141 



Question 6: What is BPA's latest estimate of the annual costs for a drawdown of this four 

 Lower Snake River dams ([i e.] the "Idaho Plan")? Please use the definition of 

 drawdown used in the Huppert Report and include the appropriate dam 

 modification costs released by the Army Corps of Engineers earlier this year. 

 Please provide a breakdown for the various components such as firm power, 

 secondary power, etc. 



Answer; BPA has not conducted an independent analysis of this four Lower Snake 



River draw down However, the Corps 1992 Options Analysis EIS looks 

 at a draw down scenario similar to that in the Huppert Report. The Idaho 

 Plan analyzed in the EIS calls for the four lower Snake projects to be 

 operated at near spillway crest from April 15 through June IS Drawdown 

 is to occur April 1-15 and refill by early July. Annual cost for lost firm 

 energy is estimated to be $72 million per year and lost firm capacity is 

 $32 million per year. Lost non-firm is estimated to range fi"om 

 $21 - $55 million per year Total annual losses for this plan of operation 

 are estimated to be in the range of $125 to $159 million. The Huppert 

 Report defines a different drawdown period. It would begin the draft on 

 April 7 to be near spillway crest in 2 weeks (April 21) and refill would take 

 16 days to be completed by June 15. This operation was analyzed two 

 ways in an attempt to provide a minimum and maximum impact. As 

 reported by the Corps, costs to make modifications are fi-om $1 .3 to $4.9 

 billion. 



The estimated annual capital costs for the four lower Snake projects based on 

 amortizing the modification costs of $1 .3 - $4.9 billion over 50 years at a 

 7.25 percent Treasury borrowing rate is $97 - $366 million. Combining the 

 annual capital cost of $97 - $366 million with the annual operating costs of 



