Alternative Fuels:

Our Strategies

Western Washington Clean Cities strives to expand and strengthen our region’s alternative fuel markets. We believe a diverse mix of alternative fuels and advanced vehicle technologies will best help us achieve our petroleum displacement and air pollution reduction goals: No single alternative serves all needs or vehicle applications.



Renewable Diesel

Propane Autogas

Natural Gas

electricity biodiesel renewable diesel propane CNG


Zero tailpipe pollution.
Quiet operation. Local fuel source. Low operating cost, including reduced maintenance.

No engine conversions or extra equipment needed to use. Less tailpipe pollution, more lubricity, and higher cetane number than petroleum diesel; can be even greener when produced from waste products like used cooking oil or animal tallow.

Any diesel vehicle with no engine conversions or extra equipment needed to use.

Chemically the same as petroleum diesel

Less tailpipe pollution.

Long shelf life and excellent resistance to biological contamination.

Clean burning; made from by-product of petroleum. Quick return on investment. Costs much less per gallon than gasoline. Reduces engine noise and maintenance. Lower emissions, including almost zero particulate matter.

Clean burning, less pollution than petroleum diesel. Equivalent power to diesel engine. Generally less expensive and with greater price stability than gasoline or diesel.


Battery range (though this is expanding). Limited heavy-duty options. Higher capital costs than fossil fuel-powered vehicles. Charging infrastructure required. Sustainability depends on the source of electricity.

Not as commonly produced yet as biodiesel.  Sustainability depends on feedstock; some renewable diesel is sourced from unsustainable palm oil.

Mostly used as a blend of up to 20% with petroleum diesel. Blends above 20% may void vehicle warranties. Vehicle filters may need to be replaced when first using. Higher blends may gel at cold temperatures. Susceptible to biological contamination. Sustainability depends on feedstock.

Lower energy content than gasoline. Fuel tanks can take up a lot of space on the vehicle. Retail filling sites are limited; on-site fueling infrastructure is generally required.

Extracting natural gas can be environmentally harmful, unless it’s renewable natural gas (RNG) from sources like landfills. High infrastructure cost and low retail availability in most areas. Generally have to fill up more often due to lower energy density as compared to diesel.

Best Use/
Vehicle Type

Light-duty vehicles, fixed duty cycle.

Any diesel vehicle, used as a blend of up to 20% with either petroleum diesel or renewable diesel.

Any diesel vehicle.

Medium--duty vehicles, school buses, patrol vehicles.

High mileage and/or long distance vehicles.

Availability in Washington

Abundant, among the cheapest and cleanest in the U.S.

Available across the Pacific Northwest, including from REG and SeQuential Biofuels.

Expected to be available in WA soon, but most RD fuel now goes to LCFS states.

On-site fueling infrastructure and deliveries are provided by several companies, including Blue Star Gas and Ferrellgas.

Six retail filling stations available in the Puget Sound region.

Best Examples

Chevy Bolt, Nissan Leaf

Medium- and heavy-duty trucks; King County water taxi

Blue Bird school bus; ROUSH-equipped Ford F-250 or step van

Refuse trucks; transit buses

The role of Western Washington Clean Cities is to help develop markets for the alternative fuels that best meet the needs of our members and stakeholders. This includes assisting member fleets with identifying the most appropriate choice for each vehicle application and facilitating the development of the associated refueling infrastructure. While we focus primarily on on-road applications, Western Washington Clean Cities also supports efforts to increase the use of alternative fuels in non-road applications, such as marine, construction equipment, and generators, where appropriate. This expanded market will assist in creating greater demand and market efficiencies, as well as deliver significant air quality and health benefits.

Alternative Fuels