Washington Revised Code Title 19. Business Regulations--Miscellaneous § 19.285.050. Resource costs

(1)(a) A qualifying utility shall be considered in compliance with an annual target created in RCW 19.285.040(2) for a given year if the utility invested four percent of its total annual retail revenue requirement on the incremental costs of eligible renewable resources, the cost of renewable energy credits, or a combination of both, but a utility may elect to invest more than this amount.

(b) The incremental cost of an eligible renewable resource is calculated as the difference between the levelized delivered cost of the eligible renewable resource, regardless of ownership, compared to the levelized delivered cost of an equivalent amount of reasonably available substitute resources that do not qualify as eligible renewable resources, where the resources being compared have the same contract length or facility life.