International Best Practices in Green Shipbuilding Technologies and applications – 2nd part, Prof. Dr. Nikitas Nikitakos
Following our previous presentation in this section a brief overview of several related technologies and applications are presented:
No Ballast System
Ballast water convention by IMO focuses on reducing the transit of sediments and microorganisms of one territory to another through the ballast of ships. Plans of making a “No Ballast Ships” are under progress, since a no ballast ship or similar system can drastically reduce this problem.
LNG Fuel for Propulsion
Liquefied Natural Gas is perceived as the optimal fuel in the shipping industry for the future, since it helps in reducing pollution from ships, especially in the air, and a combination of LNG fuel with diesel oil will lead to efficient engine performance, resulting in fuel saving
LNG Fuel for Auxiliary engine
Auxiliary engines on ships are main sources of power. Moreover they are continuous running onboard vessels. LNG fuel for such engines can drastically reduce air pollution from ships. A small tank for LNG fuel storage can supply enough gas fuel in port to auxiliary engine of a container ship.
Sulphur Scrubber System
Reducing sulphur or SOx emission from the exhaust, is a solution that will be used extensively in the future. This can be achieved by installing an exhaust gas scrubber system wherein the sulphur is washed out from the exhaust gas of the engine resulting in reduction of SOx up to 98% along with other harmful particles.
Advanced Rudder and Propeller System
Advanced designs of propeller and rudder systems have been developed to not only reduce the fuel consumption but also improve the speed of the vessel.
Speed Nozzle
Speed Nozzles are generally used in small supply vessels and tugs to provide power to the ships. Along with new design features of merchant vessels, they can improve the propulsion efficiency of the ship by saving power up to approx. 5 %.
Hull Paint
Applying correct paint at correct hull area can reduce the frictional resistance of the ship resulting in 3-8% of fuel savings. From an environmental perspective, this paint is a step up from other protective boat paints because it usually has no solvents and doesn’t release pollutants.
Waste Heat Recovery System
This system is already in use for quite some time now, but making it more efficient can reduce the fuel consumption of the ship drastically up to 14% of the total consumption.
Improved Pump and Cooling Water System
An optimized cooling water system of pipes, coolers and pumps can result in decreased resistance to the flow. This will lead to savings of up to 20% of electric power of the ship and fuel consumption up to 1.5 %.
Sail and Kite Propulsion System
Sail and Kite propulsion system when used along with the conventional propulsion system can reduce the fuel as well as NOx, SOx and CO2 emissions by a significant amount. This system basically utilizes wind assisted propulsion by flying a gigantic kite from the bow of a ship using the traction developed by the kite to assist in pulling the ship through the water.
Fuel and Solar Cell Propulsion
The fuel cell propulsion utilizes power from a combination of fuel cells, solar cells and battery systems. This helps in reduction of GHG emission to a great extent. Recently, many technologies have come which support the big ships to reduce fuel consumption by utilizing solar panels or rigid sails.
Electric Ships
A recent trend in some types of ships, in order to reduce reliance on fuels like diesel and heavy oil, is to develop electric ships. This combined with the recent developments in energy storage and the use of best practice examples from electrification in other industries has led to advances in ship electrification.
Sandwich Plate System
It is a process of composting two metals plates by bonding it with polyurethane elastomer core. This avoids usage of steel hence makes the structure light weight and less prone to corrosion. This technology can definitely play a good role in green ship recycling process as SPS feature includes superior in service performance and reduced through life maintenance.
Usage of VFDs (Variable-frequency drives) on pumps and blowers
There are many ways to reduce a ship’s energy consumption, one of which is with the use of variable frequency drives. Variable frequency drives have a low investment cost and are easy to install, even when the ship is travelling.
3-D Printing Technology
Further developments in this process can lead the industry to use this technique to build complex geometries of ship like bulbous bow easily. The prospect of using 3-D printers to seek quick replacement of ship’s part for repairing purpose is also another interesting concept.
Shipbuilding Robotics
Recent trends suggest that the shipbuilding industry is recognizing robotics as a driver of efficiency along with a method to prevent workers from doing dangerous tasks such as welding. The shortage of skilled labour is also one of the reasons to look upon robotics. Robots can carry out welding, blasting, painting, heavy lifting and other tasks in shipyards.
Buckypaper
Comparing with the conventional shipbuilding material (i.e. steel), buckypaper is 1/10th the weight of steel but potentially 500 times stronger in strength and 2 times harder than diamond when its sheets are compiled to form a composite. The vessel built from this lighter material would require less fuel, hence increasing energy efficiency. It is corrosion resistant and flame retardant which could prevent fire on ships.
Dr. Nikitas Nikitakos is a Professor in the Dept. of Shipping Trade and Transport, University of the Aegean