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The worldwide scarcity of fossil fuels regarding primary energy demand together with growing environmental concerns have raised new challenges to the world economy, and led to changes in the energy paradigm. Industry, services, researchers, and the Academy are challenged to envisage new solutions through setting up new conversion processes, designing new power systems, and investigating and developing new energy sources and vectors. A broad and up-to-date views on flow systems, energy vectors, together with fuel cells, biomass, and energy recovery issues are covered in this collection. The Guest Editors are grateful to the authors who contributed to this special issue and to all colleagues who participated in the review process.

This article reports the results of a research about the sustai-nability of extractive farmers in the Atlantic slopes of Rio Grande do Sul. The extractive economy at issue is related to a species usually known as leather fern (Rumohra adiantiformis (G.Forest.) Ching). It is estimated that 3,000 families in the region perform this non-regulated activity, whi-ch is their only source of income. The sustainability degree of farmers was calculated from information related to environmental, social and eco-nomic dimensions, and to productivity, stability, equity, resilience, and autonomy criteria. The analysis focused on the comparison among the In-dexes Related to Dimension (IRD), Criteria (IRC) and Sustainability (IRS) of each kind of production system. The results pointed to the existence of four kinds of production systems, and three of them were included in this research. The sustainability indexes showed that the production system type 3 was the most sustainable, followed by type 2 and, fi nally, type 1.

Um nearly zero-energy building (nzeb) é um edifício que produz tanta ou mais energia quanto a que consome num ano típico. As medidas de eficiência assumem um papel de tal forma preponderante na redução das necessidades de consumo que, através da captação de energias renováveis, se torna possível alcançar um balanço de energia zero. Actualmente, a abordagem mais comum é usar a rede pública como fonte e dissipador dessa energia eléctrica. O conceito tem-se expandido de forma notória, dentro ou fora do território nacional, sendo hoje possível aprendermos os conceitos inerentes aos edifícios de energia zero a partir de importantes projectos, como é exemplo disso o edifício Solar XXI em Lisboa. Este documento procura abordar o tema de forma prática e acessível, do ponto de vista das preocupações da arquitectura. Para isso, contribui um caso de estudo que pretende compor uma lógica integradora de várias estratégias determinantes no comportamento térmico do edifício, com intenções de arquitetura contemporânea que se querem fiéis aos seus princípios. A nearly zero-energy building (nzeb) is a sort of building that produces as much or more energy than it consumes in an average year. The efficiency measures play an important role to reduce energy consumption such that the balance of energy needs can be supplied with renewable technologies in order to reach a zero energy result. Today’s approach is usually to use the public grid as a source and a way to dissipate this electric energy. This concept has been spreading in a notorious way in and outside our national territory. With this intention, it is possible today to learn the underlying concepts of the energy zero buildings through several projects, such as the Solar XXI building in Lisbon. This Document approaches this subject in a practical and accessible way, from the point of view of architecture concerns. Additionally it contributes with a case study that develops a set of several strategies that are determinant in the building’s thermal behaviour alongside with contemporary architecture intentions that are supposed to follow their own principles.

This paper means to present the Green GDP (Gross Domestic Product) as a measure of sustainability of one sugarcane mill located in the Central region of Paraná, analyzing its evolution from 2007 to 2011. This paper used the fundamental equation of the Green GDP adapting it to its measurement in the sugarcane industry, enabling the use of Green GDP as a sustainability indicator of the activity of the mill under study. Depletion of water resource and environmental degradation of the mill under study showed rising trend and consequently the Green GDP was lower than the conventional GDP. It reflects the loss of sustainability of the activity of this mill.

This study aimed to identify potential sources of organic matter in sediment, using stable isotopes of carbon (delta13C) and nitrogen (delta15N). Sediment samples were gathered from the margin and in center of three subsystems: Ivinheima, Paraná and Baia, in August/2001. The samples were fractionated granulometrically and separated by size (< 200 µm; 70-200 µm; > 70 µm), prepared and sent to CENA / USP, for identifying the isotopes proportions. Significant differences were detected in the isotopic ratios of the sediment only between sampling stations. The Baía channel presented the lowest delta13C values, while the highest ones were recorded in Paraná river. At this last, delta15N values were negative (-14.41‰). We did not verify significant difference in isotopic composition between the particle sizes of sediment, and between the sampling points. The main sources of carbon for the sediment were C3 macrophytes, periphyton and particulate organic carbon (POC).

Este trabalho tem como objetivo analisar a relação de path dependence no sistema econômico e institucional do álcool combustível no Brasil. O etanol, após fases de crescimento e desafios, tornou-se parte da matriz energética brasileira. Esta trajetória reflete a persistência de uma rota (caminho) traçada sob influência de organizações (usinas e destilarias, setor de máquinas e equipamentos, indústria automobilística, Estado, organizações corporativistas, P&D) e de agentes econômicos (consumidores) voltados, direta ou indiretamente, para a manutenção dessa rota escolhida. Este arranjo de “interesses” deu sustentação ao etanol brasileiro, mesmo em momentos em que a competitividade deste combustível era questionada como opção energética mais adequada para a substituição de gasolina/ diesel. Mesmo após a retomada do setor nos anos 2000, em que a tecnologia flex e as crescentes preocupações acerca das mudanças climáticas impulsionaram o setor no Brasil e no mundo, a escolha do etanol como substituto dos derivados do petróleo ainda se mostra ameaçada por novas tecnologias renováveis e mesmo pela descoberta de novas reservas de petróleo. Fica claro que, caso se deseje manter a liderança no mercado nacional de combustíveis e expandir o mercado internacional para estes produtos, a coalizão em torno do álcool combustível ainda precisará enfrentar diversas questões técnicas e institucionais......This study aims to analyze the relationship of path dependence in the economic and institutional system of ethanol in Brazil. Ethanol, after stages of growth and challenges, has become part of the Brazilian energy matrix. This trajectory reflects the persistence of a path shaped under the influence of organizations (mills and distilleries, machinery and equipment sectors, automotive industry, the government, corporatist organizations, R&D) and economic agents (consumers) interested, directly or indirectly, in the maintenance of the chosen route. This “interest arrangements” supported the Brazilian ethanol, even when this fuel competitiveness was questioned as the most appropriate energy option to substitute gasoline/diesel. Even after the recovery of this sector in the 2000s, when the flex-fuel technology and the GHG (Greenhouse Gases) emissions increased the ethanol demand in Brazil and abroad, the choice of ethanol as the main substitute of fossil fuels is still jeopardized by other renewable fuels and even by the discovery of new oil reserves in Brazil. In order to succeed, the collision supporting the expansion of ethanol in the international market will have to handle a myriad of technological and institutional barriers in Brazil and worldwide.

Currently there is a growing concern about climate change resulting from increased CO2 emissions, leading to an increasing demand of buildings that are more sustainable and energy efficient. The AEC industry have been acquiring more demanding standards of sustainability and energy efficiency, requiring analysis processes to be more complex and integrated with each other. Therefore, it has become vital to implement BIM, enabling greater efficiency in the collaborative process between actors. Thus, the use of BIM can contribute to sustainability through forecasting energy consumption and their usage costs with credibility, reliability and consistency of results. The study of the benefits and barriers to the introduction of BIM in energy analysis of buildings and the analysis of the interoperability between BIM tools and specialized software for energy analysis becomes relevant, as well as the study of workflows that provide good efficiency, which will boost its correct implementation in the AEC industry Currently there is a growing concern about climate change resulting from increased CO2 emissions, leading to an increasing demand of buildings that are more sustainable and energy efficient. The AEC industry have been acquiring more demanding standards of sustainability and energy efficiency, requiring analysis processes to be more complex and integrated with each other. Therefore, it has become vital to implement BIM, enabling greater efficiency in the collaborative process between actors. Thus, the use of BIM can contribute to sustainability through forecasting energy consumption and their usage costs with credibility, reliability and consistency of results. The study of the benefits and barriers to the introduction of BIM in energy analysis of buildings and the analysis of the interoperability between BIM tools and specialized software for energy analysis becomes relevant, as well as the study of workflows that provide good efficiency, which will boost its correct implementation in the AEC industry

Neste trabalho avaliou-se o efeito da data de sementeira nas características de produção e composição em açúcares do sorgo sacarino, em função das quais se estimou o potencial de produção de bioetanol a partir desta cultura. O estudo foi conduzido durante dois anos (2005 e 2006), com a variedade de sorgo sacarino Madhura. A sementeira foi efectuada nas datas de 17 de maio, 31 de maio, 14 de junho e 28 de junho. Na sementeira efectuada a 17 de maio a produção de caules verdes e secos atingiu os valores de 66 e 13,8 t ha-1, respectivamente, as quais foram significativamente superiores às obtidas nas sementeiras de junho. A produção máxima de açúcar naquele mês foi de 4,6 t ha-1, o que corresponde à produção estimada de 2300 L ha-1 de bioetanol. Os resultados alcançados permitem concluir que as datas de sementeira de maio foram as que melhor potenciaram a aptidão do sorgo sacarino como cultura energética, para a produção de bioetanol. Revista de Ciências Agrárias, vol. 36 n.º 3 (2013)

No início do século XXI, notadamente os EUA e UE discutem e promovem o uso de políticas específicas de estímulo à substituição de combustíveis fósseis por fontes renováveis de origem de biomassa. No Brasil desde os anos 70 a produção do etanol representa uma alternativa ecológica geradora de emprego e renda. A produção de etanol brasileira, de baixo custo e alta produtividade, dadas as vantagens existentes junto aos recursos naturais e mão de obra, é destinada principalmente para o mercado norte americano e o mercado europeu. O objetivo geral deste estudo é obter a previsão de produção do etanol brasileiro para exportação entre 2007-2010 através de uma aplicação de Vetores Auto-Regressivos (VAR), a partir das variáveis captadas pelo modelo Mundell-Fleming, Produto Interno Bruto Agropecuário, taxa de juros, câmbio, preço e exportações do etanol. Os resultados apontam para uma tendência crescente de produção iniciada em 2006. A taxa de crescimento da produção prevista de etanol brasileiro para exportação entre 2007-2010 situa-se na ordem de 44,89%.----------------------------------------------Since the beginning of the 21st century, especially the USA and EU have been discussing and promoting the use of specific incentive politics to substitute fossil fuels for renewable sources of biomass origin. In Brazil since the seventies the production of ethanol has been representing an ecological alternative generating employment and income. The production of Brazilian ethanol, of low cost and high productivity, given the existent advantages combined with the natural resources and manual work, is destined mainly for the North American and the European market. The general objective of this study is to obtain the forecast of Brazilian ethanol production for export in the 2007-2010 period through an application of Vector Auto Regression Analysis (VAR), starting from the variables captured by the Mundell-Fleming model, the agricultural gross domestic product, interest rate, exchange, price and ethanol exports. The results appear to have a tendency of growth for the production initiated in 2006. The growth rate of the foreseen Brazilian ethanol production of Brazilian for the export from 2007 to 2010 is about 44.89%.

This work discusses the economic viability of photovoltaic systems usage in distributed generation of electricity and its possible impacts on electrical network. We present the current situation and perspectives of distributed generation in Brazil. Besides that, we developed a financial analysis of grid-tie photovoltaic systems, considering factors such as local solar radiation and conventional energy cost, using data from the National Agency of Electrical Energy (ANEEL). Overall, the usage of photovoltaic systems in Brazil is economically attractive. Despite this, we have to discuss the impacts on the electrical network that might happen due to energy supply variability and economic losses of electric companies and users. However, we show that there is still a lot of room for development of photovoltaic systems in Brazil, especially within regions with high solar radiation.