1. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 1
The Future of Marine Propulsion: Gas Hybrid Power Plants
Edward James Eastlack
Marine Engineer
New Orleans, LA, USA
edeastlack@gmail.com
ABSTRACT
Rising fuel costs and increasingly stringent emission
standards for the marine industry have caused ship
owners to look at a wide range of marine
technologies to meet environmental compliance and
to reduce lifecycle costs. Emissions can be reduced in
many ways including improved fuel quality,
improved plant efficiency and after treatment. With
distillate fuels, residual fuels and after treatment
having high cost and equipment lifecycle costs, LNG
appears to be the clear choice for helping the marine
industry to meet these new emissions standards. The
carbon footprint of a vessel can also be reduced by
improved efficiency. Optimized natural gas prime
movers and electrical systems can assist in achieving
these efficiency targets. The International Maritime
Organization (IMO) has also adopted greenhouse gas
reduction measures by requiring an International
Energy Efficiency Certificate (IEEC) and Ships
Energy Efficiency Management Plan (SEEMP) for
existing vessels and an Energy Efficiency Design
Index (EEDI) for new build vessels after January
2013. Therefore, the industry must now address both
emissions and plant efficiency. As a result, there is
also increasing interest in fuel efficient “hybrid”
propulsion/electrical systems. The latest systems use
a common prime mover that does not have to have a
fixed frequency to accommodate the electrical
system. Several new system designs are adopting this
concept where generators are able to operate at
variable speed, and all outputs go into a common DC
grid or bus system. From there, the DC is converted
to whatever voltage and frequency a particular load
or system needs, using VFD technology to achieve
improved plant efficiency or fuel economy.
Hybridization of the power plant can improve the
transient response of gas engines as well as provide
additional load profile flexibility and reduced running
hours on the prime movers which translates to
improved efficiency and reduced carbon emissions.
These alternative sources of energy are easy plug and
play options to the existing DC grid or bus system.
There are many options for hybridization to include
high powered lithium battery banks, wind turbines,
solar panels, fuel cells, super capacitors and micro
turbines. The Organic Rankine Cycle using
refrigerant or critical CO2 gas has also gained
acceptance as an effective means to recover waste
heat from low heat sources such as engine jacket
water and exhaust gases, thus, improving plant
efficiency even further. Optimized bow, hull,
propeller and rudder design are additional ways to
improve efficiency and reduce carbon emissions. Gas
hybrid power plants with waste heat recovery
systems and optimized hydrodynamics offer ship
owners the right combination of marine technologies
needed to reduce fuel consumption, emissions,
lifecycle costs as well as improved reliability and
durability of shipboard propulsion systems.
INTRODUCTION
In order to reduce the carbon footprint of the global
marine industry, the International Maritime
Organization (IMO) has adopted a greenhouse gas
reduction regime from a marine power plant
efficiency standpoint. Improving power plant
efficiency essentially involves burning less fuel and,
thus, emitting less carbon to the atmosphere. IMO
power plant efficiency requirements for existing
vessels include a Ship Energy Efficiency
Management Plan (SEEMP) and International Energy
Efficiency Certificate (IEEC) and are required after
January 1, 2013. The SEEMP and IEEC are
retroactive to existing vessels and will be required to
retrofit marine technology that results in a 10% plant
efficiency improvement at the next regularly
scheduled dry dock after 2013. New build vessels
will additionally be required to have an Energy

2. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 2
Efficiency Design Index (EEDI). Gas hybrid
propulsion is the perfect combination of marine
technologies because it provides reduced emissions
and improves power plant efficiency. The emissions
benefits come from burning clean and abundant fuel
(natural gas) and the increased efficiency of a hybrid
electrical propulsion system.
MEDIUM SPEED (OTTO CYCLE) LEAN BURN
NATURAL GAS SPARK IGNITION ENGINE
The Bergen B35:40 is a good example of a lean burn
Otto cycle spark ignition marine gas engine currently
available. The emissions of this engine meet all
current and future requirements to include Tier 4
without after treatment. The Bergen lean burn spark
ignition gas engine operates according to the Otto
Cycle using a lean mixture of gas and air as it is
compressed and ignited by an electric system. A lean
burn engine operates at air excess ratios of 1.8 and
higher, and as the illustration shows, this gives
increased power, efficiency and reduced NOx
emissions. This is achieved by improving the
combustion system so that the ignition energy is
capable of firing such lean mixtures reliably.
Additionally, a highly efficient turbo charging system
is used to take advantage of the possible power
increase offered by the extended knock limit of lean
mixtures. Air is drawn in by the turbocharger through
the charge air cooler and into the cylinder. A timed
mechanical gas valve injects gas into the inlet air
stream to ensure a homogenous and lean mixture of
air and gas. Air flow is controlled by the variable
turbine geometry of the turbocharger while gas flow
is controlled by mechanical valves before each
cylinder. The gas pressure is set electronically by the
pressure regulating valve on the fuel gas supply
module ahead of the engine. An air flap for each
cylinder restricts the air supply during start-up and
low load operation. As the pressure in the cylinder is
low, gas is admitted into the small pre-chamber in
each cylinder head, electronically controlled by the
pre-chamber pressure unit. During compression, the
lean charge in the cylinder is partially pushed into the
pre-chamber, where it mixes with the pure gas to
form a rich mixture that is easily ignited by the spark
plug. This powerful ignition energy from the pre-
chamber ensures fast and complete combustion of the
main charge in the cylinder. Advanced electronic
engine management ensures the operating parameters
of the engine are adjusted and optimized in relation to
each other. The system sets the optimum main and
pre-chamber gas pressures, air/fuel ratio, fuel rack
position, ignition timing and throttle position. The
alarm and monitoring part of the system features
many built-in safety functions. It combines safe
operation with high availability, protecting the engine
and signaling any fault. It includes a misfiring
detection system based on analyzing different
operational parameters and a knock detection system.
The system detects and eliminates knocking
individually for each cylinder. The complete engine
management, control and monitoring system fits into
a cabinet next to the engine and communicates with
the plant control through one simple cable (RR).
Figure #1. Hybrid Propulsion. Retrieved from “Bergen B35:40 gas engine,” by
Rolls Royce Power Engineering June, 2009.
NEW GENERATION ELECTRIC PROPULSION
SYSTEMS (DC GRID)
The Siemens Blue Drive Plus concept implements a
new control philosophy into the traditional diesel
electric propulsion systems such as variable speed
operated diesel engines and load shifting. This
technology makes possible low emissions of
greenhouse gases, low fuel consumption, and full
utilization of gas/dual fuel systems and SCR systems
to reduce NOx emissions. Additional benefits are
extended maintenance intervals of the prime movers,
reduced space requirement for the electrical system,
increased efficiency of the electrical system, clean
power supply to the auxiliary consumers and no
rectifier transformers.
Prime mover speed control is possible through the
whole speed range of the engine. The control system

3. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 3
will dynamically set the speed according to the
optimal operating point of the engine which is
essentially the lowest possible specific fuel
consumption (g/kWh). During DP operation, the
advantages are substantial as production and even
spinning reserve can be realized with limited
consumption, emissions and maintenance cost. In
low load situations the power management system
will load shift to one engine or alternative power
supply if the system is hybridized. There is a need for
some predication software based on history or pre-
determined trip performance for low load conditions.
Also, the ramp up time of the engines for large step
loads is longer as the mass needs to be accelerated
and the turbochargers need to become active from the
lower flow rates over the turbines. Therefore, with
some of these engines, optimization of the engines is
needed, or multi stage turbo charging, or turbo
bypass at low loads. The system also has the
capability to shift load from port to starboard as
required.
Electrical power generation is typically accomplished
using synchronous generators designed to operate at
the same speed or power range of the connected
prime mover. The Blue Drive Plus system makes it
possible to consolidate the generator, bus-tie panel,
and frequency converters for all auxiliary drives. If
DC distribution is used a separate inverter may be
required depending on the application. For general
service loads the AC inverter might be consolidated
to a particular load center but large electric motors
would have their own to reduce power consumption.
Harmonic distortion associated with rectifiers and
frequency converters is effectively isolated by the DC
bus unless there are loads coming directly off the
main generator before the inverter which is not
typical. This consolidation allows for clean power to
be supplied to all auxiliary consumers and reduces
the total package footprint by 30%.
Figure #2. New Diesel Electric Propulsion System. Retrieved from Blue Drive
Plus C,” by Siemens Corporation July, 2010
The new control philosophy monitors all generator
control, drives control and power management
functionality in one unit. The speed and power of the
prime movers are controlled in correspondence with
the total power consumption of the vessel. The
electric system is only fed with active power from the
generators, thus, eliminating the need to handle
reactive power. The speed and power characteristics
of the prime mover will be parameterized. There are
three main integrated components that make the Blue
Drive Plus system which include the power
management system, the power plant protection and
generator power adaption systems. There are two
parts to the Power Management System. The first is
total load versus available power. There is also a
follow up that occurs with the DC system and that is
optimizing engine load against fuel consumption and
engine speed. The latter is controlled by a data base
of the engine fuel consumption performance at
different speeds and load capability. Once the load
per engine is known, the system will match the best
fuel consumption figure and set the engine speed
accordingly. The system uses an algorithm that will
perform fast differential equations to find the
minimum fuel consumption. The fuel flow metering
system for the engine provides the needed feedback
to the system. The control system uses fast computers
able to perform the necessary calculations and also a
power system that is not speed dependent. AC
systems are speed dependent which require
isochronous governors which essentially put a lot of
unnecessary wear and tear on the engine due to
constant adjustment of the fuel rack to maintain
constant speed.
The DC system power basically comes from
alternators connected to solid state rectifiers which

4. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 4
effectively stop reverse power issues, but the
rectifiers can be active front end types that can adjust
the alternator performance to unity power factor as
well, reducing conductor sizes and installation costs.
Active front ends on drives and rectifiers means they
are adjusting the firing angles of the rectifiers to
achieve a unity power factor or in some cases
negative. In this way a conventional vessel with a lot
of the AC to DC drives can use these devices to
correct system power factor as well as provide
rectification.
Figure #3. Fuel Consumption Comparison. Retrieved from Blue Drive Plus C,”
by Siemens Corporation July, 2010
This might be typical on some newer offshore vessels
or ferries. This essentially means a smaller generator
and cables due to reduced AC current. If there are no
AC loads directly on the generator from the vessel
this is not an issue because the power factor can be
adjusted with an automatic voltage regulator
depending on the vessel requirements. The engine,
although turning slower can have reduced speed
effect on voltage compensated for by excitation
control. The DC grid also makes it easier to connect
to shore power regardless of voltage and frequency
differences. A back up battery bank can charge while
connected to shore power and be a temporary source
of power while in port. The DC Drive concept makes
new energy sources a plug and play option, so your
drive system essentially never becomes obsolete.
HYBRIDIZATION OPTION 1&2 - WIND TURBINES
AND SOLAR PANELS
An effective power plant hybridization option is wind
turbines and solar panels. This is an easy plug and play
option to the DC Power Grid concept.
Solar panels are virtually maintenance and are ideal for
charging storage batteries. The photovoltaic Cells are
encapsulated between a tempered glass cover and an
EVA pottant with PVF back sheet. The entire laminate
is installed in an anodized aluminum frame for
structural strength and ease of
installation.
Solar panels are designed to convert sunlight into
electricity. The current and power output of a solar
panel or photovoltaic module is approximately
proportional to sunlight intensity. At a given
intensity, a module’s output current and operating
voltage are determined by the characteristics of
the load. If that load is a battery, the battery’s internal
resistance will dictate the module’s operating
voltage.
Wind turbines and solar panels can be mounted in
various configurations onboard a wide variety of
vessels to harness wind and solar energy which is very
abundant out at sea. The type of vessel will determine
the best configuration for optimizing the available
energy. A wind turbine is a rotor blade driven 3-phase alterna
designed for low speed operation. The rotor component
includes the blades for converting wind energy to low speed
rotational energy. The generator includes the windings,
gearbox and transmission which converts the low speed
rotational energy to electrical energy. These machines are
extremely efficient in low wind speeds yet capable of
producing 500 watts or more depending on allowable space
(TMP). This technology allows the vessel to harness
renewable energy to reduce fuel consumption and
greenhouse gas emissions. This technology
can also assist a ship owner to meet the ever changing
MARPOL regulations.
HYBRIDIZATION OPTION 3 - HIGH POWER LITHIUM
BATTERY BANKS
Power plant hybridization is also possible using
lithium polymer ion batteries. These batteries have
been used for commercial and military marine
applications. A typical battery bank will include a

5. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 5
battery management system with connecting cables
and communication harnesses to the vessel systems.
The battery modules can be combined to produce
megawatts of power that can replace a prime mover.
These battery banks can act as the sole energy source
for low load situations, handle peak loads without
starting standby generators and act as an energy
buffer. This energy buffer will optimize fuel
consumption, emissions, lifecycle cost and transient
response to power demands. This is especially
important for gas engines which have slower
transient response than their diesel counterparts.
HYBRIDIZATION OPTION 4 - FUEL CELLS FOR
MARINE APPLICATION
Another marine power generation option using
natural gas for fuel is a marine application of a fuel
cell. Wartsila is currently developing fuel cell
technology for marine application in the power range
of 5MW. The Wartsila FC50 is 50KW and the FC250
is 250KW. Scalable systems will be available up to
5MW.
Figure #4. Wartsila Solid Oxide Fuel Cell. Retrieved from Wartsila Fuel Cell
Program,” by Wartsila Corporation July, 2010
Commercial marine applications are targeted for
auxiliary power units. This technology could also be
integrated as part of a hybrid solution for propulsion
systems in conjunction with combustion engines. The
hybrid solutions between the ship’s main engine and
fuel cells are systems available through Wartsila,
Siemens, ABB, Converteam as well as others. Fuel
Cell technology using natural gas as fuel offers ultra
low emissions and high thermodynamic efficiency
which makes for an excellent application for
coastwise shipping, inland waterway and offshore
applications and operations inside the North
American Emission Control Areas. The high
operating temperature of SOFC technology
enables co-generation where the high value exhaust
heat can be utilized in marine
applications to produce electricity, steam and
cooling—even freezing, depending on the vessel
type. Recovery of the waste heat which is a
byproduct of the chemical reaction can raise the
efficiency to as high as 90%. Additional byproducts
of the chemical reaction include water, electricity and
small amounts of NO2 depending on the fuel source.
Fuel Cell benefits include high efficiency (40-60%),
ultra low emissions, low noise, no vibrations, co-
generation, fuel flexibility, high part load efficiency,
high reliability and availability (WC).
Figure #5. Diagram of Fuel Cell Process. Retrieved from Wartsila Fuel Cell
Program,” by Wartsila Corporation July, 2010
The fuel cell works by passing streams of fuel and air
over electrodes (anode and cathode) separated by an
electrolyte. This produces a chemical reaction that
generates electricity without requiring the
combustion of fuel or the addition of heat typically
required in traditional primemovers and provides
another method for producing electricity from fossil
fuels (natural gas).
HYBRIDIZATION OPTION 5 – SUPER CAPACITORS
Another hybridization option is the use of super
capacitors. Super capacitors can provide stability and
efficiency to the DC grid. A super capacitor can
provide a few seconds to a minute of reactive power
in cost effective package. A 20 foot container can
provide 1MW of power for 1 minute. Super
capacitors have a longer life than lithium battery

6. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 6
banks and are ideal for shipboard application because
of their superior high power charge/discharge cycling
with lifetimes over a million charge/discharge cycles
at 100% depth of charge (MT).
EFFICIENCY IMPROVEMENT OPTION 1 - RANKINE
CYCLE AND EXHAUST GAS WASTE HEAT
RECOVERY (CO2)
The Rankine Cycle when using super critical CO2 as
the working fluid can eliminate the need for using
thermal oil as the intermediate working fluid because
super critical CO2 has very high thermal efficiencies
at temperatures above 500C and 20 Mpa. For
example, capturing exhaust gas waste heat using CO2
would allow for the CO2 to be circulated directly
through the exhaust gas heat exchanger and power
the turbo alternator directly, making electricity. A
Caterpillar G3516 engine has 863F exhaust
temperature and 20526 lb/hr exhaust flow rate at
100% load. The compromise is the higher working
pressure for a super critical CO2 system is around
3000 psi.
A system like this using CO2 as the working fluid
would require high speed turbine alternator power
electronics to deliver the required DC voltage would
be needed to plug and play into a DC grid system.
The turbine can be custom made to add
approximately 10-20% efficiency to any primemover
without taking up a lot of space. This can be
megawatts of power depending on the size of the
prime mover producing the waste heat. A high
pressure pump is needed to establish super critical
pressure. This pump located on the outlet side of the
condenser is electrically driven. A recuperator is used
to improve process efficiency and reduce the net
losses of running an electrical pump. A condenser is
used to liquify the CO2. The exhaust gas heat
exchanger consists of a finned-tube coil attached to
the prime mover exhaust piping after the
turbocharger. It is designed to capture waste heat
from the exhaust stream and apply it to the Rankine
Cycle working fluid circulating through the coil.
Figure #6. Diagram of Super Critical CO2 Rankine Cycle. Retrieved from
Marine and Power Engineering Products,” by Marine and Power Engineering
Inc February, 2012
.
EFFICIENCY IMPROVEMENT OPTION 2 –
OPTIMIZED HYDRODYNAMICS
Improved bow design can reduce hull resistance and
improve fuel efficiency. The new bow design
developed by Rolls Royce gives better performance
in a seaway, less speed reduction, reduced
accelerations and less risk of hull plate deformation
in the fore body in high seas. The design combines a
vertical leading edge with a bulbous lower section
and flares in the upper section. The design was
developed using computer simulation an 8 percent
reduction in resistance when compared to a
conventional raked bow with bulb. Accelerations in
the forward part of the vessel are reduced by 10
percent. The use of computational fluid dynamics
assisted with optimizing the hull for reduced
resisitance. The computer based work was verified in
tank testing models. Rolls-Royce is applying the bow
design to a wide range of vessel types such as
passenger, ropax and roro ships, chemical and
product tankers, LNG/LPG Tankers, bulk carriers,
LNG bunkering vessels and superyachts. This bow
design is also easier to construct as it has fewer
double curvature plates and can be lighter due to the
reduced impact from the waves (ID).
EFFICIENCY IMPROVEMENT OPTION 3 –
OPTIMIZED PROPELLER AND RUDDER DESIGN
Improved propeller and rudder design is another
efficiency improvement option. Rolls Royce has an
integrated rudder and controllable pitch propeller
system (Promas) which improves propulsion
efficiency by 5 to 8 percent. There is a strong low

7. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 7
pressure vortex behind a traditional propeller that acts
on the propeller hub increasing drag and reducing
propeller thrust. A special hubcap is fitted to the
propeller, which streamlines the flow onto a bulb that
is welded to the existing rudder, effectively reducing
flow separation immediately after the propeller. The
result is an increase in propeller thrust as previously
wasted energy is recovered from the flow. The
addition of the bulb on the rudder also streamlines the
flow aft of the rudder, further reducing drag. The
hubcap is mounted outside the propeller hub and acts
purely as a hydrodynamic fairing and no special hub
design is needed, with cost and technical complexity
kept to a minimum. Adopting the twisted rudder
design of the Promas system can yield further
improvements in efficiency and maneuverability
(ID). This kind of system can be installed during a
regularly scheduled dry docking and is a simple
retro-fit to improve power plant efficiency and meet
the impending IMO efficiency requirements for
existing vessels as well as newbuilds.
CONCLUSIONS AND RECOMMENDATIONS
A ship owner that is aware of the regulatory
requirements for marine power plant emissions and
efficiency will be well positioned to keep existing
vessels compliant as well as design newbuild vessels
to meet the EEDI. Environmental compliance
measures mandated by the IMO to reduce emissions
from a power plant efficiency standpoint puts a new
twist on the increasingly stringent emissions
reduction regime. This leaves the owner with existing
vessels that must be retrofitted with efficiency
improving technologies. Fuel quality can also
improve emissions and reduce carbon emission.
Thus, giving renewed motivation to switch to LNG.
Power plant efficiency can also be improved by an
optimized electrical distribution system such as a DC
bus or grid. In a DC grid system the generators
operate at variable speed and all outputs go to a
common DC grid. The DC is then converted to
whatever voltage and frequency a particular load or
system needs, using VFD technology to achieve
improved plant efficiency or fuel economy.
Additional improvement to plant efficiency is
achieved with several power plant hybridization,
waste heat recovery and hydrodynamic optimization
options. The power management system senses the
available energy sources on the grid such as
optimized gas engines, capstone micro turbines, fuel
cells, wind turbines, solar panels, or super capacitors.
Depending on the existing load, the power
management system will load shift to the best
applicable energy source as required. This allows for
load profile flexibility and thus operational flexibility
of the power plant. The Organic Rankine Cycle,
using an applicable working fluid such as an
environmentally friendly refrigerant gas like R245fa
or critical CO2, is another effective option to raise
power plant efficiency by recovering heat from
engine exhaust or jacket water and creating DC
power that plugs right into the grid. Optimizing the
bow, hull, propeller and rudder can also improve
efficiency. Hybridized marine power plants using
natural gas for fuel, waste heat recovery systems and
optimized hydrodynamics offer ship owners the right
combination of marine technologies needed to reduce
fuel consumption, emissions, lifecycle costs as well
as improved reliability, operational flexibility and
durability of shipboard propulsion systems.
REFERENCES
CE. (2012, Jan). Hybrid marine propulsion. Corvus Energy.
http://www.corvus-energy.com/marine.html.
EMP. (2012, Jan). Wind and solar power for ships. Eco Marine Power.
www.ecomarinepower.com/en/wind-and-solar-ships
ID. (2011, Nov) Innovative Gas Powered Design. In Debth.
http://www.rolls-
royce.com/about/publications/marine/indepth/16/files/assets/downloads
/publication.pdf
MEPC. (2011, July). Mandatory energy efficiency measures for
international shipping adopted
at IMO environment meeting. Marine Environment
Protection Committee – 62nd
Session.
http://www.imo.org/MediaCentre/PressBriefings/Pages/42-
mepc-ghg.aspx
MPE. (2012, Feb). Super critical CO2 Rankine Cycle Waste Heat
Recovery System. Marine
and Power Engineering, Inc.
www.marineandpower.biz/page9.html
MT. (2012, Feb). Ultracapacitor grid storage solutions. Maxwell
Technologies.
www.maxwell.com/products/ultracapacitors/industries/grid-
storage
RR. (2009, April) Bergen B35:40 gas engine. Rolls Royce.
http://www.rolls-
royce.com/marine/products/diesels_gas_turbines/gas_engines/
SC. “Blue Drive Plus C” Siemens Corporation, Jan, 2007.

8. Paper No. ICETECH12-XYZ-R0 Eastlack Page number: 8
http://www.nwe.siemens.com/norway/internet/no/produkter/e
nergy/marine/Pages/Newdieselelectricpropulsionsystem.aspx
TMP. (2012). Wind Generators. Trans Marine Pro.
http://www.transmarinepro.com/wind-generators.html
WC. (2005, Jan). Wärtsilä fuel cell program. Wärtsilä Corporation.
http://www.fuelcellmarkets.com/images/articles/W%C3%A4
rtsil%C3%A4%20Fuel%20Cell%20Program.pdf
AKNOWLEDGMENTS
I would like to thank Professor William Sembler for
his guidance and support during my courses of study.
This course of study has led to my involvement with
the Gulf Coast Advisory Council on the use of LNG
as a Marine Fuel. The Gulf Coast Advisory Council
is led by David Braxton Scherz of Det Norske Veritas
(DNV).
The California State Lands Commission has asked
me to sit on their “Future Fuels” panel at the 2012
Onshore and Offshore Pollution Prevention
Symposium in October 2012.
www.slc.ca.gov/Division_Pages/MFD/Prevention_Fi
rst/Prevention_First_Home_Page.html I will also be
making a presentation covering key points from my
research on LNG as a viable marine fuel.
The work being done by the GMU Consortium
Advisory Committee for promotion of U.S. Marine
Highways should also be acknowledged.
http://eastfire.gmu.edu/gmu-consortium/marine-
highway/document/GMU-Mar-Hwy-Res.pdf This
work is vital to the country buying into a more
efficient marine transportation system and, hopefully,
choosing LNG as a cost effective and
environmentally friendly fuel. The abundance of
natural gas represents energy independence for the
United States and essentially marine transportation
independence. Coastwise Jones Act new build vessels
will be prime candidates for gas hybrid propulsion
plants due to their frequent operation in the
Environmental Control Areas which will require a
cleaner fuel and more efficient power plant to meet
the ever increasing emissions and energy efficiency
standards.
The enormous response from people in the Industry
who are responsible for the new build programs as a
result of my thesis, Natural Gas as a Viable Marine
Fuel in the US, must also be acknowledged.
Environmental compliance of their vessel fleets is a
key issue to be addressed. The economic and
environmental benefits of gas hybrid propulsion
systems will take any fleet owner to the next level.
The benefits of natural gas as a fuel has been known
for a long time, but has only recently been recognized
globally due to a lack of understanding of the
intricacies of working with LNG in this regard. It is
my hope that this paper and my previous paper
“Natural Gas: A Viable Marine Fuel in the
US,”http://www.maritime-
executive.com/article/natural-gas-a-viable-marine-
fuel-in-the-united-states will help remove previous
roadblocks in this respect and help to initiate new
build programs and conversion projects,
incorporating proven marine technology that provides
lower emissions and higher efficiencies.
APENDIX A