Este trabalho aborda diversas implicações de ordem tecnológica, ambiental e social relacionados ao uso de carvão vegetal nos pólos guseiros. Através de coleta de dados em publicações técnicas, visitas a centros de tecnologia guseira e entrevistas com especialistas da área, foram levantadas as informações que serviram de base à elaboração deste trabalho. A análise e interpretação dos resultados obtidos mostram que a manutenção da produção de ferro-gusa depende do contínuo fornecimento de carvão vegetal, como termo-redutor de boa capacidade calorífica, preço baixo e fácil acesso. Todavia, nas condições atuais, o suprimento de carvão vegetal à indústria está relacionado à exploração intensiva de florestas nativas e uma correspondente falta de áreas reflorestadas capazes de suprir a demanda de lenha para carvoejamento. Além do carvão vegetal, outros insumos também podem ser usados na redução do minério de ferro: o gás natural (na produção integrada de aço) o carvão de coco de babaçu, o carvão vegetal de espécies nativas da Amazônia e mesmo o carvão mineral. Estes insumos, entretanto, apresentam problemas ainda não totalmente quantificados, como suprimento, tecnologia adequada de uso e custos de exploração. O uso intensivo de carvão vegetal se baseia na existência de uma rede de carvoejadores e fornos, que operam num ritmo de trabalho intenso (às vezes cerca de quinze horas por dia), baixa remuneração por madeira carvoejada (meio dólar por metro cúbico de carvão vegetal) e falta de seguridade social. De modo geral, os produtos de gusa pouco consideram o uso de carvão de florestas plantadas, pois admitem que um carvão de maior custo, constituir-se-ia em ameaça à própria continuação da produção de ferro-gusa. / The aim of this work is to discuss implications technological, environmentally and social limitations of the pig-iron´s production using charcoal. Through technical papers, technical visits to research centers and interview with experts, a data basis was collected to produce this work. The analysis of data showed that: the continuity of pig-iron making depends on continuos supply of charcoal, at low cost, with good heat capacity, and with easy acess. However, under current conditions, the charcoal supply to industry is depending of a intensive exploration of native forest. At the same time, there is a lack of land suitablefor reforestation to provide wood to renewable charcoal making. Nevertheless, there are several resources that can be used to reduce the iron ore: charcoal of babassu coconut, charcoal of native amazonic trees, natural gas (integrated plants) and even coal. Some of them are candidates to replace the charcoal, but further technological, infrastructural and economic developments are still required. The intensive utilization of charcoal by siderurgy is based in a network of kilns and charcoal makers working under extreme conditions (indeed, some work fifteen hours per day), they have no social security and extremely low wages (some receive only half a dollar per cubic metre of charcoal). In general, pig-iron´s makers do not consider the use of charcoal from forested wood, because its higher cost may challenge the viability of pig-iron production.

A vinhaça da cana-de-açúcar constitui-se no principal resíduo líquido gerado pelo setor sucro-alcooleiro e, face aos enormes volumes produzidos , os problemas decorrentes de seu armazenamento e disposição o final passaram a constituir nos últimos tempos num grande desafio a técnicos envolvidos com essa questão. Este estudo tem por objetivo apresentar uma alternativa de aproveitamento desse resíduo, Aquelas tradicionalmente conhecidas no meio alcooleiro, por .intermédio do tratamento e transformação da vinhaça em biogás e sua utilização na geração de eletricidade. Para tanto, adotou-se a tecnologia de digestão anaeróbia de alta eficiência através de digestores de fluxo ascendente para a produção de biogás e, uma vez purificado, o aproveitamento desse gás em motores e turbinas adequadas a esse tipo de combustíve1, conforme a literatura consultada. No sentido de avaliar a viabilidade prática deste trabalho, optou-se pela elaboração de um estudo de caso, no qual foi dimensionada uma destilaria hipotética de \'cerca de 150.000 litros de álcool/dia, gerando um volume de cerca de 1.800.000 litros de vinhaça/dia. Por meio desta simulação, foram analisados os aspéctos técnicos e econômicos envolvidos, possibilitando assim, uma apreciação crítica e realista do estudo proposto. / The vinasse of sugar-cane represents the main liquid residue produced by the sugar-alcohol sector and, in view of the enormous volumes produced, the problems related to its storage and final disposal came to pose a great challenge to the technical people involved in this matter these last few years. This study aims to present an alternative for the exploitation of this residue, to these traditionally employed in the alcohol production industry, based on the treatment and transformation of vinasse to biogas, and its subsequent utilization in eletric generation. In this context the technology of high efficiency anaerobic digestion using up-flow anaerobic digestors for biogas production was adapted. Once purified, the biogas produced can be utilized in engines and turbines specially adapted for this fuel, as evinced in the literature consulted. With a view to evaluate the pratical feasibility of this work, the elaboration of a case study was selected, in which a hypothetical distillery with a capacity of about 150.000 litres of alcohol/day, would generate a volume of about 1.800.000 litres of vinasse/day. By means of this simulation, the technical and economic aspects involved were analyzed, thus making possible a critical and realistic appreciation of the study proposed.

<p> Anaerobic digestion can use cow manure and waste paper to produce energy in the form of flammable biogas. The grouping of these substrates is not well studied in comparison to other waste feedstocks. Finding ideal operating parameters and models to predict biogas production are vital for future studies and applications. Office paper and cow manure were combined in different ratios at 38.5&deg;C. Four models (Time-Lag, No-Lag, Modified Gompertz, Modified Logistic) were fit to the experimental data to determine which model best predicted biogas production. The digester containing a paper to manure ratio of 2:1 generated the most biogas, but the 5:1 reactor had the greatest biogas production potential based on the model predictions. Models were not consistent in the accuracy of their fit to the data for each treatment. The use of various models when examining anaerobic digestion is important to ensure the best models are selected for future studies.</p><p>

<p> Community solar is a renewable energy practice that&rsquo;s been adopted by multiple U.S. states and is being considered by many more, including the state of Oregon. A recent senate bill in Oregon, called the &ldquo;Clean Electricity and Coal Transition Plan&rdquo;, includes a provision that directs the Oregon Public Utility Commission to establish a community solar program for investor-owned utilities by late 2017. Thus, energy consumers in Portland will be offered participation in community solar projects in the near future. Community solar is a mechanism that allows ratepayers to experience both the costs and benefits of solar energy while also helping to offset the proportion of fossil-fuel generated electricity in utility grids, thus aiding climate change mitigation. </p><p> For community solar to achieve market success in the residential sector of Portland, ratepayers of investor-owned utilities must socially accept this energy practice. The aim of this study was to forecast the potential social acceptance of community solar among Portland residents by measuring willingness to participate in these projects. Additionally, consumer characteristics, attitudes, awareness, and knowledge were captured to assess the influence of these factors on intent to enroll in community solar. The theory of planned behavior, as well as the social acceptance, diffusion of innovation, and dual-interest theories were frameworks used to inform the analysis of community solar adoption. These research objectives were addressed through a mixed-mode survey of Portland residents, using a stratified random sample of Portland neighborhoods to acquire a gradient of demographics. 330 questionnaires were completed, yielding a 34.2% response rate. </p><p> Descriptive statistics, binomial logistic regression models, and mean willingness to pay were the analyses conducted to measure the influence of project factors and demographic characteristics on likelihood of community solar participation. Roughly 60% of respondents exhibited interest in community solar enrollment. The logistic regression model revealed the percent change in utility bill (essentially the rate of return on the community solar investment) as a dramatically influential variable predicting willingness to participate. Community solar project scenarios also had a strong influence on willingness to participate: larger, cheaper, and distant projects were preferred over small and expensive local projects. Results indicate that community solar project features that accentuate affordability are most important to energy consumers. Additionally, demographic characteristics that were strongly correlated with willingness to enroll were politically liberal ideologies, higher incomes, current enrollment in green utility programs, and membership in an environmental organization. Thus, the market acceptance of community solar in Portland will potentially be broadened by emphasizing affordability over other features, such as community and locality. </p><p> Additionally, I explored attitudinal influences on interest in community solar by conducting exploratory factor analysis on attitudes towards energy, climate change, and solar barriers and subsequently conducting binomial logistic regression models. Results found that perceiving renewable energy as environmentally beneficial was positively correlated with intent to enroll in community solar, which supported the notion that environmental attitudes will lead to environmental behaviors. The logistic regression model also revealed a negative correlation between community solar interest and negative attitudes towards renewable energy. Perceptions of solar barriers were mild, indicating that lack of an enabling mechanism may be the reason solar continues to be underutilized in this region.</p><p>

Abstract not available.

This dissertation examines the employment impacts of investments in renewable energy and energy efficiency in the U.S. A broad expansion of the use of renewable energy in place of carbon-based energy, in addition to investments in energy efficiency, comprise a prominent strategy to slow or reverse the effects of anthropogenic climate change. This study first explores the literature on the employment impacts of these investments. This literature to date consists mainly of input-output (I-O) studies or case studies of renewable energy and energy efficiency (REEE). Researchers are constrained, however, by their ability to use the I-O model to study REEE, since currently industrial codes do not recognize this industry as such. I develop and present two methods to use the I-O framework to overcome this constraint: the synthetic and integrated approaches. In the former, I proxy the REEE industry by creating a vector of final demand based on the industrial spending patterns of REEE firms as found in the secondary literature. In the integrated approach, I collect primary data through a nationwide survey of REEE firms and integrate these data into the existing I-O tables to explicitly identify the REEE industry and estimate the employment impacts resulting from both upstream and downstream linkages with other industries. The size of the REEE employment multiplier is sensitive to the choice of method, and is higher using the synthetic approach than using the integrated approach. I find that using both methods, the employment level per $1 million demand is approximately three times greater for the REEE industry than for fossil fuel (FF) industries. This implies that a shift to clean energy will result in positive net employment impacts. The positive effects stem mainly from the higher labor intensity of REEE in relation to FF, as well as from higher domestic content and lower average wages. The findings suggest that as we transition away from a carbon-based energy system to more sustainable and low-carbon energy sources, approximately three jobs will be created in clean energy sectors for each job lost in the fossil fuel sector.

Most energy sources are derived from the sun, directly or indirectly. Stopping the increase of heat-trapping carbon dioxide in the atmosphere will likely require more reliance on current rather than ancient terrestrial solar input. Yet which forms of renewable energy are most appropriately used is a significant question for the twenty-first century. This dissertation concerns the potential supply of biomass energy crops as a renewable energy source in Massachusetts. Biomass represents a low-efficiency solar collector, and supplying society with an important portion of its energy from biomass would require a great deal of land. The cellulosic biomass crop evaluated in this research is switchgrass, among the most studied of possible biomass crops. The study looks at biomass energy crop potential from three perspectives. First, a biomass crop supply function is developed for switchgrass by (1) using a GIS model to estimate land availability by current land use and soil type; (2) using a crop-growth simulation model to estimate potential switchgrass yields; (3) estimating marginal production cost by land parcel; and (4) calculating a supply function from marginal production costs. Total technical potential is estimated to be about 1.3 million dry metric tons of switchgrass per year, though financial constraints would likely limit production to some portion of the estimated 125,000 metric tons per year that could be produced on existing grasslands. Next, the study examines circumstances under which landowners might opt to make land available for biomass crop production. The social challenge of minimizing biomass energy cost is described. Potential biomass crop landowner decisions are characterized in a theoretical utility maximization model, with results suggesting that non-price attributes of crop production are likely important to landowners. Finally, an empirical study using a landowner survey assesses interest in growing biomass crops, and uses contingent valuation (CV) to estimate landowner willingness to accept (WTA) land rent for biomass crops. The median estimate is $321/ha/yr, with a much-higher mean estimate of $658/ha/yr (based on a parametric estimator). While the realistic potential for biomass crops is some fraction of technically feasible potential, there are other potentially important roles for biomass crops in Massachusetts, for example in preserving unused farmland that would otherwise revert to forest.

Offshore floating wind turbines represent the future of wind energy. However, significant challenges must be overcome before these systems can be widely used. Because of the dynamics of offshore floating wind turbines—surge, sway, heave, roll, pitch, and yaw—and the resulting interactions between the rotor and generated wake, the aerodynamic analysis methods and design codes that have found wide use throughout the wind energy industry may be inadequate. Application of these techniques to offshore floating wind turbine aerodynamics may result in off-optimal designs, effectively handicapping these next-generation systems, thereby minimizing their full potential. This dissertation will demonstrate that the aerodynamics of offshore floating wind turbines are sufficiently different from conventional offshore and onshore wind turbines, warranting the use of higher fidelity analysis approaches. It will outline the development and validation of a free vortex wake code, the Wake Induced Dynamics Simulator, or WInDS, which uses a more physically realistic Lagrangian approach to modeling complex rotor-wake interactions. Finally, results from WInDS simulations of various offshore floating wind turbines under different load conditions will be presented. The simulation results indicate that offshore floating wind turbine aerodynamics are more complex than conventional offshore or onshore wind turbines and require higher fidelity analysis approaches to model adequately. Additionally, platform pitching modes appear to drive the most aerodynamically-significant motions, followed by yawing modes. Momentum balance approaches are shown to be unable to accurately model these dynamic systems, and the associated dynamic inflow methods respond to velocity changes at the rotor incorrectly. Future offshore floating wind turbine designs should strive to either minimize platform motions or be complementarily optimized, via higher fidelity aerodynamic analysis techniques, to account for them. It is believed that this dissertation is the first in-depth study of offshore floating wind turbine aerodynamics and the applicability of various analysis methods.^

No description available.

No description available.