(1) Costs incurred before June 9, 1994, by electrical, gas, or water companies with respect to energy or water conservation measures and services intended to improve the efficiency of energy or water end use shall constitute bondable conservation investment for purposes of RCW 80.28.005, 80.28.303, 80.28.306, and this section, if:

(a) The commission has previously issued a rate order authorizing the inclusion of such costs in rate base; and

(b) The commission authorizes the issuance of conservation bonds secured by conservation investment assets associated with such costs.

(2) If costs incurred before June 9, 1994, by electrical, gas, or water companies with respect to energy or water conservation measures intended to improve the efficiency of energy or water end use have not previously been considered by the commission for inclusion in rate base, an electrical, gas, or water company may apply to the commission for approval of such costs. If the commission finds that the expenditures are a bondable conservation investment, the commission shall by order designate such expenditures as bondable conservation investment, which shall be subject to RCW 80.28.005, 80.28.303, 80.28.306, and this section.