marine propulsion history and electric propulsion & future technology

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Mohd. Hanif Dewan, Chief Engineer and Maritime Lecturer & Trainer, Bangladesh. Marine Propulsion History And Electric Propulsion & Future Technology 1

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"Marine Propulsion History and Electric Propulsion & Future Technology"

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Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh.

Marine Propulsion History

And

Electric Propulsion &

Future Technology

1

40,000 years before christ, man built boats and paddled through the waters with them. And, they paddled and paddled and paddled for 35,000 years until a major discovery revolutionised ship propulsion for the first time.

History of Marine Propulsion

5/17/2014 2 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Mankind paddled round for 35,000 years – just like the indians – and then they began using oars –similar to the tourists on the alster lake. Then mankind oared round for several thousand years – namely, up to 3,000 b.c. until the sail was discovered, supposedly in Egypt. finally, more than just the nile and the coastal regions of the Red and Mediterranean seas could be explored. the seafarers could then set off on voyages crossing the seas and circling the continents. For a long time, the seaman couldn’t give up using the oar and combined the oar with the sail.

History of Marine Propulsion

5/17/2014 3 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The ships got bigger and bigger, Hamurabi lived and died, and, finally, the oars were completely done away with. And, in this manner, mankind sailed almost 5,000 years – until the year 1770 A.D.

Roman warship with sail and oars – around 200 B.C.

History of Marine Propulsion

5/17/2014 4 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

when James Watt, further developed the steam engine so that it, a short time thereafter, could be built into a ship.

History of Marine Propulsion

Cross-section and full-view of a 2-stage steam engine 5/17/2014 5

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

At this period in time, the propeller had not yet been invented and, what was more convenient to make use of than the old-familiar paddle-wheel of the flour and lum- ber mills. The paddle-wheel propelled the ship, and the steam engine drove the paddle-wheel. The coal-fired boilers provided the steam for the steam engine.

5/17/2014 6 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

“Contemporary” depiction of propulsion (steam engine and paddle-wheel) of the steamboat "Claremont"

5/17/2014 7 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

There were certainly attempts at in- terim solutions. This illustration is not a comic drawing but rather the then contemporary depiction of a submarine propelled by muscle power, which sank the "Housatonic" in 1864.

Submarine "H.L. Hunley" on 17.02.1864 while attacking the "Housatonic"

5/17/2014 8 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Mankind didn’t throw the sail overboard and install a steam engine, rather one slowly felt his way forward – the ships had a sail and a steam engine and a paddle-wheel (later a propeller, as well).

Steamship "Great Eastern" around 1860. The ship had 6 masts, 2 paddle-wheels and a four-bladed propeller 5/17/2014 9

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Steamship "Helena Sloman" around 1850. The ship had a full set of sails and a propeller

5/17/2014 10 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Then, 60 years later, in the year 1827, Joseph Ressel had the ship propeller patented. He was an Austrian and had the exciting title of a “Marineforstintendant”. The iron propeller was a great improvement as compared with the wooden paddle-wheel with its many fragile pieces. The propeller was able to be adapted to all of the following types of propulsion and output standards of today.

5/17/2014 11 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Depictions of a paddle-wheel and a “prototype” of a propellerr

5/17/2014 12 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Meanwhile, propellers are built which can manage 120,000 hp and weigh over 130 tonnes having a diameter of just short of 10 metres. Here, the limit of possibility certainly seems to have been reached.

5-bladed control pitch propeller for a container 5/17/2014 13

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Let’s take just another look back into the century before the last, in which the steam engine set about replacing the sail. The demands made on output got bigger and bigger; the steam engines, as well. The performance limit of 20,000 hp per steam engine was quickly reached. So, several steam engines had to be built into a ship in addition to numerous boilers – sometimes 15 or more. Besides that, many hundreds of tonnes of coal had to be brought on board and stored.

5/17/2014 14 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

One of the two steam engines of the steamship

"Kronprinzessin Cecilie" (1907), 22.000 hpi

5/17/2014 15 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Around 1900, the first steam turbines were built into ships. While having a larger output, they required much less space than steam engines, but the old steam boilers remained on board, and they were still fired manually with coal.

Cross-section of a high-pressure stage of a modern steam turbine 5/17/2014 16

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The amount of effort required to fire the boilers with coal is no longer imaginable today! One needed the coal heaver, who transported the coal from the storage room – from the coal bunker – up to just in front of the boiler; one needed the stoker, who shovelled the coal into the boilers and maintained the steam pressure; one needed the many helpers, who transported the ash from the boiler overboard. And, all of that for each individual boiler and for each of the three shifts.

View of the boiler room of a coal-fired steam boiler system 5/17/2014 17

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Around 1920, when the Hamburg-Süd steamship "Cap Polonio" was refitted from coal-firing to oil-firing, the boiler room personnel was able to be reduced by just 110 men.

View of the furnace of two oil-fired steam boiler systems 5/17/2014 18

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

With the steam turbines, finally the industry had ship propulsion systems with - for ship standards – huge performance reserves available (today, stationary steam turbine systems are built with over 1.5 million horsepower per turbine). The oil-fired boilers were also quite comfortable. But, in this case, fuel consumption was very high. The efficiency of a steam turbine was, in comparison with a steam engine, from which only 10 to 20% of the energy used made it to the propeller, considerably better – but still left loads of room for improvement having only 25 or 30% efficiency. So, in regard to ship propulsion, the steam engine and the steam turbine only had a relatively short “cameo-appearance” in the greater scheme of things.

5/17/2014 19 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

In the year 1876, thus 130 years ago – the combustion engine was invented by Nikolaus Otto. It had to be driven with benzine, which at the time had to be purchased at the chemist’s with high prices. The combustion engine was, thus, discovered, but it wasn’t originally good for ship propulsion because it used too much expensive petrol. Even 50 years before the invention of the Otto motor, the Frenchman, Carnot, described a thermo-dynamic cyclic process with theoretically the highest possible degree of efficiency.

5/17/2014 20 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

With the above in mind, Rudolf Diesel developed a combustion engine which operated according to the Carnot-principle and had the same patented in 1892. The 'diesel engine' reached a spectacularly high efficiency of 20, then 30, then 40 and finally 45 %. Around 1910, one began to build diesel motors into ships as the main source of propulsion. The entire diesel engine took up approx. as much as three boilers and, thereby, replaced a steam propulsion system, which perhaps was comprised of 2 turbines, 15 boilers and countless auxiliary units and, thereby, required 30 % less fuel. From 1910 to today, the diesel engine has gone through an unparalleled technical develop-ment. Similar to the propeller, the diesel engine was able to be adapted to every demand on size and output performance. 5/17/2014 21

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Left: View of a large two-stroke diesel engine around 1912 (1,500 hp at 120 RPM)

Right: Embedding of a crankshaft in a 12,000 hp 6-cylinder MAN two-stroke engine

5/17/2014 22 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Ship diesel engines of today are available in every size and output class up to 135,000 hp. They are extremely reliable, and the so- called specific fuel consumption is unbeatably low with 119 grams per hp and hour (g/hph) – at its time, the steam engine consumed approx. 700 g/hph. In addition, the 'combined heat and power' principle, which is talked about so often today, has been common practice in ships with diesel propulsion for ages. Heat is detracted from the diesel engine’s exhaust gases, which, in spite of everything else, still contain about 50 % of the thermal energy used, by connected turbo chargers and steam boilers so that the efficiency of the entire system rises to over 70 %.

5/17/2014 23 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Cross-section of a MAN-B&W ship diesel engine 6S 70 ME-C (25.000 kW @ 91 RPM , weight - 550 t, height – 14 m)

The diesel engine has many advantages. It has displaced every other type of propulsion in shipping. Today, approx. 90% of all merchant vessels are propelled by diesel engines, world-wide.

5/17/2014 24 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

However, the times of rapid technical developments in the ship diesel engine are gone – which, for one, lies in the fact that the highest possible degree of efficiency has almost been reached, and, for another, that now possible output of 150,000 hp can no longer be surmounted by one single propeller. There is no longer any reason to boost the output of any one single ship diesel engine. In case it’s necessary – now, two engines would have to power two propellers - and then there would be 300,000 hp of installed propulsion output. The size of merchant vessels which would require such an amount of output are not imaginable today, and such vessels won’t be playing a roll in shipping in the intermediate-term.

5/17/2014 25 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The diesel engine has almost displaced every other type of propulsion and is absolutely market dominating. It displaced the steam turbine, which today only plays a secondary role in regard to ship pro- pulsion. It displaced the nuclear powered merchant vessels which were built in the 60’s of the previous century – namely, the Savannah (USA), the Otto Hahn (Germany) and the Mutsu (Japan). NS "Otto Hahn" - 1965

5/17/2014 26 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

All three ships were powered by propellers, which, in turn, were driven by steam turbines typical of merchant ships – only that the steam was not produced in oil-fired boilers but rather in a so called pressurised-water reactor. The ships were extremely expensive and uneconomical, and at their time they were only able to touch at very few ports worldwide owing to a lacking acceptance in the population. They also required a large number of well-trained crew members. The "Otto Hahn" had e.g. a regular crew of nearly 60 men plus 35 scientists on board.

View of the pressurised-water reactor of the NS "Otto Hahn"

5/17/2014 27 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The diesel engine also displaced ships with gas turbine propulsion. These ships had airplane jet engines, which functioned as so-called gas generators which, in turn, powered turbines. The latter rotated similar to a steam turbine and powered our old-familiar propeller.

Pratt & Whitney gas turbine FT 4 A12 (30.000 Ps) of the GTS "Asia Liner" 5/17/2014 28

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Even this type of propulsion was extremely uneconomical in that it, for one, required the same top-quality, expensive fuel as that of an airplane jet engine and on top of that, it had an effi- ciency of only 21 % which was – at least in comparison to that of a diesel engine – awfully low. Every ship with gas turbine propulsion known to me was converted to diesel engine propulsion after a few years. In the table below, we can compare the degrees of efficiency and specific fuel consumption of the various types of propulsion. The specific fuel consumption is, by the way, the amount of fuel that the system must be given in order to produce 1 hp for one hour (g/hph). we see that the modern Engine Makers have worked down from 700 g/hph to 120 g/hph today. 5/17/2014 29

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Comparison of the thermal degrees of efficiency and specific fuel consumption

efficiency specific fuel consumption

sail ./. 0

steam engine 10 – 15 % 700 g/hph

gas turbine 21 % 320 g/hph

steam turbine 30 % 220 g/hph

diesel engine 45 % 120 g/hph

hydrogen 30 % ./.

5/17/2014 30 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The ship propulsion must be reliable and, above all, economical. Diesel propulsion satisfies both requirements thoroughly and without any competition – at least as long as heavy fuel or diesel oil or, as the case may be, liquid gas (LNG) is readily available and affordable. Beginning in 2070, oil appears – in comparison to today – to play a rather inferior role. In other words, there is little to be said against the diesel engine’s maintaining its dominating role in the market at least until 2030. the SKYSAIL or the FLETTNER-ROTOR don’t really help us out of the predicament, either. Our ships need propulsion independent of the weather and with enormously large output. "Auxiliary propulsion units" cannot manage this by far. 5/17/2014 31

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

SkySail – only suitable for „auxiliary propulsion“

5/17/2014 32 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Flettner-Rotors – only suitable for „auxiliary propulsion“

5/17/2014 33 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Special ships such as submarines – is hydrogen propulsion. The term "hydrogen propulsion" is just as misleading as "nuclear propulsion". A ship with hydrogen propulsion is still powered by the propeller and the latter by an electric motor. Both components are old friends – the propeller, anyhow, and the electric motor has already been implemented in the so-called diesel- electric propulsion for many years. Thereby, a diesel engine powers an electric generator of which energy goes to an electric motor, which, in turn, powers the propeller. The last step of this development is the so called 'AZIPOD', which contains the electric motor directly in the pod (gondola) behind the propeller.

5/17/2014 34 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

“Electric 'Azipod' propulsion” Left: View of the 'gondolas' with drag-propeller Right: Schematic diagram with view of the mounted electric engine in the 'gondola'

5/17/2014 35 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

In regard to hydrogen propulsion, we can manage without a diesel engine and a generator as we produce the energy for the electric engine e.g. from the fusion of hydrogen and oxygen, whereby water and heat are generated so to speak as by-products – in addition to the energy, itself. In Hamburg, some buses are already powered by hydrogen cells, and THYSSEN KRUPP has been successfully building submarines using this technology.

5/17/2014 36 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Left: Functional principle of a hydrogen cell

Right: Technical layout of a hydrogen cell for submarines

5/17/2014 37 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

To introduce solar energy to the ship we need to convert the solar energy to electrical energy. electrical energy we can use and transport throughout the ship. photo-voltaic cells convert solar into electrical energy. An inverter is needed to convert the direct current (dc) to an alternating current (ac), so the 50 or 60 hz electric grid can transport the electrical energy through the ship. These energy conversions reduce the efficiency of the whole chain. With a dc grid in a diesel-electric propulsion system less energy conversions are needed, There is no need for bulky transformers.

WIND & SOLAR ENERGY FOR SHIP

5/17/2014 38 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Sail and solar power ship

5/17/2014 39 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric

Propulsion System

Marine Electric Propulsion Integrated electric propulsion (IEP) or full electric propulsion (FEP) or integrated full electric propulsion (IFEP) is an arrangement of marine propulsion systems such that gas turbines or diesel generators or both generate three phase electricity which is then used to power electric motors turning either propellers. It is a modification of the combined diesel-electric and gas propulsion system for ships which eliminates the need for clutches and reduces or eliminates the need for gearboxes by using electrical transmission rather than mechanical transmission of energy.

5/17/2014 41 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

5/17/2014 42 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion System

5/17/2014 43 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion

• Electric propulsion for many new ships is now re-established as the popular choice where the motor thrust is governed by electronic switching under computer control.

• The high power required for electric propulsion usually demands a high voltage (HV) power plant with its associated safety and testing procedures.

• Passenger ships have always been the largest commercial vessels with electric propulsion and, by their nature, the most glamorous. This should not, however, obscure the fact that a very wide variety of vessels have been, and are, built with electric propulsion.

5/17/2014 44 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion

• Early large passenger vessels employed the turboelectric system which involves the use of variable speed, and therefore variable frequency, turbo-generator sets for the supply of electric power to the propulsion motors directly coupled to the propeller shafts. Hence, the generator/motor system was acting as a speed reducing transmission system. Electric power for auxiliary ship services required the use of separate constant frequency generator sets.

• A system that has generating sets which can be used to provide power to both the propulsion system and ship. …..(cont’d)

5/17/2014 45

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

• Marine Electric Propulsion

• services has obvious advantages, but this would have to be a fixed voltage and frequency system

to satisfy the requirements of the ship service

loads. The provision of high power variable

speed drives from a fixed voltage and frequency

supply has always presented problems. Also,

when the required propulsion power was beyond

the capacity of a single d.c. motor there was the

complication of multiple motors per shaft.

…….(cont’d)

5/17/2014 46 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

A Typical Layout HV Propulsion System

5/17/2014 47 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion

• Developments in high power static converter equipment have presented a very convenient means of providing variable speed a.c. and d.c. drives at the largest ratings likely to be required in a / marine propulsion system.

• The electric propulsion of ships requires electric motors to drive the propellers and generator sets to supply the electric power. It may seem rather illogical to use electric generators, switchgear and motors between the prime-movers (e.g. diesel engines) and propeller when a gearbox or length of shaft could be all that is required.

…………..(cont’d)

5/17/2014 48 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion

• There are obviously sound reasons why, for some installations, it is possible to justify the complication of electric propulsion:

1. Flexibility of layout

2. Load diversity between ship service load and propulsion

3. Economical part-load running

4. Ease of control

5. Low noise and vibration characteristics

5/17/2014 49 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

FLEXIBILITY OF LAYOUT

•The advantage of an electric transmission is that the prime-movers, and their generators, are not constrained to have any particular relationship with the load as a cable run is a very versatile transmission medium. In a ship propulsion system it is possible to mount the diesel engines, gas turbines etc., in locations best suited for them and their associated services, so they can be remote from the propeller shaft. Diesel generator sets in containers located on the vessel main deck have been used to provide propulsion power and some other vessels have had a 10 MW generator for ship propulsion duty mounted in a block at the stern of the vessel above the ro-ro deck.

–Another example of the flexibility provided by an electric propulsion system is in a semi-submersible, with the generators on the main deck and the propulsion motors in the pontoons at the bottom of the support legs.

5/17/2014 50 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

LOAD DIVERSITY • Certain types of vessels have a requirement for substantial amounts of electric power for ship services when the demands of the propulsion system are low. Tankers are one instance of this situation and any vessel with a substantial cargo discharging load also qualifies. Passenger vessels have a substantial electrical load which, although relatively constant, does involve a significant size of generator plant. There are advantages in having a single central power generation facility which can service the propulsion and all other ship loads as required.

5/17/2014 51 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

ECONOMICAL PART-LOAD RUNNING

•Again this is a concept that is best achieved when there is a central power generation system feeding propulsion and ship services, with

passenger vessels being a good example.

•It is likely that a typical installation would have between 4-8 diesel generator sets and with parallel operation of all the sets it becomes very easy to match the available generating capacity to the load demand. In a four engine installation for example, increasing the number of sets in operation from two that are fully loaded to three partially loaded will result in the three sets operating at a 67% load factor which is not ideal but also not a serious operating condition, It is not necessary to operate generating sets at part-load to provide the spare capacity to be able to cater for the sudden loss of a set, because propulsion load reduction may be available

instantaneously, and in most vessels a short time reduction in propulsion power does not constitute a hazard. 5/17/2014 52

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

• The propulsion regulator will continuously monitor the present generator capability and any generator overload will immediately result in controlled power limitation to the propulsion motors. During manoeuvring, propulsion power requirements are below system capacity and failure of one generator is not likely to present a hazardous situation.

5/17/2014 53 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

EASE OF CONTROL

•The widespread use of controllable pitch propellers (cpp) has meant that the control facilities that were so readily available with electric drives are no longer able to command the same premium. Electric drives are capable of the most exacting demands with regard to dynamic performance which, in general, exceed by a very wide margin anything that is required of a ship propulsion system.

5/17/2014 54 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

LOW NOISE

•An 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. With warships and survey vessels it is noise into the water which is the critical factor whilst with cruise ships it is structure borne noise and vibration to the passenger spaces that has to be minimised.

5/17/2014 55 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

• For very high power, the most favoured option is to use a pair of high efficiency, high voltage a.c. synchronous motors with fixed pitch propellers (FPP) driven at variable speed by frequency control from electronic converters. A few installations have the combination of controllable pitch propellers (CPP) and a variable speed motor. Low/medium power propulsion (1-5 MW) may be delivered by a.c. induction motors with variable frequency converters or by d.c. motors with variable voltage converters.

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Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

• The prime-movers are conventionally constant speed

diesel engines driving a.c. generators to give a fixed

output frequency. Gas turbine driven prime- movers for

the generators are likely to challenge the diesel option in

the future.

• Conventionally, the propeller drive shaft is directly driven from the propulsion electric motor (PEM) from inside the ship. From experience obtained from smaller external drives, notably from ice-breakers, some very large propulsion motors are being fitted within rotating pods mounted outside of the ship’s hull. These are generally referred to as azipods , as the whole pod unit can be rotated through 360° to apply the thrust in any horizontal direction, i.e. in azimuth. This means that a conventional steering plate and stern side-thrusters are not required. 5/17/2014 57

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

• Ship manoeuvrability is significantly enhanced by using azipods and the external propulsion unit releases some internal space for more cargo/passengers while further reducing hull vibration.

•Gradual progress in the science and application of superconductivity suggests that future generators and motors could be super-cooled to extremely low temperatures to cause electrical resistance to become zero.

5/17/2014 58 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

•Integrated electric-drive system derived from a commercially available system that has been installed on ships such as cruise ships requires a technology that is more torque-dense (i.e., more power-dense) .

•Candidates for a more torque-dense technology include a permanent magnet motor (PMM) and a high-temperature superconducting (HTS) synchronous motor.

•In addition, electric drive makes possible the use of new propeller/stern configurations, such as a podded propulsion ... that can reduce ship fuel consumption further due to their improved hydrodynamic efficiency

Marine Electric Propulsion

5/17/2014 59 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion

- Podded drives offer greater propulsion efficiency and increased space within the hull by moving the propulsion motor outside the ships hull and placing it in a pod suspended underneath the hull. - Podded drives are also capable of azimuth improving ship maneuverability. Indeed, podded drives have been widely adopted by the cruise ship community for these reasons. - The motors being manufactured now are as large as 19.5 MW, and could provide the total propulsion power.

5/17/2014 60 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Azipod drive unit

5/17/2014 61 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Propulsion motor

• For efficient operation of propulsion motor there is a requirement for a compact, power dense, rugged electrical machine to be utilized for the propulsion motor.

• For the full benefits of electric propulsion to be realized the machine should also be efficient, particularly at part load,

• In order to achieve suitable compact designs rare earth permanent magnet materials may be required.

• The machine topologies available for PMM are deemed to be those based on radial, axial and transverse flux designs.

5/17/2014 62 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

PMM

5/17/2014 63 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Marine Electric Propulsion Due to its flexibility, energy efficiency and superior performance,

electric propulsion is widely used in today's marine technology

Functionally the propulsion drive can be divided into following

parts :

• supply transformer,

• propulsion motor and

• frequency converter.

- In an AC drive, a frequency converter is used to control the

speed and torque of electric motor. The speed of the AC electric

motor can be controlled by varying the voltage and frequency of

its supply. A frequency converter works by changing the constant

frequency main electrical supply into a variable frequency output.

- The ideal simplicity of the induction motor, its perfect reversibility

and other unique qualities render it eminently suitable for ship

Propulsion. 5/17/2014 64 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Electric propulsion - Diesel-Generator sets to produce electricity to common grid for propulsion and ship use. - Variable speed drives to rotate fixed pitch propellers. - Commonly used in Cruise vessels, LNG tankers, Off-shore vessels and Ice breaking vessels due to reduced fuel oil consumption, lower emissions and increased pay-load

5/17/2014 65 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Generator system of Conventional Cargo Ships

Electricity demand is small.

2 Generators are equipped.

Only one set of either is usually operated.

Gen.

Gen.

Laod A

Laod B

Laod C

440V, 60Hz

Laod D

220V/110V

Photo from <http://ja.wikipedia.org/wiki/> 5/17/2014 66

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Features

Very big (24m, 15m)

Super heavy (2000 ton)

High Power (60,000 kW)

High Efficiency ( over 50% )

Large Diesel Engine for Main Engine

Photo from <http://www.mol.co.jp/ishin/engine/present/index.html> <http://www.mhi.co.jp/products/detail/mitsubishi-wartsila_diesel_engine.html>

Cleaner transport

5/17/2014 67 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion

System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Laod D

Main Engine

Propeller

5/17/2014 68 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power Converter

Power Converter

Motor

Motor

5/17/2014 69 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power Converter

Power Converter

Motor

Motor

5/17/2014 70 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion

Gen.

Motor speed can be controlled by the frequency of electric power.

Generator outputs constant frequency (60Hz)

Power converter supply suitable frequency and demanded power

Gen.

Power Converter Motor

Speed Control by frequency

Constant Frequency

60 frequency for control

5/17/2014 71 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion System for Ships

Gen.

Gen.

Power Converter Motor

Power Converter

Converter 60Hz AC DC

Inverter DC

Various frequency AC

5/17/2014 72 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion

System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power Converter

Power Converter

Motor

Motor

Harmo c Distor

5/17/2014 73 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Configuration of Electric Propulsion

System for Ships Special

Transformer for Power rter

Gen.

Pow Conver

Gen.

Pow Conver

Gen.

Laod A

Laod B

Laod C Gen.

er

ter Motor

er

ter Motor

Photo from <http://www.risho.co.jp/product/products3/special_use/converter/converter.htm> 5/17/2014 74

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Comparison with Conventional and

Electric Propulsion system

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power Converter

Power Converter

Motor

Gen.

Gen.

Laod A

Laod B

Laod C

Laod D

Main Engine

Propeller

5/17/2014 75 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Twin Shaft EL Propulsion

5/17/2014 76 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

FPSO Electrical system Layout

5/17/2014 77 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Shuttle Tanker Electrical System Layout

5/17/2014 78 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Shuttle Tanker Electrical Line Diagram

5/17/2014 79 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Drill Ship Electrical System Layout

5/17/2014 80 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Typical system of all electrical ship Generator sets complete with prime movers and engine controls

HV/LV Switchboards, distribution systems and group starter boards

Propulsion and thruster motors complete with power electronic

variable speed drives

Power conversion equipment

Shaft braking

Power factor correction and harmonic filters (as necessary)

Power management

Machinery control and surveillance

Dynamic positioning and joystick control

Machinery control room and bridge consoles

Setting to work and commissioning

Operator training

5/17/2014 81 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

THE FUTURE

• Propulsion of ships by help of standard diesel engines usually gives a non-optimal utilization of the energy.

• Today an increased use of diesel electrical propulsion of ships can be seen. New power electronics and electrical machines will be developed for propulsion and thrusters, as well as other application on board.

• Knowledge has to be developed about how such large motor drives will influence the autonomous power systems on-board.

• Even development of new integrated electrical systems for replacement of hydraulic systems (top- side as well as sub-sea) are becoming areas of need.

5/17/2014 82 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

To introduce solar energy to the ship we need to convert the solar energy to electrical energy. electrical energy we can use and transport throughout the ship. photo-voltaic cells convert solar into electrical energy. An inverter is needed to convert the direct current (dc) to an alternating current (ac), so the 50 or 60 hz electric grid can transport the electrical energy through the ship. These energy conversions reduce the efficiency of the whole chain. With a dc grid in a diesel-electric propulsion system less energy conversions are needed, There is no need for bulky transformers.

WIND & SOLAR ENERGY FOR SHIP

5/17/2014 83 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Ships also can benefit from the sun. The deck of a ship is always outside in the sun. With a deck area of more than 9000 square meters for a Panamax sized ship, a lot of energy can be harvested for free. With increasing PV-panel efficiency and decreasing cost due to mass production, solar energy can be beneficial next to existing ways to produce electrical energy. There are of course some challenges to overcome before integrating solar energy on a ship, but the maritime industry is driven by innovation to come with clever solution. Ship already sailing solely on solar energy is the planet solar. With its 500 square meters of solar panels and large li-ion battery, it is accomplishing a journey around the world.

WIND & SOLAR ENERGY FOR SHIP

5/17/2014 84 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Sail and solar power ship

5/17/2014 85 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

SKYSAIL TECHNOLOGY

5/17/2014 86 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

SKYSAIL TECHNOLOGY

5/17/2014 87 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

POWERFUL - UNLIMITED - FREE Wind is the cheapest, most powerful, and greenest source of energy on the high seas. Now, with SkySails, modern cargo ships can use the wind as a source of power – not only to lower fuel costs, but significantly reduce emission levels as well.

SKYSAIL TECHNOLOGY

5/17/2014 88 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

The worldwide patented SkySails propulsion system consists of three main components: a towing kite with rope, a launch and recovery system, and a control system for automated operation. SkySails can be installed effortlessly as an auxiliary propulsion system on both new builds and existing vessels. The SkySails propulsion system is efficient, safe, and easy to use – and the fact that wind is cheaper than oil makes SkySails one of world’s most attractive technologies for simultaneously reducing operating costs

and emissions.

SKYSAIL TECHNOLOGY

5/17/2014 89 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Reference Articles, Books and Websites: 1. Electric Propulsion Systems for Ships by Dr. Hiroyasu Kifune 2. Practical Marine Electrical Knowledge by D.T. Hall 3. www.vht-online.de (Speech by Bernd Röder) 4. www.imtech.com 5. www.skysail.info

5/17/2014 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh 90

Any Question?

Thank you!

5/17/2014 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh 91