On page 18, after line 15, insert the following:
"(2)(a) The department of commerce must adopt a rule to establish a methodology for determining emission reductions attributable to modifications to the state energy code for residential structures. The department of commerce must provide a ninety-day public comment period prior to adopting the methodology.
(b) Using the methodology adopted under (a) of this subsection, the department of commerce must estimate a baseline of emissions associated with residential buildings constructed under the 2015 energy code for residential structures, and must estimate the amount of emission reductions relative to the baseline anticipated to be achieved during a three-year implementation period of the 2018 energy code for residential structures.
(c) The 2018 energy code for residential structures must not be implemented if estimated emission reductions under the 2018 energy code for residential structures relative to the 2015 energy code for residential energy structures exceed the percentage rate of emission reductions required on an annual basis in order for Washington state emissions to achieve the limits established in RCW
70.235.020. Instead, the 2018 energy code for residential structures must be revised to achieve emission reductions that are consistent with the annual emission reductions from new residential construction that would be needed to achieve the limits established in RCW
70.235.020.
(3)(a) The department of commerce must produce an economic analysis of the cost per ton of greenhouse gas emission reductions of any projected emission reductions anticipated to be achieved during the three-year implementation period of the 2018 energy code for residential structures. This analysis must model expected greenhouse gas emission reductions from a variety of new residential construction types and sizes of home in each climate zone in Washington over the life of the home, considering the fuel mix likely to serve those homes for electricity and heat. The analysis must describe the upfront cost added to new residential construction as a result of the 2018 energy code for residential structures.
(b) The 2018 energy code for residential structures may not be implemented if the department of commerce determines that the cost per metric ton of greenhouse gas emission reductions from the 2018 energy code for residential structures is greater than the cost of emission reductions through the purchase of other regulatory instruments that represent verifiable emission reductions."