Inaugural ‘gas fuelled ships’ conference a resounding success

The event was ably chaired by John Aitkin, the secretary general of SEAaT (Shipping Emissions Abatement and Trading) who, in his opening welcome remarks, emphasised the growing importance and impact that liquefied natural gas (LNG) is having on the shipping industry.

The tone of the conference was set by the keynote speech from Dr Pierre C Sames, senior vice president strategic research and development at Germanischer Lloyd, entitled ‘Attractions to using gas as a fuel and challenges ahead’. Dr Sames outlined that gas as ship fuel offers not only considerable opportunities but that there are challenges ahead before this technology becomes widely used. “The motivation to consider using gas as ship fuel has become stronger and we are now reaching a phase which requires more focus on the gas-as-fuel supply and bunkering as well as selecting the right gas storage tank size and type,” he said.

Principles of LNG for ships

A busy programme comprising some 13 informative and technical presentations was kicked off with the first session which examined the principles of LNG as a fuel for ships. The first paper on fundamentals, benefits and operational issues of LNG-powered ships from an engineering perspective was presented by Joseph Morelos from Lloyd’s Register. He provided an insight on the relative pricing between oil and LNG showing the comparison in amounts of energy derived from these fuels. Flammability, ignition properties, distribution of gas supplies and the hazards associated with natural gas storage were examined in detail. He concluded that, despite its current abundance, gas should be regarded as a stop-gap fuel until renewable energy sources can be fully developed and that, in the meantime, shipping should embrace LNG as a clean and economical source of energy.

The second paper was from Lars Petter Blikom of Det Norske Veritas which looked at the economical comparison of different alternatives for compliance with ECA emission regulations. To illustrate the economic viability of LNG, he cited the example of a conversion feasibility study carried out on a passenger vessel operating in the Baltic Sea. The study concluded that it was technically feasible and that all class criteria can be met even though the placing of the LNG tanks was a major issue. Blikom concluded by stating that LNG is the way forward for the shipping industry and all it needs now is for shipowners to rise to the challenge and switch to natural gas.

Bunkering and infrastructure

The second session focused on bunkering and infrastructure and the opening paper was presented by Benjamin Scholz from the process and gas technology group at Germanischer Lloyd. He dealt with the technical challenges and perspectives of bunkering LNG fuelled vessels using as an example a gas fuelled cruiseship. Although the IGF Code includes requirements regarding bunker stations, it does not address procedures for bunkering or the bunker vessel itself which should be regulated in the same way as LNG terminals.

Next was Jurgen Harperscheidt of TGE Marine Gas Engineering GmbH to talk about LNG fuel shipboard systems and infrastructure for ships other than LNG carriers. TGE has been developing several studies on this issue by transferring experience gained from LPG/ethylene carriers to LNG ships. With a containment system based on IMO type C tank, TGE could provide cylinder tanks up to 10,000m³ or bilobe tanks up to 20,000m³ for large 75,000m³ feeder LNG carriers to supply satellite terminals. Safety measures will have to be developed together with improved insulation for ships other than gas carriers in order to bring LNG handling as close as possible to that of liquid fuels.

This was followed by a presentation on gaseous fuels for propulsion, rules, key safety considerations and main challenges, by Yannis Calogeras from Bureau Veritas marine division. While technical solutions to install gas fuelled engines in vessels are in place and IMO and class societies have developed rules and regulations on natural gas propulsion of ships, logistical and infrastructure issues have yet to be solved. However, persuading governments to provide assistance with the development of the required infrastructure and create economic incentives for shipowners is a major obstacle.

Fuels and fuel supply

The next session looked at the fuel supply issue and was kicked off by the keynote speaker, Dr Pierre Sames of GL, with a paper on the expected demand for LNG as ships’ fuel in Northern Europe. With the upcoming strict emission limits for shipping in emission control areas (ECAs), interest in new technology to meet this challenge has increased recently. Essentially three options exist to reduce SOx emissions: the use of low sulphur diesel fuel; the use of exhaust gas treatment systems; and the use of alternative fuels such as LNG. The latter has recently become more commercially attractive compared even with residual fuels and Dr Sames proceeded to give predictions of LNG demand in the Baltic Sea ECA up to the year 2020 which suggests that the absolute LNG demand remains limited. He concluded that investment in mobile LNG infrastructure seems a more logical first step than aiming at fixed LNG storage hubs in ports.

Giulio Tirelli from Wärtsilä was next with a paper entitled ‘Go for Gas’ in which he advocates that the only viable solution to the increasingly stringent emission regulations is to switch to natural gas. Because fuel flexibility gives owners a chance to select the most suitable fuel to meet local requirements, dual-fuel engines make economic sense and, in response, Wartsila has developed the LNGPac, a modularised, complete system for onboard gas fuel storage and handling. This equipment is optimised for integrated operations with Wärtsilä’s dual-fuel engines and Tirelli announced that the first Wärtsilä LNGPac system will be installed on the 25,000 dwt product tanker Bit Viking which will be converted to LNG propulsion by mid 2011.

This was followed by Audun Brandsaeter from DNV with a presentation on safety issues of LNG powered ships. Although no major accidents have occurred in the transportation and use of LNG in the shipping industry, international regulations need to be put in place with the aim to have one set of rules able to cover all vessel types and engine configurations. These would need to include systems to guard against explosive atmosphere in the engine room while gas storage and bunkering arrangements must be subject to adequate controls and a recognised, standardised way of performing ship to ship LNG bunkering in port needs to be agreed upon.

Concluding this session was Viola Pokman who is currently working on her diploma thesis at Marine Services GmbH in Hamburg on the topic of design of an LNG tank regarding boil-off gas. In a highly technical and detailed paper, Pokman examined the different types of insulation for LNG tanks and the resulting heat impact to the tank which leads to increasing the tank temperature and boil-off gas which in turn affects the methane content of the natural gas. Gas engines need a certain methane number to avoid knocking and it is therefore essential to optimise the insulation to ensure safe engine operation. Using as her example the LNG type C fuel tank onboard a ro-ro vessel, Pokman found that all three types of insulation were capable of optimising the tank and that the final selection would depend on individual operational requirements.

Ship and propulsion system design

Ship and propulsion system design was the theme for the final session and opened with a presentation on the vessels propelled by gas engines driving controllable propellers through mechanical transmission by Ivar Brekke Flusund of Rolls-Royce Marine. Regulatory, economic and technical aspects of this type of propulsion were dealt with in great detail and Flusund also gave a review on the development of a new series of marine engines for LNG fuel together with a new power electrical system, the hybrid shaft generator. He maintained that a spark ignition lean-burn gas engine offers efficiency over a much wider load range and, when combined with a HSG supplying electrical power, the performance would be improved even further.

Next was James Bennett from Austal who dealt with the application of LNG as a fuel for medium and high speed ferries. With the increasingly demanding environmental regulations as well as higher fuel prices, particularly distillate fuel, the high speed sector has been under pressure to develop new ferry platforms that can combine the advantages of light weight aluminium construction with LNG. Added pressure on operators is coming from IMO’s work in developing an Energy Efficiency Design Index (EEDI) and their plans to roll out an Energy Efficiency Operational Index (EEOI) for ships.

Over the last 18 months Austal has been researching the development of several new types of fast ferries, the most promising of which are the multi-hulled vessels that comply with the High Speed Craft code (HSC) but are significantly slower than traditional high speed ferries. Austal is confident that it is in a position to offer LNG as an alternative solution, possibly by using dual fuel gas turbines connected to waterjets via a reduction gearbox.

The third paper on the feasibility and economical aspects of gas-fuelled container feeders was presented by Friedrich Wirz from MAN Diesel & Turbo. Although many of the technical issues associated with LNG fuel for ships have been solved, there remains the challenge to integrate the various components into an integrated system and its incorporation into the design of a vessel. This is why MAN has undertaken a study in collaboration with GL, TGE Marine and Neptun Stahlkonstruktion to assess the technical and economic feasibility of installing a LNG-based propulsion system into a container feeder vessel. Using the most stringent emission limitations of the ECAs, the study selected an existing diesel powered design, the Neptun 1,200 TEU, suitably amended for LNG as a future newbuilding project.

It was found that it is technically feasible to install an LNG-based propulsion system, with an acceptable impact on cargo space and deadweight. A reasonable payback time could be realised based on fuel price projections, although the fuel price scenario is highly volatile.

The final paper of the conference was delivered by DongKyo Choi from Daewoo Shipbuilders & Marine Engineering on LNG fuelled large commercial vessels. While there are a number of small offshore and coastal based vessels operating in northern Europe with LNG fuelled engines, Choi believed that more attention should be paid to developing large deep-sea LNG fuelled cargo carrying ships. DSME has been working on this project for several years looking at design aspects for main and auxiliary engines, fuel gas supply systems and LNG storage tanks.

Using the ME-GI two stroke dual fuel engine from MAN Diesel, DSME has developed and patented the HiVAR fuel gas supply system which is claimed to enhance the overall efficiency of the engine. This system can also be used with dual fuelled gensets without any major modification. DSME has also developed an IMO type B prismatic shaped LNG bunker storage tank which is more space efficient than cylindrical tanks. The cost effectiveness of these systems onboard a 14,000 TEU container ship was evaluated and, as a rough estimate, the payback period would be not more than three to four years. The LNG bunkering infrastructure can be taken care of by ship to ship transfers using small 40,000m³ LNG carriers or terminal facilities.

The conference concluded with a lively question and answer session followed by the chairman’s summary in which he stressed the value and usefulness of the event which was followed by a networking drinks reception.

This first event was sponsored by Germanischer Lloyd, Rolls-Royce, Wärtsilä, Bureau Veritas and Marine Service GmbH.