Transportation Greenhouse Gas Emissions Research Articles

Patient transport greenhouse gas emissions from outpatient care at an integrated health care system in the Northwestern United States, 2015–2020

Climate change threatens human health, and health care as an industry is responsible for a significant fraction of greenhouse gas (GHG) emissions. We examine the reduction in GHG emissions from transportation to outpatient clinic visits with the growth in telehealth services. This is a retrospective review of outpatient care at a health system serving over 600,000 members. Using average distances, we calculate transportation-related GHG emissions for ambulatory visits. The ambulatory visit carbon intensity is the total GHG emissions normalized by number of patient visits annually. From 2015 to 2020, total outpatient visits increased at 3.2% annually, to 2.7 million. Telehealth visits increased by an average of 53.2% annually while in-person visits saw modest gains of 1.5% annually until 2020, when they declined 46.2%. Transportation GHG emissions rose from 18.5 to 19.6 (in 2019) before declining to 10.5 kt CO2-eq in 2020. Ambulatory visit carbon intensity monotonically declined from 8 to 4 kg CO2-eq per visit. Increasing telehealth use in an integrated health system in the Pacific northwest of the United States corresponded to a dramatic decrease in ambulatory visit carbon intensity.

Multi-objective optimization of petroleum product logistics in Eastern Indonesia region

The transportation sector is one of the largest fuel consumers and pollutant contributors worldwide. The International Maritime Organization predicts that the greenhouse gas (GHG) emissions from transportation will be increasing significantly until 2050, driven by the growth in global maritime trade. Managing logistics distribution routes is considered a possible approach for controlling GHG emissions. This study aims to implement a green logistics concept in the logistics distribution of petroleum products—gasoline, kerosene, and diesel—in eastern Indonesia, whose supply sources are refineries located in Balikpapan and Kasim. A multi-objective approach is used to implement the green logistics concept. Multi-objective optimization is conducted using the AIMMS software to optimize a logistics system consisting of a multi-depot, multi-product, and heterogeneous fleet. The optimization is performed to determine the best logistics route and the amount of products delivered using certain types of fleets to minimize transportation cost and GHG emissions using constant speed. In addition, this study also investigates the effect of variable speed on cost and CO2 emissions. For the constant speed case, the distribution routes obtained for the minimizing cost scenario tends to maximize the utilization of transit terminals while in the minimizing emissions scenario tends to deliver directly to the distribution centers, so the route decision in multi-objective optimization scenario is combination of the two. The multi-objective optimization results an 11% cost reduction and a 17% GHG emission reduction compared with the current values. The comparison between constant and variable speed reveals that the variable speed is preferred to constant speed as it gives lower emissions with slight changes in cost.

Blending blue hydrogen with natural gas for direct consumption: Examining the effect of hydrogen concentration on transportation and well-to-combustion greenhouse gas emissions

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H2 fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H2 and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H2 is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emissions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50–100 million m3/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO2-free scenario. While hythane contains 15% H2 by volume only 5% of the gas’ energy comes from H2, limiting its GHG benefit.

Mobility Styles and Car Ownership—Potentials for a Sustainable Urban Transport

Decision-makers in cities worldwide have the responsibility to contribute to the reduction of greenhouse gas emissions in urban transport. Therefore, effective measures and policies that allow for a change in people’s mobility towards sustainable mobility must be derived. To understand how different people respond to measures and policies, and to increase the effectiveness of such policies, individual mobility needs and mobility determinants have to be considered. For this, the definition of individual mobility styles as holistic descriptions considering travel behavior, attitudes, as well as life stages is useful. This study presents a segmentation approach that identifies eight urban mobility styles by using data from a multidimensional survey conducted in Berlin and San Francisco. We applied a cluster analysis with both behavioral and attitudinal characteristics as segmentation criteria. By analyzing the characteristics, we identified a mobility style—the Environmentally Oriented Multimodals—that is environmentally oriented, but not yet all people in this cluster are sustainable in their mobility. Thus, they are the group with the highest potential to accept and use sustainable mobility. Additionally, we found that within the Environmentally Oriented Multimodals, the change from one life stage to another is also likely to be accompanied by a car acquisition.

On life-cycle sustainability optimization of enhanced weathering systems

Abstract Enhanced weathering is a simple and scalable negative emissions technology with an estimated carbon dioxide removal potential of multiple gigatons per year. To date, the only life-cycle assessment of enhanced weathering was published by Lefebvre et al. (2019) in this journal. They estimated the carbon dioxide removal potential in Sao Paolo State in Brazil to be 1.3–2.4 Mt/y, examined the penalty from transportation greenhouse gas emissions, and pointed out that using life-cycle assessment can give more reliable estimates of climate change mitigation potential of enhanced weathering systems. In this letter, we discuss the limitations of life-cycle assessment of enhanced weathering, and then propose a more comprehensive life-cycle optimization approach, where the system configuration can be automatically synthesized to maximize environmental performance. This concept can be extended further to life-cycle sustainability optimization by including economic and social dimensions.

From traffic data to GHG emissions: A novel bottom-up methodology and its application to Valencia city

Sustainable cities will only be possible with effective local measures tackling Greenhouse Gas (GHG) emissions. Transport and mobility represent the main sources of these emissions, particularly in urban settings. National and local public administrations need accurate and more responsive tools to quantify GHG emissions. Digitisation and ICTs are key elements in the development of such tools, which, additionally, have to be based on robust methodologies validated by the scientific community. This research presents a bottom-up methodology for the quantification of road traffic's GHG emissions with higher levels of immediacy and spatial resolution when compared to other already existing methods. The methodology uses data from the urban traffic control and monitoring systems as a baseline to calculate emissions. A pilot test has been conducted in Valencia city (Spain). Its results show a highly detailed picture of GHG emission in the city with high temporal (hour) and space (street) resolutions. The emission patterns reflect the dynamics of the city and its citizenship mobility. Since the tools developed for the pilot test can be adapted to other cities, public decision-makers could benefit from a precise diagnosis system based on traffic data to offer and evaluate solutions to reduce road transport GHG emissions.

Alternative Fuels and Technologies for Short Sea Shipping

Awareness of the consequences of excessive greenhouse gas emissions in maritime transport has prompted research on the use of alternative fuels and technology, towards environmentally neutral ship propulsion, which has resulted in a number of possibilities. This review provides a systematic overview of the current state of use of ship propulsion and alternative options from the aspect of costs, infrastructure, regulations, availability, environmental protection, technology and the perspective of complete decarbonisation by 2050.

Combining expansion in pulp capacity with production of sustainable biofuels – Techno-economic and greenhouse gas emissions assessment of drop-in fuels from black liquor part-streams

Drop-in biofuels from forest by-products such as black liquor can help deliver deep reductions in transport greenhouse gas emissions by replacing fossil fuels in our vehicle fleet. Black liquor is produced at pulp mills that can increase their pulping capacity by upgrading some of it to drop-in biofuels but this is not well-studied. We evaluate the techno-economic and greenhouse gas performance of five drop-in biofuel pathways based on BL lignin separation with hydrotreatment or black liquor gasification with catalytic synthesis. We also assess how integrated biofuel production impacts different types of pulp mills and a petroleum refinery by using energy and material balances assembled from experimental data supplemented by expert input. Our results indicate that drop-in biofuels from black liquor part-streams can be produced for ~80 EUR2017/MWh, which puts black liquor on the same footing (or better) as comparable forest residue-based alternatives. The best pathways in both production routes have comparable costs and their principal biofuel products (petrol for black liquor gasification and diesel for lignin hydrotreatment) complement each other. All pathways surpass European Union’s sustainability criteria for greenhouse gas savings from new plants. Supplementing black liquor with pyrolysis oil or electrolysis hydrogen can improve biofuel production potentials and feedstock diversity, but better economic performance does not accompany these benefits. Fossil hydrogen represents the cheaper option for lignin hydrotreatment by some margin, but greenhouse gas savings from renewable hydrogen are nearly twice as great. Research on lignin upgrading in industrial conditions is recommended for reducing the presently significant performance uncertainties.

Consequences of Transport Low-Carbon Transitions and the Carbon, Land and Water Footprints of Different Fuel Options in The Netherlands

Transport greenhouse gas emissions are mainly caused by the use of fossil fuels, e.g., gasoline and diesel. This case study for The Netherlands calculates how alternative fuels, e.g., electricity, hydrogen or biofuels, contribute to policy aims to decarbonize transport. Alternative fuels, produced in various ways, have different carbon (CF), land (LFs) and water footprints (WFs). This study assesses CFs, LFs and WFs for fuels (kgCO2e/m2/m3 per GJ), showing differences among fuels dependent on primary energy sources. It calculates CFs, LFs and WFs for four scenarios with different fuels. The biofuel scenario is not attractive. CFs slightly decrease, while LFs and WFs increase enormously. The electricity scenario has small CFs and the smallest LFs and WFs, but this is only when using wind or solar energy. If storage is needed and hydrogen is produced using wind energy, CFs double from 3055 to 7074 kg CO2e, LFs increase from 15 × 106 to 43 × 106 m2 and WFs from 3 × 106 to 37 × 106 m3 compared to the electricity scenario. The case study shows that wise fuel choices contribute to policy aims to decarbonize transport, although LFs and WFs are also important to consider. These case study results are relevant for sustainable transportation transitions worldwide.

The net greenhouse gas impact of the Jubilee line extension in London, UK

As cities work to reduce their total greenhouse gas (GHG) emissions, the transportation sector is lagging, accounting for a growing percentage of total emissions in many cities. The provision of public transit, and specifically urban rail transit, is widely seen as a useful tool for reducing urban transportation GHG emissions. More research, however, is needed to understand the net impact of new metro rail infrastructure on urban emissions and guide efforts to maximise the GHG savings through rail investments. This paper examines the net GHG emissions of the Jubilee line extension (JLE) in London, UK. The GHG emissions associated with construction, operation, ridership and changes in urban density associated with the provision of the new metro rail infrastructure are assessed. These components are then combined and compared to calculate the net GHG impact across the study period, which extends from opening in 1999 through 2011. The capital GHG emissions from construction of the JLE are calculated as 530 kilotonnes carbon dioxide equivalent (CO2e). The initial mode shift from other rail lines and long-term mode change from automobiles result in yearly GHG savings from riders on the JLE. A quasi-experimental analysis of land-use change near the JLE finds no calculable GHG saving from increased residential density. The GHG payback period is calculated between 13 and 19 years.

Rolling coal: The greenhouse gas emissions of coal rail transport for electricity generation

This study analyzes datasets from the Energy Information Administration, Environmental Protection Agency, and the U.S. Geological Survey to build a detailed picture of the CO2-eq emissions generated by coal rail transportation over the past decade. We use a GIS-based network analysis to illustrate how coal transportation routes and shipments have changed since 2008. Coal basins are characterized by type and emission intensities, and the scale of transportation emissions are compared to power plant operational emissions. The results show that rail transportation distances range from 0 km to over 3500 km. Transportation emissions can be as high as 35% of a power plant’s operational emissions – a number significantly higher than previous literature estimates. Additionally, implementation of post-combustion Carbon Capture and Storage (CCS) at existing plants may further increase transportation emissions. We conclude by recommending using at least regionalized distance factors rather than US-wide averages to more accurately account for transportation emissions within life cycle assessments and carbon footprints of coal power.

Developing a greenhouse gas life cycle assessment framework for natural gas transmission pipelines

As demand for natural gas increases, it is important to understand its life cycle emission intensity. A framework is developed for performing bottom-up greenhouse gas (GHG) life cycle assessment of natural gas transmission pipelines to assist project environmental assessments. Three large-scale pipelines in Canada were examined: Alliance mainline (50 million m3/d, 3000 km), Prince Rupert phase 1 (PR1, 57 million m3/d, 878 km), and Prince Rupert phase 2 (PR2, 102 million m3/d, 878 km). Fundamental engineering principles are used for calculation accuracy, with a sensitivity analysis to identify key parameters. The model boundary includes pipeline construction, operation, and decommissioning. The resulting transportation GHG emission intensities are 1.49, 0.77, and 1.78 gCO2eq/GJ.km for the Alliance, PR1, and PR2 projects, respectively. The operating phase represents 78%–95% of the overall emissions. Operating at higher pressures could reduce emission intensity by up to 49% by increasing flow efficiency. The research provides a user-friendly open-source template that can be used to examine alternative scenarios.

Transport oil product consumption and GHG emission reduction potential in China: An electric vehicle-based scenario analysis.

China’s transport sector is facing enormous challenges from soaring energy consumption and greenhouse gas (GHG) emissions. Transport electrification has been viewed as a major solution to transportation decarbonization, and electric vehicles (EVs) have attracted considerable attention from policymakers. This paper analyzes the effects of the introduction of EVs in China. A system dynamics model is developed and applied to assess the energy-saving and emission-reducing impacts of the projected penetration of EVs until the year 2030. Five types of scenarios of various EV penetration rates, electricity generation mixes, and the speed of technological improvement are discussed. Results confirm that reductions in transport GHG emissions and gasoline and diesel consumption by 3.0%–16.2%, 4.4%–16.1%, and 15.8%–34.3%, respectively, will be achieved by 2030 under China’s projected EV penetration scenarios. Results also confirm that if EV penetration is accompanied by decarbonized electricity generation, that is, the use of 55% coal by 2030, then total transport GHG emissions will be further reduced by 0.8%–4.4%. Moreover, further reductions of GHG emissions of up to 5.6% could be achieved through technological improvement. The promotion of EVs could substantially affect the reduction of transport GHG emissions in China, despite the uncertainty of the influence intensity, which is dependent on the penetration rate of EVs, the decarbonization of the power sector, and the technological improvement efficiency of EVs and internal combustion engine vehicles.

Coordinating soil and rock material in urban construction – Scenario analysis of material flows and greenhouse gas emissions

Abstract Construction is associated with quarrying as well as heavy transportation of soil and rock materials, in and out of construction sites. Both quarrying and transportation of the excavated materials result in negative environmental impact due to energy use and greenhouse gas (GHG) emissions. Moreover, soil and rock materials of suitable geotechnical quality for construction are a scarce natural resource in some urban regions. These issues have urged the need to optimize the use of quarry materials on-site and thereby reduce transportation. Still, internal flows of soil and rock materials in urban areas have not been well analyzed. This study presents a model to analyze future soil and rock flows in terms of material quality and quantities in urban areas. Furthermore, the study analyses the possibility of recycling excavated soil and rock and thereby reduce transportation and transport-related GHG emissions. The study applies the model in a case study to analyze integrating future residential and non-residential developments and a highway project. The case study revealed that excavated material would be generated in enough volumes to potentially cover the quarry materials demanded for providing stability and permeability to buildings, streets and highway. The scenario analysis showed that provision of strategically located recycling sites for material coordination could reduce the demand for soil and rock transportation as well as transport-related GHG emissions i.e. by 23–36% per area, compared to a business as usual scenario. The study shows that internal soil and rock flows within regions can be modelled by using data from development plans and geological maps. The model results may serve as a basis for decision making regarding strategic material management in urban planning.

Cap‐and‐Invest Systems Critical to Achieving Emission Reductions and Technology Gains in Transportation Sector

The transportation sector is the greatest source of greenhouse gas (GHG) emissions in the United States, accounting for more than 30 percent of GHG emissions nationwide and well over 40 percent in many states, eclipsing emissions from the electricity sector and industry. Of these transportation emissions, approximately 59 percent come from the more than 272 million light‐duty vehicles most of us drive every day. Capping transportation GHG emissions and investing in programs that accelerate the just transition to clean, efficient, and affordable transportation is critical to achieving a healthier environment. Such market‐based GHG emissions‐reduction programs have the potential to catalyze the widespread adoption of electric vehicles by funding incentives for vehicle purchases and charging infrastructure.

Low-Carbon Quick Wins: Integrating Short-Term Sustainable Transport Options in Climate Policy in Low-Income Countries

In low income countries (LICs) in Africa and Asia per capita transport greenhouse gas emissions are relatively low but are expected to grow. Therefore, a substantial reduction in projected increases is required to bring emissions in line with long-term global climate objectives. Literature on how LICs are integrating climate change mitigation and sustainable transport strategies is limited. Key drivers of transport policy include improving accessibility, congestion, air quality, energy security, with reducing greenhouse gas emissions being of lower priority. This paper assesses the current status, feasibility and potential of selected low-carbon transport measures with high sustainable development benefits that can be implemented in the short to medium term, so- called ‘quick wins’. It examines to what extent ten such quick wins are integrated in climate change strategies in nine low- and middle-income countries in Africa and South Asia. The research method comprises expert interviews, an online questionnaire survey of experts and policymakers in the focus countries, and a review of literature and government plans. Results indicate that sustainable urban transport policies and measures are considered high priority, with vehicle-related measures such as fuel quality and fuel economy standards and electric two- and three-wheelers being of key relevance. In existing national climate change strategies, these quick wins are integrated to a certain extent; however, with better coordination between transport and energy and environment agencies such strategies can be improved. A general conclusion of this paper is that for LICs, quick wins can connect a ‘top-down’ climate perspective with a ‘bottom-up’ transport sector perspective. A knowledge gap exists as to the mitigation potential and sustainable development benefits of these quick wins in the local context of LICs.

Using comparative socio-ecological modeling to support Climate Action Planning (CAP)

We present a comparative socio-ecological modeling approach to identify possible improvement opportunities for Climate Action Plans (CAPs), focusing on two cities, Chicago and Stockholm. The aim is to provide a tool for capturing and addressing deep-rooted behavioral and institutional preferences that may aggravate greenhouse gas (GHG) emissions in cities. Socio-economic activities, land use change, and future urban forms are considered and forecast to the year 2040 on 30m × 30m spatial grids. GHG emissions associated with these urban development aspects are calculated and compared between the cities. Innovative policy instruments for growth control and zoning (GCZ) are simulated and tested through the socio-ecological model, to determine their effectiveness when added to other interventions included in the CAPs. Our findings show that behavioral/institutional preference for sprawl, its low-density form, and resultant carbon sink losses are main factors driving current and future residential and transportation GHG emissions in Chicago. GCZ policies are shown to counteract and mitigate around 20% of these factors in the form of future GHG emissions.

Decomposition of Al2O3-Supported PdSO4 and Al2(SO4)3 in the Regeneration of Methane Combustion Catalyst: A Model Catalyst Study

Exhaust gas aftertreatment systems play a key role in controlling transportation greenhouse gas emissions. Modern aftertreatment systems, often based on Pd metal supported on aluminum oxide, provide high catalytic activity but are vulnerable to sulfur poisoning due to formation of inactive sulfate species. This paper focuses on regeneration of Pd-based catalyst via the decomposition of alumina-supported aluminum and palladium sulfates existing both individually and in combination. Decomposition experiments were carried out under hydrogen (10% H2/Ar), helium (He), low oxygen (0.1% O2/He), and excess oxygen (10% O2/He). The structure and composition of the model catalysts were examined before and after the decomposition reactions via powder X-ray diffraction and elemental sulfur analysis. The study revealed that individual alumina-supported aluminum sulfate decomposed at a higher temperature compared to individual alumina-supported palladium sulfate. The simultaneous presence of aluminum and palladium sulfates on the alumina support decreased their decomposition temperatures and led to a higher amount of metallic palladium than in the corresponding case of individual supported palladium sulfate. From a fundamental point of view, the lowest decomposition temperature was achieved in the presence of hydrogen gas, which is the optimal decomposition atmosphere among the studied conditions. In summary, aluminum sulfate has a two-fold role in the regeneration of a catalyst—it decreases the Pd sulfate decomposition temperature and hinders re-oxidation of less-active metallic palladium to active palladium oxide.

Could Biomass Derived Fuels Bridge the Emissions Gap between High Speed Rail and Aviation?

Aviation is a steadily growing sector, which largely contributes to transport greenhouse gas (GHG) emissions. When High Speed Rail (HSR) and aviation are considered as alternative options, HSR proves to be a more environmentally friendly mode of transport. Public available data have been used in order to calculate the emission profiles on two selected intra-European routes (London–Paris and Frankfurt–Amsterdam) by HSR and air. As expected, the air mode results in higher GHG emissions and solutions for mitigating its impact have been analyzed and suggested. Biomass Derived Fuels (BDF) has a limited, up to now, potential, to fill the existing gap in terms of emissions with rail. Moreover, BDF reduction in GHG emissions is accompanied with by an increase in fuel cost. Finally, the cost per tonne of avoided CO2e by using BDF—which values 186 €/t—has been compared with the prices of the European Union (EU) Emission Trading System (ETS) allowances and, from a purely economic perspective, this market based measure still seems a preferable option to curb the GHG emissions of the air mode.

Charging Drivers by the Pound: How Does the UK Vehicle Tax System Affect CO2 Emissions?

Policymakers have been considering vehicle and fuel taxes to reduce transportation greenhouse gas emissions, but there is little evidence on the relative efficacy of these approaches. We examine an annual vehicle registration tax, the vehicle excise duty (VED), which is based on carbon emissions rates. The UK first adopted the system in 2001 and made substantial changes to it in the following years. Using a highly disaggregated dataset at the trim-variant level of UK registrations and characteristics of new cars, we estimate the effect of the VED on new vehicle registrations and their carbon emissions. The VED increased the adoption of low-emissions vehicles and discouraged the purchase of very polluting vehicles, but it had a small effect on aggregate emissions. Using the empirical estimates, we compare the VED with two hypothetical taxes: a tax proportional to carbon emissions per kilometer, and a carbon tax. The VED reduces total emissions from new cars twice as much as the emissions rate tax but by half as much as the emissions tax. Much of the advantage of the emissions tax arises from adjustments in miles driven, rather than the composition of the new car sales.