Emission Controls on Ships
06-02, 2014
Emission Controls on Ships
1. INTRODUCTION
In 1992, there were roughly about 1.291 million containers in the Port of Oakland and by 2006 it had increased by about 185% to about 2.391 million containers. With such sizable increases the effects have been seen in the local and national economics but one area that has been overlooked is the increased amounts of pollution. Here is a proposal on how to reduce pollution in the Port of Oakland while minimizing the effect in the increased number of ships coming into the Port of Oakland. Provided below is a graph of the number of containers for each year from 1992 to 2006.
Some history on the Port of Oakland, the Port began to admit container ships back in 1962. Container traffic has greatly increased the amount of cargo loaded and unloaded in the Port of Oakland. By the late 1960s, the Port of Oakland was the second largest port in the world in container tonnage. However, depth and navigation restrictions in San Francisco Bay limited its capacity. By the late 1970s it had been supplanted by the Ports of Los Angeles and Long Beach as the major container port on the West Coast.
In the Port of Oakland presently there are many ships equipped with large engines running on bunker fuel without emission controls, thousands of diesel trucks per day, diesel locomotives, and other polluting equipment. These activities at the Port of Oakland cause an array of environmental impacts that have seriously affect the local communities, marine, and land-based ecosystems throughout the region. Some of the impacts seen from the Port are an increased risk of cancer in nearby communities, increased regional smog, contamination of water, the introduction of destructive foreign species, aesthetic effects on local communities, and public lands (Bailey & Solomon, 2004).
The focus of this proposal is on the range of options available to move towards a greener seaport in Oakland. One thing to realize with any polluting industry, there are many ways to mitigate and eliminate health impacts though they heavily rely on the consideration of the public health, feasibility, and cost. For the Port of Oakland, the measures range from possible changes to idling limits for trucks, sweeping global changes in the international trade. The major reason for this proposal is because the Port of Oakland like many other ports throughout the world is complex pollution sources. Also like many other on-site processes there is not one single solution to solve all the problems. The best approach to take is to define the alternatives that can make significant improvements in the air quality, and to set goals for the best environmental practices that are stringent, but yet still achievable.
2. SOURCES OF AIR POLLUTION AT PORTS
Sea ports are a major source of air pollutants that affects the heath of people living in nearby communities, not to mention the problems that this can cause to regional air pollution. Major air pollutants include the following: diesel exhaust, particulate matter (PM), volatile organic compounds (VOCs), nitrogen oxides (NOx), ozone, and sulfur oxides (SOx). Air pollutants that come from the operation of the port include: carbon monoxide (CO), formaldehyde, heavy metals, dioxins, and pesticides used to fumigate produce.#p#分页标题#e#
Worldwide, marine vessels pour out about 14% of the NOx, and 5% of the SOx from all fossil fuel sources (2004). In 2000, commercial marine vessels accounted for roughly 7% of NOx and 6% of PM emissions from all mobile sources in the United States (2004). With an increasing number of imports these numbers are expected to rise. In 2004 the projections for 2007, large commercial ships were expected to emit 6-65 times more NOx per unit of engine power than diesel transit buses (2004). The US Environmental Protection Agency (EPA), is expecting the contributions of PM and NOx from marine vessels is double by the year 2020 (2004).
Presently the vast majority of on-land equipment currently in use at ports runs on diesel fuel. Cargo-handling equipment is classified as equipment that would be used to load and unload large cargo containers from ships, locomotives, and trucks. As well as shuttling those containers around for storage. Cargo-handling equipment includes gantry cranes, yard trucks, top-picks, side-picks, and forklifts. The gantry cranes are primarily used to load and unload ships, yard trucks are used in shuttling containers, and the others such as top-picks, side-picks, and forklifts perform jobs that are not listed above but required in running a port. Regulation of off-road equipment lags behind on-road trucks and buses by several decades. Emission standards for heavy diesel equipment emits about 15 times more PM and NOx that new highway trucks and buses.
3. EFFECTS ON HEALTH WITH AIR POLLUTION
Diesel exhaust is a mixture of particles, vapors, and gases emitted from the burning of diesel fuel. In addition to containing pollutants outlined above with their associated health impacts, diesel exhaust contains an estimated 450 different compounds, which about 40 of them are considered to be toxic air contaminants with negative effects on the health and the environment (2004). Studies of people exposed to diesel exhaust have reported some of the following eye and nose irritation, bronchitis, cough, phlegm, wheezing, and deterioration in lung function (2004). New scientific evidence suggests that diesel exhaust may have a casual role in the initiation of allergies and asthma.
Dozens of studies have shown that long-term exposure to diesel exhaust significantly increases the risk of lung cancer (2004). Some studies have also reported links between diesel exposure and other cancers, including bladder, kidney, stomach, multiple myeloma, leukemia, Hodgkin’s disease, non-Hodgkin’s lymphoma, and cancers of the oral cavity, pharynx, and larynx (2004).
Particulate matter (PM) pollution ranges from a coarse dust to very tiny sooty particles formed when gasoline or diesel is burned. It is the tiniest PM that can cause the greatest health concerns (2004). Dozens of studies link fine PM concentrations to increased hospital admissions for asthma attacks, chronic obstructive lung disease, bronchitis, pneumonia, heart disease, and premature deaths (2004).#p#分页标题#e#
Volatile organic compounds (VOCs) include a long list of chemicals used in industry, as well as chemicals emitted from motor vehicles such as diesel trucks and buses. VOCs are characterized by their ability to evaporate into the air and produce ozone smog and by their inherent toxicity (2004). Formaldehyde is very irritating to the airways, and is a probable carcinogen (2004). Toluene at occupational exposure levels has been associated with birth defects and miscarriages (2004). Other VOCs emitted by vehicles have also been linked to cancer, reproductive harm, asthma, or neurological disorders (2004).
Nitrogen oxides (NOx) have had numerous studies finding that it can cause toxic effects in the airways, leading to inflammation and to asthmatic reactions. In fact people with allergies or asthma have far stronger reactions to common allergens such as pollen when they have been exposed to NOx (2004).
Ozone, also known as ozone smog, is reactive gas produced when VOCs or NOx interact with the sunlight and split apart oxygen molecules in the air. Ozone can make people more susceptible to respiratory infections and can aggravate preexisting respiratory diseases, such as asthma (2004). Ozone can also cause irreversible changes to the lung structure, which eventually lead to chronic respiratory illness, such as emphysema and chronic bronchitis (2004).
Sulfur oxides (SOx) are produced from the burning of sulfur-containing fuels such as diesel and particularly high sulfur marine fuels, bunker fuel. These compounds include sulfur dioxide and a range of related chemical air pollutants. SOx reacts with water vapor in the air to create acidic aerosols that irritate the airways sometimes causing discomfort and coughing in healthy people, and often causing severe respiratory symptoms for asthmatics (2004).
Then lastly children are some of the most susceptible to air pollution because of their lungs are still in the developing and because their airways are narrower than those of adults. In addition, children often play outdoors during the day and thus may be more exposed. Children raised in heavily polluted areas have reduced lung capacity, prematurely aged lungs and increased risk of bronchitis and asthma compared to peers living in less polluted areas (2004).
4. SUGGESTED CONTROL MEAUSRES ON POLUTION AT THE PORT OF OAKLAND
Easily Achievable Approaches
Many ports around the world have adopted approaches that can significantly reduce their contribution to pollution to the surrounding areas. We hope in this proposal to show some of these and how they could benefit the Port of Oakland. Some of the measures that other places have done already that are easily achievable are to use cleaner fuels and enforcement of idling limits.
Cargo handling equipment and ships at the Port of Oakland currently run on a much dirtier fuel grade of diesel fuel that on-road diesel trucks. To put this in prospective, an ocean-going ship typically run on bunker oil, this is over 100 times the amount of sulfur than that of on-road diesel transportation (2004). Several cleaner fuel options are currently available and also compatible with the existing diesel engines. These include low sulfur diesel, diesel emulsions, biodiesel, Fischer-Tropsch diesel (2004). Note that low sulfur diesel is the most widely available and cheapest source to turn to but it does not provide nearly the same amount of reductions for certain pollutants (2004). See Table 2.#p#分页标题#e#
The intended use of low sulfur diesel is generally been intended to be used in the combination with emission controls, but it does not offer a substantial emission reduction even when used alone as a replacement fuel. Though as of 2003, the Port of Oakland has convinced most of its terminal operators to adopt low sulfur diesel for cargo handling equipment (2004).
Then in diesel emulsions, aqueous diesel, this can be used as an emissions reducer at ports also. There are presently three brands of aqueous diesel that have been verified by the California Air Resources Board (ARB) (2004). Although these only provide a slight decrease in NOx, some studies have shown that have shown significant decreases in PM with the use of this fuel (2004). Though note that on off-road equipment the results have not shown as impressive of results through studies (2004).
Another option is biodiesel, which is most commonly sold as a blend with 80% or more conventional diesel (2004). The emission benefits of these blends show a 10–20% improvement over regular diesel (2004). Pure biodiesel does offer more substantial PM and CO2 reductions—on the order of 50%—but at the expense of an increase in NOx, by as much as 10% (2004). However there are many engine manufacturers do not warrant their products for use with pure biodiesel, because it can cause corrosion in some engines. Biodiesel is distributed in many regions throughout the United States, though prices vary widely, as does the feedstock used to make biodiesel fuel, which can include used oils and grease, or farmed products such as corn. The biodegrade-ability of biodiesel makes it well suited for marine uses because spills are not a serious problem.
Lastly, Fischer–Tropsch diesel is usually made from coal, but is sometimes made from natural gas, leading to the recent acronym Gas to liquids (GTL) fuel (2004). Much of the Fischer–Tropsch diesel in the United States is imported from Malaysia. However, plans may be underway to build a full-scale
US plant soon (2004). Fischer–Tropsch fuel can reduce emissions of NOx by more than 10% and of several other pollutants in the range of 30% (2004). The costs and overall environmental benefits are contingent on transport and feedstock’s, and are not yet well known at the time of writing.
Another area that is under the category of easily achievable approaches is the use of idling limits. With having well-enforced idling restrictions the savings are amazing because one can save on hundreds of gallons of fuel per vehicle and not to mention that a cost effective way to substantially reduce diesel emissions from trucks and locomotives. The reason we can have idling limits in place for the trucks and locomotives is due to the fact that they normally tend to stand idle in the port for long periods of time.
The cost of idling restrictions would roughly be about US$800,000 per year to cover signage and additional personnel to monitor compliance, this yields in a cost ratio of roughly US$2000 per ton of NOx reduced, which is extremely cost competitive compared to other measures being considered (2004). Additionally, the cost estimates do not include other pollutants that are significantly reduced, such as PM and carbon dioxide. Finally, this measure saves millions of dollars in fuel costs as well as engine maintenance costs (2004). Note that in 2003 the state of California did implement an idling law for all trucks in ports in major metropolitan areas, like Oakland, to thirty minutes (2004). Though this is helpful there is perhaps more California can do on this measure.#p#分页标题#e#
Through this measure locomotives can also substantially reduce pollution through automatic idling control devices. Switching engines are currently used to move trains around within rail yards, are generally highly polluters and tend to idle about 75% of the time (2004). This makes them perfect candidates for automatic idling controls. These controls reduce fuel use, diesel emissions, and noise. The EPA estimates that 10% of all rail fuel could be saved, which translates to 366 million gallons and US$240 million (2004). Most automatic idling controls for locomotives cost roughly US$6000–US$10,000, with more elaborate devices costing up to US$40,000 (2004).
5. POLLUTION MEASURES THAT REQUIRE CAPITAL INVESTMENTS
One thing about pollution mitigation measures there are parts that do require infrastructure and also capital investments that are not covered. These changes can be used to further reduce their impacts on pollution. Some of the measures that would require investments include retrofit, repower, and retirement of vehicles, equipment, locomotives, and ships. Not to mention that there is the possibility of having equipment running on alternative fuels such as natural gas.
One area that has been lagging behind the modern emission standards are some of the oldest, most pollutant vehicles, equipment, and vessels that need to be replaced. In many cases, the exhaust systems can be retrofitted with emission controls, which can significantly reduce exhaust emissions. While replacement of older vehicles and equipment is often the most preferable solution, retrofits and repowers often tend to offer a more practical solution for existing fleet. Repowers are sometimes limited by the age and configuration of the vehicle or piece of equipment; however in most cases at least one control technology can be retrofitted to any vehicle or piece of equipment (2004).
Recently the Port of Oakland has begun a program to clean up yard equipment, funded through a settlement that the Port reached with the surrounding community over an expansion (2004). Terminal operators can use the funds of this voluntary program to retrofit, repower or make cleaner purchases of terminal equipment. The Port of Oakland plans also to start a similar program for offsite trucks visiting the port terminals, with the remaining settlement money (2004).
Another area that has high polluting is the switching locomotives that can actually be repowered with several low-emitting engine options. These options include natural gas and hybrid battery-electric. Several alternative fuel and hybrid-electric locomotives are in the market and are available for purchase. Some places have performed converting diesel locomotives to natural gas fuel. This option requires an overhauling of the engine and fueling system. The cost of this conversion is roughly US$400,000 to US$800,000 per locomotive (2004). In repowering these locomotives with the use of natural gas engines it shows roughly a reduction in NOx by 4.8 tons a year (2004). This solution can not be overlooked for the Port of Oakland because of the fact that natural gas infrastructure is in existence.#p#分页标题#e#
The other option for locomotives is a hybrid-electric switching locomotive which retails for US$750,000, which is roughly half the cost of a conventional locomotive. Not to mention that under this technology that the locomotive reduces both PM and NOx by 85% or 13.5 tons per year (2004).
The replacement of the locomotives would primarily concern themselves with the locomotives that were built before 1973 or the engines that have yet to meet federal standards providing the most significant emission benefits (2004). The switching locomotives are good candidates for repowers due to they are idle for such a long periods of time.
With the locomotives being a major part of the rail yards, the item that still needs to be discussed that is in the harbor is the tugboats. A staggering statistic states that the average tugboat in the San Francisco Bay Area found that the average age of the tugboat in service is 30 years or more (2004). These tugboats themselves contribute a big amount to the pollution because most of them have a two-cycle engine. Though one great thing about tugboats is they are great candidates for being repowered. The average cost of replacement can roughly cost around US$400,000 and yields in reduction in NOx by 73 tons per year (2004).
Alternative fuels for yard equipment is one last major area under consideration for pollution measures that require public investment. When looking to the equipment such as terminal tractors and other cargo handling equipment the type of fuel it uses propane and natural gas (NG) should be considered. The benefits of choosing these fuels as compared to diesel are very substantial when looking into reducing emissions. Switching to alternative fuels can completely eliminate emissions of diesel particulate matter (PM) and significantly reduces NOx emissions (2004). For example NG powered buses have demonstrated PM emissions are 20-100 times lower than its diesel counterpart (2004). Though natural gas engines do have significant lower NOx and PM they do possibly have higher CO and CO2 emissions and slightly higher hydrocarbon emissions (2004). Note that these increases can be considered minimal when seeing the amount of reduction in NOx and PM emissions that have been seen in natural gas.
6. FUTURE TECHNOLOGIES
One future technology is having emission controls on ships. Presently in Europe there is a lot of work being done to explore the emission control for ships. Selective Catalytic Reduction (SCR), a control technology that drastically reduces the smog-forming NOx coming from the smokestacks has been installed on over 100 large ships, mostly in the Baltic Sea area (2004). Though this technology still has several things to overcome, including cost, it could potentially shown as the most effective way to measure for mainstream use (2004).
Another area is looking into shore-side power for ships while they are at dock. Ships normally when they are docked they use diesel fueled auxiliary engines while docked to run systems such as lights, pumps, and fans. The engine can be set idling for many days at a time which can cause large amount of pollution not to mention the amount of noise this generates. Recently in 2001 the Port of Oakland has begun to install power plug-ins for tugboats (2004). This allowed the tugboats to shut down their engines while at dock. Though Oakland does considers this option to expensive for large ocean-going vessels; though the Port of Los Angeles and Port of Long Beach are actively seeking this as a solution (2004).#p#分页标题#e#
Installation or upgrade of a port area substation is most appropriate for terminals requiring high power loads, such as cruise terminals or very large cargo areas (2004). In order to provide emission benefits, the emissions associated with the electrical generation supplied by the substation must be significantly less than the emissions generated by auxiliary engines on the receiving vessels to ensure meaningful emission reductions. The second power generation option is the installation of one or two fuel cell units (200–250 kW size) at berths where smaller ships (e.g., tugboats, commercial fishing boats, and crew/supply boats) are hoteling and where natural gas is available as a fuel source. Fuel cell technology offers many advantages over existing diesel generators, including very low exhaust emissions, quieter operation, and improved thermal efficiency (2004). The US Navy, as well as many foreign navies, is considering the use of integrated electric plants that employ fuel cells in future ship designs (Friesen and Sylte, 2002). However, ships employing fuel cells for propulsion and fuel cells for auxiliary power or dockside power generation are still in development stages (2004). The third option for power generation is a demonstration project to install fuel cells on a barge that could maneuver within a port to supply power at multiple locations. This type of project may work well for cargo ships in berth where diesel generators producing auxiliary loads are in the 1–2 MWrange, as opposed to the cruise ships where the load is an order of magnitude higher (2004).
1. INTRODUCTION
In 1992, there were roughly about 1.291 million containers in the Port of Oakland and by 2006 it had increased by about 185% to about 2.391 million containers. With such sizable increases the effects have been seen in the local and national economics but one area that has been overlooked is the increased amounts of pollution. Here is a proposal on how to reduce pollution in the Port of Oakland while minimizing the effect in the increased number of ships coming into the Port of Oakland. Provided below is a graph of the number of containers for each year from 1992 to 2006.
Some history on the Port of Oakland, the Port began to admit container ships back in 1962. Container traffic has greatly increased the amount of cargo loaded and unloaded in the Port of Oakland. By the late 1960s, the Port of Oakland was the second largest port in the world in container tonnage. However, depth and navigation restrictions in San Francisco Bay limited its capacity. By the late 1970s it had been supplanted by the Ports of Los Angeles and Long Beach as the major container port on the West Coast.
In the Port of Oakland presently there are many ships equipped with large engines running on bunker fuel without emission controls, thousands of diesel trucks per day, diesel locomotives, and other polluting equipment. These activities at the Port of Oakland cause an array of environmental impacts that have seriously affect the local communities, marine, and land-based ecosystems throughout the region. Some of the impacts seen from the Port are an increased risk of cancer in nearby communities, increased regional smog, contamination of water, the introduction of destructive foreign species, aesthetic effects on local communities, and public lands (Bailey & Solomon, 2004).
The focus of this proposal is on the range of options available to move towards a greener seaport in Oakland. One thing to realize with any polluting industry, there are many ways to mitigate and eliminate health impacts though they heavily rely on the consideration of the public health, feasibility, and cost. For the Port of Oakland, the measures range from possible changes to idling limits for trucks, sweeping global changes in the international trade. The major reason for this proposal is because the Port of Oakland like many other ports throughout the world is complex pollution sources. Also like many other on-site processes there is not one single solution to solve all the problems. The best approach to take is to define the alternatives that can make significant improvements in the air quality, and to set goals for the best environmental practices that are stringent, but yet still achievable.
2. SOURCES OF AIR POLLUTION AT PORTS
Sea ports are a major source of air pollutants that affects the heath of people living in nearby communities, not to mention the problems that this can cause to regional air pollution. Major air pollutants include the following: diesel exhaust, particulate matter (PM), volatile organic compounds (VOCs), nitrogen oxides (NOx), ozone, and sulfur oxides (SOx). Air pollutants that come from the operation of the port include: carbon monoxide (CO), formaldehyde, heavy metals, dioxins, and pesticides used to fumigate produce.#p#分页标题#e#
Worldwide, marine vessels pour out about 14% of the NOx, and 5% of the SOx from all fossil fuel sources (2004). In 2000, commercial marine vessels accounted for roughly 7% of NOx and 6% of PM emissions from all mobile sources in the United States (2004). With an increasing number of imports these numbers are expected to rise. In 2004 the projections for 2007, large commercial ships were expected to emit 6-65 times more NOx per unit of engine power than diesel transit buses (2004). The US Environmental Protection Agency (EPA), is expecting the contributions of PM and NOx from marine vessels is double by the year 2020 (2004).
Presently the vast majority of on-land equipment currently in use at ports runs on diesel fuel. Cargo-handling equipment is classified as equipment that would be used to load and unload large cargo containers from ships, locomotives, and trucks. As well as shuttling those containers around for storage. Cargo-handling equipment includes gantry cranes, yard trucks, top-picks, side-picks, and forklifts. The gantry cranes are primarily used to load and unload ships, yard trucks are used in shuttling containers, and the others such as top-picks, side-picks, and forklifts perform jobs that are not listed above but required in running a port. Regulation of off-road equipment lags behind on-road trucks and buses by several decades. Emission standards for heavy diesel equipment emits about 15 times more PM and NOx that new highway trucks and buses.
3. EFFECTS ON HEALTH WITH AIR POLLUTION
Diesel exhaust is a mixture of particles, vapors, and gases emitted from the burning of diesel fuel. In addition to containing pollutants outlined above with their associated health impacts, diesel exhaust contains an estimated 450 different compounds, which about 40 of them are considered to be toxic air contaminants with negative effects on the health and the environment (2004). Studies of people exposed to diesel exhaust have reported some of the following eye and nose irritation, bronchitis, cough, phlegm, wheezing, and deterioration in lung function (2004). New scientific evidence suggests that diesel exhaust may have a casual role in the initiation of allergies and asthma.
Dozens of studies have shown that long-term exposure to diesel exhaust significantly increases the risk of lung cancer (2004). Some studies have also reported links between diesel exposure and other cancers, including bladder, kidney, stomach, multiple myeloma, leukemia, Hodgkin’s disease, non-Hodgkin’s lymphoma, and cancers of the oral cavity, pharynx, and larynx (2004).
Particulate matter (PM) pollution ranges from a coarse dust to very tiny sooty particles formed when gasoline or diesel is burned. It is the tiniest PM that can cause the greatest health concerns (2004). Dozens of studies link fine PM concentrations to increased hospital admissions for asthma attacks, chronic obstructive lung disease, bronchitis, pneumonia, heart disease, and premature deaths (2004).#p#分页标题#e#
Volatile organic compounds (VOCs) include a long list of chemicals used in industry, as well as chemicals emitted from motor vehicles such as diesel trucks and buses. VOCs are characterized by their ability to evaporate into the air and produce ozone smog and by their inherent toxicity (2004). Formaldehyde is very irritating to the airways, and is a probable carcinogen (2004). Toluene at occupational exposure levels has been associated with birth defects and miscarriages (2004). Other VOCs emitted by vehicles have also been linked to cancer, reproductive harm, asthma, or neurological disorders (2004).
Nitrogen oxides (NOx) have had numerous studies finding that it can cause toxic effects in the airways, leading to inflammation and to asthmatic reactions. In fact people with allergies or asthma have far stronger reactions to common allergens such as pollen when they have been exposed to NOx (2004).
Ozone, also known as ozone smog, is reactive gas produced when VOCs or NOx interact with the sunlight and split apart oxygen molecules in the air. Ozone can make people more susceptible to respiratory infections and can aggravate preexisting respiratory diseases, such as asthma (2004). Ozone can also cause irreversible changes to the lung structure, which eventually lead to chronic respiratory illness, such as emphysema and chronic bronchitis (2004).
Sulfur oxides (SOx) are produced from the burning of sulfur-containing fuels such as diesel and particularly high sulfur marine fuels, bunker fuel. These compounds include sulfur dioxide and a range of related chemical air pollutants. SOx reacts with water vapor in the air to create acidic aerosols that irritate the airways sometimes causing discomfort and coughing in healthy people, and often causing severe respiratory symptoms for asthmatics (2004).
Then lastly children are some of the most susceptible to air pollution because of their lungs are still in the developing and because their airways are narrower than those of adults. In addition, children often play outdoors during the day and thus may be more exposed. Children raised in heavily polluted areas have reduced lung capacity, prematurely aged lungs and increased risk of bronchitis and asthma compared to peers living in less polluted areas (2004).
4. SUGGESTED CONTROL MEAUSRES ON POLUTION AT THE PORT OF OAKLAND
Easily Achievable Approaches
Many ports around the world have adopted approaches that can significantly reduce their contribution to pollution to the surrounding areas. We hope in this proposal to show some of these and how they could benefit the Port of Oakland. Some of the measures that other places have done already that are easily achievable are to use cleaner fuels and enforcement of idling limits.
Cargo handling equipment and ships at the Port of Oakland currently run on a much dirtier fuel grade of diesel fuel that on-road diesel trucks. To put this in prospective, an ocean-going ship typically run on bunker oil, this is over 100 times the amount of sulfur than that of on-road diesel transportation (2004). Several cleaner fuel options are currently available and also compatible with the existing diesel engines. These include low sulfur diesel, diesel emulsions, biodiesel, Fischer-Tropsch diesel (2004). Note that low sulfur diesel is the most widely available and cheapest source to turn to but it does not provide nearly the same amount of reductions for certain pollutants (2004). See Table 2.#p#分页标题#e#
The intended use of low sulfur diesel is generally been intended to be used in the combination with emission controls, but it does not offer a substantial emission reduction even when used alone as a replacement fuel. Though as of 2003, the Port of Oakland has convinced most of its terminal operators to adopt low sulfur diesel for cargo handling equipment (2004).
Then in diesel emulsions, aqueous diesel, this can be used as an emissions reducer at ports also. There are presently three brands of aqueous diesel that have been verified by the California Air Resources Board (ARB) (2004). Although these only provide a slight decrease in NOx, some studies have shown that have shown significant decreases in PM with the use of this fuel (2004). Though note that on off-road equipment the results have not shown as impressive of results through studies (2004).
Another option is biodiesel, which is most commonly sold as a blend with 80% or more conventional diesel (2004). The emission benefits of these blends show a 10–20% improvement over regular diesel (2004). Pure biodiesel does offer more substantial PM and CO2 reductions—on the order of 50%—but at the expense of an increase in NOx, by as much as 10% (2004). However there are many engine manufacturers do not warrant their products for use with pure biodiesel, because it can cause corrosion in some engines. Biodiesel is distributed in many regions throughout the United States, though prices vary widely, as does the feedstock used to make biodiesel fuel, which can include used oils and grease, or farmed products such as corn. The biodegrade-ability of biodiesel makes it well suited for marine uses because spills are not a serious problem.
Lastly, Fischer–Tropsch diesel is usually made from coal, but is sometimes made from natural gas, leading to the recent acronym Gas to liquids (GTL) fuel (2004). Much of the Fischer–Tropsch diesel in the United States is imported from Malaysia. However, plans may be underway to build a full-scale
US plant soon (2004). Fischer–Tropsch fuel can reduce emissions of NOx by more than 10% and of several other pollutants in the range of 30% (2004). The costs and overall environmental benefits are contingent on transport and feedstock’s, and are not yet well known at the time of writing.
Another area that is under the category of easily achievable approaches is the use of idling limits. With having well-enforced idling restrictions the savings are amazing because one can save on hundreds of gallons of fuel per vehicle and not to mention that a cost effective way to substantially reduce diesel emissions from trucks and locomotives. The reason we can have idling limits in place for the trucks and locomotives is due to the fact that they normally tend to stand idle in the port for long periods of time.
The cost of idling restrictions would roughly be about US$800,000 per year to cover signage and additional personnel to monitor compliance, this yields in a cost ratio of roughly US$2000 per ton of NOx reduced, which is extremely cost competitive compared to other measures being considered (2004). Additionally, the cost estimates do not include other pollutants that are significantly reduced, such as PM and carbon dioxide. Finally, this measure saves millions of dollars in fuel costs as well as engine maintenance costs (2004). Note that in 2003 the state of California did implement an idling law for all trucks in ports in major metropolitan areas, like Oakland, to thirty minutes (2004). Though this is helpful there is perhaps more California can do on this measure.#p#分页标题#e#
Through this measure locomotives can also substantially reduce pollution through automatic idling control devices. Switching engines are currently used to move trains around within rail yards, are generally highly polluters and tend to idle about 75% of the time (2004). This makes them perfect candidates for automatic idling controls. These controls reduce fuel use, diesel emissions, and noise. The EPA estimates that 10% of all rail fuel could be saved, which translates to 366 million gallons and US$240 million (2004). Most automatic idling controls for locomotives cost roughly US$6000–US$10,000, with more elaborate devices costing up to US$40,000 (2004).
5. POLLUTION MEASURES THAT REQUIRE CAPITAL INVESTMENTS
One thing about pollution mitigation measures there are parts that do require infrastructure and also capital investments that are not covered. These changes can be used to further reduce their impacts on pollution. Some of the measures that would require investments include retrofit, repower, and retirement of vehicles, equipment, locomotives, and ships. Not to mention that there is the possibility of having equipment running on alternative fuels such as natural gas.
One area that has been lagging behind the modern emission standards are some of the oldest, most pollutant vehicles, equipment, and vessels that need to be replaced. In many cases, the exhaust systems can be retrofitted with emission controls, which can significantly reduce exhaust emissions. While replacement of older vehicles and equipment is often the most preferable solution, retrofits and repowers often tend to offer a more practical solution for existing fleet. Repowers are sometimes limited by the age and configuration of the vehicle or piece of equipment; however in most cases at least one control technology can be retrofitted to any vehicle or piece of equipment (2004).
Recently the Port of Oakland has begun a program to clean up yard equipment, funded through a settlement that the Port reached with the surrounding community over an expansion (2004). Terminal operators can use the funds of this voluntary program to retrofit, repower or make cleaner purchases of terminal equipment. The Port of Oakland plans also to start a similar program for offsite trucks visiting the port terminals, with the remaining settlement money (2004).
Another area that has high polluting is the switching locomotives that can actually be repowered with several low-emitting engine options. These options include natural gas and hybrid battery-electric. Several alternative fuel and hybrid-electric locomotives are in the market and are available for purchase. Some places have performed converting diesel locomotives to natural gas fuel. This option requires an overhauling of the engine and fueling system. The cost of this conversion is roughly US$400,000 to US$800,000 per locomotive (2004). In repowering these locomotives with the use of natural gas engines it shows roughly a reduction in NOx by 4.8 tons a year (2004). This solution can not be overlooked for the Port of Oakland because of the fact that natural gas infrastructure is in existence.#p#分页标题#e#
The other option for locomotives is a hybrid-electric switching locomotive which retails for US$750,000, which is roughly half the cost of a conventional locomotive. Not to mention that under this technology that the locomotive reduces both PM and NOx by 85% or 13.5 tons per year (2004).
The replacement of the locomotives would primarily concern themselves with the locomotives that were built before 1973 or the engines that have yet to meet federal standards providing the most significant emission benefits (2004). The switching locomotives are good candidates for repowers due to they are idle for such a long periods of time.
With the locomotives being a major part of the rail yards, the item that still needs to be discussed that is in the harbor is the tugboats. A staggering statistic states that the average tugboat in the San Francisco Bay Area found that the average age of the tugboat in service is 30 years or more (2004). These tugboats themselves contribute a big amount to the pollution because most of them have a two-cycle engine. Though one great thing about tugboats is they are great candidates for being repowered. The average cost of replacement can roughly cost around US$400,000 and yields in reduction in NOx by 73 tons per year (2004).
Alternative fuels for yard equipment is one last major area under consideration for pollution measures that require public investment. When looking to the equipment such as terminal tractors and other cargo handling equipment the type of fuel it uses propane and natural gas (NG) should be considered. The benefits of choosing these fuels as compared to diesel are very substantial when looking into reducing emissions. Switching to alternative fuels can completely eliminate emissions of diesel particulate matter (PM) and significantly reduces NOx emissions (2004). For example NG powered buses have demonstrated PM emissions are 20-100 times lower than its diesel counterpart (2004). Though natural gas engines do have significant lower NOx and PM they do possibly have higher CO and CO2 emissions and slightly higher hydrocarbon emissions (2004). Note that these increases can be considered minimal when seeing the amount of reduction in NOx and PM emissions that have been seen in natural gas.
6. FUTURE TECHNOLOGIES
One future technology is having emission controls on ships. Presently in Europe there is a lot of work being done to explore the emission control for ships. Selective Catalytic Reduction (SCR), a control technology that drastically reduces the smog-forming NOx coming from the smokestacks has been installed on over 100 large ships, mostly in the Baltic Sea area (2004). Though this technology still has several things to overcome, including cost, it could potentially shown as the most effective way to measure for mainstream use (2004).
Another area is looking into shore-side power for ships while they are at dock. Ships normally when they are docked they use diesel fueled auxiliary engines while docked to run systems such as lights, pumps, and fans. The engine can be set idling for many days at a time which can cause large amount of pollution not to mention the amount of noise this generates. Recently in 2001 the Port of Oakland has begun to install power plug-ins for tugboats (2004). This allowed the tugboats to shut down their engines while at dock. Though Oakland does considers this option to expensive for large ocean-going vessels; though the Port of Los Angeles and Port of Long Beach are actively seeking this as a solution (2004).#p#分页标题#e#
Installation or upgrade of a port area substation is most appropriate for terminals requiring high power loads, such as cruise terminals or very large cargo areas (2004). In order to provide emission benefits, the emissions associated with the electrical generation supplied by the substation must be significantly less than the emissions generated by auxiliary engines on the receiving vessels to ensure meaningful emission reductions. The second power generation option is the installation of one or two fuel cell units (200–250 kW size) at berths where smaller ships (e.g., tugboats, commercial fishing boats, and crew/supply boats) are hoteling and where natural gas is available as a fuel source. Fuel cell technology offers many advantages over existing diesel generators, including very low exhaust emissions, quieter operation, and improved thermal efficiency (2004). The US Navy, as well as many foreign navies, is considering the use of integrated electric plants that employ fuel cells in future ship designs (Friesen and Sylte, 2002). However, ships employing fuel cells for propulsion and fuel cells for auxiliary power or dockside power generation are still in development stages (2004). The third option for power generation is a demonstration project to install fuel cells on a barge that could maneuver within a port to supply power at multiple locations. This type of project may work well for cargo ships in berth where diesel generators producing auxiliary loads are in the 1–2 MWrange, as opposed to the cruise ships where the load is an order of magnitude higher (2004).
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