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Gard News 196, November 2009/January 2010


Marine diesel air emissions are being reduced by shutting off ship engines while at dock and providing less polluting shore-based power sources.

As has been read in recent media reports, in Gard News and elsewhere, the issue of marine diesel air emissions has been one that has elicited much attention of late. Actions have been taken by the IMO regarding MARPOL Annex VI, but unilateral actions have occurred in other places, prominently including the US, particularly California. These additional developments have been mainly in the regulatory, judicial, and legislative arenas.  But contemporaneously, over the past few years, more technical and practical developments have occurred in various venues, meant to address the air pollution issue head on, through reduction, prevention and control.

Alternative marine power
The most dramatic of these efforts has been in the concept of "cold ironing", more      formally known as "alternative marine power" (AMP). This concept had been employed for many years by naval vessels: while in port, the ship's engines are shut down completely and, dockside, ongoing power needs are supplied through an umbilicus of high voltage power cables, either from another ship or from shore. The reason for adopting this technology is fairly simple: by shutting off ship engines that burn more highly polluting fuels than shore-based power sources, the pollution in port areas is immediately reduced, without altering the ship's machinery or activity.



 AMP ship plugs

Photo courtesy of the Port of Los Angeles.


The system requires modifications on the ship to allow for shore power to be imported aboard, and requires installation ashore of special gantry and cables, quick disconnect connections, cable reels, and other equipment to deliver and control the power.  It is estimated that the expense to retrofit an average vessel to such power deliveries is between USD 200,000-400,000. The shore facilities can likewise be fairly expensive to establish. As an example, it was reported in 2006 that the cost to build the shore-side facility for "cold ironing" in the Port of Long Beach for Matson Line liner service ships was about USD 7 million, to be paid for by local port authorities.

One difficulty that has been encountered is that there are different voltage and frequency specifications for vessels built and operated in different parts of the world. Most ships operate on low voltage of 440V power, while large container and cruise ships operate on higher voltages of 6.6 to 11KV, and frequency requirements can vary from 50 or 60Hz.  One approach to solve this has been to use portable current convertor devices at dockside, called Dual Frequency Multi Voltage, which can overcome the compatibility problem. Perhaps, as the technology matures and becomes more prevalent, standardisation of power specifications will occur.

Efforts in the area of commercial shipping began on the US West Coast, starting with cruise ships, and quickly thereafter followed by container vessels.

Princess Cruises was an early "pioneer" in the field, instituting "cold ironing" with its DAWN PRINCESS on 24th July 2001 in the Port of Juneau.  The concept quickly spread, with expansion to Seattle, Los Angeles, Long Beach, Oakland, and other West Coast cities.  On 9th August 2004, the container vessel NYK ATLAS, the first ship purpose-built with "cold ironing" connection capabilities, hooked up at the West Basin Container Terminal in Los Angeles.

Going forward
Despite the trouble and expense, "cold ironing" as a concept is going forward at an increasing pace.  One  reason for this is that new emission regulations, and accompanying court rulings, are forcing the change, as it is one option that, while expensive, is technically feasible and yields immediate tangible results.  The Port of Long Beach, with its Green Port Initiative, has declared it will try to reduce air pollution in its jurisdiction by 90 per cent within ten years. In the Port of Los Angeles, at China Ocean Shipping's terminal, 70 per cent of the ships engage in "cold ironing" when in port.

The concept has broken out from the US West Coast, and is being established in Port Everglades, Norfolk, Houston, and other US port cities.  European ports are moving fast, not to be left behind.  In the port of Lubeck, such facilities are being used by the Finnish paper firm and charterer Stora Enso. The same parties there are discussing establishing similar facilities in Bremen, Kiel, Rostock and Hamburg, and reportedly are already using the technology in the ports of Kemi, Oulu, Zeebrugge and Gothenburg. In Asia, efforts to use this concept have also gone forward, albeit at apparently a somewhat slower pace. Some ports in Korean and China have considered installing the technology, and a facility at Hinode Pier in Tokyo is scheduled to begin operations in early 2011, but Hong  Kong and Singapore have shelved such projects, at least temporarily.

Crane with cables.
Photo courtesy of the Port of Los Angeles.

With increasing standards regarding marine air pollution, and accompanying political pressure to lower pollutants in port areas, it is fairly clear that the use of "cold ironing" is a growing trend throughout the world. The inhibiting factor at this point is the significant costs for shore-side facilities as well as vessel design modifications and equipment. This is despite the fact that some persons have questioned whether "cold ironing" really produces a net benefit for the atmosphere or not.  The criticism is that if the shore power that is being used is the product of generation by a coal-fuelled power plant, then the air pollution that was the by-product of that power that was generated was greater than that pollution that would have occurred if the ship's engines had been used to supply the equivalent power.  Some of this criticism has been addressed by responses from shore electrical power companies, that the sources of the electricity for dockside power units are indeed far cleaner than a marine diesel source equivalent.

Here to stay
It seems clear that "cold ironing" is here to stay.  How widespread it will become seems to depend on the cost of the technology, both aboard ships and ashore, and balancing that against other methods of meeting marine air emissions standards and, more importantly, ambient air pollutant levels permissible in major port areas.  Other direct remedies have been proposed to stem marine air emissions, that do not require change of fuels or procedures on ships per se.  One example is the use of an "Advanced Maritime Emissions Control System" (AMECS), which consists of a large fabric bonnet-like tube, which is fitted over the top of the ship's exhaust stack.  The bonnet collects the exhaust from the ship, and transmits it by a duct tubing to a dockside "scrubber" plant, which cleanses 99 per cent of all pollutants from the exhaust, and emits purified air.  One such device has been tested in the Port of Long Beach, but whether such "sock on a stack" technology will be used regularly remains to be seen.

Gard News 196, November 2009/January 2010

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