Reducing the emission of GHG

There are different proficient and operational options considered in order to cut down the emanation of GHG by different organisation. The International Council on Clean Transportation made a long list of recommendation that would cut down the GHG emanation ( Appendix I ) , while IMO through the Marine Environment Protection Committee ( MEPC ) identified different classs for the same cause.

On the 9th of April 2009, the ( MEPC ) submitted its 2nd IMO GHG Study. In the survey ( MEPC ) identified four classs of options to cut down ships emanations, these classs are the undermentioned:

Bettering energy efficiency, in other words firing less fuel to accomplish the same end product by optimising the design and operation.

Exploiting renewable energy beginnings ( air current and Sun ) .

Using fuels with less emanations ( biofuels and natural gas )

Using emission-reduction engineerings ( chemical transition, gaining control and storage ) .

Bettering energy efficiency through design and operation:

Optimizing ships design:

The design engineering is considered a short to medium term ; it has to be considered during ships newbuildings, nevertheless some of these optimisations can be applied to bing ships. Each newbuilding has its ain demands, such as ships size and the needed velocity are considered the chief obstruction to accomplish the optimum energy efficiency for the ship. Besides, some ports and river may enforce limitations on the ships draught which further bumping the efficiency.

Optimizing the hull and superstructure:

Although the hull and superstructure may do really small opposition, yet there is still room for more optimisation in order to accomplish better efficiency. Through optimisation of the hull and superstructure minimizes air opposition and drifting, particularly for large container ships which have big superstructures. The latest engineering to cut down the frictional opposition of the hull surface is the air bubble system which blows air bubbles underneath the ship ‘s hull, later cut downing fuel ingestion and bettering fuel efficiency.

Optimizing the Power systems:

This engineering requires retrieving the energy from fumes which can be achieved by utilizing power turbines, this energy can be used to drive a motor to bring forth electricity, and besides it can be used to back up the chief engine. The cured energy can add 10 % to the entire power. On the other manus Diesel-electric propulsion systems provides design flexibleness and accordingly lead to energy economy.

Optimizing the propulsion systems:

Enhancements of the propellor by utilizing propellor vanes, contra-rotating propellors and canals can significantly better the energy efficiency, likewise with utilizing high-efficiency and asymmetric rudders.

Operational efficiencies

Operational alterations such as ( enhanced conditions routing, optimized trim and ballasting, hull and propellor cleansing, better chief and subsidiary engine care and tuning, rushing up ship unloading and slower steaming ) can hold important impact on ships ‘ emanations, The IMO has calculated that a velocity decrease of merely 10 % across the planetary fleet by 2010 would ensue in over a 23 % decrease in emanations.

Energy economy by operations

Fleet direction, logistics and inducements

5.22 Energy efficiency can be improved by utilizing the right ships in a conveyance system.

By and large talking, efficiency will increase if we concentrate ladings in larger ships wherever possible. Naturally, larger ships are non efficient if non adequate lading is available and they have to sail merely partially loaded. Net energy efficiency may be better for a little ship, with entree to more ports and lading types, being able to make full its lading clasp to capacity [ 7 ] .

5.23 Decreases in scheduled velocity ( i.e. accepting longer ocean trip times ) will increase efficiency, but consequence in more ships being needed. However, there is a tradeoff between cargo rates and fuel cost: when cargo rates are low and fuel monetary values are high, it may be profitable to cut down velocity.

Ocean trip optimisation

5.29 Voyage optimisation can be achieved by:

.1 choice of optimum paths with regard to conditions and currents in order to minimise energy ingestion ( weather routeing ) ;

.3 ballast optimisation – avoiding unneeded ballast. Determining optimum ballast is sometimes a hard consideration, as it besides affects the comfort and safety of the crew ; and

.4 trim optimisation – determination and operating at the right trim.

5.31 Weather routeing can ensue in significant nest eggs for ships on certain paths. Several types of conditions routeing systems, proficient support systems, public presentation monitoring systems and other systems can be used to assist accomplish optimum ocean trip public presentation.

Energy direction

Certain ladings, such as particular petroleum oils, heavy fuel oils, bitumen, etc. , require warming.

Some of this heat can be supplied by bring forthing steam, utilizing heat from the fumes. However, in many instances an extra steam boiler is needed to provide sufficient steam. Steam from fumes gas is by and large sufficient to heat the heavy fuel oil that is used on most ships ; in port, nevertheless, steam from an subsidiary boiler may be needed.

5.35 It is frequently possible to cut down energy ingestion on board by working towards more witting and optimum operation of ship systems. Examples of steps that can be taken include:

.1 turning away of unneeded ingestion of energy ;

.2 turning away of parallel operation of electrical generators ;

.3 optimisation of steam works ( oilers ) ;

.4 optimisation of the fuel clarifier/separator ;

.5 optimized HVAC operation on board ;

.6 cleaning the economizer and other heat money changers ; and

.7 sensing and fix of leaking steam and compressed-air systems, etc.

Upgrading mechanization and procedure control, such as automatic temperature control, flux control ( automatic velocity control of pumps and fans ) , automatic visible radiations, etc. , may assist to salvage energy. The energy-saving potency of energy-management steps is hard to measure, as this depends on how expeditiously the vas was already being operated and on the portion of subsidiary power ingestion in the entire energy image. A economy of 10 % on subsidiary power may be realistic for many vass. This corresponds to ~1-2 % of entire fuel ingestion, depending on fortunes.

5.37 Optimum care and tuning of chief engines.

5.38 Keeping a clean hull and propellor is of import for fuel efficiency.

Choice of more effectual hull coatings.

16. Reducing the velocities at which ships travel is frequently seen as a “ speedy win ” in footings of cut downing C emanations from ships.

New surveies show that many abatement engineerings are available, and cost-efficient such as:

Slide valves cut down NOx on slow slow-speed engines by 20 % , really inexpensive, easy to suit & amp ; cost cost-efficient.

In-engine controls could cut new engine NOx by 30 % .

Water Injection / Humid Air Motor cut 50 % / 75 % .

Sea-water scouring cuts SO2 by 75 % .

Selective Catalytic Reduction cuts NOx by 90 % .

air current and Sun:

Renewable energy beginnings

5.39 Renewable energy can be used either straight on board ships ( by using air current, solar and beckon energy ) or energy can be generated on-shore and converted into an energy bearer such as H or electricity.

Wind power, onboard usage

5.40 Wind power can be exploited in assorted ways as the motor power for ships, for illustration by:

.1 Traditional canvass ;

.2 Solid wing canvass ;

.3 Kites ; and

.4 Flettner-type rotors.

5.41 These systems have different features. Wind conditions differ between parts, so that air current power is more attractive in certain parts and paths than in others. This survey indicated that the potency for canvas energy was better in the North Atlantic and North Pacific than in the South Pacific. Fuel nest eggs were somewhat greater at higher velocities.

However, in footings of per centums, the fuel nest eggs were greater at low velocity, due to the low entire demand for propulsion power. In per centum footings, nest eggs were typically approximately 5 % at 15 knots, lifting to about 20 % at 10 knots.

5.42 Contemporary experience of all of these engineerings on board big vass is limited, and patterning consequences are hence hard to verify. Nevertheless, wind-assisted power appears to hold possible for fuel-saving in the medium and long term.

5.4 Wind and solar energy could besides lend to reducedCO2 emanations, but as a auxiliary beginning of energy instead than a entire supplier. Nuclear propulsion has been successfully used in naval vass.

Solar power, onboard usage

5.43 Current solar-cell engineering is sufficient to run into merely a fraction of the subsidiary power demands of a oiler, even if the full deck country were to be covered with photovoltaic cells.

Naturally, at certain times and in certain countries, solar radiation will be above norm and the subsidiary demands for power could be met. Furthermore, since solar power is non ever available ( e.g. , at dark ) , backup power would be needed. Therefore, solar power appears to be of involvement chiefly as a complementary beginning of energy. With present engineering it could be possible to salvage merely a few per centum of entire energy demands, even with extended usage of solar power.

However, contemporary cost degrees and efficiency topographic point solar power towards the lower terminal of the cost-effectiveness list [ 9 ] .

Wave power, onboard usage

5.44 This includes constructs for using moving ridge energy and/or ship gesture. Examples include internal systems ( gyro-based ) and external systems such as wavefoils, austere flaps or comparative motion between multiple hulls ( trimarans ) . These systems have high proficient complexness, limited possible energy efficiency and are non regarded as being really assuring.

Renewable energy from shore

5.45 Renewable energy is generated onshore from air current turbines, hydroelectric strategies, geothermic workss, solar energy workss, etc. Potentially, energy from such beginnings could be used to power ships if a suited energy bearer was available. However, every bit long as there is a deficit of renewable energy onshore, there is small to be gained by directing shore-based renewable energy to transport propulsion. A noteworthy exclusion is the usage of shore power when a ship is berthed.

15. Fuel cells, solar-power, air current kites etc are all theoretically possible alternate engineerings, but they are best viewed as auxiliary power beginnings instead than options to the chief propulsion systems on board.


14. Alternate fuel beginnings may besides hold a function to play and bio-fuels can be used in ships engines. However, given the volume of fuel used by the transportation industry and the current uncertainness environing the net benefit of bio-fuels, the industry would see it prudent for legislators to better measure the impact of a significant take-up of bio-fuels by such a big consumer as international transportation before making any determinations.

5.2 Existing propulsion systems with C based fuels are likely to be the lone realistic big volume fuel for transportation over the following 20 old ages and likely longer.

Natural gas is presently the forepart smuggler in footings of a lower C fuel for the short-medium term, either as liquified natural gas ( LNG ) or compressed natural gas ( CNG ) .With presently available propulsion machinery, usage of natural gas could accomplish around 20 % decrease in CO2 emanations compared to residual or diesel oil fuels.

5.3 In the longer term, H could emerge as a feasible solution. Sustainable biofuel may besides hold a function to play if sufficient fuel were to be made available to transporting. Alternatively, radically new fuels and/or engineerings may emerge to play an of import function.

Fuels with lower fuel-cycle CO2 emanations

5.46 Emissions of CO2 can be cut by exchanging to fuels with lower entire emanations through the full fuel rhythm ( i.e. production, refinement, distribution and ingestion ) . The switch from utilizing residuary fuels to distillate fuels that is implied by the sulfur ordinance in the revised MARPOL Annex VI has already been agreed ; hence, there is no ground to discourse the possible virtues and demerits of this move on the emanation of CO2 here. Other fuel options with possible benefits for cut downing the production of CO2 include biofuels and natural gas.


5.47 Contemporary biofuels ( frequently referred to as “ first-generation ” biofuels ) are produced from sugar, amylum, vegetable oil, or carnal fats. Many of these fuels can readily be used for ship Diesels with no ( or child ) version of the engine. First-generation biofuels can be upgraded ( hydrogenated ) in a refinery. In this instance, the ensuing fuel is of high quality and the aforesaid practical jobs do non use. This upgrading costs energy, and therefore consequences in extra emanations.

5.48 The net benefits on emanations of CO2 differ among different types of biofuels. Not all biofuels have a CO2 benefit. Use of biofuels has in certain instances resulted in a 7 % to 10 % addition in the NOx emanations.

5.51 In sum-up, the present potency for cut downing emanations of CO2 from transporting through the usage of biofuels is limited. This is caused non merely by engineering issues but by cost, by deficiency of handiness and by other factors related to the production of biofuels and their usage. Additionally, the biofuels are, at present, significantly more expensive than crude oil fuels.

Liquefied natural gas ( LNG )

5.52 Liquefied natural gas can be used as an alternate fuel in the transportation industry. The fuel has a higher hydrogen-to-carbon ratio compared with oil-based fuels, which consequences in lower specific CO2 emanations ( kilogram of CO2/kg of fuel ) . In add-on, LNG is a clean fuel, incorporating no sulfur ; this eliminates the SOx emanations and about eliminates the emanations of particulate affair. Additionally, the NOx emanations are reduced by up to 90 % due to cut down peak temperatures in the burning procedure. Unfortunately, the usage of LNG will increase the emanations of methane ( CH4 ) , therefore cut downing the net planetary heating benefit from 25 % to approximately 15 % .

5.54 One of the chief challenges for the usage of LNG as a fuel for ships is to happen sufficient infinite for the onboard storage of the fuel. At the same energy content, LNG has a volume 1.8-times larger than Diesel oil. However, the bulky force per unit area storage armored combat vehicle requires a big infinite, and the existent volume demand is in the scope of three times that of Diesel oil.

Conversion from Diesel propulsion to LNG propulsion is possible, but the LNG is chiefly relevant for newbuildings since significant alteration of engines and allotment of excess storage capacity is required.

5.56 In sum-up, the present potency for decrease of emanations of CO2 from ships through the usage of LNG is slightly limited, since it is chiefly relevant for newbuildings and because, at present, LNG bunkering options are limited.

The monetary value of LNG is soon significantly lower than that of distillation fuels, doing an economic inducement for a move to LNG.

With regard to alternate fuels, merely liquefied natural gas is a serious rival for replacing traditional fuels. The complexness of on vas storage and containment systems and the shore-side substructure required for resupply badly limits the acceptance of this fuel. The operational scope of vass utilizing LNG is limited by the fuel armored combat vehicle size and boil off rates. LNG is considered by industry to be more suited for short sea traffic than the deep sea trade. Indeed, some ferry paths with dedicated supply and shore-side substructure in Scandinavia presently use LNG for chief propulsion fuel.

The transportation industry is a diverse one, and provides many different services to society.

Nuclear power is technically executable for ships and there are illustrations of nuclear-powered merchandiser every bit good as military ships. Issues of security and acceptableness are, of class, dominant in that peculiar argument. Nuclear propulsion requires a particular substructure and exigency response capablenesss. Added to general social frights, it is non considered that atomic propulsion will play a important function in merchandiser ships. Nuclear power, although proven to work in the sixtiess, would non be commercially feasible or socially acceptable. If atomic power was to be considered it may be more acceptable and efficient to utilize this power to synthesize marine fuels on shore. Lenin

The tabular array below from IMO Bulk Liquid Gases Report, p 16, December 2007.According to research commissioned by the IMO, engineerings could cut down fuel ingestion and oil use by up to “ 30-40 % ” .

However, some of these steps have been adopted by industry and consequences have reportedly non been run intoing outlooks.

There are non-conventional engineerings presently being appraised for pertinence, such as the sky canvas construct, duplicate propellor and the under hull air shock absorber.

The developer of a kite system asserts their system may cut down a ship ‘s fuel ingestion by 10-35 % on one-year norm, depending on air current conditions. Although recent trials have the grade at the lower terminal of the spread. Under optimum air current conditions, fuel ingestion can temporarily be reduced by up to 50 % .

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Emission-reduction engineerings

5.57 Although it is possible to take CO2 from exhaust gases by chemical transition, this is non considered executable. Emission-reduction engineerings are chiefly relevant to pollutants within exhaust gases, NOx, SOx, PM, CH4, NMVOC.

Emission-reduction options for NOx

5.58 Emissions of NOx from Diesel engines can be reduced by a figure of steps, including:

Fuel alteration.

Alteration of the charge air.

Alteration of the burning procedure.

Treatment of the fumes gas ( selective catalytic decrease SCR ) .

5.59 The sulfur content and the deposit-forming inclination of a fuel influence the possibilities for other emission-reduction engineerings, such as fumes gas recirculation ( EGR ) or selective catalytic decrease ( SCR ) . Consumption and pureness of H2O are issues with all options that use H2O.

5.61 The usage of LNG as a fuel is both a switch of fuel and a alteration in the burning procedure.

5.62 decrease of 15-20 % NOx from the current degrees, can be achieved with alterations of the internal-combustion procedure. At present, decrease of emanations of NOx to Tier III bounds ( ~80 % decrease ) can merely be achieved by selective catalytic decrease ( SCR ) post-treatment or by utilizing LNG and thin premixed burning.

Emission-reduction options for Sox

5.65 exhaust-gas scouring system can be employed to cut down the degree of sulfur dioxide ( SO2 ) . Two chief rules exist: open-loop saltwater scrubbers and closed-loop scrubbers. Both scrubber constructs may besides take PM and limited sums of NOx.

Scrubing of exhaust gases requires energy, which is estimated to be in the scope of 1-2 % of the MCR.

5.66 Scrubing to take SOx reduces the temperature of fumes gas. On the other manus, SCR engineering requires high temperatures of fumes gas and at the same clip creates low sulfur and PM content in the fumes gas. Uniting SCR with scouring to take SOx is therefore non considered executable.

5.67 Pollutant stuff that is removed from the fumes is carried in the wash H2O.

Sulphur oxides react with the saltwater to organize stable compounds that are usually abundant in saltwater and non believed to present a danger to the environment in most countries. On the other manus, particulate affair in the fumes that is trapped in the saltwater may be harmful to the environment. The revised IMO Scrubber Guidelines [ 31 ] provide bounds for the wastewater, including bounds for Polycyclic Aromatic Hydrocarbons ( PAH ) , turbidness, pH, nitrates and other substances. Port State demands for outflowing discharges will hold a important impact on the possible usage of saltwater scrubbers. To carry through these demands, it will be necessary to put in a intervention system to clean the wastewater. By and large, the more SOx and PM that is removed from the fumes by the scrubber, the more pollutant will hold to be removed from the wastewater.

Emission-reduction options for PM

5.70 Some emanations of PM from high-sulphur fuels can be reduced by scouring with saltwater. Claims for the possible decrease of PM degrees range from 90 % to 20 % , depending on beginning. With low-sulphur fuels, emanations of PM can be farther reduced by optimising burning to accomplish increased oxidization of carbon black and of PM, minimising ingestion of lube oil and minimising the usage of additives in lube oil. The combustion of fuel-water emulsions can besides cut down emanations of PM to a certain extent.

Emission-reduction options for CH4 and NMVOC

5.72 Engine exhaust emanations of methane ( CH4 ) and Non-methane volatile organic compounds ( NMVOC ) are relatively low. Some decreases may be achieved by optimising the burning procedure. NMVOC may besides be oxidized with a accelerator. Oxidation accelerators are non uncommon in concurrence with SCR installings, where they oxidize fresh ammonium hydroxide, therefore extinguishing emanations of ammonium hydroxide.

5.73 Emissions of CH4 By careful design to avoid crannies, emanations can be significantly reduced. However, there will be a staying degree of CH4 emanations. This CH4 can be oxidized by utilizing a accelerator, although this is non every bit simple as cut downing the degrees of NMVOC, and this is an country for research and development.

5.74 Emissions of CH4 from gas engines can be virtually eliminated by replacing the construct of thin premixed burning with high-pressure gas injection. This latter construct is believed to be good for big two-stroke engines. The disadvantage of this option is that the decrease of NOx emanations that is achieved through direct injection is less than can be achieved with thin premixed burning.

Options for cut downing emanations of HFC and other refrigerants

5.75 Emissions of Hydrofluorocarbons ( HFC ) are related to leaks during the operation and care of infrigidation workss. Technical steps to cut down leaks include designs that are more immune to corrosion, quiver and other emphasiss, cut downing the impact of leaks by cut downing the refrigerating charge ( i.e. by indirect chilling ) , and compartmentalising the piping system, so that a escape may be isolated.

Appraisal of possible decrease of emanations

Potential for decrease of CO2 emanations

5.76 A figure of options for betterments in efficiency have been discussed in old paragraphs. The possible for salvaging energy by uniting these options is really important.

On the other manus, costs, deficiency of inducements and other barriers prevent many of them from being adopted. Therefore, when doing an appraisal of the possible economy, we besides make inexplicit premises sing the grade of via media, attempt and excess costs that would be required.

An appraisal of energy-saving potencies, utilizing known engineering and patterns, is shown in table 5-2. The scopes in the figures in this tabular array show the fluctuation in possible for different ship types and the grade of committedness to doing nest eggs.

5.77 Premises of future betterments in efficiency are used in the future emanations scenarios presented in chapter 7. The high figures shown in table 5-2 correspond reasonably good to the scenario with the highest betterment in energy ingestion, in which net betterments, excepting the usage of low-carbon fuels, scope from 58 % to 75 % , depending on the ship type, in 2050. This premise, every bit good as indexs of historic conveyance efficiency for different ship types, is illustrated in figure 5-1. The background of the coevals of historical efficiency informations is presented in chapter 9.

Appendix I

The International Council on Clean Transportation recommendations to cut down the GHG ( )




– Short term:

A° Lower fuel S degree in SOx Emission Control Areas ( SECAs ) from 1.5 % to 0.5 % .

A° Include SOx /PM related wellness effects in add-on to impacts on air, sea, and land as justification for SECA.

A° Expand SECA plan to high ship-traffic countries in Mediterranean, Pacific Rim and North Atlantic.

A° Regional bounds in coastal countries, inland waterways, and at ports.

– Medium term:

0.5 % sulfur fuel globally

– Long term:

Harmonization with on-road Diesel fuels ( 500 ppm to 10-15 ppm over clip )

– International criterions ( IMO )

New engines

– Short term:

A° NOx criterions 40 % per centum below current IMO criterions ( 2000 degree ) .

A° PM criterions

A° Encourage new engineering presentation.

– Medium term:

A° NOx criterions 95 % per centum below current IMO criterions ( 2000 degree )

A° PM criterions further reduced

A° Encourage new engineering presentation

– Long term:

Promote the usage of advanced engineerings, particularly near-zero emanation engineerings in promising applications.

– International criterions ( IMO )

New vass

– Short term:

A° Adopt international demands for shore power standardisation.

A° All new ships built with shore-side electricity capableness particularly cruise ship and ferries.

– Long term: Promote the usage of advanced vas design constructs in promising applications

– Preferential catching of cleanest bearers.

– Environmentally differentiated fees and charges.

– International ordinance ( IMO ) .

Existing vass and engines

– Short term:

A° Adopt emanations public presentation criterions by vessel category and engine features based on demonstrated retrofit potency.

A° Study feasibleness and possible impact of plans to advance early ship retirement and environmentally sound disposal.

– International criterions ( IMO )

– Preferential catching of cleanest


– Environmentally differentiated fees and charges.


– Short term:

A° Develop GHG emanation stock list and fleet baseline

A° Market-based steps for vass.

A° Implement fuel economic system criterions by vessel category and engine features for new vass.

– Medium term:

Implement fuel economic system criterions by vessel category and engine for bing vass.

– Preferential catching of cleanest


– Environmentally differentiated fees and charges.

– Cap and trade plan for transporting sector merely.

– International criterions ( IMO ) .

At port

– Short term:

Select scheme that provides

maximal emanations decrease benefits depending on local fuel handiness and environmental public presentation of electricity


A° Shore-side electricity

A° Lowest S on-road fuel and NOx and PM after-treatment.

– Medium term: Market-based steps to advance low- or non-carbon energy beginnings to provide shore-side electricity for docked ships

– Port authorization demand.

– Preferential catching of cleanest


– Environmentally differentiated fees and charges.