h i g h l i g h t sOil obtained by SE has the lowest energy and CO 2 values per MJ prod . Oil obtained by SFE proved to be more economically viable, with a cost of 365 €/kg oil . Biorefinery 2 (biodiesel SFE + bioH 2 ) has the best energy/CO 2 /economy compromise. The bioH 2 as co-product may be advantageous in terms of product yield or profit. High-value pigments can be produced by SFE which is a clean technology. Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH 2 ). The energy consumption and CO 2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH 2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJ prod, and CO 2 emissions, 13-15 kgCO 2 /MJ prod . Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365€/kg oil produced and simultaneously extracting high-value pigments. The bioH 2 as co-product may be advantageous in terms of product yield or profit.
This paper brings together several contemporary topics in energy systems aiming to provide a literature review based reflection on how several interrelated energy systems can contribute together to a more sustainable world. Some directions are discussed, such as the improvement of the energy efficiency and environmental performance of the systems, the development of new technologies, the increase of the use of renewable energy sources, the promotion of holistic and multidisciplinary studies, and the implementation of new management rules and "eco-friendly and sustainable" oriented policies at different scales. The interrelations of the diverse energy systems are also discussed in order to address their main social-economic-environmental impacts. The subjects covered include the assessment of the electricity market and its main players (demand, supply, distribution), the evaluation of some urban systems (buildings, transportation, commuting), the analysis of the implementation of renewable energy cooperatives, the discussion of the diffusion of the electric vehicle and the importance of new bioenergy systems. This paper also presents relevant research carried out in the framework of both the Energy for Sustainability Initiative of the University of Coimbra and the Sustainable Energy Systems focus area of the MIT-Portugal Program. To conclude, several research topics that should be addressed in the near future are proposed.
Advanced biofuels, such as those obtained from microalgae, are widely accepted as better choices for achieving goals of incorporating renewables and non-food fuel sources into the transportation sector, and for overcoming land use issues due to biofuel crops. Main challenges are currently the feasibility of large-scale commercialization of microalgae biofuels, since there are still some technical problems to overcome (e.g. the high energy consumption associated with biomass processing) and the majority of economic and financial analyses are based on pilot-scale projects. Therefore, this article presents the results of a Delphi study aiming to identify the main obstacles and most critical issues affecting the potential of large-scale commercialization of microalgae biodiesel and its incorporation into the fuel market. According to the authors' knowledge, this is the first Delphi study with this objective. The respondents are worldwide market specialists in the survey themes that ranged from biofuels economics to their environmental sustainability. One of the key findings is that most of the experts believe that production of microalgae biofuels will achieve its full commercial scale until 2020, and that from 2021 till 2030 it could represent from 1% to 5% of the worldwide fuel consumption. The study results also showed that environmental issues are where expert opinion differs more.
a b s t r a c tThe need to develop innovative technologies that could replace fossil fuels and, consequently contribute to the reduction in emissions of greenhouse gases is now clear. In this circumstance, algal biofuels are generating considerable interest around the world. The purpose of this study is to provide an integrated assessment of microalgae potential as a source of biofuels, while comparing its costs with that from other emerging biofuel technologies. This article emphasizes the importance of emerging United States and European Union energy policies that will encourage the development of innovative, and sustainable technologies in their respective regions. An ample review of the scientific literature was carried out, contributing to the analysis of cost, economic and technical indicators. The results obtained allowed the detection of important gaps of information that need to be filled, in order to guide future investment decisions concerning this rising technology.
Nas últimas décadas, é possível verificar uma intensa migração da população mundial de áreas rurais para urbanas, gerando congregações de pessoas e diversas dificuldades relacionadas à gestão das cidades. Assim, os grandes centros urbanos apresentam inúmeros problemas relativos à gestão de resíduos e energia, escassez de recursos, poluição do ar, problemas de saúde humana e congestionamentos. Para mitigar estes problemas, uma alternativa é o desenvolvimento e utilização de tecnologias com foco na sustentabilidade. Assim, o presente artigo tem por objetivo identificar e analisar estratégias que contribuam para que as cidades tornem-se inteligentes através da utilização de Tecnologias de Informação e Comunicação (TICs), visando uma melhoria na sustentabilidade. Os resultados demonstram que a implantação de tecnologias nas cidades pode contribuir com questões relacionadas ao monitoramento e gerenciamento de serviços e infraestruturas, facilitando a gestão das cidades e garantindo o aumento da qualidade de vida da população.
Innovative technologies and sources of energy must be developed to replace fossil fuels and contribute to the reductions of emissions of greenhouse gases associated with their use. In this perspective, algal biofuels are generating substantial awareness in many countries. As of today, it has been shown that it is scientifically and technically possible to derive the desired energy products from algae in the laboratory. The question lies, however, in whether it is a technology that merits the support and development to overcome existing scalability challenges and make it economically feasible. In this context, the overall purpose of this study is to provide an integrated assessment of the potential of microalgae as a source to produce biofuels, while confronting it with competing emerging biofuel technologies. It is intended to provide a comprehensive state of technology summary for producing fuels from algal feedstocks and to draw some insights upon the feasibility and technoeconomic challenges associated with scaling up of processes.
If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. Purpose -Currently, experimental and theoretical work is being performed to ensure that biofuels from microalgae become a reality. However, there is a considerable number of discussions concerning in which processes should be focussed efforts of research and development. The purpose of this paper is to provide decision support not only to help build guidelines of research to be undertaken, but also to contribute to the design of more adequate policy and funding instruments. The key objective of this study is to determine the prospects of employing microalgae into the production of biofuels within a time scale extending to 2030. Design/methodology/approach -The Delphi method is a qualitative research aiming to support strategic future-oriented action, such as policy making in the areas of science and technology. It is especially appropriate in judgment and long-range forecasting (20-30 years) situations, when expert opinions are often the only source of information available, due to a lack of appropriate historical, economic or technical data. Findings -The Delphi method proved to be a successful research method when expert opinions are the main source of information available, due to a lack of appropriate historical, economic or technical data and the outcomes provided a clear outline of the main issues of microalgae biofuels' market at present and in the future.Research limitations/implications -The outcomes might not represent the majority of the microalgae experts' opinion due to the sample size. Originality/value -The work presented in this paper is especially original. According to the authors' knowledge, this is the first qualitative Delphi study related to algae biofuels.
The buildings' sector accounts for a large share of energy consumption on a global scale. This scenario generates the need to design and construct more efficient buildings and also requires new policies and incentives. The greatest opportunities for integrating energy efficiency strategies in construction occur at the design stage, in which decisions that will have significant impacts on the building's life cycle are taken. Therefore, the use of Building Information Modeling (BIM) is considered, as well as parametric design: new design technologies that allow the analysis of multiple scenarios to support the decisions during the design stage. The purpose of this study is to provide, through a literature analysis, an overview about practical applications of BIM and parametric design for buildings' energy efficiency in a recent research scenario. Studies were categorized according to their main approach and the main software used. In addition, benefits provided by the use of the technologies adopted were highlighted.
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