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STYRELSEN FÖR

VINTERSJÖFARTSFORSKNING

WINTER NAVIGATION RESEARCH BOARD

Research Report No 77 Harri Eronen and Kaj Riska

IMPACT OF THE PROPOSED ENERGY EFFICIENCY REGULATION ON BALTIC TANKERS AND BULKERS

Finnish Transport Safety Agency Swedish Maritime Administration Finnish Transport Agency Swedish Transport Agency Finland Sweden

Talvimerenkulun tutkimusraportit – Winter Navigation Research Reports ISSN 2342-4303 ISBN 978-952-311-026-7

FOREWORD In its report no 77, the Winter Navigation Research Board presents the outcome of the project on impact of the proposed energy efficiency regulation on Baltic tankers and bulkers. The focus of the study is on how the energy efficiency regulation based on the Energy Efficiency Design Index influences the ice class ships. The ships that must sail in ice need at least some minimum power to proceed, while a maximum limit for the propulsion power is set by the EEDI regulation. The conflict between ice performance requirements and energy efficiency requirements is clearly shown to exist. The situation is noteworthy for the Finnish merchant ship fleet and for the whole Finnish winter navigation system. The Winter Navigation Research Board warmly thanks Mr. Harri Eronen and Professor Kaj Riska for this report. Helsinki and Norrköping June 2014 Jorma Kämäräinen Peter Fyrby Finnish Transport Safety Agency Swedish Maritime Administration Tiina Tuurnala Stefan Eriksson Finnish Transport Agency Swedish Transport Agency

i

IMPACT OF THE PROPOSED ENERGY

EFFICIENCY REGULATION ON BALTIC

TANKERS AND BULKERS

Contract: Trafi & SMA / ILS 3.5.2011

11.5.2011 / Kaj Riska & Harri Eronen

P805

ii

CONTENTS _________________________________________________________________________

1. INTRODUCTION 1

2. METHODOLOGY 2

3. IMPACT OF EEDI TO FINNISH MERCHANT FLEET 6

4. MEETING THE FUTURE EEDI REFERENCE LINES WITH

ICE CLASSED TONNAGE 8

4.1 General Questions Concerning Application of EEDI to Ice Class Ships 8

4.2 Possibilities to Reduce Main Engine Power/EEDI of the Ice Class

Ships 9

4.3 Possibilities to Increase DWT in Ice Class Ships 12

4.4 Possibilities to Reduce EEI in Two Example Ships 12

4.5 Summary of Single Factor Influence 18

4.6 Possibilities to Achieve Required EEDI at Different Phases Including

Multi-Factor Influence 20

5. ENERGY CONSUMPTION OF ICE CLASS SHIPS 26

6. POWER REQUIRED BY ICE CLASS 29

6.1 Minimum Required Power by Ice Class and Maximum Allowed by

Attained EEDI 29

6.2 Analysis of Two Ice Breaking Ships 32

7. CONCLUSION 35

Reference 36

APPENDIX 37

Cover figures: MS Eira, ESL Shipping and MT Jurmo, Neste Shipping

1

1. INTRODUCTION

The regulation on the energy efficiency of ships that is discussed at the International Maritime

Organization (IMO) at present is going to be based on an Energy Efficiency Design Index, EEDI,

that can be calculated for each ship. The calculated EEDI (‘attained EEDI’) must be below certain

value called the reference line (RL). The energy efficiency regulation does not apply to all ships,

especially RORO, ROPAX and PAX ships are at present outside the scope of the planned

regulation. Also the ship size measured by deadweight, dwt, sets the applicability limit; smaller

ships are outside the scope of regulation.

The EEDI calculation contains correction factors for ships having a Finnish-Swedish ice class; these

factors should make these ice class ships comparable with open water ships. This report is

concerned especially with ice classed ships as most of the ships under the Finnish flag have an ice

class. The study contains four different topics:

The impact of energy efficiency regulation on the Finnish merchant fleet;

Energy efficiency in the winter navigation system;

Ways to improve the energy efficiency of ice class ships and

The possible conflict between the minimum propulsion power required by the ice class rules

and the maximum power allowed by the energy efficiency regulations.

Results about each of these topics is given in this report.

The energy efficiency regulation is still under development at IMO. Thus the report is based on

some interim data. Specifically, the following three documents are used in calculations and

assessments:

1. IMO Circular Letter No. 3128: Amendments to MARPOL Annex VI. [applicable ships,

definition of the phases in the required reference line]

2. IMO MEPC.1/Circ. 681: Interim Guidelines on the Method of Calculation of the Energy

Efficiency Design Index for New Ships. [definition of EEDI]

3. IMO MEPC 58/4/8: Methodology for Design CO2 Index Baselines and Recalculation thereof.

[old reference lines for different ship types]

4. IMO MEPC 62/6/4: Calculation of Parameters for Determination of EEDI Reference Values

[new reference lines calculated by the IMO Secretariat]

2

2. METHODOLOGY

The basic definition of EEDI is the amount of CO2 produced normalized by the work done (‘benefit

to society’). The calculation of the index takes into account the auxiliary engine power as well as

power reductions from ‘innovative energy efficient technology’. For the purposes here the

following simplified form of the EEDI equation is used:

vdwtf

PPfEEDI

i

AEMEj

)21019075.0(1144.3

where the power of auxiliary engines in kW is taken as

250025.0 MEAE PP ; PME > 10000 kW

MEAE PP 05.0 ; PME ≤ 10000 kW,

where PME is the power of main engines. The ship speed v should be calculated at 75 % of the

maximum main engine power – this corresponds well with the speeds usually mentioned for ships

as the sea margin is 15 % and propeller design power is about 90 % of MCR.

The factors fi and fj are correction factors for ice class; fj takes into account the power addition for

ice performance and fi the decrease of the dwt because of the added steel for ice strengthening and

also because the hull shape is designed for ice and thus the block coefficient is smaller than in open

water ships. These coefficients are calculated as

ME

bpp

jP

Laf

, max 1.0, min

fppLe

dwt

Lcf

dPP

i

, max h

ppLg , min 1.0

where the engine power is MCR and the constants a,...,d are different for each ship type and the

expressions with these constants represent the average value for power and deadweight for open

water ships. The constants e,...,h give the limit for each ice class (and ship type) for the factors fj

and fi for an average ship of certain type and ice class. The figure below illustrates the calculation of

these factors; the figure is for tankers in ice class IA. It should be noted that several ships are

outside the min-max range and for these ships the value of the factor is taken at the limit.

3

Tankers, ice class IA

LPP [m]

0 50 100 150 200 250

f i a

nd f

j

0,6

0,8

1,0

1,2

1,4fi

fj

Limits

Fig. 1. The factors fj an fi for tankers in ice class IA.

The attained EEDI value is to be compared with a reference line value (denoted here RL) and the

attained EEDI should be smaller than the reference line value i.e. EEDI < RL. The reference lines

are given in form BL = a·dwt-c where the constants a and c are given for each ship type. There does

not exist a final decision about reference lines, yet. There are suggestions for reference lines which

are based on analyzing the present merchant ship fleet – ships larger than 400 GT - built in the 10

years period from the beginning of 1995 to the end of 2004. These reference lines are used here,

calculated by Denmark (MEPC 58/4/8). Also the IMO Secretariat has calculated new reference

lines (MEPC 62/6/4) and these are used in most of the calculation carried out here.

Once the reference lines are decided, then plan at IMO is to make the energy efficiency requirement

more tight by timestepwise (these steps are called phases, phases from 0 to 3). First time step is two

years (starting 1 January, 2013) and the two following ones four years. The last phase extends

indefinitely from 1 January, 2025. Thus the requirement for the attained EEDI will be

Attained EEDI ≤ Required EEDI = (1-X/100) x reference line.

The suggested values for the reduction factor X for the ship types that concern us here are given in

Table 1. It should be noted that energy efficiency regulation will. at least at this time, apply only to

seven ship types (four of these are relevant for the Finnish merchant fleet, viz. tankers, bulkers,

general cargo ships and container ships). The EEDI application has also a lower end in ship size,

this is different for each ship type.

4

Table 1. Reduction factors for the required EEDI. For the smaller size category in each ship type

there is a range given, the reduction factor is obtained by linear interpolation.

Ship type Size

Phase 0

1.1.2013 -

31.12.2014

Phase 1

1.1.2015 –

31.12.2019

Phase 2

1.1.2020 –

31.12.2024

Phase 3

1.1.2025 –

Bulk carrier

20000 dwt

and above 0 10 20 30

10000 –

20000 dwt NA 0 - 10 0 - 20 0 - 30

Tanker

20000 dwt


4000 –

20000 dwt NA 0 - 10 0 - 20 0 – 30

Container

ship

15000 dwt


10000 –

15000 dwt NA 0 - 10 0 - 20 0 – 30

General

cargo ship

15000 dwt


3000 –

15000 dwt NA 0 - 10 0 - 15 0 – 30

The reference lines calculated by Denmark and given in MEPC 58/4/8 were recalculated by the

IMO secretariat and presented in MEPC 62/6/4. The main change was that at first ships delivered

between January 1, 1995 to December 31, 2004 were included and in the latter calculation ships

delivered between January 1, 1999 to January 1, 2009 were included. Below a short study of the

influence of the change is made.

For bulk carriers, tankers and general cargo ships the reference lines are below the old ones for

smaller ships. The decrease is about 15 % for tankers at the limit of EEDI application (20 000 dwt)

at Phase0. There is a cross over point for bulkers and general cargo ships after which the new

reference lines are higher; these points are 99 800 dwt for bulkers and 48 100 dwt for general cargo

ships. For container ships the reference line calculated by the IMO secretariat is clearly above the

old one, but this is explained by the change that only 65% of the capacity is taken into account

when calculating the attained EEDI with the new reference line.

Open water bulkers

DWT

0 75x103 150x103 225x103 300x103

EE

DI [g C

O2/(

t x n

m)]

0

5

10

15

20

25Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

Open water bulkers

DWT

1x103 5x103 10x103 50x103 100x103

EE

DI

[g

CO

2/(

t x n

m)]

5

10

15

20

30

40

50Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

5

Open water tankers

DWT

0 75x103 150x103 225x103 300x103

EE

DI [g C

O2/(

t x n

m)]

0

5

10

15

20

25Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

Open water tankers

DWT

1x103 10x103 100x103

EE

DI

[g

CO

2/(

t x n

m)]

5

10

15

20

30

405060

Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

Open water general cargo carriers

DWT

0 10000 20000 30000 40000 50000

EE

DI

[g

CO

2/(

t x n

m)]

0

10

20

30

40Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

Open water general cargo carriers

DWT

1000 2000 50005000 10000 20000 40000

EE

DI [g C

O2/(

t x n

m)]

5

10

15

20

25

303540 Removed points

Included points

MEPC 58/4/8

MEPC 62/6/4

Open water container carriers

DWT

25x103 50x103 75x103 100x103 125x103 150x103

EE

DI [g C

O2/(

t x n

m)]

10

20

30

40

50

60Removed points

Included points

MEPC 58/4/8*

MEPC 62/6/4

Open water container carriers

DWT

5x103 10x103 20x103 50x103 100x103

EE

DI [g C

O2/(

t x n

m)]

10

15

20

25

30

3540

50

Removed points

Included points

MEPC 58/4/8*

MEPC 62/6/4

Fig. 2. The reference lines suggested by Denmark (MEPC 58/4/8) and those suggested by the IMO

secretariat (MEPC 62/6/4) plotted for four ship types and both on linear scale and logarithmic scale.

In the plot for the reference lines for container ships, the old reference line was calculated using the

full dwt and the new one using 65 % of the dwt, as the new practice is. This is taken into account.

6

3. IMPACT OF EEDI TO FINNISH MERCHANT FLEET

The Finnish merchant ship fleet, according to the data base received from TRAFI, consists of 1159

ships and barges. The total gross tonnage is 1 598 874 GT. Here, however, only ships larger than

400 GT are considered. The number of these ships (or barges) is 189 with a total gross tonnage of

1 512 152 GT. The ship type of these ships is given in Table 2. In this table is also given the number

of ships that fall under the energy efficiency legislation in each ship category. The number of ice

class ships in the Finnish merchant fleet are given in Table 3.

Table 2. The Finnish merchant fleet, ships larger than 400 GT.

ship

type

tank bulk cont tug IB PAX RORO,

ROPAX

General

cargo

barge other

N 11 6 3 6 9 5 52 32 41 24

GT 363171 50577 28550 5663 60517 19656 800488 76796 93955 12779

EEDI 11 4 3 - - - - 11 - -

Table 3. The number of ships in different ice classes of all ships larger than 400 GT and of those

falling under the energy efficiency regulation.

IA Super IA IB IC II others Ntot

> 400 GT 55 30 7 1 11 85 189

EEDI 16 13 0 0 0 0 29

The ratio )100/1( XBL

EEDI

determines if the ship fall outside the allowable limits for the energy

efficiency or not. This ratio for all four phases and for all ships under the energy efficiency

regulation is shown in Fig. 3. In the first phase (Phase 0) all ships fall under the required value but

as the limit is reduced from Phase 1 on, more and more ships are above the allowable limit; these

numbers are shown in Table 4. In all ship segments the energy efficiency regulation is going to have

a large impact already at the second i.e. Phase 1.

Table 4. The effect of energy efficiency regulation for Finnish ships using the old and new

reference lines.

Ships in

total

attained EEDI > RL·(1-X/100),

MEPC 58/4/8

attained EEDI > RL·(1-X/100),

MEPC 62/6/4

tanker GCS bulker cont tanker bulker cont GCS

Phase 0 9 0 0 0 0 3 0 0 0

Phase 1 29 5 5 4 1 6 4 1 10

Phase 2 29 5 5 4 2 11 4 2 10

Phase 3 29 11 6 4 2 11 4 3 11

7

DWT

0 25x103 50x103 75x103 100x103 125x103

EE

DI / R

efe

rence lin

e

0,6

0,8

1,0

1,2

1,4

1,6

1,8Phase 0

Phase 1

Phase 2

Phase 3

Fig. 3a. The attained EEDI divided be the required EEDI for ships in the Finnish merchant fleet

using the reference line MEPC 58/4/8.

DWT

0 25x103 50x103 75x103 100x103 125x103

EE

DI /

Refe

rence lin

e

0,8

1,0

1,2

1,4

1,6

1,8

2,0Phase 0

Phase 1

Phase 2

Phase 3

Fig. 3b. The attained EEDI divided be the required EEDI for ships in the Finnish merchant fleet

using the reference line MEPC 62/6/4.

8

4. MEETING THE FUTURE EEDI REFERENCE LINES WITH ICE

CLASSED TONNAGE

4.1 General Questions Concerning Application of EEDI to Ice Class Ships

4.1.1 EEDI application to existing ships

Is EEDI applied only for new ships? If so, existing high main engine power ice going ships would

certainly be used for longer than otherwise economically feasible? (Even more so than high

powered open water ships).

4.1.2 Finnish-Swedish ice class rules and DWT definitions

The present Finnish-Swedish ice class rules allow different (lower) draught mark in ice. This leads

to two different DWT-values for the same ship. How is this reflected in EEDI calculations?

4.1.3 Bow form considerations, EEDI and actual energy efficiency

Main engine power is in ice class ships often coming from minimum required power of the ice class

rules (or practical requirements for operations in ice). If future EEDI requirements restrict main

engine power under ice class rule requirements this may lead to designs with better icebreaking bow

forms i.e. lower resistance / lower power requirement in ice. (The reason for this is that e.g. Finnish-

Swedish ice class rules take in the account of bow form when calculating required power/thrust of

the propulsion machinery.)

With better icebreaking bow forms open water resistance gets, however, usually higher. On the

other hand even ice going ships will normally operate most of the time in open water and travel

only limited time in ice. Thus as a result this may lead to higher total emissions even if main engine

power and EEDI gets lower.

4.1.4 Ships with main engine power above ice class rule requirements

At present most of the ice class ships have main engine power somewhat above the minimum

required by the ice class rules. This is natural because the main engine powers rise by steps. It is

also beneficial to take an engine version with maximum output giving better performance in ice. In

many cases the ship owners have also added the power considerably above the minimum given in

the ice class rules in order to attain more independent operation capability limiting need of

icebreaker assistance.

One problem of the EEDI formula is also that the auxiliary engine power is normally taken as

percentage of the main engine.

EEDI ME power restrictions may lead to two kinds of problems:

EEDI upper limit would make it difficult to build ships which can operate independently in

the Baltic and of course in the Arctic where even higher power reserve is needed for the

ships operating without icebreaker assistance. Thus more icebreakers and icebreaker

assistance would be needed or whole transport chains e.g. from Northern Baltic could be

influenced. (Higher total emissions?)

9

If EEDI limits are getting lower the ice class ship powers would get closer to the minimum

allowed and thus the need of icebreaker assistance would rise. (Higher total emissions?).

Of course, especially in the Baltic, where ship size is quite small (EEDI not applied) and on the

other hand special ships like RO-RO ships (which have high power due to high open water speeds),

the above mentioned influence is somewhat limited.

4.1.5 Draught or otherwise limited ships

In many ice covered sea areas the water depth is limited (Baltic Sea, Arctic offshore terminal areas

and routes, Arctic rivers etc.). This means, that if economy of scale is utilized by adding ship DWT

by building high beam ships, the power in ice will rise above the level of the ships with normal

main dimensions. The reason for this is that the ice resistance is rising about directly proportional to

ship beam.

4.1.6 Other issues

In ice going ships redundant propulsions systems are sometimes used. Influence of these on EEDI is

negative although actual emissions do not rise.

4.2 Possibilities to Reduce Main Engine Power/EEDI of the Ice Class Ships

Once the attained EEDI of a ship is above the reference line, some means to reduce the attained

EEDI must be considered. The attained EEDI can be reduced by introducing some energy saving

methods like waste heat recovery or use of wind and solar energy – these are, however, general

means and can be applied in any ship – thus these are not considered here. The best alternative is if

the attained EEDI can be reduced by making some changes in the ship design. These methods

include the following:

Method

(related to reducing the resistance) Description

Bow shape optimization An ice breaking bow reduces much the power needed.

Main dimensions

The ship beam influences much the ice resistance,

reducing the beam while keeping the dwt constant,

reduces the power needed.

Method

(related to enhancing propulsion) Description

Propeller optimization

Larger propeller diameter increases the propulsive

efficiency (especially when moving from single to twin

screw solution).

Special propulsion Nozzles and CRP’s increase the delivered thrust. CPP is

more efficient in ice thus reducing the required power.

Method

(related to machinery efficiency) Description

Diesel-electric machinery Better efficiency in ice thus reducing the required power.

Use of shaft generators If shaft generators are used, the power of these is deduced

from the main engine power. Required ice power is,

10

however, the maximum power available at the propeller.

Method

(other) Description

Use of two powers

The ship could have a high power in ice which is exempt

from attained EEDI calculation and the power required in

open water could thus be much lower. A dual mode ship

utilizes this principle.

Use of LNG Using gas as fuel reduces the CO2 emissions.

Most of the above means are analyzed below.

4.2.1 Different summer and ice powers

Perhaps the best way to fulfill EEDI target to reduce emissions (without disturbing the winter

navigation or leading to hull forms which are uneconomical in open water) would be to limit the

ME power level in open water and allow higher power in ice. This could be done by having

different power settings of the engine i.e. limiting the open water speed. The modern common rail

engines can have different ice and open water programs. The use of summer settings could be

controlled e.g. by checking ice class ship voyage recording data.

4.2.2 Better bow shape

To reduce power needed in ice bow lines shaping to more icebreaking form reduces required main

engine power because e.g. Finnish-Swedish ice class rules take in account of the bow shape. The

total influence in emissions may however be contra dictionary, see 4.1.2.

4.2.3 Ship is built more narrow and longer

The required ice class power gets lower when ship breadth is reduced and ship length is added at

same time keeping DWT constant. The open water resistance is normally not much influenced in

this kind of modification. So the influence is positive as well on actual emissions as on EEDI.

However ship price gets a little higher and certain ship type limitations reduce this kind of

possibilities.

4.2.4 Propeller type influence and special propellers

Propeller in nozzle gives up to about 20-30 % higher thrust at low ice operation speeds reduces the

power need in ice at same ratio i.e. minimum ME power required by the rules. This is true if ice

floes do not disturb the nozzle circulation or lead to nozzle clocking. Problems may arise especially

in heavy ice conditions if draught / propeller clearance are small / ice thickness is high compared to

nozzle diameter.

Nozzle benefit is reducing when the speed gets higher. The breakeven point compared to open

propeller is normally about 12 knots and with special short nozzles about 15 knots. At higher speeds

nozzle propeller efficiency is worse than with open propeller reducing thus open water speed with

same power.

11

CP-propeller lowers the required ice power e.g. in Finnish-Swedish ice class rules compared to

fixed pitch propeller as the CPP gives higher thrust in varying ice conditions.

Innovative solutions like Azipod+conventional CP-propeller in line might also be used (Special

CRP solution).

4.2.5 Adding propeller diameter / using multi shaft arrangements

Adding propeller diameter reduces inversely proportionally the ice class power in Finnish-Swedish

ice class rules as higher thrust is given. Thus adding propeller diameter reduces power needed

distinctively more in ice than in open water. However propeller clearance, ice torque, distance to

waterline etc. should be considered carefully when increasing propeller diameter in ice class ships.

Ice class ships have often smaller propeller diameter than open water ships due to ice loading.

Changing to twin shaft (or multi shaft) arrangement from single shaft may be used to reduce

required ice power together with an increase of propeller diameter(s). However, multi shaft

arrangements may lead to higher power need in open water depending on the actual case and

certainly to higher price.

4.2.6 Diesel-electric machinery

The needed propulsion power in ice by using DE-machinery is lower than with diesel machinery.

The main reasons for this are better rpm-control and high provided torque of electric motor when

revolutions go down in ice. Thus the same thrust is maintained with the lower power than in the

case of conventional diesel machinery. Also the power station principle may cut considerably the

emissions especially when ship operation profile includes varying engine loadings like is the

situation often with ice going ships. The EEDI is, however, based on the ME-power, not the power

in shaft lines or actual emissions.

4.2.7 Dual mode ships

Dual mode ships that are aimed to go astern in ice and forward in open water may be beneficial in

some cases if lower power is accepted in ice class rules compared to conventional bow first

versions. The open water bow reduces at the same time actual emissions. As these ships require

azimuthing propulsion and also practically DE machinery, this is an expensive solution.

4.2.8 LNG-fuel in ice going ships

Using LNG as fuel in ice going ships has similar positive influence on emissions as in open water

ships. Gas engines and dual-fuel engines, however, tolerate badly swift load variations which are

typical in especially small ice going ships and in heavy ice conditions. This might lead to diesel use

at least in some cases. Dual fuel engine could use diesel fuel in heavy ice.

4.2.9 Other possibilities

One way to reduce EEDI is to install shaft generator. This means that installed power may be higher

with same EEDI and if then in ice the shaft generator is not used it would be easier to fulfill ice

performance requirements.

12

4.3 Possibilities to Increase DWT in Ice class Ships

4.3.1 Use of high tensile steel or special materials in ice strengthening

Normally use of high tensile steel in ice strengthening may influence a couple of percents on DWT

at maximum with corresponding small influence on calculated EEDI.

4.4 Possibilities to Reduce EEDI in Two Example Ships

4.4.1 Studied ships

The ships used in the comparison represent typical larger ice class IA Super ships in the Finnish

merchant ship fleet.

M/S EIRA

Ship type Bulk Carrier

DWT 19625 t

Main engine power 7860 kW Estimated rule min. value 7800 kW

Speed at 75% MCR 14 knots

Loa 157 m

Lbp 148 m

B 24.6 m

T 9.03/9.22 m

H 13 m

Propeller CPP dia 5 m

Ice class IA Super

Bow shape ”Ice bow” with a stem angle 40˚

EEDI calculated 11.94

EEDI phase 0 (8.62) not applicable because DWT is under 20 000 t

1 7.79 from 2015)

2 6.96 from 2020

3 6.13 from 2025

M/S JURMO

Ship type Chemical/Product Carrier

DWT 25049 t

Main engine power 9450 kW Estimated rule min. value 7940 kW, (+1500 kW shaft

gen.)

Speed at 75% MCR 15 knots

Loa 169.5 m

Lbp 159.12 m

B 23.75 m

13

T 10.9 m

H 14.9 m

Propeller CPP dia 5.8 m

Ice class IA Super

Bow shape Bulbous bow

EEDI calculated 7.88

EEDI phase 0 8.70

1 7.83 from 2015

2 6.96 from 2020

3 6.09 from 2025

4.4.2 Possibilities to reduce EEDI in example ships

4.4.2.1 Better bow shape

M/S EIRA

M/S EIRA has stem angle of 40˚ and here the influence of getting it down to 30˚ is estimated. The

power needed in ice according to 1AS rules gets down about 11.7%. It is also estimated that open

water resistance rises about 2.5% and ship length is added by 4 m due to lower rake of bow.

Thus ME power is reduced from 7860 kW to 6938 kW. The normal ME power of open water bulk

carriers of this size is about 5000 kW.

Due to lower ME power and extra resistance the open water service speed is reduced from 14 knots

to 13.44 knots. Comparing to similar size open water bulk carriers the speed is average, normal

values are between 13 and 14 knots.

As a result:

- EEDI of the ship is reduced from 11.94 to 10.14

- EEDI reduction 15.1% (1.80 units)

Considerable influence on EEDI reduction is that fi factor is rising from the original 1,0 to 1.085 when

the ship length has been estimated to rise by 4 m due to new bow form.

Estimated price influence:

- new longer bow + 0.3-0.6 MEUR

- ME power reduction - 1.5 MEUR

M/S JURMO

M/S JURMO has bulbous bow and here the influence of making a icebow with stem angle of 40˚ is

estimated. The power needed in ice according to IA Super rules goes down about 12.8 %. It is also

estimated that open water resistance rises about 10% and ship length is added by 9.5 m due to new

bow.

14



Due to lower ME power and extra resistance the open water service speed is reduced from 15 knots

to 14.2 knots. Comparing to similar size open water bulk carriers the speed is on high side, normal

values are between 13 and 14 knots.

As a result:

- EEDI of the ship is rising from 7.88 to 8.51

- EEDI rise 8.0% (0.63 units)

Considerable influence on EEDI rise is that fj factor is rising from the original 0.733 to 0.914 when

the ship length has been estimated to rise by 9.5 m due to new bow form.


- new longer bow + 0.7-1.4 MEUR


4.4.2.2 Ship is built more narrow and longer

M/S EIRA

M/S EIRA breadth is 24.6 m and here the influence of getting it down 1 m from 24.6 m to 23.6 m

(4.1%) is estimated. The power needed in ice according to IA Super rules gets down about 4.25 %.

the same time it is estimated that open water resistance does not change and ship length is added

by 9 m so that original hold capacity and DWT can be maintained.



Due to lower ME power the open water service speed is reduced from 14 knots to 13.83 knots.

Comparing to similar size open water bulk carriers the speed is average, normal values are between

13 and 14 knots.

As a result:


- EEDI reduction 19.2 % (2.29 units)

Considerable influence on EEDI reduction is that fi factor is rising from the original 1.0 to 1.20 when

the ship length has been estimated to rise by 9 m due narrow hull.


- new longer bow + 1-2 MEUR


15

M/S JURMO

M/S JURMO breadth is 23.75 m (already quite narrow) and here the influence of getting it down

0.5 m from 23.75 m to 23.25 m (2.1 %) is estimated. The power needed in ice according to 1AS

rules gets down about 3.6 %.

Same time it is estimated that open water resistance does not change and ship length is added

by 5.5 m so that original hold capacity and DWT can be maintained.




Comparing to similar size open water bulk carriers the speed is on high side, normal values are

between 13 and 14 knots.

As a result:



Lengthening of the ship has in this case only minor influence on EEDI (ice factors).


- new longer bow + 0.5-1 MEUR


4.4.2.3 Nozzle propeller

M/S EIRA

It is assumed that ice class power is reduced by 22% by using nozzle propeller. (IA Super channel

speed 5 knots, see however comments in 2.3 i.e. nozzle advantage may vanish in heavy ice

conditions).




Comparing to similar size open water bulk carriers the speed is normal, normal values are between

13 and 14 knots. I.e. utilizing the reduced power is not always possible.

As a result:




- Nozzle propeller extra cost +0.3 MEUR


16

M/S JURMO

It is assumed that ice class power is reduced by 22 % by using nozzle propeller. (IA Super channel

speed 5 knots, see however comments in 4.2.3 i.e. nozzle advantage may vanish in heavy ice

conditions).


carriers of this size is about 7000-8000 kW.


Comparing to similar size open water bulk carriers the speed is near average, normal values are

between 13 and 15.5 knots.

- EEDI of the ship is rising from 7.88 to 7.99

- EEDI rise 1.4 % (0.11 units)

Main reason for small influence on EEDI is that the factor fj is rising from 0.735 to 1.000 due to

ME power reduction.


- Nozzle propeller extra cost +0.3 MEUR

- ME power reduction - 3 MEUR

4.4.2.4 Use CRP-propeller

CRP-propeller influence can be compared to nozzle propeller / propeller diameter adding i.e. higher

efficiency / thrust helps in ice. The extra thrust varies from couple of percents to about 15%

depending on propeller diameters etc.

4.4.2.5 Adding propeller diameter

M/S EIRA

The 5 m propeller diameter of M/S EIRA is quite large so the possibility to add it is restricted. It is

assumed however that addition of dia. to 5.23 m would be possible (to get higher thrust / lower

required ice class power). Draft aft and propeller clearance should however be considered carefully.

Thus ME power according to ice class requirements is reduced from 7860 kW to 7514 kW (4.4%).

The influence to power needed in open water due to larger diameter propeller higher efficiency is

only about 1%. The normal ME power of open water bulk carriers of this size is about 5000 kW.


Comparing to similar size open water bulk carriers the speed is about average, normal values are

between 13 and 14 knots.

As a result:

17




- Higher dia propeller extra cost + 0.02 MEUR


M/S JURMO

The 5.8 m propeller diameter of M/S JURMO is quite large so the possibility to add it is restricted.

However comparing to other ships the addition of dia. to 6.2 m could be possible (to get higher

thrust / lower required ice class power). Draft aft and propeller clearance should however be

considered carefully and also propeller tip speed is getting too high. (Lower rpm needed).

Thus ME power according to ice class requirements is reduced from 9450 kW to 8840 kW ( 6.5%).

(The influence to power needed in open water due to larger diameter propeller higher efficiency is

only about 1.5 %.) The normal ME power of open water bulk carriers of this size is about 5000 kW.


Comparing to similar size open water bulk carriers the speed is in normal range, normal values are

between 13 and 15.5 knots.

As a result:


- EEDI reduction 1.4 % (0.11 units) (EEDI increases 1.0% if the power without PTO is used)


- Higher dia propeller extra cost + 0.03 MEUR

- ME power reduction - 1 MEUR

4.4.2.6 Use of LNG fuel

M/S EIRA

The use of LNG as fuel for main engines (e.g. dual fuel engines) reduces the CO2 emissions about

20% when the main engine power kept as original.

As a result:


- EEDI reduction 19 % (2.26 units)

The cost of LNG machinery is about 2 MEUR higher than conventional machinery.

18

M/S JURMO

The use of LNG as fuel for main engines (e.g. dual fuel engines) reduces the CO2 emissions about

20% when the main engine power kept as original.

As a result:


- EEDI reduction 18.5 % (1.46 units) (EEDI decreases 18.9% if the power without PTO is

used)

The cost of LNG machinery is couple of MEUR higher than conventional machinery.

4.5 Summary of Single Factor Influence

Summary of the influence on different single factors on calculated EEDI is presented in the

following tables.

M/S EIRA

Calculated EEDI of M/S EIRA is 11.94

In the table on the right column EEDI is presented also without ice class correction factors.

Required EEDI: (Reference line req. 8.62)

Phase 1 7.79

Phase 2 6.96

Phase 3 6.13

Method to EEDI EEDI ME power Open EEDI

reduce EEDI reduct’n reduction water w/o

speed ice fact.

Original 11.94 +-0% +-0% 14.0 kn 13.7

Better bow Stem angle reduced 10.14 15.1 % 11.7 % 13.44 kn 12.6

shape from 40˚ to 30˚

L incr. 4 m

Breadth B reduced 4.1 % 9.65 19.2 % 4.25 % 13.83 kn 13.2

reduced (1m), L incr. 9 m

Nozzle 10.78 9.7 % 22 % 13.12 kn 11.4

propeller

Adding Dia raised 4.6% 11.52 3.5 % 4.4 % 13.87 kn 13.2

propeller (5-5.23 m)

diameter

19

Use of 9.69 19 % - 14 kn 11.0

LNG fuel original

M/S JURMO

Calculated EEDI of M/S JURMO is 7.88


Required EEDI: Reference line req. 8.70

Phase 1 7.83

Phase 2 6.96

Phase 3 6.09


reduce EEDI reduct’n reduction water w/o

speed ice fact.

Original 7.88 +-0% +-0% 15.0 kn 12.0

Better bow Stem changed 8.51 8.0% 12.8 % 14.2 kn 11.1

shape from bulb to 40˚ rise

L incr. 9.5 m

Breadth B reduced 2.1 % 7.85 0.4% 3.6 % 14.86 kn 11.7

reduced (0.5m)

L incr. 5.5 m

Nozzle 7.99 1.4 % 22 % 14.13 kn 9.9

propeller rise

Adding Dia raised 6.8 % 7.77 1.4 % 6.5 % 14.75 kn 11.4

propeller (5.8-6.2 m)

diameter

Use of 6.42 18.5 % - 15 kn 9.7

LNG fuel original

M/S JURMO

Calculated EEDI of M/S JURMO is 7.88**

with actual ME power 9450 kW.

In this table the results are presented on the assumption that 1500 kW shaft generator power

is taken out so that the ship has minimum 1ASuper main engine power 7950 kW. I.e. MCR is

7950 kW and no shaft generator.

The influence on basic ship is that the EEDI value goes down from 7.88 to 7.58 i.e. 4.1 %.

20


Required EEDI: Reference line req. 8.70

Phase 1 7.83

Phase 2 6.96

Phase 3 6.09


reduce EEDI with reduct’n reduction water w/o

ice fact. speed ice fact.

NEW Original 7.58 +- 0% +-0% 15.0 kn 10.1

(7.88)**

original

Better bow Stem changed 7.79 2.8% 12.8 % 14.2 kn 9.3

shape from bulb to 40˚(8.51)**

rise

L incr. 9.5 m

Breadth B reduced 2.1 % 7.74 2.1% 3.6 % 14.86 kn 9.8

reduced (0.5m) (7.85)**

rise

L incr. 5.5 m

Nozzle 6.72 11.3% 30 % 13.75 kn 7.7

propeller (7.99)**

Adding Dia raised 6.8 % 7.65 1.0 % 6.5 % 14.75 kn 9.6

propeller (5.8-6.2 m) (7.77)** rise

diameter

Use of 6.15 18.9 % - 15 kn 7.1

LNG fuel (6.42)**

original

**

original values

4.6 Summary Possibilities to Achieve Required EEDI at Different Phases Including Multi-

Factor Influence

4.6.1 Summary of results

In the tables below a summary of possible methods to achieve EEDI at different phases is

presented. (Of course other combinations and e.g. even better icebreaking bow could be utilized).

It can be generally concluded that based on the two calculated ships it is not possible to draw

general conclusions of EEDI influence on ice going ships typically operating in the Baltic Sea. The

main reason for this is the partly contra dictionary behaviour of the ice factors at least on smaller

ships with special dimensions. Also the influence of different methods differs quite a lot from each

other in the example ships. Other important factors which should be studied are ship size, type,

proportions and ice class.

21

M/S EIRA

Calculated EEDI of M/S EIRA is 11.94

Required Calculated Methods to achieve required EEDI

EEDI EEDI

(Ph 0 8.62) 8.48 Breadth reduced+bow 30˚+nozzle

Ph1 7.79 6.86 Breadth reduced+bow 30˚+nozzle +LNG fuel

Ph 2 6.96 6.86 Breadth reduced+bow 30˚+nozzle +LNG fuel

Ph 3 6.13 Cannot be achieved with IA Super ME power

NOTE: The full influence of the extra thrust of about 22% at 5 knots when using nozzle

in open water has been fully utilized. At least in heavy channel however the nozzle

advantage is vanishing.

M/S JURMO

Calculated EEDI of M/S JURMO is 7.88

Required Calculated Methods to achieve required EEDI

EEDI EEDI

Ph 0 8.70 7.88 No changes required

Ph 1 7.83 7.81 Breadth reduced

Ph 2 6.96 6.42 LNG fuel

Ph 3 6.09 6.10 Breadth reduced+bow 30˚+nozzle +LNG fuel

4.6.2 Remarks on calculations made using different single/combined methods to achieve

required EEDI

In the tables below the different methods to reduce EEDI have been presented. In each case the ship

main engine power has been reduced from the original in the ratio coming from calculated power

according IA Super rules in each case.

Note also:

- EEDI reference line value is calculated according to MEPC 62/6/4 10 January 2011 Calculation of

Parameters for determination of EEDI Reference Values

- Ship open water speed has been reduced accordingly down when ME power is changed, and

also bow form influence on the resistance and the better efficiency of larger diameter propeller

22

has been taken into account

- The nozzle extra thrust has been fully utilized i.e. 22% reduction has been used in ice class power

- In the table EEDI red. % means the reduction percent of the method(s) used on EEDI compared

to the original EEDI of the ship

- In the table ice red % means the reduction % coming from ice factors fi ja fi on EEDI compared

to EEDI calculated without them

M/S EIRA

Method Calculated EEDI red. fj fi EEDI ice red. % Ship speed/

EEDI % w/o ice MCR power

factors

Original. 11.94 +-0% 0.865 1.0 13.65 12.5 % 14.0 kn/7860 kW

ship

B reduced 9.65 19 % 0.869 1.204 13.23 27 % 13.83kn/7525kW

B red.+LNG 7.83 34.5 % 0.869 1.204 10.71 27 % 13.83kn/7525kW

Bow 30˚ 10.14 15 % 0.868 1.085 12.6 19.5 % 13.44kn/6938kW

B red.+ 10.04 16 % 0.988 1.201 12.19 18 % 13.32kn/6675kW

bow 30˚

B red.+ 9.59 19.5 % 0.953 1.204 12.08 20.5 % 13.39kn/6650kW

nozzle

Bow 30˚+ 9.64 19.5 % 1.0 1.085 10.46 8 % 12.58kn/5411kW

nozzle

B red.+ 8.48 29 % 1.0 1.201 10.18 16.5 % 12.44kn/5206kW

bow 30˚+

nozzle

B red.+ 9.79 18 % 1.0 1.201 11.76 17 % 13.2 kn/6382 kW

bow 30˚+

larger prop.

B red.+ 6.86 42.5 % 1.0 1.201 8.23 16.5 % 12.44kn/5206kW

bow 30˚+

nozzle +

LNG fuel

NOTE:

23

Although reducing of the ship breadth lowers EEDI 19% and making better ice bow 15% (when

used separately) their combined use lowers EEDI only 16%. On the other hand if also nozzle is used

it is advantageous to use the combination of lower breadth and better ice bow compared to the

variation that nozzle is added to only one alternative. The reason for this is the influence of ice

factors, especially when length is added there is a sharp change in ice factors. See Appendices.

- 1 m breadth reduction and corresponding lengthening of the ship, which means also 4.5% power

reduction, lowers EEDI 19% although the emissions go down only about 3%/t nm.

- Making better ice bow and corresponding lengthening of the ship, which means also12 % power

reduction, lowers EEDI 15 % although the emissions go down only about 9%/ t nm.

M/S JURMO



factors

Original 7.884 +-0% 0.735 1.147 12.00 34 % 15.0 kn/9450 kW

ship

B reduced 7.81 0.4% 0.790 1.198 11.69 33 % 14.86kn/9113kW

Bow 40˚ 8.51 +8 % 0.914 1.195 11.06 23 % 14.2 kn/8240 kW

Nozzle 7.99 +1.4 % 0.917 1.147 9.94 19.5 % 14.13kn/7371kW

Larger prop. 7.77 1.4 % 0.765 1.147 11.42 32 % 14.75kn/8840kW

LNG fuel 6.42 18.5 % 0.735 1.147 9.7 34 % 15.0 kn/9450 kW

B red.+ 9.09 +15.3 % 1.0 1.190 10.82 16 % 14.02kn/7959kW

bow 40˚

B red.+ 7.54 4.5 % 1.0 1.190 8.97 16 % 13.18kn/6208kW

bow 40˚+

nozzle

B red.+ 8.59 +9 % 1.0 1.190 10.22 16 % 13.88kn/7445kW

bow 40˚+

larger prop.

B red.+ 6.10 22.6 % 1.0 1.190 7.25 16 % 13.18/6208 kW

bow 40˚+

nozzle+

LNG fuel

NOTE:

24

In the case of JURMO the use of single methods which actually reduce emissions keep however

EEDI value nearly constant or even rise it. I.e. it is not useful to use them. Exception is naturally

use of LNG fuel.

The combination of reduced breadth+ice bow leads to 15% higher EEDI when it actually reduces

emissions about 10% / t·nm. Same can also be said of the alternative Bred.+ice bow+larger

propeller EEDI rising 9%.

When nozzle is used with reduced breadth+ice bow, the advantage is limited, i.e. EEDI

lowers 4.5 % whereas emissions go down by about 17 %.

APPENDIX

Length varied while keeping the other parameters fixed. MT Jurmo is calculated with the ME power

without shaft generator.

Fig. 4a. Influence of the length variation on EEDI

Propulsion power varied while keeping the other parameters constant. MT Jurmo is calculated with

the ME power without shaft generator.

Eira

25

Fig. 4b. Influence of the main engine power on EEDI.

26

5. ENERGY CONSUMPTION OF ICE CLASS SHIPS

The attained EEDI describes the production of CO2 per transported ton; it is clear that the

underlying variable is the energy consumption per transported ton. The CO2 emissions can be

decreased by using better fuels or gas. Here, however, the winter navigation system is investigated

in view of the total energy consumption. Ships that come to Finland wintertime need often

icebreaker escort and thus the total CO2 emissions per transported ton should take into account the

icebreaker emissions and the energy used by icebreakers.

The study of the emissions in the winter navigation system is made by comparing four different ship

versions. The studied ship is a bulk carrier of 20000 dwt and beam 24.6 m. The reference line value

for this ship is 8.541 (old 9.761) nmdwt

gCO

2 . The ship versions studied are:

1. Ice going ship 10 MW

Ice class IA Super

Power 10000 kW

Bow angle φ1 25o

Length 152 m

vow 15 kn

fj 0.8669

fi 1.0650

EEDI 15.88

Ice class corrected EEDI 13.07

2. Ice going ship 6.9 MW

Ice class IA Super

Power 6900 kW (ice class minimum)

Bow angle φ1 25o

Length 152 m

vow 13.4 kn

fj 0.8728

fi 1.0650

EEDI 12.46


3. Ice capable ship 7.8 MW

Ice class IA Super


Bow angle φ1 40o

Length 148 m

vow 14 kn

fj 0.8651

fi 1.0000

EEDI 13.40


4. Open water ship 8 MW

Ice class IA


27

Bow angle φ1 Bulbous bow

Length 144 m

vow 15 kn

fj 0.9162

fi 1.0000

EEDI 12.82


The ship route is assumed to be from Kemi to Rotterdam, distance is 1200 nm. The route is ice

covered part of the year, from December to April. The ice data used in the study Riska (2010) is

used here. The other assumptions in calculating the annual energy consumption per transported ton

of cargo are:

Icebreaker power use 12000 kW

Open water days 214

Port time 24 h

Power use in ice 85 % MCR

Power use in open water 75 % MCR

Carried cargo one way 19000 t

The calculations start from distances in ice and how much of this is made independently and

escorted. The interim results include the time for each voyage, number of monthly voyages, power

consumption during winter months etc. The detailed calculations are shown in Appendix and the

main results in Table 5.

Table 5. The results of energy consumption calculations. The number of voyages in ice means the

voyages during the winter months.

Ship variant

Annual voyages,

number Transported

cargo [t]

Energy

used

[GWh]

Energy

used per

carried ton

[kWh/t] OW Ice Tot

1. Ice going ship 10 MW 24.7 16.5 41.2 782800 51.54 65.84

2. Ice going ship 6.9 MW 22.6 15.0 37.6 714400 36.72 51.40

3. Ice capable ship 7.8 MW 23.4 15.4 38.8 737200 41.95 56.90

4. Open water ship 8 MW 24.7 16.2 40.9 777100 43.86 56.44

The most energy friendly of the ship variants is the ice breaking ship with a minimum power even if

the open water speed suffers somewhat from the ice breaking bow shape. The ice going ship with

adequate power for almost independent ice operations in the northern Baltic is not energy friendly

as the power used in open water is large. If somewhat smaller power – and thus somewhat lower

open water speed – would be used, the situation would change much. If the power used in open

water would be 8 MW and the corresponding open water speed 14 kn, the energy consumption

would go down to 47.01 kWH/t while the EEDI value (only dwt corrected as the hull is still ice

strengthened) is 12.89 nmdwt

gCO

2 . These results of the energy consumption versus EEDI are shown

in Fig. 5.

28

Fig. 5. The attained EEDI values versus the annual energy consumption.

Somewhat surprisingly the ship with ice breaking hull form but with minimum ice class power is

most energy efficient – this is based on it having the lowest power and needing only a little

icebreaker escort. When taking into account the ice class correction factors, the ship with an ice

bow and the open water ship are equal in the sense of energy efficiency and attained EEDI. The

dual power alternative is interesting as if the power would be restricted to 7 MW, the attained EEDI

would be 11.77 nmdwt

gCO

2 i.e. lower than that of the open water ship.

29

6. POWER REQUIRED BY ICE CLASS

6.1 Minimum Required Power by Ice Class and Maximum Allowed by Attained EEDI

The maximum allowed attained EEDI is stated by the reference lines. If the ship is otherwise fixed

(shape, structure etc.), the reference line value can be regarded as a power limit or speed limit. The

interaction between the minimum power required by ice class is compared with the power limit

given by EEDI reference line in this chapter. The comparison is done using two ships as the basic

ships; MT Jurmo and MV Eira. The comparison is done by designing three variants of each ship

and then varying the ship length, keeping the ship shape the same. The variation of the speed and

deadweight versus ship length is obtained from regression on open water ships in form

d

pp

bpp

Lcv

Ladwt

where the exponents b and d are obtained from regression and the constants a and c are scaled to the

example ships. Thus the data used in the comparison is as follows.

Bulk carrier based on MV Eira

Variants Bulbous bow Ice bow (original) Ice breaking bow

original ship

length L 144 m 148 m 152 m

DWT 20000 20000 20000

v 15 kn 14 kn 13.4 kn

shape factors

L/B 5.8537 6.0163 6.1789

Lpar/L 0.705 0.713 0.668

Lbow/L 0.143 0.153 0.175

L/T 15.95 16.39 16.83

Dp/T 0.554 0.554 0.554

Awf/L2 0.0192 0.0238 0.0329

φ1 90 40 30

φ2 70 40 30

α2 35 30 25

Regression results

dwt = 443.3410409.7 L 443.3410742.6 L 443.3410151.6 L

v = 0876.0706.9 L 0876.0037.9 L 0876.0629.8 L

30

Tanker based on MT Jurmo

Variants Bulbous

bow(original) Ice bow Ice breaking bow

original ship

length L 159 m 168 m 171 m

DWT 25000 25000 25000

v 15 kn 14.2 kn 13.8 kn

shape and size factors

L/B 6.6998 7.0737 7.2000

Lpar/L 0.608 0.660 0.650

Lbow/L 0.120 0.160 0.180

L/T 14.60 15.41 15.69

Dp/T 0.532 0.532 0.532

Awf/L2 0.0141 0.0166 0.0188

φ1 90 40 30

φ2 65 40 30

α2 28 24 22

Regression results

dwt = 363.3310988.0 L 363.3310821.0 L 363.3310773.0 L

v = 1978.0504.5 L 1978.0154.5 L 1978.0991.4 L

The power limit according to EEDI is calculated from the requirement that EEDI < Reference line.

Inserting the values, the following requirement for power is obtained

af

bfvDWTRLP

j

i

0.6548.443

0.654

where the power of auxiliary engines is denoted as PAE = aPME + b. The minimum power required

by each ice class is calculated using the shape and size factors given in the tables above. The results

of the power values are shown in Figs. 6. where also the ice class coefficients fi and fj have been

used. In most cases the maximum power allowed by EEDI reference line is below the requirement

of the highest ice class. This means that the requirement for the minimum power given by the ice

class and the maximum power allowed according to the EEDI reference lines contradict.

31

Bulk carrier, bulbous bow

Length LPP [m]

0 50 100 150 200 250 300

Pow

er

[kW

]

0

10000

20000

30000

Ice class minimum, IA Super

Ice class minimum, IA

Ice class minimum, IB

Ice class minimum, IC

EEDI maximum, IA Super

EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

Bulk carrier, ice bow

Length LPP [m]

0 50 100 150 200 250 300

Po

we

r [

kW

]

0

5000

10000

15000

20000

25000

30000Ice class minimum, IA Super





EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

Bulk carrier, ice breaking bow

Length LPP [m]

0 50 100 150 200 250 300

Pow

er

[kW

]

0

5000

10000

15000

20000






EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

Tanker, bulbous bow

Length LPP [m]

0 50 100 150 200 250 300

Po

we

r [

kW

]

0

5000

10000

15000

20000






EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

Tanker, ice bow

Length LPP [m]

0 50 100 150 200 250 300

Po

we

r [

kW

]

0

5000

10000

15000

20000






EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

32

Tanker, ice breaking bow

Length LPP [m]

0 50 100 150 200 250 300

Pow

er

[kW

]

0

5000

10000

15000

20000






EEDI maximum, IA

EEDI maximum, IB

EEDI maximum, IC

Fig. 6. The minimum power required by each ice class and the maximum power allowed by the

EEDI reference line for each of the six different ship variants.

6.2 Analysis of Two Ice Breaking Ships

The above analysis of the required engine power in view of ice breaking capability illustrates the

problem of fulfilling at the same time the required minimum engine power in view of the ice

breaking capability and the maximum engine power in view of limiting the emissions. In order to

gain some insight on the question, two special ships are analyzed briefly. The first ship to be

analyzed is the MT Tempera (or her sister ship MT Mastera). These ships are so called dual mode

ships which are intended to sail stern first in heavier ice. The other ship type is the Uikku-class

product tankers. These were designed to operate independently in heavy ice – the experience from

these ships showed that only under extreme ice conditions in the Baltic these ships needed

icebreaker escort. Two of the Uikku-class tankers were converted to Azipod propulsion but here the

original ships are analyzed.

The MT Tempera main particulars are:

DWT 106208 dwt

Lpp 237.59 m

B 44 m

T 14.5 m

v 14.5 knots

PD 16000 kW

fj = 0.771 fj0 = 0.762

fi = 1.041 fi0 = 1.041

These values give the attained EEDI = 3.743 while the reference line values are

Ph 0 4.297

Ph 1 3.867

Ph 2 3.438

Ph 3 3.008

33

Thus the ship fulfills the Ph 1 requirement. The open water power of similar tanker is about 12 MW

which gives an attained EEDI of 3.692; if further the deadweight ice class correction factor is taken

into account the attained EEDI is 3.547 – this is close to the Phase 2 reference line. If the restriction

of the open water power would be to 10 MW (and the open water speed would be 13.6 knots), the

attained EEDI would be 3.151 i.e. closely fulfilling the Phase 3 requirement. These observations

suggest the use of two power ships.

The Uikku-class tankers have an ice breaking bow and high power. The ships have an ice class IA

Super. The main particulars of these ships are:

DWT 16420 dwt

Lpp 150.0 m

B 21.5 m

T 9.5 m

v 17.0 knots (an estimate at 75 % PME)

PME 11500 kW

fj = 0.730 fj0 = 0.526

fi = 1.210 fi0 = 1.435

These values give the attained EEDI = 12.091 (using LNG fuel 9.828) while the reference line

values are (the Phase 0 does not apply to tankers below 20000 dwt):

MEPC 62/6/4 MEPC 58/4/8

(Ph 0 10.686) (12.709)

Ph 1 9.857 (reduction 7.76%) 11.723

Ph 2 9.027 (reduction 15.5%) 10.735

Ph 3 8.198 (reduction 23.3%) 9.749.

The power required by the ice class IA Super is about 4500 kW. This power gives the power ice

class reduction factor of fj = 1.0 and 75% of this power gives an open water speed of about 12.3 kn.

Thus the attained EEDI is, using the minimum power that the ice class allows, 8.787. This value

shows that with minimum ice class power MT Uikku would fulfill the Phase 2 requirement but not

the Phase 3. Use of LNG fuel is required to meet the Phase 3 EEDI requirement. It can be noted in

this context that the power that is required to break about 50 cm thick ice (limit thickness) is about

3300 kW for MT Uikku. The results of the full analysis of Uikku-class tankers is shown below.



factors

Original 12.091 - 0.730 1.210 19.573 38.2 % 17.0 kn/11.5MW

ship

Min IAS power 8.787 -27.9% 1.000 1.210 10.63 17.4% 12.3 kn/4500kW

Dprop 8.391 -31.2% 1.000 1.210 10.15 17.4 % 12 kn/4192 kW

Power IAS min

Nozzle 7.953 -34.8 1.000 1.210 9.625 17.4% 10.6 kn/3510 kW

Power IAS min

34

NOTE:

→ L/B is already about 7 i.e. it is not possible to reduce breadth;

→ The power and speed especially with nozzle get unpractically low; thus the use of minimum

is not realistic;

→ The ice power with nozzle / Dprop reduced are similarly too low?

→ The ships have an icebreaker bow, thus it is not possible to reduce stem angle

→ Nozzle is estimated to reduce ice power 22% at 5 knots

→ Propeller dia change from 5.45 to 5.85 m

35

7. CONCLUSION

The focus of the present study is on how the energy efficiency regulation based on the attained

Energy Efficiency Design Index (EEDI) influences the ice class ships. The EEDI regulation acts as

a maximum limit for the propulsion power (and naturally speed) of ships while the ships that must

sail in ice need at least some minimum power in order to proceed in ice – these circumstances may

lead to a conflict between ice performance requirements and energy efficiency requirements. This

conflict is clearly shown to exist when the minimum power required by the Finnish-Swedish Ice

Class Rules are compared with the power allowed by the comparison of reference lines and the

attained EEDI. In most cases the power required by the highest ice class is much above the one

allowed by reference lines.

The situation is noteworthy for the Finnish merchant ship fleet as only the container ships (3 ships)

will fulfill the Phase 3 requirements – 29 Finnish ships will fall under the EEDI regulation. Even in

the beginning phase (Phase 0) 3 ships out of 9 will not fulfill the requirement for attained EEDI.

This naturally is only a study as the EEDI regulation will be applicable to new ships only.

The question of what is the most energy efficient mode of winter navigation was investigated. Here

especially the balance between ships navigating independently or using extensively icebreaker

escort was addressed. Several options was investigated (open water hull form requiring much

icebreaker escort, ice breaking bow with moderate power requiring some icebreaker escort and ice

breaking bow with good ice breaking performance). The most energy efficient single mode was the

ice breaking bow with a moderate power. Here also the possibility to use two powers; high ice

breaking power in ice and moderate open water power with slightly lower open water speed during

the summer season. This proved to be the most energy efficient mode of transport.

As the Finnish ships do not fulfill the required limits for EEDI, a study how to influence the

attained EEDI value by some design changes was made. The study was made by analyzing two

example ships; MT Jurmo (a 25000 dwt tanker) and MS Eira (a 19600 dwt bulk carrier). Several

changes in the design was checked but it was noted that not even applying all of them did bring the

attained EEDI below the Phase 3 reference line – only when gas as a fuel (LNG) was used, did the

attained EEDI get below the Phase 3 reference line for the tanker but not even then for the bulker.

The analysis shows that the impact of the EEDI regulation will be large for the Finnish winter

navigation system. If the ice breaking power is going to be restricted, more icebreakers are needed

to keep the wintertime sea transportation continuous and safe. This will most probably lead to

higher fairway taxes as well as an environmentally inefficient transportation system.

36

REFERENCE

Riska, K. 2010: The Influence of Ship Characteristics on the Icebreaker Demand. Study made to the

Finnish Transport Safety Agency and the Swedish Maritime Administration, 19 p. [Also presented

in Ice Day 2010, Kemi 10-11.2.2010]

37

APPENDIX

Calculation of energy consumption for the ship variants (energy use not corrected for the actual

power i.e. full power used always)

1. Ice going ship 10 MW

Month

12 1 2 3 4

Distance nm

/ speed kn

Independent 30 / 14 70 / 13 150 / 10 200 / 8 210 / 8

Escorted 0 0 0 20 / 12 20 / 12

Open water 1170 / 15 1130 / 15 1050 / 15 980 / 15 970 / 15

IB waiting time [h] 0 0 0 1 1

Time in one direction [h] 80.1 80.7 85.0 93.0 93.6

Visits per month 3.57 3.55 3.08 3.18 3.09

Energy use in ice [MWh] 153 382 924 1823 1849

Energy use in OW [MWh] 5569 5349 4312 4155 3996

2. Ice going ship 6.9 MW

Month

12 1 2 3 4

Distance nm

/ speed kn

Independent 30 / 13 70 / 11 120 / 8 170 / 7 180 / 7

Escorted 0 0 30 / 12 50 / 12 50 / 12

Open water 1170/13.4 1130/13.4 1050/13.4 980/13.4 970/13.4



Visits per month 3.27 3.24 2.78 2.84 2.83



3. Ice capable ship 7.8 MW

Month

12 1 2 3 4

Distance nm

/ speed kn

Independent 30 / 11 70 / 9 80 / 7 120 / 6 120 / 6

Escorted 0 0 70 / 12 100 / 12 110 / 12

Open water 1170 / 14 1130 / 14 1050 / 14 980 / 14 970 / 14



Visits per month 3.37 3.31 2.87 2.99 2.89



38

4. Open water ship 8 MW

Month

12 1 2 3 4

Distance nm

/ speed kn

Independent 30 / 9 50 / 8 40 / 7 50 / 6 60 / 6

Escorted 0 20 / 11 110 / 10 170 / 10 170 / 10

Open water 1170 / 15 1130 / 15 1050 / 15 980 / 15 970 / 15



Visits per month 3.53 3.43 2.98 3.16 3.06



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