6. Scenario Results

The results of the scenario analysis are summarized in Tables 1 and 2 appended to this decision. Table 1 presents the results for all cases generated under the Joint Parties' Planning Scenario (Scenario 1), which assumes no generation retirements throughout the 2001-2011 planning period. Table 2 presents the results for scenarios that assume retirements during the planning period and a higher level of outages than the Joint Parties' Planning Scenario (Scenarios 2 and 5). Both tables also show the results of Scenarios 3 and 4, which remove transmission derating for selected cases. (See above.)

6.1 No Generation Retirements (Joint Parties' Planning Scenario)

A total of 48 cases were run under the Joint Parties' Planning Scenario to reflect various sets of assumptions concerning load, in-state ("internal") generation, and the availability of out-of-state ("external") generation resources for import. As indicated in Figure 1, 10 out of the 48 cases indicate a need for new transmission to the Southwest before the end of the planning period to maintain system reliability.

Specifically, transmission is needed under six cases that assume very low internal generation, i.e., that only 720 MW of new in-state generation will materialize over the planning period. Under the base load forecast, in the very low in-state generation case, additional transmission access to the Southwest is needed by 2008 for both the maximum and medium cases regarding available external resources. If the base load forecast is increased by10%, additional transmission import capability is required by 2005. If it is increased by 20%, then additional transmission is needed throughout the planning period. Transmission is also needed under the "low" and "medium" internal generation cases if the base load forecast is increased by 20%.

6.2 Retirements and Additional Outages Scenarios

Another 48 cases were run under Scenario 2, using the CEC's alternate assumptions concerning retirements and outages. As indicated in Table 2 and Figure 2, 16 out of the 48 cases indicate a need for increased import capability during the planning period. Figure 2 also illustrates that for two of these cases, there is insufficient external resources for import to meet all of the load demand within California, even under assumptions of "maximum" external resources.

Transmission is needed under all cases that assume very low internal generation, with the exception of the very lowest load assumptions (base load less 20% or average load). Transmission is also needed during the planning period under low and medium internal generation cases with base load plus 10% and 20%.

As discussed above, Scenario 2 assumes no retirements after 2003. If CEC assumptions concerning post-2003 retirements are used (Scenario 5), then the need for transmission is moved up 1-2 years in most of these 16 cases. (See Table 2.)

6.3 No Derating of Transmission Capability

The ALJ requested that Joint Parties produce the matrix spreadsheet results without derating transmission capability. As discussed above, transmission capability was derated for cases that assumed very low new in-state generation (720 MW) and a baseload, baseload plus 10% or baseload plus 20% load forecast. When derating is removed from these cases, the matrix results show a need for new transmission line generally 2-3 years later than the matrix results with derating. (See Tables 1 and 2.)