Wärtsilä Corporation

Optimum speed of LNG carriers with Dual Fuel Engines

Wärtsilä’s recent successful application of dual-fuel internal combustion engines to LNG carriers promises significant benefits for these vessels including higher operating speeds and lower transportation costs. Wärtsilä has now completed a study to determine the optimum size and speed of these vessels, to maximize the benefits of DF technology.

DF engines in LNG Carriers

During the past three to four years, Wärtsilä has carefully compared various machinery alternatives for LNG carriers based on diesel, high-pressure gas-diesel and low-pressure dual-fuel engine technology, with or without onboard boil-off gas reliquefaction, as well as installations based on gas turbine technology, and found that dual-fuel-electric LNG carriers are the most attractive alternative to traditional steam turbine installations.

The dual-fuel-electric machinery concept combines multiple dual-fuel engines with an electric propulsion system and offers a very significant improvement compared to steam in terms of operating economy, exhaust gas emissions and redundancy. At the same time, issues like safety, reliability and maintainability are kept at appropriate levels.

Dual-fuel engines can run on gas, but can alternatively operate on marine diesel oil or heavy fuel oil. This fuel flexibility is an important asset for LNG carrier operators in a world in which nothing seems harder to predict than the development of oil and gas prices.

Thirteen dual-fuel-electric LNG carriers have been ordered so far by five different ship owners at three different shipyards, and options are held on seven more ships. The first dual-fuel-electric LNG carrier to be ordered was the 75’000 m 3Gaz de France Energy. This ship, at the point of being delivered to Gaz de France by Alstom Chantiers de l’Atlantique of France, is equipped with four six-cylinder Wärtsilä 50DF dual-fuel engines. Two further dual-fuel-electric LNG carriers ordered from Alstom Chantiers de l’Atlantique by Gaz de France and a consortium of Nippon Yusen Kaisha (NYK) of Japan and Gaz de France respectively are the 154’000 m 3Provalys and Gaselys. These ships will be delivered this and next year and will each be equipped with three twelve-cylinder and one six-cylinder Wärtsilä 50DF dual-fuel engines. In autumn last year, BP Shipping ordered four 155’000 m 3 dual-fuel-electric LNG carriers at Hyundai Heavy Industries and Hyundai Samho Heavy Industries in Korea. These ships will be delivered in 2007 and 2008 and will each be equipped with two twelve-cylinder and two nine-cylinder Wärtsilä 50DF dual-fuel engines. Early this year, AP Møller of Denmark and Kawasaki Kisen Kaisha (K-Line) of Japan ordered respectively four and two 153’000 m 3 dual-fuel-electric LNG carriers at Samsung Heavy Industries in Korea. These ships are scheduled for delivery in 2008 and 2009 and will be powered by three twelve-cylinder and one six-cylinder Wärtsilä 50DF dual-fuel engines. More orders are expected anytime soon.

Wärtsilä is the leading supplier of ship machinery, propulsion and manoeuvring solutions for all types of marine vessels and offshore applications. Wärtsilä’s own global service network takes complete care of customers’ ship machinery at every lifecycle stage.

Wärtsilä’s ship power solutions are based on technological expertise, close customer co-operation and industry-leading innovations spanning the complete range of marine power and propulsion needs. These solutions are customized to the specific ship design and operational requirements, ensuring maximum efficiency, reliability and environmental performance over the entire lifecycle of the installation.

www.wartsila.com

customerservice.marine@wartsila.com