1. (1) Each utility must document its calculation of the levelized annual incremental cost of eligible renewable resources. Utilities are encouraged, but not obligated, to use the following methodology:

   Step 1: Calculate the net present value of the cost of the utility's eligible renewable resource and substitute resource over an equivalent contract length or facility life.

   Step 2: Calculate equal nominal values over the appropriate contract length or facility life that have a net present value equal to those calculated in Step 1, using the same discount rate.

   Step 3: Calculate the annual difference between the levelized delivered cost for the eligible renewable resource and the substitute resource to determine the levelized incremental cost of the eligible renewable resource.

   A utility that uses the annual update methodology must document the basis for any change to the levelization methodology used in a prior June 1 report to levelize the costs of an eligible renewable resource and its associated substitute resource.

2. (2) Regardless of the methodology chosen to levelize costs, utilities must document the basis for their chosen method for levelizing costs.
3. (3) Utilities must document the basis for the discount rate used in its levelized cost calculations.
4. (4) Utilities must document how the discount rate used to perform the levelized cost calculations is consistent with the inflationary assumptions incorporated into the delivered cost projections for the eligible renewable resource and substitute resource.
5. (5) Utilities must document how the method and assumptions used to levelize delivered costs for the eligible renewable resource are consistent with those used to levelize the delivered cost of the associated substitute resource.

[Statutory Authority: RCW 19.285.080(2). WSR 08-07-079, § 194-37-170, filed 3/18/08, effective 4/18/08.]