Maersk Line has signed a contract for 10 of the world’s largest, most efficient container vessels with an option to buy another 20. The vessels will have a capacity of 18,000 TEU and will be delivered from Korea’s DSME shipyard from 2013 to 2015.
The new, giant container vessels will be known as Triple-E, based on the three main purposes for their creation: Economy of scale, Energy efficiency and Environmentally improved.
At 400 metres long, 59 metres wide and 73 metres tall, the Triple-E will be the largest vessel of any type known to be in operation. Its 18,000 twenty-foot container capacity is a massive 16 % larger (2,500 TEU) than Emma Mærsk.
Key statistics on CO2 and fuel are:
* 20% less CO2 per container moved than Emma Mærsk, the most efficient container vessel in operation today.
* 50% less CO2 per container moved than the industry average on the Asia–Europe trade lane.
* 35% less fuel consumed per container than the 13,100 TEU vessels being delivered to other container shipping lines in the next few years.
The height (above baseline) of Triple-E is 73 metres which is slightly higher than Allure of the Seas (72 metres), which currently is considered the highest.
Other principal measures of the Triple-E include:
* Beam (breadth): 59 metres
* Draught: 14.5 metres
* Deadweight: 165,000 metric tonnes
* Reefer container capacity: 600
* Top speed: 23 knots
Although it is possible to operate the giant with a crew of 13, in normal operation, the vessel have a crew of 19 seafarers. If needed, it can accommodate 34 persons in total.
The top speed of the Triple-E was capped at 23 knots, two knots lower than Emma Mærsk’s top speed. This meant a power requirement of 65-70 megawatts compared to Emma’s 80 megawatts—about a 19% reduction. A slower max speed also enabled Mærsk Line to consider engines that could operate at slower revolutions—‘ultra-long stroke’— which provides the greatest fuel efficiency.
To retain the efficiency created by the slower revolutions of an ultra-long stroke engine requires a larger propeller diameter. However, the size of the propeller is limited by the dimensions of the vessel and the available space beneath the keel.
To mitigate these restrictions and achieve the desired efficiency, Mærsk Line research determined that a two engine/two propeller ‘twin skeg’ system was superior to the one engine/propeller setup. The Triple-E’s two propellers are 9.8 metres in diameter with 4 blades each, compared to Emma’s single propeller, which is 9.6 metres in diameter with 6 blades. The combined diameter of the propellers provides greater pushing power in the water and the fewer number of blades creates less resistance.
All together, the Triple-E’s twin-skeg propulsion system consumes approximately 4% less energy than Emma Mærsk’s single engine/single propeller propulsion system.
The MAN diesel engines weigh 910 metric tonnes each, and deliver output of 43,000 hp (32,065 kW). Fuel consumption is 168 grams bunker oil per kWh produced.
The Triple-E is the latest in a succession of Mærsk Line vessels (20 vessels, including the 8 Emma Mærsk class vessels) to be equipped with an energy saving advanced waste heat recovery system. For the Triple-E, the effect of the waste heat recovery system is a reduction in the engine’s fuel consumption and CO2 emissions by approximately 9%.
When exhaust gas leaves the engine, it has a very high heat potential. Utilizing this potential in an exhaust gas boiler, it is possible to generate steam. The waste heat recovery system then supplies the steam into a turbine connected to a generator which then recovers electrical energy.