2,308 research outputs found

    Masdar - The Sustainable Desert City: A Theoretical Mirage or A Realistic

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    Masdar City, currently being developed in Abu Dhabi and designed by Foster + Partners, a high-profile British firm of architects, sets a groundbreaking example of a new breed of eco-cities. The city’s birth has taken on an environmental stance. Having recently completed its first phase of construction, the emphasis of the development is principally based on sustainability, using traditional walled city planning and existing technology to achieve a net zero-carbon and zerowaste development. To achieve carbon-neutrality, the design team has employed a series of innovative environmental design strategies and integrated planning principles. This paper presents these strategies and discusses the project in relation to its social, economical and environmental contexts, and considers prospects for the viability of building in the desert and its global impact on sustainable urban development of the futur

    Grey-Box Modeling for Photo-Voltaic Power Systems Using Dynamic Neural-Networks

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    There exists various ways of modeling and forecasting photo-voltaic (PV) systems. These methods can be categorized, in board-way, under either definite equations models (white or clear-box) or heuristic data-driven artificial intelligence models (black-box). The two directions of modeling pose a number of drawbacks. To benefit from both worlds, this paper proposes a novel method where clear-box model is extended to a grey-box model by modeling uncertainities using focused time-delay neural network models. The grey-box or semi-definite model was shown to exhibit enhanced forecasting capabilities

    Theorizing Collective Green Actions

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    The notion of “green” has gained increasing attention over the years. Many major companies have made significant attempt to better fit into the green concept. Are these corporate marketing endeavors purely based on their environmental consciousness or driven by their intention to gain social recognition which could in turn reshape their corporate image that better reflects the concerns of environments, climate change, and green IT issues? This question is interesting to explore because the complexity and difficulty of ‘green endeavor’ has been widely addressed among practitioners and researchers. Based on an institutional perspective, this paper thus proposes a theoretical framework that helps organizations analyze these green issues in the competitive marketplaces. Propositions of the framework theorize that organizations will inevitably face various isomorphic pressures that lead them to initiate or follow green actions collectively. Those isomorphic pressures usually stem from influential agencies or initiatives in their respective fields such as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), the Green Grid, Health Insurance Portability and Accountability Act (HIPAA), and European Waste Catalogs (EWC). The implications of this theoretical framework suggest that organizations need to undertake green actions shiftily in order to continuously validate their competitive status in the global, networked economy. The cost of failing to do so, i.e. being ‘not’ green, might be beyond any organization’s measure in the long term. Further implications of collective green actions are made to the UAE local industries and research community

    Automated Transit Networks (ATN): A Review of the State of the Industry and Prospects for the Future, MTI Report 12-31

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    The concept of Automated Transit Networks (ATN) - in which fully automated vehicles on exclusive, grade-separated guideways provide on-demand, primarily non-stop, origin-to-destination service over an area network – has been around since the 1950s. However, only a few systems are in current operation around the world. ATN does not appear “on the radar” of urban planners, transit professionals, or policy makers when it comes to designing solutions for current transit problems in urban areas. This study explains ATN technology, setting it in the larger context of Automated Guideway Transit (AGT); looks at the current status of ATN suppliers, the status of the ATN industry, and the prospects of a U.S.-based ATN industry; summarizes and organizes proceedings from the seven Podcar City conferences that have been held since 2006; documents the U.S./Sweden Memorandum of Understanding on Sustainable Transport; discusses how ATN could expand the coverage of existing transit systems; explains the opportunities and challenges in planning and funding ATN systems and approaches for procuring ATN systems; and concludes with a summary of the existing challenges and opportunities for ATN technology. The study is intended to be an informative tool for planners, urban designers, and those involved in public policy, especially for urban transit, to provide a reference for history and background on ATN, and to use for policy development and research

    Identifying opportunities for developing CSP and PV-CSP hybrid projects under current tender conditions and market perspectives in MENA – benchmarking with PV-CCGT

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    Concentrating solar power (CSP) is one of the promising renewable energy technologies provided the fact that it is equipped with a cost-efficient storage system, thermal energy storage (TES). This solves the issue of intermittency of other renewable energy technologies and gives the advantage of achieving higher capacity factors and lower levelized costs of electricity (LCOE). This is the main reason why solar tower power plants (STPP) with molten salts and integrated TES are considered one of the most promising CSP technologies in the short term [1]. On the other hand, solar photovoltaic (PV) is a technology whose costs have been decreasing and are expected to continue doing so thus providing competitive LCOE values, but with relatively low capacity factors as electrical storage systems remain not cost-effective. Combining advantages and eliminating drawbacks of both technologies (CSP and PV), Hybridized PV-CSP power plants can be deemed as a competitive economic solution to offer firm output power when CSP is operated smartly so that its load is regulated in response to the PV output. Indeed previous works, have identified that it would allow achieving lower LCOEs than stand-alone CSP plants by means of allowing it to better utilize the solar field for storing energy during the daytime while PV is used [1]. On the fossil-based generation side, the gas turbine combined cycle (CCGT) occupies an outstanding position among power generation technologies. This is due to the fact that it is considered the most efficient fossil fuel-to-electricity converter, in addition to the maturity of such technology, high flexibility, and the generally low LCOE, which is largely dominated by fuel cost and varies depending on the natural gas price at a specific location. Obviously, the main drawback is the generated carbon emissions. In countries rich in natural gas resources and with vast potential for renewable energies implementation, such as the United Arab Emirates (UAE), abandoning a low LCOE technology with competitively low emissions – compared to coal or oil - and heading to costly pure renewable generation, seems like an aggressive plan. Therefore, hybridizing CCGT with renewable generation can be considered an attractive option for reducing emissions at reasonable costs. This is the case of the UAE with vast resources of both natural gas and solar energy. Previous work have shown the advantages of hybrid PV-CCGT and hybrid PV-CSP plants separately [1][2]. In this thesis, CSP and the two hybrid systems are compared on the basis of LCOE and CO2 emissions for a same firm-power capacity factor when considering a location in the UAE. The results are compared against each other to highlight the benefits of each technology from both environmental and economic standpoints and provide recommendations for future work in the field. The techno-economic analysis of CSP (STPP with TES), PV-CSP(STPP with TES) and PV-CCGT power plants have been performed by DYESOPT, an in-house tool developed in KTH, which runs techno-economic performance evaluation of power plants through multi-objective optimization for specific locations[1]. For this thesis, a convenient location in the UAE was chosen for simulating the performance of the plants. The UAE is endowed by the seventh-largest proven natural gas reserves and average to high global horizontal irradiation (GHI) and direct normal irradiation (DNI) values all year round, values considered to be lower than other countries in the MENA region due to its high aerosol concentrations and sand storms. The plants were designed to provide firm power in two cases, first as baseload, and second as intermediate load of 15 hours from 6:00 until 21:00. The hours of production were selected based on a typical average daily load profile. CSP and PV-CSP model previously developed by [3][1] were used. Ideally in the PV-CSP model, during daytime hours the PV generation is used for electricity production, covering the desired load, while CSP is used partly for electricity production and the rest for storing energy in the TES. Energy in the TES system is then used to supply firm power during both periods of low Irradiance and night hours or according to need. A PV-CCGT model has been developed which operates simultaneously, prioritizing the availability of PV while the CCGT fulfils the remaining requirement. There is a minimum loading for the CCGT plant which is determined by the minimum possible partial loading of the gas turbine restricted by the emission constraints. Accordingly, in some cases during operation PV is chosen to be curtailed due to this limitation. The main results of the techno-economic analysis are concluded in the comparative analysis of the 3 proposed power plant configurations, where the PV-CCGT plant is the most economic with minimum LCOE of 86 USD/MWh, yet, the least preferable option in terms of carbon emissions. CSP and PV-CSP provided higher LCOE, while the PV-CSP plant configuration met the same capacity factor with 11% reduction in LCOE, compared to CSP

    A Net Energy-based Analysis for a Climate-constrained Sustainable Energy Transition

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    The transition from a fossil-based energy economy to one based on renewable energy is driven by the double challenge of climate change and resource depletion. Building a renewable energy infrastructure requires an upfront energy investment that subtracts from the net energy available to society. This investment is determined by the need to transition to renewable energy fast enough to stave off the worst consequences of climate change and, at the same time, maintain a sufficient net energy flow to sustain the world's economy and population. We show that a feasible transition pathway requires that the rate of investment in renewable energy should accelerate approximately by an order of magnitude if we are to stay within the range of IPCC recommendations

    Absence of Structural Impact of Noble Nanoparticles on P3HT: PCBM Blends for Plasmon Enhanced Bulk-Heterojunction Organic Solar Cells Probed by Synchrotron Grazing Incidence X-Ray Diffraction

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    The incorporation of noble metal nanoparticles, displaying localized surface plasmon resonance, in the active area of donor-acceptor bulk-heterojunction organic photovoltaic devices is an industrially compatible light trapping strategy, able to guarantee better absorption of the incident photons and give an efficiency improvement between 12% and 38%. In the present work, we investigate the effect of Au and Ag nanoparticles blended with P3HT: PCBM on the P3HT crystallization dynamics by synchrotron grazing incidence X-ray diffraction. We conclude that the presence of (1) 80nm Au, (2) mix of 5nm, 50nm, 80nm Au, (3) 40nm Ag, and (4) 10nm, 40nm, 60nm Ag colloidal nanoparticles, at different concentrations below 0.3 wt% in P3HT: PCBM blends, does not affect the behaviour of the blends themselves

    spotlight europe 2010/10, November 2010: The Middle East as a region of opportunity

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    The Middle East is more than a hotbed of conflict, war and terror. It is time the EU woke up to the opportunities this region has to offer. The four Es - economy, energy, environment and education-suggest numerous areas of cooperation in which Europe can become profitably involved. Furthermore, the six GCC states ought to play a greater role in the resolution of regional conflict

    ZERO CARBON CITY- MASDAR CITY CRITICAL ANALYSIS

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    Climate has a direct impact on the performance of buildings and their energy consumption especially in hot arid areas. In these areas, the lack of water and energy sources forces people to build their houses with several strategies, based on minimum energy consumption as using the environment natural climatic strategies for coping with harsh conditions as vernacular architecture. In order to apply and achieve sustainable building in hot and humid climates, efforts must be put into understanding the local climate, and integrating appropriate building technologies into the architectural and urban designs. Today, the continuous progress in technologies offered new means towards achieving comfortable climatic conditions and efficiency in building. But these technologies result in high building costs, maintenance and depletion of renewable resources. The paper aim is to investigate the feasibility of using new technologies as nanotechnology beside other passive design strategies in desert zones .In addition to, assessing their adaption towards the extreme and harsh climatic conditions of the hot arid zones and their efficiency. The paper will illustrate the advantages and disadvantages of applying new technologies and materials to achieve sustainability in hot arid zones through analyzing Masdar City in United Arab of Emirates. The paper suggests that Masdar City still didn’t achieve its goals and failed to be a model of urban environmental sustainability, to be replicated in other countries
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