GHG Tracking Report for California ISO Load Finalized; Companion EIM Report Postponed for Additional Data
The California ISO has finalized its California Greenhouse Gas Tracking Report, providing data on GHG emissions from energy resources dispatched on the ISO grid and imported to serve ISO load. The ISO has postponed a companion report planned to track GHG emissions associated with service of ISO load using the western Energy Imbalance Market (EIM) to refine its methodology.
The California ISO has finalized its California Greenhouse Gas Tracking Report, providing data on GHG emissions from energy resources dispatched on the ISO’s grid and imported to serve ISO load. The report, finalized by the ISO following public input, will be updated monthly and made available on the ISO’s website.
The ISO has postponed a companion report planned to track GHG emissions associated with serving ISO load using the western Energy Imbalance Market (EIM) while it works to enhance the EIM GHG attribution methodology.
An initial draft proposal and preliminary methodology paper for both the California and the EIM models was released by the ISO in early November, followed by a public stakeholder teleconference. After reviewing stakeholder input, and considering the related input in the stakeholder process to develop enhancements to the GHG attribution methodology for EIM, the ISO recognizes the EIM report needs additional data to provide a more accurate GHG accounting associated with serving ISO load using EIM.
The ISO’s preliminary methodology in the EIM assessment used a counterfactual analysis to approximate a dispatch model without EIM transfers between all EIM balancing areas and then compared GHG emissions with the EIM dispatch. The ISO, however, now recognizes this approach does not sufficiently assess whether inter-EIM area transfers external to California would have economically occurred regardless of the load served in California using EIM.
Furthermore, the counterfactual analysis cannot determine if the emissions observed are a result of optimized transfers between balancing authority areas outside of California and therefore serving load outside of California, or transfers from those areas to serve load in the California ISO.
To remedy this, the ISO is proposing to develop enhancements to run its least-cost dispatch and GHG attribution process in two steps:
Identify the least-cost dispatch of resources to serve EIM load without transfers to serve California load; and
Re-run the least cost model allowing the transfers to serve California load.
Click here to view the EIM GHG emission draft proposal for EIM regional integration.
After implementing the proposed enhancements, the ISO can then identify dispatches above the dispatch level calculated in the first run, and attribute and quantify which EIM participating resources are operating strictly to serve California load. The ISO plans to obtain additional stakeholder input. Development of an implementation timeline is in progress.
Click here to visit the ISO’s Renewables Watch webpage to view the California GHG Tracking Report, methodology paper, and an FAQ document about the report. The report will be updated monthly.