Towards the development of the supply chain of concentrated solar power

This work focuses on the investigation into the planning of renewable energy power plants in Brazil using the Concentrated Solar Power (CSP) technology. The main aim of the paper is to present an analysis of the planning process that can be used as a basis of the development of a method to assess the Brazilian’s local manufacturing and supply chain capabilities in supporting the deployment of the CSP technology. The paper identifies areas in which the concerted efforts should be emphasized. For this, the paper will first discuss the key components of the chosen CSP technology (in this case the parabolic through). The manufacturing processes of these components will subsequently be analyzed and the key enabling technologies will be determined. The demands of electricity will be estimated using the System Advisory Model®, a modelling tool developed by the National Renewable Energy Laboratory (NREL). An assessment method will finally be proposed to identify the potentials of the local Brazilian supply chain, through the readiness evaluation of the key enabling technologies and manufacturing processes

Health benefits and control costs of tightening particulate matter emissions standards for coal power plants - The case of Northeast Brazil.

Exposure to ambient particulate matter (PM) caused an estimated 4.2 million deaths worldwide in 2015. However, PM emission standards for power plants vary widely. To explore if the current levels of these standards are sufficiently stringent in a simple cost-benefit framework, we compared the health benefits (avoided monetized health costs) with the control costs of tightening PM emission standards for coal-fired power plants in Northeast (NE) Brazil, where ambient PM concentrations are below World Health Organization (WHO) guidelines. We considered three Brazilian PM10 (PMx refers to PM with a diameter under x micrometers) emission standards and a stricter U.S. EPA standard for recent power plants. Our integrated methodology simulates hourly electricity grid dispatch from utility-scale power plants, disperses the resulting PM2.5, and estimates selected human health impacts from PM2.5 exposure using the latest integrated exposure-response model. Since the emissions inventories required to model secondary PM are not available in our study area, we modeled only primary PM so our benefit estimates are conservative. We found that tightening existing PM10 emission standards yields health benefits that are over 60 times greater than emissions control costs in all the scenarios we considered. The monetary value of avoided hospital admissions alone is at least four times as large as the corresponding control costs. These results provide strong arguments for considering tightening PM emission standards for coal-fired power plants worldwide, including in regions that meet WHO guidelines and in developing countries

Limitations of thermal power plants to solar and wind development in Brazil

Some three fourths of electricity generation in Brazil come from renewables. Most of it is supplied by hydro, complemented by biomass-fueled thermal power plants and wind, while solar is still irrelevant. However, in the medium and long terms, a strong growth is expected for wind and solar in the country. Solar and wind resources are variable in time, partially unpredictable and cannot be dispatched to meet the load. These characteristics require system flexibility, which is the capacity of the power grid to adapt to different supply and demand patterns. Given that most thermal plants are not designed for a large frequency of operating cycles, renewables penetration may result in higher maintenance and operating costs, increased fuel consumption and reduced lifetime. Furthermore, some units might be called out-off-merit to maintain voltage and frequency levels. This paper presents preliminary results on the ability of thermal units to provide flexibility to the country´s grid, through an analysis for the Northeast region bounded by transmission constraints among 65 nodes (out of 196 nodes along the country). Results show that the power sector in Brazil might not be well equipped to deal with high penetration rates of variable renewable energy sources, with impacts on the capacity factor, and on the efficiency, of thermal power plants in the country. They also reveal that while wind energy increases the need of ramping capabilities, solar has greater impacts on the number of starts and shutdowns of conventional units.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263). The authors would also like to express their gratitude to the Coordination for the Improvement of Higher Education Personnel (CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the essential support given for this work to be carried out

Global fossil fuel reduction pathways under different climate mitigation strategies and ambitions

The mitigation scenarios database of the Intergovernmental Panel on Climate Change's Sixth Assessment Report is an important resource for informing policymaking on energy transitions. However, there is a large variety of models, scenario designs, and resulting outputs. Here we analyse the scenarios consistent with limiting warming to 2 °C or below regarding the speed, trajectory, and feasibility of different fossil fuel reduction pathways. In scenarios limiting warming to 1.5 °C with no or limited overshoot, global coal, oil, and natural gas supply (intended for all uses) decline on average by 95%, 62%, and 42%, respectively, from 2020 to 2050, but the long-term role of gas is highly variable. Higher-gas pathways are enabled by higher carbon capture and storage (CCS) and carbon dioxide removal (CDR), but are likely associated with inadequate model representation of regional CO2 storage capacity and technology adoption, diffusion, and path-dependencies. If CDR is constrained by limits derived from expert consensus, the respective modelled coal, oil, and gas reductions become 99%, 70%, and 84%. Our findings suggest the need to adopt unambiguous near- and long-term reduction benchmarks in coal, oil, and gas production and use alongside other climate mitigation targets

Methodology for hubs placement analysis: an application to Portuguese industrial CO₂ emissions

Carbon capture and Geological storage (CCGS) is recognised as a technology capable of reducing large-scale emissions of carbon dioxide (CO2), which is an important part of the portfolio of alternatives necessary to achieve significant reductions in the global emissions of greenhouse gases (GHG). As of this context where greenhouses gases constrains in Europe would come, and CCGS would be a mitigation option for GHG, it becomes necessary to develop a CO2 transport network to collect and inject it in a proper geological reservoir. Therefore, the following methodology can help to implement a pipeline network in any region in the world by doing a preliminary analysis about the best places to locate a HUB (temporary CO2 reservoir). In this paper, the demonstration of the methodology refers to Portugal’s industrial emission sources in which CCS could be implemented.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013612263)

La escritura expresiva: ¿Un método eficaz para reducir la depresión y facilitar el perdono y el bienestar de los preadolescentes?

Abstract Expressive writing (EW) can be an effective way to alter maladaptive emotional reactions to stressful life events, although little is known about how pre-adolescents may benefit from it. In this quasi-experimental study, we compared measures of depression, anger, forgiveness, positive and negative affect in pre-adolescents before and after EW in both an experimental group undergoing the EW paradigm and a control group (N=138). No significant effects between control and experimental groups were found for the considered variables, except for positive and negative affect. We suggest potential reasons accounting for these results. Given that the theorised mechanisms involved in the EW paradigm include executive functioning abilities, it is possible that preadolescents may not be able to benefit from it, due to not fully developed executive functioning skills. Our results provide useful information in order to better design future studies and prevention/intervention programmes to be implemented with preadolescents. Resumen La Escritura Expresiva (EE) puede ser una forma efectiva de alterar reacciones emocionales maladaptativas a eventos estresantes de la vida, aunque se sabe poco sobre cómo los pre-adolescentes pueden beneficiarse de ella. En este estudio cuasi-experimental, comparamos medidas de depresión, ira, perdón, afecto positivo y negativo en pre-adolescentes antes y después de EE en un grupo experimental sometido al paradigma de EE y en un grupo de control (N=138). No se encontraron efectos significativos entre los grupos control y experimental para las variables consideradas, excepto para los afectos positivos y negativos. Sugerimos posibles razones para explicar estos resultados. Dado que los mecanismos teóricos implicados en el paradigma de la EE incluyen las capacidades de funcionamiento ejecutivo, es posible que los preadolescentes no puedan beneficiarse de ella, debido a las habilidades de funcionamiento ejecutivo no totalmente desarrolladas. Nuestros resultados proporcionan información útil para un mejor diseño de futuros estudios y programas de prevención / intervención a implementar con preadolescentes

Understanding cost escalation in nuclear reactor construction projects

This work seeks to evaluate overnight construction costs (OCC) and lead time escalation of nuclear reactors from 1955 to 2016. To this end, a comprehensive database of commercial Light Water Reactors (LWR) was developed and a statistical analysis was conducted. Findings reveal that there is significant delay in lead time, especially for the last generation reactors constructed from 2010’s. This results in the escalation of capital costs rather than a decline. Average OCC of newer reactors are 60% higher than the ones implemented in the earlier stages of the nuclear era. This suggests a negative learning curve effect for both OCC and lead time, which threats the market and financial sustainability of current and future nuclear energy projects. Although this is a general trend, this negative effect is country specific and, thus, induced by national policies and regulatory frameworks. Therefore, the role of nuclear technology to cope with the decarbonisation of the power sector must be better evaluated, taking into account the real cost impacts of nuclear technology implementation.This work was also funded by the Brazilian research funding agency CNPq.This work was funded by the Brazilian research funding agency CNPq and the Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under the project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263)

Low-carbon scenarios for the Brazilian power system

The Brazilian power generation sector faces a paradigm change driven, on one hand, by a shift from a hydropower dominated mix and, on the other, by international goals for reducing greenhouse gases emissions. The objective of this work was to evaluate five scenarios for the Brazilian power system until 2050 using a multi-criteria decision analysis tool. These scenarios include a baseline trend and low carbon policy scenarios based on carbon taxes and carbon emission limits. To support the applied methodology, a questionnaire was elaborated to integrate the perceptions of experts on the scenario evaluation process. Taking into account the results from multi-criteria analysis, scenario preference followed the order of increasing share of renewables in the power system. The preferable option for the future Brazilian power system is a scenario where wind and biomass have a major contribution. The robustness of the multi-criteria tool applied in this study was tested by a sensitivity analysis. This analysis demonstrated that, regardless the respondents’ preferences and backgrounds, scenarios with higher shares of fossil fuel sources are the least preferable option, while scenarios with major contributions from wind and biomass are the preferable option to supply electricity in Brazil through 2050.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263)

Efeito da adição de Nb, Mo, Cr e Ti na microestrutura do WC-6Co

Hard metals are a group of materials known as sintered composites involving hard phases (carbides) with a metallic phase, being widely used in applications where you want high hardness and wear resistance combined with high toughness. This article presents the results of adding 1% by weight of the elements Nb, Ti, Cr and Mo on the microstructure of the hard metal from a commercial composite of WC-6Co. In this composite was added 1.5% (by weight) of zinc stearate as lubricant and sintered at a temperature of 1450ºC in an atmosphere of argon. Aiming to analyze the product efficiency was held on micro structural characterization through the testing of green density, shrinkage, sintered density, microstructure and microhardness. Key words: hard metal, carbide, balancing mass, powder metallurgy, sintering.Os metais duros constituem um grupo de materiais conhecidos como compósitos sinterizados que associam fases duras (carbetos), com uma fase metálica sendo amplamente utilizados em aplicações onde se deseja elevada dureza e resistência ao desgaste, aliada à alta tenacidade. Neste artigo apresentam-se os resultados da adição de 1% em peso dos elementos Nb, Ti, Cr e Mo na microestrutura do metal duro a partir de um compósito comercial de WC-6Co. A esse compósito foi adicionado 1,5% (em peso) de estearato de zinco como lubrificante e sinterizados na temperatura de 1450ºC numa atmosfera de Argônio. Com o objetivo de analisar-se a eficiência do produto, realizou-se a caracterização micro estrutural através dos ensaios de densidade à verde, contração volumétrica, densidade da sinterização, microestrutura e microdureza. Palavras-chave: metal duro, carbetos, balanceamento de massa, metalurgia do pó, sinterização