10,536 research outputs found

    Emerging materials for transition: A taxonomy proposal from a design perspective

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    In response to environmental challenges, design promotes emerging materials connected with the circular economy and environmental sustainability. However, there is confusion about their definition and contribution to sustainable design and production, showing a gap in their classification. This article proposes a taxonomy as a helpful tool to consolidate and unify terminology, definitions and general understanding of these emerging materials. An analysis of 31 real-world case studies helped outline the taxonomic proposal to formalise knowledge, fostering clarity in classifying and identifying them. The taxonomy aims to organise emerging materials, generate reflections, and encourage their responsible development, diffusion, and adoption

    HI-ACT synthesis report: Interpreting and deliberating hydrogen visions

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    Renewable Energy and Energy Storage Systems

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    The use of fossil fuels has contributed to climate change and global warming, which has led to a growing need for renewable and ecologically friendly alternatives to these. It is accepted that renewable energy sources are the ideal option to substitute fossil fuels in the near future. Significant progress has been made to produce renewable energy sources with acceptable prices at a commercial scale, such as solar, wind, and biomass energies. This success has been due to technological advances that can use renewable energy sources effectively at lower prices. More work is needed to maximize the capacity of renewable energy sources with a focus on their dispatchability, where the function of storage is considered crucial. Furthermore, hybrid renewable energy systems are needed with good energy management to balance the various renewable energy sources’ production/consumption/storage. This work covers the progress done in the main renewable energy sources at a commercial scale, including solar, wind, biomass, and hybrid renewable energy sources. Moreover, energy management between the various renewable energy sources and storage systems is discussed. Finally, this work discusses the recent progress in green hydrogen production and fuel cells that could pave the way for commercial usage of renewable energy in a wide range of applications

    A Greek Green Deal: building energy democracy and fighting energy poverty

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    While implementing the New Green Deal, the European Union is faced with major energy challenges and dilemmas. Energy poverty is an issue of critical importance affecting many Europeans. Since Greece has experienced a prolonged period of crises, the strengthening of energy democracy and the fight against energy poverty must be among the top national priorities. Collective energy actions can pave the way towards the uptake of renewable energy, enabling and incentivizing consumers to become prosumers. This study first outlines the main theoretical perspectives on the politics of energy and proposes a new approach to understand renewable energy. Then it describes the EU energy policy and the transition to a climate-neutral economy. It briefly explains the concept of energy communities before focusing on the case of Greece. The study examines the rise of the country’s energy communities, including the Agrinio and Minoan communities. It also explains the measures taken in Greece during the last decade to tackle energy poverty by offering incentives for energy savings. Moreover, the study describes the national energy and climate plan by examining the case of Tilos. Finally, the study summarises the main findings and offer some policy recommendations

    Optimization for Energy Management in the Community Microgrids

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    This thesis focuses on improving the energy management strategies for Community Microgrids (CMGs), which are expected to play a crucial role in the future smart grid. CMGs bring many benefits, including increased use of renewable energy, improved reliability, resiliency, and energy efficiency. An Energy Management System (EMS) is a key tool that helps in monitoring, controlling, and optimizing the operations of the CMG in a cost-effective manner. The EMS can include various functionalities like day-ahead generation scheduling, real-time scheduling, uncertainty management, and demand response programs. Generation scheduling in a microgrid is a challenging optimization problem, especially due to the intermittent nature of renewable energy. The power balance constraint, which is the balance between energy demand and generation, is difficult to satisfy due to prediction errors in energy demand and generation. Real-time scheduling, which is based on a shorter prediction horizon, reduces these errors, but the impact of uncertainties cannot be completely eliminated. In regards to demand response programs, it is challenging to design an effective model that motivates customers to voluntarily participate while benefiting the system operator. Mathematical optimization techniques have been widely used to solve power system problems, but their application is limited by the need for specific mathematical properties. Metaheuristic techniques, particularly Evolutionary Algorithms (EAs), have gained popularity for their ability to solve complex and non-linear problems. However, the traditional form of EAs may require significant computational effort for complex energy management problems in the CMG. This thesis aims to enhance the existing methods of EMS in CMGs. Improved techniques are developed for day-ahead generation scheduling, multi-stage real-time scheduling, and demand response implementation. For generation scheduling, the performance of conventional EAs is improved through an efficient heuristic. A new multi-stage scheduling framework is proposed to minimize the impact of uncertainties in real-time operations. In regards to demand response, a memetic algorithm is proposed to solve an incentive-based scheme from the perspective of an aggregator, and a price-based demand response driven by dynamic price optimization is proposed to enhance the electric vehicle hosting capacity. The proposed methods are validated through extensive numerical experiments and comparison with state-of-the-art approaches. The results confirm the effectiveness of the proposed methods in improving energy management in CMGs

    Days of autonomy for optimal Battery Sizing in Stand-alone Photovoltaic Systems

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    The main purpose of our article is to optimize the battery sizing by identifying the most appropriate number of autonomy days. A case study has been established and simulated to define the optimal number. In the others current researches, only a small importance has been attributed to the battery autonomy. The objective is generally to ensure a continuous presence of energy especially for isolated systems while this is not always optimal nor economical and does not necessarily guarantee a safe supply. Nevertheless, an over dimensioning of the battery will lead to a consequent cost and a loss of energy. The results show that the number of days of autonomy must correspond to the minimum ratio linking the lack of energy to the surplus during a specific period

    Surface Reactions of Biomass Derived Oxygenates on Lewis Acidic Metal Oxides

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    Lignocellulosic biomass is currently the only source of organic carbon making it a sustainable source for production of liquid hydrocarbon fuels. One main challenge for valorization of biomass is reducing the oxygen content of the starting feedstock and producing high value chemicals. Using heterogeneous catalysts for conversion of biomass feedstock to commodity chemicals is one strategy for the valorization process. Specifically, using Lewis acidic metal oxides for this upgrading process has shown promise due to its ability to catalyze relevant reactions such as isomerization and (retro-) aldol condensation. This work seeks to elucidate the surface interactions of biomass derived oxygenates with solid Lewis acid sites. This is done using in-situ spectroscopic techniques such as Fourier transformed infrared, nuclear magnetic resonance and ultra-violet spectroscopies. These techniques were applied for studying the following reactions: (i) aldol condensation of ethanol and acetaldehyde over reduced molybdenum oxide; (ii) aldol condensation of acetaldehyde over supported molybdenum oxides; (iii) dehydration and retro-aldol condensation of C4 polyoxygenates using various Lewis acidic metal oxides and (iv) ring opening and esterification of erythrose using various Lewis acidic metal oxides. Surface properties such as Lewis and Brønsted acid site and reducibility of metal center are essential to rationalizing the reaction pathway of the above reactions. The aforementioned studies provide fundamental knowledge regarding how different oxygenates can interact with solid Lewis acid sites.Ph.D

    Innovation in Energy Security and Long-Term Energy Efficiency â…ˇ

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    The sustainable development of our planet depends on the use of energy. The increasing world population inevitably causes an increase in the demand for energy, which, on the one hand, threatens us with the potential to encounter a shortage of energy supply, and, on the other hand, causes the deterioration of the environment. Therefore, our task is to reduce this demand through different innovative solutions (i.e., both technological and social). Social marketing and economic policies can also play their role by affecting the behavior of households and companies and by causing behavioral change oriented to energy stewardship, with an overall switch to renewable energy resources. This reprint provides a platform for the exchange of a wide range of ideas, which, ultimately, would facilitate driving societies toward long-term energy efficiency
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