Методика обоснования технических и экономических параметров сетевой ветроэлектрической станции для условий Сирии

Wind energy is one of the fastest-growing sources of electricity in India and around the world. In spite of being cheap, clean and abundant the continuous fluctuations in the renewable energy causes significant power quality issues. This paper presents a technical review of power quality problems associated with grid connected wind power plant and describes the Dynamic Voltage Restorer that injects voltage into the system with a view to enhance the network power factor while stabilizing the voltage and reducing the network losses. On the basis of measurements and norms followed according to the guidelines specified in IEC-61400 (International Electro-technical Commission) standard, the performance of the wind turbine and thereby power quality should be determined. Wind turbines, especially of Induction type, can draw large amount of reactive power from the grid. Insufficient supply of reactive power from the grid to the wind generators may cause voltage stability problems. To minimize reactive power exchange between wind generators and grid, dynamic compensation of reactive power can be employed by using DVR. This paper also describes the analysis of Dynamic Voltage Restorer (DVR) using MATLAB/SIMULINK for the grid connected Wind Power Plant.

A holistic techno-economic feasibility analysis of residential renewable energy systems: An insight into Turkish case

This article presents a framework to integrate and optimize the design of large-scale wind turbines. Annual energy production, load analysis, the structural design of components and the wind farm operation model are coupled to perform a system-level nonlinear optimization. As well as the commonly used design objective levelized cost of energy (LCoE), key metrics of engineering economics such as net present value (NPV), internal rate of return (IRR) and the discounted payback time (DPT) are calculated and used as design objectives, respectively. The results show that IRR and DPT have the same effect as LCoE since they all lead to minimization of the ratio of the capital expenditure to the energy production. Meanwhile, the optimization for NPV tends to maximize the margin between incomes and costs. These two types of economic metrics provide the minimal blade length and maximal blade length of an optimal blade for a target wind turbine at a given wind farm. The turbine properties with respect to the blade length and tower height are also examined. The blade obtained with economic optimization objectives has a much larger relative thickness and smaller chord distributions than that obtained for high aerodynamic performance design. Furthermore, the use of cost control objectives in optimization is crucial in improving the economic efficiency of wind turbines and sacrificing some aerodynamic performance can bring significant reductions in design loads and turbine costs.

This study determines the voltage across insulators after a direct lightning strike to an overhead ground wire on a 24 kV pole structure for different grounding distances of overhead ground wire, to calculate the maximum ground resistance required to avoid disruption of the distribution line system using ATP-EMTP software. The results show that when a 40 kA lightning current, the average lightning current in Thailand, strikes a 24 kV pole structure, the maximum ground resistance should not exceed 4 Ω for a 40 m grounding distance of overhead ground wire, based on an existing critical insulator flashover of 205 kV. However, because the average ground resistance in Thailand is approximately 10 Ω, this study proposes increasing the insulation level from 205 kV to 300 kV to reduce the likelihood of power outage. The cost-effectiveness of such an investment is assessed in terms of net present value (NPV), internal rate of return (IRR), profitability index (PI), and discounted payback period (DPP) using existing economic tools. Results show that when the critical insulator flashover is increased from 205 kV to 300 kV for a 40 m grounding distance of overhead ground wire, the project is likely to have a DPP of 15.12 years, NPV of 143,321.87 USD, IRR of 12%, and PI of 1.15. On the other hand, grounding distances greater than 40 m for overhead ground wire result in negative NPV, although the back flashover rate can be reduced by 1.51–5.71% with grounding distances of 80–200 m compared to the situation in the absence of grounding.

Integrated Economic Adoption Model for residential grid-connected photovoltaic systems: An Australian case study

A financial feasibility model of gasification and anaerobic digestion waste-to-energy (WTE) plants in Saudi Arabia

Advanced control of large-scale wind turbines: Structural load reduction and lifetime control

Summary. The article proposes a financial model for a motor vehicle service enterprise and provides examples of its application. Research object: the operational process of a motor vehicle service enterprise. Purpose of the article: to develop an adapted financial model for motor vehicle service enterprises, enabling the assessment of startup prospects, strategic planning, and business development. The authors propose a comprehensive approach that considers revenues, expenses, cash flows, and investment attractiveness. Research methods: mathematical modeling of processes. The proposed financial model enables the evaluation of the feasibility of investment projects for establishing a motor vehicle service enterprise or improving specific aspects of its operations. Using the model, economic efficiency indicators that do not consider the time factor can be assessed, including: profit margin, payback period of initial investments, project profitability, as well as indicators for projects requiring a significant time frame. In such cases, time-sensitive indicators are used, such as net present value (NPV), discounted payback period, and internal rate of return (IRR). Calculations of some of these indicators are provided earlier in the article. Key aspects of the financial model: 1) forecasting revenues and expenses: estimation of the annual production program, labor intensity, revenues, and expenses to justify economic feasibility; 2) efficiency analysis: the methodology includes calculating indicators such as net profit, profitability, break-even point, and project payback period; 3) risk assessment: applying sensitivity analysis to identify key factors affecting profitability. Results: 1) the model allows for analyzing projects with varying levels of risk and incorporates the time factor; 2) the model facilitates the determination of economic efficiency using indicators such as net present value (NPV), internal rate of return (IRR), as well as indicators that do not account for discount rates. Practical significance: the research results are of practical value for auto service enterprises. Forecasting based on the model helps substantiate investments, optimize costs, and ensure business stability. Research prospects: further studies aim to enhance the model, develop methods for risk assessment, and improve forecasting depending on changes in economic conditions. Key conclusions: 1) the financial model is an effective tool for managerial decision-making; 2) the integration of economic efficiency evaluation methods reduces investment risks and optimizes the activities of auto service enterprises. Keywords: motor vehicle service enterprise, financial model, revenue, expenses, profit, efficiency, margin, payback period, net present value, risks, break-even point.

While the global demand for energy continues to grow, the world’s depots of fossil fuels decrease. Logically, scientists have researched in different ways of creating sustainable energy. Dams, solar power and wind energy are all different ways of extracting power from nature. Having neither mountains nor many hours of annual sunshine, Denmark is, however, a flat country with many kilometers of coast line and calm weather, and therefore is perfectly suited for wind energy. Because of these facts, Denmark has always been a pioneer within the wind industry, building the world’s first off-shore wind energy park in 1991. In recent years, wind turbines have grown dramatically in size and capacity. Scientists predict that in order to make wind energy a more suitable alternative to fossil fuels, the wind turbines have to become even larger. The major problem with these super wind turbines, however, is the weight of the nacelle, of which a heavy part is the gear box. In order to avoid having a gear box in the wind turbine, a direct driven generator has been proposed, where superconductors play an important role. Energy losses due to Joule heating will be eliminated and high temperature superconductors are capable of working in high magnetic fields (several Teslas). The alternative to superconductors are permanent magnets, but the required amount would become expensive and inaccessible, while superconductors can be made from easily accessible elements. However, using superconductors also pose considerable challenges; low temperature cooling systems are required and the superconductors need to be of high quality. High temperature superconductors is a relatively new field of study, with the first discoveries made in the 1980s. Having found materials with superconducting properties at relatively high temperatures, the issue of optimizing other properties arose. A pinning center is an irregularity in the crystal, which destroys the superconducting properties. Here the magnetic field lines can penetrate without causing further damage to the superconductor. In 2005 Misko et al. found that a gradient in density of pinning centers could increase the critical current density (Jc) in a magnetic field. Pinning centers had been known to optimize superconductors, but with this new information, scientists have been equipped with a new tool to make superconductors more suitable for wind turbines. Since Misko et al. first predicted that different pinning densities throughout the superconductor could improve superconductors; many attempts have been made in order to show this property experimentally. Different methods to create the desired pinning patterns experimentally include Molecular Beam Epitaxy and E-beam Lithography. These methods are, however, both very expensive, making them less attractive for industrial production. This project investigates different options of creating simple gradients in the pinning center density.

There is mounting evidence that the global warming and, consequently, the climate changes are anthropogenic and attributed to fossil fuel consumption. Therefore, it is mandatory to find alternative solutions that can replace current resources. One of those resources is solar energy, and specifically Photovoltaic solar panels. Qatar is a sun-belt country with daily average solar radiation in the range of 5.1 kWh/m2. Namely, in such hot and dry region, solar energy seems to be the most important source of renewable energy. The local government has been aware of this fact and planning to generate 200 MW of electricity in 2020 from solar power. In hot country like Qatar air conditioning systems account for more than 65% energy consumption. This provides the challenge to study the possibility of utilizing renewable energy in air conditioning sector. In the light of the improvements achieving in the performance of photovoltaic systems beside the reduction in its price, the combination between the photovoltaic and air conditioning systems is becoming more practical. Unlike other renewable energy resources, the maximum available solar energy corresponds with the peak cooling demand. This increases the viability of utilizing solar energy in air conditioning applications. The current work demonstrates the technical and economic potential of utilizing solar energy at the working conditions of Qatar. For this aim a most common mosque design in Doha, Qatar, was selected as a case study. Among the different solar module brands available in the market, Solar Leading module brand was considered. Two simulation models including hourly analysis program and system advice model were used in order to carry out the technical and economic analysis. From technical viewpoint, current study resulted in determination of required number of a considered PV module which has been found to be 77 panels. These panels can provide the air conditioning system of the considered mosque with annual electricity demand the A/C system, see Figure 1. The objective of the economic analysis is to determine the costs and the benefits of investment and to quantify with the determination of appropriate financial indicators the economic convenience of PV systems. In particular the economic analysis resulted in determination of different figures of merit including net present value (NPV), internal rate of return (IRR), the payback time (PBT), and levelized cost of electricity (LCOE). The NPV, IRR, PBT, and LCOE were found to be $3700, 3.8%, 22 years, and 0.070 $/KWh, respectively, see Figure 2. The obtained results show that utilization of solar energy for air conditioning purposes has big potential for saving economic and environment at working conditions of Qatar.

According to the Directorate General of EBTKE, Indonesia has a great deal of untapped potential for PLTS development because the equator passes through the country. Furthermore, the use of PLTS can mitigate the negative effects of carbon emissions caused by conventional power plants' reliance on coal. This research aims to quantify the savings in carbon emissions from PLTS deployment and to conduct an economic analysis of PLTS deployment by considering its Life Cycle Cost (LCC), Levelized Cost of Energy (LCoE), Net Present Value (NPV), and Payback Period (PBP). Profitability Index (PI) and Internal Rate of Return (IRR) for a pharmaceutical firm located in East Jakarta's PT Jakarta Industrial Estate Pulo Gadung. The results of the analysis that has been carried out obtain a total reduction in carbon emissions due to the use of PLTS when compared to JAMALI's electricity carbon emissions of 479.4 tons CO2eq in a year. The use of PLTS affects savings in paying electricity bills of IDR 591,145,354.06 each year and from the economic analysis using the methods (LCC, (LCoE), (NPV), (PBP), (IRR), and (PI) it is obtained that the feasibility The investment in PLTS development in this company is considered feasible.

There is an increasing need to perform real-time simulation of power plant performance behaviour using Hardware-in-the-loop (HiL) and/or Software-in-the-loop (SiL), particularly for HDVC grid connected wind power plants. Real-time simulation based on HiL/SiL can help mitigate grid connection challenges by allowing more realistic testing of the target system under different grid, weather and operational conditions, which is either impossible or costly to do on-site; hence, HVDC and wind power plants can be largely de-risked before connecting to the grid and start of operation. In this paper, the methods to develop source code based SiL models (same control code as in real products, such as Wind Turbine Generator) are investigated. Two main real-time simulation platforms are considered, i.e., RTDS and OPAL-RT. A common SiL execution platform based on IntervalZero is introduced, which can interface with both RTDS and OPAL-RT and thus, largely improve the interoperability and scalability of SiL models. In the end, a comparison between HiL and SiL models and between the SiL and PSCAD (offline) models are presented, including discussions about the intended use scenarios of real-time and offline simulation.

Techno-economic assessment of swine manure biochar production in large-scale piggeries in China

Two of the most important criteria are the net present value (NPV) and the internal rate of return (IRR) for choosing among investment projects. In many circumstances, investment projects are ranked in the same order by both criteria. In some situations, however, the two criteria provide different rankings. The debate is an old one (e.g. going back to Böhm-Bawerk, 1884). Let us explain the essence of the NPV and IRR indicators. The basis of economic calculations in the field of investment is the idea that a cash euro today is more valuable than a euro promised in a year. If a bank lends N euros to an entrepreneur today, then in a year the bank demands to return N(1 + E) euros, where E is the bank interest. Another type of calculation is carried out by the entrepreneur. If he invests N euros in some project today, then in a year he hopes to receive N(1 + IRR) euros, where IRR is the internal rate of return of the project implemented by the entrepreneur. Naturally, the value of IRR is only an assumed, indicative, and the entrepreneur is expecting IRR more than E. The present work arose from discussions of the results of the French economist Pierre Masse “Le Choix des investissements, critères et méthodes” published in 1959. The main goal of the paper is to give the proof of both IRR and NPV formulas (in a particular simplified case) and a geometric interpretation of these very complex equations (useful for the training purpose, at least). The analysis of IRR and NPV indicates an unequivocal choice among the criteria NPV and IRR. This confirms a simple numerical example on the fallacy of Masse’s IRR reasoning. No unambiguous solution has been found yet. It can be explained if we allow that the bank interest relates to Macroeconomics, largely concerned with nation scale projects but the entrepreneur interest relates to Microeconomics, to internal rate of return. The world continues to search for a single consistent criterion for evaluating investments.

Internal Rate Of Return Revisited