339 



requirements, thereby causing more hydropower to be available 

 during the summer, especially at night. 



The attached exhibit 3 roughly illustrates that the irrigation 

 load occurs during BPA's "off-peak" summer period and at a time of 

 high streeun flows when BPA generates greater amounts of energy from 

 hydropower. Although exhibit 3 shows only one year of operation of 

 the hydrosystem, it indicates that in the months June, July and 

 August, when the majority of irrigation load occurs, streamflows 

 and BPA's generation from streamflow reached their maximum. In 

 fact, generation from streamflow alone was sufficient to meet BPA's 

 estimated firm energy load in June and July and most of the load in 

 August . 



To illustrate that irrigation load occurs during BPA's "off- 

 peak" period, the monthly average of the Benton PUD irrigation load 

 is shown on Exhibit 3 as solid bars which peak in June, July and 

 August and decline to virtually nothing in the December, January 

 and February period. 



Having said that an irrigation discount, or equivalent rate is 

 justified based on BPA's cost to serve this summer only load, it 

 must be conceded that it is not possible to quantify that cost 

 differential at this time. It costs less, that much is certain; 

 however, as mentioned in my earlier comments on PMDAM, BPA's 

 methodology for allocating its costs to rates is in the preliminary 

 stages of being completely revised. Changing resource 

 requirements, the changing operation of the Federal System, 

 consideration of tiered rates, and many other factors make any 

 attempt to quantify the cost of serving summer only loads 

 premature. A great deal of analysis by BPA, NIU and other BPA 

 customers will be devoted to this issue prior to the 1995 BPA rate 

 case. 



A. Irrigation Load Occurs Exclusively During BPA's "Off- 

 Peak" Period. BPA's irrigation load is unique because it occurs 

 only in the summer during BPA's off peak period. ^ Because 

 irrigation is an exclusively off-peak load, it contributes nothing 

 to BPA's need for additional resources in the November through 

 February winter peak. As previously noted, BPA's winter peaks are 

 primarily responsible for BPA's need to invest in additional 



Irrigation usage occurs throughout the year approximately as follows: 



Novenber- -March O.U 



April 2.6X 



Hay 8.4X 



Juw 20.SX 



July 38.7X 



August 21. 2X 



Septenber 7.3X 



October 1.2X 



