WA HB1679

Adds "advanced nuclear reactor" as a defined term in Washington's Clean Energy Transformation Act, meaning nuclear fission reactors with significant safety and efficiency improvements compared to reactors operating as of December 27, 2020

Allows electric utilities to count investments in advanced nuclear reactor projects as an alternative compliance option (up to 20%) toward the state's greenhouse gas neutrality requirements through December 31, 2044

Expands utility investment requirements to include nuclear energy resources alongside renewable resources and energy storage when acquiring new resources after May 7, 2019

Permits utilities participating in joint operating agency nuclear projects (not just members) to claim compliance credit proportional to their investment share

Requires the Department of Commerce to adopt rules for verifying advanced nuclear reactor project eligibility and determining how investments are measured for compliance purposes