Engine Emissions (Auxiliary Marine Engines in Port)

This section provides information about regulations requiring use of shore power by vessels docked at U.S. Ports. This practice, which is commonly known as "cold ironing", refers to shutting down auxiliary diesel engines on ships while in port and connecting to electrical power supplied at the dock, thus eliminating virtually all air pollution emissions from a ship while it is in port.

State regulations promulgated by California (California Code of Regulations Title 17, Chapter 1, Subchapter 7.5, Section 93118.3) start going into effect in 2014. Similar regulations may be developed in the future as other local and state governments tackle air emissions problems associated with their ports.

• Who is covered by the regulations?
• What is the purpose of the regulations?
• Regulations
• More Resources

Who is covered by the regulations?

California's shore power regulation applies to fleets of any U.S. Or foreign-flagged container vessel, passenger vessel, or refrigerated cargo vessel that visits a California port. In addition, the regulation also applies to owners/operators of a port or terminal where container, passenger, or refrigerated cargo vessels visit.

Fleets meeting the following criteria are not covered by the regulation: A fleet composed solely of container or refrigerated cargo vessels that visits the same California port fewer than 25 times total in a calendar year; and A fleet composed solely of passenger vessels that visits the same California port fewer than 5 times total in a calendar year.

Also exempt are auxiliary engines operating primarily on liquefied natural gas or compressed natural gas.

What is the purpose of the regulations?

The purpose of California's shore power regulation is to reduce oxides of nitrogen (Nox) and diesel particulate matter (PM) emissions from the operation of auxiliary engines on container vessels, passenger vessels, and refrigerated cargo vessels while these vessels are docked at berth at a California port. The regulation reduces emissions by limiting the time during which auxiliary diesel engines are operated on the regulated vessels while such vessels are docked at-berth in a California port, as well as by applying other requirements.

Regulations

The California shore power regulation places operational time limits on use of auxiliary diesel engines, as follows:

• Three hours total per visit to a berth, for vessels using a synchronous power transfer process to change from vessel-based power to shore-based power; or
• Five hours total per visit to a berth, for vessels not using a synchronous power transfer process to change from vessel-based power to shore-based power.

The operational time limits are being phased in, as follows:

• 2014 Requirements
  • At least 50 percent of the fleet's visits to the port must meet the onboard auxiliary diesel engine operational time limits; and
  • The fleet's onboard auxiliary-diesel-engine power generation while docked at the berth must be reduced by at least 50 percent from the fleet's baseline power generation.
• 2017 Requirements
  • At least 70 percent of the fleet's visits to the port must meet the onboard auxiliary diesel engine operational time limits; and
  • The fleet's onboard auxiliary-diesel-engine power generation while docked at the berth must be reduced by at least 70 percent from the fleet's baseline power generation.
• 2020 Requirements
  • At least 80 percent of the fleet's visits to the port must meet the onboard auxiliary diesel engine operational time limits; and
  • The fleet's onboard auxiliary-diesel-engine power generation while docked at the berth must be reduced by at least 80 percent from the fleet's baseline power generation.
    

The regulation allows for use of alternatives to shore power, such as generators, when the alternative power source meets specific standards for Nox, PM and carbon dioxide (CO2).

More Resources

Information page on shore power programs provided by the California Air Resources Board (CARB).

Cold ironing: An approach to ship's power whose time has come (Professional Mariner). Examples of shore power use and summary of alternative power systems.

California CARB. Ocean-Going Vessels at Berth Regulation.

Shore Power Technology Assessment. EPA developed this report to help port operators, state and local governments, and other stakeholders better understand and evaluate shore power as a potential emissions reduction strategy.