Appendix E

Technology Evaluation
E - 1

Feasibility of Using Existing Emission Control Technologies for 

Marine Applications

There are a number of control technologies that have been proven to reduce

emissions of oxides of nitrogen (NOx) and particulate matter (PM) from dieselfueled engines used in on-road, and off-road, applications. While, in theory many 

of the control technologies used in land-based applications could potentially be 

marinized to work in the marine environment, the potential success of these 

methods when applied to harbor craft will be highly dependent on the specific 

application. Considerations for applicability include the engine duty cycle, engine 

placement in the hull, vessel exhaust system configuration, and age of specific 

harbor craft. Since most marine vessels are custom built and have vastly 

different engine room configurations with varying capacity for space in which to 

install after-treatment emission controls, it is unlikely that there will be “off-theshelf” or “one size fits all” aftertreatment devices available for harbor craft. It is 

likely that the control devices will also need to be customized to each vessel 

configuration. Nevertheless, we believe that over the next several years, there 

will be increased desire to develop control technologies for marine applications to 

help mitigate the emissions that occur in and around ports and urban centers. 

In this appendix, brief descriptions of NOxand PM emission reduction control 

strategies currently used in general diesel engine applications will be presented. 

Some of the control technologies presented have been recently introduced to use 

in the marine environment. We believe many of the control technologies 

presented here can be used in the marine environment, but, at this time, there 

are no control technologies that have been verified for marine applications 

through the ARB verification procedure.

Descriptions of a number of demonstrations of different control technologies are 

provided in this appendix as well as the current status of engine replacements 

that have occurred under the Carl Moyer Memorial Air Quality Standards 

Attainment Program.

Diesel PM Exhaust After-treatment Emission Controls

The principle exhaust treatment technologies that have been successfully used 

to reduce diesel PM from diesel-fueled engines used in land-based applications 

are diesel particulate filters (DPF), diesel oxidation catalysts (DOC), and flow 

through filters (FTF) (or combinations of technologies). Each of these are briefly 

described below.

Diesel Particulate Filters

DPFs have been successfully used in many applications, including stationary

prime and emergency standby generators, and with both on-road and off-road 

engines. In general, a DPF consists of a porous substrate that permits the gases 
E - 2

in the exhaust to pass through but traps the diesel PM. DPFs can reduce diesel 

PM emissions by more than 85 percent. The magnitude of these emission 

reductions depends on the baseline emissions of the associated engine, and the 

fuel sulfur content. In addition, up to a 90 percent reduction in carbon monoxide 

(CO) and a 95 percent reduction in hydrocarbons (HC) can also be realized with 

DPFs. (Allansson, 2000) Most DPFs employ some means to periodically 

regenerate the filter, i.e., burn off the accumulated PM. In California, dieselfueled school buses, emergency backup generators, solid waste collection 

vehicles, urban transit buses, medium-duty delivery vehicles, people movers, and 

fuel tanker trucks have been retrofitted with DPFs. These installations have been 

implemented through a number of voluntary and regulatory mandated programs 

as well as demonstration programs. DPFs can be either active or passive 

systems. 

Active DPFs use a source of energy beyond the heat in the exhaust stream to

induce regeneration. Active DPF systems can be regenerated with electric 

currents passed through the substrate, fuel burners, microwaves, or the aid of 

additional fuel injection to increase exhaust gas temperature. Some active DPFs 

induce regeneration automatically onboard the vehicle or equipment when a 

specified exhaust back pressure is reached. Others simply indicate when to start 

the regeneration process. Other active systems collect and store diesel PM over 

the course of a full day or work shift and are regenerated at the end of the day or 

shift when the vehicle or equipment is shut off. A number of the smaller filters 

are then removed and regenerated externally at a "regeneration station." 

Because active systems have control over their regeneration and are not 

dependent on the heat in the exhaust, active DPFs have a much broader range 

of applications and a much lower probability of getting plugged than passive 

DPFs. 

A passive DPF is one in which a catalytic material is applied to the substrate. 

The catalysts that are used are known as the platinum group metals. These 

consist of platinum, iridium, osmium, palladium, rhodium, and ruthenium. 

Platinum is best suited as the catalyst for diesel engine control devices; 

therefore, it appears that it will be the main catalyst used in diesel catalytic 

converters. (Kendall, 2002/2003) The catalyst lowers the temperature at which 

trapped PM will oxidize to a temperature periodically reached in diesel exhaust. 

No additional source of energy is required for regeneration, hence the term 

"passive."

Field experience has indicated that the success or failure of a passive DPF is 

primarily determined by the exhaust temperature profile at the filter's inlet and the 

rate of PM generated by the engine. These two parameters, however, are 

determined by a host of factors pertaining to both the details of the application, 

the duty cycle, the level of engine maintenance, and the type of engine being

used. As a result, the technical information that is readily accessible can serve 
E - 3

as a guide, but it may be insufficient to determine whether a passive DPF will be 

successful in a given application. (ARB, 2002)

With regard to estimating average exhaust temperature in actual use, commonly 

documented engine characteristics such as the exhaust temperature at peak 

power and peak torque are insufficient. The exhaust temperature at the DPF's 

inlet is highly application dependent in that the particular duty cycle experienced 

plays a prominent role, as does heat loss in the exhaust system. Various 

application-specific characteristics enter the heat loss equation, such as the 

length of piping the exhaust must travel through before it reaches the DPF and 

whether the exhaust is wet cooled or dry cooled. Lower average exhaust 

temperatures can also be the result of operations of engines oversized for the 

application or engines run with low or no load applied. (ARB, 2002)

Diesel Oxidation Catalysts

DOCs are currently the most commonly used form of diesel after-treatment

technology and have been used for compliance with the PM standards for some 

on-highway engines since the early 1990s. DOCs are generally referred to as 

“catalytic converters.” DOCs are attached to the engine exhaust system. They 

have chemicals lining them which catalyze the oxidation of carbonaceous 

pollutants – some of the soot emissions and a significant portion of the soluble 

organic fraction. These carbon-containing pollutants are oxidized to carbon 

dioxide (CO2) and water.

DOC effectiveness in reducing PM emissions is normally limited to about 30 

percent of diesel PM. This is because DOCs only control the soluble organic 

fraction (SOF) of diesel PM for modern diesel engines and the SOF fraction is 

typically less than 30 percent of total PM. Additionally, DOCs increase sulfate 

PM emissions by oxidizing the sulfur in fuel and lubricating oil, reducing the 

overall effectiveness of the catalyst. Limiting fuel sulfur levels to 15 ppm allows 

DOCs to be designed for maximum effectiveness (nearly 100 percent control of 

SOF emissions). DOCs also reduce emissions of HC and CO with reported 

efficiencies of 76 percent and 47 percent respectively. (Khair, 1999) 

DOCs are also very effective at reducing the air toxic emissions from diesel 

engines. Test data shows that emissions of toxics such as polycyclic aromatic 

hydrocarbons can be reduced by more than 80 percent with a DOC. (DieselNet, 

2002)

Flow Through Filters

Flow through filter (FTF) technology is a relatively new technology for reducing 

diesel PM emissions. Unlike a DPF, in which only gasses can pass through the 

substrate, the FTF does not physically "trap" and accumulate PM. Instead, 

exhaust flows through a medium (such as wire mesh) that has a high density of 
E - 4

torturous flow channels, thus giving rise to turbulent flow conditions. The 

medium is typically treated with an oxidizing catalyst or used in conjunction with a 

fuel-borne catalyst. FTFs reduce emissions of PM, HC, and CO. Any particles 

that are not oxidized by the FTF flow out with the rest of the exhaust and do not 

accumulate. 

The filtration efficiency of an FTF is lower than that of a DPF, but higher than a 

DOC. In addition, compared to DPFs, the FTF is much less likely to plug under 

unfavorable conditions such as high PM emissions, low exhaust temperatures 

and emergency circumstances. The FTF, therefore, is a candidate for use in 

applications that are unsuitable for DPFs. 

Combinations of Technologies

Combinations of more than one technology are also being explored to maximize 

the amount of diesel PM reduction. For example, fuel-borne catalysts can be 

combined with any of the three main hardware technologies discussed above: 

DPF, FTF, or DOC. 

NOx Emission Controls

There are various technologies available and in development to provide 

reductions in NOx. The principal technologies are selective catalytic reduction 

(SCR), water injection, exhaust gas recirculation, NOx adsorbers, and lean NOx

catalysts. These are each briefly described below.

Selective Catalytic Reduction

SCR is an exhaust after-treatment method for controlling NOx emissions up to 90 

percent. The SCR process basically works by injecting ammonia (NH3) or urea

into the exhaust gas or the engine in the presence of a catalyst. Ammonia 

reduces NOx in the presence of the catalyst to produce nitrogen (N2) and water. 

SCR systems have been installed on new marine engines for many years. 

However, retrofitting SCR systems on existing vessels is challenging. 

Challenging issues include urea and ammonia storage, safety requirements, and

space requirements near the engine. The SCR system is effective only over a 

narrow range of exhaust temperatures where the catalyst is active. Ammonia 

slip can also be a problem if the system is not properly optimized.

(DieselNet, 2006a) Ammonia slip is caused by injecting more ammonia into the 

exhaust stream than is needed to reduce the NOx. 

Water Injection

Adding water to the combustion chamber absorbs heat when the water 

vaporizes, lowering the peak combustion temperatures and reducing NOx
E - 5

emissions. Water can be introduced in a variety of ways: direct water injection,

fumigation into the intake air, or emulsified with the fuel. Unmodified engines can 

use emulsified fuel if the injection systems can handle the extra volume. Other 

systems require major redesign to include separate water supply tanks, injection 

lines, fuel pumps, injectors, etc. Generally, a 1 percent increase in water 

equates to a 1 percent decrease in NOx emissions. However, HC and CO 

emissions may increase using water injection strategies. (DieselNet, 2006)

Exhaust Gas Recirculation

Exhaust gas recirculation (EGR) lowers combustion temperatures thereby 

reducing NOx formation. EGR displaces some of the engine’s intake air with 

inert materials, which dilute the mixture in the cylinder and absorb heat. PM in 

the exhaust has the potential to be a source of problems with EGR, including 

accelerated wear in the engine and turbocharger and deposition on the engine 

intake system, which can decrease the effectiveness of the turbocharger and/or 

aftercooler. By reducing combustion temperatures and available air for 

combustion, EGR may cause incomplete combustion, increases in HC, CO, and

PM emissions, and decrease fuel economy. (DieselNet, 2006)

NOx Adsorber

NOx adsorbers utilize materials which store NOx under engine lean conditions,

then release and catalytically reduce the stored NOx under engine rich 

conditions. 

The process entails oxidation of NO to NO2, usually using a platinum-based 

catalyst, then oxidizing it again and storing it as a metallic nitrate on the catalyst 

surface. The most common storage component is barium carbonate (BaCO3), 

which can store NO2 as barium nitrate (Ba(NO3)2) while releasing CO2. 

The NOx adsorber is regenerated by operating for a brief period in an engine rich 

condition. NOx is released and subsequently reduced by precious metal 

catalysts just as a three-way catalyst does today on modern automobiles. NOx

reductions can be in excess of 90 percent if the catalyst is well matched to the 

exhaust temperature profile. (EPA, 2004) 

There are also diesel fuel reformers available that regenerate and desulfinate the 

NOx adsorption catalyst. The process consists of an electrically generated 

plasma and a noble metal catalyst that converts a diesel/air mixture into a 

hydrogen rich gas. Based on the partial oxidation process, carbon atoms from 

the fuel are oxidized to CO and the hydrogen is released as hydrogen molecules. 

This hydrogen rich diesel reformate provides a reducing atmosphere, improves 

NOx adsorption and catalyst regeneration, reduces the temperature at which 

desulfation occurs, and reduces the fuel penalty. (Bromberg, 2003)
E - 6

Lean NOx Catalyst

Lean NOx catalysts reduce nitrogen oxides through selective catalytic reaction 

with hydrocarbons. NOx conversion is usually limited to about 10-20 percent due 

to the relatively low concentrations of hydrocarbons in diesel exhaust. In active 

lean NOx catalysts, where diesel fuel is injected upstream of the catalyst, NOx

conversions of up to 50-60 percent are possible. Conversion rates are 

dependent on exhaust temperatures. (DieselNet, 2006a)

Engine Design Modification

There are a number of engine modifications that can be employed, generally at 

the time of an engine rebuild, to reduce emissions. Two examples of engine 

design modifications that reduce PM emissions are a diesel engine reengineering 

kit produced by Clean Cam Technology (Clean Cam) and the ECOTIP 

Superstack Fuel Injectors (ECOTIP) distributed by Interstate Diesel. 

Clean Cam consists of specific engine retrofit components, including a 

proprietary camshaft. The product reduces NOx emissions by increasing the 

volume of exhaust gas that remains in the combustion chamber after the power 

stroke. Within the combustion chamber, the residual exhaust gas absorbs heat 

and reduces the peak combustion temperature, which results in lower NOx

emissions. The injection timing can then be adjusted (i.e., advanced) to 

maximize the diesel PM emission reductions or it can be varied to achieve the 

desired balance of NOx and PM. The Clean Cam reduced diesel PM and NOx

emissions from eleven pre-1993 and four 1994-2000 models of two-stroke dieselfueled engines manufactured by Detroit Diesel Corporation (DDC). The ARB has 

pre-certified Clean Cam technology. Clean Cam’s Version 2 of the camshaft kit 

can reduce NOx emissions up to 10 percent beyond the U.S. EPA’s Tier 2 

Off-road engine NOx emission standards and can reduce PM emissions by 

75 percent beyond the U.S. EPA’s Tier 2 Off-road engine PM emission 

standards, depending on the engine’s horsepower rating.

Interstate Diesel takes a different approach with the ECOTIP Superstack Fuel 

Injectors to reduce emissions from existing engines. This product has been 

shown to reduce diesel PM emissions from engines manufactured by

Electro-Motive Division (EMD). The product consists of a fuel injector with a 

reduced sac [DEFINE SAC] volume and a more consistent fuel injection 

pressure, compared to average engines. The product improves combustion and 

reduces diesel PM emissions by minimizing the amount of fuel that drips into the 

combustion chamber at the end of the fuel injection cycle. The ECOTIP fuel 

injectors can provide a 2 to 3 percent fuel savings, depending on engine load. 

The manufacturer states that the overall diesel PM emission reduction can be up 

to 44 percent. The product is commercially available and has been installed on 

diesel generator plants, locomotives, and tugboats. (Interstate Diesel, 2006)
E - 7

Injection timing retardation

Retarding the injection timing has been used for decades for reducing NOx. The 

effect of injection retardation is to reduce the maximum combustion pressure and 

hence temperature. A reduction of up to 30 percent can be achieved by this 

technique however, a penalty of up to 5 percent in standard fuel consumption 

results, as the engine efficiency is reduced. Increase in injection pressure is 

used in conjunction with injection timing retard to maintain fuel consumption. 

Another modification that is used when implementing this strategy is a 

modification of the engine’s compression ratio.

Cleaner Diesel Fuels, Alternative Diesel Fuels, and Alternative Fuels

Diesel PM emission reductions can also be achieved through the use of cleaner 

diesel fuels, alternative diesel fuels, or alternative fuels (e.g., compressed natural 

gas). Some marine vessel owner/operators have explored the use of alternative 

diesel-fuels with some success and others have tried using compressed natural 

gas, however, there are some limitations when using alternative diesel fuels and 

alternative fuels. Below we describe some fuel options for marine engines.

Alternative Diesel Fuels

Alternative diesel fuel can be used in a diesel engine without requiring engine or 

fuel system modifications for the engine to operate, although minor modifications 

(e.g., recalibration of the engine fuel control) may enhance performance. 

Examples of alternative diesel fuels include biodiesel, emulsified fuels, FischerTropsch fuels, or a blend of these fuels with CARB diesel fuel. A detailed 

discussion of these fuels is provided in the Diesel Risk Reduction Plan. (ARB, 

2000) These alternatives may result in significant benefits for higher-emitting 

applications. Synthetic or alternative diesel fuels may also prove to be part of the 

preferred control strategy for diesel-fueled engines that would otherwise expose 

people to relatively high risk, or where control retrofit options are very expensive 

or difficult to implement. The impacts these fuels can have on emissions from 

diesel-fueled engines can vary. There has not been significant penetration of 

these fuels into commercial marine engine applications, however biodiesel is 

being used with some success in some ferries and recreational boats. (von 

Wedel, 1999; Biodiesel.org, 2006) 

Alternative Fuels

Alternative fuels may be an option to reduce emissions from diesel engines, but 

use of these fuels in marine applications is not as prevalent as in land-based 

applications. Use of alternative fuels in marine vessels presents a variety of 

safety issues that the U.S. Coast Guard must address before vessels can be 

converted such they can use alternative fuels. The passenger ferry James C. 

Echols in Norfolk, Virginia was converted from diesel to compressed natural gas
E - 8

(CNG) fueled twin Caterpillar 3406_G natural gas engines in 1995 and was 

emissions tested in 2002. The natural gas engines ran richer than optimum, and 

adjustments to the fuel-air ratio resulted in a reduction in power. (Wilcox, 2000; 

Thompson, 2002) The concept of using vent gas from the boil-off of liquefied 

natural gas (LNG) carriers to fuel propulsion and auxiliary engines has been 

employed in a Gulf Coast shrimp boat by converting the engines to use CNG. 

LNG is bunkered and converted to CNG fuel through boil-off before use. 

(Wilcox,-2000; Acker, 1989)

Repowering

Repowering (i.e., replacing the engine) can be a viable and cost-effective way to 

reduce emissions when compared to the older, uncontrolled diesel engines they 

replace. Heavy-duty diesel engines currently being manufactured are 

significantly cleaner than those built just a short time ago and can provide 

significant NOx and PM benefits compared to an older engine. (Diesel, 2002a)

The Carl Moyer Memorial Air Quality Standards Attainment Program 

Repowering harbor craft has been on-going throughout the state under the 

auspices of California’s Carl Moyer Memorial Air Quality Standards Attainment 

Program (Moyer) for eight years. As of fiscal year 2003-2004, more than 450 

engines have been replaced in approximately 300 harbor craft. The types of 

vessels that have participated in Moyer are representative of all types of harbor 

craft; ferries and excursion vessels, tugboats, towboats, commercial fishing 

vessels, charter fishing vessels, and others.

Moyer provides funds for the incremental cost of cleaner-than-required engines 

and equipment which result in significant near-term reductions in NOxand PM 

emissions. Marine vessel repowers in Moyer are required to achieve a minimum 

of a 15 percent reduction in NOx emissions to be eligible for funding. The 

average engine replacement cost was approximately $100,000 and the average 

Moyer contribution per engine was approximately $54,000. Emission reductions 

from marine vessels achieved through Moyer in the first seven years totaled 

1,250 tons per year of NOx and 75 tons per year of PM at a NOx-weighted 

average cost effectiveness of $1,800 per ton. (ARB, 2006)

Fuel Cells

Fuel cells have captured worldwide attention as a clean power source and have 

generated interest and enthusiasm among industry, enviromentalists, and 

consumers. In principle, a fuel cell operates like a battery. A fuel cell converts 

chemical energy directly into electricity by combining oxygen from the air with 

hydrogen gas. However, unlike a battery, a fuel cell does not run down or 

require recharging. It will produce electricity as long as fuel, in the form of 
E - 9

hydrogen, is supplied. Fuel cells have been a reliable power source for many 

years.

There have been some limited applications of fuel cell technologies on marine 

vessels. Fuel cells on marine vessels have operated for several years as an 

auxiliary power source. In the summer of 2002, adventurer Kenichi Horie sailed 

Malt’s Mermaid III across the Pacific Ocean and derived on-board electricity from 

a 30-watt direct methanol fuel cell made by Yuasa. In November 2002, a 

300 watt fuel cell provided auxiliary power for the Branec III in the Route du 

Rhum yacht race across the Atlantic Ocean from France to Mexico. (Cropper, 

2004)

In October 2003, MTU Friedrichshafen and Ballard Power Systems built a 

12 meter yacht propelled by a 20 kilowatt (kW) battery/fuel cell system. The 

compressed hydrogen fuelled yacht has a range of 225 kilometers (km) at 

6 kilometers per hour (km/hr) or 25 km at 12 km/hr. (Cropper, 2004)

Also in 2003, a 30-foot, 22 passenger, 6 kW Anuvu fuel cell-powered Duffy 

Electric Boat, Inc.’s DH30 water taxi was test run in Newport Harbor. The fuel 

cell extended the operating time of the 15 kW electric motor launch by 6 hours at 

about 5.5 miles per hour. Aqueous sodium borohydrate (15 percent by weight) 

was used to generate saturated hydrogen, which does not degrade the proton 

exchange membrane. The byproducts are water and borate, which is returned to 

the manufacturer to be reprocessed to sodium borohydrate. The sodium 

borohydrate was manufactured by a pharmaceutical company and was 

expensive. The project was not economically viable, but it demonstrated a fuel 

cell boat could function. (Seaworthy, 2003; CCDoTT, 2003; Seaworthy, 2006)

The San Francisco Bay Area Water Transit Authority (WTA) has plans to build a

vessel with a fuel cell-powered auxiliary engine as one element of an EcoFriendly Power System. That vessel is still in the planning stages. (WTA, 2003)

In-Use Experience with Diesel PM and NOx Emission Control Strategies on 

Harbor Craft

Demonstration Projects:

There have been a number of demonstration projects nationwide funded 

primarily through public agencies to implement installation of aftermarket 

emission controls for harbor craft. The alternative emission control strategies 

used in these demonstration projects represent the range of choices a harbor 

craft owner/operator has when deciding whether to use an after-treatment 

devices to reduce emissions from their vessel. Brief discussions of some of 

these demonstration projects are presented below.
E - 10

Diesel Particulate Filters

U.S. Navy Workboat

In 2006, one of two early 1970’s two-stroke Detroit Diesel Corporation (DDC)

12V-71 400 horsepower engines on a U.S. Navy workboat operating in the 

Suisun Bay was rebuilt. The port engine was rebuilt with Clean Cam Technology 

System (CCTS), The CCTS engine rebuild replaces the original cam shaft, 

updates the cylinder liner configuration, and adds a turbocharger to the engine. 

This rebuild kit is made to reduce NOx and PM emissions from a variety of DDC 

engines during the normal rebuild cycle. 

In addition to the engine rebuild, a Rypos active diesel particulate filter replaced 

the traditional exhaust muffler. The Rypos diesel particulate filter (DPF) consists 

of a filter housing, electrical control circuit, and filter cartridges. The Rypos 

system does not rely on high exhaust gas temperatures for filter regeneration;

instead a controller monitors pressure, initiating regeneration when needed. The 

filters are made of sintered metal, which can be heated electrically for filter 

regeneration.

The preliminary emissions tests results for each diesel emission control strategy 

and combined are as follows. The rebuilt CCTS engine reduced PM emissions 

by over 30 percent and NOx by approximately 70 percent. The Rypos filter 

achieved a reduction of PM of approximately 70 percent and a small reduction of 

NOx. Used together, the CCTS and Rypos active DPF achieved over 80 percent 

reduction of PM and over 70 percent reduction of NOx. Durability testing of the 

system was completed in late 2006. To date, we have not received the results of 

those tests.

Selective Catalytic Reduction

Vallejo Ferry

In 2004, the City of Vallejo, California, launched the M/V Solano, a low emissions 

ferry utilizing urea-based selective catalytic reduction (SCR) made by Steuler 

GmBH. This ferry is part of the Vallejo Baylink passenger ferry system, which 

services Vallejo and the North San Francisco Bay. The ferry has two MTU/DDC 

16V-4000 engines with rated power of 3100 hp each. The SCR system is 

designed to reduce NOx by 57 percent. (Baylink, 2006; MARAD, 2003)

In July of 2007, BayLink was experiencing an increase in engine problem alarms. 

BayLink staff inspected the engines and the SCR unit. They found that a number 

of the engines in the starboard unit were showing excessive wear. They also 

examined the starboard SCR unit and found extensive damage. The damage to 

the SCR unit included corrosion, heat impacts, and mechanical impacts. The 
E - 11

BayLink staff have published a report and continue to look into the potential 

reasons for the damage to the engine and the SCR unit. (BayLink, 2007) 

Staten Island Ferry

Staten Island Ferry (M/V Alice Austen) was retrofitted with selective catalytic 

reduction and a diesel oxidation catalyst in 2004. The ferry is propelled by two 

Caterpillar 3516 1,550 horsepower main engines. The system reduces NOx by 

50 percent as well as PM by 25 percent. With adjustments to temperature 

thresholds and one of the main engines rebuilt, the anticipated NOx reduction is 

about 70 percent. (Bradley, 2006)

The Alice Austen has been operating with SCR since 2005. The vessel is in 

service during the night runs of the Staten Island Ferry system (9 p.m. to 5 a.m.). 

A complete circuit of the route the vessel is assigned to takes about an hour. 

The vessel idles for about 15 minutes during passenger off- and on-loading, 

makes a twenty minute run to the route’s destination, idles for 15 minutes to offload and on-load passengers, and makes a twenty minute run back to its point of 

origin. To date, there have been no problems with the SCR system.

San Francisco Bay Area Water Transit Authority (WTA) Ferry

WTA is planning to build two new 149 passenger ferries to be put into service in 

late 2008 which will include exhaust aftertreatment to reduce NOx emissions by 

at least 85 percent beyond Tier 2 standards. The ferries are being designed to 

incorporate a compact SCR system coupled with an oxidation catalyst with the 

1410 hp Detroit Diesel propulsion engines. The inclusion of the aftertreatment 

system will require about six feet to be added to the vessel’s overall length. The 

system was derived from one that has been used on other mobile equipment. 

The ferries’ design includes a dry exhaust with a high exhaust stack. 

(WTA, 2006)

Hybrid Systems 

Foss Tugboat

The Foss Tug Company of Seattle, Washington recently “laid keel” on a Dolphin 

class hybrid tugboat. The tugboat will be a stern drive vessel used primarily for 

harbor assist services. The tugboat’s electric drive units will be powered by 

batteries coupled with diesel-fueled generators. The vessel’s engine room will be 

modified to accommodate two 670 horsepower battery packs and two 335 

horsepower generators. Although the main engines will have lower horsepower 

than those found in the existing Dolphin class tugboats (5000 hp), the total 

horsepower of the hybrid tugboat will be equal to that of the existing Dolphin 

class tugboats.
E - 12

Foss anticipates a number of benefits from the use of hybrid technology. These 

benefits include over a 40 percent reduction in emissions of PM and NOx, lower 

fuel consumption, and a reduction in the noise associated with the operation of 

the vessel. It is anticipated that the vessel will begin operations in 2008. 

Humid Air Injection

SCX Ferries, Inc and MARAD tested the emission reduction potential of an air 

humidification system on a hydrofoil ferry, WaveRider, in San Diego, California. 

The ferry is powered by four high-speed Detroit Diesel 12V92 engines, each 

rated at 1050 hp at 2300 rpm, driving two water jets. They installed a water 

injection (fumigation) system to reduce NOx by reducing peak combustion 

temperatures. The system was able to reduce NOx by about 16 percent.

(MARAD, 2003)
E - 13

References

(Acker, 1989) Acker, G. Jr., et al. “Experience Using LNG as a Marine Engine 

Fuel.” Marine Technology Society Journal. Vol. 23, No. 2, 33-39; 1989.

(Allansson, 2000) - DPF

(ARB, 2002) California Air Resources Board. Staff Report: Initial Statement of 

Reasons Proposed Regulation for Verification Procedure for In-Use Strategies to 

Control emissions from Diesel Engines, Appendix B, Diesel Emission Control 

Technologies; 2002.

(ARB, 2006) Joseph Calavita, California Air Resources Board. Personal 

communication. October 5-6, 2006.

(Baylink, 2006) Martin Robbins, Baylink Ferry. Personal communication. 

October 24, 2006. [ print e-mail]

(Baylink, 2007) SCR Project-M/V Solano, June 30, 2007.

(Biodiesel.org, 2006) “Easier on the Marine Environment.” biodiesel.org 

http://www.biodiesel.org/markets/mar/ Date accessed: November 1, 2006.

(Bradley, 2006) M.J. Bradley and Associates. Staten Island Ferry: Alice Austen 

Vessel SCR Demonstration Project Final Report. August 2006.

(Bromberg 2003) Bromberg, L., et al. “Hydrogen generation from plasmatron 

reformers: A promising technology for NOx adsorber regeneration and other 

automotive applications.” Diesel Engine Emission Reduction Workshop. 

Newport, RI Aug 24-28, 2003.

(CCDoTT, 2003) Center for the Commercial Deployment of Transportation 

Technologies, California State University, Long Beach Foundation. “On Demand 

Hydrogen Generating System: Phase II—System Demonstration.” September 

30, 2003. 

ftp://www.foundation.csulb.edu/CCDoTT/Deliverables/2002/task%202.25/task_2.

25_6_FY02.pdf Date accessed: November 1, 2006.

(Cropper, 2004) Cropper, Mark. “Fuel cells in ocean-going yachts.” Fuel Cell 

Today. March 5, 2004.

http://me.queensu.ca/courses/MECH430/Assets/Files/General%20Interest/Fuel%

20Cells%20In%20Yachts%20March%202004.pdf Date accessed October 25, 

2006.

(DieselNet, 2002) DieselNet. Technology Guide: Diesel Oxidation Catalyst. 

http://www.dieselnet.com; 2002.
E - 14

(DieselNet, 2002a) DieselNet. http://dieselnet.com/tech/engine_adv.html

(DieselNet, 2006) DieselNet. DieselNet Technology Guide. Engine Design for 

Low Emissions: Water in Diesel Combustion. 

http://www.dieselnet.com/tech/engine_water.html; September 29, 2006.

(DieselNet, 2006a) DieselNet, DieselNet Technology Guide. Diesel Emission 

Control. http://www.dieselnet.com/tech/engine_control.html; September 29, 

2006.

(EPA, 2004) EPA, Final Regulatory Analysis: Control of Emissions from Nonroad 

Diesel Engines Chapter 4; May, 2004. EPA420-R-04-007

(Interstate Diesel, 2006) Lee Arkus, Interstate Diesel – McBee. Personal 

Communication. October 20, 2006.

(Kendall, 2002/2003) Kendall, Tom; Johnson Matthey. Platinum 2002 

http://www.platinum.matthey.com/publications/1051543656.html; Platinum 2003, 

http://www.platinum.matthey.com/publications/1059138410.html; May 2002 and 

May 2003.

(Khair, 1999) Khair, Magdi, Dale L. McKinnon Performance Evaluation of 

Advanced Emission Control Technologies for Diesel Heavy-Duty Engines, SAE 

1999-01-3564; 1999.

(MARAD, 2003) U.S. Department of Transportation Maritime Administration 

Office of Shipbuilding and Marine Technology. Energy Technologies. Newsletter 

No. 04; Winter 2003-2004. 

http://www.marad.dot.gov/nmrec/energy_technologies/images/ETNo4Winter0304

.htm August 9, 2006.

(Seaworthy, 2003) “Fuel Cell Boat Tested in Newport, California Harbor; 

Millennium Cell, Seaworthy, Duffy Boat and Anuvu Demonstration Takes to the 

Water.” Business Wire. August 21, 2003. 

(Seaworthy, 2006) Marty Toyen. Seaworthy Systems. Personal communication. 

October 27, 2006.

(Thompson, 2002) Thompson, Gregory J., et al. “Evaluation of Exhaust 

Emissions from Elizabeth River Ferries: Final Report.” Department of 

Mechanical and Aerospace Engineering, West Virginia University. Morgantown, 

WV July 2002. http://cafee.wvu.edu/Assets/Documents/Report%20-

%20Evaluation%20of%20Exhaust%20Emissions%20from%20Elizabeth%20Rive

r%20Ferries.pdf Date accessed: October 26, 2006.
E - 15

(von Wedel, 1999) von Wedel, Randall. Technical Handbook for Marine 

Biodiesel in Recreational Boats. Second Ed. April 22, 1999. 

www.cytoculture.com/Biodiesel%20Handbook.htm Date accessed: August 24, 

2006.

(Wilcox, 2000) LT Robb Wilcox, CDR Mark Burrows, Sujit Ghosh, Bilal M. 

Ayyub. “Risk-based Technology Methodology for the Safety Assessment of 

Marine Compressed Natural Gas Fuel Systems.” International Cooperation on 

Marine Engineering Systems/The Society of Naval Architects and Marine 

Engineers. New York Metropolitan Section Symposium May 22-23, 2000. 

http://www.uscg.mil/HQ/msc/article/cng.paper.pdf Date accessed: October 26, 

2006.

(WTA, 2003) San Francisco Bay Area Water Transit Authority. “Congress Floats 

Fuel Cell Boat with $2.5 Million.” Press Release. February 20, 2003. 

http://www.watertransit.org/pubs/FuelCellBoat.pdf October 18, 2006.

(WTA, 2006) San Francisco Bay Area Water Transit Authority. “The SF Bay 

Area Water Transit Authority is Building Boats.” Press Release. May 9, 2006. 

http://www.watertransit.org/pressreleases/pressRelease050906.pdf

October 18, 2006.