- LNG demand has spurred operators to battery-hybrid propulsion as a means of reducing operational costs and emissions.
- Wärtsilä and South Korea’s Samsung Heavy Industries (SHI) is exploring battery-hybrid propulsion applications in LNG carriers and shuttle tankers.
- JDP will focus on reducing the number of auxiliary engines onboard LNG carriers and shuttle tankers by replacing them with batteries in a hybrid solution.
- BRL reports that the current order book for LNG carriers is 147 vessels, with 107 under construction in South Korea, 24 in China, 15 in Japan and 1 in Singapore.
As LNG carrier demand increases, operators are turning to battery-hybrid propulsion as a means of reducing operational costs and emissions, reports Marine Propulsion and Auxillary Machinery correspondent John Snyder.
Battery-hybrid propulsion applications
A joint development project between Wärtsilä and South Korea’s Samsung Heavy Industries (SHI) is exploring battery-hybrid propulsion applications in LNG carriers and shuttle tankers, as a means of lowering newbuild costs, fuel consumption and CO2 emissions.
Under an agreement signed at LNG 2019 in Shanghai, Wärtsilä and SHI will share knowledge and experience for the joint development project (JDP).
“We look forward to working with Wärtsilä to co-develop LNG carriers and shuttle tankers with improved efficiency,” says SHI executive vice president, engineering and procurement operations Jin-Taek Jung.
Better efficiency, improved safety, and sustainability
Wärtsilä Marine vice president, processing solutions Timo Koponen agreed, saying the JDP will support greater efficiencies, better environmental sustainability, and improved safety for shipowners.
To lower capital expenditures (capex), the JDP will focus on reducing the number of auxiliary engines onboard LNG carriers and shuttle tankers by replacing them with batteries in a hybrid solution, according to Wärtsilä Corporation general manager, positioning, marine business marketing Marit Holmund-Sund.
The use of batteries should also have a positive impact on operational expenditures (opex) because of reduced fuel consumption and lower engine maintenance costs associated with using fewer engines.
Increase in LNG demand
An important driver for the JDP is the strong global demand for LNG and new LNG carrier tonnage. Increasing LNG demand in China, Southeast Asia, Japan, South Korea, and India is expected to push seaborne cargoes from 308M metric tonnes in 2018 to 478M metric tonnes by 2030.
In turn, the LNG carrier fleet must grow to meet the increased demand. There were 64 new LNG carriers ordered in 2018, compared with only 23 in 2017, according to UK-based BRL Shipping Consultants.
Orders this year are expected to be almost as robust as 2018 with up to 60 new ships, according to shipping research firm Clarkson Research.
BRL reports that the current order book for LNG carriers is 147 vessels, with 107 under construction in South Korea, 24 in China, 15 in Japan and 1 in Singapore. The total capacity on order is 22,222,860 m3.
Greater efficiency, less BOG required
While the JDP will not focus on cargo containment technology, the increase of the overall energy efficiency of the propulsion and auxiliary power machinery would mean that less boil-off gas (BOG) would be required as fuel. “Therefore,” says Ms. Holmund-Sund, “more efficient reliquefication may be the next logical step in connection with our joint development projects.”
For the first four decades of operation, shipowners favored steam turbines for LNG carriers. The early 2000s gave rise to dual-fuel, diesel-electric applications using four-stroke engines as the propulsion of choice.
“The introduction of energy storage systems, decoupling the energy production from energy consumption, is especially beneficial for vessels with more sophisticated trading patterns”.
Improvement of LSDF propulsion system
The current LNG carrier order book tells a different story, with 89 vessels on order with low-speed, dual-fuel (LSDF) power trains, 35 vessels with dual-fuel, diesel-electric (DFDE) propulsion and four vessels with steam turbines and gas engines (StaGE).
The JDP between Wärtsilä and SHI is concentrating on the improved efficiency of standard designs based on LSDF propulsion. “At the same time, we believe that for certain applications our hybrid DFDE will remain a very attractive alternative,” says Ms. Holmund-Sund.
He added, “The introduction of energy storage systems, decoupling the energy production from energy consumption, is especially beneficial for vessels with more sophisticated trading patterns including more terminal calls, waiting and slow steaming. Growth in spot LNG trade will require more of such vessels and our hybrid DFDE is able to provide the needed operational flexibility and additional economy.”
Need for digitalization and efficient data collection
Digitalization will also play a role in improving energy efficiency. “With our data collect unit, we can have full remote and on-line monitoring and control of our installed asset to support the voyage operation,” says Ms. Holmund-Sund. “With the digitalization platform, all data will be available on board, at the fleet center and at the Wärtsilä Expert Centre.”
For the JDP, SHI will oversee any hull and speed optimization. The installed propulsion system is based on a specific trail speed determined by the owner or charterer. The trail speed is still around 19.5 knots, but Wärtsilä has seen some interest to lower the trail speed to 15-16 knots; so far, however, this is not part of the vessel specification. Other areas of hull optimization could focus on air lubrication, trim and route optimization, just-in-time features, and various propeller efficiency devices.
Air lubrication
SHI and Wärtsilä both have their own air-lubrication systems which use an air bubbling system to reduce the friction between the seawater and the ship’s hull, to improve fuel consumption.
In January, SHI won a deal for two 180,000 m3 LNG carriers from Europe’s Celsius Tankers that will be fitted with the shipbuilder’s eco-friendly and smart ship technologies. These will help the ships comply with forthcoming environmental regulations and significantly increase energy efficiency.
One of SHI’s eco-friendly technologies, Saver Air, is an air lubrication system that is expected to save 5% on fuel irrespective of the external environment, such as waves and current.
Intelliman ship solution
In addition, SHI’s own smart ship solution, Intelliman (INTELLIgent & Lifecycle-MANaged) Ship, when applied to the carriers, helps with IMO and European Union emission regulations, such as IMO-DCS and EU-MRV.
Operators can measure and monitor fuel consumption and CO2 emissions for ships in operation on a real-time basis. As accurate operation report can be automatically created based on the accumulated data.
EU – Monitoring, Reporting, Verification regulation
The EU MRV (Monitoring, Reporting, Verification) regulation entered into force on 1 July 2015 and requires shipowners and operators to annually monitor, report and verify CO2 emissions for vessels larger than 5,000 gross tonnages calling at any EU port.
IMO’s fuel Data Collection System (DCS) started on 1 January 2019 and applies to ships of 5,000 gross tonnages and above calling at any port under the jurisdiction of EU member states.
New propulsion and cargo containment cover
Elsewhere, work is underway in Japan on the next generation of LNG carriers. Last year, Diamond Gas Orchid, the first “Sayaringo” StaGE LNG carrier, was delivered to Diamond LNG Shipping, a joint venture between NYK Line and Mitsubishi Corporation. The 165,000-m3 LNG carrier was built by the Nagasaki shipyard of Mitsubishi Heavy Industries (MHI) in Japan. Construction was managed by Mitsubishi Heavy Industries Marine Structure Co., Ltd., an MHI Group company based in Nagasaki. The Diamond Gas Orchid has a length overall of 293.5 m and a beam of 48.94 m.
To reduce ship weight and air resistance, Diamond Gas Orchid has a continuous steel cover that also increases LNG-carrying capacity, according to class society ABS, which worked with Diamond LNG Shipping to develop the vessel design.
“Sayaringo” is a combination of the word “apple” and “pea pod” in Japanese, describing the shape of the Moss-type cargo containment tanks, where the upper semi-sphere is larger than the lower half of the tank and the continuous steel cover. The use of the apple-shaped cargo tanks allows for increased cargo capacity without increasing the ship’s beam, adding to its operational flexibility.
More carrying capacity and less fuel cost
At the time of delivery, ABS senior vice president and chief business development officer Jamie Smith said: “With newly designed cargo tanks and hybrid propulsion, this next generation carrier can carry more LNG and minimize fuel costs.”
One of the newest of the three main types of propulsion for LNG carriers is the hybrid propulsion system StaGE. The idea behind StaGE propulsion is to use the engines’ waste heat in the steam turbines, resulting in a substantial improvement in plant efficiency, enabling high-efficiency navigation throughout a full range of speeds.
Lesser CO2 emissions
MHI reports that the StaGE power plant emits approximately 20% less CO2 emissions than conventional steam turbine plants and that the Sayaringo LNG carrier emits about 40% less CO2 per cargo unit than a 147,000-m3 LNG carrier with conventional steam turbines.
Diamond Gas Orchid and sister vessels Diamond Gas Rose and Diamond Gas Sakura will transport LNG from the US$10Bn Cameron LNG in Hackberry, Louisiana, which is expected to start producing LNG from Phase 1 in Q2 2019. Cameron LNG Phase 1 is jointly owned by affiliates of Sempra LNG, Total, Mitsui & Co, Ltd and Japan LNG Investment, LLC, a company jointly owned by Mitsubishi Corporation and NYK.
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Source: MPropulsion
