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Technologies

Reducing people's exposure to diesel exhaust is a public health goal that affects engines operated at ports along with other sources of diesel emissions. Fortunately, there are many options for reducing diesel emissions from cargo handling equipment, tugboats, ferries, ships, trucks and rail yards. Below you will find information outlining technologies and strategies for reducing ports emissions, organized into six broad categories.

If you are interested in verified technologies for ports, see EPA Verified Retrofit Technologies.

Clean Fuel

Refueling refers to switching to cleaner diesel fuel through the use of advanced clean diesel fuels. EPA and the California Air Resources Board (CARB) have programs that verify the emissions performance of advanced diesel fuels, and EPA verified products have undergone rigorous testing to confirm the fuel's emissions performance. Learn more about fuel registration.

Refuel - Clean Diesel Fuels
Fuel Pertinent Information Application
(CHE = cargo handling equipment)
Diesel Fuel Pollutants Reduced: SO and ambient PM
  • Using ultra low sulfur fuels (ULSD = 15 ppm sulfur) not only reduces PM but also enables the use of retrofit technologies.
  • The easiest way to reduce pollution in all applications is to simply switch to ULSD.
  • EPA's low sulfur diesel (LSD= 500 ppm sulfur) has been in the market place for non-road, C1 and C2 marine and locomotive since June 2007.
  • ULSD is required for non-road use beginning 2010 and for locomotive and marine use beginning 2012.
 construction, CHE, marine vessels, trucks
Emulsified Diesel Pollutants Reduced: NOx (9-20%) PM (16-58%)
  • Water and additives mixed with fuel to lower combustion temperatures. Additives prevent water from contacting engine.
  • Good for centrally fueled fleets using equipment that does not sit for more than 30 days. May affect peak horsepower in some applications.
  • Costs approximately $0.01-0.20 more per gallon than standard diesel fuel.
 verified by EPA and CARB for construction, CHE, marine vessels, trucks
Biodiesel Pollutants Reduced: PM, CO, HC - Can increase NOx 2-10%
Renewable fuel (meeting ASTM spec 6751) that can be manufactured from vegetable oils or animal fats. 		verified by EPA for trucks
Natural Gas
Compressed Natural Gas (CNG)
Liquefied Natural Gas (LNG) 		Pollutants Reduced: When paired with catalysts or filters, CNG and LNG emissions are comparable to diesels outfitted with diesel particulate filters (DPFs) described below.
  • Natural gas is an inherently cleaner fuel.
  • CNG consists mainly of methane (CH4) and is drawn from gas wells or in conjunction with crude oil production.
  • LNG is compressed natural gas that is cooled to -260F degrees.
  • CNG and LNG can result in increased methane emissions.
  • Propane requires a dedicated engine.
  • Natural gas is ubiquitous in the US and can be produced domestically.
 CHE, marine vessels, rail, trucks
Liquefied Petroleum Gas (LPG or propane) Pollutants Reduced: Can reduce NOx, CO
  • Byproduct of natural gas processing and petroleum refining.
  • Requires a dedicated engine. LPG forklifts and loaders are common.
  • Primarily produced domestically.
 construction, CHE, rail, trucks

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Retrofit

Retrofit
Technology Pollutants Reduced Application
(CHE = cargo handling equipment)
Diesel Particulate Filters (DPFs) Pollutants Reduced: HC, CO, PM (85% or more reduction)
  • Honeycomb or mesh devices placed within the exhaust stream that physically trap and oxidize PM.
  • Must be paired with ultra low sulfur fuels.
  • Use either passive or active regeneration systems to oxidize the PM in the filters.
  • Passive filters require higher operating temperatures to work properly.
  • Filters require some maintenance.
  • Costs can range from $5,000-$8,000 per unit on highway equipment.
 verified by EPA and CARB for construction, CHE, trucks
Diesel Oxidation Catalysts (DOCs) Pollutants Reduced: PM (10-50%), HC (50% or more) and CO
  • Devices that oxidize pollutants in the exhaust stream and can be packaged with mufflers.
  • Established record in the highway sector and are gaining in nonroad applications.
  • Require fuels with sulfur levels of 500ppm or lower.
  • DOCs can be coupled with closed crankcase filtration technologies (see below).
  • In highway applications, DOC costs typically range from $1,000-$4,000 per vehicle and require no continual maintenance.
 verified by EPA and CARB for construction, CHE, trucks
Closed Crankcase Ventilation (CCV) Pollutants Reduced: PM reductions of about 10%, depending on a number of factors. The emissions reductions will be increased if paired with a DOC.
  • Provide a cleaner engine environment by capturing and returning oil in blow-by gasses to the crankcase.
  • Improve vehicle/equipment reliability and maintenance
  • Keep engine compartment and components clean
  • Reduce oil usage and operating costs
  • EPA's 2007 Highway Heavy Duty Diesel rule requires that engine manufacturers consider crankcase emissions as a part of overall emissions that must be reduced.
 verified by EPA and CARB for trucks with a DOC
Selective Catalytic Reduction (SCR) Pollutants Reduced: PM (about a 25% reduction) and NOx (80% reduction)
  • Inject urea (or some form of ammonia) into the exhaust stream and react over a catalyst to reduce NOx emissions.
  • Commonly used in stationary applications, such as power plants.
  • Require periodic refilling of an ammonia or urea tank.
  • Often used in conjunction with a DOC or catalyzed DPF to reduce PM emissions.
 verified by CARB for certain cargo handling and construction equipment. Used in some marine applications and locomotives.
Lean NOx Catalyst (LNC) Pollutants Reduced: NOx (5-40%) and PM
  • LNC injects diesel fuel into the exhaust stream and then catalyzes the reaction to reduce pollution.
  • Verified LNCs are paired with either a DPF which requires ultra low sulfur fuel or a DOC.
  • LNCs can increase fuel usage by 5-7%.
 verified by CARB for
trucks
Exhaust Gas Recirculation (EGR) Pollutants Reduced: NOx (40-50%), PM if paired with a DPF
  • reticulate a portion of engine exhaust back into the engine to cool peak combustion temperatures and thus reduce NOx.
  • EGR technology is being considered by some original equipment manufacturers as a way to meet upcoming engine emissions standards.
 developed for construction, CHE, trucks
Idle Reduction Pollutants Reduced: NOx, PM, CO and HC
  • Examples include shut-off devices and auxiliary power units which are portable, mounted systems that can provide climate control and power without idling.
  • Some of these technologies pay for themselves in a short time through fuel savings.
  • can save wear and tear on engines which reduces maintenance costs.
  • Can be especially effective for switcher locomotives.
 locomotives, trucks

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Repair/Rebuild

Engines that are properly maintained and tuned perform better and typically emit less particulate matter and other pollutants. Rebuilding an engine can also significantly lower emissions in some cases and can be a cost effective option for high value equipment.

Unless engines are properly maintained, other measures to reduce emissions may be futile. A poorly maintained engine can not be cleaned up by technology alone. Properly maintained or recently rebuilt engines lower emissions by burning fuel more efficiently and can reduce operation costs through improved fuel economy and extended engine life.

Common maintenance issues include:

Repower

Repowering diesel technologies refers to replacing an older engine with a newer, cleaner engine or replacing a diesel engine with one that can use alternative fuels. In some cases, a repower can include substituting a cleaner highway engine for a nonroad engine.

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Replace

Replacing an entire vehicle or machine may be the best option for equipment that is nearing the end of its useful life or was manufactured before stringent emissions standards were put in place.

Pollutants reduced are typically NOx, PM, HC, CO.

Replacing older diesel equipment with newer diesel equipment

Most cost effective when uncontrolled engines are replaced such as pre-1984 trucks or pre-1996 nonroad equipment. Typically there are benefits in fuel efficiency, reliability, warranty and maintenance costs.

Applicability: marine vessels, construction and CHE equipment, trucks and rail.

Replacing nonroad equipment with certified highway equipment built to stricter emissions standards

Highway equipment is cleaner than nonroad equipment in comparable model years. Therefore specifying highway engines in yard trucks and applicable landside equipment reduces emissions. Benefits include fuel savings and additional safety features.

Applicability: Cargo handling equipment such as yard tractors that have duty cycles similar to highway engines.

Replacing diesel equipment with electric, hybrid or alternative fuel equipment (LNG, CNG, propane).

Examples include hybrid switcher locomotives, electric cranes, LNG or LPG yard tractors, forklifts or loaders. Natural gas replacements may require fueling infrastructure.

Applicability: marine vessels, construction and CHE, trucks and rail.

Operational Strategies

Operational strategies reduce emissions by limiting the amount of time engines need to operate and creating systems to maximize efficient use of equipment. They include a variety of techniques that include improving port efficiency and reducing idling. Learn more about idle reduction technologies.

Operational Strategies
Strategy Pertinent Information Application
(CHE = cargo handling equipment)
Truck Idle Reduction Pollutants Reduced: NOx, PM, CO and HC
  • Gate efficiencies. For example, trucks park and wait for loading instead of idling in long lines.
  • Web-based appointment systems or reservation system for trucks
  • Expanded hours or incentives for off-peak operation to avoid lines
  • Reducing truck idling saves fuel and prevents unnecessary wear on truck engines.
 Highway Trucks
Shore-side Power (or cold ironing) Pollutants Reduced: NOx, PM, CO and HC
  • Uses electric shore side power at berth rather than operating auxiliary diesel engines.
  • Requires an infrastructure investment.
 marine vessels
Substituting Electric Power for Diesel Power: Electric Dredging and Electric Cranes Pollutants Reduced: Local NOx, PM, HC, CO
 Diesel dredging equipment, diesel cranes
Marine Vessel Speed Limits Pollutants Reduced: NOx, PM, CO and HC
  • Emissions typically increase with speed so enacting speed limits can reduce emissions.
  • Typically limited to a certain distance from the port. Applicability depends on port-specific configuration.
 marine vessels
Container management Pollutants Reduced: NOx, PM, CO and HC
  • Better IT management
  • Stacking practices
  • Homeland security changes
  • Direct intermodal transfers (i.e., cargo transferred directly from ship to rail)
 cargo handling equipment
More efficient freight movement Pollutants Reduced: NOx, PM, CO and HC
  • Barging or transporting by rail cargo that would normally be trucked reduces emissions and congestion.
  • Barging can also relieve traffic congestion.
 Highway trucks

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