1. The impact of financial support mechanisms and geopolitical factors on the profitability of investments in solar power plants in SloveniaIztok Gornjak, Filip Kokalj, Niko Samec, 2024, original scientific article Abstract: This article examines the impact of financial support mechanisms and geopolitical factors on the profitability of investments in solar power plants within Slovenia. The European Union’s energy policy prioritizes increases in renewable energy sources, aiming to reduce dependency on unstable and volatile fossil fuel markets. Solar power plants play a vital role in this transition. The energy policy framework also includes mechanisms and support systems to operate such facilities. This article analyzes electricity price trends over the past decade and addresses which support type—guaranteed purchase or operational support—has proven more profitable for investments in solar power plants up to 50 kW in Slovenia, considering economic and geopolitical influences on the electricity market. Although the global energy market has been affected by various significant events in recent years, it was found that the COVID-19 pandemic had minimal impact on the electricity market. In contrast, the onset of the conflict in Ukraine has contributed to rising electricity prices and has influenced the support dynamics essential for the development and sustainability of renewable energy systems. Analyses from the past decade indicate a higher return on investment in solar power plants when operational support mechanisms are chosen over guaranteed purchase support. Keywords: renewable energy sources, solar power plants, support system, investment profitability factors, electricity price Published in DKUM: 16.12.2024; Views: 0; Downloads: 6
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2. Quantifying power system frequency quality and extracting typical patterns within short time scales below one hourYounes Mohammadi, Boštjan Polajžer, Roberto Chouhy Leborgne, Davood Khodadad, 2024, original scientific article Keywords: quantifying power system frequency quality, statistical indices, pattern extracting, machine learning, short time scales, renewable energy sources Published in DKUM: 23.08.2024; Views: 50; Downloads: 5
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3. Towards productive and ergonomic order picking : multi-objective modeling approachBrigita Gajšek, Simona Šinko, Tomaž Kramberger, Marcin Butlewski, Eren Özceylan, Goran Đukić, 2021, original scientific article Abstract: The logistics sector should strive for sustainability alongside productivity by protecting its order pickers' health and welfare. Existing storage assignment models are mainly based on the criterion of order picking time and, to a lesser extent, the human factor. In the paper, a solution to a storage assignment problem using a multi-objective model based on binary integer linear programing is presented by developing a solution that considers order picking time, energy expenditure and health risk. The Ovako Working Posture Assessment System (OWAS) method was used for health risk assessment. The downside of solely health risk-optimization is that the average order picking time increases by approximately 33 % compared to solely time-optimization. Contrary to this, the developed multi-objective function emphasizing time has proven to be promising in finding a compromise between the optimal order picking time and eliminating work situations with a very-high risk for injuries. Its use increases the time by only 3.8 % compared to solely time-optimization while significantly reducing health risk. Keywords: productivity, energy expenditure, order picking, order picking system, health risk, OWAS, multi-objective modeling, planning, logistics, ergonomics Published in DKUM: 13.08.2024; Views: 109; Downloads: 10
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4. Comparative analysis of batteries for photovoltaic systems : bachelor's thesisKristina Gočanin, 2023, undergraduate thesis Abstract: Renewable energies represent unlimited power sources that are significantly reducing greenhouse emissions. The possibilities and advantages of abundantly available solar energy are immense. However, some challenges are preventing solar energy from reaching its full potential regarding its efficiency and energy storage. Therefore, the main focus of this thesis is on electrochemical storage systems. The aim is to compare the currently leading technology – Li-ion battery to the most recent breakthrough in storage systems – the solid-state battery. The thesis includes a comparative analysis of the mentioned technologies, as well as the theoretical part that introduces solar energy and photovoltaic systems with their main components. Keywords: photovoltaic system, energy storage, analysis, Li-ion battery, solid-state battery Published in DKUM: 30.01.2024; Views: 457; Downloads: 47
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5. Solar photovoltaic tracking systems for electricity generation : a reviewSebastijan Seme, Bojan Štumberger, Miralem Hadžiselimović, Klemen Sredenšek, 2020, review article Abstract: This paper presents a thorough review of state-of-the-art research and literature in the field of photovoltaic tracking systems for the production of electrical energy. A review of the literature is performed mainly for the field of solar photovoltaic tracking systems, which gives this paper the necessary foundation. Solar systems can be roughly divided into three fields: the generation of thermal energy (solar collectors), the generation of electrical energy (photovoltaic systems), and the generation of electrical energy/thermal energy (hybrid systems). The development of photovoltaic systems began in the mid-19th century, followed shortly by research in the field of tracking systems. With the development of tracking systems, di%erent types of tracking systems, drives, designs, and tracking strategies were also defined. This paper presents a comprehensive overview of photovoltaic tracking systems, as well as the latest studies that have been done in recent years. The review will be supplemented with a factual presentation of the tracking systems used at the Institute of Energy Technology of the University of Maribor. Keywords: solar energy, photovoltaic tracking system, tracking strategies, drive system, degree of freedom Published in DKUM: 15.11.2023; Views: 436; Downloads: 36
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8. Combustion of municipal solid waste for power productionFilip Kokalj, Niko Samec, 2013, independent scientific component part or a chapter in a monograph Keywords: gospodarjenje z odpadki, zgorevanje, waste management, municipal solid waste, integrated waste management system, waste-to-energy, thermal treatment, waste-to-energy plant, computational fluid dynamics Published in DKUM: 10.07.2015; Views: 2227; Downloads: 97
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9. A fuzzy model of power supply system controlJanez Usenik, 2012, original scientific article Abstract: In this article, a mathematical model of control of a dynamic system is described; one such system could be a power supply system. Analytical approaches that have been developed to describe the influence of production and stock, i.e. additional capacities, require a hierarchical spatial pattern and demand. Demand is usually an inherently stochastic process, but in this article we simulate it as an output fuzzy variable in a fuzzy system, in which all the input variables are also fuzzy. Furthermore, an interesting use of neural sets is shown, which is presented as an efficient method for the optimisation of the fuzzy system. At the end, a numerical example is given. Keywords: power supply system, energy capacities, demand, fuzzy logic, neural net Published in DKUM: 10.07.2015; Views: 2472; Downloads: 32
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10. ENERGY MANAGEMENT AS A TOOL FOR ENERGY EFFICIENCY IN THE COMPANY KOPUN SIMTO Ltd.Kaja Černjavič, 2013, master's thesis Abstract: The problem we referred to is great and mostly uncontrolled energy consumption in the public and private sector not just in Slovenia but also in other countries around the world. In Europe some restrictions were met, which resulted in 2009 in a new standard, the EN 16001:2009, two years later the International Standardization Body issued the ISO 50001:2011, energy management standard.
With the help of a case study potential in energy and emissions as well as overall environmental protection was presented. All anticipated research methods were followed, hypothesises set in the introduction were carefully researched and mainly proven to be right whereas some, hypothesis one and two, connected with the increase of energy consumption in Slovenia and hypothesis two, number of certificates per capita, were refuted. The overall consumption of energy in Slovenia decreased (table 2, page 15) in the year 2011 compared to 2010. Slovenia is also not the country with the lowest number of issued energy certificates per capita; Portugal has two (picture 1, page 35).
Hypothesises three to five linked to the study case were fully proven to be right; the company did not have an energy management programme but the owners were fully aware of the possibilities of energy savings. There was as well energy savings potential, proven to be even more that the first anticipated 50-percent.
Our conclusion is that energy management plays a key role in sustainable development and environment conservation practices, as it helps the country move towards an energy efficient economy. With the help of the case study we made a good illustration how a micro company saved 75-percent of energy costs in the first year, by using energy management as a tool. The main and general changes enhanced the company’s energy efficiency, taught employees some basic techniques for achieving greater energy efficiency and cost reduction not just inside the organization but also in family homes. It is important, that expenditures concerning energy purchase and consumption are exactly defined. Before the implementation and certainly after it, energy management accounting and energy management audits should be performed. This serves as a tool to realize and understand the full spectrum of the environmental costs and helps to create internal demand in businesses for cleaner and less wasteful production processes. It gives organizations a preferential position to engage in pollution prevention activities mainly because it makes good business sense due to the immediate financial benefits it delivers.
The prime goal of the thesis was to stimulate organizations to implement the concepts of energy management practices into their organizational structure and to use energy management systems for lowering energy and other environmental costs, no matter the size or segment the organization. There is no need to get certified if not wanted; just performing these activities is enough, as it brings all the benefits to the environment. Helping to achieve this goal is now mainly in the hands of others, it is important how the country will act and react and help organizations to achieve this goal. Different restrictions can be met on the field of law and taxes, subsidies, etc.
We believe that, for meeting all the required goals (Kyoto protocol and other) and help the economy to move towards a sustainable one, organizations will have to reorganize their structures and implement energy management. There are big potentials in reduction of emissions and energy consumption, with energy management, organizations can get the help and knowledge how to keep the budget of energy consumption as low as possible, how to meet all the critical objectives and also important, reduce their operational costs on a long-term basis. Keywords: energy management, energy efficiency, energy conservation, energy consumption, energy accounting and auditing, energy manager, International Standards Organization (ISO), energy management system EnMS, cost efficiency Published in DKUM: 19.05.2014; Views: 2189; Downloads: 136
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