THE ELECTRIC PROPULSION SYSTEMS

Presented By : Mohamed Gamal Hussien & Ahmed

Yasser Soliman

Under the supervision of :

Prof. Dr. Adel Tawfik

1 • Overview of The Conventional Power Plants in Marine System.

2 • The Electric Propulsion System .

3 • Types of Electric Propulsion System .

4 • Electric propulsion system components .

5• The Advantages and the

Disadvantages of the Electric Propulsion

6 • Case Study.

7 • Future Trends of Power Electronics and Drives .

8 • Conclusion

Tableof

Contents

OVERVIEW OF THE CONVENTIONAL

POWER PLANTS IN MARINE SYSTEM :

CHAPTER (1) :

Selection of marine power plantsystem

1. Reliability.

2. Machinery space and arrangement

3. Machinery weight and volume requirements

4. Type of fuel and fuel consumption

5. Machinery costs .

6. Interrelations with auxiliaries

7. Maintainability

8. Vibration and noise .

9. Reversing capability .

10. Operating personal .

Classification of Conventional Marine Power Plants

Diesel Engine Power PlantSteam turbine power plantGas turbine power plantNuclear power plantCombined power plants

Diesel Engine Power Plant

The Main demerits of marine diesel engines in

conventional system

1. The DE is slightly greater weight compare to the gas turbine

for the same power .

2. The high speed DE provides high fraction losses in operation

particularly at partial loads .

3. The DE has a high fuel consumption at partial load .

4. The high and medium speed engine must coupled to a GEAR

BOX .

Fuel consumption of the DE :The efficiency drops fast as the load becomes lower than 50% of MCR. At this working condition, the combustion is inefficient, with high NOx and SOx content , and with a high degree of soothing which increases the need for maintenance .

Snaky Diagram of the DE

Steam turbine power plant

The Disadvantages Of Steam Power Plant : 1. Fuel consumption is considerably higher than the diesel engine .

2. Low Efficiency engine compared to Diesel Engine .

4. Capital cost of the Steam power plant is high .

3. Turbines must run at high speed for best efficiency so a high ratio

reduction gear is essential to obtain an economical propeller speed .

Efficiency of the steam power plant :

Emissions of the Steam Power Plant :

Gas turbine power plant

The Disadvantages of Gas Turbine system .

1- The Gas Turbine has high fuel consumption .2- It needs a big reduction gear and reversing

mechanism . 3- It requires large area and space for the

inlet air system .

Nuclear power plants

The Disadvantages Of The Nuclear Power Plant are :1. Reactor plants are heavy

and require very dense shielding to contain radiation .

2. The high capital costs of installation , operation and maintenance .

Combined power plants

Disadvantage :1- Their complexity .

2- Occupying large machinery space .3- Higher first and installation cost .

The First cost of the combined power plants compared to Diesel power plant :

THE ELECTRIC PROPULSION SYSTEM

CHAPTER (2):

History Of Electric Propulsion… more than 170 years 1839: a small Russian ferry was built which was propelled by an electric motor fed by a storage battery.

In 1903 / 1904 , diesel engines were reliable enough to be used as ship propulsion but they were still non-reversible. At that time,

electric power transmission therefore was the only method to overcome this basic technical problem.After the rather experimental applications of battery driven electric propulsion at the end of the 19th century took place in Russia and Germany…

• As a result of the strong competence of reducing transatlantic crossing times for passenger liners.

• the high propulsion power demand could only be achieved by turbo-electric machinery.

First generation of electric propulsion 1920’S

Steam turbine generators provided electric power that was used to drive the 29MW synchronous electrical motors on each of the four screw shafts.

Second generation of electric propulsion 1980’S• In the middle of the 20th century ,diesel engines appeared with :1- High efficiency.2- Economical value.Therefore, steam turbine technology and electric propulsion disappeared from merchant marine vessels.

• The development of variable speed electric drives: • First by the AC/DC rectifier in the 1970’s .• Second by the AC/DC converters in the early 1980’s.• These solutions were firstly used in special vessels like survey

ships and icebreakers, but also in cruise vessels. • “S/S Queen Elizabeth II” was converted to electric propulsion in

the mid 1980’s.

Breakthrough for Electric Propulsion 1990’S• Podded propulsion was introduced in early 1990’s where the

electric motor is installed directly on the FPP shaft in a submerged, rotatable pod.

• Enhance the performance of icebreakers, it benefits on hydrodynamic efficiency and maneuverability.

• After the fist application in a cruise liner, “M/S Elation”, podded propulsion became a standard on new cruise liners.

The market for electrical propulsion will grow significantly

2003

04050607080910111213141516171819200

1000

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3000

4000

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0 %

5 %

10 %

15 %

20 %

25 %

Ordered vessels over 2000GT by vessel number, (ABB Es-timate)

Share of vessels with electrical propulsion, % (ABB Es-timate)

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#

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Electric propulsion has become the technology of choice for several vessel segments due to the fuel efficiency and low emissions.

Electric propulsion will become as the solution for new merchant vessel segments, e.g.: container, dry cargo vessels.

Electrical propulsion vessels are projected to represent 20% of vessel numbers in 2020.

CHAPTER (3) :

TYPES OF ELECTRIC PROPULSION SYSTEM

Types of electric propulsion system

1- DIESEL ELECTRIC MACHINERY SYSTEM .

2- CODED “COMBINED DIESEL-ELECTRIC AND DIESEL-

MECHANICAL

MACHINERY ” .

3- DUAL FUEL ELECTRIC PROPULSION .

4- CODLAG ” COMBINED DIESEL-ELECTRIC AND GAS

MACHINARY ” .

5- COGES “ COMBINED-CYCLE GAS AND STEAM TURBINE

ELECTRIC

MACHINERY ” .

1- Diesel-electric propulsion systemBy using diesel electric propulsion, we will able to operate diesel

engines at :1- Raise the overall efficiency. 2- Reducing emissions. 3- Making the ship greener.

A medium speed diesel engine has a low fuel consumption at the optimum operation

point.

2- CODED propulsion system1- The first cost and Transmission losses is lower than for diesel-electric system machinery .

2- CODED can improve the total efficiency in ships with an operational profile containing modes with varying loads.

3- Dual fuel electric propulsion Most of regulations focus on NOX and SOX emissions that for

the most part, have a local impact on the environment.

The only ways for ships to reduce their CO2 emissions are either to reduce fuel consumption is natural gas.

Switching from HFO to natural gas will significantly reduce all important exhaust gas emissions from a ship, including a 30% reduction in CO2 emissions .

4- CODLAG:This means that there is at least one diesel engine and one gas turbine driving generators to create electric power for both the propulsion and the hotel side.The CODLAG concept was to be able to operate without any smoke formation in special areas such as Alaska.

Gas turbines are directly connected to the alternators. Heat-recovery boilers are fitted in the gas turbine exhaust lines and the resulting superheated steam (at approximately 30bar) is led to a steam turbo alternator .This solution changes completely the properties of a simple-cycle turbine; whereas gas turbine efficiency decrease at low load, the steam turbine recovers the lost power.

5- COGES:

Heat for ship’s services is taken directly from the steam turbine exhaust (back-pressure turbine), and thus there is normally no need to fire-up auxiliary boilers.

General comparison :

Total fuel cost COGES HIGHER THAN CODLAG & DIESEL-ELECTRIC

Weight of the machinery

CODLAG LOWER THAN DIESEL-ELECTRIC

The space needed COGES SMALLER THAN DIESEL-ELECTRIC

All these systems have the advantages of electric propulsion but with different values

The CODED machinery is better than diesel-electric machinery combines the benefitsReduce : The first cost The fuel consumption.

Compare between dual fuel electric machinery and other systems Offers significantly lower emission levels

Electric propulsion system components

CHAPTER (4):

How can the System work ?

Electric propulsion system components:

ELECTRIC POWER GENERATION

Prime mover.Generators.

Energy storage system.

ELECTRIC POWER GENERATION:1- The prime mover :The function of the prime mover is to deliver mechanical energy which will be converted into electrical energy.

• May be one of the following: Diesel engine Gas turbine Steam turbine Combined cycles

2- Generators :A device that converts mechanical energy obtained from prime mover into electrical energy. Wound rotor synchronous generator.Permanent magnet synchronous generator.

3- Energy storage system: BatteriesSuper capacitors

ELECTRIC POWER DISTRIBUTION:

ELECTRIC POWER CONSUMPTION:The electrical motor is the most commonly used device for conversion from electrical to mechanical power and is used for electric propulsion.

1- Electric propulsion motors

Induction motors.

Synchronous motors.

Permanent magnet motors.

High temp. superconductor

motors.

2- Propulsion units

Shaft propulsion Azimuth thrusters

Podded Propulsion

• Podded Propulsion benefits :1- Increases the hydrodynamic efficiency of the propeller.2- Reduces the risk for cavitation.3- Reduced noise and vibrations.

Podded propulsion units have been in operation in a decade in cruise vessels, icebreakers, service vessels and tankers.

CHAPTER (5) :

The Advantages and the Disadvantages of the Electric

Propulsion

THE ADVANTAGES OF THE ELECTRIC PROPULSION SYSTEM :

Flexibility of layoutIt is estimated that a reduction of about 30% volume is possible compared to the conventional mechanical drive system

Load diversityThere are advantages in having a single central power generation facility which can service the propulsion and all other ship loads as

required.

Fuel savings For ships spending more time at low speed, fewer engines can run at full power, resulting in greater energy efficiency and hence less fuel consumption.The navy ship with IEP may save an estimated 15–25% in fuel compared to a similar ship with mechanical drive. The lifetime cost saving from reduced fuel consumption may exceed the higher initial procurement cost of electrical propulsion .

The Norwegian Epic cruise ship

It has a beneficial impact on the environment from reducing fuel consumption by 14,000 tons per year .

Greater maneuverabilityThe use of podded propulsion can permit a tighter turning radius and give an

ability to change the direction or orientation of the ship even at very low

speeds Moreover, the speed and direction of the prime mover need not be

changed to affect the speed, direction, and rotation of the propeller For

icebreakers, ferries, tugboats, oceanographic

vessels , and cable-laying ships that require

frequent speed changes and direction

reversals, electric propulsion offers a great

advantage over mechanical propulsion .

Low noiseAn electric motor is able to provide a drive with very low vibration characteristics and this is of importance in warships, oceanographic survey vessels and cruise ships where, for different reasons, a low noise signature is required .

Higher automation The electric propulsion system can be designed to be highly automated and self-monitoring , hence requiring less maintenance and fewer crew members to operate than with a mechanical drive system.

Best Complementation with the propeller

Economical part-load runningPart-load in a conventional system .

Part-load in an electrical system .

Low Emissions

Disadvantages of System

Lower overall energy efficiency for ships running at full-rated speed all the time due to losses

Higher initial capital cost

Different and improved training for ship’s crew as the system is completely different from mechanical system and involves major automation.

Losses

Component Fuel ( 100 % )

53 % Prime mover 47 %

4 % Generation 45.12 %

1 % Distribution 44.67 %

1 % Transformers

44.22 %

4 % Propulsion convertor 42.45 %

4 % Propulsion Motor 40.75 %

lower overall energy efficiency for ships running at full-rated speed all the time due to losses

Losses

Component Fuel ( 100 % )

43.6 %Variable speed Prime

mover Estimated 20 %

improvement in efficiency

56.9 %

4 % HTS generation 54.14 %

0.77 % DC Distribution estimated 23 % reduction

in losses

53.72 %

3.16 %Use silicon- carbide

Propulsion convertor estimated 21 % reduction

in losses

52.02 %

4 % HTS Propulsion Motor 49.94 %

The solutio

ns :

MISC Berhad

Mitsubishi Heavy Industries, Ltd. (MHI) has designed and constructed an electric propulsion carrier for MISC Berhad that makes use of dual-fuel diesel engines. This paper describes our dual-fuel diesel–electric propulsion LNG carrier, which is the first ship of its kind constructed in Japan.

The measured fuel oil

consumption rate (FOCR) of this

carrier during its sea trial and

FOCR of an identical horsepower

steam-turbine propulsion plant

are shown in Figure . The

propeller shaft horsepower

FOCR indicated approximately

20% energy savings compared

to the steam-turbine propulsion

plant .

Future Trends of Power Electronics and Drives

CHAPTER (6) :

Quick Charging Plug-in Electric Boat “ RAICHO-I ”

Main Specification of the boat :

-18[ kWh ] lithiumion battery of which

w eight is about400 ] [ kg- 80 % of full charge of the battery

can be recharged by the quick charger within

- 30[ min] -The operational time with the

full charged battery is about 45 [min].

-the motor power is about 25 [kW] .- The maximum speed of “RAICHO-I” is

about 10 [knots] with half load and 8.5

[knots] with full load. Full load means 2

crews and 10 passengers on board.

The world's first electrical ferry “ AMBER ”

Length 80 mWide 20 mElectric motor 2 each with 450 KW output

Material Aluminum .Batteries 10 tonPassengers about 360vehicles about 120ferry travels 6 Km across the fjord 34 times a day,

with each trip taking around 20 minutes.

The Norled ferry will consume around two million kWh per year, whereas a traditional diesel ferry

consumes at least one million liters of diesel a year and emits 570 tons of CO2 and 15 metric tons of NOx

Reduces cost of fuel by 60 percent

Ferry only uses 150 kilowatt hours (kWh) per route

Batteries

lithium-ion batteries which are charged from hydro power.

The 260-kWh-units supply electricity to the ferry while it waits.

More efficient and less expensive in the next few years, which tip the scales further away from diesel as the most popular fuel source.

Developed by Siemens and Norwegian shipyard Fjellstrand, the vessel can recharge its batteries in just ten minutes.

ADVANTAGES OF All-ELECTRIC

SYSTEM :

1- Zero emission of NOx, SOx and CO2

when running .

2- Low noise and vibration .

3- No smell of exhaust gas .

4- 50 – 70 % of CO2 can be reduced by

electric boats

compared with conventional boats.

Conclusion:Using Electric Propulsion System means :

1- Increase space for payload.2- Less maintenance of generator sets.

3- Improve dynamic response and

maneuverability.

4- Up to 25 % fuel saving.

5- Low emissions.

Any