WHAT IS COLD IRONING

“Cold ironing” – providing ships with shoreside power so vessels can turn off their engines while hotelling in port – is one of the key elements of the clean air action plan (CAAP) recently adopted by the two ports. As explained in a CAAP fact sheet, the plan envisions that “all major container cargo and cruise ship terminals at the ports would be equipped with shoreside electricity within five to ten years so that vessels can shut down their diesel-powered engines while at berth.”The requirement for cold ironing is expected to spread beyond Southern California to other environmentally sensitive areas. In the past, the capital costs of cold ironing have often made it seem unattractive, but the overall life-cycle costs (compared to the cost of using shipboard fuels) have not been rigorously evaluated. The following analysis examines the financial and environmental issues surrounding cold ironing. Cold ironing infrastructure In order to allow for cold ironing, marine terminals must be equipped with extra electrical capacity, conduits, and the “plug” infrastructure that will accept power cables from a vessel. A large container ship typically requires approximately 1,600 kilowatts (kW) of power while at berth, but the power requirements can differ substantially, depending on the size of the vessel and the number of refrigerated containers on board.Although cold ironing for container ships in Los Angeles initially entailed the use of a barge to deliver the power, the future standard relies on permanent shoreside powerDesigning and constructing a terminal that is equipped for cold ironing will cost more than a conventional terminal that does not have the capability to deliver shoreside power. The cost of constructing the shoreside infrastructure, and the cost of retrofitting the vessels calling at the berth, must both be included. These extra costs will obviously differ considerably by location; this analysis uses US$1.5 million per berth for the shoreside infrastructure, based on recent documented costs for a cruise ship installation in Seattle. Assuming a 30-year design life and applying a six per cent interest rate, this translates to a shoreside construction cost equivalent to US$110,000 per year per berth. The vessels calling at the berth will also need to be equipped with the required electrical infrastructure to take advantage of shore power while hotelling. Based on recent published estimates, this analysis assumes five vessels are required to provide a weekly trans-Pacific service, at a cost of US$400,000 per vessel, or US$2 million for the fleet of five. With a 20-year vessel design life and six per cent interest, this equates to an annual cost of US$170,000 for vessel modifications to a fleet of five vessels. Adding this to the shoreside infrastructure cost yields a total annual construction cost per berth of US$280,000.

Cold ironing is a shipping industry term that first came into use when all ships had coal-fired engines. When a ship tied up at port there was no need to continue to feed the fire and the iron engines would literally cool down, eventually going completely cold, hence the term cold ironing.

Turning off the main engines whilst in port continues as a majority practice even today; yet technology applications requires that the fuel systems stay heated, the ships boilers continue to fire, and, most importantly, that the auxiliary diesel generators keep powering all activities and functions the merchant ships need to fulfill when visiting a port. These auxiliary engines are the source of electrical power on ships and are the primary source of air emissions from ships in ports today.

Recently cold ironing has been looked to as a means to mitigate air pollution by significantly reducing, and in some cases completely eliminating, harmful emissions from diesel engines. A ship can cold iron by simply connecting to another ship's power supply – a process the military navies are able to practise for many years due to adherent processes and conforming designs. This practise of connecting one ship's load to another ship's source is a tactical task and does not change the power source type and hence does not mitigate the risks of pollution involved.

Hence, cold ironing as it has evolved in communication today, signifies the process of connecting a ship's load to a more environmentally friendly, permanent, and regulated source of electrical power, under direct jurisdiction of the port nation.

Unlike the navies, whose ships can berth for very extended periods at their captive port bases, the merchant ships have shorter port stays, berthed at leased common facilities, and hence stay on power generated internally through diesel powered generators (auxiliary engines). The fuel to power these ships has always been a major cost component. Ever since the days of diesel powered ships, research was largely focused on using cheaper forms of fuel to run their engines. Ocean going ships were also traditionally not subject to emissions control which allowed for a variety of research on fuel types.

As a result merchant vessels throughout the world have been using Bunker Fuel or HFO – which is residual petroleum – as the optimal choice of fuel. This fuel, the reverse of gas oils (which are derived through distillation of crude oil), is high on particulate matter; and studies show that a single ship can produce emissions equal to the same amount as 50 million cars annually.

Further research indicates 60,000 cardio-pulmonary mortalities due to particulate matter from ship emissions. These deaths have been detected far inland, due to prevailing wind conditions. The total world trading fleet stands at 50,000+ merchant ships (Lloyds data as of January 2008). Each ship spends some 100 days in port in a year.

For every 1 kWh (3.6 MJ) of electricity, about 200 g of bunker fuel is consumed. Each 1 kg of bunker oil generates 3.1 kg of carbon dioxide. It is assessed that globally ships use 411,223,484 tonnes of fuel annually.

Keeping these reports in mind, new regulatory norms have been mandated by the International Maritime Organization (IMO). The level of sulphur is one of the benchmarks in measuring quality of fuel and Marpol Annex VI requires use of <4.5% sulphur fuel, effective 2010. The target is to reduce world maritime sulphur output to <0.5% by 2020. Some regions (e.g., California) already require ships switch to cleaner fuel when in their local waters.

Cold ironing does away with the need to burn fossil fuel onboard the ships while they are docked. Under this concept as it is promulgated, ships visiting ports are hooked on to local grid power or other power sources, which are already regulated by local pollution norms. This externally sourced power serves the ship's internal cargo handling machinery and hotelling requirements. Effectively, all the power generating sources are shut down and ship is hence cold-ironed.

This brings immediate relief from pollution by shipboard emissions and allows a more holistic maintenance schedule to be followed by ship operators, which are typically hard put to maintain planned maintenance schedules due to commercial operating pressures. The immediate result is lowered heat outputs from ships, lowered air emissions, lowered risk of accidents from fuel based machinery, lowered disturbance to the ecosystem, among various others.

Compatibility of electricity parameters: ships, having been built in diverse international yards, have no uniform voltage and frequency requirement.Some ships use 220 volts at 50 Hz, some at 60 Hz, some others use 110 volts. Primary distribution voltage can vary from 440 volts to 11 kilovolts.Load requirement varies from ship to ship and ranges from a few hundred kW in case of car carriers to a dozen or more MW in case of passenger ships or reefer ships.Connectors and cables are not internationally standardised, though work has progressed in this direction. There are other legal implications to outsourcing primary power source (see article). The legal implications stem from possible impact levels in international trade, commercial responsibilities of stakeholders and other risk as assessed.

All these problems are addressable and work has already begun in reducing ship emissions by cold ironing.Various studies are being conducted to fully implement a viable, controllable and monitored method of powering the most important arm of modern day logistics, the merchant ships. Cold Ironing is the practice of providing shore power to a ship so the ship may shut down primary and secondary combustion engines while in port. The main benefits are fuel savings and reductions in pollution and noise.

The term came into existence during the time when ships were coal fired. Once the coal fired ship was in port and attached to a shore based power source the engines no longer needed to be stoked by coal and the fires would die down until the large iron engines grew cold. Hence, cold iron became cold ironing.

Not everyone uses the same terminology. The ports in the United Kingdom use the term shore supply.Recreational vessels commonly use this practice world-wide and refer to it as shore power.

So if recreational boats use this technology and it has been around since the days of coal fired ships why isnt it used more widely?

The simple answer is cost, but there a few other issues as well.

The first is getting power to the port. This is not very difficult technology to implement but it is expensive. As an example we will use a cruise ship terminal.

The amount of amount of power necessary to meet the demands of a single ship might be fifteenmegawatts (MW). If the port can accommodate four ships the capacity needs to be at least sixty MW.

But because the port will not have four ships in port at some times only a portion of the needed capacity is used. Regardless of use the port still must incur the expense of a sixty megawatt transformer substation on site and the feeder line from the utility.

Some ports have solved this problem by growing their cold ironing capacity incrementally but this is a much more expensive solution. A single 60 MW transformer is less expensive and more efficient than four fifteen MW transformers. Utility feeds must also be upgraded as the electrical current increases.

The cable which feeds the ship is also a major expense but only a fraction of the cost of the supply and substation. These are BIG cables and need to be handled by light boom cranes, the process of connecting and disconnecting can take hours.

After expense, standardization is the next big hurdle. These heavy cables vary in size because of different voltages supplied to shore side facilities around the world. Common voltages range from 11,000 to 400 volts of alternating current (AC) with 6600 volts AC being the most common.

If you are wondering why the voltage varies so much it is because of Ohms Law. Ohms Law tells us that when voltage is increased current is reduced. To understand current think of it like water pressure in a pipe. When there is too much pressure in a water pipe the pipe will burst, in the same way too much current in a cable will destroy the cable in spectacular fashion.

When the voltage is increased from 6600 volts AC (VAC) to 11,000 VAC the size of the cable may be reduced by approximately half its thickness. Making the cable lighter saves money in materials but the value is greater in the savings of labor.

Connecting and disconnecting shore supply may take hours so even a savings of ten or twenty minutes will reduce costs significantly over the lifetime of the system. This will save ship operators some of the expense of port charges which often reach well into five figures for large vessels.

Cold ironing is expanding because of environmental regulations and public demand. Cruise ship operators are sensitive to the fact that their passengers do not want to breathe heavy fuel oil fumes if they do not want to leave a ship while in port. Some areas like the State of California require ships to burn a cleaner and more expensive fuel while in their waters.

The particulates emitted by ships are a major health concern. While at sea the crew is exposed constantly but only part of the particulate pollution makes it to populated areas on shore. In a situation where the ship is docked with engines at idle the entire exhaust plume is often directed at centers of population and commerce.

Potential future taxes on emissions and fuel cost savings are driving some projects forward, but adoption of this technology is very slow in the private sector. The early adopters of this technology are the Navies of the world.

Naval ships spend a lot of time in port. Much more than the average of one hundred days per year a merchant ship is docked. Systems like heating, cooling, refrigeration, vacuum sanitation, and data must be kept online to avoid damage to the ship and sailors while in port.

Navies have the advantage of having a bureaucracy to guide their hand. No, you didn’t misread that last sentence it did say bureaucracy is an advantage in this case. The entire fleet can use the same standard of voltage, and connection method. Ships may even power each other in some cases.

Renewable power cannot go without mention in this discussion. It is a significant possibility but much more likely to be distributed into the power grid than to exist on the grounds of a port.

Solar photovoltaic panels would take up a vast space which is generally unavailable in a crowed port area. Wind, just like solar is intermittent and would need some backup source of power like a utility feed or generator on site. If you are thinking about a battery bank it would be the size of a twenty story building.

One very specific possibility is hydroelectric power which flows constantly and has a variable capacity by controlling how much water goes into the turbine. If a port was located near an appropriate source this could be the best way to power a ship with little environmental impact. We can only dream.

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