abstract: Fossil fuel CO2 (FFCO2) emissions are recognized as the dominant greenhouse gas driving climate change (Enting et. al., 1995; Conway et al., 1994; Francey et al., 1995; Bousquet et. al., 1999). Transportation is a major component of FFCO2 emissions, especially in urban areas. An improved understanding of on-road FFCO2 emission at high spatial resolution is essential to both carbon science and mitigation policy. Though considerable research has been accomplished within a few high-income portions of the planet such as the United States and Western Europe, little work has attempted to comprehensively quantify high-resolution on-road FFCO2 emissions globally. Key questions for such a global quantification are: (1) What are the driving factors for on-road FFCO2 emissions? (2) How robust are the relationships? and (3) How do on-road FFCO2 emissions vary with urban form at fine spatial scales? This study used urban form/socio-economic data combined with self-reported on-road FFCO2 emissions for a sample of global cities to estimate relationships within a multivariate regression framework based on an adjusted STIRPAT model. The on-road high-resolution (whole-city) regression FFCO2 model robustness was evaluated by introducing artificial error, conducting cross-validation, and assessing relationship sensitivity under various model specifications. Results indicated that fuel economy, vehicle ownership, road density and population density were statistically significant factors that correlate with on-road FFCO2 emissions. Of these four variables, fuel economy and vehicle ownership had the most robust relationships. A second regression model was constructed to examine the relationship between global on-road FFCO2 emissions and urban form factors (described by population ii density, road density, and distance to activity centers) at sub-city spatial scales (1 km2). Results showed that: 1) Road density is the most significant (p<2.66e-037) predictor of on-road FFCO2 emissions at the 1 km2 spatial scale; 2) The correlation between population density and on-road FFCO2 emissions for interstates/freeways varies little by city type. For arterials, on-road FFCO2 emissions show a stronger relationship to population density in clustered cities (slope = 0.24) than dispersed cities (slope = 0.13). FFCO2 3) The distance to activity centers has a significant positive relationship with on-road FFCO2 emission for the interstate and freeway toad types, but an insignificant relationship with the arterial road type. / Dissertation/Thesis / Doctoral Dissertation Environmental Social Science 2018

Maintenance of power plants is aimed at extending the life and reducing the risk of sudden breakdown of power generating units. Traditionally, power generating units have been scheduled for maintenance in periods to ensure that the demand of the system is fully met and the reliability of the system is maximized. However, in a deregulated power industry, the pressure of maintaining generating units is also driven by the potential revenue received by participating in the electricity market. Ideally, hydropower generating units are required to operate during periods when electricity prices are high and to be able to be taken offline for maintenance when the price is low. Therefore, determination of the optimum time periods for maintenance of generating units in a power system has become an important task from both a system reliability and an economic point of view. Due to the extremely large number of potential maintenance schedules, a systematic approach is required to ensure that optimal or near-optimal maintenance schedules are obtained within an acceptable timeframe. Metaheustics are high-level algorithmic frameworks that aim to solve combinatorial optimisation problems with a large search space in a reasonable computational run time. Inspired by the foraging behavior of ant colonies, Ant Colony Optimisation (ACO) is a relatively new metaheuristic for combinatorial optimisation. The application of ACO to a number of different applications has provided encouraging results when applied to scheduling, including the job-shop, flow-shop, machine tardiness and resource-constrained project scheduling problems. In this thesis, a formulation is developed that enables ACO to be applied to the generalized power plant maintenance scheduling optimisation (PPMSO) problem. The formulation caters for all constraints generally encountered as part of real-world PPMSO problems, including system demands and reliability levels, precedence rules between maintenance tasks, public holidays and minimum outage durations in the case of shortening of maintenance tasks. As part of the formulation, a new heuristic and a new local search strategy have been developed. The new ACO-PPMSO formulation has been tested extensively on two benchmark PPMSO problems from the literature, including a 21-unit and a 22-unit problem. It was found that the ACOPPMSO formulation resulted in significant improvements in performance for both case studies compared with the results obtained in previous studies. In addition, the new heuristic formulation was found to be useful in finding maintenance schedules that result in more evenly spread reserve capacity and resource allocations. When tested using a modified version of the 21-unit and the 22-unit problems, the new local search strategy specifically designed for duration shortening was found to be effective in searching locally for maintenance schedules that require minimal shortening of outage duration. The ACO-PPMSO formulation was also successfully able to cater for all constraints as specified in both original and the modified versions of the two benchmark case studies. In order to further test the ACO-PPMSO formulation developed, it was first applied to a scaled-down version of the Hydro Tasmania hydropower system (five power stations) and then to the full system (55 generating units). As part of the studies, the ACO-PPMSO formulation was linked with the simulation model used by Hydro Tasmania to assess the impact of various maintenance schedules on the total energy in storage of the system at the end of the planning horizon, the total thermal generation, the total number of days where the reliability level is not met, as well as the total unserved energy throughout the planning horizon. A number of constraints were considered, including the anticipated system demands, a 30% capacity reliability level, the minimum and maximum durations between related maintenance tasks, the precedence constraints and the minimum outage duration of each task in the case of shortening of maintenance tasks. The maintenance schedule was optimised for the maximum end-of-horizon total energy in storage, the minimum thermal generation and the minimum total outage durations shortened and deferred, under 77 different inflow conditions. The optimal maintenance schedule obtained compared favourably with that obtained by Hydro Tasmania over many years based on experience. Specifically, the ACO-PPMSO schedule results in higher end-of-horizon total energy in storage and satisfies both hard and soft constraints, which overall equates to over $0.5 million dollars of savings when compared to the schedule obtained using the practitioners’ experience and engineering judgment. The ACO-PPMSO algorithm was also shown to be a useful decision-making tool for scheduling maintenance under different circumstances when tested with four scenarios commonly encountered in practical maintenance scheduling problems. In conclusion, the ACO-PPMSO formulation developed, tested and applied as part of this thesis research provides a powerful and flexible means of obtaining optimal or near-optimal maintenance schedules for power plants. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294672 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2007

The transport sector is facing great challenges of rising transport demand but at the same time meeting requirements of substituting fossil fuels, and mitigating its environmental impacts. Conventional transportation solutions are well-adapted to urban contexts, but not to rural contexts. A tendency to try to solve rural issues with urban thinking has been observed during the study. The thesis’s purpose is to aid the implementation of the national “Fossil-fuel free 2030” vision in the County of Jämtland, Sweden, by studying fossil fuel use in a well-defined rural area: the island of Norderön in Lake Storsjön. The thesis is based on a literature study, interviews with islanders and officials, and a questionnaire to the islanders.   The transport work for Norderön was estimated in form of annual the fuel use of diesel and petrol. Diesel consumption in 2011, including ferries, was estimated to 500 m3 (c:a 4 m3 per capita and year) and petrol consumption, including through traffic, was estimated to 300 m3 (c:a 2 m3 per capita and year). Annual mileage per car and number of cars per capita on the island are higher than in Sweden in general. The large number of private cars on the island is caused by insufficient public transportation service. A household with low accessibility requires high mobility to satisfy its needs. For the situation in 2030 a probable increase in transport demand is compensated by an increase in energy efficiency of different transport technology, and the fuel consumption is thus estimated to be similar in 2030 to what is was in 2011. Reaching the “Fossil-fuel free 2030” vision through a direct substitution of fossil fuels with bio-based fuels will be limited by biofuel supply, especially if the vision shall be reached also in areas surrounding Norderön. There is an urgent need to develop solutions applicable for rural areas, which are based on comprehensive transport demand management measures combined with continued focus on fuel efficiency, energy efficient transport modes and alternative fuels. / Transportsektorn står inför stora utmaningar genom ökat transportbehov samtidigt som den ska möta krav på bränsleomställning och minskad miljöpåverkan. Konventionella lösningar för hållbart resande är välanpassade för stadsmiljöer, men inte för glesbygd. En tendens att försöka lösa glesbygdens problem med ett stadstänk har observerats under studien.  Uppsatsens syfte är att hjälpa Länsstyrelsen Jämtlands län att implementera visionen Fossilbränslefritt 2030 genom att studera fossilbränsleanvändning i en välavgränsad glesbygd: Norderön i Storsjön. Uppsatsen bygger på en litteraturstudie, intervjuer med öbor och tjänstemän, samt en enkät till öborna.   Dieselförbrukningen, inklusive färjorna, var c:a 500 m3 år 2011 och bensinförbrukningen, inklusive genomfartstrafik, var c:a 300 m3. Körsträcka per bil och bilägande är högre på Norderön än riksgenomsnittet. Ett hushåll med låg tillgänglighet kräver hög rörlighet för att möta sitt behov. En potentiell ökning av transportefterfrågan år 2030 kompenseras av bränslesnålare teknik, och därför antas bränsleförbrukningen vara lika år 2030. Tillgången på biobränsle kommer att begränsa möjligheten att fullständigt ersätta fossila bränslen. Det finns ett påtagligt behov av att utveckla glesbygdslösningar baserade på åtgärder för hållbart resande kombinerat med fortsatt fokus på bränslesnålare teknik och alternativa bränslen. / Projekt Norderön

Fossil fuel combustion produces fly-ash particles that are released into the atmosphere and deposited in the environment. A particularly characteristic kind of fly-ash is spheroidal carbonaceous particles. They are composed of an amorphous carbon matrix in which other elements are dispersed. The elemental carbon content makes them very resistant to chemical degradation and these particles can be relatively easily extracted from sediment and soil samples using a method described in this thesis. The distribution of spheroidal carbonaceous particles in lake sediment profiles, surface sediments and forest soils has been studied. Cores from several Swedish lakes have been analysed and, although the lakes are from different parts of the country, consistent trends in the deposition of the carbonaceous particles have been found. The analyses of dated cores show that the carbonaceous particle deposition in the sediments follows the same general pattern as statistics for Swedish coal and oil combustion over the last two centuries. This indicates that the sediment records reflect the history of the atmospheric deposition of particulate pollutants from fossil fuel combustion. Analysis of surface sediment samples provides an integrated picture of the deposition over the preceding few years and can be used to indicate the contemporary geographical pattern of deposition from the atmosphere. Two sets of surface sediment samples (0-1 cm) were analysed. One comprised samples from 66 lakes around Sweden's second largest city, Gothenburg, and showed very high carbonaceous particle concentrations within a distance of 50 to 100 km from the city. The second set comprised surface sediment samples from 114 lakes distributed all over Sweden. This survey of Sweden demonstrated a geographical north-south gradient with more than a hundred times higher particle concentrations in the south than in the north. This distribution is similar to the distribution of other air pollutants (data obtained from a moss survey and an air monitoring program) and suggests that carbonaceous particles in palaeolimnological investigations of air pollution, can be used as tracers for pollutants that are otherwise difficult to determine in lake sediments. Spheroidal carbonaceous particles also accumulate in soils, and forest soil samples can be used for geographical surveys of particle deposition. In Swedish podzol soils the particles mainly accumulate in the thin organic horizon and concentrations in this layer reflect the total deposition since industrialisation, although most will have been deposited during the last few decades. Since the spheroidal carbonaceous particle record in Swedish lake sediments has a characteristic temporal pattern, carbonaceous particle profiles can be used for indirect dating of recent sediment cores. Analyses of multiple sediment cores from three lakes demonstrate that carbonaceous particles can also be used for studies of sediment distribution in lake basins. Results from Gårdsjön indicate that the acidification of the lake changed sediment distribution processes from a normal sediment focusing regime to a more even distribution of sediments over the lake bottom. Liming of the lake seems to have restored normal sedimentation processes. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1992, Härtill 8 uppsatser</p> / digitalisering@umu

The use of microalgae culture to convert CO2 from power plant flue gases into biomass that are readily converted into biofuels offers a new frame of opportunities to enhance, compliment or replace fossil-fuel-use. Apart from being renewable, microalgae also have the capacity to utilise materials from a variety of wastewater and the ability to yield both liquid and gaseous biofuels. However, the processes of cultivation, incorporation of a production system for power plant waste flue gas use, algae harvesting, and oil extraction from the biomass have many challenges. Using SimaPro software, Life cycle Assessment (LCA) of the challenges limiting the microalgae (Chlorella vulgaris) biofuel production process was performed to study algae-based pathway for producing biofuels. Attention was paid to material use, energy consumed and the environmental burdens associated with the production processes. The goal was to determine the weak spots within the production system and identify changes in particular data-set that can lead to and lower material use, energy consumption and lower environmental impacts than the baseline microalgae biofuel production system. The analysis considered a hypothetical transesterification and Anaerobic Digestion (AD) transformation of algae-to- biofuel process. Life cycle Inventory (LCI) characterisation results of the baseline biodiesel (BD) transesterification scenario indicates that heating to get the biomass to 90% DWB accounts for 64% of the total input energy, while electrical energy and fertilizer obligations represents 19% and 16% respectively. Also, Life Cycle Impact Assessment (LCIA) results of the baseline BD production scenario show high proportional contribution of electricity and heat energy obligations for most impact categories considered relative to other resources. This is attributed to the concentration/drying requirement of algae biomass in order to ease downstream processes of lipid extraction and subsequent transesterification of extracted lipids into BD. Thus, four prospective alternative production scenarios were successfully characterised to evaluate the extent of their impact scenarios on the production system with regards to lowering material use, lower energy consumption and lower environmental burdens than the standard algae biofuel production system. A 55.3% reduction in mineral use obligation was evaluated as the most significant impact reduction due to the integration of 100% recycling of production harvest water for the AD production system. Recycling also saw water demand reduced from 3726 kg (freshwater).kgBD- 1 to 591kg (freshwater).kgBD- 1 after accounting for evaporative losses/biomass drying for the BD transesterification production process. Also, the use of wastewater/sea water as alternative growth media for the BD production system, indicated potential savings of: 4.2 MJ (11.8%) in electricity/heat obligation, 10.7% reductions for climate change impact, and 87% offset in mineral use requirement relative to the baseline production system. Likewise, LCIA characterisation comparison results comparing the baseline production scenarios with that of a set-up with co-product economic allocation consideration show very interesting outcomes. Indicating -12 MJ surplus (-33%) reductions for fossil fuels resource use impact category, 52.7% impact reductions for mineral use impact and 56.6% reductions for land use impact categories relative to the baseline BD production process model. These results show the importance of allocation consideration to LCA as a decision support tool. Overall, process improvements that are needed to optimise economic viability also improve the life cycle environmental impacts or sustainability of the production systems. Results obtained have been observed to agree reasonably with Monte Carlo sensitivity analysis, with the production scenario proposing the exploitation of wastewater/sea water to culture algae biomass offering the best result outcome. This study may have implications for additional resources such as production facility and its construction process, feedstock processing logistics and transport infrastructure which are excluded. Future LCA study will require extensive consideration of these additional resources such as: facility size and its construction, better engineering data for water transfer, combined heat and power plant efficiency estimates and the fate of long-term emissions such as organic nitrogen in the AD digestate. Conclusions were drawn and suggestions proffered for further study.

Thesis (M.S.)--Duquesne University, 2006. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p.72) and index.

Can Battery Electric Vehicles replace conventional internal combustion engine vehicles for commuting purposes when exposed to a busy corporate activity within the city of Edinburgh? This thesis investigates the application of Battery Electric Vehicles (BEV) use in a commercial business environment in the city of Edinburgh, Scotland UK. The motivation behind this work is to determine if the Battery Electric Vehicle can replace conventional fossil fuel vehicles under real world drive cycles and the desire by many to combat the causes of climate change. Due to the nature of this work a significant part of the work will be underpinned by the quantitative methodology approach to the research. As the question indicates the research is supported by real live data coming from the vehicle both in proprietary data logging as well as reading and analysing the data coming from the vehicles own Electronic Control Unit (ECU).There will be mixed research methodology encompassing quantitative and qualitative research to obtain a complete response in respect to the management of the vehicle these methodologies will be the analysis of the measurable data as well as explorative, to gain the underlying reasons and motivations for choosing a battery electric vehicle as an option to the conventional vehicle for this type of application use.

A new IAM is used to calculate the optimal tradeoff between, on the one hand,locking up fossil fuel and curbing global warming, and, on the other hand,sacrificing consumption now and in the near future. This IAM uses the Oxford carbon cycle, which differs from DICE, FUND and PAGE in that cumulative emissions are the key driving force of changes in temperature. We highlight how time impatience, intergenerational inequality aversion and expected trend growth affect the time paths of the optimal global carbon tax and the optimal amount of fossil fuel reserves to leave untapped. We also compare these with the adverse and deleterious global warming trajectories that occur if no policy actions are taken. (authors' abstract) / Series: Ecological Economic Papers

This bachelor thesis asks the question, what does the increased fossil fuel scarcity mean for the Arctic region? It further investigates the aim and motives by the five main Arctic states. With the use of structural realism, existing research on the parallels between resource scarcity and conflict and, the combination of two methodological approaches: quantitative and qualitative content analysis, I argue in this study that the five states will act in accordance with the structural realist way and exploit the Arctic due to the protection of their national interests and security. This thesis highlights that, firstly, there is a process of climate change enabling the accessibility to extracting fossil fuel. Secondly, there is an ongoing militarization of the region. With that being said, I argue that the race for fossil fuel will prevail and this will create a destabilizing Arctic region with environmental impacts and militarization that can lead to problematic disputes and even conflicts. Therefore, the Arctic is a vulnerable region with a questionable future due to its economic stakes and militarization.

No description available.