[pt] O Brasil possui uma já extensa malha offshore de gasodutos e, no desenvolvimento da produção do Pré-Sal, esta deve continuar se expandindo em razão das necessidades de aumento da capacidade de escoamento de gás e também da sua reinjeção nos próprios reservatórios (seja apenas como descarte ou como um método de recuperação avançado). Uma vez instalada, esta malha deve ser periodicamente passar por manutenção, o que implica em eventos esporádicos de esvaziamento destes dutos, normalmente operando a altas pressões. Devido ao custo elevado de tais operações, deve-se estimar com boa precisão o tempo total necessário para despressurização, que pode levar várias horas ou até dias. Além disso, também é importante a previsão do inventário de líquido remanescente nos dutos após a despressurização. No presente trabalho, foi desenvolvido um modelo numérico para prever a despressurização de gasodutos considerando escoamento bifásico homogêneo e unidimensional. A formação e o consumo de condensado é obtida a partir de um inventário inicial de fluido supercrítico, com premissa de equilíbrio entre as fases. As propriedades termodinâmicas dos fluidos são determinadas utilizando-se pacotes comerciais e pré-tabuladas em função de pressão e temperatura. As equações de conservação foram discretizadas pelo método das diferenças finitas, utilizando o método de Euler implícito para o termo temporal e aproximação upwind nas derivadas espaciais. O sistema algébrico resultante foi resolvido diretamente de forma acoplada. Os resultados obtidos mostram boa concordância ao compará-los a dados reais de campo e resultados de simuladores comerciais de referência. / [en] Although Brazilian gas pipeline grid is already quite extensive, it continues to expand due to the Pre Salt development, since there is a growing need to increase the flowing capacity towards onshore facilities and injection wells (gas to be discarded or used for advanced oil recovery). Once pipelines are installed, maintenance operation must be performed quite often to guarantee process efficiency. Usually these operations demand depressurization from very high pressures. Considering the costs involved in such operations it is mandatory to accurately predict the total time for a complete blowdown, which may take several hours or even a couple of days. Furthermore, it is also important to evaluate the condensate content in the pipeline after the depressurization event. In the present work, a numerical model was developed to simulate gas pipeline depressurization considering unidimensional two-phase homogeneous flow. The formation and consumption of condensate from an initial supercritical state is obtained assuming phase equilibrium. Fluid properties are taken from tables generated by PVT packages. Conservation equations are discretized through the finite difference method employing Euler implicit approximation for the time derivatives and upwind scheme for spatial terms. A coupled direct algorithm was adopted to solve the resulting algebraic system. The results are compared to real field data and commercial software showing good agreement.

Agricultural input expenditures have not been widely incorporated in most partial equilibrium models. Thus, investigating the effect of economic policies and other exogenous factors on the agricultural sector will produce only a partial analysis, since the simultaneous impact of these factors on input expenditures is excluded. This study, therefore, extends the existing partial equilibrium multi-market model of the South African agricultural sector (BFAP model) by incorporating agricultural input expenditure. Thus, the analysis of the impact of economic policies on the agricultural sector, which was limited only on the gross income (production, area planted and prices), has now been extended to assess their effects on input expenditures, gross value added and net farming income of the sector. In addition, the analysis is further extended to evaluate the financial and economic position of the agricultural sector by investigating the implications of the policies on the asset and debt values of the sector. The comparative result obtained from the shocks of a crude oil and world fertiliser price rise shows that due to the inclusion of the recursive effect from the output to input side of the sector and vice versa and endogenising input costs, the effect of the shock on gross value added and net farming income converges slowly and cyclically in the recursively linked model, compared to the unlinked model, in which the effect abruptly halts after a single year. Thus, the recursively linked integrated model replicates the dynamics experienced by the agricultural sector better than the recursively unlinked integrated model. In addition, the endogenisation of domestic input costs on the integrated model allows a comprehensive analysis of the effect of macroeconomic variables on the agricultural sector by considering their impact on both outputs and inputs. Thus, using the recursively linked model, a fifty percent devaluation of exchange rate is assessed. The result showed that a depreciation of exchange rate resulted in a net benefit for the sector, as the gain from enhancing agricultural income outweighs the rise in expenditure. Excluding the simultaneous impact on input expenditure would have overestimated the benefit by looking only at its effect on gross income. The integrated model was also used to project a baseline for the South African agricultural sector’s main aggregate variables for the medium term (2010-2015) under the status quo of policy assumptions and forecast values of exogenous variables. The baseline projections of the gross income, intermediate input expenditure and gross value added show a modest average annual growth rate during the baseline period. The net farming income, however, depicts a relatively lower growth due to the general modest rise in agricultural gross income compared with total input expenditure. Based on the projected values of main aggregate variables, several financial and economic performance indicators for the agricultural sector are also projected. In general, the economic performance indicators of the sector, measured by the net return on the sector’s investment and equity, show good performance when compared with the average cost of borrowing during the baseline period. Thus, this study shows that integrating input expenditure in a multi-market output model by recursively linking both sides and endogenising domestic input costs would improve the result of the standard partial equilibrium by generating projections for several key aggregate variables, providing the net effect of economic policies on the agricultural sector and replicating the dynamics of the agricultural sector better than models that have few/no input components or that assess the effects separately and ignore the recursive linkage. Thus, this study provides a powerful modelling tool to be used by policy makers to comprehensively investigate the net effects of economic policies on the agricultural sector and to answer several ‘what if’ questions. / Thesis (DCom)--University of Pretoria, 2010. / Agricultural Economics, Extension and Rural Development / unrestricted

Abstract  Course: NAA305 Bachelor Thesis in Economics 15 ECTS  University: Mälardalen University, School of Business, Society and Engineering, Västerås  Title: The effects of immigration on the income of native-born workers:  Evidence from Sweden Author: Arnold Schanzer-Larsen  Supervisor: Johan Lindén  Problem: Sweden has experienced a lot of immigration, and the phenomenon has received a great deal of attention in the public and political debate. There is, among other things, fear that immigration could be harmful for the labor market outcome of the receiving country. Researchers from a variety of countries have tried to address this issue by estimating the effect of immigration on the native wage of the receiving country. The results have varied strongly and no universal conclusion can be drawn. For what can be said about Sweden, there is no paper (of our knowledge) that has done any similar estimates. For that reason, it is of great importance that there is some research which could bring empirical evidence and shed light on the debate.  Purpose of the Research: The aim of the thesis is to quantitatively measure immigrations effect on the wage of native workers in Sweden. Methodology:  Conducting a panel study, observation of the average native income from 290 municipalities over 2011-2019 was collected. The effect was estimated using OLS regression technique and a fixed effect model.  Conclusion: From a 10% increase in the share of foreign-born within a municipality, led on average to a 2.89% increase in the native average income in that municipality.  Keywords: Immigration, Income, Wage, Unemployment rate, Panel study, Fixed effect model, Native, Labor market, The equilibrium model, Human capital, Skill-composition

L'appel croissant à la mise en œuvre d'une politique climatique ambitieuse et globale devrait détério-rer les perspectives économiques des pays dépendants du pétrole. Cette thèse étudie les impacts économiques de cette transition bas-carbone ainsi que les stratégies d'atténuation possibles pour le premier exportateur de pétrole: le Royaume d'Arabie Saoudite (AS). Nous proposons une applica-tion utilisant un modèle intégré économie-énergie-environnement qui prend en compte les spécifici-tés de l’économie saoudienne comme l’ancrage de son taux de change ou encore les prix d’énergies administrés.Premièrement, en utilisant une représentation agrégée de l’économie saoudienne, nous montrons qu’un prix du pétrole plus faible résultant de la transition bas-carbone mondiale résulte en un taux de croissance marginalement bas, des excédents commerciaux significativement réduits et à un chô-mage plus élevé. Nous analysons la portée des outils dont dispose l’AS pour atténuer les impacts des politiques climatiques sur son économie. Nous estimons que l'alignement des prix de l'énergie saou-diens sur les références internationales ainsi que l’augmentation des gains d'efficacité énergétique fournissent à l’AS des sources de revenus supplémentaires. Ce cadre de modélisation permet de tes-ter des scénarios prospectifs tout en contrôlant leurs spécifications macroéconomiques.Ensuite, nous mettons en perspective ces spécifications dans un cadre multisectoriel afin d'étudier les stratégies de diversification émanant des contributions prévues déterminées au niveau national (INDC) ainsi que son programme stratégique Vision 2030. Nous concluons que la diversification économique dans les secteurs à faible intensité énergétique (industrie manufacturière, tourisme et services financiers) en augmentant les exportations et la substitution des importations, en plus de réformer l'impôt sur les sociétés offre une perspective positive par rapport à une expansion continue des industries à forte intensité énergétique (minéraux, pétrochimie et ciment). En effet, nous mon-trons que la diversification dans les secteurs à faible intensité énergétique génère une croissance plus forte et un chômage plus faible. En outre, dans le cadre de ce scénario de diversification écono-mique, l’AS dépasse ses engagements climatiques en termes de réduction des émissions de CO2. Néanmoins, l’expansion des secteurs à forte intensité énergétique résulte en une meilleure perspec-tive de la dette publique puisque le gouvernement tire des revenus plus élevés de ses participations dans les industries lourdes. Enfin, nous concluons que dans nos deux scénarios, l’AS n’atteint que partiellement ses ambitions de transition vers une économie moins dépendante du pétrole dans le cadre du programme Vision 2030, ce qui suggère que de nouvelles réformes doivent être envisagées.Cette thèse contribue à la littérature sur l’implémentation d’une politique climatique et ses consé-quences économiques pour les pays exportateurs pétrole. Notre travail fournit des estimations sur les réformes économiques à entreprendre comme stratégies d'atténuation et pourrait donc être adapté pour couvrir d'autres pays et sources d’énergie. / The increasing call for implementing a global and ambitious climate policy is expected to deteriorate economic outlook of oil-dependent countries. Our research work investigates the impact of this global low-carbon transition and the potential mitigation strategies for the largest oil exporter: The Kingdom of Saudi Arabia (KSA). We propose an application using an integrated economy-energy-environment modelling framework taking into account salient features of the Saudi economy such as the currency peg and the regulated domestic energy prices.First, using an aggregated representation of the KSA economy, we show that a weaker oil price re-sulting from the global low-carbon transition is associated with a marginally lower growth, large trade surplus accumulation loss, and higher unemployment for the KSA. We analyse what scope the KSA has to mitigate climate policy impacts. We reveal that aligning domestic energy prices with international references and achieving energy efficiency gains increases economic efficiency while improving public budget prospects. This modelling framework allows to investigate scenarios while controlling the modelling macroeconomic specifications.We refine these outlooks in a mulstisector framework that further allows investigating diversifica-tion opportunities within the Saudi Intended Nationally Determined Contribution (INDC) and its Vision 2030 program. We conclude that economic diversification into non energy-intensive sectors (manufacture, tourism, and financial services) through increasing exports and import substitution, in addition to targeting fiscal adjustments of the corporate tax, provide a positive outlook compared with a continuous expansion of energy-intensive activities (minerals, petrochemical, and cement). Indeed, we show that diversification in non-energy intensive sector generates higher growth, and lower unemployment. In addition, under our designed economic diversification plan, the KSA ex-ceeds its climate pledges in terms of targeted CO2 abatement. Nevertheless, the continuous expan-sion of energy-intensive industries is associated with a better outlook for the public debt since the government derives higher revenues from its participation in energy-intensive industries. Finally, we conclude that in our two scenarios, the KSA only partially succeeds in its transition toward a less oil-dependent economy as part of the Vision 2030 program, suggesting that further reforms are to be considered.This thesis contributes to the literature on climate policy implementation and associated economic consequences for fossil-fuel exporters. It provides insights on economic reforms as mitigation strate-gies and could be thus adapted to cover additional countries and fuels.

No description available.

L’objectif de cette thèse consiste à élaborer un modèle d’équilibre général calculable adapté à l’analyse de la politique de soutien au biodiesel en France. Le gouvernement français a décidé récemment de supprimer l’exonération partielle de TICPE qui était jusqu’à présent la principale aide aux biocarburants de première génération. Cette mesure pourrait compromettre l’avenir de ce secteur en l’absence d’un nouveau système d’incitations. Notre modèle vise d’une part à mesurer les conséquences de ce changement réglementaire sur les différentes activités économiques; et d’autre part à évaluer les impacts d’un dispositif alternatif de soutien au biodiesel fondé sur un relèvement de la fiscalité sur le gazole. L’étude tient compte de la contribution des fluctuations du prix du pétrole à cet objectif. La matrice de comptabilité sociale servant de base empirique au modèle est fondée sur l’année de référence 2009. Elle comprend 3 facteurs de production, et 17 biens et secteurs d’activité. La désagrégation des secteurs agricoles et agroalimentaires fait apparaître la chaîne de production du biodiesel de manière détaillée. Le modèle intègre également des spécifications permettant de représenter le rôle des coproduits du biodiesel et les changements d’affectation des sols. Les résultats des simulations suggèrent que l’objectif d’incorporation de 10% à l’horizon 2020 requis par la directive européenne de 2009 pourrait être atteint par un relèvement de la TICPE sur le gazole à un niveau comparable à celui en vigueur sur le carburant essence. Cependant, les effets récessifs observés sur un certain nombre de variables conduisent à tempérer l’opportunité d’adopter une telle mesure. / The objective of this thesis is to build a computable general equilibrium model for the analysis of the public support policy to biodiesel in France. The French government has recently decided to remove the partial exemption from the excise tax on fuels that was until now the main support instrument to promote first-generation biofuels. This modification could affect the profitability of the biofuels’ and connected activities. In this context, our model aims on the one hand to quantifies the consequences of this policy change throughout the national economy; on the other hand, it assesses the impacts of an alternative support scheme based on higher taxes on conventional diesel. The study also takes into account the influence of oil price fluctuations in the analysis. The social accounting matrix (SAM) used as empirical basis is built on the 2009 reference year. It includes three production factors, and seventeen goods and activity sectors. The disaggregation of agricultural and agribusiness sectors emphasizes the whole biodiesel production chain. Energy substitution is reflected through multi-stages nested production and consumption structures. In line with recent studies, the model also specifies the role of biodiesel by-products in the livestock sector, and analyses the land use changes. Different scenarios are implemented to isolate the effects of changes in the support system. Results of simulations suggest that the 10% penetration rate targeted by the 2009 European directive by 2020 could be reached with taxes on diesel as high as on gasoline. However, recessive impacts observed in many sectors mitigate the opportunity to adopt such an alternative support policy.

Dans un contexte de croissance effrénée de la demande mondiale d'énergie et de pression environnementale pour lutter contre le réchauffement climatique, cette thèse étudie une des technologies envisagées pour réduire les émissions de dioxyde de carbone (CO2) : la capture et le stockage géologique du carbone (CSC). Nous étudions principalement l’application de cette technologie à la production des bioénergies (BCSC) car ce procédé permet d’épurer l’atmosphère tout en fournissant un substitut énergétique non polluant aux énergies fossiles. La première partie de ce travail analyse le potentiel économique et environnemental de la technologie de BCSC. Tout d'abord, une évaluation économique et environnementale de la BCSC dans le secteur de la production de bioéthanol en France est conduite.Ensuite, grâce à un modèle bottom-up d’optimisation TIAM-FR, nous étudions le potentiel global et régional de cette technologie dans le secteur de l'électricité. Enfin, les incitations économiques à mettre en place pour assurer son développement sont mises en évidences. Dans la deuxième partie, un modèle d'équilibre général calculable est utilisé pour évaluer les politiques environnementales. Nous construisons le modèle théorique en introduisant les technologies de CSC et de BCSC ainsi qu’une large variété d’instruments économiques. Le modèle est ensuite calibré pour comparer l’efficacité économique des instruments de politique environnementale à un niveau mondial et à un niveau français. / In a context of unbridled growth of global energy demand and environmental pressure in the fight againstglobal warming, this thesis studies one of the proposed technologies to reduce carbon dioxide (CO2)emissions: carbon capture and geological storage (CCS). We therefore consider the application of thistechnology to the production of bioenergies (BCCS) because this technology allows purifying theatmosphere while providing a clean energy alternative to fossil fuels. The first part of this work analyzesthe economic and environmental potential of BCCS. First, an economic and environmental assessment ofBCCS in the bioethanol production in France is conducted. Then, using the bottom-up optimization modelTIAM-FR, we study the global and regional potential of this technology in the electricity sector. Finally,the economic incentives that need to be provided to ensure BCCS deployment are highlighted. In thesecond part, a general equilibrium model is used to evaluate environmental policies. We construct thetheoretical model by introducing the CCS and BCCS as well as a wide range of economic instruments.The model is then calibrated to compare the effectiveness of environmental policy instruments at a globallevel and at a French level.

Près de deux décennies, après la libéralisation de l’économie tunisienne, les disparités régionales se sont fortement accentuées. Les amples écarts de développement entre les régions du littoral et de l’intérieur sont révélateurs d’une grande hétérogénéité en termes de niveaux de revenus, de croissance, de chômage, de répartition entre activités à forte et à faible productivités et de pauvreté. Si les régions du littoral font partie de l’axe de compétitivité et constituent le centre des branches phares de l’industrie tunisienne, les autres régions de l’intérieur disposent de moins de compétences stratégiques et affichent des performances moyennes, voire même faibles. Aucun processus de convergence régionale n’est enclenché. L’objet de la thèse est de quantifier et d’appréhender les impacts macroéconomiques et microéconomiques de sept réformes de politiques économiques susceptibles de réduire les disparités régionales, dans le cadre d’une approche macro-micro. Approche qui conduit inévitablement à privilégier un cadre d’analyse qui se compose de deux modèles reliés: un modèle d’équilibre général dynamique et multirégional et un modèle de micro simulation. L’implémentation de ces deux modèles a permis de réaliser un exercice de projection et un autre de simulation. Le premier exercice a étudié l’évolution future de l’économie tunisienne, en absence de toutes réformes économiques et/ou choc exogène. Les résultats montrent que le clivage littoral-intérieur devrait s’accentuer si des mesures de correction ne sont pas mises en œuvre. Les résultats de simulation suggèrent qu’une politique de libéralisation commerciale bénéficie plus aux régions du littoral. Pour stimuler la croissance des régions de l’intérieur, il est préférable d’entreprendre des politiques de discrimination positive qui visent à augmenter leurs niveaux d’investissements public et surtout privé. Par ailleurs, la réduction de l’écart de performance économique entre le littoral et l’intérieur du pays ne peut se faire rapidement qu’au moyen d’un changement technologique important dans les régions de l’intérieur. Tous les scénarios envisagés dans ce travail rejettent la nécessité d’un arbitrage entre croissance et pauvreté régionales et confirment donc les possibilités d’une croissance pro-pauvre. / Almost two decades after the liberalization of the Tunisian economy, regional disparities have been accentuated severely and are expected to grow further. The existing gap between the coastal regions and those inland is showing high inequality in terms of levels of income, growth, unemployment, productivity and poverty. The industry in the littoral regions remains the most competitive leading the Tunisian industry, while other regions in the interior lag behind with fewer strategic competences and skills and medium or even low performance. Hence, the process of regional convergence has been broken rather than achieved. The purpose of this research is to assess and quantify the macroeconomic and microeconomic impacts of seven economic policies which aiming to reduce regional disparities in Tunisia. For that purpose, we will use a micro-macro based approach with two interconnected models: A multiregional dynamic general-equilibrium model and a micro-simulation model. The implementation of these two models has enabled a projection exercise and simulation one. The first exercise studied the future evolution of the Tunisian economy in its national and regional dimensions without any economic and / or exogenous shock reforms. The results show that the littoral-internal cleavage is expected to increase if corrective measures will not be implemented. Simulation results show that trade liberalization policy benefits more to coastal regions. However, to stimulate growth performance on behalf of inland regions, positive discrimination action policies, as public and especially private investment increase, will be necessary. Moreover, reducing the economic gap performance between the coast and the interior can be done quickly through a major technological change for regions in the interior. All scenarios in this study reject the possibility of trade-off between growth and regional poverty and thus confirm the potential for pro-poor growth.

Large-eddy simulation (LES) and unsteady Reynolds-averaged Navier-Stokes (URANS) calculations have been performed to investigate the effects of different mathematical models for scalar variance and its dissipation rate as applied to both a non-reacting bluff-body turbulent flow and an extension to a reacting case. In the conserved scalar formalism, the mean value of a thermo-chemical variable is obtained through the PDF-weighted integration of the local description over the conserved scalar, the mixture fraction. The scalar variance, one of the key parameters for the determination of a presumed β-function PDF, is obtained by solving its own transport equation with the unclosed scalar dissipation rate modelled using either an algebraic expression or a transport equation. The proposed approach is first applied to URANS and then extended to LES. Velocity, length and time scales associated with the URANS modelling are determined using the standard two-equation k-ε transport model. In contrast, all three scales required by the LES modelling are based on the Smagorinsky subgrid scale (SGS) algebraic model. The present study proposes a new algebraic and a new transport LES model for the scalar dissipation rate required by the transport equation for scalar variance, with a time scale consistent with the Smagorinsky SGS model.

Large-eddy simulation (LES) and unsteady Reynolds-averaged Navier-Stokes (URANS) calculations have been performed to investigate the effects of different mathematical models for scalar variance and its dissipation rate as applied to both a non-reacting bluff-body turbulent flow and an extension to a reacting case. In the conserved scalar formalism, the mean value of a thermo-chemical variable is obtained through the PDF-weighted integration of the local description over the conserved scalar, the mixture fraction. The scalar variance, one of the key parameters for the determination of a presumed β-function PDF, is obtained by solving its own transport equation with the unclosed scalar dissipation rate modelled using either an algebraic expression or a transport equation. The proposed approach is first applied to URANS and then extended to LES. Velocity, length and time scales associated with the URANS modelling are determined using the standard two-equation k-ε transport model. In contrast, all three scales required by the LES modelling are based on the Smagorinsky subgrid scale (SGS) algebraic model. The present study proposes a new algebraic and a new transport LES model for the scalar dissipation rate required by the transport equation for scalar variance, with a time scale consistent with the Smagorinsky SGS model.