Dissertations / Theses on the topic 'Vehicle fleet emissions'

Road transport is responsible for a significant share of the global GHG emissions. In order to address the increasing trend of road vehicle emissions, due to its heavy reliance on oil, Nordic countries have set ambitious goals and policies for the reduction of road transport GHG emissions. Despite the fact that the latest developments in the passenger car segment are leading towards the progressive electrification of the fleet, the decarbonization of heavy-duty vehicle segment presents significant challenges that are yet to be overcome. This study focuses, on the first part, on the regulatory framework of fuel economy standards of road vehicles, highlighting the absence of a European regulation on fuel efficiency for the heavy-duty sector. Energy efficiency technologies can be grouped mainly in vehicle technologies, driveline and powertrain technologies, and alternative fuels. The fuel efficiency of HDVs can be positively improved at different vehicle levels, but the technology benefit and its economic feasibility are heavily dependent on the vehicle type and the operational cycle considered. The electrification pathway has the potential of reducing the carbon emission to a great extent, but the current battery technologies have proven to be not cost efficient for the heavy vehicles, because of the high purchase price and the low range, related to the battery cost and inferior energy density compared to conventional liquid fuels.   A scenario development model has been created in order to estimate and quantify the impact of future developments and emission reduction measures in Finland, Sweden and Norway for the timeframe 2016-2050, with a focus on 2030 results. Two scenarios concerning the powertrain developments of heavy-duty vehicles and buses have been created, a conservative scenario and electric scenario, as well as vehicle efficiency improvements and fuel consumption scenarios. Additional sets of parameters have been estimated as input for the model, such as national transport need and load assumptions. The results highlight the challenges of achieving the national GHG emission reduction targets with the current measures in all three countries. The slow fleet renewal rates and the high forecasted increase of transport need limit the benefits of alternative and more efficient powertrains introduced in the fleet by new vehicles. The heavy-duty transport is expected to maintain its heavy reliance on diesel fuel and hinder the improvements of the light-duty segments. A holistic approach is needed to reduce the GHG emissions from road transport, including more efficient powertrains, higher biofuel shares and progressive electrification.

Thesis (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program, 2001.
Includes bibliographical references (leaves 66-68).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Greenhouse gases, such as carbon dioxide, trap solar heat in the atmosphere, raising its temperature. While comprising only about 5% of global population, the U.S. is responsible for nearly one fourth of global annual CO2 emissions. Transportation accounts for a third of all carbon dioxide emissions in the country, and about one fourth worldwide. U.S. passenger cars and light trucks accounting for nearly two thirds of the net carbon equivalent emissions from transportation, any successful national strategy to reduce greenhouse gas emissions would need to address transportation sector emissions. Building upon a vehicle technology assessment conducted at MIT ("On the Road in 2020", Weiss et al., 2000), this study assesses the potential for reducing the U.S. light duty vehicle fleet fuel consumption and energy use. The vehicles technologies considered are an evolving gasoline-fueled baseline vehicle with steadily decreasing fuel consumption, and a gasoline internal combustion engine hybrid vehicle with an advanced body design. Using a vehicle fleet turnover model, the impact on the light-duty fleet of various technology penetration scenarios is assessed. The effects of other factors including the light-duty vehicle stock growth, the increasing per-vehicle annual distance traveled and the sales share of light-duty trucks are evaluated as well. The reduction of new vehicle fuel consumption achieved on the evolving baseline and advanced ICE-Hybrids vehicles provides the most significant savings in fleet energy use over all the other considered measures. Actions aiming at reducing the stock and the total distance traveled growth rate appear to have significant effects on fleet fuel consumption as well, while an increasing share of light-duty trucks will have only a modest impact. Finally, various policy options are discussed. Actions will need to be taken by the Federal Government and the other stakeholders if significant petroleum and greenhouse gas emissions reductions are to be achieved.
by Stéphane Bassène.
S.M.

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 74-78).
In the summer of 2008, the United States of America experienced an oil shock, first of a kind since 1970s. The American public became sensitized to the concerns about foreign oil supply and climate change and global warming, and to the role of transportation in emissions of carbon dioxide and other greenhouse gases (GHG). Several proposed federal policies impose stringent limits on the transportation sector, in terms of fuel consumption and GHG emissions. Within transportation sector, light duty vehicles (LDVs) - cars, light trucks and SUVs - currently emit the most GHGs. Hybrid technology emerged as a promising option to address several of these challenges. A modern hybrid electric vehicle (HEV) offers significantly better fuel economy together with lower levels of pollutant and CO2 emissions. HEVs are currently categorized as Advanced Technology Partial Zero Emission Vehicles (AT-PZEV) by California Air Resource Board. Recently, a new generation of vehicles, plug-in hybrid electric vehicles (PHEV), has been announced in the immediate future by major auto manufacturers. While HEVs have a relatively small battery that is recharged by the engine or by regenerative braking, a larger battery of a PHEV and a charger allows a vehicle owner to recharge the battery from the electric grid. The plug-in technology further increases fuel economy and reduces emissions from the tailpipe. For example, a Chevrolet Volt PHEV is expected to be launched as 2011 model with 40 mile allelectric travel with no tailpipe emissions. However, there are multiple challenges associated with the new technology. HEVs and PHEVs incur higher costs due to additional components, such as electric motors and motor controllers, and a battery. Today's batteries provide energy storage density hundred times lower than that of gasoline. Electricity consumed by hybrids is generated by coal and other fossil fuel power plants that emit harmful chemicals and greenhouse gases. The infrastructure for electric cars is at the infancy stage. Some government policies designed to introduce all-electric cars, such as the California ZEV mandate of the late 1990s, failed to introduce a sustained number of electric vehicles to the market. To provide an integrated approach to the causes and effects of electrified powertrains, two plausible scenarios of advanced vehicle market penetration were developed. Federal policies and consumer preferences were considered as primary drivers. Biofuels were considered alongside fossil fuels as primary energy sources for transportation. Rapid adoption of PHEVs was found to cause a perceptible, but not a significant increase in electric power demand. The scenarios demonstrated ability to achieve fuel economy milestones and quantified the challenge of achieving 80% reduction in greenhouse gas emissions by 2050.
by Michael Khusid.
S.M.in Engineering and Management

Emissions from light-duty passenger vehicles represent a significant portion of total criteria pollutant emissions in the United States. Since the 1970s, emissions testing of these vehicles has been required in many major metropolitan areas, including Atlanta, GA, that were designated to be in non-attainment for one or more of the National Ambient Air Quality Standards. While emissions inspections have successfully reduced emissions by identifying and repairing high emitting vehicles, they have been increasingly inefficient as emissions control systems have become more durable and fewer vehicles are in need of repair. Currently, only about 9% of Atlanta area vehicles fail emissions inspection, but every vehicle is inspected annually. This research addresses explores ways to create a more efficient emissions testing program while continuing to use existing testing infrastructure. To achieve this objective, on road vehicle emissions data were collected as a part of the Continuous Atlanta Fleet Evaluation program sponsored the Georgia Department of Natural Resources. These remote sensing data were combined with in-program vehicle inspection data from the Atlanta Vehicle Inspection and Maintenance (I/M) program to establish the degree to which on road vehicle remote sensing could be used to enhance program efficiency. Based on this analysis, a multi-parameter model was developed to predict the probability of a particular vehicle failing an emissions inspection. The parameters found to influence the probability of failure include: vehicle characteristics, ownership history, vehicle usage, previous emission test results, and remote sensing emissions readings. This model was the foundation for a proposed emissions testing program that would create variable timing for vehicle retesting with high and low failure probability vehicles being more and less frequently, respectively, than the current annual cycle. Implementation of this program is estimated to reduce fleet emissions of 17% for carbon monoxide, 11% for hydrocarbons, and 5% for nitrogen oxides in Atlanta. These reductions would be achieved very cost-effectively at an estimated marginal cost of $149, $7,576 and $2,436 per-ton-per-year for carbon monoxide, hydrocarbons, and nitrogen oxides emissions reductions respectfully.

Motor vehicles are a major source of gaseous and particulate matter pollution in urban areas, particularly of ultrafine sized particles (diameters < 0.1 µm). Exposure to particulate matter has been found to be associated with serious health effects, including respiratory and cardiovascular disease, and mortality. Particle emissions generated by motor vehicles span a very broad size range (from around 0.003-10 µm) and are measured as different subsets of particle mass concentrations or particle number count. However, there exist scientific challenges in analysing and interpreting the large data sets on motor vehicle emission factors, and no understanding is available of the application of different particle metrics as a basis for air quality regulation. To date a comprehensive inventory covering the broad size range of particles emitted by motor vehicles, and which includes particle number, does not exist anywhere in the world. This thesis covers research related to four important and interrelated aspects pertaining to particulate matter generated by motor vehicle fleets. These include the derivation of suitable particle emission factors for use in transport modelling and health impact assessments; quantification of motor vehicle particle emission inventories; investigation of the particle characteristic modality within particle size distributions as a potential for developing air quality regulation; and review and synthesis of current knowledge on ultrafine particles as it relates to motor vehicles; and the application of these aspects to the quantification, control and management of motor vehicle particle emissions. In order to quantify emissions in terms of a comprehensive inventory, which covers the full size range of particles emitted by motor vehicle fleets, it was necessary to derive a suitable set of particle emission factors for different vehicle and road type combinations for particle number, particle volume, PM1, PM2.5 and PM1 (mass concentration of particles with aerodynamic diameters < 1 µm, < 2.5 µm and < 10 µm respectively). The very large data set of emission factors analysed in this study were sourced from measurement studies conducted in developed countries, and hence the derived set of emission factors are suitable for preparing inventories in other urban regions of the developed world. These emission factors are particularly useful for regions with a lack of measurement data to derive emission factors, or where experimental data are available but are of insufficient scope. The comprehensive particle emissions inventory presented in this thesis is the first published inventory of tailpipe particle emissions prepared for a motor vehicle fleet, and included the quantification of particle emissions covering the full size range of particles emitted by vehicles, based on measurement data. The inventory quantified particle emissions measured in terms of particle number and different particle mass size fractions. It was developed for the urban South-East Queensland fleet in Australia, and included testing the particle emission implications of future scenarios for different passenger and freight travel demand. The thesis also presents evidence of the usefulness of examining modality within particle size distributions as a basis for developing air quality regulations; and finds evidence to support the relevance of introducing a new PM1 mass ambient air quality standard for the majority of environments worldwide. The study found that a combination of PM1 and PM10 standards are likely to be a more discerning and suitable set of ambient air quality standards for controlling particles emitted from combustion and mechanically-generated sources, such as motor vehicles, than the current mass standards of PM2.5 and PM10. The study also reviewed and synthesized existing knowledge on ultrafine particles, with a specific focus on those originating from motor vehicles. It found that motor vehicles are significant contributors to both air pollution and ultrafine particles in urban areas, and that a standardized measurement procedure is not currently available for ultrafine particles. The review found discrepancies exist between outcomes of instrumentation used to measure ultrafine particles; that few data is available on ultrafine particle chemistry and composition, long term monitoring; characterization of their spatial and temporal distribution in urban areas; and that no inventories for particle number are available for motor vehicle fleets. This knowledge is critical for epidemiological studies and exposure-response assessment. Conclusions from this review included the recommendation that ultrafine particles in populated urban areas be considered a likely target for future air quality regulation based on particle number, due to their potential impacts on the environment. The research in this PhD thesis successfully integrated the elements needed to quantify and manage motor vehicle fleet emissions, and its novelty relates to the combining of expertise from two distinctly separate disciplines - from aerosol science and transport modelling. The new knowledge and concepts developed in this PhD research provide never before available data and methods which can be used to develop comprehensive, size-resolved inventories of motor vehicle particle emissions, and air quality regulations to control particle emissions to protect the health and well-being of current and future generations.

Motor vehicles are a major source of gaseous and particulate matter pollution in urban areas, particularly of ultrafine sized particles (diameters < 0.1 µm). Exposure to particulate matter has been found to be associated with serious health effects, including respiratory and cardiovascular disease, and mortality. Particle emissions generated by motor vehicles span a very broad size range (from around 0.003-10 µm) and are measured as different subsets of particle mass concentrations or particle number count. However, there exist scientific challenges in analysing and interpreting the large data sets on motor vehicle emission factors, and no understanding is available of the application of different particle metrics as a basis for air quality regulation. To date a comprehensive inventory covering the broad size range of particles emitted by motor vehicles, and which includes particle number, does not exist anywhere in the world. This thesis covers research related to four important and interrelated aspects pertaining to particulate matter generated by motor vehicle fleets. These include the derivation of suitable particle emission factors for use in transport modelling and health impact assessments; quantification of motor vehicle particle emission inventories; investigation of the particle characteristic modality within particle size distributions as a potential for developing air quality regulation; and review and synthesis of current knowledge on ultrafine particles as it relates to motor vehicles; and the application of these aspects to the quantification, control and management of motor vehicle particle emissions. In order to quantify emissions in terms of a comprehensive inventory, which covers the full size range of particles emitted by motor vehicle fleets, it was necessary to derive a suitable set of particle emission factors for different vehicle and road type combinations for particle number, particle volume, PM1, PM2.5 and PM1 (mass concentration of particles with aerodynamic diameters < 1 µm, < 2.5 µm and < 10 µm respectively). The very large data set of emission factors analysed in this study were sourced from measurement studies conducted in developed countries, and hence the derived set of emission factors are suitable for preparing inventories in other urban regions of the developed world. These emission factors are particularly useful for regions with a lack of measurement data to derive emission factors, or where experimental data are available but are of insufficient scope. The comprehensive particle emissions inventory presented in this thesis is the first published inventory of tailpipe particle emissions prepared for a motor vehicle fleet, and included the quantification of particle emissions covering the full size range of particles emitted by vehicles, based on measurement data. The inventory quantified particle emissions measured in terms of particle number and different particle mass size fractions. It was developed for the urban South-East Queensland fleet in Australia, and included testing the particle emission implications of future scenarios for different passenger and freight travel demand. The thesis also presents evidence of the usefulness of examining modality within particle size distributions as a basis for developing air quality regulations; and finds evidence to support the relevance of introducing a new PM1 mass ambient air quality standard for the majority of environments worldwide. The study found that a combination of PM1 and PM10 standards are likely to be a more discerning and suitable set of ambient air quality standards for controlling particles emitted from combustion and mechanically-generated sources, such as motor vehicles, than the current mass standards of PM2.5 and PM10. The study also reviewed and synthesized existing knowledge on ultrafine particles, with a specific focus on those originating from motor vehicles. It found that motor vehicles are significant contributors to both air pollution and ultrafine particles in urban areas, and that a standardized measurement procedure is not currently available for ultrafine particles. The review found discrepancies exist between outcomes of instrumentation used to measure ultrafine particles; that few data is available on ultrafine particle chemistry and composition, long term monitoring; characterization of their spatial and temporal distribution in urban areas; and that no inventories for particle number are available for motor vehicle fleets. This knowledge is critical for epidemiological studies and exposure-response assessment. Conclusions from this review included the recommendation that ultrafine particles in populated urban areas be considered a likely target for future air quality regulation based on particle number, due to their potential impacts on the environment. The research in this PhD thesis successfully integrated the elements needed to quantify and manage motor vehicle fleet emissions, and its novelty relates to the combining of expertise from two distinctly separate disciplines - from aerosol science and transport modelling. The new knowledge and concepts developed in this PhD research provide never before available data and methods which can be used to develop comprehensive, size-resolved inventories of motor vehicle particle emissions, and air quality regulations to control particle emissions to protect the health and well-being of current and future generations.

This doctoral thesis analyses whether electric vehicle is technical, economic and environmental sustainable. We have studied a company fleet of electric vehicles which has a carsharing service for the retail department to know if the EV could replace an internal combustion engine vehicle. We have examined the journeys of 8 EV located on six of the main cities of Spain through data collected from the CAN bus UCV (on-board diagnostics). We have measured the battery's charging, because we are interested on its behaviour (autonomy, auto-discharging and aging) and the energy required to charge the EV. Also, we have studied the well to wheels analysis, assessing their efficiency and environmental effects (CO2 emissions and noise), quantifying the economic impact (fuel and Total Cost of Ownership) and other potential benefits associated with EV (Corporate Social Responsibility, tax free, etc).
Esta tesis analiza si el vehículo eléctrico es sostenible técnica, económica y ambientalmente y puede sustituir a un vehículo de combustión interna, estudiando la flota de vehículos eléctricos de una empresa que tiene un servicio de carsharing contratado para el desplazamiento de sus comerciales. Para ello, se han examinado los trayectos de ocho vehículos eléctricos en seis ciudades españolas a través de los datos obtenidos de su CAN bus mediante el UCV (equipo embarcado) durante los años 2012 y 2013. Además, se han realizado medidas de la carga de la batería, para conocer su comportamiento (autonomía, autodescarga y envejecimiento) y sus consumos energéticos. El objetivo es estudiar su ciclo de vida, valorando su eficiencia y efectos ambientales (emisiones de CO2 y ruido), y concluir cuantificando su impacto económico (combustibles y coste total de la propiedad) y otras posibles ventajas asociadas al vehículo eléctrico (responsabilidad social corporativa, exención de impuestos, etc).

Energy efficiency within the transport sector - A case study on the vehicle fleet of a companyIsak EklövThe environmental objective of zero net emissions of greenhouse gases by 2045 asdecided by the Swedish parliament establishes a framework for a standard thatimplies a demand for considerable changes within many sectors at both technical and political level. The need for long term efficiency solutions with respect tosustainability to be able to reach this goal is great and one step towards this couldpotentially be an adaption to an increased amount of vehicles with alternative fuelsin the vehicle fleet of Sweden. This thesis examined the potential for companiesto reduce their life-cycle emissions of greenhouse gases as well as the total cost ofownership (TCO) for their vehicles by changing the composition of their vehiclefleet.The project started with a literature review of a general character where data forlife-cycle emissions of greenhouse gases as well as TCO for different vehicle typeswas examined and collected. Then the life-cycle emissions of greenhouse gases andTCO were calculated for the different vehicle types through a case study on thevehicle fleet of a company. Finally a programming script was developed to increasethe efficiency of the process which was then used to create scenarios with differentcompositions of the vehicle fleet. A sensitivity analysis was also carried out to evaluate the robustness of the life cycle calculations where the parameters individuallywere altered and the effect on the final result was examined.The result of the case study showed that alternative fueled vehicles are expected tolead to lower life-cycle emissions of greenhouse gases compared to the conventionalalternatives for all vehicle types where alternative fuels are commercially available.The only exception for this was the electric fringe benefit vehicle with a 100 kWhbattery which was expected to lead to higher life-cycle emissions than its fossilalternatives. The result of the cost analysis showed a similar pattern but in thiscase the service vehicle fueled with gas was expected to lead to a higher value ofTCO than its fossil alternatives. The sensitivity analysis for life-cycle emissionsof greenhouse gases showed that production of lithium-ion batteries, vehicle base production and tailpipe emissions were the most contributing parameters forfringe benefit vehicles. The purchase cost was found to be the most contributingparameter for TCO.The result of the scenario analysis showed that there is a potential to decreaseiiilife-cycle emissions of greenhouse gases by 22 % of the total life-cycle emissionsfor the vehicle fleet according to the Base-case scenario. The potential to decreaseTCO was found to be 1,1 %. The other scenarios showed a potential decrease forlife-cycle emissions of 37 % and a cost decrease of 7 % individually.Key words: greenhouse gas emissions, alternative fuels, electric vehicles, totalcost of ownership, life cycle assessment, sustainable vehicle fleet

Making the transition to a ‘green’ vehicle fleet is a noteworthy endeavour for any policy maker. Under the current global pressures of increasing greenhouse gas emissions there is no doubt that all efforts that can be adopted in order to improve the sustainability of our cities should be explored. In saying this however, it is crucial when designing such policies that proper cost-benefit analyses are performed; taking into account the potentially negative rebound effects of such measures and understanding which individuals are affected by such policies. Comprising of two papers, this thesis analyses the choice and usage effects of an exemption for low-emission vehicles (LEVs) from Stockholm’s congestion charging scheme. The ambition of this study has been to understand: the extent to which this exemption policy influenced the demand for LEVs; which individuals were targeted; whether the policy led to any rebound effects (increased LEV usage); and ultimately what the effect of this policy was in terms of changes in emissions. Paper I employs a MNL model to examine the demographics of those individuals who purchased an LEV in Stockholm during 2008 and the extent to which the exemption policy influenced this demand. It was found that those owners living within the cordon but who commuted across the boundary for work had the highest propensity towards purchasing an exempt LEV. The exemption policy was found to have increased the share of exempt LEVs by 1.9% to 18.9% in total, corresponding to an additional 550 exempt LEV purchases in 2008 due to this policy. In Paper II, the differences in annual usage rates between demographically-similar LEV and conventional vehicle owners are calculated using propensity score matching in order to control for potential self-selection effects. Through this procedure it was found that the direct emissions of vehicle owners who adopted LEVs were reduced by 52.4%. Although the exemption policy was partially responsible for increasing the number of LEVs, it also appears to have encouraged an increase in annual usage, leading to rebound effects that offset the potential reduction in emissions (increase in LEV usage: 12.2% for owners that lived inside / worked outside cordon; 8.5% for owners that lived outside / worked inside cordon). Through the analysis detailed in the two papers of this thesis, the effects of an incentive based policy in Stockholm upon both the demand and usage of LEVs have been highlighted. The benefits, as well as the possible complications of this initiative have also been discussed, in the hope of enlightening policy makers to ensure that potential emissions reductions are maximised for similar policy initiatives in the future. With personal vehicles likely to continue dominating the share of home-work trips over the coming years, cities must continue their efforts in encouraging the transition to a ‘green’ vehicle fleet. It is important, however, that these efforts lead to incentive based policies that are balanced, reasonable, and designed to minimise potentially substantial rebound effects.
Övergången till en ”grön” fordonsflotta är en betydelsefull strävan för samtliga beslutsfattare. När de globala utsläppen av växthusgaser ständigt ökar råder det ingen tvekan om att samtliga åtgärder som kan bidra till en hållbar utveckling bör implementeras. Vid utformandet av sådana åtgärder är det dock viktigt ordentliga kostnads-nyttoanalyser utförs, så att hänsyn tas till potentiellt negativa "rebound" och förestålse fås för vilka individer som påverkas. I två artiklar analyserar denna avhandling effekterna på val och användning av ett undantag för fordon med låga utsläpp (LEV) från Stockholms trängselskatt system. Ambitionen med denna studie har varit att förstå: i vilken utsträckning detta undantag i politik påverkade efterfrågan på LEVs, vilka personer som den riktade sig till, om politiken lett till några "rebound" effekter (ökad LEV användning), och slutligen vad effekten var i termer av utsläpp. Artikel I använder en MNL modell för att undersöka demografin av de personer som köpt en LEV i Stockholm under 2008 samt i vilken utsträckning undantaget påverkade denna efterfrågan. Det konstaterades att de ägare som bor inom avspärrningen men som pendlade över gränsen hade den högsta benägenheten att köpa en undantagen LEV. Undantagen från tränselskatt visade sig ha haft en väsentlig inverkan på efterfrågan på undantagna LEVs, andelen av dessa fordon ökade med 1,9%  till 18,9% totalt eller ytterligare 550 LEV inköp under 2008. I artikel II beräknas skillnaderna i årlig användning mellan LEV och konventionella fordon med demografiskt liknande ägare genom "propensity score matching" i syfte att kontrollera för potentiell självselektion. Genom detta förfarande fanns de direkta utsläppen från fordonsägare som övergått till en LEV ha minskat med 52,4%. Även om undantaget från tränselskatt var delvis ansvarigt för att öka antalet LEVs verkar det också ha uppmuntrat en ökad årlig användning, vilket ledde till "rebound" effekter som motverkade den potentiella utsläppsminskningen (ökning i LEV användning för ägare som åkte över gränsen var 12,2% för dem som levde inom och 8,5 % för dem som bodde utanför). I denna avhandling har effekterna av en incitament baserad politik i Stockholm på både efterfrågan och användning av LEVs lyfts fram. Fördelarna liksom de möjliga komplikationerna av detta initiativ har också diskuterats i hopp om att upplysa beslutsfattare så att de potentiella utsläppsminskningarna från liknande politiska initiativ i framtiden kan maximeras. Personliga fordon kommer sannolikt fortsatt dominera andelen hem-arbete resor under de kommande åren och det är därför nödvändigt att städerna fortsäter sina ansträngningar förberömvärd att uppmuntra övergången till en "grön" fordonsflotta. Det är dock viktigt att dessa ansträngningar leder till incitament baserad politik som är balanserad, rimlig och utformade för att minimera de potentiellt betydande "rebound" effekter.

QC 20131025

[EN] The automotive industry is currently experiencing one of its most rapidly changing periods in recent decades, driven by a growing interest in reducing the negative environmental impacts caused by fossil fuels consumption and the resulting carbon dioxide (CO2) emissions generated during the operation of the internal combustion engine (ICE) which have proven to contribute significantly to Global Warming. Given the fact that a total replacement of the current fleet, dependent of fossil fuels, is unlikely to happen in the immediate future and the urgency to reducing CO2 emissions from transportation in order to tackle Global Warming, it is possible to say that optimizing current ICE technologies and conventional vehicles and engines is a first order priority. Among the technical solutions developed to improve the efficiency of ICE, low viscosity engine oils (LVEO) have emerged as an effective and low-cost method that provides reductions in fuel consumption between 0.5% and 5%. During the development of this thesis, a test plan focused on determining fuel consumption reduction when low viscosity oils are used in light duty vehicles (LDV) and heavy duty vehicles (HDV) were carried out. The test plan has been divided in three parts; the first part was focused on the study of light-duty vehicles (LDV) using one diesel engine representative of the European market. During this part three testing modes were used: comparative motored, fired stationary points and transient homologation cycle tests. All test were performed in the engine test bed. The second part of the study consisted of another comparative test, this time using a different engine oils in a HDV fleet. The study was conducted using the urban buses fleet of the city of Valencia, including 3 buses models , with 2 different powertrain technologies. The third part of the study was focused on the friction coefficient behavior within the engine tribological pairs making comparative tests in two specialized tribometers; one of reciprocating action to simulate the lubrication conditions in the piston ring-cylinder liner contact and a "ball-on-disk" tribometer to simulate the lubrication in the distribution system. The various comparative studies have served to analyze how the friction and fuel consumption responded when LVEO were used both in the ICE and the complete vehicle contexts. The fuel consumption benefit found during the test was used to calculate the carbon footprint reduction when LVEO were used.
[ES] Actualmente la industria de la automoción vive uno de los periodos de cambio más vertiginosos de las últimas décadas, marcado por un creciente interés en reducir los impactos medioambientales negativos generados por el consumo de combustibles fósiles y sus consecuentes emisiones nocivas de dioxido de carbono (CO2) generados durante el funcionamiento del motor de combustión interna alternativo (MCIA). Teniendo en cuenta que el proceso de sustitución de la flota actual por una totalmente independiente de los combustibles fósiles puede tomar varias décadas, y ante la urgencia inmediata de reducir las emisiones de CO2, se puede decir que actualmente es más urgente hacer una optimización de los vehículos con motorizaciones convencionales. Entre las soluciones técnicas que se han desarrollado para mejorar la eficiencia del MCIA destaca la utilización de aceites de baja viscosidad como un método efectivo y de bajo coste de implementación que brinda reducciones del consumo entre el 0.5% y el 5%. Durante el desarrollo de esta tesis se ha llevado a cabo un plan de ensayos enfocado en determinar valores concretos de ahorro de combustible esperados cuando se utilizan aceites de baja viscosidad en vehículos de trabajo ligero y pesado. El plan de estudios se dividió en tres partes; la primera se centró en el estudio de MCIA de vehículos de trabajo ligero, utilizando un motor Diesel representativo del mercado Europeo y llevando a cabo pruebas comparativas en arrastre, puntos de funcionamiento estacionarios y ciclos transitorios de homologación. La segunda parte del estudio consta de otro ensayo comparativo, esta vez utilizando una flota de vehículos de trabajo pesado. El estudio se realizó con la flota de autobuses urbanos de la ciudad de Valencia, incluyéndose 3 modelos de autobuses, con 2 tipos de motorización diferente. La tercera parte del estudio se centró en el comportamiento del coeficiente de friction en los pares tribológicos del motor haciendo ensayos comparativos con tribómetros especializados; uno de movimiento alternativo para simular las condiciones de la interfaz piston-camisa y un "bola y disco" para simular la lubricación en el sistema de distribución, específicamente en la interfaz leva-taqué. Los diversos estudios comparativos han servido para analizar como es la respuesta general de la fricción y el consumo de combustible cuando se usan aceites de baja viscosidad, tanto a nivel de motor como para la totalidad del vehículo, encontrando diferencias de par en los ensayos de arrastre, de consumo específico de combustible en los ensayos de motor en estado estacionario y diferencias totales de consumo de combustible en los ensayos en régimen transitorio y en flota, que a su vez han permitido estimar la reducción esperada en la huella de carbono.
[CAT] Actualment la indústria de l'automoció viu un dels períodes de canvi més vertiginoses de les últimes dècades, marcat per un creixent interès en reduir els impactes mediambientals negatius generats pel consum de combustibles fòssils i els seus conseqüents emissions nocives de diòxid de carboni (CO2) generats durant el funcionament del motor de combustió interna alternatiu (MCIA). Tenint en compte que el procés de substitució de la flota actual per una totalment independent dels combustibles fòssils pot prendre diverses dècades, i davant la urgència immediata de reduir les emissions de CO2, es pot dir que actualment és més urgent fer una optimització dels vehicles amb motoritzacions convencionals. Entre les solucions tècniques que s'han desenvolupat per millorar l'eficiència del MCIA destaca la utilització d'olis de baixa viscositat com un mètode efectiu i de baix cost d'implementació que brinda reduccions del consum entre el 0.5% i el 5%. Durant el desenvolupament d'aquesta tesi s'ha dut a terme un pla d'assajos enfocat a determinar valors concrets d'estalvi de combustible esperats quan s'utilitzen olis de baixa viscositat en vehicles de treball lleuger i pesat. El pla d'estudis es va dividir en tres parts; la primera es va centrar en l'estudi de MCIA de vehicles de treball lleuger, utilitzant un motor dièsel representatiu del mercat Europeu i portant a terme proves comparatives en arrossegament, punts de funcionament estacionaris i cicles transitoris d'homologació. la segona part de l'estudi consta d'un altre assaig comparatiu, aquest cop utilitzant una flota de vehicles de treball pesat. L'estudi es va realitzar amb la flota d'autobusos urbans de la ciutat de València, incloent-se 3 models d'autobusos, amb 2 tipus de motorització diferent. La tercera part de l'estudi es va centrar en el comportament del coeficient de friction en els parells tribològics del motor fent assajos comparatius amb tribómetros especialitzats; Un acció reciprocante per simular les condicions del piston camisa i un bola i disc per simular la lubricació en el sistema de distribució. Els diversos estudis comparatius han servit per analitzar com és la resposta general de la fricció i el consum de combustible quan es fan servir olis de baixa viscositat, tant a nivell de motor com la totalitat del vehicle, trobant diferències de bat a els assajos d'arrossegament, de consum específic de combustible en els assajos de motor en estat estacionari i diferències totals de consum de combustible en els assajos en règim transitori i en flota, que al seu torn han permès calcular la reducció en la petjada de carbono.
Ramírez Roa, LA. (2016). Contribution to the Assessment of the Potential of Low Viscosity Engine Oils to Reduce ICE Fuel Consumption and CO2 Emissions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73068
TESIS

Ocorrem anualmente aproximadamente 600.000 mortes de crianças com até cinco anos, no mundo. Pneumonia é a principal causa e mais de 50 por cento destas mortes são atribuídas à poluição do ar. Ela ainda é responsável pelo aumento do risco de infecções respiratórias, asma, condições neonatais adversas e anomalias congênitas. A poluição do ar também afeta o desenvolvimento cognitivo de crianças e induz o desenvolvimento de doenças crônicas na idade adulta. Entre 70 e 80 por cento da poluição do ar em nações em desenvolvimento são de origem veicular. Objetivando definir critérios baseados em medições com sensoriamento remoto para identificação de veículos automotores leves do ciclo Otto com elevadas emissões de monóxido de carbono, hidrocarbonetos ou óxido nítrico, foram utilizados os dados secundários gerados pela Remote Sensing do Brasil Ltda dos quais foram selecionados 179.142 veículos em uso da frota circulante da cidade de São Paulo com medições completas dos índices de emissão dos poluentes monóxido de carbono (CO), hidrocarbonetos (HC) e óxido nítrico (NO) e ainda velocidade e aceleração do veículo quando da medição e inclinação da pista no local escolhido para as medições. Foram ajustados modelos estatísticos da classe Generalised Additive Models for Location, Scale and Shape (GAMLSS) visando testar a influência do Tipo de Combustível, da Potência Específica do Veículo (VSP) e das Fases do Programa de Controle da Poluição do Ar por Veículos Automotores (Proconve) sobre as emissões de CO, HC e NO, medidos usando o Remote Sensing Device (RSD). As emissões foram então conceitualmente subdivididas em dois grupos: veículos com emissões normais e com emissões anormais, isso para os diversos poluentes em veículos das Fases L3, L4 e L5 que são as fases de interesse para o gerenciamento da qualidade do ar. Variáveis latentes foram definidas para indicarem as distribuições dos veículos em relação a esses grupos e Fases. O algoritmo Expectation-Maximization (EM) foi empregado para identificação dos parâmetros das distribuições. Para determinação dos valores associados aos veículos com elevadas emissões de determinado poluente e fase do Proconve, foi empregado o percentil 98 por cento da distribuição ajustada para os veículos dos grupos com emissões normais. Assim sendo, o Erro de Tipo I foi fixado em 2 por cento sendo que esse percentual foi estabelecido considerando o Erro de Tipo II, de apontar o veículo como tendo emissão normal quando na realidade trata-se de um high emitter. Através desta abordagem foram determinados os valores indicativos de veículos com elevadas emissões segundo o poluente e a Fase do Proconve. Os resultados apontaram decréscimo nas emissões de CO e de HC segundo as Fases do Proconve. Para o NO, o comportamento das emissões não acompanhou as reduções impostas pelas Fases do Proconve. Foi constatado que os veículos de 2005 a 2009, movidos exclusivamente a gasool, foram os que apresentaram as maiores emissões de NO. Diversos possíveis fatores causadores deste comportamento diferenciado do NO foram discutidos neste trabalho. Os dados de qualidade do ar detectaram aumento significativo nas concentrações ambientais de Óxidos de Nitrogênio (NOx) em 2007, quando foi monitorado este parâmetro no período de inverno, o que pode indicar a influência dos high emitters, mas necessita de estudos mais aprofundados para confirmação da causa deste comportamento.
Approximately 600,000 deaths occur worldwide annually for children up to five years of age. Pneumonia is the leading cause and more than 50 per cent of these deaths are attributed to air pollution. It is still responsible for increased risk of respiratory infections, asthma, adverse neonatal conditions and congenital anomalies. Air pollution also affects the cognitive development of children and induces future development of chronic diseases in adulthood. In order to define criteria based on remote sensing measurements to identify Otto cycle light duty vehicles (LDV) with high emissions of carbon monoxide, hydrocarbons or nitric oxide it was used secondary data produced by Remote Sensing do Brasil Ltda, from which 179,142 inuse vehicles were selected, that belongs to the city of São Paulos current fleet. All those vehicles had complete measurements of emission of carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO), and also speed and acceleration of the vehicle during measurements, and slope of the track at the place chosen for the measurements. Statistical models of the Generalized Additive Models for Location, Scale and Shape (GAMLSS) class were adjusted to test the influence of fuel type, Vehicle Specific Power (VSP) and of the Brazilian Vehicle Emission Control Program [Proconve] phases on CO, HC and NO emissions, measured using Remote Sensing Device (RSD). The emissions were then conceptually subdivided into two groups: vehicles with normal and abnormal emission, for the various pollutants in vehicles of L3, L4 and L5 phases of Proconve, which were of interest for the air quality management. Latent variables were defined to indicate the distribution of vehicles in relation to those groups and phases. The algorithm Expectation Maximization (EM) was employed to identify all parameters of the distributions. We use the 98 per cent percentiles of the statistical distribution set, for vehicles of groups with normal emissions to determine the limit values for vehicles with high emissions of pollutants and Proconve Phase. Therefore, the Type I Error was set at 2 per cent and this percentage was established considering the Type II Error to point the vehicle as having normal emission when in fact it is a high emitter. Through this approach, the indicative values of vehicles with high emissions according to the pollutant and the Proconve Phase were determined. Results of emissions measured with the RSD technique indicated a decrease in CO and HC emissions according to the Proconve Phase. For the NO, the emissions behavior did not follow the reductions imposed by the Proconve Phases. It was found that newer vehicles year model from 2005 to 2009 exclusively gasohol-powered vehicles, were the ones that presented the highest NO emissions. Several possible causative factors of this differential behavior of NO were discussed in this study. A significant increase in the environmental concentrations of Nitrogen Oxides (NOx) was detected in 2007, when this parameter was monitored in the winter period. This may indicate the influence of the high emitter vehicles, but it requires a more in-depth cause-effect study for confirmation of this behavior.

abstract: Mobile sources emit a number of different gases including nitrogen oxides (NOx) and volatile organic compounds (VOCs) as well as particulate matter (PM10, PM2.5). As a result, mobile sources are major contributors to urban air pollution and can be the dominant source of some local air pollution problems. In general, mobile sources are divided into two categories: on-road mobile sources and non-road mobile sources. In Maricopa County, the Maricopa County Air Quality Department prepares inventories of all local sources [11], [12]. These inventories report that for Maricopa County, on-road mobile sources emit about 23% of total PM2.5 annually, 58% of the total NOx, and 8% of the total VOCs. To understand how future changes how vehicles might impact local air quality, this work focuses on comparing current inventories of PM2.5, black carbon (BC), NOx, and VOCs to what may be expected emissions in future years based on different scenarios of penetration of hybrid gas-electric vehicles (HEV) and electric vehicles (EV) as well as continued reduction in emissions from conventional internal combustion (IC) vehicles. A range of scenarios has been developed as part of this thesis based on literature reports [6], [8], air quality improvement plan documentation [5], projected vehicle sales and registration [3], [4], as well as using EPA’s Motor Vehicle Emission Simulator (MOVES) [9]. Thus, these created scenarios can be used to evaluate what factors will make the most significant difference in improving local air quality through reduced emissions of PM2.5, BC, NOx and VOCs in the future. Specifically, the impact of a greater fraction of cleaner alternative vehicles such as hybrid-electric and electric vehicles will be compared to the impact of continual reductions in emissions from traditional internal combustion vehicles to reducing urban air pollution emissions in Maricopa County.
Dissertation/Thesis
Masters Thesis Civil, Environmental and Sustainable Engineering 2020

In today’s world of volatile fuel prices and climate concerns, there is little study on the relation between vehicle ownership patterns and attitudes toward potential policies and vehicle technologies. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin’s household-fleet evolution. Results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are vehicle purchase price, type/class, and fuel economy (with 30%, 21% and 19% of respondents placing these in their top three). Most (56%) respondents also indicated that they would seriously consider purchasing a Plug-In Hybrid Electric Vehicle (PHEV) if it were to cost $6,000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle’s emissions, more strongly than they respond to information on fuel cost savings. 25-year simulations suggest that 19% of Austin’s vehicle fleet could be comprised of Hybrid Electric Vehicles (HEVs) and PHEVs under adoption of a feebate policy (along with PHEV availability in Year 1 of the simulation, and current gas prices throughout). Under all scenarios vehicle usage levels (in total vehicle miles traveled [VMT]) are predicted to increase overall, along with average vehicle ownership levels (per household, and per capita); and a feebate policy is predicted to raise total regional VMT slightly (just 4.43 percent, by simulation year 25), relative to the trend scenario, while reducing CO2 emissions only slightly (by 3.8 percent, relative to trend). Doubling the trend-case gas price to $5/gallon is simulated to reduce the year-25 vehicle use levels by 17% and CO2 emissions by 22% (relative to trend). Two- and three-vehicle households are simulated to be the highest adopters of HEVs and PHEVs across all scenarios. And HEVs, PHEVs and Smart Cars are estimated to represent a major share of the fleet’s VMT (25%) by year 25 under the feebate scenario. The combined share of vans, pickup trucks, sport utility vehicles (SUVs), and cross over utility vehicles (CUVs) is lowest under the feebate scenario, at 35% (versus 47% in Austin’s current household fleet), yet feebate-policy receipts exceed rebates in each simulation year. A 15% reduction in the usage levels of SUVs, CUVs and minivans is observed in the $5/gallon scenario (relative to trend). Mean use levels per vehicle of HEVs and PHEVs are simulated to have a variation of 753 and 495 across scenarios. In the longer term, gas price dynamics, tax incentives, feebates and purchase prices along with new technologies, government-industry partnerships, and more accurate information on range and recharging times (which increase customer confidence in EV technologies) should have even more significant effects on energy dependence and greenhouse gas emissions.
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The first part of this thesis relies on stated and revealed preference survey results across a sample of U.S. households to first ascertain vehicle acquisition, disposal, and use patterns, and then simulate these for a synthetic population over time. Results include predictions of future U.S. household-fleet composition, use, and greenhouse gas (GHG) emissions under nine different scenarios, including variations in fuel and plug-in-electric-vehicle (PHEV) prices, new-vehicle feebate policies, and land-use-density settings. The adoption and widespread use of plug-in vehicles will depend on thoughtful marketing, competitive pricing, government incentives, reliable driving-range reports, and adequate charging infrastructure. This work highlights the impacts of various directions consumers may head with such vehicles. For example, twenty-five-year simulations at gas prices at $7 per gallon resulted in the highest market share predictions (16.30%) for PHEVs, HEVs, and Smart Cars (combined) — and the greatest GHG-emissions reductions. Predictions under the two feebate policy scenarios suggest shifts toward fuel-efficient vehicles, but with vehicle miles traveled (VMT) rising slightly (by 0.96% and 1.42%), thanks to lower driving costs. The stricter of the two feebate policies – coupled with gasoline at $5 per gallon – resulted in the highest market share (16.37%) for PHEVs, HEVs, and Smart Cars, but not as much GHG emissions reduction as the $7 gas price scenario. Total VMT values under the two feebate scenarios and low-PHEV-pricing scenarios were higher than those under the trend scenario (by 0.56%, 0.96%, and 1.42%, respectively), but only the low-PHEV-pricing scenario delivered higher overall GHG emission estimates (just 0.23% more than trend) in year 2035. The high-density scenario (where job and household densities were quadrupled) resulted in the lowest total vehicle ownership levels, along with below-trend VMT and emissions rates. Finally, the scenario involving a $7,500 rebate on all PHEVs still predicted lower PHEV market share than the $7 gas price scenario (i.e., 2.85% rather than 3.78%). The second part of this thesis relies on data from the U.S. Consumer Expenditure Survey (CEX) to estimate the welfare impacts of carbon taxes and household-level capping of emissions (with carbon-credit trading allowed). A translog utility framework was calibrated and then used to anticipate household expenditures across nine consumer goods categories, including vehicle usage and vehicle expenses. An input-output model was used to estimate the impact of carbon pricing on goods prices, and a vehicle choice model determined vehicle type preferences, along with each household’s effective travel costs. Behaviors were predicted under two carbon tax scenarios ($50 per ton and $100 per ton of CO2-equivalents) and four cap-and-trade scenarios (10-ton and 15-ton cap per person per year with trading allowed at $50 per ton and $100 per ton carbon price). Results suggest that low-income households respond the most under a $100-per-ton tax but increase GHG emissions under cap-and-trade scenarios, thanks to increased income via sale of their carbon credits. High-income households respond the most across all the scenarios under a 10-ton cap (per household member, per year) and trading at $100 per ton scenario. Highest overall emission reduction (47.2%) was estimated to be under $100 per ton carbon tax. High welfare loss was predicted for all households (to the order of 20% of household income) under both the policies. Results suggest that a carbon tax will be regressive (in terms of taxes paid per dollar of expenditure), but a tax-revenue redistribution can be used to offset this regressivity. In the absence of substitution opportunities (within each of the nine expenditure categories), these results represent highly conservative (worst-case) results, but they illuminate the behavioral response trends while providing a rigorous framework for future work.
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The shift to strong hybrid and electrified vehicle architectures engenders controversy and brings about many unanswered questions. It is unclear whether developed markets will have the infrastructure in place to support and successfully implement them. To date, limited effort has been made to comprehend if the energy and transportation solutions that work well for one city or geographic region may extend broadly. A region's capacity to supply a fleet of EVs, or plug-in hybrid vehicles with the required charging infrastructure, does not necessarily make such vehicle architectures an optimal solution. In this study, a mix of technologies ranging from HEV to PHEV and EREV through to Battery Electric Vehicles were analyzed and set in three Canadian Provinces and 3 U.S. Regions for the year 2020. Government agency developed environmental software tools were used to estimate greenhouse gas emissions and energy use. Projected vehicle technology shares were employed to estimate regional environmental implications. Alternative vehicle technologies and fuels are recommended for each region based on local power generation schemes.
UOIT

碩士
國立成功大學
工業與資訊管理學系
107
With the booming of e-commerce, the demand for delivery has gradually increased. Delivery operators want to enhance competitiveness and reduce transportation costs. Therefore, there is a new model called Feeder Vehicle Routing Problem (FVRP), which is the extension of VRP. It mainly uses the cooperation of trucks and motorcycles to carry out delivery service. When motorcycles are out of commodity, it can directly find trucks for reloading. This reloading method can reduce overall travel costs and speed up delivery efficiency. Besides, as air pollution problems become more severe, the restrictions on carbon emission become stricter, which is a challenge for delivery operators. Therefore, this thesis adds carbon emission and electric motorcycle considerations, and proposes a Heterogeneous Fleet Feeder Vehicle Routing Problem Considering Carbon Emission (EFVRP). Then formulate a mathematical model and proposes a simulated annealing (SA) method for solving EFVRP. The objective of EFVRP is to minimize the total cost consisting of travel cost, carbon penalty cost, and fixed vehicle cost. The problem was solved by the optimization software Gurobi and the SA method respectively. The results show that SA is outperforming than Gurobi. For sensitivity analysis, the carbon emission penalty cost of motorcycle and the travel cost of an electric motorcycle is not significant.

Tese de doutoramento em Sistemas Sustentáveis de Energia, apresentada ao Departamento de Engenharia Mecânica da Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Electric vehicles (EVs) have been promoted as an alternative to reduce greenhouse gas (GHG) emissions, fossil fuel dependence, and urban pollution caused by the transportation sector; however, a large scale adoption of EVs faces significant challenges. A number of studies have assessed the effects of EVs in the electricity system and the environmental impacts of different scenarios of evolution of the transportation sector. However, few studies integrating both electricity and fleet displacement effects have been performed. A dynamic fleet-based life-cycle perspective is thus necessary to understand the consequences and determine the extent to which the introduction of EVs in the fleet can actually reduce rather than simply shift environmental impacts of personal transport. This thesis presents a dynamic fleet-based life-cycle framework to assess the effects on environmental impacts of the introduction of EVs in a fleet. The framework combines fleet analysis and dynamic life-cycle modelling of vehicles to investigate the displacement of conventional vehicles over time, and consequential life-cycle assessment of electricity to assess the changes induced in the electricity system due to EV charging. The analysis focused on the case of introducing battery electric vehicles (BEVs) in the Portuguese light-duty fleet and focused on GHG emissions. A comprehensive life-cycle assessment of electricity generation and supply in Portugal was also performed to identify the main drivers of impacts, how impacts change over time, and how charging time influences BEV GHG emissions. Reducing fleet-wide GHG emissions by displacing internal combustion engine vehicles (ICEVs) by BEVs in Portugal depends mostly on the GHG intensity of the Portuguese electricity system, on the degree of reduction in fuel consumption of new ICEVs, and on the level of penetration of BEVs. In order to achieve significant reductions compared to an increasingly more efficient ICEV fleet, a high BEV market share and electricity GHG intensity similar or lower to the current mix (485 g CO2 eq kWh-1) need to be realized. The response of the electricity system to BEV demand, regarding the changes in electricity generation by the various sources and corresponding GHG emissions, may thus determine the benefits of BEVs over conventional technologies. Electricity GHG emissions in Portugal vary significantly between years and throughout the year. As a result of the temporal variability in electricity generation and, in particular, in the marginal supply, the time of charging can have a major influence on the GHG benefits of ii BEVs. What has been considered, in general, the most favorable charging time from the economic and operation of the electricity system perspective (off-peak hours), may not be so from an environmental standpoint. In Portugal, simply encouraging charging during the night may increase emissions from the electricity system as a result of the fossil-based marginal electricity supply (mostly coal). Therefore, charging control strategies should ensure that surplus renewable energy use by BEVs is maximized so that environmental impacts can be reduced. However, interactions with other strategies to enable renewable energy sources, such as electricity storage, may be important and should be accounted for. When the electricity system includes significant storage of energy, for instance through pumped hydro storage (PHS), the effects of introducing BEVs go beyond the straightforward displacement of ICEVs and increase in electricity demand, to include significant indirect effects from the dynamics of storage. Such indirect effects may decrease or even offset the GHG benefits of ICEV displacement. However, the net effects on GHG emissions are very dependent on the technologies displaced both by PHS and by BEVs, so that detailed analysis is needed for any specific energy system, allowing for future technological improvements. The dynamic fleet-based life-cycle framework developed in this thesis provides a comprehensive environmental assessment of the adoption of a new technology, because it enables explicit assessment of changes in technologies and background systems over time in a fleet perspective, as well as indirect effects related to the existing system. In particular, this framework can be used to assess the effects on environmental impacts of other electricity-using products in a fleet perspective, and of measures that improve the energy efficiency of end-use applications or that shift the use of electricity. The change-oriented approach pursued can also aid in understanding the consequences of policies and strategies that enable and promote the use of electricity over other fuels.
Os veículos elétricos (EVs) têm sido apontados como alternativa para reduzir as emissões de gases com efeito de estufa (GEE), a dependência de combustíveis fósseis e a poluição em meio urbano causadas pelo sector dos transportes, mas a sua adoção enfrenta importantes desafios. Vários estudos avaliaram os efeitos dos EVs no sistema elétrico e os impactes ambientais de diferentes cenários de evolução do setor dos transportes, mas poucos analisaram em conjunto os efeitos ambientais sobre o sistema elétrico e aqueles relativos à substituição de veículos de combustão interna (VCIs). Deste modo, para perceber as consequências e determinar se a introdução de EVs na frota reduz efetivamente os impactes ambientais associados ao transporte individual ou se apenas os transferem para outras partes do sistema é necessário adotar uma perspetiva dinâmica de ciclo de vida (CV). Esta tese apresenta uma abordagem dinâmica de CV com base em modelos de frota para avaliar os efeitos ambientais da introdução de EVs numa frota. A abordagem combina análise de frotas e modelação dinâmica de CV de veículos com o objetivo de avaliar os efeitos da substituição de VCIs por EVs ao longo do tempo, e avaliação consequencial de CV de sistemas elétricos para avaliar as alterações induzidas no sistema elétrico devido ao carregamento dos EVs. A análise incidiu sobre a introdução de EVs a baterias (BEVs) no parque automóvel ligeiro português e focou-se na avaliação das emissões de GEE. Foi ainda realizada uma avaliação abrangente de CV da geração de eletricidade em Portugal com o objetivo de identificar os fatores que mais contribuem para os impactes, de que forma variam os impactes ao longo do tempo e qual a influência do horário de carregamento nas emissões de GEE dos BEVs. A redução total das emissões de GEE da frota automóvel em resultado da substituição de VCIs por BEVs em Portugal depende da intensidade de GEE do sistema elétrico português, do grau de redução no consumo de combustível dos novos VCIs e no nível de penetração de BEVs. De modo a alcançar reduções significativas em comparação com uma frota de VCIs cada vez mais eficientes, é necessário que a quota de mercado dos BEVs seja alta e que a intensidade de GEE do sistema elétrico seja inferior ou semelhante à atual (485 g CO2 eq kWh-1). A resposta do sistema elétrico à procura dos BEVs, relativamente à variação na geração de eletricidade pelas várias fontes e correspondente variação nas emissões de GEE, determina os benefícios dos BEVs relativamente aos VCIs. iv As emissões de GEE da eletricidade em Portugal variam significativamente de ano para ano e ao longo do ano. Devido à variabilidade temporal na geração de eletricidade e, em particular, na geração marginal, o horário de carregamento tem uma grande influência nas emissões de GEE causadas pelos BEVs. Aquele que tem sido considerado, em geral, o período mais favorável para o seu carregamento do ponto de vista da operação do sistema elétrico (horas de vazio), pode não o ser do ponto de vista da redução dos impactes ambientais. Em Portugal, incentivar o carregamento durante a noite pode resultar num aumento das emissões do sistema elétrico, uma vez que a tecnologia marginal é na maioria do tempo carvão. Deste modo, as estratégias de controlo dos carregamentos devem ser implementadas de forma a garantir a maximização da utilização da energia renovável em excesso para reduzir os impactes ambientais. No entanto, é preciso ter em conta a interação entre os BEVs e outras estratégias de utilização de energia renovável intermitente, como é o caso dos sistemas de armazenamento de eletricidade. Quando o sistema elétrico permite o armazenamento de quantidades significativas de eletricidade, por exemplo através de barragens hidroelétricas com sistemas de bombagem, os efeitos da introdução de BEVs vão além da simples substituição de VCIs e aumento da procura por eletricidade, para incluir efeitos indiretos significativos associados à dinâmica de armazenamento. Tais efeitos podem diminuir ou mesmo anular os benefícios em termos de emissões de GEE associados à substituição de VCIs. No entanto, o efeito líquido sobre as emissões de GEE depende muito das tecnologias substituídas tanto pelos BEVs como pelos sistemas de armazenamento, pelo que é necessário efetuar uma análise detalhada para cada sistema energético, tendo em conta melhorias tecnológicas futuras. A abordagem desenvolvida nesta tese permite avaliar de forma integrada os impactes ambientais causados pela adoção de uma nova tecnologia, uma vez que possibilita avaliar explicitamente alterações no sistema ao longo do tempo bem como efeitos indiretos. Em particular, a abordagem desenvolvida pode ser usada para avaliar os efeitos ambientais de outros produtos que consomem eletricidade numa perspetiva de frota, bem como de medidas para melhorar a eficiência energética. A abordagem consequencial implementada permite ainda ajudar a compreender as consequências de políticas e estratégias que promovam a utilização de eletricidade em substituição de outros combustíveis.
FCT - SFRH/BD/51299/2010

The U.S. Environmental Protection Agency introduced Carbon Dioxide emission standards for Light-Duty-Vehicles, accounting for emissions associated to electric vehicles for the first time. This affects the incentives of manufacturers like AUDI to comply with the regulations. The purpose of this work is to contribute to a better understanding of the environmental implications of such regulations measured by the estimated total emissions. Therefore, a sensitivity analysis with respect to the most influential parameters is performed. Further, this work provides an indication of the real world CO2 emission savings potential of the regulatory framework, by examining different manufacturer’s compliance strategies.

Transportation fleet emissions have a dominant role in air quality because of their significant contribution to ozone precursor and greenhouse gas emissions. Regulatory policies have emphasized improvements in vehicle fuel economy, alternative fuel use, and engine and vehicle technologies as approaches for obtaining transportation systems that support sustainable development. This study examined the air quality impacts of the partial electrification of the transportation fleet and the use of biofuels for the Austin Metropolitan Statistical Area under a 2030 vision of regional population growth and urban development using the Comprehensive Air Quality Model with extensions (CAMx). Different strategies were considered including the use of Plug-in Hybrid Electric Vehicles (PHEVs) with nighttime charging using excess capacity from electricity generation units and the replacement of conventional petroleum fuels with different percentages of the biofuels E85 and B100 along or in combination. Comparisons between a 2030 regional vision of growth assuming a continuation of current development trends (denoted as Envision Central Texas A or ECT A) in the Austin MSA and the electrification and biofuels scenarios were evaluated using different metrics, including changes in daily maximum 1-hour and 8-hour ozone concentrations, total area, time integrated area and total daily population exposure exceeding different 1-hour ozone concentration thresholds. Changes in ozone precursor emissions and predicted carbon monoxide and aldehyde concentrations were also determined for each scenario. Maximum changes in hourly ozone concentration from the use of PHEVs ranged from -8.5 to 2.2 ppb relative to ECT A. Replacement of petroleum based fuels with E85 had a lesser effect than PHEVs on maximum daily ozone concentrations. The maximum reduction due to replacement of 100% of gasoline fuel in light and heavy duty gasoline vehicles by E85 ranged from -2.1 to 2.8 ppb. The magnitude of the effect was sensitive to the biofuel penetration level. Unlike E85, B100 negatively impacted hourly ozone concentrations relative to the 2030 ECT A case. As the replacement level of petroleum-diesel fuel with B100 in diesel vehicles increased, hourly ozone concentrations increased as well. However, changes due to the penetration of B100 were relatively smaller than those due to E85 since the gasoline fraction of the fleet is larger than the diesel fraction. Because of the reductions in NOx emissions associated with E85, the results for the biofuels combination scenario were similar to those for the E85 scenario. Also, the results showed that as the threshold ozone concentration increased, so too did the percentage reductions in total daily population exposure for the PHEV, E85, and biofuel combination scenarios relative to ECT A. The greatest reductions in population exposure under higher threshold ozone concentrations were achieved with the E85 100% and 17% PHEV with EGU controls scenarios, while the B100 scenarios resulted in greater population exposure under higher threshold ozone concentrations.
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