In accordance with California Public Utilities Commission (CPUC) Decision (D.) 03-07-029, effective July 10, 2003, Southern California Edison's (SCE) total energy rate is the sum of 1) Delivery Services component and 2) the Generation component.  The Generation component is further broken down into two components 1) Utility Retained Generation (URG) and 2) Department of Water Resources (DWR).  The Delivery Services component is applied to the total kWh consumed during the billing period.  However, the Generation components (i.e., URG and DWR) must be applied separately to a percentage of the total kWh consumed during the billing period.  This percentage of the total kWh is determined on a bill cycle basis and the sum of the two percentages will always equal 100%.

In order to compute the percentage of energy supplied by the DWR in any given billing period, SCE has developed a Weighted Average Daily DWR % Table and an Average Daily DWR % Table.  For bills with a billing period start date on or after 9/22/06, please use the new Weighted Average table.*  For bills with a billing period start date prior to 9/22/06, please use the "Average Daily" table.  

  Weighted Average Daily DWR % Table  Average Daily DWR % Table 

During each billing period the URG percentage is calculated by subtracting the DWR percentage from 100 percent.  The energy supplied by the DWR is roughly in the 30 percent range during any given billing period, which results in a URG energy supplied percentage of roughly 70.

Instructions:  To calculate the percentage portion of your energy usage (kWh) provided by the DWR during a specific timeframe, please refer to your SCE bill and find the end date of your billing period and number of days in that billing period.  The DWR % provided in the Average Daily DWR % Table is multiplied by total usage to provide the DWR kWh.  This Table will be updated weekly.

*The Weighted Average Daily DWR % Table is a new process for calculating the DWR percent of generation for billing purposes.  This process changes from calculating a simple average (Sum of Daily DWR % / number of bill days in billing cycle) to calculating a weighted average which is based on SCE's daily load (Sum of Daily DWR % multiplied by SCE's daily load / sum of daily loads over billing cycle).  This change is necessary due to a recent 2006 DWR Servicing Order.