This thesis undertakes three separate lifecycle analyses to determine the emissions and fossil energy demand required to process algae biomass into renewable fuel and animal feed. A complete well-to-wheel fuel-cycle analysis is conducted for the production of biodiesel and jet biofuel from algae biomass. The environmental impacts of algae-based fuels for the road transportation and aviation industry are benchmarked against analogue conventional fossil fuels. This thesis demonstrates that algae biofuel production can only realize its inherent environmental advantage of reduced GHG emissions, once every step of the production chain is fully optimized and decarbonized. This includes smart co-product utilization, offsetting fertilizers through wastewater recycling, reusing exhaust gases as additional CO2 source and using decarbonized electricity, heat and indirect energy. The definition of a Catalyst Sensitivity Index (CSI) demonstrates how catalytic efficiency increases can impact the fossil energy consumption and the greenhouse gas emissions balance of catalyst-dependent processes. The CSI will allow the industry to highlight 'best practice catalysts' and draw conclusions for what efficiency gains one could anticipate with higher performance catalysts. For countries where a decarbonized electricity and heat grid is not available to guarantee low-carbon algae fuel production and the looming resource scarcity around marine feed production has become more pressing, the alternative use of algae for aquafeed production is recommended. This thesis analyses major routes towards the future cost-competitive production of microbial biomass as sustainable fish meal and oil source to meet a global demand for depleting fish feed supplies. A comprehensive economic cost analysis and lifecycle assessment demonstrates the feasibility of replacing global fish meal and fish oil supplies with low-carbon and affordable algae feed by the year 2030. This research reveals how algae feed production has the potential to transform a pressing resource tipping point into a turning point.

Large-scale deployment of low-carbon energy technologies is important for counteracting anthropogenic climate change and achieving universal energy access. This thesis explores potential growth rates of technologies necessary to reach a more sustainable global energy system, the material and energy flows required to commission these technologies, and potential future availability of the required resources. These issues are investigated in five papers. Potential future growth rates of wind energy and solar photovoltaics, and the associated material requirements are explored, taking the expected service life of these technologies into account. Methodology for assessing net energy return and natural resource use for wind energy systems are analyzed. Potential future availability of lithium and phosphate rock are also investigated. Estimates of energy and materials required for technologies such as wind energy and photovoltaics vary, and depend on the assumptions made and methods used. Still, it is clear that commissioning of low-carbon technologies on the scale required to reach and sustain a low-carbon energy system in coming decades requires significant quantities of both bulk materials and scarcer resources. For some technologies, such as thin film solar cells and electric vehicles with lithium-ion batteries, availability of materials could become an issue for potential growth rates. Future phosphate rock production could become highly dependent on few countries, and potential political, social and environmental aspects of this should be investigated in more detail. Material and energy flows should be considered when analyzing growth rates of low-carbon technologies. Their estimated service life can indicate sustainable growth rates of technologies, as well as when materials are available for end-of-life recycling. Resource constrained growth curve models can be used to explore future production of natural resources. A higher disaggregation of these models can enable more detailed analysis of potential constraints. This thesis contributes to the discussion on how to create a more sustainable global energy system, but the methods to assess current and future energy and material flows, and availability of natural resources, should be further developed in the future.

O Acordo de Paris preconiza que cada país descreva e comunique suas ações climáticas pós-2020. Neste contexto, as Curvas de Custo Marginal de Abatimento (MACC) podem ser úteis aos países e aos tomadores de decisão, pois mostram de forma clara o custo (em unidades monetárias por massa de CO2e) para a implementação de tecnologias de mitigação de emissões de gases do efeito estufa (GEE) e o seu potencial de redução de emissões associado (em massa de CO2e). As MACC podem ser utilizadas para qualquer unidade política, como: país, cidade ou estado. Podem, também, ser aplicadas a diversas áreas, tais como: transporte, construção, poluição do ar, agricultura ou indústria. Diante desta diversidade de estudos e aplicações, o objetivo do presente trabalho foi desenvolver uma metodologia de adaptação de MACC, de estudos publicados na literatura, para qualquer unidade política ou ano de interesse. Isto permitirá a \"reutilização\" destas MACC, porém sem a necessidade da realização de novos estudos. O desenvolvimento da metodologia de adaptação prescindiu de uma meta-análise e harmonização de dados da literatura. A metodologia desenvolvida foi aplica ao Brasil, considerando os subsetores industriais de cimento e de siderurgia. Ela foi, também, implementada no software Access® (e denominada re-MACC) para que todo o processo de adaptação das MACC pudesse ser realizado automaticamente. Analisando um total de 178 tecnologias de baixo carbono para os subsetores de cimento e de siderurgia, o resultado mostrou que seria possível reduzir, em 2014, aproximadamente 52,4% das emissões de CO2e, gerando uma economia monetária de 1.835 US$/tCO2e, caso o Brasil as adotasse. A metodologia foi capaz de harmonizar dados para qualquer unidade política ou ano de interesse, todavia refinamentos são necessários para torná-la ainda mais acurada / The Paris Agreement calls on each country to describe and report on its climate actions post-2020. In this context, the Marginal Abatement Cost Curves (MACC) can be useful to countries and decision makers as they clearly show the cost (in monetary units per mass of CO2e) for the implementation of greenhouse gas (GHG) emission mitigation technologies and their associated emission reduction potential (in mass of CO2e). They can be used for any jurisdiction, such as country, city or state. They can also be applied to several areas, such as: transportation, buildings, air pollution, agriculture or manufacturing. In view of this diversity of studies and applications, the objective of the present work was to develop a methodology for adapting MACC, from studies published in the literature, to any jurisdiction or year of interest. This work allows for \"re-using\" these MACC, but without the need for new studies. The development of the methodology is based on a meta-analysis and harmonization of literature data. The methodology was applied to Brazil, considering the industrial cement and steel subsectors. It was implemented in the Access® software (and called re-MACC) so the MACC adaptation process could be performed automatically. Analyzing a total of 178 low-carbon technologies for the Brazilian industrial subsectors of cement and steel, the result showed that it would be possible to reduce by approximately 52.4% of CO2e emissions by 2014, generating monetary savings of 1,835 US$/tCO2e. The methodology proved to be capable in harmonizing the data, however further refinements are needed to make it even more accurate

A partir de uma perspectiva crítica, esta pesquisa analisa a maneira pela qual os programas políticos para mudanças climáticas e atividades compensatórias de gases de efeito estufa tornam-se realidade no território brasileiro. A pesquisa faz uma análise crítica da constituição de uma economia de baixo carbono na Amazônia, mais detidamente sobre seus desdobramentos em questões agrárias nos estados da Amazônia Legal, além de apresentar dois casos ilustrativos sobre projetos de carbono envolvendo florestas no estado do Pará. Busca-se, assim, discutir as coexistências e antagonismos nas relações que se estabelecem entre as atividades regulares de comunidades rurais seus usos econômicos e formas de convivência com a floresta amazônica (especificamente madeira e agricultura) , e a introdução dos atuais projetos de desmatamento evitado. Diante da complexidade na qual se apresenta o atual contexto das mudanças climáticas, a pesquisa se vale de uma análise que se apropria de conceitos fundamentais para geografia contemporânea, como acumulação por espoliação, desenvolvimento geográfico desigual e produção da natureza. Com isso, apresenta-se, ao longo da tese, as questões centrais a respeito de como a floresta amazônica passa a ter novos valores de uso e troca no contexto das mudanças climáticas e como sua ressignificação passa a representar novas estratégias de acumulação de capital. / From a critical perspective, this research examines the ways in which political programs on climate change and compensatory activities of greenhouse gases become reality in Brazil. The research analyzes the establishment of a low carbon economy in the Amazon, more specifically on its consequences on land issues in the Amazonian states, and present two illustrative cases of carbon projects involving forests in the state of Pará. It discusses about the coexistences and antagonisms in relations established between the regular activities of rural communities - their economic uses and ways of living together with the Amazon rainforest (specifically wood and agriculture) - and the introduction of the current projects \"deforestation avoided\". On the complexity that presents the current context of climate change, the research relies on an analysis from fundamental concepts for contemporary geography, as \"accumulation by dispossession\", \"uneven geographical development\" and \"production of nature\". Thus, it presents, along the thesis, the central question about how the Amazon forest is replaced by new use-value and exchange in the context of climate change and how their resignification comes to represent new strategies of accumulation of capital.

O objetivo desta pesquisa é entender como se dá a relação entre fatores humanos e práticas de gestão de baixo carbono sob a perspectiva da Visão Baseada em Recursos (VBR) no setor de biodiversidade, por meio da realização de survey e estudo de múltiplos casos. Assim, a seguinte problemática de pesquisa é elaborada: qual é a relação existente entre fatores humanos críticos de sucesso e a adoção de práticas de gestão de baixo carbono (sendo a Visão Baseada em Recursos o pano de fundo na análise)? A análise quantitativa (por meio da Modelagem de Equações Estruturais) evidenciou que as três ramificações da hipótese principal foram aceitas - sendo que a primeira com maior coeficiente que a segunda; e a segunda com maior coeficiente que a terceira. Dessa forma, observou-se que os fatores humanos influenciaram mais as práticas de gestão de baixo carbono de produto; em segundo lugar, as práticas de processo; e por fim as práticas de logística. A pesquisa qualitativa baseou-se na estratégia de múltiplos casos, com foco principal na relação entre os fatores humanos críticos de sucesso e a adoção (evolução) das práticas organizacionais de gestão de baixo carbono. Os resultados evidenciaram que as empresas se encontram em diferentes estágios de maturidade em relação às práticas organizacionais de gestão de baixo carbono, variando desde o estágio mais alto até o mais baixo. Verificou-se que a intensidade (de presença) dos fatores humanos críticos de sucesso foi maior à medida que a organização possuísse maior adoção de práticas de gestão de baixo carbono / The aim of this research is to understand the relationship between human factors and low carbon management practices from the perspective of the Resource Based View (VBR) in the biodiversity sector, through a survey and multiple cases study. Thus, the following research question is proposed: what is the relationship between human critical success factors and the adoption of low carbon management practices (Resource Based View as the background to the analysis)? The quantitative analysis (through Structural Equations Modeling) showed that all the three ramifications of the main hypothesis were accepted - the first one having a higher coefficient than the second one; and the second one with a higher coefficient than the third one. Thus, it was observed that the human factors influenced more the low carbon management practices of product; secondly, the process practices; and finally the logistics practices. The qualitative research was based on multiple case approach (6 cases), with a main focus on the relationship between critical human success factors and the adoption (evolution) of low carbon management organizational practices. The results showed that companies can be placed at different stages of maturity in relation to organizational practices of low carbon management, ranging from the highest to the lowest stage. It was found that the intensity of critical human success factors was greater as the organization had more adoption of low carbon management practices

O objetivo desta pesquisa é entender como se dá a relação entre fatores humanos e práticas de gestão de baixo carbono sob a perspectiva da Visão Baseada em Recursos (VBR) no setor de biodiversidade, por meio da realização de survey e estudo de múltiplos casos. Assim, a seguinte problemática de pesquisa é elaborada: qual é a relação existente entre fatores humanos críticos de sucesso e a adoção de práticas de gestão de baixo carbono (sendo a Visão Baseada em Recursos o pano de fundo na análise)? A análise quantitativa (por meio da Modelagem de Equações Estruturais) evidenciou que as três ramificações da hipótese principal foram aceitas - sendo que a primeira com maior coeficiente que a segunda; e a segunda com maior coeficiente que a terceira. Dessa forma, observou-se que os fatores humanos influenciaram mais as práticas de gestão de baixo carbono de produto; em segundo lugar, as práticas de processo; e por fim as práticas de logística. A pesquisa qualitativa baseou-se na estratégia de múltiplos casos, com foco principal na relação entre os fatores humanos críticos de sucesso e a adoção (evolução) das práticas organizacionais de gestão de baixo carbono. Os resultados evidenciaram que as empresas se encontram em diferentes estágios de maturidade em relação às práticas organizacionais de gestão de baixo carbono, variando desde o estágio mais alto até o mais baixo. Verificou-se que a intensidade (de presença) dos fatores humanos críticos de sucesso foi maior à medida que a organização possuísse maior adoção de práticas de gestão de baixo carbono / The aim of this research is to understand the relationship between human factors and low carbon management practices from the perspective of the Resource Based View (VBR) in the biodiversity sector, through a survey and multiple cases study. Thus, the following research question is proposed: what is the relationship between human critical success factors and the adoption of low carbon management practices (Resource Based View as the background to the analysis)? The quantitative analysis (through Structural Equations Modeling) showed that all the three ramifications of the main hypothesis were accepted - the first one having a higher coefficient than the second one; and the second one with a higher coefficient than the third one. Thus, it was observed that the human factors influenced more the low carbon management practices of product; secondly, the process practices; and finally the logistics practices. The qualitative research was based on multiple case approach (6 cases), with a main focus on the relationship between critical human success factors and the adoption (evolution) of low carbon management organizational practices. The results showed that companies can be placed at different stages of maturity in relation to organizational practices of low carbon management, ranging from the highest to the lowest stage. It was found that the intensity of critical human success factors was greater as the organization had more adoption of low carbon management practices

O Acordo de Paris preconiza que cada país descreva e comunique suas ações climáticas pós-2020. Neste contexto, as Curvas de Custo Marginal de Abatimento (MACC) podem ser úteis aos países e aos tomadores de decisão, pois mostram de forma clara o custo (em unidades monetárias por massa de CO2e) para a implementação de tecnologias de mitigação de emissões de gases do efeito estufa (GEE) e o seu potencial de redução de emissões associado (em massa de CO2e). As MACC podem ser utilizadas para qualquer unidade política, como: país, cidade ou estado. Podem, também, ser aplicadas a diversas áreas, tais como: transporte, construção, poluição do ar, agricultura ou indústria. Diante desta diversidade de estudos e aplicações, o objetivo do presente trabalho foi desenvolver uma metodologia de adaptação de MACC, de estudos publicados na literatura, para qualquer unidade política ou ano de interesse. Isto permitirá a \"reutilização\" destas MACC, porém sem a necessidade da realização de novos estudos. O desenvolvimento da metodologia de adaptação prescindiu de uma meta-análise e harmonização de dados da literatura. A metodologia desenvolvida foi aplica ao Brasil, considerando os subsetores industriais de cimento e de siderurgia. Ela foi, também, implementada no software Access® (e denominada re-MACC) para que todo o processo de adaptação das MACC pudesse ser realizado automaticamente. Analisando um total de 178 tecnologias de baixo carbono para os subsetores de cimento e de siderurgia, o resultado mostrou que seria possível reduzir, em 2014, aproximadamente 52,4% das emissões de CO2e, gerando uma economia monetária de 1.835 US$/tCO2e, caso o Brasil as adotasse. A metodologia foi capaz de harmonizar dados para qualquer unidade política ou ano de interesse, todavia refinamentos são necessários para torná-la ainda mais acurada / The Paris Agreement calls on each country to describe and report on its climate actions post-2020. In this context, the Marginal Abatement Cost Curves (MACC) can be useful to countries and decision makers as they clearly show the cost (in monetary units per mass of CO2e) for the implementation of greenhouse gas (GHG) emission mitigation technologies and their associated emission reduction potential (in mass of CO2e). They can be used for any jurisdiction, such as country, city or state. They can also be applied to several areas, such as: transportation, buildings, air pollution, agriculture or manufacturing. In view of this diversity of studies and applications, the objective of the present work was to develop a methodology for adapting MACC, from studies published in the literature, to any jurisdiction or year of interest. This work allows for \"re-using\" these MACC, but without the need for new studies. The development of the methodology is based on a meta-analysis and harmonization of literature data. The methodology was applied to Brazil, considering the industrial cement and steel subsectors. It was implemented in the Access® software (and called re-MACC) so the MACC adaptation process could be performed automatically. Analyzing a total of 178 low-carbon technologies for the Brazilian industrial subsectors of cement and steel, the result showed that it would be possible to reduce by approximately 52.4% of CO2e emissions by 2014, generating monetary savings of 1,835 US$/tCO2e. The methodology proved to be capable in harmonizing the data, however further refinements are needed to make it even more accurate

Since the late 1980s, the energy sector in Great Britain has undergone some core changes in its functionality; beginning with the early 1990s privatisation, followed by an increased green ambition, and commencing a transition towards a low-carbon economy. As the British energy sector prepares itself for another major overhaul, it also puts itself at risk for not being sufficiently prepared for the consequences this transition will have on the existing generating capacity, security of supply, and the national electricity market. Upon meeting existing targets, the government of the United Kingdom risks becoming complacent, putting energy regulation to the backseat and focusing on other regulatory tasks, while introducing cuts for thriving renewable and other low-carbon energy generating technologies. The government has implemented a variety of directives, initiatives, and policies that have sometimes been criticised due to their lack of clarity and potential overlap between energy and climate change directives. The government has introduced policies that aim to provide stable short-term solutions. However, a concrete way of resolving the energy trilemma and some of the long-term objectives and more importantly ways of achieving them are yet to be developed. This work builds on analysing each low-carbon technology individually by assessing its past and current state in the British energy mix. By accounting for the changes and progress the technology underwent in its journey towards becoming a part of the energy capacity in Great Britain, its impact on the future wholesale electricity prices is studied. Research covered in this thesis presents an assessment of the existing and incoming low-carbon technologies in Great Britain and their individual and combined impact on the future of British energy economics by studying their implications for the electricity market. The methodological framework presented here uses a cost-minimisation merit order model to provide useful insights for novel methods of electricity production and conventional thermal energy generation to aid with the aftermath of potential inadequate operational and fiscal flexibility. The thesis covers a variety of scenarios differing in renewable and thermal penetration and examines the impact of interconnection, energy storage, and demand side management on the British wholesale electricity prices. The implications of increasing low-carbon capacity in the British energy mix are examined and compared to similar developments across Europe. The analysis highlights that if the optimistic scenarios in terms of green energy installation are followed, there is sufficient energy supply, which results in renewable resources helping to keep the wholesale price of electricity down. However, if the desired capacity targets are not met, the lack of available supply could result in wholesale prices going up, especially in the case of a natural gas price increase. Although initially costly, the modernisation of the British grid leads to a long-term decrease in wholesale electricity prices and provides a greater degree of security of supply and flexibility for all market participants.

O processo de lingotamento contínuo de produtos planos de aço tem sido alvo de incessantes estudos devido a sua importância na produção de bobinas laminadas a partir de placas, para um grupo muito diversificado de clientes, dentre os quais, destacam-se as indústrias automobilística e de eletrodomésticos (\"linha branca\"), que têm se mostrado muito exigentes. No entanto, por tratar-se de aços desoxidados ao alumínio, é comum a ocorrência de formação de um depósito de óxido de alumínio (alumina), no interior do tubo submerso do processo de lingotamento contínuo, o que diminui seu diâmetro interno, levando à restrição de passagem do aço líquido pelo seu interior, provocando a perda de produtividade devido à necessidade de se reduzir a velocidade de lingotamento e até mesmo a contaminação do aço com inclusões de alumina, principalmente naqueles seqüenciais com um elevado tempo de lingotamento, próximo de dez horas. Para tanto, desenvolveu-se um tubo com um material interno anti-clogging que na literatura é chamado de C-less, para minimizar e/ou evitar a deposição de alumina e com uma linha de escória reforçada com uma camada de zircônia (ZrO2) mais espessa e mais nobre, para resistir ao ataque da escória. O objetivo desta dissertação foi comparar tubos de diferentes fornecedores, avaliando as principais variáveis que têm influência direta na sua performance: perfil de aquecimento, taxa de erosão na linha de escória, índice de obstrução e parâmetros físico-químicos através da correlação dos materiais antes e após uso (post-mortem). Os resultados encontrados mostraram uma melhor performance dos tubos do fornecedor \"M\", que apresentaram menores taxas de desgaste e, conseqüentemente, maior potencial de vida (maior tempo de lingotamento) após análise da linha de escória, que pode ser atribuída a uma melhor distribuição dos grãos de zircônia na matriz (maior homogeneidade), além de apresentarem grãos mais finos e desta forma, reduzindo os espaços \"vazios\" na matriz, propícios ao ataque da escória por meio de um desequilíbrio químico entre esta escória líquida e o refratário. Além disto, seu material anti-clogging e projeto de distribuição do mesmo na peça, propiciaram um melhor resultado em relação à obstrução pela deposição de alumina ao longo do corpo do tubo submerso. / The continuous casting process of steel plane products has been objective of incessant studies due to its importance in the production of laminated coils starting from slabs, for a very diversified group of customers, among all the automobile industries and of appliances (\"home appliances\"), that have been showing very demanding. However, for being low carbon aluminum killed steels, is common the occurrence of aluminum oxide (alumina) deposit formation, inside of submerged nozzle in continuous casting process, what decreases its internal diameter, taking to the restriction of passage of the liquid steel for its interior, provoking the productivity loss due to the need of being reduced the casting speed and even the contamination of the steel with alumina inclusions, mainly in those sequential with a high casting time, close of ten hours. For so much, a submerged nozzle was developed with a internal anti-clogging material that it is called C-less in the literature, to minimize and/or to avoid the alumina building up and with a slag reinforced line with a zirconium layer (ZrO2) thicker and more noble, slag attack resist to. The dissertation objective was compare submerged nozzles from different suppliers, evaluating the main variables that have direct influence in its performance: heating profile, slag line erosion rate, clogging index and physical-chemical parameters through the materials correlation before and after use (post-mortem). The results showed submerged nozzle\'s better performance from supplier \"M\", that presented smaller waste rates and, consequently, last longer live (larger time of casting) after analysis of the slag line, that can be attributed to a better distribution of the zirconium grains in the head office (larger homogeneity), besides they present finer grains and this way, reducing the empty \" spaces \" in the head office, favorable to slag attack by means of a chemical unbalance between this liquid slag and the refractory. Besides, its anti-clogging material and project distribution in the same piece, they propitiated a better result in relation to the clogging for the alumina building up along the body of the submerged nozzle.

Ou study focuses on the effects of phase transformations on crack propagation. We want to understand the changes of fracture toughness during welding. In this work, fracture toughness is expressed by J-integral. There are many experimental methods to obtain the critical toughness JIC but they are impractical for our investigation during phase transformation. That is the reason why we have proposed a method coupling mechanical tests, digital image correlation and finite element simulation. The fracture tests are implemented on pre-cracked single edge notched plate sample which is easy for machining and heat conduct during phase transformation. The tests are conducted at different temperatures until rupture. Digital image correlation gives us the displacement information on every sample. Each test is then simulated by finite element where the fracture toughness is evaluated by the method G-Theta at the crack propagation starting moment found by potential drop method and digital image correlation technical. Two materials have been studied, 15Cr-5Ni martensitic precipitation hardening stainless steel and 16MND5 ferritic low carbon steel. For these two materials, different test temperatures were chosen before, during and after phase transformation for testing and failure characterization of the mechanical behavior. Investigation result shows that metallurgical phase transformation has an influence on fracture toughness and further crack propagation. For 15-5PH, the result of J1C shows that the as received 15-5PH has higher fracture toughness than the one at 200°C. The toughness is also higher than the original material after one cycle heat treatment probably due to some residual austenite. Meanwhile, pure austenite 15-5PH at 200°C has higher fracture toughness than pure martensitic 15-5PH at 200°C. For 16MND5, the result also proves that the phase transformation affects fracture toughness. The as received material has bigger J1C than the situation where it was heated to 600°C. On the other hand, the material at 600°C just before isothermal bainite transformation after the austenitization during cooling process also has higher fracture toughness than the one at 600°C before austenitization. These two conclusions are consistent well with the result of 15-5PH. But the final situation of 16MND5 after one cycle heat treatment has a slightly smaller J1C than the receiving situation. It means that one cycle heat treatment hasn't an significant influence on 16MND5fracture toughness. Conclusions show that one should pay attention to the heating period before austenitization of the substrate material when people do the welding as the higher temperature will bring the lower fracture toughness during this process. While during cooling period, the fracture toughness doesn't change a lot during, before or after the cooling induced phase transformation. Even for 15-5PH, it has a better fracture toughness after the martensite transformation than before.