Monthly Generation System Peak (GSP) is the peak load (in MW) on the Federal System during a calendar month, determined by the largest hourly integrated demand produced from system generating plants in BPA's control area and scheduled imports for BPA's account from other control areas.

Effective with bills sent out November 1, 2001 (for the October 2001 billing period) for most customers, the GSP is the hour of the largest Heavy-Load Hour (HLH) output of the Federal System that occurs during the customer's billing period.  [See Item #19 on page 130 of the 2007 General Rate Schedule Provisions.]   However, the GSP for some Pre-Subscription customer bills will continue to be based on the Maximum (Max) Monthly GSP.

Typically the HLH GSP and the Max GSP occur at the same time during a month. Since they sometimes occur at different times, HLH GSP and Max GSP are provided in separate tables below.