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Abstract: By integrating renewable energy sources into the existing distribution network, the characteristics and local stability of the network is highly impacted. The network, which was built with the goal of a directed energy flow from large conventional sources connected to the transmission network via the distribution network to consumers, can change the direction of the energy flow. The adoption of environmental commitments and directives encourages the integration of local dispersed energy sources, which can worsen voltage conditions in the distribution network. To avoid excessive local production, distribution network operators must limit the installation of new generati on units, as it is necessary to take into account the quality of power supply by monitoring its network parameters, such as the appropriate voltage profi le and the rati o between acti ve and reacti ve power. On the other hand, excessive loads due to the mass transiti on of household heati ng and transport towards electricity can also pose a problem for high-quality electricity supply due to the excessive voltage drop. The arti cle presents an algorithm for determining the maximum size of unit producti on and the maximum load at a node in the distributi on network. Also demonstrated is the use of variable tap transformer technology, which adjusts the tap of the transformer to provide an appropriate voltage profi le in the network. The enti re analysis was performed on a model of a real medium-voltage network, in which solar and hydropower plants are already included. The model was verifi ed by comparing its calculated values with actual measurements. The goal was to determine the size of the unit’s maximum producti on, as well as the size of the maximum load, by using the diff erenti al evoluti on algorithm, while keeping voltage profi les within the permissible limits. The results of the analysis are presented in the article.
Keywords: distribution network, renewable energy sources, optimisation method, voltage profile
Published in DKUM: 30.10.2023; Views: 113; Downloads: 4
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Abstract: This research paper conducts the process of selecting the criteria that are the most appropriate for a transition from conventional to sustainable warehousing. SWOT analysis is used to emphasise the weaknesses of conventional and the strengths of sustainable warehousing to select the most appropriate for the herein presented study. The results have been verified via a questionnaire filled out by professionals in economics, logistics and warehousing, and mechanical engineering. be added under the methodology section. The results gave the five most important criteria by transforming the conventional into sustainable warehousing. Finally, the paper concluded that renewable energy sources are the most important criteria for transforming by conventional to sustainable warehousing by environmental aspects, as well as the smart technology is above all other criteria by economic aspect. Moreover, providing personal protection equipment and servicing machinery and vehicle on regular basis are the two mainly criteria by social (safety) aspect.
Keywords: logistics, sustainable warehousing, SWOT analysis, renewable energy
Published in DKUM: 13.07.2023; Views: 135; Downloads: 14
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Abstract: The diploma thesis consists of design and numerical simulation of the wind turbine. Geometries are designed according to two theories, the Betz theory and the Schmitz theory. I used Solidworks for 3D modeling of the both rotors. Using Ansys software package, we performed numerical simulations of a rigid body for two different wind speed regimes. We were interested in the angular velocity of the spinning blades, which in combination with moment give us power.
Keywords: Renewable energy, wind energy, numerical simulation, wind turbine, blade design, Betz and Schmitz theory
Published in DKUM: 09.08.2018; Views: 1425; Downloads: 184
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Abstract: Background and Purpose: Currently, the idea of households - prosumers is broadly discussed in public governments, mainly in connection with both the energy security issues and the environmental issues. Therefore, the main goal of this paper is to present new agent model of household - prosumer and to compare two scenarios – “off grid household” and “on grid household”. The additional goal is to evaluate the impact of public support of solar electricity on the economic efficiency of household – prosumer projects (systems). Design/Methodology/Approach: The model is structured as a micro-level agent model, representing one household – prosumer. The model has the following general characteristics: one household with own electricity generation (photovoltaic panels), battery and in case of “on grid household” also connection to the grid. The main goal of the agent is to cover electricity consumption in household with minimal costs. The agent model of prosumer is tested and validated, using the empirical data. Results: The highest level of subsidy has significant impact on the economic indicators of selected scenarios. It causes lower investment costs at the beginning of the project and consequently shorter payback period (3-4 years earlier), positive cumulative cash flow, net present value and IRR in earlier period (approximately 5-10 years earlier, depending on the scenario). Conclusion: We can recommend to the government to continue with current system of subsidies, since it contributes to better economic indicators of particular solar electricity projects. On the other hand, the level of subsidy should be at least the same as in current year 2017, for the purposes of representing the significant part of the investment costs. Low level of subsidy has negligible impact on the economic indicators of households – prosumers projects. The developed agent model is suitable for the evaluation of economic impact of public support on households – prosumers.
Keywords: renewable electricity, photovoltaics, prosumers, households, public support, agent model, energy model
Published in DKUM: 07.05.2018; Views: 1172; Downloads: 389
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Abstract: India, among several other countries globally, now faces a unique situation where managing the energy transition process without hurting the economic development becomes the highlight of its policies. The Indian power sector is highly carbon intensive, with coal based power providing 70% of the total electricity generated. Renewable energy occupies around 15% of the capacity mix. Energy access along with several other challenges, pose an obstacle to the needed transition to clean energy. As the seasonal load variations in India are not prominent, cheap coal based power supplies most of the load profile,while gas power plants are used for peak loads. The myth that renewable energy sources cannot meet baseload demand has become widely accepted and wide-spread, given their fluctuating nature. Several studies demonstrate an optimistic transition to 100% renewable sources might just be possible in the coming decades. In a carbon-rich power sector like India, the ‘base load’ mind set is a pretty big and powerful hurdle, as ensuring base load generation becomes a major issue with implications directly affecting the country’s economy. In this study, an effort has been made to discuss whether base load renewable generation in India is feasible, and the challenges involved.
Keywords: India, base load, renewable generation, energy transition, carbon intensive
Published in DKUM: 11.10.2017; Views: 1107; Downloads: 296
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