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Shore-Based Power: Reducing Idle Ships' Emissions

John-Michael Cross

In two minutes, an average idling car engine consumes an amount of fuel equivalent to the amount required to propel the same car for one mile (i). Ten seconds of idling uses the same amount of fuel as shutting off and restarting the engine (ii). Millions of tons of greenhouse gases would be saved every year by shutting off vehicles on jammed freeways, loading docks and other altars of idle-worship.

Emissions from idling engines are not limited to cars and trucks. Standard operating procedure for almost every large ship is to keep its diesel engine running the entire time the ship is docked at port. This allows ships to run their auxiliary electrical systems. Ships burn bunker fuel, often without many emissions controls, which releases large amounts of carbon dioxide, black carbon, and other air pollutants. In-port idling to generate electricity is a particularly inefficient use of bunker fuel. In an eight-hour stay in port, a ship can easily emit over 2.5 tons of pollutants (iii). In the United States alone, over 100 ports combine to handle 57,000 dockings each year (iv).

Ports are often hubs of economic activity with large population centers. Idling ships spew diesel fumes into these port areas, resulting in high pollution concentrations that have direct effects on public health. Particulate matter (PM), including black carbon, causes a wide range of cardiopulmonary diseases. One study attributes marine shipping-related PM emissions to cause 60,000 deaths annually, with the majority of deaths concentrated in coastal areas on major trade routes (v). Non-particulate emissions, such as SO2, NOX, carbon monoxide and other toxic chemicals highly concentrated in non-filtered diesel exhaust add to the public health burden in coastal communities.

This problem can largely be alleviated simply by plugging docked ships into the local electrical grid. Known as ‘alternative marine power’ or ‘cold ironing,’ this practice allows ships to completely shut down their diesel engines for the entirety of their stay in port (vi). The term ‘cold ironing’ dates back to when ships were fueled by coal-fired iron-clad engines; these engines would be deprived of coal at port and slowly go cold (vii). In addition to emissions and fuel savings, ships benefit by reducing wear on their engines that would come from constant operation.

Cruise ships, container ships and other large vessels can take advantage of shore-based power provided they have been outfitted to do so. Most existing ships are not built with such capability, but retrofit programs are becoming increasingly popular (viii). Oil tankers can also utilize shore-based power, but require specialized on-shore infrastructure that is both more powerful and expensive to provide the energy necessary to pump its cargo in and out of the ship (ix).

Cold ironing requires capital investments from operators of both ships and ports. Retrofitting a container ship with the proper technology will cost between $200,000 and $500,000 (x). The corresponding dockside equipment costs $1.8 million to $2.5 million per unit (xi). Neither side's investment can pay off without the effort of the other, which has slowed adoption of cold iron technology. Early adopters have disproportionately been those that own both the ships and the dock, such as the United States Navy and cruise lines. The U.S. Navy has widely utilized cold ironing for decades after recognizing the benefits in fuel saving and reducing wear on ship engines. Princess Cruise Line has installed shore power capacity in much of its fleet and made its ports compatible in Juneau, Seattle and Los Angeles over the past decade (xii).

Operating costs for shore-based power are competitive with idling on bunker fuel, though fluctuations in oil prices and between ports' electricity rates complicates the comparison. One study found that a typical cruise ship would spend $450-$550 per hour for shore-based power, compared with $425-$450 per hour by burning bunker fuel. However, if the same ship is required to use higher quality fuel to limit its emissions, the idling cost jumps to nearly $800 an hour (xiii). Wide adoption of such fuel standards would transform operating costs of cold ironing from a near-push to a clear economic advantage over diesel fuel use.

Until recently, the shipping industry was subject to very little environmental regulation. Limited development and adoption of clean technologies reflected that reality. In March, the International Maritime Organization finalized a plan to establish emission control areas off the coasts of the United States in Canada beginning in 2012. The plan will require ships traveling within 200 miles of shore to drastically reduce their emissions of particulate matter, SO2 and NOX, achievable partly through consumption of higher quality fuel (xiv). The U.S. Environmental Protection Agency announced plans last year for similar emission standards for all U.S.-flagged ships (xv). Higher fuel costs will make cold ironing a more attractive investment, which in turn will facilitate ships' compliance with the new emissions standards.

Benefits of shore-based power are partially curbed by present circumstances. Many ports are supplied with coal-fired electricity, diminishing savings in greenhouse gas emissions from switching off diesel fuel, though particulate matter reductions are maintained. Additionally, there is no current international standard for cold ironing technology (xvi). Creating such a standard will allow ships to tap into shore-based power at any port.

By cold ironing, large ships are able to reduce engine wear and avoid higher operating costs that will soon result from new regulations. Greenhouse gas and black carbon emissions are reduced, benefitting the global climate. Local air pollution in port cities is drastically cut, saving thousands of lives. Such benefits strongly suggest that implementation of this strategy should rapidly move forward.

References

i. California Energy Commission Consumer Energy Center. “Idling Your Car.” 2006.

ii. American Society of Mechanical Engineers – Florida Section. “Idle Versus Restart.” Mechanical Engineering. June 2007.

iii. Cornwall, Warren. “Cruise ships plugging into Port; Power from city's electrical grid; Effort to cut pollution.” Seattle Times. 3 May 2010.

iv. “Dirty Bunker Fuel Banned for Large Ships in U.S., Canadian Waters.” Environment News Service. 26 March 2010.

v. Corbett, James J., James J. Winebrake, Erin H. Green, Prasad Kasibhatla, Veronika Eyring, and Axel Lauer. “Mortality from Ship Emissions: A Global Assessment.” Environmental Science and Technology. 15 December 2007. 41(24):8512-8. PDF.

vi. Siuru, Bill. “Cold ironing: An approach to ship’s power whose time has come.” Professional Mariner. Issue #113, May 2008.

vii. Hare, B. and G. Atkinson-Hope. “Harmonic Measurements on Ships and Cold-Ironing.” Cape Peninsula University of Technology Industrial and Commercial Use of Energy Conference 2009. PDF.

viii. Kanter, James. “Italians to Electrify Cruise Ships in Port.” New York Times Green Blog. 2 February 2010.

ix. Hanson, Kristopher. “Oil tanker at Port of Long Beach is a green first.” Long Beach Press-Telegram. 3 June 2009.

x. Siuru, Bill. “Cold ironing: An approach to ship’s power whose time has come.” Professional Mariner. Issue #113, May 2008.

xi. Shore, Teri, Tom Plenys, and Diane Bailey. “Feasibility of Providing Shore-Based Electrical Power to Ships while Docked: Environmental Perspective.” Position Paper for California Air Resources Board Public Consultation Meeting. 9 November 2004. PDF.

xii. Siuru, Bill. “Cold ironing: An approach to ship’s power whose time has come.” Professional Mariner. Issue #113, May 2008.

xiii. Shore, Teri, Tom Plenys, and Diane Bailey. “Feasibility of Providing Shore-Based Electrical Power to Ships while Docked: Environmental Perspective.” Position Paper for California Air Resources Board Public Consultation Meeting. 9 November 2004. PDF.

xiv. Bravender, Robin. “Emission-Cutting Plans Approved for U.S., Canadian Coasts.” New York Times Greenwire. 26 March 2010.

xv. Pentland, William. “EPA Cracks Down on Ship Emissions: Enter Cold Ironing.” Clean Tech Law & Business. 2 July 2009.

xvi. Paul, D. and V. Haddadian. “Cold ironing - power system grounding and safety analysis.” Industry Applications Conference, 2005. Fourtieth IAS Annual Meeting. Conference Record of the 2005. 2-6 October 2005. 2: 1503-11.

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