This bill amends existing Washington law (RCW 19.405.020 and RCW 19.405.030) relating to wholesale power purchases under the Clean Energy Transformation Act. It revises numerous definitions (including "coal-fired resource," "biomass energy," "allocation of electricity," and several renewable and retail customer definitions) and explicitly adds three exclusions to the definition of "coal-fired resource": short-term wholesale purchases for delivery to Washington retail customers (contracts up to three months, or system sales up to six months when needed for seasonal resource adequacy), electric generating facilities subject to RCW 80.80.040(3)(c), and electricity purchased from the Bonneville Power Administration under long-term agreements except for any portions known at the time to come from coal-fired units. The amendment to RCW 19.405.030 requires each electric utility to eliminate coal-fired resources from its allocation of electricity by December 31, 2025 (excluding costs for decommissioning and remediation). It directs the Washington utilities and transportation commission to allow in rates prudently incurred decommissioning and remediation costs for investor-owned utilities, to accelerate depreciation schedules for coal-fired resources to no later than December 31, 2025, and to permit accelerated depreciation for certain high-voltage transmission lines tied to coal generation when they are no longer used and useful. The commission must also allow in rates prudently incurred undepreciated investment in a fossil fuel generating resource retired for enumerated reasons or when retirement is found to be in the public interest. Utilities that fail to meet the December 31, 2025 elimination requirement are subject to the administrative penalty under RCW 19.405.090(1), and the section expressly allows purchases or exchanges from the Bonneville Power Administration. The bill also defines several terms (including "qualified transmission line," "renewable energy credit," "renewable hydrogen," "renewable natural gas," "renewable resource," "retail electric customer," and "retail electric load") and references agency roles for the department, the commission, the attorney general, and the state auditor. Some text is missing from the extracted material (the remainder of the "nonpower attributes" exclusion and potentially other definition text, and any other amendments elsewhere in the chapter), so the summary does not include provisions not present in the provided extracts.

If enacted, utilities will have to stop counting coal-fired generation as part of their Washington retail electricity supply by December 31, 2025, which will push owners of coal plants and utilities to retire, replace, or offset that output quickly. Investor-owned utilities are likely to see the biggest near-term financial effects: regulators must accelerate depreciation for coal plants (and in some cases high-voltage transmission lines tied to those plants) so their book value is written down by the 2025 date, and the commission will allow recovery in rates of prudently incurred decommissioning and remediation costs and certain undepreciated investments retired for specified reasons. The law also preserves short-term buying options (very short contracts or seasonal system sales) and continued purchases from the Bonneville Power Administration in most cases, which gives utilities some flexibility to meet seasonal resource needs while complying. It is unclear from the provided text how penalties will be calculated or how consumer-owned utilities will recover retirement costs compared with investor-owned utilities, and portions of several definitions are missing, so some operational details and enforcement mechanics remain uncertain.