Dual-Fuel Propulsion System for LNG Carrier

Source: Marinelink

Hyundai Heavy Industries Co., Ltd. (HHI) has developed the first Korean Dual-Fuel Diesel-Electric (DFDE) propulsion system for LNG carriers. The DFDE propulsion system uses either oil or gas, depending on the situation. It uses an electric motor like large cruise ships and submarines, not a steam turbine, which is the traditional propulsion system for LNG carriers. The DFDE propulsion system improves fuel efficiency, reacts quickly, and provides a smooth voyage.

HHI was guided by both environmental and economic requirements while developing the Integrated Automation System, which includes the main engine, the electric propulsion system, other control systems, and the Ecobot. The Ecobot is the heart of the DFDE system, using any LNG gas that evaporates during transit to fuel the main engine. The DFDE propulsion system is expensive, costing roughly two to four percent more than traditional steam-turbine propulsion systems; within 5 years, however, the savings in fuel costs will more than make up for the initial extra cost.

HHI has delivered a 155,000 cu. m. LNG carrier with a DFDE propulsion system. The ship, ordered by BP of the United Kingdom, was named British Emerald. British Emerald runs faster than traditional LNG carriers when using the same amount of fuel, and when running at a speed of 20 knots, the DFDE system reduces fuel consumption by 40 tons per day compared to a steam-turbine propulsion ship, which uses 180 tons of fuel per day at that speed.

“The biggest reason we chose the DFDE propulsion system was for the environment. But it was a big adventure when we ordered it,” said Mr. Adrian Howard, vice-chairman of technical management at BP.

“All LNG carriers had steam-turbine propulsion systems when we received the order in 2004. It was exciting to get a chance to develop the first alternative system with this order,” said an HHI representative.

HHI received an order for six LNG carriers with DFDE propulsion systems (including two ships for Hyundai Samho Heavy Industries) in September 2004. The first of the six ships completed, British Emerald, is 288m in length, 44.2m in width, 26m in depth, and has a service speed of 20 knots.

The development of the DFDE propulsion system is the result of 30 years of LNG carrier R&D experience. HHI began its research and development on LNG carriers at the end of the 1970s, building the world’s sixth, and Korea’s first, LNG carrier in 1990.

HHI plans to produce the duel-fuel engine and most of the core equipment, including the electric motor, switchboard, and generator, in Korea by 2008.