Aftermarket Retrofit Technologies

Aftermarket retrofits incorporate new cleaner burning technologies and apply
them to existing engines. These technologies are an “add-on” feature designed to reduce
emissions levels. They replace, remove, and/or add an additional component to an
existing engine.



Injection Timing Delay-decreases NOx emissions by retarding the amount of
diesel fuel delivered to the combustion chamber prior to compressed ignition. Due to the
decrease in fuel delivered to the combustion chamber, combustion temperatures are
lowered, decreasing associated NOx levels. However, due to the inefficient fuel delivery
scheme that this technology applies, two negative side effects are created: power levels
are decreased, while PM vented to atmosphere actually increases.



Water Injection-introduces a supply of water into the diesel engine’s fuel delivery
mist. This water injection decreases the combustion temperature, and thus reduces NOx
emissions to atmosphere. However, successful field testing has been limited to only one
engine type, Wartsila. This technology also requires increased on-board storage space
and the associated weight increases necessary for water storage. End users in the marine
environment are critically sensitive to decreased storage space and increased weight
burden requirements.



Selective Catalytic Reduction (SCR)- incorporates a reducing agent (ammonia or
urea) into the exhaust stream, following the combustion process. While the spent exhaust
fumes pass through the SCR, the reducing agent breaks NOx emissions down into benign
sub-components. This technology has been successfully employed in land-based
stationary power plants resulting in large (90-99%) decreases in NOx emissions.
However, marine field testing is limited, and estimated purchase, installation, and
operation costs are projected to be very high. Due to limited data available in successful
marine applications, land based costing data has been utilized in this analysis for
estimation purposes. For our analysis, we have applied the land based average cost of
$71/kw for SCR purchase and installation. The Munters Company of Europe, based in
Sweden, has recently been awarded a contract to supply SCRs to four marine tanker
vessels, scheduled to be delivered in 2006-7. These units will be the first SCRs installed
on commercial cargo vessels. Munters is hoping to achieve 85-99% NOx reductions.
Viking Cruise Lines has also employed this diesel emissions-reducing technology on its
cruise ship Viking Cinderella since September, 2003. This vessel boasts the cleanest onboard
cruise ship emissions in the industry at less than .4 g/kw-hr NOx content.25


Shore Power-involves temporarily replacing a marine vessel’s power generation
capacity with a shore-side alternative. This process “cold stacks” the auxiliary engines
onboard a marine vessel while the vessel rests at berth, and allows hotel power
requirements to be served by land-based generation equipment. The technology has been
field tested and implemented successfully in both military and cruise ship applications.
Although the technology enables a vessel to effectively reduce all at-berth emissions by
100%, it is very costly to implement. Both capital-intensive shore-side and on-vessel
modifications are required in order to supply vessel electricity requirements from a landbased
power generation source. Since shore-side plants are placed under more stringent
EPA emission regulations than marine counterparts, total emission levels are reduced
when using shore side power. If the replacement power generation source is based upon a
renewable resource such as hydro power, these levels are further reduced. However, this
application seems currently applicable only to the cruise ship sector, based on their large
hotel power requirements, and primary US territorial operations