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Power and automation technology group, ABB, is launching a new Dynamic AC (DAC) concept that is said to optimize engine speed, leading to significant fuel savings. It is the latest addition to a line of ABB products that includes Azipod propulsion and the Onboard DC Grid, which maximize energy efficiency for vessel owners.

According to ABB, a large cruise ship can achieve up to 6 percent (or up to 2,000 tonnes of fuel) of annual savings by engine speed optimization. The concept has been created with a simple configuration of electrical system using existing and proven ABB components, which is said to ensure quality and reliability.

"The concept is new to the commercial maritime industry," ABB explained in a statement.

"No matter what bunker costs are now, ship owners look to the long term and always want ways to maximize fuel efficiency," commented Juha Koskela, Managing Director of ABB's Marine and Ports business. "Once again, our strong emphasis on research and development has produced a solution of great business value to our customers."

Dynamic AC is said to adjust the rotational speed of the diesel generating sets, allowing the system frequency to vary within the specified range. Currently, many ships still run with their generators at a set speed, regardless of the power requirement, creating a surplus of wasted energy. The medium voltage power system in the ship is specially engineered for variable frequency, including component design and system integration. Distribution for the auxiliary and hotel loads is provided by frequency converters or directly from the variable frequency system.

"ABB has had great success providing power and propulsion solutions to the cruise industry. Dynamic AC is another tool for cruise companies to build fleets which are more efficient and more environmentally friendly," added Koskela.

Dynamic AC will sit alongside the Onboard DC Grid in ABB's portfolio of power distribution products designed to increase ship fuel efficiency. Whereas the Onboard DC Grid is targeted towards improving the performance of vessels with a lower power requirement, Dynamic AC is aimed at larger ships with power of 20 megawatts (MW) or more.