scholarly journals Probabilistic Energy Flow Calculation through the Nataf Transformation and Point Estimation

2019 ◽  
Vol 9 (16) ◽  
pp. 3291 ◽  
Author(s):  
Qin ◽  
Fang ◽  
Ma ◽  
Li

With the increasing capacity of renewable energy sources, uncertainties regarding renewable energy and other dynamic loads in integrated energy systems (IESs) are increasing. Thus, it is necessary to study the probabilistic energy flow (PEF) of IESs. However, existing PEF calculation methods such as the point estimate method (PEM) are computationally inefficient when there are many random variables and estimated points; moreover, relatively large errors can occur when the estimated points are outside their limits. Hence, this paper presents a calculation method that addresses these problems. Because there are correlations among the variables, the Nataf transformation is employed to control the correlation quickly and effectively. A model for an IES that is interconnected with natural gas and electricity systems and accounts for the uncertainties of wind plants, photovoltaic power plants, and dynamic gas loads is presented. Correlations between wind plants and photovoltaic power plants are handled using the Nataf transformation. Finally, a modified PEM is developed to solve the PEF. For situations in which the estimated points exceed their boundaries, the power transformation and equal constraint transformation methods are used. The results of time-domain simulations demonstrate the effectiveness of the proposed approach.

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Aleksandra Kanevče ◽  
Igor Tomovski ◽  
Ljubčo Kocarev

In this paper we analyze the impact of the renewable energy sources on the overall electric power system of the Republic of Macedonia. Specifically, the effect of the photovoltaic power plants is examined. For this purpose we developed an electricity production optimization model, based on standard network flow model. The renewable energy sources are included in the model of Macedonia based on hourly meteorological data. Electricity producers that exist in 2012 are included in the base scenario. Two more characteristic years are analyzed, i.e. 2015 and 2020. The electricity producers planned to be constructed in these two years (which include the renewable energy sources) are also included. The results show that the renewable energy sources introduce imbalance in the system when the minimum electricity production is higher than the electricity required by the consumers. But, in these critical situations the production from photovoltaic energy sources is zero, which means that they produce electricity during the peak load, and do not produce when the consumption is at minimum.


2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Milko Yovchev ◽  
Plamen Tsankov

The paper presents technical and economic data on the development of photovoltaic electricity in Bulgaria over the last 10 years. The mix of different types of conventional and renewable energy sources in the country's electricity system is shown. The changes in the installed photovoltaic capacities and the price of electricity generated by them for the studied period are shown in tabular and graphical form. The number of photovoltaic power plants and their distribution by groups of individual powers are given. Brief technical and economic data for some of the largest photovoltaic power plants in Bulgaria are provided. Data analysis shows a short period of rapid development of highcapacity photovoltaic power plants construction after the introduction of high feed-in tariff for the purchase of photovoltaic electricity, as well as the influence of the installed photovoltaic capacities on the market change of the feed-in tariff over time. Feed-in tariff cost decreases remarkably with the increase of the installed photovoltaic capacity and even shows removal tendency for larger-capacity photovoltaic power plants. Examples of the economic profitability of grid-connected and autonomous photovoltaic systems in Bulgaria are given. The analysis and conclusions of the paper could be useful in determining new government policies and setting new market conditions to promote the development of renewable energy sources in Bulgaria and other countries.


2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Aleksandra Dedinec ◽  
Igor Tomovski ◽  
Ljupčo Kocarev

This paper is motivated by a large tendency of shift towards low emission electricity production, which can be achieved by substituting the conventional energy sources by renewable energy sources. Therefore, a share of renewable energy sources is continually growing. However, large-scale integration of renewable energy sources into the power system is a challenging task, since it depends on a balance between demand and supply at any time and because of the nature of renewable energy sources. The production from some sources such as the photovoltaic and wind power plants fluctuates depending on meteorological conditions, so it cannot be regulated. However, large hydropower plants can be regulated, so they are suitable for electricity balancing. In this paper, an optimization model is set for a system with 100 % renewable energy sources, which includes models for correlation of meteorological data and the production of electricity from different variable renewable energy sources. The resulting model gives an optimal ratio of production of variable renewable energy sources, which depends on the share of these sources in the total electricity production. The objective function of this optimization problem is to minimize the excess and lack of electricity production. For this purpose, hourly data for electricity consumption and hourly meteorological data are included. The results show that if only wind and photovoltaic power plants are considered, for the case of Macedonia, this optimum is found at 72% wind and 28% photovoltaic power production. However, if the already installed capacity of the big hydropower plants and the maximal potential of the small hydropower plants which make together 30% of the total installed capacity is taken into account, the optimal ratio of production from the other sources is: 50% wind power generation and 20% photovoltaic power generation.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3860
Author(s):  
Priyanka Shinde ◽  
Ioannis Boukas ◽  
David Radu ◽  
Miguel Manuel de Manuel de Villena ◽  
Mikael Amelin

In recent years, the vast penetration of renewable energy sources has introduced a large degree of uncertainty into the power system, thus leading to increased trading activity in the continuous intra-day electricity market. In this paper, we propose an agent-based modeling framework to analyze the behavior and the interactions between renewable energy sources, consumers and thermal power plants in the European Continuous Intra-day (CID) market. Additionally, we propose a novel adaptive trading strategy that can be used by the agents that participate in CID market. The agents learn how to adapt their behavior according to the arrival of new information and how to react to changing market conditions by updating their willingness to trade. A comparative analysis was performed to study the behavior of agents when they adopt the proposed strategy as opposed to other benchmark strategies. The effects of unexpected outages and information asymmetry on the market evolution and the market liquidity were also investigated.


Author(s):  
Seyedeh Asra Ahmadi ◽  
Seyed Mojtaba Mirlohi ◽  
Mohammad Hossein Ahmadi ◽  
Majid Ameri

Abstract Lack of investment in the electricity sector has created a huge bottleneck in the continuous flow of energy in the market, and this will create many problems for the sustainable growth and development of modern society. The main reason for this lack of investment is the investment risk in the electricity sector. One way to reduce portfolio risk is to diversify it. This study applies the concept of portfolio optimization to demonstrate the potential for greater use of renewable energy, which reduces the risk of investing in the electricity sector. Besides, it shows that investing in renewable energies can offset the risk associated with the total input costs. These costs stem from the volatility of associated prices, including fossil fuel, capital costs, maintenance, operation and environmental costs. This case study shows that Iran can theoretically supply ~33% of its electricity demand from renewable energy sources compared to its current 15% share. This case study confirms this finding and predicts that Iran, while reducing the risk of investing in electricity supply, can achieve a renewable energy supply of ~9% with an average increase in supply costs. Sensitivity analysis further shows that with a 10% change in input cost factors, the percentage of renewable energy supply is only partially affected, but basket costs change according to the scenario of 5–32%. Finally, suggestions are made that minimize risk rather than cost, which will bring about an increase in renewable energy supply.


Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by: 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are: 1) thermal - primary coal and secondary natural gas; 2) “large” hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that they are still the largest emitters of carbon dioxide into atmosphere. Due to that, reliable non-fossil-fuel energy generation, such as nuclear power, becomes more and more attractive. However, current Nuclear Power Plants (NPPs) are way behind by thermal efficiency (30–42%) compared to that of advanced thermal power plants. Therefore, it is important to consider various ways to enhance thermal efficiency of NPPs. The paper presents comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.


2021 ◽  
Vol 12 (3) ◽  
pp. 631
Author(s):  
Sergey BESPALYY

The growth of renewable energy sources (RES) shows the desire of the government of Kazakhstan to meet challenges that affect the welfare and development of the state. National targets, government programs, policies influence renewable energy strategies. In the future, renewable energy technologies will act as sources of a green economy and sustainable economic growth. The state policy in the field of energy in Kazakhstan is aimed at improving the conditions for the development and support of renewable energy sources, amendments are being made to provide for the holding of auctions for new RES projects, which replaces the previously existing system of fixed tariffs. It is expected that the costs of traditional power plants for the purchase of renewable energy will skyrocket, provided that the goals in the field of renewable generation are achieved. This article provides an assessment of international experience in supporting renewable energy sources, as well as analyzes the current situation in the development of renewable energy in Kazakhstan and the impact on sustainable development and popularization of the «green» economy. The study shows that by supporting the development of renewable energy sources, economic growth is possible, which is achieved in an environmentally sustainable way.


2019 ◽  
Vol 1 (1) ◽  
pp. 14
Author(s):  
Rizal Akbarudin Rahman ◽  
Aripriharta Aripriharta ◽  
Hari Putranto

The use of renewable energy as a source of electrical energyincreases every year. Unfortunately, Indonesia does not have manypower plants that utilize renewable energy sources. The mostpotential renewable energy in Indonesia is the sunlight with the helpof solar panels that converts solar energy into electrical energy.However, the environment could affect the solar panel module andin turn, affect the performance of solar panels or the generatedelectric energy. This research calculated the performance of solarpanels with a single-diode model using the Five Parameters methodthat required solar panel module specification data, the totalradiation absorbed by the solar panel module, and the temperatureof the environment. The Five Parameters method is a methodmodeled after solar panel module performance in the form of thesingle-diode equivalent circuit. The Five Parameters method isreliable in predicting the energy produced by the solar panels whenthe input data is limited. The results for using the Five Parametersin monocrystalline solar panels were Isc = 1.827 A, Imp = 0.662 A,Voc = 18.221 V, Vmp = 15.019 V, Pmp = 9.955 W. And the results inpolycrystalline solar panels were Isc = 1.926 A, Imp = 0.686 A, Voc =17.594 V, Vmp = 14.166 V, Pmp = 9.722 W. Based on the results; itwas concluded that the most efficient and optimised types of solarpanels on natural conditions in Sendang Biru Beach was themonocrystalline solar panel because it produced electrical outputpower of 9.955 W. Therefore, there could be a manufacturer ofsolar energy power plants to reduce the cost of electricity in thecoastal area, such as in Sendang Biru Beach.


Author(s):  
V. V. Shevchenko ◽  
A. N. Minko ◽  
M. Dimov

The paper defines the directions of improving turbogenerators as the basis for ensuring the energy independence of Ukraine. The analysis of the state, problems and prospects for the development of modern electric power industry. Goal of the work is to identify promising directions for sustainable development of the national electric power industry in order to ensure energy security of Ukraine, to conduct a comparative analysis of electricity sources, to confirm the need to improve the main sources – turbogenerators. Methodology. During the research, an analytical analysis of the electricity sources, which are installed at power plants in Ukraine and the world, was carried out, taking into account the growth of the planet's population and its energy activity. Cyclic theory was chosen as the theoretical basis for forecasting. On the basis of this theory, global development trends, advantages and disadvantages of currently used sources of electricity - thermal (including nuclear) power plants and stations that operate from renewable energy sources - have been established. A review of literary sources on the methods of the energy sector forecasting the development, including the development of the energy sector in Ukraine, has been carried out. Originality. It has been established that due to the active growth of the planet's population, with the increase in its energy activity, obtaining electricity from renewable energy sources is not enough, that for the next 20-30 years nuclear power plants will be the main sources of electricity. The internal and external threats to the energy security of Ukraine, directions of development of turbogenerator construction, ways to improve turbogenerators, to increase their energy efficiency, power per unit of performance, to increase the readiness and maneuverability factors, and overload capacity have been identified. Practical significance. The need to continue the modernization and improvement of the turbogenerators of nuclear power plant units, as the main sources of electricity, has been proved. The directions of their improvement are established: increasing the power in the established sizes, making changes to the design of the turbogenerators inactive elements, replacing the cooling agent to keep Ukrainian turbogenerators at the world level, improving auxiliary systems, improving and increasing the reliability of the excitation system, introduction of automatic systems for monitoring the state turbogenerators. Possible limits of use, advantages, disadvantages and problems of using renewable energy sources for Ukraine have been established.


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