April 27, 2023
Action Date
Information Only
Legal & Regulatory
Washington WEIM Greenhouse Gas Enhancements: Notice of expected activation

The California ISO is activating the functionality for the Washington WEIM Greenhouse Gas (GHG) Enhancements project on May 1, 2023. The Washington WEIM GHG Enhancements initiative is intended to improve market efficiency by allowing SCs subject to Washington state’s GHG program to reflect their GHG compliance cost in their resource bids. It does so by including the GHG costs in these resources’ default energy bids and default commitment costs (minimum load costs and startup costs).


The functionality being introduced on May 1, 2023 will be an interim alternative approach until the full functionality can be deployed. The full functionality is expected to be deployed as part of the Fall 2023 release. The implementation of the interim alternative approach is not expected to impact the timeline or scope of the full functionality.


The interim alternative approach leverages existing CAISO market functionality to comply with the FERC-approved tariff provisions related to this initiative. California ISO will publish business practice manual (BPM) edits describing the details of the interim alternative approach. These will be available on the BPM Change Management page.


For questions regarding the activation of the interim alternative solution, please submit these via the Customer Inquiry, Dispute, and Information (CIDI) system. These questions should be submitted as a CIDI Inquiry ticket with a title of “WA GHG Enhancements”.


Please contact ISO Stakeholder affairs at or through CIDI ticket for any questions.

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