Marstec08 -camera Ready Paper- Air Emision Riding Wave Of Technogical Change For Ships F

MARTEC 08 Air Emission, Global Warming Potential and Climate Change, Riding Waves of Technological change for Ships Ab. Saman Abd. Kader1, Mohd Zamani Ahmad 2 Omar Yaakob3, Oladokun Sulaiman4, Shamila Azman5 Machineries – main and auxiliaries that moved the ship are considered as heart of the ship, Climate change and Global Warming which has been recognized as the greatest threat of our generation is linked to ship machineries and this in reciprocal manner driving the wave of technological change for new built and existing ship. This paper will discuss air emission and its inherent consequence of powered shipping, chemical behavior of Green House Gases and evolving mitigation option for retrofitting system for existing ship and new energy technology for new built. Key words: Vessel, Channel, Maintenance, Port Tanjung Pelepas (PTP), Sustainability, Dredging

1

Professor, Ir, Dr., Director of Training ad Education, Malaysian Maritime Academy Associate Professor, University Technology Malaysia 3 Associate Professor, Head of Department - University Technology Malaysia 4 Lecturer , PhD Researcher – Malaysian Maritime Academy 5 Lecturer– University Technology Malaysia 2

1.0 Introduction

The search for a better managed human society and what brought human today threshold of civilization is as whole as man himself. The triple bottom factors of quest for knowledge, the need for production exchange, organizing power of social community – these factors have equally become interrelated and self reinforcing with each advanced technology and organization, scale, trio of energy, economy and environment and matter remaining keys to human civilization; followed by invention of language or ability to communicate, and facilitation of his mobility. All of which went through their course slowly through building stones out of stumbling blocks and some actually amazingly came out through extraordinary revolution. Likewise, all this dynamic changes through differential approach and methods which can be categorized as conventional methods of idea, hypothesis, experimentation and observation. Over the years, time needs, growth, speed, and knowledge and of course scarcity and competition have created demand that necessitated man to build complex institution- all of which require energy to move them. Likewise vast range human development has flown precise measurement of energy and manipulation of delineated discrete object all which has no doubt reduce the crushing boarding of physical work and freed man for other pursuit. Today pollution from energy carry a very large percentage and as the carbon release has exhaust the little oxygen we are sharing and the ozone later that is protecting us from mother due to lack of cogent risk assessment on systems we have been building. More so, because conventional assessment focus more on economics while environment and its associated cycle is put in oblivion, probably because of difficulties associated with uncertainties. For years many think that everything that run air is infinite, the atmosphere and the ocean is providing us source of freshening, winds and current are far more vulnerable to polluting activities that have run off into them too many poisons that the air and the ocean may cease to serve more purpose if care is not taking to prevent pollution. To this end the challenge of air emission is recognized to:

•

Be main inherent consequence of powered shipping

•

Have link to fuel oil burning as main source

•

Have links with continuous combustion machineries - boilers, gas turbines and incinerators

This paper will discuss how the challenge climate change, ozone depletion , global warming touched engineering including engineering requirement of ship operation and the impacts of emission from ship, rising egalitarian techno economic and environmental sustainable abatement method to reduce and control emission. As well as matching development and improvement necessary for energy efficiency and performance of new propulsion system ( all electric ship for short sea shipping and hybrid gas electric system for high sea shipping) through comparison and simulation of extreme conditions. 2.0 Emission Ride on Ship Technology This issue of environment become so sensitive recently with respect to infrastructure development and most especially in everything we use energy for because most of the past polluting activities has turned into poison through point form effect and are presently having advert effect on our in quality of air and water. In a nutshell, the three worlds we live are currently are out of balance and in potential conflict and man is in the middle. Historical records of number of calamity that has resulted to heavy lost and pollution are calling for news and philosophy of doing things through assessment of economics and environmental issue relating to energy, without compromising to the later has a lot of case have been based. This is already equally calling for a number of regulations, that will subsequently affect, policies change and procedures relating to the above and their effect to design of new systems and modification of existing one.

In regards to energy, It all started with environment natural source of energy,-animal, windmill, watermill, then steam, electricity and nuclear, with so much water and wind and even the sun all of which are the primary source of energy that goes through natural circle to support human life and the planet, the remain the leanest inherited resources, new technology has not turn this vast potential income into usable suppliesfor years the

12000 Cox

10000

NOx

8000

CHX

6000

HFC-134a

4000

HFC-227ea

2000

HFC-c-23a CF

0 GWP (100 Year ITH)

Figure 1. - Global warming potential Cleanest and the safest are among the inexhaustible, the use of energy is likened to reckless try and error, experimentation, and age that discover the big gap between renewable and non renewable energy, and how human have adventurism has lead to replacing renewable natural given of nature by non renewable and associated backlash has called for new ways to do things and importance of using advantage of nature and its given. Renewable source of energy range from energy from the sun, hydrogen and biomass- as for the later, using waste to produce biomass is very. reasonable than growing crops that suppose to be used for food to produce energy or else we end up breaking the food chain and when scarcity of products involve come we all have to pay for it anyway. I am not going to discuss much about renewable source of energy or green house gas today. Land based technology will required to be transfer sympathetically to the marine industry via availability of engines, systems and technical assistance. Marine craft operation in inland water operation requires fuel supplied in bulk rendering the NG distribution viable. The use of an alternative fuel for vessel propulsion will leads to a design review of Power plant, associated fuel system and propulsion train; effectively reshaping areas such as Machinery Arrangement, Hull Form, Compartmentation, Cargo Deck, Payloads, Superstructure, Interior Layouts, Escape & Safety, Route Options, etc. Recent environmental revolt from critical like issue of sea level rise, flooding, has brought awareness regarding system failure and reality of uncertainty and point form environmental degradation, which further show that the two world are currently out of balance and in potential conflict and human is in the middle. This call for new philosophy to design system based on risk and goal based holistic sensitivity. Since, it has become obvious that, everything we use on land end their way to the rivers through ground water which then end up to the sea, this make management of water quality, maintaining balance of its purity and preventing substance running into it is a crucial point in protecting the total environment as a result of this International environmental get serious and encourage and call for Galvanize the scientific community by set up panel's /collaborating scientists and technical bodies and encourage use existing scientific bodies and research centers for global observation systems that include taping informal sources of information related to early warning and dealing with problem of sharing sensitive data among countries as well using human capacity and rapid spread of Internet as a tool for information compilation, discussion, and dissemination. Some of the land base regulation that are passed are : • •

(Oil Spills Protocol) - Protocol Concerning Specially Protected Areas and Wildlife (SPAW Protocol) Protocol Concerning Pollution from Land-based Sources and Activities (LBS Protocol)

•

•

•

Agenda 21 To address greenhouse gas emissions from ships- Adoption of control and prevention measures in 2003, as well as problems associated with the transfer of harmful aquatic organisms in ships' ballast water – adoption convention in 2004 to support the International Convention on the Control of Harmful Anti-fouling Systems in Ships 2001; and the diplomatic conference also address implementation of the International Convention on Oil Pollution Preparedness, Response and Co-operation 1990. IMO also get serious and passed MARPOL annex six under a diplomatic confernec and bypassing the usual taxcit procedure . MARPOL cover: Annex I- Oil ,Annex II- Noxious liquid chemicals ,Annex III- Harmful Goods (package), Annex IV- Sewage, Annex V – Ballast water whereby Annex VI- emission and air pollution (SOx, NOx and green house gas, emission of ozone depletion gas (ODG))

Figure 2 – Emission from marine engine - ABS New annex VI to MARPOL focus on : • • • • •

Control and management of Ballast water to minimize transfer of harmful foreign species Global prohibition of TBT in antifouling Coating - phase out scheduled for 2008 International convention on oil pollution, Response and cooperation (OPRC) - 1990 Policy to combating major incidents or threats , control to prevent, mitigates or eliminates danger of marine pollution through port to its coastline from a maritime casualty Annex protocol under this convention (HNS Protocol) covers marine pollution by hazardous and noxious substances (HNS)

Chapter III of Annex VI on the requirements for the control of emission from ships include: Regulation 12- Ozone depletion substances Regulation 13 – NOx Regulation 14 -SOx Regulation 15- Volatile Organic Compounds Regulation 16 – Shipboard Incinerator Regulation 17 – Reception facilities Regulation 18 – Fuel Oil Requirement Regulation 19 – Requirement for platform and drilling rigs

Response to air emission from ships: • • • • • • • • • •

Technical code for prevention of air emissions from ships Diesel engine test Survey Certification of compliance (IAPPC) NOx compliance limit -30% reduction Review of 5 years interval Restriction on use of fluorocarbons on board Carbon dioxide emission from ship Fuel quality SOx Emission Control Areas (SECA)

Requirement for control of emission from ship - Other requirement and standards : • •

•

Fuel grade - ISO 8217 Emission test - ISO 8178 One common limits for all engine - International harmonization of regulation and equipment standards

Thus IMO and the shipping industry got the greatest credit today regarding the way we design and operate , but nonetheless, the value of water and the environment will operate will always require vivid demand for near zero intolerance to discharge or emission Regulation of maritime business and operations has for many year centralized focused philosophy of safer sea and cleaner ocean, however since the protection of marine environment became important international issues pollution of the world ocean augmented to linchpin of international legislation and this is calling all areas of human endeavor to move towards sustainable development. Thus, pollution from shipping only contribute10% of all discharge. Years of marine operation paid little attention to air pollution, IMO declaration for duction under new annex IV MARPOL change this. NOx is given limit of 30% reduction , and sulfur capping of 0.5-5.0% limit, Emissions from oceangoing are forecast to increase 9% to 13% by 2010 and 20% to 29% by 2020, above levels in 2002. Bulk carrier, container and tanker vessels are the three largest contributors. (Fleisher, 1996). Overall energy efficiency should ideally be defined as useful work done in relation to the energy consumption. Thus the efficiency is highly dependent upon the type, size and speed of the ship. Those considerations are generally outside of the scope for this study, although mention will be made when discussing machinery systems that are especially suited for certain types of ship. The interaction of propeller, underwater hull and rudder is important when propulsion efficiency is defined as efficiency in conversion from shaft power to thrust power, this is outside of our scope, consequently under power transmission the study will refer to free running (open water) efficiency of propellers when necessary. .Study conducted by ABS concluded on the following configuration propulsion configurations as best practice hybrid option for large LNG carrier is given below: Table1 – current propulsion configuration- source ABS Slow Speed Engine

Direct drive

Medium Speed Engine

Reduction Gear Electric Propulsion

High Speed Engine and Gas Turbines

Reduction Gear Electric Propulsion

Understanding the basis on which these fuel efficiencies are obtained makes it apparent that the efficiency gained over a conventionally powered vessel will vary according to environmental conditions and vessel use. Prof. Frankel paper on propulsion of LNG also supported this further comparation under emision concluded on the following data: Table 2- Environmental comparison GTE NOx 2 SOx 0 CO 0.1 CO2/100 5

– Source – Prof Frankel DFD 15 6 0.3 4.6

SSD 2 0.3 0.3 4.7

Presently there is need to strengthen efficiency and effectiveness of short sea service towards sustainable distribution and intermodal link from Inland Waterways where is there is potential for future development at places where Inland Traffic originates and terminates from the waterfront.( Frankel, 2006). At a time when the pollution caused by the vehicular traffic is playing havoc with the environment, the ecofriendly mode of transport can be of some help. Hybrid of gas turbine or Diesel with electric couple with dual fuelling that include natural gas, is explorable option for existing trans ocean vessels, while all electric ship using natural gas and microturbine generator are explorable for costal ships. While interesting development for new ship need exploration on technologies to improve integrated full electric propulsion with advanced power management systems: -

Improved converter and power electronics technology Improved generators and motors

3.0 Best Practice Generic Technology Recent time have seen rapid general augmentation of awareness of environmental issues which is creating pressure of need for deeper understanding of engine propulsions system and treatment options, engine modification and new propulsion plant options. Emission restriction have long been imposed on land based power plant by authority, but the advent of green house gas has resulted to extension to marine diesel engine, especially in port and coastal traffic because ship has proved to be a significant contributors of NOx. Sequel to this IMO has passed the long standing resolution Annex IV under MEPC, for new limit to prevent air pollution at sea and coastal water. The research require urgent attention in order to be part of solution to states of the degrading ozone layers, acid rain and smog formation, water quality, detrimental effects on vegetation green house gas global warming and consequential catastrophe issues. Research conducted by Norwegian University of Technology and British Maritime Technology ltd deduced the following Table 3 – Emission and reduction measures category components sources Current of method of reduction Emission COx Machineries/incinerator/boiler from air

SOx

Machineries/incinerator/boiler

NOx

Machineries/incinerator/boiler

HC Noise

Machineries/incinerator/boiler Machineries/cargo operations

Particles HFC/Halon

Machineries/incinerator/boiler Fire extinguisher / refrigeration system Cargo operation

VOC

Low sulfur fuel exhaust washing Exhaust cleaning, engine modification, or input media insulation Sequential loading , vapor return, recovery plant

Table 4 – reduction potentials category components Current reduction potentials Emission COx 1-40% operational planning and speed selection from air 3-7 % efficiency improvement of machineries 70-80 % ( figure uncertain) by limiting the sulfur content in the fuel and / or means of sea water washing NOx 80-90 % by selective catalytic reduction (SCR) 10-30 % by engine turning / injection retarded 20-30 % by engine modification Fuel or injected in cylinder, several alternative methods available with varying reduction potential 30-60 %by sequential loading gas transfer VOC 70-90% by recovery plant The research concluded with recommendation for need to conduct research on technical abatement related to technological energy efficiency and fuel use in fleet.(Morrall 2000) 3.1 Mitigation and Reduction Measures There are 3 ways by which pollution can be controlled • Cleaning fuel prior to combustion (fuel preparation such as fractionation , catalytic cracking , desulphurization ) • Reducing the production of pollutants during combustion ( state combustion, exhaust gas recirculation and reduced temperature level ) • Cleaning exhaust gas All these methods attracts major design modification that heat economic of energy balance

Figure 3- Mitigation and Measures – Source – ABS Primary measures: Use of low sulfur fuel – ( less than 6g/kwh) HFO sulfur content - Need for oil company to change their equipment for low sulfur oil production-> shipowner will face high cost, additive solution has been expensive so far -Reduction of NOx, Sox, + cost saving through boiled off gas reuse.

Secondary measures:

Operationally

Retrofitting for existing engines:

For new engines

-Exhaust gas cleaning system or technology -Sox for SECA (Emission Control Area) & Fuel change over -Nitrogen reduction - through choice of propulsion system

-On board Catalytic system like : Converter, water injection Emulsion -speed reduction (10-20% ) -Use of shore power connection

-Use of NOx injectors -Retarding injection timing -Temperature control of the charge air -Exhaust Gas Recirculation (EGR) -Fuel / water emulsion -Water injection -Humid Air Motor (HAM) Techniqueaddition of wet steam to the engine 50% reduction -Selective Catalytic Reduction (SCR)

Engine certification -Pre-certification, -Technical file clarification on engine family and group, -Final certification

-Sulfur reduction -in bunker fuel -Reliquification plants for LNG/LPG carriers-> - Use of Turbo generator plant –> --PM - SAC volume is the void space in the fuel

Dual fuel option for low sulfur restricted areas ( 1.5-4.5)– need for additional tanks. The content of hydrocarbons in the exhaust gas from large diesel engines depends on the type of fuel, the engine adjustment and design.

Alfa Lubricator system - Reduction in cylinder oil consumption-> reduction in particulate emission -Electronic control engine Programmed fuel injection for exhaust valveEmission reduction - Use of high efficiency air flow

valve downstream of the closing face

for power take off reduce fuel + reduction of emission.

3.2 NOx Technology • Minimizing the NOx emissions from diesel engines is a pressing international problem • In response to this, engine manufacturers are exploring all means of reducing NOx emissions • The graph shows the international regulation standards adopted by the IMO in September 1997

Figure 4 – NOx Compliance limit – Source Yanmar Low-NOx type marine diesel engine for new series engines use the following methods to reduce NOx emissions: NOx depends on : Fuel efficiency, Large bore, Low speed, therefore most mitigation technology when after the above characters to : • NOx is generated when combustion gas is held at high temperature. • To reduce NOx generation, the following steps are required: 1. Lower the combustion temperature. 2. Shorten the combustion time. • Improvements aimed at NOx reduction are: 1. Delay of fuel injection time 2. Use of SCR The IMO NOx emission limit will reduce the average NOx emission factors for ocean-going vessels by 4.1% for main engines and 8.3% for auxiliary engines. The model could help reduced emission from MISC ship further and make MISC ship meet future local and international emission regulation. NOx reduction by means of SCR can only take place in the mentioned temperature window, because if the temperature is too high, NH3 will burn rather than react with the NO/NO2. At too low a temperature, the reaction rate would be too low, and condensation of ammonium sulfates would destroy the catalyst, To reduce the NOx level by up to 98%, it is necessary to make use of the SCR (Selective Catalytic Reduction) technique.

With this method, the exhaust gas is mixed with ammonia NH3 or UREA (as NH3 carrier) before passing through a layer of a special catalyst at a temperature between 300 and 400C, whereby NOx is reduced to N2 and H2O, the reactions are, in principle, the following:

• •

4NO + 4NH3 + O2 → 4N2 + 6H2O 6NO2 + 8NH3 → 7N2 + 12H2O

The amount of NH3 injected into the exhaust gas is controlled by a process computer dosing the NH3 in proportion to the NOx produced by the engine as a function of the engine load. The flexibility of the electronically controlled engine can improve the emission control and operation of NOX reduction by means of water emulsion. When operating with an SCR catalyst, it is difficult to maintain the engine dynamics and the turbocharger stability at transient engine loads. With the electronically controlled engine, a faster load-up by early exhaust valve opening and late injection timing is possible; also, modulated exhaust valve timing stabilizes the turbocharger. EGR system has two water injection stages, with a simple water separator unit after both. The first water injection stage involves humidification with salt water in order to ensure that there is no freshwater consumption in the second freshwater injection stage. The outlet temperature of the first stage is approximately 100oC, this stage has a single multi-nozzle injector. This system is connected to the exhaust system in the same way as the simple EGR system, but the EGR line is routed to a .bubble-bath. scrubber from the which cleans and cools the exhaust gas. the water loop in the scrubber system is cooled and monitored in a Water Treatment Skid with a filter and settling system, cleaning the used sea water.

Figure 5 – SCR Technology The NOx production only takes place at very high temperatures (2,200°K and above), and it increases exponentially with the temperature. The EGR method is based on a reduction of the oxygen content in the cylinder charge, and the HAM method is partly based on reducing the oxygen content of the cylinder charge and partly on increasing the heat capacity of the cylinder charge by the addition of water vapor. The addition of water to the HFO by homogenization increases the viscosity, to keep the viscosity at the engine inlet at 10-15 cSt, max. 20 cSt, It is necessary to raise the temperature to more than the 150oC which is standard today (max. 170oC at 50% water) raise the fuel oil loop. 10% NOx reduction for each 10% water added, the water amounts refer to the injected amount of fuel oil

Figure 6 – NOx reduction performance At increased recirculation amounts; the HC and PM emissions are reduced corresponding to the reduction of the exhaust gas flow from the engine.

Figure 7 - Typical Pressurized Fuel Oil System with Homogenizer 3.3 Sox technology Annex VI to MARPOL 73/78 limits the sulfur content of MFO to 1.5% per mass and will apply in designated SECAs. The first SECA is the Baltic Sea ->enters into force on 19 May 2006. The North Sea Area and the English Channel SECA will enter into force 22 November 2007. The geographical boundaries for these two SECAs are defined in MARPOL 73/78. EU directive 2005/33/EC, requires ships to burn fuel oil with less than 1.5% sulfur in the North Sea SECA from 11 August 2007.) . New SECAs are expected to be adopted in the future based on certain criteria and procedures for designation of SECAs. MARPOL. Annex VI, Regulation 14 (4b) also gives the option of using an exhaust gas cleaning system (EGCS) which reduces the total SOX emissions to 6.0 g/kWh. 3.4 Particulate Matter Technology Reduced sac volume in the fuel valves has greatly reduced PM emissions. Advantage brought by SAC is shown below

Figure 8 – SAC valve for injection performance Alpha lubricator -This involve technology application of high-pressure electronically controlled lubricator that injects the cylinder lube oil into the cylinder at the exact position and time that optimize conventional lubrication lubricators. A parallel line is followed by the SIP (Swirl Injection Principle) lubricator, where the oil is injected prior to piston passage, thereby having the oil distributed by the air swirl. Use for marine engines and engines for power generation purposes, very low feed rates have been demonstrated, with oil consumption down to 0.5 g/bhph. By applying low oil dosage -> emission is lowered + less cylinder oil is wasted in the engine- where it could end up in the system oil, resulting in increased TBN and viscosity.

Figure 9- Alpha Lubricator – Source ABS

Figure 10 –Particulate Matter Measure Performance - ABS The picture above show the use of alpha lubricator reduces lub. Oil consumption and PM. also the filters used for dilution tunnel PM. measurements taken before and after the scrubber at 75% load and 15% recirculation 3.5 Impact of using new fuel • • • •

That technology will transfer sympathetically to the marine industry via availability of engines, systems and technical assistance. Marine craft operation in inland water operation as well as deep sea will require fuel supplied in bulk rendering the NG distribution viable The use of an alternative fuel for vessel propulsion will leads to a design review of: Power plant associated fuel system propulsion train; Effectively reshaping areas such as Machinery Arrangement, Hull Form, Compartment, Cargo Deck, Payloads, Superstructure, Interior Layouts, Escape & Safety, Route Options, etc.

Figure 11 – Fuel efficiency – Source - RINA 3.6 Technology for new built • • • • • • • •

Alternative energy Alternative fuel and dual fuel engines Infusion of water mist with fuel and subsequent gas scrubbing units for slow speed engines Additional firing chamber Potential for gas turbine complex cycle Potential for turbocharger diesel engine Compound cycle with : gasified fuel, external compressor, combustion with pure oxygen Exhaust after treatment for medium speed engines

• Azipod

Exhaust Gas Recirculation Measure performance Best Practice to meet compliance • • •

Lloyd performed a research on exhaust gas emission assessment Roll-Royce built Allen 5000 Series engine with electronics fuel injectors that control NOx Mak engine has developed a new MDS engine with reduction in NOX without fuel penalty

Electric Propulsion Technology The overall power train efficiency with DEP is around 87-90%. Use of permanent magnets in electric generators and motors as well as general advances in semiconductor technology may improve this figure to around 92-95% in the near future. Electrical transmission will consist of three basic energy conversions: -

From (rotating) mechanical energy into electrical energy: E-generator

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From electrical energy into (rotating) mechanical energy: E-motor

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Some form of fixed or controlled electrical conversion in between: power converter

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Simulation, risk assessment and emission quantification are other remain supporting method for decision and selection of new systems.

Electric propulsion system require development of the following technological areas:E-generator The following tree gives a systematic overview of existing types whose improvement will be sought: Mechanical ==> Electrical: E-Generators DC Generators AC Generators E-Motors - The following tree gives a systematic overview of existing types whose improvement will be sough: Electrical ==> Mechanical: E-motors Driving motors Synchronous Motor Positioning motors

Power converters - The following tree gives a systematic overview of existing types: Electrical ==> Electrical: power conversion or transformation Fixed transformers Controlled converters Static converters -Inverter References 1. 2. 3. 4. 5. 6. 7.

8. 9. 10.

11. 12.

13. 14. 15.

16.

IMO (2000) marine environmental protection committee 44th session available at: http: www.imo.org/meeting/44.html R. A Karam and K. Z. morgan, energy and environment cost – benefit analysis: supplement o an international journal , Georgia Institute of Technology , London, 1975 pp. 491-507. N Slocombe, D. S. 1993. Environmental planning, ecosystem science, and ecosystem approaches for integrating environment and development. Environmental Management . Ghai, Dharam and Jessica M. Vivian ,.Introduction., in Dharam Ghai and Jessica M. Vivian (eds.), Grassroots Environmental Action: People.s Participation in Sustainable Development, Routledge, London, 1992, pp. 1-22. D. Stapersma. Diesel Engines: A fundamental approach to performance analysis, turbocharging, combustion, emissions and heat transfer. Part A: Performance analysis"; DUT wb 4408 A / R.Nl.N.C. CC 09; 1996 "The new concept 3-way catalyst for automotive lean-burn engine: NOx storage and reduction catalyst ", Catal. Today 27, 63-69 (1996). Henley,E.J. Kumamoto,H.,1981, Reliability Engineering and Risk Assessment. Prentice- Hall Englewood Cliff, NJ. Kristiansen, S. and Krlsen, J.E., Analysis of Causal Factors and Situation Dependent Factors. Report No. 80-1144,Dets NORSKE Veritas, Hovik, Norway. MSA, 1995, Project 366: Formal Safety Assessment: Draft Stage 1 Report. Marine Safety Agencies, Southampton, February. Safety of Life at Sea Convention, 1974, consolidated edition, IMO London, 1996. International Convention on the Prevention of Pollution at sea, 1973, consolidated edition, IMO London, 1997. Ingemar Palsson, Gert Swenson. Formal Safety Assessment, Introduction of Modern Risk Assessment into Shipping, Report 7594, Swedish National Maritime Administration, SSPA, Maritime Consulting, February 1996. Barn thijsen, 2004 Dual Fuel Electric LNG carrier Propulsion, design and operation of gas carrier ,RINA, UK Murphy, 1996]M. Murphy, Variable speed drives for marine electric propulsion, Trans IMarE, 1996, Vol 108, part 2, pp 97 – 107, [Niini, 1995], M. Niini, J. Laapio Nigel Gee,2002 Power solution for new breed of high speed ro-Ro and Ro Pax Ferries,ship propulsion system