(1) The social cost of greenhouse gas emissions to be included by utilities in resource planning, evaluation, and selection, in compliance with RCW 19.280.030(3), is equal to the cost per metric ton of carbon dioxide equivalent emissions, using the 2.5 percent discount rate, listed in table 2, technical support document: Technical update of the social cost of carbon for regulatory impact analysis under Executive Order No. 12866, published by the interagency working group on social cost of greenhouse gases of the United States government, August 2016, referred to in this rule as the "technical support document."

(2) The social cost values for intermediate years are calculated by linear interpolation and provided in Appendix A of the technical support document. Social cost values for years after 2050 must be determined by applying an escalation factor of 1.3 percent, consistent with Table 3 of the technical support document. Social cost values must be adjusted for inflation, using the implicit price deflator for gross domestic product published by the United States Department of Commerce, from the 2007 dollars to the base year used for other cost and benefit values in the utility's analysis.

(3) As a convenience and illustration, the cost values established in subsection (1) of this section and adjusted as provided for in subsection (2) of this section for inflation to 2018 dollars are restated here:

(4) The social cost values established in this rule are minimum values. A utility may apply a greater value if it has a reasonable basis to do so.