Energy-Savings Basics For The Maritime Industry - An Overview
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Transcript of Energy-Savings Basics For The Maritime Industry - An Overview
Dr. George Gougoulidis
Introduction (CSR, Energy, emissions and the main drivers, Research projects)
Regulations Operational measures Tech measures Hull &superstructures Design Coatings Air lubrication
Propulsion components Renewable energy Main engines & Alternative fuels Machinery
Future considerations
“A concept whereby companies integrate social and environmental concerns in their business operations and in their interaction with their stakeholders on a voluntary basis”. (original European Commission definition)
New definition: “the responsibility of enterprises for their impacts on society”.
To fully meet their corporate social responsibility, enterprises should have in place a process to integrate social, environmental, ethical, human rights and consumer concerns into their business operations and core strategy in close collaboration with their stakeholders
The interest of many stakeholders has increased, leading to pressure on the maritime industry
Gain a competitive advantage Strengthen its brand, image, reputation Achieve higher sales Increase employee pride and loyalty, motivation Realize cost savings Enjoy easier access to financing / Socially responsible investing Reduce risk Avoid Unethical business practices Avoid potential negative impacts on local communities Avoid exposure of poor performance
Energy Savings
Cost Savings Ship Owners/Operators
Environmental Benefits Everyone
Financial Crisis
Regulations (IMO)
Head seas, Beaufort 6
Second IMO GHG Study 2009
Second IMO GHG Study 2009
EEDI = Energy Efficiency Design Index EEOI = Energy Efficiency Operational Index SEEMP = Ship Energy Efficiency Management Plan CEEMP = Company Energy Efficiency Management Plan IEEC = International Energy Efficiency Certificate KPI = Key Performance Indicator MBM = Market‐Based Measures MBI = Market‐Based Instruments
IMO Measures
Technical
EEDI
Operational
SEEMP/EEOI
Economic
MBM/MBI
The Energy Efficiency Design Index (EEDI) is a measure of ships energy efficiency
In force since 1 Jan 2013 Applicable to ships over 400 GT Not applicable to ships with diesel‐electric, turbine or hybrid propulsion
EEDI for new ships Contracted 1 Jan 2013, or Keel‐laid 1 Jul 2013, or Delivered 1 Jul 2015
Flag State may waive the EEDI for up to 4 years
Attained EEDI & Required EEDI for new ships new ships undergone a major conversion new or existing ships undergone a major conversion
Attained EEDI Required EEDI
Environmental cost = Emission of CO2 Benefit = Cargo capacity transported a certain distance
societyforBenefitcosttalEnvironmenindexdesign efficiencyenergy Attained
To establish a mechanism for a company and/or a ship to improve the energy efficiency of a ship's operation
Mandatory for all ships to have one, but not a specific form
Existing ships by first intermediate or renewal survey after 1 Jan 2013
Planning
Implementation
Monitoring(EEOI)
Self‐evaluation & improvement
An assessment tool of the efficiency of a ship with respect to CO2 emissions
Voluntary Defined as the ratio of mass of CO2 emitted per unit of transport work
MEPC recognized that technical and operational measures not sufficient to satisfactorily reduce the GHG emissions
MBMs place a price on GHG emissions and serve two main purposes: provide an economic incentive for the maritime industry to reduce its fuel consumption offset in other sectors of growing ship emissions
Improved voyage planning
Weather routeing Just in time Speed optimization Optimized shaft power Optimum trim Optimum ballast Optimum propeller and
propeller inflow considerations
Optimum use of rudder and heading control systems (autopilots)
Hull maintenance Propulsion system Propulsion system
maintenance Waste heat recovery Improved fleet management Improved cargo handling Energy management Fuel Type
Improve
Technology
Exterior of ship
Hull
Superstructure
Propulsion components
Interior of ship
Main engines
Machinery
Operations
Hull & Superstructure Design Coatings Air lubrication
Renewable Energies Propulsion components Propeller Rudder ESDs
Main engines Derating Longer stroke Turbocharger cutout Cylinder cutout Tuning Common rail Alternative fuel
Machinery Shaft generator Hybrid auxiliary power
generation (fuel cells) Waste heat recovery
Voyage planning Slow steaming ‐ Speed optimization Weather routeing Just in time Optimized shaft power Optimum trim Optimum ballast Optimum use of rudder and heading control systems Hull maintenance Propulsion system maintenance (engines, propellers) Training of personnel
It can encompass other measures such as weather routeing, just in time, speed optimization
There are various software available for planning purposes
Pre‐voyage analysis & planning Deploy ideal vessel to each route Design best routes
Plan for Minimizing time: recommend optimum route to meet earliest arrival time. Minimizing fuel consumption: recommend the optimum route and power to arrive on time with minimum fuel consumption Minimizing cost: recommend the optimum route and power to arrive on the basis of minimum cost
En route real‐time updates Post‐voyage assessment and feedback
Speed optimization vs speed reduction Reducing ship speed effectively reduces fuel consumption
Propulsion power vs. speed is a third power relation
A study conducted by IMO proved that optimal speed reduction is between 10‐20%
Cost effectiveness of 10% superior to 20%
Optimization should be carried out for the “off‐design” conditions
Originally excellent hull forms, optimized for design speed and draft, may show poor performance when sailing at lower speeds, especially in a partial loading condition
Optimum speed means the speed at which the fuel used per tonnemile is minimum
It does not mean minimum speed Sailing slower than optimum speed will consume more fuel
Slow steaming remains controversial, especially with older engines not originally designed for the practice
However, it remains the easy solution of coping with unfavorable market conditions
Overcapacity – low freight rates ‐ slow steaming will become even slower and even more prevalent
Use real‐time data of the physical environment to choose the optimal route through calm areas
Weather routeing can be applied to all ship types and trade areas
The increase of resistance caused by heavy weather depends on the current, the wind, and the wave size
The resistance in head seas can increase by as much as 50‐100% of the total ship resistance in calm weather
Early communication with port authorities to ensure the exact time of berth availability and plan for optimum speed to arrive just in time
Less turnaround time in port allows for speed reduction while underway
Applies to ships with scheduled operations, such as ferries and container vessels
Measures for improvement include: Better maneuvering capabilities of the ship Increased cargo flow by using sophisticated ship systems, such as ramps, lifting equipment
Increased cargo flow due to improved port loading/offloading systems
The provision of shoreside electrical power to a ship at berth while its auxiliary engines are shut down
Trim has an immediate effect in resistance
For any given draft there is a trim condition that gives min resistance
Several systems in the market Collect data from the vessel's
automation and navigation systems to optimize trim
GreenSteamOptimizer, Eniram’sDynamic Trimming Assistant, etc
Potential savings up to 4%
Autopilots can achieve fuel savings by reducing the distance sailed “off‐track”
Better course control through less frequent and smaller corrections will minimize losses due to rudder resistance
Hull Regular in‐water inspection of the condition of the hull
Monitoring of the fouling Monitoring of the coatings’ condition Cleaning of the hull when required Docking intervals planning Complete removal and application of new coatings for reduction of roughness
Propeller Use divers to polish the propeller in regular intervals while ship is in‐service
New standard for hull and propeller performance under development
The development of the standard was discussed inTokyo in November 2013
Hull performance monitoring is difficult because several parameters have to be considered (draft, trim, speed, seaway, wind, etc)
Physical roughness
Macro
Welds
Corrosion
Plate waviness
Plate laps
Mechanical damage
Micro
Minor corrosion
Steel profile
Coatings condition
Biological roughness
Macro
Animal fouling
Weed fouling
Micro
Slime fouling
Increase in Resistance @ 15 kt Increase in Resistance @ 30 kt
In absolute terms propeller roughness is less important than hull roughness
In terms of energy loss per unit area propeller roughness is significantly more important
Typical cleaning intervals should be: 6 months for propellers 2 months for hull (depends on coating type)
Measured with Rubert Scale Underwater cleaning can smoothen the propeller by 2 grades of the Rubert scale
Frequent propeller cleaning (every 1 or 2 months) can be easily done using a soft brush and abrasives
Enough to keep a propeller at Rubert Grade A or B
Cleaning takes less time than polishing A large propeller can be polished in ~4h With regard to the frequency of propeller polishing there is a consensus of: “little and often” by experienced and specialized personnel
Cost of propeller cleaning (brush & abrasives) 15‐20% less than full polishing with grinding or polishing discs
Follow manufacturers’ instructions on maintenance schedule
Condition based maintenance Maintenance is performed based on information received by the equipment and on evaluation of this information by experts
Persuade the personnel of the necessity of energy savings
Create a culture of fuel saving, with an incentive or bonus based on fuel savings
Alter the routine Shut down AC Plant when the weather is good and use only the blowers
Switch off lights in areas such as cabins, recreation rooms, mess rooms, etc. when not required
Type of resistance % of RT
High speed Low speedFriction 45 90Wave‐making 40 5Eddy 5 3Air 10 2
Fluid Dynamics
Aerodynamics Superstructure
Hydrodynamics Hull / Propulsion components
General Optimize dimensions Reduce weight Minimize ballast
Fore part Optimized bow bulb No bulb Wave piercing bow Flare
Aft part Stern end bulb Skeg Ducktail / stern flap / interceptors
Allow for large propeller
Optimize main dimensions – lines Low wave making resistance → high L/B ratio Low friction →minimum wetted surface, B/Tratio ~ 2.25 for Cb=0.80
Maximize length to reduce resistance Optimize skeg to direct the flow evenly to the propeller
Shaft lines should be streamlined
Flow disturbance from hull openings (bow thrusters, sea chests) should be minimized
Reduce weight, use lightweight materials Increase deadweight scale effect Reduce ballast Use CFD, model testing, sea trials to verify design
SEAHORSE 35 B.DELTA DELTAMARIN
The Environship, of NVC 401 LNG design, is the Eidsvaag Pioner
Rolls‐Royce Bergen B‐Series lean burn gas engines
Rolls‐Royce Promaspropulsion
Optimized bow and hullform shape
Vertical bow ‐maintain speed even in rough seas
By using alternative materials By reducing ballast By optimizing design
Material Density (kg/m3) Yield strength (Mpa)
Steel 7850 235‐390
Aluminum 5083 2650 215
Aluminum 5383 2660 220
Aluminum 5059 (Alustar) 2640 270
Titanium 6Al‐4V (Grade 5) 4430 880
SEA GIANTL = 458.5 M
EMMA MÆRSKL = 398 M
Benchijigua ExpressL=124mAluminum
Visby ClassL=73mCFRP sandwich
Sierra I & II classMax Safe depth=700mCrush depth=915mL=111mTitanium
Developed by University of Michigan It allows water to flow into "trunks" inside the ship's hull, and then to pass out through outlets at the stern
It works by reducing the buoyancy instead of increasing the displacement weight
The first NOBS are being built at Ningbo East Shipyard, China
2×6,500 DWT and 2×4,500 DWT NOBS Bunker Tankers
Designed by XED after 3 years of research
Developed by Namura Shipbuilding and Shipbuilding Research Center of Japan, approved by ClassNK
300,000 dwtVLCC that requires 65% less ballast water to operate safely (30,000 tn)
Based on the NOBS concept that required no ballast water at all
Non‐Ballast Water Ship (NOBS) employed an extremely wide hull, limiting its practical use
MIBS is of standard breadth but employs a flatter bottom than a conventional VLCC and a more angular lower hull
Bow bulbs are common practice in ship design, both for commercial and naval ships
The maturing of the bulbous bow theory and design has resulted in several bulbous bow designs which reduce resistance by 10% or more
Reduction of wave making resistance (through the reductionof bow pressure wave, due to the interaction with thepressure field created by the bulb)
Promoting of uniformity of the flow velocity around the hull(which means reduction of the drag due to turbulent flow andeddy-making resistance)
Reduction of wave breaking resistance at the bow Reduction of pitching motion Increase in frictional resistance
A Stern Flap is an extension of the hull bottom surface aft of the transom
Stern flaps modify the pressure field under the hull afterbody, causing the flow to slow down
Decreased flow velocity → increase in pressure → reduced resistance due to reduced after‐body suction force
Wave heights in the near field stern wave system and far field wave energy are reduced
Additional secondary effects due to lengthening of the hull, and to improved propeller performance
Reduced propulsive power, propeller loading, cavitation, vibration, noise
Mature and proven technology tested since 1989 173 stern flaps installed on US Navy and Coast Guard ships
Cumulated fuel savings $ 665 million 1989‐2011
USS PORT ROYAL CG73 USSARTHURW. RADFORD DD 968
In the absence of a hull fouling control system, a vessel in service, can accumulate up to 150 kg/m²of fouling within 6 months
Total resistance caused by fouling, may increase by 25‐ 50% throughout the lifetime of a ship
The main cost associated with fouling is the increased fuel consumption due to increased frictional drag
The cost related to hull cleaning and painting is much lower than fuel cost
AF coatings
Biocidal
CDP
SPC
Hybrid
Non‐biocidal
Foul Release
STC
Rosin is used for biocide releasing by hydration Thick leached layers → increased roughness(~75μm).
High VOC (55‐60%) Rosin is brittle and can cause cracking and detachment
Film integrity is generally poor Suitable for use in lower fouling areas or short dry‐docking intervals
3 years
Chemical dissolution is controlled by hydrolysis
Thin leached layers (~10‐15 μm). Controlled biocide release which allows a constant rate of leaching over time
Smoother surface Fair mechanical properties – can be damaged Cleaning and re‐coating easy 5 years
Biocide releasing mechanism is a combination of hydrolysis & hydration
Combine SPC acrylic polymer with a certain amount of Rosin
Moderate leached layer thickness (~25‐30 μm) Performance and price between the CPD and SPC
High VOC 3‐5 years (vertical sides ~3 years, flats ~ 5 years)
Do not contain biocide Low surface energy, non‐stick (silicon based) materials are used
Low roughness ~70μm Effective only above a certain speed Not very efficient on slow ships Shear force needed to detach the marine organisms
Soft coating ‐ easily damaged
Hard, inert, non‐toxic coatings Epoxies, polyesters or vinyl esters ‐ some are reinforced with glass flakes ‐ variations include ceramic‐epoxy
Designed for frequent in‐water treatment Their surface improves with routine cleaning Provide protection against corrosion Extremely durable
Cost
Performance
CDP
Hybrid
SPC
FRC
Blowers inject air under the vessel hull Reduces the friction and drag created by the vessel moving
through the water Energy is required to power the blowers, offsetting savings
to some extent
Class NK partnered with Mitsubishi (MHI), Nippon Yusen Kaisha (NYK)
More efficient in low speed, wide and flat bottom vessels
When deep draft, more energy needed to supply the required air
Ideal for heavy‐lift ships, module carriers
Installed in 2011 on module carrier Yamatai, followed by Yamato
Installed in 2012 on the ferry Naminoue (slender hull) and the coal carrier Soyo
To be installed on 2 cruise ships to be built for AIDA Cruises and 3 bulk carriers of ADM
Air layer thickness
Power decrease
Power of blower
Net energy savings
t = 3 mm 5% 2% 3%
t = 5 mm 14% 4% 10%
t = 7 mm 20% 7% 13%
• Semi Spherical Shape (SSS) bow• Reduction in wind resistance = 50%
Nissan PCTC
Based on the Magnus Effect = a spinning object creates a whirlpool of rotating air or liquid about itself.
On one side of the cylinder the flow is assisted by the induced flow of the cylinder. On this side the velocity is increased.
On the other side, the free stream flow is opposed by the induced flow of the cylinder and the velocity is decreased.
Change of the velocity field →change of the pressure field → lift
Developed by Anton Flettner in 1924
Official presentation of Rotor Ship in Hamburg in 1925
Renamed Baden‐Baden and made a successful voyage to New York in 1926
Earth’s average solar irradiance on the surface is approximately 342 W/m2
On average, 30% of this radiation will be reflected back to space due mainly to clouds
The amount of energy captured depends on efficiency and positioning
Current solar cells’ efficiency is about 13%
Tanker, 270 m long and 50 m wide One main engine rated at 18,000 kW, and auxiliary power 1,000 kW
Tanker’s deck area completely covered by solar cells
First vessel car carrier Auriga Leader Followed by Emerald Ace Part of the electricity is generated via solar panels Hybrid electric power supply system 768‐panel 160kW solar generation system Lithium‐ion storage battery system Storage capacity 2.2MWh Used while in port Needs 3 days underway to charge
Length: 199.9 m, Beam: 32.26 m
Aft body flow devices Devices before the propeller Devices at the propeller Devices behind the propeller Combinations of systems
Their purpose is to reduce losses in the ship’s wake‐axial losses (black) rotational losses in the slipstream (blue) hub vortex losses (green) tip vortex losses (red)
Marine Propellers and Propulsion ‐ John Carlton
Vortex generator fins/Safer fins
Mewis duct SchneekluthWake
Equalizing Duct ‐W.E.D. L‐J duct DSME pre‐swirl stator PBCF Post Stator by Samsung
Heavy Industries Vane wheels
Rudder bulb HHI thrust fin Twisted rudder
CRP Contra rotating propeller Tip Rake TR propellers
(Kappel) Ducted propellers Non‐hub vortex NHV
Nakashima propellers
PROMASENERGOPAC
Tip Rake Propellers Kappel Propellers CLT (Contracted and Loaded Tip) Propellers TVF (Tip Vortex Free) Propellers Propellers with end plates
Tip rake suppresses the formation of tip vortices
TR propellers minimize the flow over the tip
Improve the efficiency 3%‐6%
Reduced noise ‐ suitable for submarine applications
No communication between pressure and suction side due to end plates
No formation of tip vortices
Generation of thrust along the entire blade
Improve efficiency 6% ‐ 8%
Nozzles are airfoil shaped rings placed around the propeller
An accelerating duct produces positive thrust and increases the efficiency of heavily‐loaded propellers (up to 20%)
A decelerating duct produces a negative thrust and reduces cavitation & noise
The application of a nozzle increases the thrust at relatively low ship speed
Increased efficiency ~ 6% The after propeller is usually smaller in diameter (cavitation) but higher pitch
Used extensively in torpedoes Increased shafting complexity, maintenance, cost
Podded contra-rotating propeller (CRP) propulsion
Conventional rudders are placed behind the propeller with a symmetrical cross section about the vertical rudder center plane
This arrangement does not consider the fact that the propeller induces a rotational flow that impinges the rudder surface
This results in areas of low pressure on the blade that induce cavitation and cause erosion
Savings 3‐6% for single screwSavings 2‐5% for twin screw
Savings 2‐9%
Variable exhaust valve timing Permanent cylinder cut out improved engine efficiency for slow speed operation 10‐14%
Optimizes cylinder pressure distribution 1‐2% Delta tuning (Wärtsilä) for reduced fuel consumption in the load range that is most commonly used
Tuned for lower consumption at part load Wärtsilä Intelligent Combustion Control ensures optimal firing pressures ‐ fuel reduction 2.5 g/kwh
Longer stroke engines (MAN G‐type) → low rpm → large propeller → high efficiency
S80 engine 78 rpm →G80 engine 68 rpm
Potential savings 4‐7% MAN reports having almost 200 G‐type engines on order (spring 2013)
Cut out of a turbocharger for improved engine efficiency at part & low loads
Potential savings 2‐4%
Consists of a high‐pressure fuel rail feeding individual solenoid/piezoelectric valves
Common Rail controls combustion so it can be optimized at every load
Recovers energy from exhaust gas
Converts thermal energy to electricity for reduced gensetconsumption
Savings up to 12%
76% of the marine fuel used is Heavy Fuel Oil (HFO) which has high sulphur content
The options to comply with the SOxregulations are: Operate on low‐sulphur fuel oil (MDO,MGO,ULSD) Operate on HFO with an exhaust gas treatment system Operate on alternative fuels: LNG ‐ Biodiesel
Lloyd’s Register
Composed mainly of methane, containing small quantities of ethane, propane and butane
To maximize storage capacities, natural gas is usually refrigerated to change its state to a liquid (Liquefied Natural Gas ‐ LNG)
Elimination of SOx Low NOx and particulate emissions Savings from not having to separate and heat HFO
LNG can be used to cool the ship’s HVAC to save AC‐compressor power
Lack of infrastructure and supply chain network Gas providers and bunker suppliers unwilling to invest in infrastructure since there is no sufficient demand – there is no demand since there is no infrastructure
Extremely low temperatures → hazards of cold burns on crew and brittleness on structures
BLEVE due to high expansion ratio ~600:1 (a small volume of liquid can yield a large amount of gas)
High flammability
Wärtsilä 34DF 50DF
MAN Diesel & Turbo 32/40DF (400 kW/cylinder) 51/60DF (975 kW/cylinder)
Otto cycle engines MAN Diesel & Turbo 51/60G
Wärtsilä 34SG & 50SG
Based on vegetable oils (camelina, corn etc.) and animal fat (tallow)
Significantly reduced SOx emissions Lower particle emissions NOx emissions depend on the fuel type Engines may need modifications
Lower thermal value ‐ 5% less output for a 4‐stroke engine
Lower energy content means larger fuel tanks
Biofuel production has not moved to full‐scale
More expensive
Current refers to 2012
Conflict between the biofuel and the food industry
The challenge is to find sustainable feedstocks at a reasonable cost
Additional land to grow crops for biofuels is needed
Built in 2006 Sunk in 2010 Part of the project was to break the world record for circumnavigating the globe using only renewable fuels
The boat's engines were powered completely by biodiesel
In the short term, LNG is relatively easy to adopt thanks to standards and technical knowledge, despite the challenges of building LNG infrastructure
Wind and solar energy are appropriate auxiliary power sources
In the medium and long term, biofuels and synthetic fuels have promise
In the even longer term, hydrogen is seen as an option
Shaft generators driven by the main engines Reduce the need to run auxiliary gen sets Electrical system requires fixed voltage & frequency meaning that engine speed has to be constant
Two solutions: Power take off (PTO) system with frequency control ensuring constant frequency Hybrid system conditioning the power from shaft generator so that the supply to the switchboard remains constant at any engine speed
Shaft generator may be used as a motor providing power to the propeller
Benefit from efficient electric drive for cruise speeds & cost effective mechanical drive for higher speeds
The electric drive allows the Main Diesel Generators (MDG) to provide power for the ship’s electrical load and the propulsion motors
These motors operate as alternators when running on the Main Diesel Engines (MDE) at higher speeds
The result is fewer prime movers, fewer engine running hours and also fuel economy
Pentamaran concept zero‐emission car carrier
WalleniusWilhelmsenLogistics developed the vessel for Toyota for Expo 2005 in Japan
Propulsion by fuel cells, sun, wind and waves
Length = 250 m Beam = 50 m Draught = 9 m Max speed = 20 kt Vehicle capacity = 10,000 cars
Designed by Eco Marine Power Aquarius MRE System Includes solar panels, energy
storage modules, a computer control system and an advanced rigid sail design
Additionally, advanced electrical propulsion system, optimized hull design and waste heat recovery technologies
Possible fuel savings of 40%
Cruise ship concept developed by STX Europe
Reduced Power consumption by 50% CO2 emissions by 50% SO2 by 100% NOx by 90% Ash by 100%
Powered by 4 dual fuel LNG diesel electric gen‐sets
Equipped with an innovative sail system by STX France
Fuel consumption 60%Emissions 80%
Lloyd’s Register – Fairplay
As of Jan 2012: 104,305 ships
UNCTAD ‐ Fairplay
Although the size of the orderbooks is reduced, the number of ships is anticipated to increase in the midterm
Overcapacity is likely to continue for the foreseeable future and beyond 2020
Fuel and operating costs ↑ since 1990, with the exception of a sharp dip in 2009, which was quickly reversed
In order to maintain the shipping industry’s total emissions in levels similar to todays’, more efficient ships have to be built
In the near future, ship efficiency is expected to improve due to: Increasing regulatory pressures on the industry Increasing cost of bunker fuel
How do we define them? Eco‐nomic ~ Eco‐logical Not a revolutionary technology Ambiguous Marketing trick of shipyards to increase their orderbooks???
Shipyard quality makes a difference in operating performance
Analyzed 1298 bulkers of 55‐70,000 tn (dwt) built from 1965 to 2013
Fuel consumption in the last 20 years was pretty flat and on paper at least, many of the modern ships are less efficient than older ones
The big technological improvement of 1975‐88 will be difficult to repeat because the technology has been squeezed so hard over the last 25 years
The big fuel savings come from slower speed which can equally be applied to old and new ships
New eco‐ships consume 28 tn/day compared to 32‐35 tn/day for the old ships yielding an improvement of 15‐20 %
New ships carry a lot of capital costs New ships are unattractive on return on capital over the long term
The market for eco‐ships is immature Charterers reluctant to pay a premium for eco‐tonnage – not persuaded that fuel efficiencies can be delivered as promised
The advantages of eco‐ships are hindered by slow steaming in a down market
Eco‐ships are able to meet tight schedules without the fear of bunker costs
Eco‐ships’ advantage will depend on whether fuel prices remain high
Can we actually
measure the performance?
Plethora of ESDs and strategies
Savings claims of 1‐10%
Combination of ESDs.
Counteract against each
other?
Ecoship: Need or
necessity?
To retrofit ESDs or to scrap?
Manage Measure Know Understand Improve