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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 Powers America's Ports

The U.S. economy increasingly depends on international trade. In 2016, 10.6 billion tons worth of goods were sent abroad across the globe by seaborne 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 26 percent of the U.S. economy, generating $4.6 trillion in economic activity, and provide jobs for 23 million workers. Moving this 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.

Thirty-nine of the 360 commercial ports in the U.S. are located in areas of non-attainment for one or more criteria pollutant. Widely available clean diesel technologies are increasingly deployed across the large spectrum of vehicles, vessels and equipment and will play a vital role in improving air quality in regions surrounding America’s maritime gateways. 

This fact sheet will provide an overview of diesel power used in America’s ports and address several key issues relating to the use of both new and existing diesel engines and equipment including the emissions performance of new technology clean diesel engines and capabilities to modernize and upgrade existing equipment.

Click below to explore the different topics covered in this fact sheet on the use of diesel power in America's ports:

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.

Though no two ports are exactly alike, generally speaking the largest emissions contribution comes from the ocean going vessels (OGV) that include container ships, oil and gas tankers, dry bulk carriers, and “roll-on roll-off” vessels that carry automobiles and project cargoes and smaller harbor work vessels like tugs, push boats, ferries and fireboats. Other sources of emissions include truck, rail and material handling equipment.   

Port_PM_Emissions Port_Nox_Emissions





Port Activities and Air Quality

Strategies to reduce emissions from ports target three areas: reducing emissions from the trucks, trains, tugboats and cargo handling equipment servicing the port; controlling emissions from the ocean going vessels serving the ports; and improving operational efficiencies at the port.

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 starting in 2015, in the largest engines used in workboats and locomotives.

Strict emissions rules for heavy-duty trucks and vehicles established by the Environmental Protection Agency (EPA) in 2007 and further tightened in 2010 saw the adoption of clean diesel technologies in the trucking fleet. These standards result in a reduction in emissions of particulate matter (PM) and oxides of nitrogen (NOx), by 98 percent relative to a truck manufactured before 1988.  Similar emissions regulations, “Tier 4” rules were adopted for off-road equipment beginning in 2014 and apply to equipment used in port operations including harbor craft, locomotives and cargo handling equipment. The adoption of new Tier 4 diesel engines can reduce emissions by upwards of 80 percent, depending on horsepower.

Funding for Clean Diesel Vehicles and Equipment

A variety of federal and local funds are available to help owners of older vehicles and equipment purchase new or newer vehicles or engines.  These funding sources include the Diesel Emission Reduction Act (DERA), managed by U.S. EPA, and the Congestion Mitigation and Air Quality Program, managed by U.S. DOT.  In addition, many seaports operate independent programs using local funds to help incentivize equipment or engine upgrades. 

For example, funding made available through the federal DERA program between 2008 and 2015 provided roughly $158 million in matching funds for port related diesel emission reduction activities. Almost a quarter of port related funding, or $38 million was made available for the purchase of new trucks or retrofit kits to significantly reduce emissions form port trucks.  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. Many states also provide similar funding programs as well as some port authorities that provide funds, no or low-interest loans and other efforts to provide equipment owners with resources to purchase new or newer equipment.



These activities have been boosted recently through the Environmental Mitigation Trust established in the Volkswagen settlement.  Beginning in late 2018, many states will have access to $2.9 billion established in the Trust for the specific purpose of upgrade or repowering older trucks, buses and equipment.  Eligible projects include engine upgrade for switchers and marine workboats that are workhorses in many ports.

Recent research confirms that repowering older engines in these applications represent one of the most cost-effective strategies to make the most of these clean air investments to deliver needed emission reductions to near-port communities including those located in area of non-attainment.

Clean Diesel Success Story – The Ports of Long Beach and Los Angeles
Air quality in ports is rapidly improving thanks to the introduction of new clean diesel engines deployed in the many applications in ports, along with retrofit activities to install emission control technologies on older diesel engines. Nowhere is this more evident than in Southern California. The Port of Los Angeles estimates that between 2005 and 2015, fine particle emissions (PM) fell by 85 percent, or 745 tons per year, while NOx fell by 51 percent or 8,325 tons per year. Other ports have also reported similarly impressive emission reductions. The overwhelming majority of these clean air achievements are attributable to the introduction of clean diesel technology in ports.

Clean Diesel Technologies Deployed in Ports

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. Port trucks that come with the latest technology to meet near-zero emissions standards established by the EPA for trucks manufactured beginning in 2010 reduce emissions by 98 percent relative to a truck manufactured before 1988. Nationally, about one-in-three heavy-duty trucks on the road come with the latest near-zero emissions technology. 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.


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 require the use of cleaner low sulfur diesel fuel, beginning in 2012, along with a phased-in set of emissions rules for new engines. Beginning in 2015, new engines manufactured for line-haul and switch locomotives must meet the near-zero emissions “Tier 4” standards.  Clean diesel technologies developed to meet these standards will 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.



Innovative Clean Diesel Technology: Coupling Near-Zero Emissions with Fuel Savings Capabilities
Diesel engines that power large applications like locomotives and marine workboats are prided for their durability and longevity.  According to EPA, these engines have an estimated useful life of about 70 years.  While these engines are prided for their longevity, a large population of engines in operation were manufactured before emissions reduction technologies were ever required of them.  Replacing these older engines with new clean diesel technologies can yield substantial emission reductions and often with equally impressive fuel savings benefits.


One rail operator in the Port of Tacoma, WA received DERA funding to help replace older engines that power a single switch locomotives with a single clean diesel model.  In doing so, the rail operator immediately reduce 68,000 lbs. of NOx that is roughly equivalent to the emissions reduced by taking almost 22,000 cars off the road for a year.  Replacing a series of older engines with a single new clean diesel model also saved the operator 19,000 gallons of fuel each year.    


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 5 to 7 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 2010 engines. Other diesel-powered equipment, such as cranes and yard hostlers, is covered under the “Tier 4” off-road emissions rules that require 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 $158 million awarded in federal diesel emissions grant funding between 2008 and 2015 for port activities, about $25 million, or 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 by about 87 percent and emissions of NOx fell by almost 65 percent between 2005 and 2015. The Ports of Seattle, Vancouver and Tacoma estimate that emissions of NOx from cargo handling equipment fell by almost 57 percent and emissions of PM fell by 65 percent between 2005 and 2016.

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.

EPA regulations in place governing new off-road engines such as those found in cargo handling equipment and locomotives also apply to harbor craft. Those rules require that new engines manufactured beginning in 2015 that power tugboats, towboats, Great Lake freighters and stationary or auxiliary engines, just to name a few, meet “Tier 4” near zero emissions standards.  According to the EPA, these Tier 4 rules will reduce PM by 90 percent and NOx by 80 percent.

Recent research commissioned by the Diesel Technology Forum and the Environmental Defense Fund found that, on average, replacing older engines that power marine workboats with new clean diesel models can reduce NOx emissions by 30 tons per year.  This is the equivalent to taking over 26,000 cars off the road for a year. 

Replacing older marine engines is one of the most cost effective investments as clean air agencies and ports consider the use of incentive funds provided by a variety of federal programs and Environmental Mitigation Trust funds established in the recent settlement with Volkswagen.  A single workboat engine replacement project, while expensive, delivers many more emission reductions than other projects and can maximize clean air investments for near-port communities.



Case Study: Replacing Propulsion and Auxiliary Engines on the Island Eagle

In 2015, the Puget Sound Clean Air Agency using additional funds from the U.S. Maritime Administration, to replace the two propulsion engines with Tier 3 models and its auxiliary engine with a Tier 4 model on the Island Eagle, a tug boat in operation in the Port of Tacoma.  In doing so, the project delivered 3.2 tons of NOx emission reductions immediately to near-port communities while saving the operator 45,000 gallons of fuel each year resulting in over 1,000 tons of greenhouse gas emissions.

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 .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.

Other initiatives are in place to reduce OGV emissions. Many military vessels and cruise ships are deployed with the capability of cold-ironing, the ability to use shore-side electrical grid power instead of operating diesel engines while at berth. These capabilities have been deployed in the ports of Los Angeles and Long Beach for use in larger container vessels. The state of California will also require cargo and cruise vessels to shut down a proportion of auxiliary diesel engines while at berth and use cold-iron capabilities. Many ports also offer incentives to vessel operators to reduce speed when approaching marine terminals so as to reduce emissions.



America relies on its sea and river ports to deliver economic growth and provide jobs to more than 23 million workers. Clearly, America’s ports rely on diesel engines and fuel to make sure that products reach store shelves, and manufacturers receive inputs while U.S. exports reach markets overseas. While the economy is growing reliant on international trade, the equipment that moves this commerce is growing cleaner. New and newer diesel engines increasingly power the many trucks, trains, vessels and equipment that deliver commerce.


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