A Glance at Clean Freight Strategies: 

Cleaner Fuels for Drayage 

Alternative fuel use can reduce the consumption of diesel fuel and lower emissions of 

greenhouse gases and various air pollutants. One fuel alternative, B20 biodiesel could save 

more than 1,100 gallons of fuel, eliminating 12 tons of carbon dioxide per truck each year and 

reducing sulphur dioxide emissions by 3-11%. 

What is the challenge?

Emissions generated through the daily 

convergence of diesel trucks on port 

facilities can undermine local air quality. 

These trucks emit substantially more 

particulate matter (PM), volatile organic 

compounds (VOCs), nitrogen oxide 

(NOx), carbon monoxide (CO) and 

carbon dioxide (CO2) per mile than lightduty vehicles. While trucks are critical to 

local and national economies, they can 

have costly health impacts in the 

communities they travel through. 

Emissions from diesel trucks have 

improved with cleaner engine and after 

treatment technologies, but the 

challenge to minimize pollution per trip 

remains for drayage trucks that typically 

predate newer control technologies. 

What is the solution? 

Alternatives to conventional diesel fuel 

can reduce the air quality impacts of 

freight. Drayage fleets can be suited to 

alternative fuel use due to frequent 

travel to port and warehouse facilities 

where refueling stations could be 

located. The higher cost of these fuels 

can sometimes be offset by government 

grants. Options for heavy-duty on-road 

applications include: 

Biodiesel 

Biodiesel is a renewable alternative to 

petroleum diesel that can be refined 

from a variety of animal fats and 

vegetable oils. It is an attractive option 

because at lower percentage blends 

biodiesel can run in unmodified diesel 

engines, and is compatible with many 

emission control devices. Potential 

sulfur dioxide (SO2) and CO2 reductions 

can be significant depending on the 

percentage of biodiesel used. B20, a 

common biodiesel blend, contains a 

mixture of 20% biodiesel and 80% 

petroleum diesel. Most major engine 

companies recognize the use of blends 

up to B20 as compatible with engine 

warranties. 

Diesel Emulsion 

Diesel/water emulsions combine 80% 

diesel fuel with water and additives. 

This can reduce nitrogen oxide and 

particulate matter emissions by altering 

combustion temperatures and patterns 

to more completely burn the fuel. 

Emulsions do not require vehicle 

modifications and can be used in with 

many after-treatment technologies. 

Emulsions can be easily applied to 

centrally fueled fleets. 

Ultra-low Sulfur Diesel (ULSD) 

ULSD has been refined to have a lower 

sulfur content then conventional diesel 

and can be used in any on-road diesel 

engine applications. Today, diesel fuel 

has a maximum sulfur content of 500 

parts per million (ppm) while USLD 

ranges from 15 to 30 ppm of sulfur. 

EPA has mandated the use of USLD in 

all on-road diesel engines by 2006. 

The results are in . . . 

Each alternative fuel option has different 

U.S. EPA Office of Transportation & Air Quality ! EPA420-F-06-007 ! (734) 214-4767 phone ! smartway_transport@epa.gov ! 

www.epa.gov/smartway 
advantages for use in drayage 

applications. 

 Biodiesel can reduce lifecycle 

greenhouse gas emissions over 

conventional diesel 10-20% for B20 

and 40-90% for B100. carbon 

monoxide, particulate matter, volitale 

organic compounds and sulphur 

dioxide reductions can range from 3-

11% for B20, with a potential 

increase in NOx emissions. 

 Purinox diesel/water emulsion 

produced by Lubrizol Corp. has been 

verified by the California Air 

Resources Board (CARB) to reduce 

NOx and PM emissions. Estimates 

include a PM reduction of 50% and 

15% for NOx. However, such 

emulsions can result in fuel economy 

losses of 15% and up to a 20% 

reduction in engine power. 

 In addition to reducing the maximum 

sulfur content of diesel by 97%, 

ULSD provides the greatest 

emissions benefits when used with 

emission control devices. ULSD 

enables the effective use of 

particulate traps and catalytic 

converters resulting in reductions of 

PM, VOC and CO by as much as 

90%. 

Next steps

Ports and nearby communities can act 

as a central point for the refueling of 

alternative fueled trucks, and support 

the development of refueling stations. 

Information on heavy-duty applications 

for alternative fuels and diesel fuel 

regulatory programs can be found 

through the EPA’s National Clean Diesel 

Campaign (www.epa.gov/cleandiesel) 

and the Alternative Fuel Data Center 

(www.eere.energy.gov/afdc/). 

U.S. EPA Office of Transportation & Air Quality ! EPA420-F-06-007 ! (734) 214-4767 phone ! smartway_transport@epa.gov ! 

www.epa.gov/smartway