In Europe, diesel combustion is being banned due to the NOx and PM2.5 emissions impact on air quality. The bus sector is being electrified and is increasing its use of alternative fuels, such as natural gas (in spark ignition engines) and bioethanol (in compression ignition engines), to reduce such harmful emissions. Even if a diesel bus is equipped with selective catalytic reduction (SCR), its NOx emissions are reduced its but produces more NH3 emissions that are PM2.5 precursors. In developing countries, the air quality is still barely monitored, however, the air quality issue is well known and is being addressed. Moreover, the Ecuadorian sugar cane industry is seeking ways to increase its ethanol production. This is the ideal framework to explore a new technology and energy source in developing economies such as Ecuador. This paper explores the impact of the Ecuadorian diesel bus fleet conversion to hybrid compression ignition ethanol (HEV-ED95), hybrid diesel and plug-in hybrid flex-fuel using electricity and internal combustion engine ICE-E20 and ICE-E100. The impacts are measured in terms of final energy consumption, criteria pollutant emissions (NH3, NOx, PM2.5) and 100 years global warming potential in a well-to-wheels framework. For the tank-to-wheels data the method follows the typical values of conversion efficiency from final to useful energy (cross checked with a microsimulation model), the Tier 2 European Environmental Agency approach combined with ethanol influence on compression ratio, lower heating value, criteria emissions taken from a literature review, and well-to-tank emission factors for electricity (10–58% thermal natural gas or coal powerplant contribution), for ethanol from banana industry wastes (ED95, E20 and E100), gasoline and diesel from US databases. A discussion on whether sugarcane biorefineries are necessary is highlighted in the results. All input parameters have an uncertainty range between a minimum and a maximum and the probability for each is giving by a uniform distribution.
Climate change is a serious threat to sustainability. Anthropogenic climate change is due to the accumulation of greenhouse gases (GHG) in the atmosphere beyond natural levels. Anthropogenic GHG emissions are mostly associated with carbon-dioxide (CO2) originated in the combustion of fossil fuels used for heat, power, and transportation. Globally, transportation contributes to 14% of the global GHG emissions. The transport sector is one of the main contributors to the greenhouse gas emissions of Ecuador. In Guayaquil, the road mass transportation system comprises regular buses and the bus rapid transit (BRT) system. Electricity in Ecuador is mostly derived from hydropower, hence incurs relatively low GHG emissions along its life cycle. Therefore, electrification of transport has been seen as an opportunity for mitigation of GHG emissions. In this study, the effect of partial replacement of the bus rapid system fleet is investigated. Feeders have been chosen as the replacement target in five different scenarios. GHG emissions from diesel-based feeders have been calculated using the GREET Fleet Footprint Calculator tool. The GHG emissions associated with the electricity used for transportation is calculated using the life cycle inventory of the electricity generation system of Ecuador. Three energy mix scenarios are used for this purpose. The 2012 mix which had 61% hydropower; the mix of 85% hydropower and the marginal electricity scenario, which supposed the extreme case when the new demand for electricity occurs during peak demand periods. Results indicate that mitigation of GHG emissions is possible for almost all scenarios of percentage fleet replacement and all mix scenarios. Electric buses efficiency and the carbon intensity of the electricity mix are critical for GHG mitigation.
Systematical Analysis of the Impacts of different operations conditions and geological formation characteristics on Area of Review (AoR), Post Injection Site Care (PISC) and Risk associated with anthropogenic CO2 Sequestration in Citronelle Dome, Alabama Danilo Arcentales Bastidas Dedication This thesis is dedicated to all my family who have made everything in life so that I could achieve all my goals, for all the motivation, guidance and trust that I received from them at any time. A special dedication to my grandfather who passed away during this time. iii Acknowledgements First, I would like to express a deepest and infinite thank to my advisor, Dr. Ebrahim Fathi, for all his help, guidance and commitment throughout my research. I would like to express my gratitude for his spirit of adventure regarding research during this work.
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Major concerns of carbon dioxide (CO2) sequestration in subsurface formations are knowledge of the well injectivity and gas storage capacity of the formation, the CO2 pressure and saturation plume extensions during and after injection, and the risks associated with CO2 leakage and fault reactivation. Saline reservoirs are considered as one of the target formations for CO2 sequestration through structural, residual, dissolution, and mineral trapping mechanisms. The boundary condition of the saline reservoir dictates the pressure and saturation plume extension of the injected supercritical CO2 that could expand over large distances. This can lead to sources of risk, e.g., leakage and/or fault reactivation due to presence of wells, thief zones, and geological discontinuities. Therefore, there is a critical need to develop a model that describes how risk-related performance metrics (i.e., the CO2 saturation plume size, the pressure differential plume area, and the pressure differential at specific locations) vary as a function of the size of injection, time following injection, injection operations, and geologic environment. In this study, a systematic reservoir modeling studies of anthropogenic CO2 sequestration in Citronelle dome, Alabama, was performed where all relevant scenarios and conditions to address the questions of the saturation and pressure plume size in the area of review (AoR) and post-injection site care (PISC) are considered. The objective for this study was firstly to systematically simulate CO2 sequestration, i.e., saturation dynamics, and pressure behavior over a range of operational and geological conditions and to derive conclusions about the factors influencing saturation and pressure plume size, post-injection behavior, and the risk associated with them, by developing third-generation reduced order models (ROMs) for reservoir behavior. Finally, to assess the uncertainty associated with our studies, Latin Hypercube Sampling (LHS) together with an experimental design technique, i.e., Plackett–Burman design, was used. Application of Pareto charts and respond surfaces enabled us to determine the most important parameters impacting saturation and pressure plume sizes and to quantify the auto- and cross-correlation among different parameters in both history-matched and upscaled models.
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