What is Clean Diesel?

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About Clean Diesel

Port & Marine

Moving trade through sea and river ports requires many trucks, trains, ships, cargo handling equipment, barges and marine workboats. Diesel fuel and engines are predominantly used to power these vehicles and equipment due to their fuel efficiency, power, performance and reliability.

Clean Diesel at Work in America's Ports

The U.S. economy increasingly depends on international trade. Three hundred and sixty commercial sea and river ports in the U.S. move 2 billion tons of import and export cargo each year while 16.9 million cruise passengers also move through a port facility. It should come as no surprise that ports underpin roughly 32 percent of the U.S. economy and provide jobs for 13 million workers.

Sources of Port Emissions

While every port is different in terms of the mix of cargo handled, most ports have a variety of diesel-powered equipment to move freight and provide key services to the port. These include heavy-duty trucks and other vehicles, ocean going vessels, barges, trains, tug boats and other yard equipment used to move freight. About one-in-ten of the nation's ports are located in areas classified as non-attainment for one or more pollutants including particulate matter, or soot, and oxides of nitrogen, a smog forming compound.

 Particulate Matter Emissions in the Port of Long Beach

Significant emission reduction benefits may be achieved by the adoption of clean diesel technologies that power vehicles and equipment in port operations. Clean diesel refers to the system of cleaner fuels alongside modern engine design and exhaust aftertreatment technologies to fundamentally reduce emissions from these new engines. The new generation of clean diesel technology is now available in commercial trucks, material handling equipment, and in the largest engines used in workboats and locomotives.

Clean Diesel Technology Deployed in New Engines

Port Trucks

One of the most visible applications of diesel technology at work in ports are the many trucks hauling containers and other cargo through marine terminals. The majority of these trucks are powered by diesel engines. EPA rules established in 2007 and further tightened in 2010 result in a dramatic reduction in many criteria pollutants including particulate matter and oxides of nitrogen from new diesel engines. Nationally, about 26 percent heavy-duty trucks on the road meet the latest clean truck standards established for model year 2010 and another 42 percent of heavy-duty trucks meet the first near-zero emissions standard established for model year 2007.

Many cargo ports along the East, West and Gulf Coasts recognize the need to encourage the rapid turnover of trucks used to haul cargo through ports and have adopted programs requiring or encouraging truck owners to use cleaner equipment in operation and a mix of state, federal and port authority funds are frequently available to truckers to purchase new or newer equipment.

Ocean Going Vessels

While every port is different in terms of the mix of cargo handled as well as the share of trucks, vessels, trains, tug boats and other yard equipment used to move freight, the largest emitter of emissions in ports are ocean going vessels (OGV). Given the fact that these large ships ply international waters, emissions from large ocean going vessels are regulated by a United Nation's treaty. Those rules allowed the United States to establish an emissions control area along the East, West, and Gulf Coast and in the Caribbean and require the adoption of clean diesel fuel with lower sulfur content beginning in 2010 as well as rules governing stricter emissions requirements on engines to reduce emissions of oxides of nitrogen. By January 1, 2020, the sulfur content of fuel used in ocean going vessel must not exceed 0.5 percent - a reduction from 3.5 percent allowed as of January 2, 2012. Meanwhile, new engines installed on vessels since 2011 must meet Tier 2 emissions standards and beginning in 2016 new engines must meet cleaner Tier 3 rules.

Railroads:  Line Haul and Yard Switching Locomotives

Railroads are also responsible for moving cargo through ports. The most visible types of railroad equipment in use in ports are line haul locomotives deployed with large engines typically between 3,000 and 4,000 horsepower and smaller switching engines. EPA regulations in place since 2012 require the use of cleaner low sulfur diesel fuel, along with a phased-in set of emissions rules for new engines. Those final emissions regulations were implemented in 2015 and result in near zero emissions of particulate matter and oxides of nitrogen

In addition to new engine emissions standards, many seaports adopted strategies to encourage more efficient use of railroad equipment, such as idle reduction strategies, to reduce emissions. Seaports have also encouraged the adoption of innovative switching engines that reduce emissions.

Cargo Handling Equipment

Ports use a wide variety of specialized equipment to load, unload, shuttle, stack and sort various kinds of cargo. Much of this equipment is mobile, yet some of the equipment is stationary. While every port is different, cargo handling equipment typically accounts for 3 to 20 percent of the NOx and PM emissions. 

In the Port of Los Angeles for example, about 66 percent of cargo handling equipment is powered by diesel engines. The remaining equipment is powered by natural gas, predominantly found in propane powered forklifts and yard tractors, and electricity that powers giant gantry cranes that load and unload cargo from ocean going vessels.

A variety of regulations cover the emissions from diesel engines used in this equipment. EPA rules covering on-road engines include some trucks that are found performing cargo handling functions. Those rules, mentioned earlier, significantly reduce emissions to near zero levels beginning with model year 2007 engines. Other diesel-powered equipment, such as cranes and yard hostlers, is covered under special off-road emissions rules, Tier 4 rules, that also require newer engines to achieve significant near zero emissions of PM and NOx beginning with model year 2014.

Federal, state and local port authority funds are also available to retrofit older cargo handling equipment with technologies to significantly reduce emissions. Of the roughly $160 million awarded in federal diesel emissions grant funding between 2008 and 2015 for port activities, about 16 percent helped retrofit cargo handling equipment. As an example, the Puget Sound Clean Air Agency that encompasses the ports of Tacoma and Seattle, WA, received $850,000 in DERA assistance to retrofit 74 pieces of cargo handling equipment with diesel particulate filters and closed crankcase ventilation devices.

As a result of the introduction of new clean diesel engines and equipment, retrofit activities to improve the emissions from older equipment and electrifying some stationary engines, emissions from cargo handling equipment in many ports has fallen. The Port of Los Angeles estimates that cargo handling emissions of PM have fallen over 80 percent between 2005 and 2014. The Port Authority of New York & New Jersey estimate that emissions of PM from cargo handling equipment fell by over 40 percent between 2006 and 2014.  Marine terminals in the Port Authority are committed to turnover more cargo handling equipment powered by Tier 4 engines.

Harbor Craft

Seaports and river ports are home to many marine vessels and harbor craft that help larger vessels and cruise ships navigate narrow ship channels.  Many large seaports are also home to active ferry terminals helping to transport commuters. Inland waterways and Great Lakes ports host a large population of barges and the workboats that propel these crafts. These ferries and workboats are almost exclusively powered by diesel engines. Many of these vessels will have one or more diesel engines for prime power and may also have another set of engines to provide auxiliary electrical power.

Retrofit Capabilities in Older Engines at Work in Ports

While new engines deployed in port applications - from trucks, to locomotives and harbor craft - have significantly reduced emissions, widely available clean diesel technologies are also capable of reducing emissions on older engines still in use. While retrofitting older engines is often possible, many vehicle and equipment owners find it advantageous to repower older equipment with a new engine or even scrap older equipment and purchase new. A variety of funds provided by the federal government as well as states, localities and port authorities helps incentivize owners of older vehicles and equipment to retrofit, repower or replace older engines.

Nationally, the Diesel Emission Reduction Act (DERA) funding assistance has provided roughly $158.6 million between 2008 and 2015 to incentivize the adoption of new or newer diesel technologies in older vehicles and equipment found in ports. In order to receive funding assistance, a project applicant must demonstrate the availability of non-federal matching funds. Nationally, every $1 in DERA assistance is met with another $3 in non-federal matching funds to provide, on average, $13 in environmental benefits. As an example, the Port Authority of New York and New Jersey, used DERA assistance to help retrofit two switcher locomotives that are estimated to reduce NOx by185 tons and 4.5 tons of PM.

Marine Engines

Upgrading or replacing older marine engines is the largest category of engines receiving federal incentive funding. Of the roughly $160 million made available to upgrade or replace older engines in port service through the Diesel Emission Reduction Act program, almost half of funding, or $97 million, was awarded to projects that included engines on harbor craft and other vessels. As an example, the New York City Department of Transportation was awarded $2 million to help upgrade four older engines on a Staten Island Ferry while the Port of Houston was awarded $2.86 million to upgrade or replace 96 older marine engines.

Port Trucks

Roughly 15 percent of port related funding, or about $25 million was made available for projects that included the purchase of new trucks or retrofit kits to significantly reduce emissions form port trucks.vii As an example, the Port Authority of New York-New Jersey received $7 million in DERA assistance coupled with an additional $21 million in non-federal matching funds to help replace 636 older dray trucks with new equipment.

Cargo Handling Equipment

Of the roughly $160 million awarded in federal diesel emissions grant funding between 2008 and 2010 for port activities, more that $26 million, or 16 percent, was awarded to projects that included the retrofit cargo handling equipment. As an example, the Puget Sound Clean Air Agency that encompasses the ports of Tacoma and Seattle, WA, received $850,000 in DERA assistance to retrofit 74 pieces of cargo handling equipment with diesel particulate filters and closed crankcase ventilation devices.


The adoption of clean diesel technologies in new engine found at work in ports and the retrofit or repowering of older equipment and vehicles is improving air quality in many ports. For example, the Port of Los Angeles estimates that between 2005 and 2014, PM fell by almost 85 percent. Nowhere is the clean diesel success story more prevalent than the adoption of clean diesel trucks.  The Port of Los Angeles and Long Beach both report that particulate matter emissions attributable to harbor trucks have fallen by more than 97% between 2005 and 2014.  Other ports have also reported similarly impressive emission reductions. The Port Authority of New York & New Jersey reports than PM emissions have fallen by more than 50 percent between 2006 and 2014.  The overwhelming majority of these clean air achievements are attributable to the introduction of clean diesel technology in ports.

Additional Resources

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What is Clean Diesel?

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