Electrification at Ports: Plug-Ins Enabled

Electrified RTGs at Georgia Ports Authority's Garden City Terminal near Savannah.  (GPA Photo/Stephen Morton)

Electrified RTGs at Georgia Ports Authority’s Garden City Terminal near Savannah. (GPA Photo/Stephen Morton)

More ports are powering their operations from the grid, creating a new set of assumptions about cost and reliability.

By Meredith Martino

Operating costs and efficiency are important considerations for all ports, but for the Georgia Ports Authority (GPA), the issues are especially front and center. With no private marine terminal operator responsible for terminal infrastructure or cargo handling, GPA has a direct and immediate stake in the way its cargo handling equipment performs and the costs associated with running it.

Two decades ago, the port didn’t like what it saw.

“All of our cranes were diesel, and they were having 3.8 percent downtime,” explained Rich Cox, who worked as GPA’s general manager of equipment and facilities maintenance for more than 18 years before retiring last fall. “We wanted to get that downtime to less than 1 percent.”

When GPA began investigating electric-powered cranes, they ran into constraints, as cranes that utilized 480V power could only travel approximately 900 feet from the power source. When another power option became viable – in the form of a 13,800V feed to cranes – the math started to change, as the cables for the higher voltage could allow travel of up to 2,300 feet from the power source.

“We purchased two electric cranes, and the reliability got better and the maintenance costs went down,” said Cox.

GPA made plans to convert seven more cranes from diesel to electric and implemented the change in 2000. All ship-to-shore cranes at GPA facilities are now electrified, and the port is now turning to electrifying rubber-tired gantry cranes. In 2011, the port did a demonstration project using a Conductix system, and the port now has an additional 11 electrified RTGs. Though they can still run on diesel, they use electric power approximately 95 percent of the time.

“The payback period is about 5.2 years, considering capital and diesel savings,” Cox explained. “By not running diesel all the time, we have significantly extended our maintenance costs.”

However, while the change has yielded many benefits for GPA, it has created some new challenges as well.

About six years ago, there was a wind storm that wiped out the transmission lines of Georgia Power, the local utility that supplies power to the GPA facilities. The port lost power for about 12 hours.

“The likelihood of all the diesels failing at once was very unlikely,” said Cox, who continues to consult part-time for GPA. “Now, if you lose power, you lose all of them.”

GPA and Georgia Power learned a lesson from the wind storm and have constructed parallel pathways from the local substation to ensure redundancy in the supply. However, GPA has investigated the use of microturbines as a temporary power source to address the supply concerns.

Utilizing microturbines, fuel cells, solar, natural gas and other alternative sources are a key component of microgrids, a way to achieve local power goals.

“The ultimate goal is resiliency,” said Clay Sandidge, president of Muni-Fed Energy. “It’s ensuring reliability and resiliency for total overall demand.”

Sandidge explained that municipalities, ports, universities and others are turning to microgrids as part of their energy strategies, which also include efforts to reduce consumption where possible. It often makes good sense to power sources of consistent energy consumption, such as high-mass lighting, cranes/yard equipment and buildings, with a microgrid. A port might set a goal of providing 20, 50 or 70 percent of its power from a microgrid.

“In a disaster or catastrophe, things are still running because a portion of the power supply is ‘islanded,’” Sandidge said. “And if the grid is not down, a microgrid can redeploy power into the system.”

While reliability is one of the most appealing aspects of utilizing a microgrid, it can also help address power costs. Utilizing alternative energy, such as natural gas, in a long-term contract can be very attractive for operations managers, as the strategy enables them to lock in costs and have a better knowledge of what their energy costs will be in the long run.

Sandidge said many ports are looking at using microgrids to baseline a portion of the power needed for a marine terminal. For example, a port might seek to provide 4 megawatts of power from a microgrid for a terminal that runs on 10 megawatts of power.

“A microgrid can be as small as 100 kilowatts or as large as 100 megawatts,” said Sandidge. They are attractive because they offer “better management of energy usage, high quality power and reliability and resiliency of power.”

A supply of reasonably priced, reliable power is the No. 1 priority for large-scale electrification efforts at ports, including shore power for vessels. A number of ports have built infrastructure to electrify cruise ships while at berth.

The Halifax Port Authority announced last year that it will be the first port in Atlantic Canada to provide shore power for the 2014 season. Part of a $10-million cooperative initiative between the Government of Canada, the Province of Nova Scotia and the Halifax Port Authority, the project gained traction because of the air quality benefits associated with allowing ships to plug in and turn off their auxiliary engines. Typically, vessels are in port for approximately nine hours, and during that time if connected to shore power, there would be no carbon dioxide (CO2), mono nitrogen oxides (NOx), sulfur oxides (SOx) or particulate matter (PM) emissions from the vessel auxiliary generators.

At Carnival Corporation, cruise ships have been utilizing shore power for about 10 years. The first installation was in Juneau, Alaska, and others have followed in Vancouver, Seattle, San Francisco, Los Angeles, Long Beach and San Diego. Shore power is being installed in New York at Brooklyn’s Red Hook Terminal, and in addition to the work being done in Halifax, shore power is under consideration at other Canadian ports.

Because cruise ships already have auxiliary engines that can be utilized, the reliability of the power supply itself is of less concern. The primary issue for powering cruise ships is the large load requirement. It can be 12 megawatts, compared to a cargo ship that might only be 1-1.5 megawatts.

“Most homeports are in or near large communities,” said Tom Dow, vice president of public affairs, at Carnival Corporation. “All utilities are looking at shedding or constraining loads.”

There is a high cost of putting in place distribution infrastructure for the large, irregular loads associated with cruise ships. It can be $1.5-$2 million per vessel to retrofit the vessel to be able to connect to a power supply, plus the cost of landside infrastructure to provide the power. “The shipboard economics are difficult,” said Dow.

Because of the costs associated, cruise ships are looking to exhaust scrubbers to address air quality concerns as an alternative to shore power. Scrubber technology has advanced in the past several years to where emissions can be reliably calculated as the equivalent of .05 percent sulfur fuel, well below the .10 percent sulfur fuel requirement for the North American Emissions Control Area that will go into effect in 2015. However, Dow thinks that installations that already utilize shore power for cruise vessels will continue to do so, despite the progress on scrubbers.

It’s likely that ports will continue to find new and innovative ways to utilize grid power for their operations, solving some problems such as air emissions or maintenance costs of diesel equipment but encountering new challenges such as reliability and resiliency. New solutions, such as microgrids and better cooperation with utilities, will be necessary, but ports are forging ahead to make these solutions realities.