clearing price for the product corresponding to the month, segment and year in question and (ii) the average clearing price for each Combination procured that includes that product.
For example, the first table in the ComEd Procurement Event section provides a quantity of 450 MW and an average price of $48.40/MWh for July 2015 on-peak. However, energy for the on-peak segment of July 2015 was also procured through the Jul-Aug2015 on-peak Combination (800 MW and an average price of $44.05) and through the Jun2015-May2016 on-peak Combination (550 MW and a price of $38.58). Thus the second table provides a quantity of 1800 MW and an average price of $43.47.