Green Ship Technologies

Programme Topics:

LNG as fuel for ships

With increasing demand for environmental protection and improvements in marine vessel operations, the International Maritime Organization (IMO) has adopted the Energy Efficiency Design Index (EEDI) for the control of emissions of nitrogen oxide (NOx) and sulphur oxide (SOx), as well as carbon dioxide (CO2) per ton mile.

The global shipping industry faces a challenge as new legislation will significantly limit sulphur emissions from ships. LNG is a potential solution for meeting these requirements – it has virtually no sulphur content, and its combustion produces low NOx compared to fuel oil and marine diesel oil. LNG is not only cleaner-burning but may have economic advantages – on a calorific value basis. Even high Asian LNG prices are lower than global bunker fuel prices. As a result, there have been recent developments to promote use of LNG as a bunker fuel.

LNG as a bunker fuel faces a number of challenges; notably the investment required in ships propulsion and fuel handling systems and in bunkering facilities, plus development of new international safety regulations, and LNG availability. This course will discuss the advantages of LNG as a bunker fuel, challenges faced for widespread implementation, and the pace and potential for LNG to displace established fuels, and provide an overview of about the current developments in the field of gas as ship fuel with special focus on the components of a gas-fuelled propulsion system.

Followings are the focus points of the Course:

Properties of liquefied gases, Applicable rules and regulations, Tank and pipe systems and ventilation, LNG fuel transfer operation, Types of bunkering technologies and their operations, Safety-related aspects of a gas-fuelled propulsion system, Principle of LNG and DF engine operation, Ship type considerations and Fire prevention, and emergency operations.

Waste Heat Recovery System

Waste heat is used to produce steam or electricity which is consumed on board. As main engines’ thermal efficiencies start to plateau because they are close to the theoretical maximum efficiencies and as emission regulation becomes more stringent, it is important to look for alternative usages, processes, and designs of waste heat recovery systems.

The purpose of this course is to give a broad idea of how energy on board a ship can be re-utilized in order to decrease the ship’s fuel consumption, hence reducing the emission of noxious gases into the environment. Also, it explores traditional and alternative waste heat recovery processes, usages, and systems, which are installed on board nowadays or could be in the near future. This work focuses mainly on the use of the ship’s prime mover waste heat.

A vessel installed with Waste Heat Energy Recovery System would have more than 5% reduction in fuel consumption. The waste heat energy recovery system is one of the steps taken toward future marine engines in the next-generation vessels. The course will further encompass how the system recovers waste heat energy of the main engine and uses it to generate electricity with a hybrid supercharger equipped to generate power, and a turbo generator, which is combined with steam turbine. The electricity generated not only meets onboard power demands but also assists the ship’s propulsion via the shaft motor fitted to the crankshaft of main engine. This reduces fuel consumption of both the power generator and the main engine, which contributes to a reduction in emissions as well.

Improved Pump and Cooling Water system

With stricter environmental policies, rising energy costs, a struggling global economy and the threat of climate change, there has been a revival in the focus on efficiency improvement in the pump and cooling water system.

Energy efficiency of a ship requires both efficient production and efficient use of the energy onboard. The most important decisions regarding ship energy efficiency are made at the early concept design phase, when the choices regarding the ship capacity, main dimensions and the basic machinery and fuel for the ship are made. After these decisions, the improvement potential lies in subsystem optimisation onboard.

Cooling systems are one of the larger energy consumers on board a vessel. Studies show that it is possible to save the energy required to run the pumps by optimizing the system and using frequency-controlled pumps. Green Ship of the Future (GSF) members have developed decision packages, with possible improvements to cooling systems efficiency, both for retrofitting and new ships.

By using an optimised cooling water system it is possible to save up to 20% of the electrical generated power, corresponding to approximately 1.5% reduction of the total fuel consumption. Studies show that the resistance in the cooling water system often can be reduced. An optimised cooling water system of pipes, coolers and pumps can result in decreased resistance to the flow. This will lead to savings of electric power of the ship and fuel consumption.

The course will cover the following:

Central Cooling System, Correct cooling for low energy consumption, Energy efficiency solutions, Variable Speed Drives vs. Manual Control, Alternatives for the efficient LT-water cooling system, Over-dimensioned and under-utilised system and an Energy efficiency project.

Energy efficiency and Management

A new rule for the implementation of the energy efficiency is underway by the global watchdog for the maritime industry, the International Maritime Organization (IMO). The stakeholders over whom the regulation will have a direct impact over are the shipowners and operators who have already expressed great concern over what is called the Energy Efficiency design Index (EEDI).

In terms of CO2 emissions per ton of cargo, shipping is the most efficient form of commercial transport. But due to the sheer scale of the industry, shipping contributes to about 3% of the world’s emissions.

The Ship Energy Efficiency Management Plan (SEEMP) is an operational measure that establishes a mechanism to improve the energy efficiency of a ship in a cost-effective manner. The SEEMP also provides an approach for shipping companies to manage ship and fleet efficiency performance over time using, for example, the Energy Efficiency Operational Indicator (EEOI) as a monitoring tool. The guidance on the development of the SEEMP for new and existing ships incorporates best practices for fuel efficient ship operation. The EEOI enables operators to measure the fuel efficiency of a ship in operation and to gauge the effect of any changes in operation, e.g. improved voyage planning or more frequent propeller cleaning, or introduction of technical measures such as waste heat recovery systems or a new propeller.

The Course covers the following:

Climate change and Shipping, Shipboard energy management, Port operations management, Fleet operation management and Energy policy and management.

Speed Nozzle

In large merchant vessels, conventional open propellers either with a fixed or a controllable pitch, are used and the maximum efficiency of the propeller is reached by using the largest possible diameter and optimizing the propeller shape when the nominal wake field of the ship is known. The efficiency of the open propeller behind the hull can be in some situations further improved by different flow stabilizing devices, such as pre-swirl stators and ducts positioned upstream of the propeller. These devices are intended for creating a more uniform inflow to the propeller and in this way improving the propeller efficiency.

In an accelerating nozzle which is the normally used type of nozzle, the water speed at the propeller disk is higher than that of the open propeller. For accelerating nozzles, the increase in axial velocity reduces the propeller load especially for heavily loaded propellers. This then leads to an increase in overall performance of the propeller and nozzle compared to that of a propeller alone.

In recent years, considerable efforts have been made in order to improve the propulsive efficiency of the propeller on the ships. The marine speed nozzle which is positioned around the propeller of a ship, is hydrodynamically structured so that it maximizes the thrust provided by the propeller at lowers speeds, while also increasing the free running speed of the vessel.

The course covers the following:

Concept of propeller in nozzle / ducted propeller, Working principle of marine nozzle, Operational analysis of speed nozzle, Application of aerodynamics in ship propulsion, Ducted propeller by momentum theory and Performance of speed nozzle.

Sandwich Plate system

Modern sandwich plate system (SPS) evolved through 10 years of development since it was presented as a new material for the application in offshore structures subjected to heavy seas and ice in Canadian Beaufort Sea. It is used in military, offshore, maritime, civil engineering etc. SPS was patented by the company named Intelligent Engineering (IE), recognized as a dominant producer of sandwich constructions, particularly in ship repair.

Sandwich plate system eliminates the need for secondary stiffeners, making the structure less complex and flush. Considering the high strength to weight ratio, ease of construction, blast and ballistic properties of the material, availability of a flush surface etc., SPS has been widely used in building bridges, stadiums, floors, blast walls etc. SPS panels have also been used in ship repair as an overlay on existing structures, converting them conventional steel to sandwich plates. The concept of complete hull structure made of SPS is a big challenge. The introduction of Class rules has brought in the use of sandwich structures in marine construction. It is roughly estimated that weight reduction possibilities of SPS over the conventional structure varies from 10 to 70%. The scope for SPS panels in shipbuilding, offshore structure and various areas where further research and progress could be made is also recommended.

The Course covers the following:

Short history of SPS, Terminology, Core materials, Adhesive materials, Honeycomb cores, Advantages of SPS panels, SPS in shipbuilding, SPS in ship repair, Design principles.

Ballast Free Ship Design

Currently, under the recently adopted IMO ballast water Convention, the main management practice available to ships to reduce the transfer of harm-full aquatic organisms in ballast water and sediments, is for the ship to exchange its ballast water in the open ocean during the voyage. The Convention therefore sets performance criteria and phase-in deadlines for new and improved ballast water treatment systems.

The potential techniques for treating ballast water that are currently being investigated include filtration, heat, ultra-violet light, ozone, de-oxygenation, electro ionisation and chemical biocides, among others.

However, all of these technologies are currently experimental and developmental only, and none have yet been shown to be fully effective in a full-scale shipboard application. The operational, engineering, economic, biological and even cultural barriers to their wide-spread adoption and successful operation, require more creative and tangential thinking to develop much simpler, more complete solutions.

One question that’s why often asked is “Why not just eliminate the use of ballast water?” The essence is to find a solution to the problem of the contamination and deterioration of the environment; especially the salt water that is being carried from A to B causing this problem. To stop this problem the goal is to create a ballast-free vessel.

The Course covers the following:

Concept of a ship without ballast water, Design concepts, Advantages and disadvantages of various design concepts, Hydrodynamics and Automation system.

Solar and Wind Powered Ships

The vast majority of ships are dependent on fossil fuels that burden the environment. Alternative energy is on the rise in the marine world, and ships powered with renewable energy are prepared to sail into a much cleaner future. One of these options is to tap wind and solar power and use the same for generating energy.

In addition, solar panel technology has now reached a point where it is becoming more practical and cost effective to include solar power solutions on vessels and in some cases, it is possible to collect wind and solar power via the same device or system.

Recent advances in solar cell and photovoltaic module technologies have led to solar power becoming a cost-effective fuel reduction option. Using solar power, the fuel consumption on-board ships can also be controlled. Bigger vessels can save 1000 tons of fuel and cut CO2 emissions by 3000 tons annually by using renewable energy.

Ship owners, ship managers, shipyards and vessel operators are increasingly looking to incorporate marine renewable energy & hybrid marine power technologies into the mix of propulsion & power systems for their vessels. Not only do these technologies reduce noxious gas emissions but they also reduce fuel consumption and deliver cost savings to vessel operators and/or owners.

The Course covers the following:

Use of renewable energy for greener shipping, Design concept of wind propelled ship, Solar Power System concept on ship, Advantages and benefits of solar and wind powered ships, Harnessing Wind & Solar power concept and Hybrid marine power & propulsion systems.

Fuel Cell Propulsion

Fuel cell power systems have attracted attention because of their potential for high efficiency, low emissions, flexible use of fuels and quietness. Application of fuel cell technology to the transportation field in general and to the marine transportation field is still in the early exploratory stage.

Fuel cells, like a battery, produce energy from an electro-chemical process rather than combustion. Fuel cells have no moving parts but do require additional support plant such as pumps, fans and humidifiers. Two reactants, typically hydrogen and oxygen, combine within the fuel cell to produce water, releasing both electrical energy and some thermal energy in the process. Unlike a conventional battery in which the reactants consumed in the energy conversion process are stored internally and eventually depleted, the reactants consumed by the fuel cell are stored externally and are supplied to the fuel cell in an analogous way to a conventional diesel engine. Hence a fuel cell has the potential to produce power as long as it has a supply of reactants.

Just like batteries, fuel cells are modular in nature and the intrinsic performance of a single cell is not different from a large stack. As a result, power production can be distributed over the ship without a penalty of increased fuel consumption, while electricity transport losses are reduced and redundancy is improved. For this reason, fuel cell systems are successfully applied in back-up power systems and data centers.

The Course covers the following:

Fuel cell technology, Types of fuel cells design, Fuel cell technical requirements for ships, Fuel cell systems for ships and Fuel cells for ship application.