"Bunker Fuels in the Era of Clean Shipping" Dr Diamantis Andriotis, Technical Manager, Stealth Maritime Corporation SA
Contribution of shipping to GHG emissions In accordance with the updated 2000 IMO GHG Study on greenhouse gas emissions from ships, titled: Second IMO GHG Study 2009 international shipping is estimated to have emitted 870 million tonnes, or about 2.7% of the global emissions of CO2 in 2007. However, it has to be mentioned that these numbers can be significantly changed if we consider that the world fleet capacity has been increased by 30% until 01JAN11 and with the currently existing orders for new buildings it will be further increased by 35% by the end of 2012.
Shipping Facts Ships transport accounts for 80-90% of all goods traded worldwide The Current world fleet is comprised by 56,905 vessels having a capacity of 1,350 m. Dwt. Five percent of total world oil consumption - about 140 million tonnes. Three percent of the oil based CO2 production globally - 850 million tonnes of CO2 annually Two to three percent of total world consumption of fossil fuels. Thirteen percent of the global fuel based NOx production Two to five percent of the global SOX emissions
Energy efficiency Transport distance for 1 ton cargo per kg GHG emissions Air plane Heavy truck Ro-ro ship Freight train Container ship General cargo ship Product tanker Bulk carrier VLCC tanker 2 9 30 41 54 73 91 217 236 Source: Danish Shipowners Association 0 50 100 150 200 250 km Whatever is the diagram we choose it can safely be concluded that Shipping is the most energy efficient and environmentally friendly mode of transport. Moreover the fact that is energy efficient makes it also cost effective and this is why it has the greatest share in trading.
Source: NTUA 2008 Energy-EmissionsEmissions efficiency
BUNKER FUELS and SMALL LPGCs SPEED: 11 13.5 kts, MAX. abt. 14 CONSUMPTION: 9 13 MT/DAY (HFO) + abt. 1MT/DAY (MDO/MGO) OPEX: abt. USD 3,00/DAY B-E: abt. USD 5,500/DAY CR: abt. USD 8-12k /DAY Ship s Values: abt. USD 8-25 mil. Taking an average consumption of 11MT/DAY the daily fuel cost can be between USD 9,000 to 12,000 /DAY (HFO: USD 750/MT, MDO: USD 1,000/MT) This is almost 3 times the OPEX, 2 times the B-E, equal to the CR and in abt. 6 years of trading equals the ship s value.
Energy efficiency-engine efficiency Although Marine Diesel Engines are highly efficient there is still potential to be further developed, become more environmentally friendly and maximize the fuel usage. Source: Wartsila
A. New Orders
Future emissions limits IMO NOx Limits Tier I applies to vessels built from 2000 onwards. Tier II applies to vessels built from 2011 onwards. Tier III will be applied to vessels built from 2016 onwards when trading in NECAs. Nitrogen Oxides (NOx) are formed during the combustion process within the burning fuel sprays. NOx is controlled by local conditions in the spray with temperature and oxygen concentration as the dominant parameters. A rule-of thumb suggests that a change of 100 C in combustion temperatures may change the NOx amount by a factor of 3. Source: IMO & MAN DIESEL
Future emissions limits IMO SOx Limits Emissions of SOx originate in sulphur that is chemically bound to the fuel hydrocarbon. When the fuel is burned, the sulphur is oxidized to SOx (mainly SO2). In order to reduce SOx emissions, it is necessary to use a fuel with lower sulphur content or to remove the SOx that is formed in the combustion process. Source: IMO
Future emissions limits Efficiency Indexes Energy Efficiency Design Index The EEDI provides a specific figure for an individual ship design, expressed in grams of CO2 per ship s capacity-mile (a smaller EEDI value means a more energy-efficient ship design) and calculated by the following formula based on the technical design parameters for a given ship: Source: IMO Main Engines Auxiliary engines + Shaft motors + energy efficient technologies e.g. Waste heat recovery + future innovative energy mechanical efficient technologies in relation to propulsion The EEDI is a non-prescriptive mechanism that leaves the choice of what technologies to use in a ship design to the stakeholders as long as the required energy efficiency level is attained enabling the ship designers and builders to use the most cost efficient solutions.
Future emissions limits Efficiency Indexes Energy Efficiency Operational Indicator The EEOI enables continued monitoring of individual ships in operation and thereby the results of any changes made to the ship or its operation. The actual CO2 emission represents total CO2 emission from combustion of fuel on board a ship during each voyage, which is calculated by multiplying total fuel consumption for each type of fuel (distillate fuel, refined fuel or LNG, etc.) with the carbon to CO2 conversion factor for the fuel(s) in question (fixed value for each type of fuel). In order to promote best practices for fuel-efficient operation of ships, the MEPC is considering the introduction of a Ship Efficiency Management Plan (SEMP). The SEMP presents a framework for a ship to address energy-efficient operation by monitoring performance and considering possible improvements in a structured fashion. A SEMP could be developed by the ship operator or other relevant party, such as a ship charterer.
Reduce vessel s speed (Slow Steaming) Reducing vessel s speed by 4knots reduces power requirement almost by 50% Source: MAN B&W 2008 Although it is difficult to provide a cost for this solution, it is expected to be minor compared to the savings on fuels. For older engines there might be some modifications that can cost roughly USD 50,000. Also extra care has to be given in EGR cleanness. Example of reduced fuel consumption at low load operation for large container vessels with 12K98MC-C6, SMCR = 68,520 kw at 104 r/min Eng. Power [%SMCR] 90 30 SFOC [g/kwh] 167.5 174.0 Fuel consumpt. [t/24h] 263.3 101.6 Operating Time [h/week] 168 168 Fuel consumpt. [t/week] 1843.3 711.1 Ship Speed [knot] 25 18.5 Sailed Distance [n mile/week] 4200 3108 Fuel consumpt. per n mile [kg/n mile] 439 229 Relative fuel cost per n mile [%] 100 52.1 Heavy fuel price (380 cst) 10000n mile trip cost SAVING $150 $685,000 $343,000 $315,000 $200 $878,000 $458,000 $420,000 $250 $1,097,000 $572,500 $525,500 $300 $1,317,000 $687,000 $630,000 $600 $2,634,000 $1,374,000 $1,260,000 Reducing vessel s speed requires efforts from both Chartering and Operation department in order to have the ship at its destination on time!
Installation of electronically controlled engines (ME) Example of reduced fuel consumption at low load operation for large container vessels with 12K98MC-C6 and 12K98ME-C6 Eng. Type at 30% SMCR Eng. Power MC ME SFOC [g/kwh] 174.0 171.2 Fuel consumpt. [t/24h] 101.6 92.1 Operating Time [h/week] 168 168 Fuel consumpt. [t/week] 711.1 644.3 Ship Speed [knot] 18.5 18.5 Sailed Distance [n mile/week] 3108 3108 Fuel consumpt. per n mile [kg/n mile] 229 207 Relative fuel cost per n mile [%] 52.1 47.3 Source: MAN B&W 2008 Heavy fuel price (380 cst) 10000n mile trip cost SAVING $150 $343,000 $310,000 $33,000 $200 $458,000 $414,000 $44,000 $250 $572,500 $517,500 $55,000 $300 $687,000 $621,000 $66,000 $600 $1,374,000 $1,242,000 $132,000 It has to be mentioned that the above figures are for engines optimized at 100% load. ME engines have part load modes embedded able to reduce SFOC by 3-4 g/kwh. The Cost for ME for a VLCC is $500,000. It is expected that this cost has been absorbed after 2-2.52.5 years of operation
Pre-swirl Stator and propeller Cleaning VLCC FITTED WITH PSS By directing the flow to swirl in the opposite direction of propeller rotation, energy that is normally lost in wake rotation is now recovered. This increases thrust by an additional 4-6%. Pre-swirl stators improve the in-flow angles and insure a more uniform inflow to the propeller thus reducing also Vibrations Undertaking regular propeller polishing every six months increases Propeller s efficiency by 2-4%. The cost for a VLCC is estimated to $30,000 annually while the gain is significantly more It is claimed that It accelerates speed performance by 0.2 knots and reduces fuel consumption, and therefore emissions, by 4-5%, which means that if the cost for a N/B VLCC is $750,000, the pay back time is less than 2 years Source: DSME-MTM.
Clean Fuel and/or Exhaust after-treatment treatment systems? As an alternative to using low sulphur fuels, an exhaust gas cleaning system can be employed to reduce the level of sulphur dioxide (SOx). Two main principles exist: open loop sea water scrubbers and closed loop scrubbers. Both scrubber concepts may additionally remove limited amounts of NOx and PM. Both systems tend to cool the exhaust and may be difficult to combine with a SCR exhaust gas treatment system which relies on high exhaust temperatures and low sulphur and PM content in the exhaust. It is also possible to build hybrid systems that can operate either with sea water or in closed loop depending on needs. Source: IMO
Clean Fuel and/or Exhaust after-treatment treatment systems? Sea water scrubbing An open loop sea water scrubber washes the engine exhaust with sea water to reduce SOx emissions. This reaction relies on the alkalinity of the sea water. Ocean alkalinity is usually constant and high, however alkalinity in coastal areas, ports, rivers and estuaries is mainly affected by the different drainage areas of the inflowing rivers, resulting in large variations in the chemical quality. Therefore, a sea water scrubber will not be equally effective in these areas. The sea water scrubber relies on a continuous flow of water through the system, thus generating a continuous effluent flow that is too large to store on-board. Pumping power to move the seawater has been estimated to about 2% of engine MCR. The IMO Scrubber Guideline provides limits for the effluent including Polycyclic Aromatic Hydrocarbons (PAH), turbidity, ph, nitrates and other substances. Port state requirements for effluent discharges will have significant impact on the possible use of sea water scrubbers. Source: IMO & WARTSILA
Clean Fuel and/or Exhaust after-treatment treatment systems? Closed loop scrubbers In closed loop scrubbers, fresh water with an addition of caustic soda or other suitable chemical is circulated and contacted with the exhaust to remove SOx. The main benefit is that this system is independent of the sea water alkalinity and may thus be used in all areas. In time, the circulating water will become contaminated beyond filtering, hence a small portion (the bleed-off ) of the scrubbing water flow is conducted to the treatment unit. The bleed off flow is not large and it is possible to periodically operate the system without discharging any wash water overboard. However, discharge or landing of residues will be an issue with this scrubber concept also. Parasitic load for moving water is estimated to < 1% MCR. Source: IMO & WARTSILA
Clean Fuel and/or Exhaust after-treatment treatment systems? Scrubber Clean Fuels OR Distillate Fuels e.g. MGO Bio Fuels (not really since availability is limited) LNG Options to comply with IMO SOx regulation, both globally and in Emission Controlled Areas (ECAs) 1. Continuous operation on low-sulphur HFO or destillate fuel 2. Two different fuel qualities on board, switching over when entering ECAs 3. Running on high-sulphur HFO in combination with exhaust gas aftertreatment: Scrubber / Flue Gas Desulphurization Source: IMO & WARTSILA
Clean Fuel and/or Exhaust after-treatment treatment systems? MGO MGO can be an option but at a high cost. Table I: Average bunker prices in US$/ton, July 2010 Grade IFO380 IFO180 MDO MGO Fujairah 453 466-728 Houston 440 459 665 - Rotterdam 438 461-662 Singapore 447 457 642 655 The global switch from 3.5% residual fuel to 0.5% is a dramatic change. It is difficult to imagine such a transition happening overnight, and significant investments must be made either in refineries or in abatement technology well in advance of the 2020 deadline. Presently, the industry appears caught in a deadlock where ship owners appear to rely on refiners to solve the issue while refiners appear to rely on ship owners to install scrubbers. Source: CIMAC Paper No. 13, IMO & WARTSILA
Clean Fuel and/or Exhaust after-treatment treatment systems? LNG The use of natural gas is another possibility to reach the IMO limits in respect of NOx and SOx in one step. The fuel is practically sulphur-free and leads to significant lower NOx-emissions when a lean premixed combustion is utilized. The drawback of that fuel is the significant larger amount of storage room in a range of roughly 2.5 to 3 times compared to fuel oils. Therefore, the range of full gas-fuelled ships will be limited in respect to actual designs with conventional propulsion. The use of dual-fuel engines will be a way to find a good Compromise of low emission in ECA and full range outside. Nevertheless, gas-fuelled engines will take its share of the propulsion systems of the future. Source: CIMAC Paper No. 274, IMO, WARTSILA & MAN DIESEL
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