Total fuel-cycle analysis of heavy-duty vehicles using biofuels and natural gas-based alternative fuels

Heavy-duty vehicles (HDVs) present a growing energy and environmental concern worldwide. These vehicles rely almost entirely on diesel fuel for propulsion and create problems associated with local pollution, climate change, and energy security. Given these problems and the expected global expansion of HDVs in transportation sectors, industry and governments are pursuing biofuels and natural gas as potential alternative fuels for HDVs. Using recent lifecycle datasets, this paper evaluates the energy and emissions impacts of these fuels in the HDV sector by conducting a total fuel-cycle (TFC) analysis for Class 8 HDVs for six fuel pathways: (1) petroleum to ultra low sulfur diesel; (2) petroleum and soyoil to biodiesel (methyl soy ester); (3) petroleum, ethanol, and oxygenate to e-diesel; (4) petroleum and natural gas to Fischer-Tropsch diesel; (5) natural gas to compressed natural gas; and (6) natural gas to liquefied natural gas. TFC emissions are evaluated for three greenhouse gases (GHGs) (carbon dioxide, nitrous oxide, and methane) and five other pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, particulate matter, and sulfur oxides), along with estimates of total energy and petroleum consumption associated with each of the six fuel pathways. Results show definite advantages with biodiesel and compressed natural gas for most pollutants, negligible benefits for e-diesel, and increased GHG emissions for liquefied natural gas and Fischer-Tropsch diesel (from natural gas).     

Controlling air pollution from passenger ferries: cost-effectiveness of seven technological options

Continued interest in improving air quality in the United States along with renewed interest in the expansion of urban passenger ferry service has created concern about air pollution from ferry vessels. This paper presents a methodology for estimating the air pollution emissions from passenger ferries and the costs of emissions control strategies. The methodology is used to estimate the emissions and costs of retrofitting or re-powering ferries with seven technological options (combinations of propulsion and emission control systems) onto three vessels currently in service in San Francisco Bay. The technologies include improved engine design, cleaner fuels (including natural gas), and exhaust gas cleanup devices. The three vessels span a range of ages and technologies, from a 25-year-old monohull to a modern, high-speed catamaran built only four years ago. By looking at a range of technologies, vessel designs, and service conditions, a sense of the broader implications of controlling emissions from passenger ferries across a range of vessels and service profiles is provided. Tier 2-certified engines are the most cost-effective choice, but all options are cost-effective relative to other emission control strategies already in place in the transportation system.     

Emissions tradeoffs among alternative marine fuels: total fuel cycle analysis of residual oil, marine gas oil, and marine diesel oil

Worldwide concerns about sulfur oxide (SOx) emissions from ships are motivating the replacement of marine residual oil (RO) with cleaner, lower-sulfur fuels, such as marine gas oil (MGO) and marine diesel oil (MDO). Vessel operators can use MGO and MDO directly or blended with RO to achieve environmental and economic objectives. Although expected to be much cleaner in terms of criteria pollutants, these fuels require additional energy in the upstream stages of the fuel cycle (i.e., fuel processing and refining), and thus raise questions about the net impacts on greenhouse gas emissions (primarily carbon dioxide [CO2]) because of production and use. This paper applies the Total Energy and Environmental Analysis for Marine Systems (TEAMS) model to conduct a total fuel cycle analysis of RO, MGO, MDO, and associated blends for a typical container ship. MGO and MDO blends achieve significant (70-85%) SOx emissions reductions compared with RO across a range of fuel quality and refining efficiency assumptions. We estimate CO2 increases of less than 1% using best estimates of fuel quality and refinery efficiency parameters and demonstrate how these results vary based on parameter assumptions. Our analysis suggests that product refining efficiency influences the CO2 tradeoff more than differences in the physical and energy parameters of the alternative fuels, suggesting that modest increases in CO2 could be offset by efficiency improvements at some refineries. Our results help resolve conflicting estimates of greenhouse gas tradeoffs associated with fuel switching and other emissions control policies.     

Effect of copper on growth of an aquatic macrophyte,Elodea canadensis

Elodea canadensis has been proposed as a potential biomonitor due to its wide distribution and apparent ability to accumulate pollutants in aquatic ecosystems. We investigated the effects of copper sulfate on growth in E. canadensis to determine its effectiveness as a biomonitor of copper pollution in aquatic systems and whether growth is a suitable index of sub-lethal stress. Copper sulfate significantly slowed or stopped growth at all concentrations (low: 1 ppm, medium: 5 ppm, high: 10 ppm of copper sulfate) used. Final plant drymass was significantly lower in medium and high copper treatments compared with controls. E. canadensis appears to be very sensitive to copper levels, and may be useful as a biomonitor of copper levels in aquatic systems. However, its utility as a bioaccumulator may be limited, because we observed senescence of most leaves in all copper-treated plants following 4 weeks of treatment.     

Effects of lead contamination on the growth of lythrum salicaria (purple loosestrife)

The ability of individual species to tolerate or accumulate heavy metal pollutants has been investigated widely. Although invasive species may become established more easily in disturbed environments, relatively little is known about how an ability to tolerate pollutants might give invasive species a competitive advantage. This study is part of a series of experiments investigating native and invasive species interactions with chemical pollution and other forms of disturbance. The purpose of this experiment was to investigate the effects of lead on the growth of Lythrum salicaria. We exposed plants to different concentrations of lead and measured different growth parameters, such as biomass, length, leaf number, and biomass allocation to roots. For most measures, plants grown in lead-free conditions were larger than plants exposed to lead. Plants in the low (500 mg/l) and medium (1,000 mg/l) lead treatments did not differ from each other, while plants in the high (2,000 mg/l) lead treatment were significantly smaller. However, the biomass allocation to roots was not significantly different among treatments. Although their growth is affected, individuals of Lythrum salicaria demonstrated tolerance to lead contamination, which may aid in their colonization in lead-polluted wetlands.     

Engagement with climate change and the environment: a review of the role of relationships to place

A growing body of literature examines how human bonds with place influence engagement with climate change and other environmental issues. Yet, studies in this vein derive from a number of disconnected literatures with a variety of place concepts employed. We set out to assess the current state of knowledge in this field and provide a framework for analysing dimensions of relations to place and their links with environmental engagement. We systematically analysed the characteristics of 66 studies identified for: focus of research, location, methods, and findings, particularly whether relationships to place aided in environmental engagement. We also categorised the studies according to our dimensions of place relations framework, cultural and environmental contexts, and intensity of climate impacts experienced. The answer to our guiding research question – whether place attachment was an effective way to communicate with people about climate change and get them actively engaged with it – was yes (74.2%), but with considerable variation according to these characteristics and dimensions. Based on this analysis, we identify gaps in current research and suggest critical paths for future research, especially in terms of geography and demography because of their implications for justice and equity in the processes of climate change mitigation and adaptation. Needed future research includes studies of place relations in regards to climate change specifically, studies in the Global South, of minority populations, beyond rural areas, and qualitative or mixed-method studies able to draw out the complexities of relations to place.     

A CALIBRATION PROCEDURE USING TOPMODEL TO DETERMINE SUITABILITY FOR EVALUATING POTENTIAL CLIMATE CHANGE EFFECTS ON WATER YIELD1

ABSTRACT: An evaluation was conducted on three forested upland watersheds in the northeastern U.S. to test the suitability of TOPMODEL for predicting water yield over a wide range of climatic scenarios. The analysis provides insight of the usefulness of TOPMODEL as a predictive tool for future assessments of potential long-term changes in water yield as a result of changes in global climate. The evaluation was conducted by developing a calibration procedure to simulate a range of climatic extremes using historical temperature, precipitation, and streamfiow records for years having wet, average, and dry precipitation amounts from the Leading Ridge (Pennsylvania), Fernow (West Virginia), and Hubbard Brook (New Hampshire) Experimental Watersheds. This strategy was chosen to determine whether the model could be successfully calibrated over a broad range of soil moisture conditions with the assumption that this would be representative of the sensitivity necessary to predict changes in streamfiow under a variety of climate change scenarios. The model calibration was limited to a daily time step, yet performed reasonably well for each watershed. Model efficiency, a least squares measure of how well a model performs, averaged between 0.64 and 0.78. A simple test of the model whereby daily temperatures were increased by 1.7°C, resulted in annual water yield decreases of 4 to 15 percent on the three watersheds. Although these results makes the assumption that the model components adequately describe the system, this version of TOPMODEL is capable to predict water yield impacts given subtle changes in the temperature regime. This suggests that adequate representations of the effects of climate change on water yield for regional assessment purposes can be expected using the TOPMODEL concept.     

Energy use and emissions from marine vessels: a total fuel life cycle approach

Regional and global air pollution from marine transportation is a growing concern. In discerning the sources of such pollution, researchers have become interested in tracking where along the total fuel life cycle these emissions occur. In addition, new efforts to introduce alternative fuels in marine vessels have raised questions about the energy use and environmental impacts of such fuels. To address these issues, this paper presents the Total Energy and Emissions Analysis for Marine Systems (TEAMS) model. TEAMS can be used to analyze total fuel life cycle emissions and energy use from marine vessels. TEAMS captures "well-to-hull" emissions, that is, emissions along the entire fuel pathway, including extraction, processing, distribution, and use in vessels. TEAMS conducts analyses for six fuel pathways: (1) petroleum to residual oil, (2) petroleum to conventional diesel, (3) petroleum to low-sulfur diesel, (4) natural gas to compressed natural gas, (5) natural gas to Fischer-Tropsch diesel, and (6) soybeans to biodiesel. TEAMS calculates total fuel-cycle emissions of three greenhouse gases (carbon dioxide, nitrous oxide, and methane) and five criteria pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, particulate matter with aerodynamic diameters of 10 microm or less, and sulfur oxides). TEAMS also calculates total energy consumption, fossil fuel consumption, and petroleum consumption associated with each of its six fuel cycles. TEAMS can be used to study emissions from a variety of user-defined vessels. This paper presents TEAMS and provides example modeling results for three case studies using alternative fuels: a passenger ferry, a tanker vessel, and a container ship.     

Optimal fleetwide emissions reductions for passenger ferries: an application of a mixed-integer nonlinear programming model for the New York-New Jersey Harbor

Emissions from passenger ferries operating in urban harbors may contribute significantly to emissions inventories and commuter exposure to air pollution. In particular, ferries are problematic because of high emissions of oxides of nitrogen (NOx) and particulate matter (PM) from primarily unregulated diesel engines. This paper explores technical solutions to reduce pollution from passenger ferries operating in the New York-New Jersey Harbor. The paper discusses and demonstrates a mixed-integer, non-linear programming model used to identify optimal control strategies for meeting NOx and PM reduction targets for 45 privately owned commuter ferries in the harbor. Results from the model can be used by policy-makers to craft programs aimed at achieving least-cost reduction targets.