Cold ironing: An approach to ship’s power whose time has come

A crew prepares the cables that will supply power to the containership Xin Yang Zhou while docked in Los Angeles.

A recent study concluded that ships produce more of the sulfur oxides (SOx) that cause acid rain than all vehicles on the world’s roads, as well as nearly as much of the nitrous oxides (NOx) emissions that result in smog and particulates.

Although pollution from road vehicles has declined dramatically, emissions from large ships have changed little, while the volume of shipping has steadily increased. Without new international regulations, ship emissions of sulfur dioxide and nitrogen oxides by 2020 will surpass not only those of vehicles, but of all land sources, including power plants, factories and refineries.

Cleaning up emissions related to shipping is more of a financial challenge than a technological one. Simple measures like requiring low-sulfur diesel and speed reduction in ports can be accomplished through regulation. Clean land-based cargo-handling equipment is now maturing from the demonstration to the commercial phase.

Even alternative marine power (AMP) or “cold ironing,” which uses shore-supplied electricity to reduce diesel-engine emissions from ships while they are in port, is not a new technology. But it does require significant investments, both shipboard and onshore. For example, retrofitting container vessels for cold ironing can run from $200,000 to $500,000 per ship. Also currently, there is no universal standard for shore power systems.

The main advantage of cold ironing is that it transfers power production from dirty shipboard sources to much cleaner central power stations. (See sidebar.)

The U.S. Navy has been using shore power for decades and cold ironing is standard at its ports. The Navy originally instituted shore power not to cut pollution, but to reduce wear and tear on ship equipment. It also saves fuel. These benefits could let civilian operators amortize investment in AMP to meet emission requirements. The Navy has an advantage over commercial operations, because it could standardize connections throughout its fleet and ports.

Princess Cruises was an early civilian adopter of cold ironing, starting at Juneau in the summer of 2001. The program was expanded to Seattle in summer 2005, and shore power is now featured on 10 cruise ships. All Princess ships currently sailing from the Port of Los Angeles are fully equipped and ready to plug into shore power when it becomes available in 2008. Princess has signed an agreement committing to turning off the engines of its vessels when they dock in Los Angeles and plugging in to clean electrical power to run all on-board services during daylong calls.

Norwegian Cruise Line has signed a multiyear agreement with the Port of Los Angeles that includes the use of AMP. It will be used on its Norwegian Star, whose home port is Los Angeles.

When it comes to cold ironing, California, and specifically the ports of Long Beach and Los Angeles, are driving the technology. AMP is a key part of the San Pedro Bay Ports Clean Air Action Plan aimed at dramatically reducing port emission over the next five years. All major container, selected liquid bulk and cruise ship terminals at the Port of Los Angeles will have shoreside electricity within five years, and all container and one crude oil terminal at Long Beach will within five to 10 years. The California Air Resources Board is requiring container, passenger and refrigerated cargo ships to shut down diesel auxiliary engines while in port. The rule will apply to bulk ships, tankers and vehicle carriers next year, though the rule may be challenged in court.

Huge ship-side plugs are required for a ship whose power demand may equal that of 1,000 average-sized homes.

Containerships lend themselves to cold ironing because loading and unloading operations use shoreside cranes. Thus, diesel engines that drive the ship’s electrical generators can be shut down. Los Angeles was the first port in the world to implement shoreside power for containerships when AMP became operational at the West Basin Container Terminal at Berth 100 on June 21, 2004. On Aug. 9, 2004, NYK Atlas, the first ship built from the keel up with AMP capability, hooked up.

Electricity, supplied by the Los Angeles Department of Water and Power (LADWP), is converted to a voltage compatible to the ship through a transformer. Power at 34.5 kv is reduced to 6.6 kv and sent to the wharf outlet. A transformer barge, positioned at the rear of the ship, is plugged into the wharf outlet with a single cable. The 6.6-kv power is transformed to 440 volt by a transformer on the barge. The ship is hooked up to the barge transformer through nine separate cables and plugs, each carrying 440-volt power.

A second Los Angeles container terminal, Nippon Yusen Kabushiki Kaisha’s (NYK Line) Yusen Terminal Berths 212 to 216, became operational in 2007.

This is a next-generation AMP installation. Unlike at Berth 100, ships can plug directly into an AMP outlet contained in the wharf itself without the need for a barge conduit connecting ships to shoreside electrical power.

Long Beach has signed a lease with Matson Shipping Co. in which the company has agreed to pay the cost of outfitting five of its ships with cold-ironing equipment. Specifics of the deal were not released, but tax incentives and discounted tariffs were included as inducements for Matson.

The port will pay San Pedro-based Manson Construction Co. to build the shoreside cold-ironing infrastructure.

Thirty-eight containerships operated by NYK Line will have cold-ironing capability. Over 30 will be in service by the end of 2009. Besides 21 new ships, starting with NYK Atlas, 17 ships now in service are being retrofitted with cold-ironing technology.

In Europe, SAM Electronics has supplied an onshore power supply (OPS) facility for the Independent Maritime Terminal in Antwerp. The facility will typically enable up to three container vessels to connect to it for approximately three days within any one week. The OPS system ensures uninterrupted supply of 800-kVA (kilovolt-amps) of power to vessels. The system will be the first onshore power supply facility with automatic synchronization and 50/60 Hz conversion to be commissioned in Europe. As part of installation work, new vessels for International Container Lines will be equipped with a 60-Hz network as well as necessary OPS components such as a 6,600-volt/450-volt transformer, a 6,600-volt medium-voltage supply station and a cable drum.

In Oakland APL China tests a sytem for producing power from a shoreside generator that can burn natural gas or propane.

CleanAir Marine Power, previously Wittmar Engineering & Construction Inc., has developed an alternative system called Dual Frequency Multi Voltage Cold Ironing. DFMV could overcome the problem of many ships not being equipped for cold ironing, especially those that call infrequently at an AMP-capable port and are unlikely to have the right equipment to plug into the local electricity grid. DFMV can produce 50- or 60-Hz electricity from 380 to 480 volts so that it can supply virtually any ship calling on a port.

Rather than connecting to the electrical grid, DFMV is modular and self-contained, with electrical power produced by a turbocharged diesel-driven generator whose output can be varied in voltage and frequency. It can run on natural gas or propane for further reductions in emissions.

In a grid-based AMP system, the power is only as clean as the electric utility generating it. Often that power comes from not very clean coal-fired power plants. With financial and in-kind support from the Port of Oakland, the Bay Area Air Quality Management District, Pacific Gas & Electric and Clean Energy Fuels, full scale testing of CleanAir Marine Power’s technology was successfully completed aboard the 863-foot container vessel APL China. The diesel engine operated on liquefied natural gas.

Tankers are less amenable to cold ironing than containerships because of the pumps needed to unload cargo. Most tankers have steam turbine pumping systems. They have large diesel engines for propulsion and boilers to produce steam for the turbine-driven pumps. To retrofit tankers for AMP requires complete, and very expensive, rebuilding of the tanker’s machinery system.

However, AMP-capable tankers are appearing, primarily on dedicated routes such as the one from Alaska to Long Beach’s Berth T-121, which is being equipped with shoreside electrical power facilities. BP is retrofitting several Alaska-class oil tankers to use this first-of-its-kind oil-tanker terminal. Diesel-electric tankers, which are more suitable for cold ironing, are being constructed, but do require huge amounts of electricity delivered at a relatively constant voltage over a large operating range. These tankers are readily adaptive to AMP because they call at the same ports and at the same terminals. However, if they are going to use AMP, the port terminals will require retrofitting and some of the tankers will have to install additional equipment.

While air quality and environmental groups strongly advocate AMP, shipping companies have been less enthusiastic. For instance, they contend it costs more to have both diesel and electric capabilities for their ships. There are also safety and operational concerns about the cumbersome ship-to-shore cable connections. Terminal operators worry about the additional cost of setting up shoreside hookups. They also don’t want to foot the electricity bill, which can run thousands of dollars per ship docking. Some are skeptical about the environmental benefits of cold ironing, arguing that more energy is consumed powering a ship from the shore rather than with its own engine. Finally, there is the question of whether there is sufficient grid power available for widespread cold ironing in large ports like Los Angeles and Long Beach.

By Professional Mariner Staff