(1) An electrical company may account for and defer for later consideration by the commission costs incurred in connection with major projects in the electrical company's clean energy action plan pursuant to RCW
19.280.030(1)(l), or selected in the electrical company's solicitation of bids for delivering electric capacity, energy, capacity and energy, or conservation. The deferral in this subsection begins with the date on which the resource begins commercial operation or the effective date of the power purchase agreement and continues for a period not to exceed thirty-six months. However, if during such a period the electrical company files a general rate case or other proceeding for the recovery of such costs, deferral ends on the effective date of the final decision by the commission in such a proceeding. Creation of such a deferral account does not by itself determine the actual costs of the resource or power purchase agreement, whether recovery of any or all of these costs is appropriate, or other issues to be decided by the commission in a general rate case or other proceeding.
(2) The costs that an electrical company may account for and defer for later consideration by the commission pursuant to subsection (1) of this section include all operating and maintenance costs, depreciation, taxes, cost of capital associated with the applicable resource or the execution of a power purchase agreement. Such costs of capital include:
(a) The electrical company's authorized return on equity for any resource acquired or developed by the electrical company; or
(b) For the duration of a power purchase agreement, a rate of return of no less than the authorized cost of debt and no greater than the authorized rate of return of the electrical company, which would be multiplied by the operating expense incurred by the electrical company under the power purchase agreement.