A comparative assessment with focus on environmental impact

Original Article

Proc IMechE Part M:J Engineering for the Maritime Environment2014, Vol 228(1) 44–54� IMechE 2013Reprints and permissions:sagepub.co.uk/journalsPermissions.navDOI: 10.1177/1475090213480349pim.sagepub.com

Fuels for short sea shipping: Acomparative assessment with focuson environmental impact

Selma K Bengtsson1, Erik Fridell1,2 and Karin E Andersson1

AbstractShort sea shipping is facing harder requirements on exhaust emissions in the coming years as stricter regulations areenforced in some regions of the world. In addition, shortage of conventional fuels as well as restrictions on greenhousegas emissions makes the search for new fuels of interest. The objective of this article is to assess important characteris-tics to evaluate when selecting fuels for short sea shipping. The following four criteria are considered: (1) local andregional environmental impacts, (2) overall environmental impact, (3) infrastructure and (4) fuel cost and competitionwith other transport modes. Special focus is put on environmental impact, and life cycle assessment is used for the envi-ronmental assessment. The fuels compared in this study are heavy fuel oil, marine gas oil, biomass-to-liquid fuel, rape-seed methyl ester, liquefied natural gas and liquefied biogas. This study shows that liquefied natural gas will reduce thelocal and regional environmental impacts more relative to the other fuels investigated here. Furthermore, liquefied bio-gas is found to be the most preferable if all environmental impact categories are considered. This study also highlightsthe importance to consider other impact categories for short sea shipping compared to deep sea shipping and showsthat NOX emission is the dominant contributor to all assessed environmental impact categories with local and regionalimpacts.

KeywordsShort sea shipping, fuels, criteria, life cycle assessment

Date received: 3 October 2012; accepted: 11 January 2013

Introduction

Short sea shipping is promoted as an efficient and effec-tive complement to road freight transportation. It isgenerally viewed as more energy efficient and less pol-luting than road freight at the same time as it can helplimit road congestion.1–3 However, some questionsregarding its environmental performance compared toroad freight transportation modes have been raisedlately.4,5 Short sea shipping is facing harder requirementson exhaust emissions and fuel quality in the coming yearsas stricter regulations are enforced in different regions ofthe world together with a pressure to reduce the emis-sions of greenhouse gases. The regulations for emissionsof sulphur dioxide (SO2) are today stricter in special areascalled Sulphur Emission Control Areas (SECAs) that arefound in the Baltic and North Seas as well as along theNorth American coastline. In the near future, the sulphurregulations are tightened further in these areas, and thereare also stricter regulations for emission of nitrogen oxi-des (NOX) in corresponding NOX Emission Control

Areas (NOX ECAs) (at present only the North Americancoastline). In order to comply with the coming regula-tions, vessels within ECAs must change fuel and/orimplement exhaust abatement equipment.

Today, heavy fuel oil (HFO) is the dominant ship-ping fuel and the sulphur content is usually 1% orabove on mass basis. Two fuels that fulfil the SECAregulation in 2015 (maximum of 0.1% sulphur on amass basis) are marine gas oil (MGO) and liquefiednatural gas (LNG). It is also possible to continue theuse of high-sulphur HFO in combination with a scrub-ber that removes SO2 from the exhaust gas. In order to

1Department of Shipping and Marine Technology, Chalmers University of

Technology, Gothenburg, Sweden2IVL Swedish Environmental Research Institute, Gothenburg, Sweden

Corresponding author:

S Bengtsson, Department of Shipping and Marine Technology, Chalmers

University of Technology, SE-412 96 Gothenburg, Sweden.

Email: [email protected]

at PENNSYLVANIA STATE UNIV on March 5, 2016pim.sagepub.comDownloaded from

http://pim.sagepub.com/

comply with the NOX ECA regulation (Tier III), amaximum emission of 2–3.4 g NOX per kilowatt hour(dependent on the engine speed) is allowed for shipsconstructed after 2015. This will require either the useof fuel/engine technologies with low inherent emissionsor the use of NOX abatement techniques. This legisla-tion will, however, only slowly lead to reduced NOX

emissions as new ships are replacing old ones.When evaluating the environmental aspects of fuel

choices, the full life cycle should be considered, startingfrom the extraction of raw materials, through productionand distribution to final use for transportation. The inter-est in the life cycle performance of marine fuels is increas-ing, and some studies have been published on thematter,6–9 but none of these have focused on short seashipping and the environmental impacts that are mostimportant for this segment. The short sea shipping seg-ment has different characteristics compared to deep seashipping, which may affect the choice of fuels. The objec-tive of this article is therefore to assess what characteristicsare important to evaluate when selecting fuels for shortsea shipping with special emphasis put on environmentalcharacteristics. In order to illustrate this, seven fossil andbiogenic fuels are compared against a set of criteria reflect-ing the conditions for the short sea shipping segment.

Method

This section identifies four criteria of importance forshort sea shipping fuels and describes the investigatedfuels. The method, life cycle assessment (LCA), used toevaluate the environmental performance of the selectedfuels is also described.

Criteria for short sea shipping fuels

Short sea shipping is one part of the transport system,transporting cargo from short distances of regional

centres providing a port-to-port service. It is not astrictly defined segment, and many definitions exist inthe literature, see, for example, Medda and Trujillo3 andPaixao and Marlow.10 For the purpose of this study,short sea shipping is considered to be the regional distri-bution of cargo by sea. A number of characteristics thatare typical for sort sea shipping are summarised in Table1. The following four criteria are identified based on thedemands and opportunities presented in Table 1: (1)local and regional environmental impacts, (2) overallenvironmental impact, (3) infrastructure and (4) fuel costand competition with other transport modes. These cri-teria are not solely applicable for short sea shipping, butthey have been selected as they are identified as impor-tant when choosing a short sea shipping fuel.

The impacts on the local and regional environmentsare of more concern for short sea shipping comparedto deep sea shipping due to their operation pattern.Most of the short sea shipping transportation occursclose to coasts and populated areas. The emitted pollu-tants have, as a result, impact on the near environmentand human health for a larger part of the trip thanwhat is the case for deep sea shipping. Environmentalimpact categories that affect human health and theregional environment should therefore weigh moreheavily relative to the case of deep sea shipping.However, deep sea shipping also has regional impact.One example is shipping in the Southern North Seaand the English Channel, which are dominated by deepsea vessels using the major ports in Europe. The num-ber of such ships is much larger than the short sea ves-sels, for example, ro-ro ferries, and consequently, theimpact of short sea shipping is lower, relatively speak-ing. Examples of regional environmental impact cate-gories are acidification potential and fuel spills.

Short sea shipping is characterised by being both acomplement and a competitor to road and rail freighttransportation.3 This can be exemplified by ro-ro ships

Table 1. Short sea shipping characteristics that affect the choice of fuel.

Specific characteristics of short sea shipping Demand or possibility regarding choice of fuel Connection to criteria

Short distances compared to deep sea shipping Can use regionally available fuels (3)¼)operates in limited regional area Local and regional environmental problems are of

more concern than global problems(1)

Operates near coasts and populated areas Emissions will impact human health and ecosystemson land

(1)

Complement or competitor to road and railfreight transportation

Need to keep its competitive advantages, bothregarding transportation cost and service level aswell as environmental performance

(2) and (4)

Each vessel transports larger quantities and usesmore fuel than road freight transportation

Even if only a limited number of vessels changefuels, the fuel volumes will still be considerable forthe fuel producers

(3) and (4)

Smaller ships than in deep sea shipping, that is,decreased economies of scale and increased fuelconsumption per tonne cargo transported

More pressure on fuel efficiency and emissions (2) and (4)

Is subject to political restrictions, for example,cabotage

Regional and national regulations can beimplemented

(1)–(4)

Bengtsson et al. 45



that compete with road transportation and by lift-on–lift-off (lo–lo) ships that compete on longer distances,especially with rail transportation.10 This puts furtherrequirements on the environmental performance ofshort sea shipping considering that trucks use road die-sel with a maximum of 10 ppm sulphur (Euro VI), andthe emission regulations for particulate matter (PM)and NOX are becoming very strict. Rail traffic usesroad diesel or electricity and has emission regulationsfor NOX and PM, although not as strict as for trucks.In order to analyse the environmental competitivenesscompared to competing transport modes, that is, roadand rail, it is also important to evaluate the overallenvironmental impact of the fuels, for example, theemission of climate gases. This has been done for manysuggested road fuels, but the assessments do not allowfor a complete comparison for shipping fuels.

Infrastructure is important for all fuel users but thereare some special characteristics for short sea shipping.The operation in a limited geographical area gives spe-cific conditions in fuel selection as well. It is possible forshort sea shipping vessels to use fuels sold in these areaseven if they are not available everywhere in the world.One example of this is the infrastructure for LNG thathas been built up along the coast of Norway. Even ifshort sea vessels are smaller than deep sea vessels, eachvessel still uses much larger fuel quantities than a truckor a car. This means that fewer operators need tochange fuels in the short sea shipping segment than inroad transportation to reach the same quantities.

Fuel cost is an obvious category, and this is impor-tant for all transport modes. If the fuels can be used asroad transport, there is competition with road not onlyabout the freight but also about the energy carrier. Itwould therefore be an advantage if it is a cheap fuel

not suitable as energy carrier for road transportation.Criteria (1) and (2) are assessed in detail, and LCA isused as a basis for comparing the performance of thefuels, and criteria (3) and (4) are discussed more in gen-eral terms in section ‘Results and discussion’.

Investigated fuels

There are a number of possible fuels and a number ofdifferent production routes. In the present study, sevendifferent fuels are selected for a more detailed analysis:four fuels of diesel quality and three gaseous fuels. Thefuels compared are HFO, MGO, biomass-to-liquid(BTL), rapeseed methyl ester (RME), LNG and lique-fied biogas (LBG) (see Figure 1).

HFO with a sulphur content of 1% is included inthe assessment as a reference fuel, representing the situ-ation today. The most straightforward fuel change is touse a diesel fuel, from crude oil refining, with sulphurcontent below 0.1% and combine it with exhaust abate-ment technologies in order to comply with NOX ECAregulations. A fossil diesel fuel with less than 0.1% sul-phur content used today in many vessels is MGO.Another possible fuel is LNG, discussed, for exampleby Banawan et al.,11 and at different industry seminarsand conferences. The use of LNG in marine engineswill fulfil the SECA regulation, and also for most avail-able engine types, it will fulfil the most stringent NOX

ECA regulation. A possible downside with the use ofLNG is the methane slip from the engine as methane isa strong greenhouse gas. There is an uncertainty aboutthe magnitude of the methane slip, and it has beenreported to vary from 0.06 to 3.2 g CH4/MJ LNGdependent on engine type and load.12

Figure 1. Overview of the fuels included in this study.F-T: Fischer–Tropsch.

46 Proc IMechE Part M: J Engineering for the Maritime Environment 228(1)



The main energy carrier in LNG is methane.Methane can also be produced from biomass, that is,biogas, either by anaerobic digestion or by gasificationfollowed by methanation. The gas can be liquefied inthe same way as LNG into LBG. The produced lique-fied gas is here denoted as LBGar, when it is producedfrom anaerobic digestion of agricultural residues, anddenoted as LBGfr, when it is produced from gasifica-tion of forest residues. The reason to include two differ-ent production routes for biogas is that different rawmaterials are used. Including the gasification route thusmakes it possible to assess the use of woody biomass asraw material.

Two biofuels of diesel quality are also included:RME and BTL. RME is a fatty acid methyl ester fuelproduced from rapeseed oil and is one of the feedstockswhere fuel producers must compete with the foodindustry. BTL is produced by gasification of biomass,here wood, followed by the Fischer–Tropsch synthesis.The result is a pure diesel fuel with very low sulphurcontent.

Environmental assessment

LCA is used in order to compare the environmentalperformance of the fuels. LCA is a standardised toolthat addresses the potential environmental impact of aproduct or service in a cradle-to-grave perspective.13

The cradle represents raw material acquisition, which is

followed by production, transportation, use, wastemanagement and final disposal, the grave. Two ISOstandards (ISO 14040 and ISO 14044) give generalrequirements for how to conduct an LCA that needs tobe adapted from case to case. The guidelines byBauman and Tillman,14 Guinee15 and Heijungs andSuh16 have been used as support in this study. Table 2shows an overview of the methodological choicesimportant to make in an LCA. Some of them areexplained in more detail in the following sections. Thedata used in this study are based on two previous stud-ies.8,9 More details are found in the SupplementaryMaterial.

The functional unit is the unit for comparison in anLCA. It is here 1 tonne of cargo transported 1 km witha ro-ro vessel. The cargo capacity is adopted to takeinto account different storage requirements of the dif-ferent fuels (diesel fuels and methane-based fuels).Storage of methane-based fuels is more space consum-ing compared to diesel fuels since they have lower heatcontent per unit volume and require storage tanks of acertain design, generally about four times more space isrequired.31 This may reduce the cargo capacity to a cer-tain extent depending on type of vessel, type of fueltank and whether a suitable location of the LNG tankscan be found on-board. The vessel efficiency, that is,how much work (kWh) is needed to transport 1 tonnefor 1 km, is assumed to be 0.057 and 0.059 kWh for thediesel fuels and methane-based fuels, respectively. More

Table 2. Overview of the methodological choices.

Functional unit One tonne cargo transported one kilometre with a ro-ro vesselTime horizon 2010–2020Geographical boundaries SECAs in Northern Europe (the English Channel, the North Sea and the Baltic Sea)System boundaries Study includes all activities from raw material extraction to the release of waste to the environment, for

example, from cradle to propeller. Production of lubrication oil is not included in the system nor iswaste treatment of oil sludge and used lubrication oil. Manufacturing of capital goods is not included inthis study, for example, the manufacturing of the vessel

Investigated fuels Heavy fuel oil (HFO), marine gas oil (MGO), liquefied natural gas (LNG), liquefied biogas fromagricultural residues (LBGar), liquefied biogas from forest residues (LBGfr), rapeseed methyl ester (RME)and biomass-to-liquid (BTL)

Data sources Mainly secondary data for technologies available today. The data for the HFO and MGO from rawmaterial extraction to fuel production are from the core database European Reference Life CycleDatabase (ELCD).17,18 The data for LNG production are mainly from the JEC Well-to-Wheel study.19,20

The data for production of LBGar,21–23 LBGfr,

23,24 RME25 and BTL26 are from reports and articles. Thedata for the exhaust emissions from the ship are mainly from Cooper and Gustafsson27 and the SwedishNetwork for Transport and Environment (NTM)28 for the diesel fuels, but the exhaust emissions fromRME and BTL are modified based on the test on smaller marine engines.29 The emission factors for themethane fuels are based on the data from Wartsila for dual fuel engines.9,30 A more detailed descriptionis included in the Supplementary Material

Allocation Based on the lower heating value of the products with one exception. The impacts of HFO and MGOproduction have been allocated after each sub-process in the refinery based on lower heating value ofthe streams.17,18 Lower heating value has also been used to allocate environmental impacts to co-products in RME production.25 For the synthetic biodiesel production, energy has been used to allocateimpact between synthetic biodiesel and the co-production of heat and electricity26

Impact categories Primary energy use, global warming potential, acidification potential, eutrophication potential, humantoxicity, photochemical ozone formation and human health damage by particles and ozone

Limitations Exhaust abatement technologies are not evaluated. The impact of scrubbers and SCRs was discussed in aprevious study8

SECA: Sulphur Emission Control Area; SCR: selective catalytic reduction; JEC: Joint Research Centre of the EU Commission, ECUAR and

CONCAWE.

Bengtsson et al. 47



characteristics of the ro-ro vessel are included in theSupplementary Material.

Data on energy conversion and emissions are col-lected for all processes in the life cycle of the fuels.These flows contribute to different environmental prob-lems and are therefore sorted and assigned to variousimpact categories (Figure 2). In order to relate theimpact to a certain impact category, characterisationfactors or equivalence factors are used to get a commonunit. The factors are based on a common denominator,that is, release of H+ in the case of acidification. Thecharacterisation factors for the impact categories arepresented in the Supplementary Material.

Global environmental impact. Primary energy use and glo-bal warming potential (GWP) have global impact. Theprimary energy use for each fuel is calculated from thelower heating value of the raw materials and fuels usedin the life cycle. Primary energy use is included as ameasure for energy efficiency of the fuel chain.Greenhouse gases have different GWPs due to their dif-ferent radiative properties and lifetimes in the atmo-sphere. The GWP of 1 kg of a substance is defined asthe ratio between the increased infrared absorption itcauses and the infrared absorption caused by 1 kg ofCO2, defined for a certain time horizon. The most usedtime horizon in LCA is 100 years. Three different timehorizons are used in this study: 20, 100 and 500 years.32

Local and regional environmental impacts. Acidification andeutrophication are regional environmental impacts.The major acidifying pollutants are SO2 and NOX, andthe acidification potential is defined as the number ofhydrogen ions produced per kilogram substance

relative to SO2. This simplified model does not takeinto account the effect of environmental fate, back-ground deposition and ecosystem sensitivity. Theactual acidifying potential depends on where the acidi-fying pollutants are deposited. Here, three differentacidification potentials are included: two for differentgeographical scopes and one for disregarding environ-mental fate considering only the number of H+ ionsproduced.33,34 Eutrophication potential is associatedwith high levels of nutrients that lead to increased bio-logical productivity, for example, algae bloom.Nitrogen and phosphorus are the most common limit-ing nutrients. Since nutrients that limit biological pro-ductivity vary geographically, the actual eutrophicationpotential for a certain emission also varies geographi-cally. Here, three different eutrophication potentialsare included: two for different geographical scopes andone for disregarding environmental fate.33,34

Examples of emissions to air that have an impact onhuman health are primary PM and NOX. Two differentcharacterisation methods that impact human health areincluded.34,35 The first method contains specific charac-terisation factors for health effects of PM in Europe.These are expressed as the change in disability adjustedlife years (DALYs) for inhabitants in Europe due toemissions of particles, ammonia, NOX and SO2.DALYs is the sum of years lost and years disabled andis measured with the unit of year lost per kilogramemissions.35 The second is the impact category humantoxicity that covers impact on human health from toxicsubstances in the environment, and the characterisationfactors are referred to as human toxicity potentials(HTPs).

Another regional environmental impact category isphotochemical ozone formation. Ozone is a reactive

Figure 2. Overview of the impact categories included in this study.NMVOC: non-methane volatile organic compound.

The dashed lines between environmental flows and impact categories imply that the environmental flows are not included for all characterisation

models in this study.




compound and may be injurious to human health,construction materials and ecosystems and may alsodamage crops. The formation of ozone and otherphoto-oxidants is complex and depends on a numberof factors, namely, concentration of NOX and non-methane volatile organic compounds (NMVOCs) aswell as the intensity of ultraviolet radiation. The effectof different air emissions depends on the backgroundconcentration of NOX as well as the location. There aredifferent characterisation factors available for thisimpact category, but most are adapted to emissionsthat occur over land. In this study, most of the emis-sions will occur at sea. For example, 65% or more (upto 99% for HFO) of the NOX emissions emitted in thefuel life cycle are from the marine engines. A part ofthis is emitted in ports but the majority is emitted atsea. Hauschild et al.36 have presented site-dependentcharacterisation factors for exposure of vegetation andhuman beings to photochemical ozone for emissions ofNOX and NMVOC, and reported characterisation fac-tors for the Atlantic Ocean, the Baltic Sea and theNorth Sea. Characterisation factors are expressed ascumulative exposure of vegetation above 40 ppb (m2

ppm h/g) and exposure of human beings above 60 ppb(person ppm h/g). The characterisation factors fromHauschild et al.36 for the Baltic Sea are used in thisstudy. As a complement to this, the category ‘humanhealth damage caused by ozone’ is also included, appli-cable for the geographical boundary of Europe.35 It isexpressed as DALYs for inhabitants in Europe due tochanges in emissions of NOX and NMVOCs, and char-acterisation factors for maximum daily 8-h averageozone concentration are included.

Results and discussion

In this section, the fuels selected are compared to thefour criteria emphasised for short sea shipping fuels.

Local and regional environmental impacts

The impact categories included that have a local andregional impact are acidification, eutrophication,human health damage of PM10/human toxicity andphotochemical ozone formation potential. Selectedresults for these are presented in Figure 3 together withhow the different pollutants contribute to the differ-ent impact categories. A clear trend can be seen: theliquid fuels (HFO, MGO, RME and BTL) have sig-nificantly higher contribution to these impact cate-gories than the gaseous fuels (LNG, LBGar andLBGfr). Detailed results from the LCA for the impactcategories contributing to local and regional environ-mental impacts are presented in the SupplementaryMaterial. The common dependence on emissions ofNOX makes these impact categories linked, and it canalso be seen that the single most important pollutantcontributing to local and regional environmentalimpacts is NOX. Most of the NOX emissions originate

from combustion in diesel engines, and it is only themethane-based fuels (LNG, LBGar and LBGfr) thatare assumed to fulfil the Tier III NOX emission regu-lation in this study.

The reason that NOX emissions have a higher grav-ity for the acidification potential than SO2 emissions isthat most of the fuels investigated have low (for marinefuels) sulphur content while the specific NOX emissionsare high. HFO has 1%, MGO has 0.1% and the otherfuels contain below 0.1% sulphur on mass basis. In thecase of 3.5% sulphur in the fuel (the maximum allowedcontent for marine fuels globally today), the picturewould be different, with a much higher contributionfrom SO2 to the acidifying potential.

The impact category for PM10 shows contributionfrom emissions of NOX, SO2 and NH3 (ammonia) inaddition to directly emitted particles. The reason is thatthere is formation of PM in the atmosphere as sulphateand nitrate particles. These contributions will be signifi-cant for fuels/engines with high emissions of NOX andhigh concentration of sulphur in the fuel. The resultshows that NOX emissions are the largest contributorto PM10 and thereby to the largest human healthimpact from PM10. The intake factors of PM10, usedfor the calculation of the characterisation factors inVan Zelm et al. (2008),35 are about five times higherfor primary PM10 than for NOX, while the effect anddamage factors were identical for all PM10 independentof origin. Furthermore, the NOX emissions in the lifecycle are more than 15 times higher than the emissionsof primary PM10 on the basis of mass for all fuels inthis study. This explains the dominance of NOX withregard to contribution to PM10. The results for theHTP showed a similar trend but with even higher con-tribution from NOX.

The potential vegetation exposure to photochemicalozone is also expressed in Figure 3. It shows that theNOX emissions are totally dominant for this category.Emissions of NO can have both positive and negativeimpacts on photochemical ozone formation. NO reactsrapidly with ozone and forms NO2, thereby reducingthe ozone concentration. However, if the NO is emittedat sea, most of the NO will likely already be oxidised toNO2 when reaching populated areas and thus contri-buting to increased ozone concentration. The contribu-tion from NMVOC to this impact category is shown tobe slightly higher for the characterisation method ofhuman health damage caused by ozone. One reason forthis could be that the characterisation factors are aver-aged for Europe and not adjusted for emissions at sea.

It is important to keep in mind that if the diesel-based fuels were combined with exhaust abatement forNOX, they could possibly show even lower life cycleimpact than the gaseous fuels. This has been shown byBengtsson et al.8 for a selective catalytic reduction unitoperated under optimal conditions, and there may alsobe other techniques to reach Tier 3 by 2016. This alsoimplies that it is effective on a regional basis to regulatethe emissions of NOX from the engine. It is also

Bengtsson et al. 49



important to note that the emission factors for the dualfuel engine are less well known than the emission fac-tors for marine diesel engines with HFO and MGO, asthe latter have been tested more extensively. The emis-sion factors for the gas engine are from engine manu-factures since not many LNG-propelled vessels are inoperation today, and only few emission measurementshave been published. Industrial gas engines have shownto have higher NOX emissions compared to the emis-sion factors used here.30 Technical development of theengines also may give lower emissions when the tech-nology is implemented. Further studies on emissionsfrom marine gas engines are thus important before finalconclusions are drawn.

None of the characterisation methods available arespecially adjusted to emissions from shipping. Thisadjustment may be especially important for the impact

category photochemical ozone formation as spatial dif-ferentiation has been shown to be important.36

However, only small differences in the contributionfrom NOX and NMVOC to the different characterisa-tion methods used are found here. For a more preciseresult, the location of all emissions contributing to thephotochemical ozone formation needs to be specified,and their fate in the troposphere needs to be modelled,which is beyond the scope of this article.

A potential hazard for local and regional environ-ments, not covered by the LCA, is the risk of fuel spills,which can be caused by, for example, accidents,groundings and operational discharges. The environ-mental consequences of spills depend on factors suchas spill volumes, the nature of the fuel spilled and thesensitivity of the receiving environment and the biotasthat are exposed. Biodiesel is, for example, found to be

Figure 3. Life cycle (a) acidification potential, (b) eutrophication potential, (c) human health damage of PM10 and (d) vegetationexposure to photochemical ozone.HFO: heavy fuel oil; MGO: marine gas oil; LNG: liquefied natural gas; LBGar: liquefied biogas from agricultural residues; LBGfr: liquefied biogas from

forest residues; RME: rapeseed methyl ester; BTL: biomass-to-liquid.




less acutely toxic to aquatic organisms and to degrademore quickly than fossil diesel.37,38 Unconfined spills ofLNG will spread and boil at a very high rate and there-fore not remain in the water column; this also appliesfor LBGar and LBGfr. On the other hand, there are risksof fire or explosion and release of greenhouse gases.

Overall environmental impact

The overall results from the LCA are presented inFigure 4. The dashed line represents the impact fromthe use of HFO. The bars indicate whether the impactfrom a particular fuel is lower (below the dashed line) orhigher (above the dashed line) than for HFO. The resultsfrom this study show that marine transportation with allthe alternative fuels investigated has lower environmen-tal impact compared to HFO for almost all investigatedimpact categories. However, there are some exceptions.First, the primary energy use is lower for HFO than forany of the other studied fuels. Second, RME has lowerimpact than HFO only for 11 of the 16 characterisationmodels (only six are shown in Figure 4).

The two impact categories that are categorised asglobal problems are here primary energy use and GWP.The short sea shipping fuels with the best overall envi-ronmental impact are here indicated to be LBGar andLBGfr followed by LNG. The reason that LBGar andLBGfr are better than LNG is the lower life cycle emis-sions of greenhouse gases. LBGar is here assumed to beproduced from agricultural residues and manure andLBGfr from forest residues. Other biomass resourcescould result in different environmental profiles. It isalso assumed that electricity with an average Swedish

mix is used in the production and that heat from bio-mass is co-produced; worse global warming resultswould have been the result if it had been assumed thatcoal or oil was used to produce heat and electricity.There is also a risk of leakage of methane in the biogasproduction. This has been assumed to be marginal inthis study but could possibly affect the environmentalperformance of LBGar and LBGfr. The bio-based fuelsof diesel quality also show lower GWP than the fossilfuels, but their overall performance is not indicated tobe as good, mainly because the emissions of NOX fromthe combustion in the marine diesel engines are higher.

In Figure 5, GWP100 is presented with the contribu-tion from the three greenhouse gases assessed here. Itcan be seen that LNG, LBGar and LBGfr have a highcontribution from methane to the GWP. The relativecontribution will increase with about three times forGWP20. The high contribution from methane duringthe life cycle is mainly caused by unburnt methane fromcombustion and by leakage during the life cycle. Themethane slip from the dual fuel engine is here assumedto be 0.5 g CH4/MJ LNG. RME has a significant con-tribution from nitrous oxide to the GWP100, originatingmainly from the cultivation of rapeseed.

Infrastructure

The limited geographical operation of short sea ship-ping vessels makes it possible to use fuels available inone or a few ports where they operate. Another possi-ble benefit is the rather large fuel volume per vesselcompared to trucks. If there are locally produced fuelsavailable in a certain region, this could be a further

Figure 4. Summary of all investigated impact categories for all fuels compared to the environmental impact with HFO as marinefuel (represented by the dashed line).GWP: global warming potential; HFO: heavy fuel oil; MGO: marine gas oil; LNG: liquefied natural gas; LBGar: liquefied biogas from agricultural

residues; LBGfr: liquefied biogas from forest residues; RME: rapeseed methyl ester; BTL: biomass-to-liquid.

Bengtsson et al. 51



advantage as the fuel distribution cost will be lower.There are of course advantages with using the samefuels in short sea shipping as globally, even if short seashipping has greater possibility to find local andregional solutions. The cost of the vessel might behigher if similar vessels are not produced to the sameextent and the second-hand market for the vessel maybe more restricted.

Raw materials are not distributed evenly around theworld, and infrastructure for fuel distribution musttherefore be built. For the traditionally used fuels, thereis already existing infrastructure globally, and differenttypes of liquid fuels can utilise this. Fuels of diesel qual-ity can, for example, utilise the same infrastructure asMGO and HFO. One concern with biodiesel if it isused as shipping fuel is the risk of microorganisms andbiofilm formations on installations, especially if storagetimes are long.39,40

Natural gas infrastructure exists in many regions ofthe world in the form of pipelines and terminals andLNG carriers for large-scale distribution. LNG is usuallyproduced at remote natural gas locations as this is theway to make these resources available to the market.LNG infrastructure is growing and so are transportationvolumes.41 LNG could be very promising as a short seashipping fuel in regions close to LNG production, forexample, in Norway. One obstacle identified in the NorthEuropean LNG Infrastructure Project was the need forfloating small and medium LNG infrastructure in formof feeder vessels, bunker vessels and bunker barges.42

Today, there is only one existing bunker vessel for LNG,Pioneer Knudsen, but new vessels are planned. The othergaseous fuels, LBGar and LBGfr, can also use the infra-structure for LNG that is built up. Furthermore, there isinfrastructure for transportation of liquefied gas on land.

The infrastructure for the biogenic fuels is generally notfully developed as they are used mainly as pilot fuels or asroad transportation fuels in some regions. Depending onthe type of fuel, it may be possible to utilise the

infrastructure for fossil fuels. A possible transition towardsthe use of locally produced biofuels for a short sea ship-ping operating ro-pax ferry and the resulting environmen-tal impact are presented in an earlier study.9

Fuel cost and competition with other transportmodes

If short sea shipping uses the same fuels as road freighttransportation and the same exhaust abatement equip-ment, the environmental performance can be expectedto be better for short sea shipping than for road trans-portation due to the better fuel efficiency. However,this would require that the ships install the sophisti-cated emission control and abatement systems thatmodern road trucks have, and furthermore, it remainsto be shown that the particle filters used in trucks canbe scaled up to be used with marine engines. But usingthe same fuel also means the same fuel cost if there areno mode specific taxes or subsidies. Most of the alter-native fuels investigated here are also discussed for roadtransportation. The possibility of finding a cheaper fuelof lower quality that could be used for marine transpor-tation is a question not only for short sea shipping, butalso for the shipping industry as a whole. Table 3 givesan indication of what prices that can be expected forthe different fuels. LNG is the only fuel that is expectedto be sold at similar price as HFO and MGO in thenear future. BTL is not commercially available todayand therefore not included in the comparison. Thefuture fuel production cost is estimated to be in therange between 14 and 27 e/GJ.44

Conclusion

The following four criteria are identified as importantin order to select fuel for short sea shipping: (1) localand regional environmental impacts, (2) overall

Figure 5. Life cycle global warming potential divided on the contributing emissions.HFO: heavy fuel oil; MGO: marine gas oil; LNG: liquefied natural gas; LBGar: liquefied biogas from agricultural residues; LBGfr: liquefied biogas from

forest residues; RME: rapeseed methyl ester; BTL: biomass-to-liquid.




environmental impact, (3) infrastructure and (4) fuelcost and competition with other transport modes. Thefocus of this article is to assess the first two criteria.

The impact categories included that have a local andregional impact and thus are of specific interest forshort sea shipping are acidification, eutrophication,human health damage of PM10/human toxicity andphotochemical ozone formation potential. If only thesecategories are considered, the fuel with the lowestimpact is LNG, followed by LBG produced by anaero-bic digestion and from gasification of forest residues.The lower impact for these impact categories and fuels isdue to the lower NOX emissions from the dual fuelengine. However, if all impact categories investigated inthis article are included, LBG, from either anaerobicdigestion or gasification of forest residues, is insteadshown to be the fuel with the overall lowest impact. Forthese fuels, also the GWP is decreased compared withHFO. The methane-based fuels LNG, LBGar and LBGfr

have lower acidification potential, eutrophication poten-tial and human health impact than the fuels of dieselquality. This is primarily caused by lower emissions ofNOX during combustion in the dual fuel engines.

Emissions of NOX are shown to be a strong indica-tor for local and regional environmental impacts as itcontributes to 70% or more of the total impact for allinvestigated impact categories and characterisationmodels investigated here. NOX is thus a key pollutantto make short sea shipping more environmentally sus-tainable, especially when the sulphur content in marinefuels has been reduced to below 0.1%. This furtherimplies that if a full LCA of the fuel choice is not possi-ble, at least the NOX emissions from the engines shouldbe assessed. Furthermore, this stresses the importance toregulate emissions of NOX in order to reduce regionalenvironmental impact. The ECA regulations withdemands only on ships constructed after 2015 will give avery slow decrease of NOX emissions from shipping.

This article also emphasises that more environmen-tal impact categories are of importance for short seashipping compared to deep sea shipping. Reducing theimpact on climate change is important for all shippingsegments, but for short sea shipping, the focus mustalso be on reducing the local and regional

environmental impacts such as human health, acidifica-tion and eutrophication, making the decision of whatfuels to use more complex.

Funding

This study was funded by Vinnova.

Acknowledgements

This study was performed within the multidisciplinarymaritime competence and research centre Lighthouse atChalmers University of Technology. This study is alsopart of the research and development project Effship.An early version of this article was presented at theShort Sea Shipping Conference 2012 in Lisbon. Theauthors are grateful to the anonymous reviewers fortheir constructive comments.

References

1. Mulligan R and Lombardo G. Short sea shipping.

WMU J Marit Aff 2006; 5: 181–194.2. De Oses X and Castells M. The external cost of speed at

sea: an analysis based on selected short sea shipping

routes. WMU J Marit Aff 2009; 8: 27–45.3. Medda F and Trujillo L. Short-sea shipping: an analysis

of its determinants. Marit Pol Manag 2010; 37: 285–303.4. Hjelle HM. Short sea shipping’s green label at risk.

Transport Rev 2010; 30: 617–640.5. Environmental Health - Emerging Issues and Practice,

Jacques Oosthuizen (Ed.), ISBN: 978-953-307-854-0,

InTech, Available from: http://www.intechopen.com/

articles/show/title/the-comparative-environmental-perfor-

mance-of-short-sea-shipping.6. Winebrake JJ, Corbett JJ and Meyer PE. Energy use and

emissions from marine vessels: a total fuel life cycle

approach. J Air Waste Manag Assoc 2007; 57: 102–110.7. Corbett JJ and Winebrake JJ. Emissions tradeoffs among

alternative marine fuels: total fuel cycle analysis of resi-

dual oil, marine gas oil, and marine diesel oil. J Air

Waste Manag Assoc 2008; 58: 538–542.8. Bengtsson S, Andersson K and Fridell E. A comparative

life cycle assessment of marine fuels; liquefied natural gas

and three other fossil fuels. Proc IMechE, Part M: J Engi-

neering for the Maritime Environment 2011; 225: 97–110.9. Bengtsson S, Fridell E and Andersson K. Environmental

assessment of two pathways towards the use of biofuels

in shipping. Energ Policy 2012; 44: 451–463.10. Paixao AC and Marlow PB. Strengths and weaknesses of

short sea shipping. Mar Policy 2002; 26: 167–178.11. Banawan AA, El Gohary MM and Sadek IS. Environ-

mental and economical benefits of changing from marine

diesel oil to natural-gas fuel for short-voyage high-power

passenger ships. Proc IMechE, Part M: J Engineering for

the Maritime Environment 2010; 224: 103–113.12. Bengtsson S. Life cycle assessment of present and future marine

fuels. Goteborg: Chalmers University of Technology, 2011.13. ISO 14040:2006. Environmental management – life cycle

assessment – principles and framework.14. Baumann H and Tillman A-M. The hitchhiker’s guide to

LCA: an orientation in life cycle assessment methodology

and application. Lund: Studentlitteratur, 2004.

Table 3. Historical and expected price ranges for the assessedfuels.

Fuels Price range (e/GJ)

HFO 8–1243

MGO 12–1943

RME 25–3843

BTL –LNG 7–1242

LBGar and LBGfr 11–5043

HFO: heavy fuel oil; MGO: marine gas oil; LNG: liquefied natural gas;

LBGar: liquefied biogas from agricultural residues; LBGfr: liquefied biogas

from forest residues; RME: rapeseed methyl ester; BTL: biomass-to-

liquid.

Bengtsson et al. 53


http://www.intechopen.com/articles/show/title/the-comparative-environmental-performance-of-short-sea-shipping


15. Guinee JB. Handbook on life cycle assessment: operational

guide to the ISO standards. Boston, MA: Kluwer Aca-demic Publishers, 2002.

16. Heijungs R and Suh S. The computational structure of life

cycle assessment. Dordrecht: Kluwer Academic Publish-ers, 2002.

17. ELCD core database version II. Process data set: heavy

fuel oil; from crude oil; consumption mix, at refinery. 12March 2010. European Commission – Joint ResearchCentre – LCA Tools, Services and Data, Brussels,Belgium.

18. ELCD core database version II. Process data set: light

fuel oil; from crude oil; consumption mix, at refinery; 2000

ppm sulphur. 12 March 2010. European Commission –Joint Research Centre – LCA Tools, Services and Data.

19. Joint Research Centre of the EU Commission, ECUARand CONCAWE (JEC). Well-to-Wheels analysis of future

automotive fuels and powertrains in the European context.Well-to-Tank Report Version 3.0 – Appendix 2, JECWell-to-Wheels study, October 2008. Luxembourg: Publi-cations Office of the European Union for the JEC, Brus-sels, Belgium.

20. Joint Research Centre of the EU Commission, ECUARand CONCAWE (JEC). Input Data NG 181108.xls. JECWell-to-Wheels study Version 3.0, November 2008. Lux-embourg: Publications Office of the European Union forthe JEC.

21. Borjesson P and Berglund M. Environmental systemsanalysis of biogas systems – Part I: fuel-cycle emissions.Biomass Bioenerg 2006; 30: 469–485.

22. Borjesson P and Berglund M. Environmental systemsanalysis of biogas systems – Part II: the environmentalimpact of replacing various reference systems. Biomass

Bioenerg 2007; 31: 326–344.23. Johansson N. Production of liquid biogas, LBG, with cryo-

genic and conventional upgrading technology – description

of systems and evaluations of energy balances. Lund: Insti-tutionen for Teknik och Samhalle, Miljo- och Energisys-tem, Lunds Tekniska Hogskola, 2008.

24. Karlsson S and Malm D. Fornybar Naturgas – Forgasn-

ing av biobranslen for framstallning av metan eller vatgas.Svenskt Gastekniskt Center, 2005.

25. Bernesson S. Life cycle assessment of rapeseed oil, rape

methyl ester and ethanol as fuels: a comparison between

large- and smallscale production. Uppsala: Swedish Uni-versity of Agricultural Sciences, Department of Biometryand Engineering, 2004.

26. Jungbluth N, Frischknecht R, Emmenegger MF, et al.Life cycle assessment of BTL-fuel production: inventory

analysis. RENEW – Renewable fuels for advanced power-

trains. ESU-Services Ltd, Uster, Switzerland, 2008.

27. Cooper D and Gustafsson T. Methodology for calculating

emissions from ships: 1 update of emission factors. Norr-koping: Swedish Methodology for Environmental data(SMED), 2004.

28. Natverket for transporter och miljon (NTM). Environ-mental data for international cargo and passenger sea

transport. Version 2008-10-18. Stockholm: NTM, 2008.29. Cerne O, Strandberg J, Fridell E, et al. Rena turen – Ute-

vardering av miljoanpassade branslen i fritidsbatar. Swed-ish Environmental Research Institute, Stockholm,Svenska Miljoinstitutet, 2008.

30. Bengtsson S, Andersson K and Fridell E. Life cycle

assessment of marine fuels: a comparative study of four

fossil fuels for marine propulsion. Gothenburg: Chalmers

University of Technology 2011.31. Gullberg M and Gahnstrom J. North European LNG

Infrastructure Project – a feasibility study for an LNG fill-

ing station infrastructure and test of recommendations.

Baseline Report, October 2011, The Danish Maritime

Authority, Copenhagen.32. Intergovernmental Panel on Climate Change, Climate

change 2007: the physical science basis. Contribution of

Working Group I to the fourth assessment report of the

Intergovernmental Panel on Climate Change, eds S. Solo-

mon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B.

Averyt, M. Tignor, and H. Miller, Cambridge University

Press, Cambridge. 2007, pp 996.33. Huijbregts MAJ, Schopp W, Verkuijlen E, et al. Spatially

explicit characterization of acidifying and eutrophying

air pollution in life-cycle assessment. J Ind Ecol 2000; 4:

75–92.34. CML. CML-IA characterisation factors. Institute of

Environmental Sciences CML, Leiden University, The

Netherlands, November 2010.35. Van Zelm R, Huijbregts MAJ, den Hollander HA, et al.

European characterization factors for human health dam-

age of PM10 and ozone in life cycle impact assessment.

Atmos Environ 2008; 42: 441–453.36. Hauschild MZ, Potting J, Hertel O, et al. Spatial differ-

entiation in the characterisation of photochemical ozone

formation: the EDIP2003 methodology. Int J Life Cycle

Ass 2006; 11: 72–80.37. DeMello JA, Carmichael CA, Peacock EE, et al. Biode-

gradation and environmental behavior of biodiesel mix-

tures in the sea: an initial study. Mar Pollut Bull 2007; 54:

894–904.38. Hollebone, B. P., Fieldhouse, B., Landriault, M., Doe,

K., & Jackman, P. (2008b). Aqueous Solubility, Dispersi-

bility and Toxicity of Biodiesels. International Oil Spill

Conference Proceedings, 2008(1), 929–936. doi: 10.7901/

2169-3358-2008-1-92939. Sørensen G, Pedersen DV, Nørgaard AK, et al. Micro-

bial growth studies in biodiesel blends. Bioresour Technol

2011; 102: 5259–5264.40. Washington State University, University of Idaho, The

Glosten Associates Inc. and Imperium Renewables Inc.

Washington State Ferry biodiesel research & demonstra-

tion project. Washington State Department of Transpor-

tation, 2009.41. Kumar S, Kwon H-T, Choi K-H, et al. Current status

and future projections of LNG demand and supplies: a

global prospective. Energ Policy 2011; 39: 4097–4104.42. Danish Maritime Authority. North European LNG Infra-

structure Project – a feasibility study for an LNG filling

station infrastructure and test of recommendations. Copen-

hagen: Danish Maritime Authority, 2012.

43. Florentinus A, Hamelinck C, van den Bos A, et al. Poten-

tial of biofuels for shipping. Utrecht: ECOFYS Nether-

lands B.V., 2012.44. Edwards R, Larive J-F, Mahieu V, et al. Well-to-Wheels

analysis of future automotive fuels and powertrains in the

European context. Well-to-Wheels Report Version 2c,

JEC Well-to-Wheels study, March 2007. Luxembourg:

Publications Office of the European Union for the Joint

Research Centre of the EU Commission, ECUAR and

CONCAWE (JEC).




A comparative assessment with focus on environmental impact

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