the alternative fuel options, is there another fuel option to consider in the interim?
Possibly. A transitional fuel created by using additives or blending other products with traditional fuel or LNG (which is more readily available now than other alternative fuels) might be an option for reducing vessel GHG emissions while more permanent solutions are considered. An example is LNG with 20% hydrogen. Different transitional fuel choices are likely to be available depending on the vessel and trade. Such transitional fuels may require modifications to the vessel and carry their own risks
22. Should shipowners consider contractual clauses to address carbon emissions regulations and alternative fuels?
The EEXI/CII regulations, the use of alternative fuels, and other environmental regulations towards shipping’s decarbonisation are likely to impact the performance of both existing and future contracts and the traditional rights and obligations of the parties involved. Commercial and legal challenges are likely to emerge and create disputes which are varied and complex.
Shipowners should be discussing with their counterparts over the allocation of responsibility, risks, and associated costs in terms of compliance with the various environmental proposals and regulations currently discussed amongst the industry and those that will emerge. Collaboration would be advisable so that a strategy is agreed with regard to compliance, enforcement, sanctions, and associated commercial consequences. In the same direction, the parties to the shipping contractual chain should consider and address within their contracts the risks and exposure connected to third party claims as well as any impact on insurance coverage. Other problems which may arise could be in terms of alternative fuels’ availability in the ports around the world; a carefully considered clause could reduce potential disputes between the parties.
21. What are some of the technologies or vessel modifications that shipowners can consider in addition to or apart from the use of alternative or transitional fuels? Many emerging technologies and potential vessel modifications are being considered including the following:
Energy efficiency technologies (EETs)
Hull optimisation focuses on minimising the wave resistance and friction between water and hull. The reduced frictional resistance increases energy efficiency of the ship, particularly at reduced speeds. Below are ways in which hull hydrodynamic performance may be improved:
Hull form optimisation
▬ Fore body (bow) optimisation ▬ Aft body optimisation ▬ Appendage Resistance
Optimisation measures are generally applied on new-built ships but also in the retrofitting of existing ships. However, it is important to understand in detail the ship’s performance and its operating profile before considering any design modification. Usually, a comprehensive series of model tests and computational fluid dynamic (CFD) assessments are required in such cases. When considering hull form optimization, it is beneficial to include sister ships in the CFD analysis to reduce the cost for the fleet.
Hull coatings
One way of lowering the frictional resistance is to improve the smoothness of a hull by means of coatings that reduce fouling. In recent years there has been a lot of development in the coating technology, e.g. introduction of hydrogel, a component that traps a microscopic layer of water on the coating’s surface, smoothing the water flow around the hull.
The use of hydrogel containing coatings makes the surface of the hull behave like a liquid on a microscopic level. This not only deters fouling from occurring in the first place, but also significantly reduces hull friction.
Air lubrication
Air lubrication is a method to reduce the frictional resistance between the ship’s hull and water using a sheet of air or air bubbles. This saves energy and cuts down on fuel consumption. An automation system regulates the compressors/blowers depending on speed. In ideal situations, an air injection system can achieve up to a 15% reduction of CO2 emissions together with significant fuel savings.
As compared to ships with v-shaped bottoms, this system is more effective on flat bottoms as the air on a v-shaped bottom will flow away more easily than on a flat bottom.
Propellers and rudders
Propellers and rudders
Electric (battery powered) propulsion
Numerous devices have been designed for improving the ship’s energy efficiency by recovering as much as possible of the rotational energy in the flow from the propeller, or to provide some pre- or post-rotation of the in-flow into and after the propeller to ensure best performance.
Numerous devices have been designed for improving the ship’s energy efficiency by recovering as much as possible of the rotational energy in the flow from the propeller, or to provide some pre- or post-rotation of the in-flow into and after the propeller to ensure best performance.
In recent years, pure battery-electric propulsion, using lithium ion (Li-ion) batteries, has been successfully applied on small, short-sea vessels.
The potential for batteries in combination with a two-stroke main engine in a hybrid system is being evaluated for larger ocean-going vessels.
64 | The Report • September 2022 • Issue 101
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128
