Some Options for Future Marine Propulsion

International Union of Marine Insurance Conference

Paris: 18th to 21st September 2011

Some Options for Future Marine Propulsion



Photovoltaic Arrays



Photovoltaic arrays convert

sunlight into electricity.

Fuel consumption reduction is

proportional to array installed

area.

Low efficiency requiring large exposed surface area.

Typically 10 to 20% - 45% maximum from laws of physics.

Up to 60% with concentrating lenses and mirrors.

40 kW shipboard installation under evaluation.

Photovoltaic arrays



Power Assistance From The Wind



Different types of wind assisted propulsion

Static Traction Rotating Dynamic Traction

Wing Sail Flettner Rotor

Kite Rig

Soft Sail Wind Turbine



Rotor-wind interaction designs

As with sail designs, the fatigue life of the rotors is of considerable importance.

Rotor dynamics requires definition. • Intrinsic rotor dynamics. • Vortex shedding. • Mutual interference.

Overturning moments and loads

imposed on the hull structure.

Control of rotors, maximum rotational speeds and wind conditions.



Full scale wing sail studies Over the years many organisations,

including classification societies, have

conducted full scale investigations into

the performance of sails applied to

merchant ships



Kite assistance

Kites outperform conventional sails.

Require a control system to set and

operate the system.

They can provide a proportion of the

energy required for ship propulsion. [A 12500 teu container ship requires some 60-70 MW]

Operational envelope restrictions in

poor weather.

Possibility of a navigational hazards.



Fuel Cells



Fuel cell technology

Chemical to electrical energy without combustion -

2H2 + O2 → 2H2O + thermal energy + electrical energy

high electrical conversion efficiency

high energy density

no harmful emissions

solid state

silent.



30

40

50

60

70

Thermal

Efficiency

[%]

Gas turbine (natural gas simple cycle)

High speed diesel (MDO)

Fuel cell (natural gas combined cycle)

Medium speed (natural gas) Medium speed diesel (MDO)

Gas turbine (natural gas advanced)

Slow speed diesel (HFO)


Fuel cell (natural gas simple cycle)

Gas turbine (natural gas combined cycle)

Fuel cell (hydrogen simple cycle)




Until worldwide hydrogen infrastructure exists or revolutionary

breakthrough in hydrogen storage technology is made, marine fuel

cells need to operate on hydrocarbon fuels.

Operation on residual fuels is unlikely and operation with marine

distillates is theoretically possible but remains significant challenge.

More likely in the near term is operation on emerging marine fuels

such as natural gas or methanol.

Longer term, the solid polymer or solid oxide fuel technology looks

the most promising for marine propulsion.



Nuclear Propulsion



Nuclear propelled ships

Since then the applications to merchant ships have included:

o NS Lenin [Ice Breaker]

o NS Savannah [Passenger/Cargo]

o NS Otto Hahn [Cargo]

o NS Mutsu [Cargo]

o Russian ice breaker classes

o NS Sevmorpot [Lash Barge/Container]

o NS 50 Let Povbedy [Ice Breaker/Cruise Ship]

Since the first application of nuclear propulsion to ships some 700 reactors have served at sea.

Today about 600 reactors are operational of which one third are serving at sea.

The nuclear propulsion of ships and submarines started with the USS Nautilus, some 55 years ago.



Nuclear merchant ship project studies

There have been a number of project studies since the time of the early

demonstrator merchant ships: Savannah, Otto Hahn, etc.

For example:

1974 415000 dwt Twin Screw Tanker.

2 x 60000 shp – 21 knots.

Proposal to build 12 ships.

2008 9200 teu Container Ship.

1000 MWt – 35 knots – Break even oil price 89 US$/barrel.

Trans – Pacific Route

Proposal to build 3 ships to replace 4 operating at 25 knots.

Today There are about 12 or 15 studies going on around the world.



Energy release during fission

The energy released from the fission of 235U comprises a number of components:

The kinetic energy of the charged fragments of fission. 162MeV

The fission neutrons. 6MeV

Fission gamma rays. 6MeV

Subsequent beta and gamma decay. 10Mev

Neutrinos. 11MeV

[1MeV = 1.598x10-3 J]

The total energy release is, therefore, about 195 MeV per fission event.

For a 12500 teu containership undertaking a 3500 nm voyage at 25 knots

the fuel requirement would be about 3.4 kg of 235U, making no allowance

for the fissile products generated in the reactor from the enriched uranium

fuel. If these were taken into account then the mass of 235U would be of

the order of 2.2 kg. The equivalent residual fuel burnt would be 1540 tonnes.



The choice of marine reactor

Most experience to date has been with PWR designs and this is likely to be the

choice for early designs.

Subsequent developments may include high temperature reactors, pebble bed

designs and thorium. Similarly, in time nuclear batteries may become tenable.

The design could be based on:

Direct drive steam turbines.

Or, more likely, turbo-

generator concepts - this

latter concept would permit

more efficient steam cycles.



Pressure plant and structure design

• ASME III Code is applicable to the design of nuclear pressure

components: Pressure vessels, piping, etc

Design for piracy – missile, aeroplane strike, etc.



Reactor location

To give the reactor the best environment in which to operate from a sea induced motions and vibration perspective.

Reactor control longevity and fretting potential of the fuel rods in the core.

Longitudinal and transverse collision protection using elasto-plastic energy design principles



Refuelling

The design of the spent fuel removal facilities on board to meet the constraints of radiation physics and health safety is a key area. This may be after 5 to 7 years, given enrichment levels between

3.5% and 5%. Permanent retention on board, even given the correct cooling and radiation protection, will not be permitted by the IAEA.

The removal of spent fuel and the refuelling process will take about 30 days in a dedicated port facility.

The removal system will have to be designed into the ship. This most probably would take the form of dedicated passages through side shell doors on to the quay.

Reception facilities would be required – typically, similar to those currently deployed for naval vessels in various parts of the world.



Technical case studies

Type Tanker/Bulk Carrier Container Ship Cruise Ship

Capacity 300000

dwt

1000000

dwt

7450 teu 12500 teu 1500

Passengers

5400

Passengers

Ship speed 16 knots 16 knots 23 knots 25 knots 21 knots 22 knots

SHP 30 MWe 78 MWe 40 MWe 77 MWe 52 MWe 105 MWe

PWR

Capacity

120 MWt 290 MWt 150 MWt 285 MWt 200 MWt 390 MWt

Plant Type PWR Steam

Direct

PWR Steam

Direct

PWR Steam

Turbo/Elect

PWR Steam

Turbo/Elect

PWR Steam

Turbo/Elect

PWR Steam

Turbo/Elect

Number of

Propulsors

1 FPP

3 FPP

1 FPP

1 FPP

2 Podded

3 Podded



Nuclear ship operation

Health Physics

Officer and Crew Training

Safety Culture

Employment Contracts Terrorist Threats

Changing General Public

Perception

Radiological Protection

Ports and Local

Populations

Dry-dock, Maintenance

and Refuelling

Ship Manning Levels and

Organisational Structure

Working within the ship’s safety

case: design, construction,

operation and disposal.



Port entry ~ flag state acceptance

The IAEA - IMO relationship.

Flag state and acceptance of certification.

Land based nuclear regulator involvement.

The role or need for designated ports.

Acceptable locations for maintenance activities.

The current Royal Academy of Engineering

Working Group findings.

Port and Flag State responses will be significant in any future

development of nuclear propulsion.



Concluding Remarks

The world is looking for CO2 solutions. Much that can be done with existing infrastructure.

Wind power has some potential for making a contribution.

Fuel cell technology clearly has potential in medium to long term.

Photovoltaic methods are probably limited to auxiliary power contributions. Nuclear powered vessels

• Large marine experience • Technically understood • Perception issues • Operational changes • Regulation changes

Some Options for Future Marine Propulsion

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