Washington Clean Fuels Standard – Carbon Intensity Model Peer Review

This peer review was conducted in support of Washington State Department of Ecology’s rulemaking for a new rule, Chapter 173-424 WAC, Clean Fuels Program Rule. As part of this peer review, the International Council on Clean Transportation (ICCT) assessed the public documents shared at the March 15, 2022 stakeholder meeting developed by Life Cycle Associates. These documents included a draft carbon intensity model to inform the development of the Clean Fuels Program (CFP) and the accompanying calculations and supporting documentation. For this peer review, ICCT assessed the methodology and results of the draft carbon intensity model, Washington Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies Model (WA-GREET), itself an update of a similar model used in California (CA-GREET). In doing so, ICCT reviewed the calculations within the model for internal consistency as well as consistency with other life-cycle models, compared the data sources & assumptions to public data and the scientific literature, as well as assessed the recommendations of the modelers for the inclusion of indirect land-use change (ILUC) emissions outside of the model.

Overall, we find that the life-cycle fuel model updates developed by Life Cycle Associates (LC Associates) largely follow the existing precedent set by the California Air Resources Board (CARB) in its comprehensive life-cycle assessment (LCA) established in the California Low-Carbon Fuel Standard (LCFS). The changes made within WA-GREET to tailor it to Washington state-specific data on fossil fuel consumption and electricity production are largely aligned with existing life-cycle assessment practices and are consistent with the intended scope of the Washington Clean Fuels Program (WA CFP). We present a high-level summary of five key fuel pathways’ emissions in Figure 1, illustrating the difference in their carbon intensity calculated for Washington in WA-GREET against values calculated for California’s LCFS using CA-GREET. The most impactful changes in the Washington analysis are the inclusion of a Washington state-average carbon intensity for electricity (resulting in a 20% decrease in electricity grid carbon intensity relative to California), and the proposed use of a different ILUC emission factor for corn ethanol (a 17.5% decline in default corn ethanol carbon intensity relative to California). Changes to the crude oil carbon intensity were much smaller, with less than 1% difference compared to California petroleum products. Throughout this peer review, we document that there are several assumptions made in the analysis or omissions based on data gaps that affect the emissions estimates for petroleum products and electricity, and offer several recommendations on addressing those data gaps and developing more accurate estimates.