The Washington Clean Fuel Standard (WA CFS) market aims to lower the carbon intensity of transportation fuels by incentivizing low-carbon alternatives through a credit and deficit system. It plays a key role in decarbonizing the fuel supply, advancing renewable diesel (RD), biodiesel (BD), and other clean fuels to meet state emissions targets. To assist stakeholders in navigating this landscape, cCarbon has developed the WA CFS Scenario Simulator. This tool offers insights into credit generation, deficits, and blending trends across fuel pools. By enabling users to adjust key parameters and assess market dynamics, the simulator facilitates informed decision-making in the WA CFS market.

Model Change Log

On May 17, 2025, Washington State strengthened its clean fuels program through the passage of Second Substitute House Bill 1409, increasing carbon intensity reduction stringency and introducing a refined framework for compliance, enforcement, and transparency. The Scenario Simulator has been updated to reflect these amendments and is now calibrated with the Q3 2025 credit report. A custom ZEV scenario has also been added, enabling users to model ZEV sales as a percentage of total LDV sales. Click here for the Explainer!

The Washington Clean Fuel Standard (WA CFS) is a rapidly evolving clean fuel program aimed at reducing the carbon intensity (CI) of transportation fuels in Washington. Launched in 2023, the program follows a credit-based system similar to other West Coast markets, requiring fuel suppliers to progressively lower emissions while promoting the adoption of low-carbon alternatives.

Under the program, fuels with lower CI—such as renewable diesel, electricity, and renewable natural gas (RNG)—generate credits, while conventional fuels like gasoline and diesel generate deficits. This creates a compliance market where obligated parties must balance deficits with credits, driving investment toward cleaner fuel pathways.

A major development in the program is the passage of House Bill 1409, which significantly strengthens the policy framework. The bill increases the CI reduction target from 20% to 45% by 2038, with a potential extension to 55% depending on climate benchmarks. It also introduces stricter compliance penalties and mandates annual CI reductions of 3–4% for transportation fuels starting in 2028, making Washington one of the most ambitious clean fuel markets in the United States.

Despite these ambitious targets, current market dynamics present challenges. Washington’s fuel mix remains heavily dependent on gasoline and diesel, while renewable fuel adoption—particularly renewable diesel—has shown volatility in blending rates. This has contributed to fluctuations in credit generation, with a notable decline in biofuel credits in recent periods.

Electric vehicles (EVs) are expected to play a critical role in future compliance, with electricity credits becoming increasingly important. However, variability in EV adoption trends adds uncertainty to long-term credit supply. Additionally, the availability of low-CI fuels and the pace of infrastructure development will be crucial in meeting tightening targets.

Looking ahead, the WA CFS is likely to transition into a credit-tight market as targets become more stringent. Rising compliance pressure is expected to push credit prices upward, making early investment in clean fuel supply chains and EV infrastructure essential for managing future costs and ensuring market stability.