This legislation, titled the "Northwest Energy Security Act," directs the Secretaries of the Interior, Energy, and Army to operate the Federal Columbia River Power System (FCRPS) in a manner consistent with the reasonable and prudent alternative described in the September 2020 Columbia River System Operations Environmental Impact Statement Record of Decision , referred to as the Supplemental Opinion. The bill establishes a strict process for any deviations from this operating plan. Amendments to the Supplemental Opinion are permitted only if all three Secretaries determine, in their sole discretion, that such changes are necessary for public safety or transmission and grid reliability , or if the actions being removed are no longer warranted. This process is designated as the exclusive method for operating the FCRPS in any way inconsistent with the original Supplemental Opinion. A significant provision of the bill prohibits any structural modification, action, study, or engineering plan that would restrict electrical generation at any FCRPS hydroelectric dam or limit navigation on the Snake River in Washington, Oregon, or Idaho. Such actions can only proceed if specifically and expressly authorized by a new Federal statute enacted after this bill's passage. This limitation does not, however, affect the Secretaries' authority to conduct routine operation, maintenance, or capital improvements necessary for authorized project purposes of FCRPS facilities.