Joint Study by MAN and GL on LNG as a Fuel for Container Ships

By Keith Henderson at May 31, 2012 05:50
Filed Under: Company News, General

The decision faced by owners of container ships on the best way to meet the present and future exhaust emission regulations is a complex one. MAN Diesel & Turbo together with Germanischer Lloyd have published the results of a study just completed analyzing this problem as it affects container ships.


Caption: A MAN B&W 6S70ME-GI dual fuel gas/diesel two stroke
engine rated up to 19,620 kW at 91 rpm.
Image credit: MAN Diesel & Turbo SE.

The four technologies investigated in the study are: exhaust gas cleaning by scrubber, scrubber plus Waste Heat Recovery (WHR), LNG as a fuel and LNG with WHR. For each technology, its cost in acquisition and operating, including for example revenue lost due to reduced cargo carrying capacity is included. Fuels consumption according to an assumed usage profile is also estimated.
One ship size does not fit all and in the study circumstances were considered for five sizes of container ship. The smallest is a feeder of 2,500 TEU going up to the largest of 18,000 TEU. For each ship size the speed, engine power, round trip distance and percentage of distance spent in Emission Control Areas is estimated proportionally.

The study concludes that LNG offers lower emissions and given the right circumstances, less fuel cost. LNG as a fuel compared to a scrubber system depends on investment cost of the LNG tank, the price difference between LNG and HFO and percentage of operation is an ECA. For example with 65 percent operation in an ECA, the smaller vessel sizes (2,500 TEU and 4,600 TEU) a payback time under two years is predicted. On the smallest vessel, the LNG payback time is shorter than for a scrubber system.

The largest vessel of 14,000 TEU using an LNG system, even if infrequently in an ECA, has the shortest payback time of all and is shortened further if using WHR.

The downside is however the availability of LNG and its price delivered to the ship. If the price of LNG is the same as HFO based on energy content, payback time would exceed 60 month, indicating that breakeven would only be achieved when the 2020 worldwide use of low sulfur heavy fuel oil (LSHFO) with maximum 0.5 per cent sulfur is in force.

The full report is available at: http://www.gl-group.com/en/press/news_25068.php 

 


Caption: A MAN LNG gas tank suitable for ships. MAN Diesel & Turbo has an agreement
with TGE Marine Gas Engineering, for a collaboration to offer optimum customer
solutions for gas-fuelled ships.
Image credit: MAN Diesel & Turbo SE.

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