308 



Investment cost, resulting In a total annualized capital and maintenance cost 

 of $129,688 million (Table A-2. line 8. column C>. However, this annual cost 

 overstates the benefits derived from the DSI restriction rights. In FY 1987, 

 the imount of reserves the DSIs can provide through restriction of the second 

 and third quartlles Is greater than the reserves required. The Investment 

 cost Is prorated based on the amount of reserves required In the test year to 

 the amount of generation Installed. Thus, the cost to provide forced outage 

 reserves in lieu of the DSI restriction rights Is $88,850 million (Table A-2. 

 line 10, column C). 



The valuation for forced outage reserves also includes the 

 operating costs associated with running the combined cycle combustion turbine 

 during the time that the OSIs would have been restricted. The results of SAM 

 show no expected restrictions of the DSIs for forced outages during the test 

 year. Thus, no fuel costs or operating costs associated with running the 

 combustion turbine for forced outages are included in this analysis. 



B. Stability Reserves 



After consideration of several proposed alternatives, BPA 

 determined in FY 1982 that a load tripping scheme was the least cost 

 alternative to the DSI restriction rights for providing stability reserves. 

 This alternative conforms with both the BPA Reliability Criteria for System 

 Planning and the Western System Coordinating Council Reliability Criteria for 



A-10 



