New incentives for clean aviation, heavy-duty trucking proposed in updates to Clean Fuel Standard

The Washington Department of Ecology is proposing updates to the state’s Clean Fuel Standard, a policy working to reduce carbon pollution from transportation fuels used in Washington. Many of the changes support greenhouse gas emissions reductions in “hard to decarbonize” sectors, such as aviation and heavy-duty trucking. 

The rulemaking proposal promotes the production and use of alternative jet fuels, also known as sustainable aviation fuels, in Washington. These non-petroleum fuels can power airplanes while producing fewer carbon emissions. Sustainable aviation fuels can also reduce air pollution. The proposal would also strengthen incentives for investing in charging equipment for zero-emission heavy-duty trucks—a key part of Washington’s climate strategy. Ecology is also considering other changes based on learnings from the program’s first two years, best practices used in other states, and input and ideas exchanged in public meetings, informal comment periods, and other external outreach efforts held during the extensive rule development period.

This rulemaking is separate from the changes to the Clean Fuel Standard set under House Bill 1409, which will strengthen the program’s carbon intensity requirements. Passed during the 2025 legislative session, the new law requires a 45% reduction in carbon intensity by 2038, up from the previous requirement of 20%. The annual reduction in carbon intensity for 2026 and 2027 is set in statute, and Ecology expects to announce a rulemaking to incorporate targets for 2028 onward into the regulations later this year.

Ecology is holding public meetings on the rule in late July and accepting public comments until 11:59 p.m. on August 1, 2025. More information about this rulemaking, including links to rulemaking documents and a full list of changes being considered, is available on our rulemaking website.