Capacity Of Power Plants Research Articles

Оценка технической возможности перевозки плодоовощной продукции морским транспортом между портами Каспийского моря

The modern process of fruit and vegetable transportation between countries depends not only on geographical, but also on political and economic factors, which makes for searching more efficient and shorter routes. The availability of such a transport opportunity as sea transportation between the ports of the Caspian Sea makes it possible to analyze new routes for the product transportation from Iran, Azerbaijan and other countries to Russia using dry cargo vessels that are currently used as the general cargo vessels. There have been analyzed the new routes for transportation of perishable products in refrigerated containers and assessed the possibility of their transportation on the “Volga” type bulk carriers. The routes “Astara (Azerbaijan) - Moscow”, “Astara - port Alat - port Kuryk - Moscow” have been illustrated. A general arrangement drawing of a “Volga” type dry cargo vessel (project 19610) is presented, the photographs of transporting timber and containers on the decks of dry cargo vessels are given. Calculating the load of the dry cargo ship’s power plant has shown a technical possibility of transporting 16 refrigerated containers on deck of the “Volga” type vessel without changes in the design of the ship’s power plant. Conclusions are made about the need to develop effective cargo transportation by waterways in modern conditions of the loss of traditional Russian suppliers of fruit and vegetable products, about the possibility of additional use of dry cargo ships, as well as the feasibility of developing a backup diesel generator for emergency power supply of deck refrigerated containers in connection with a possible increase in the capacity of the ship power plant.

Operation Strategy of Central Air Conditioning Virtual Power Plant Based on Risk Measurement Method

Virtual power plant is an integrated technology and operation mode to realize air-conditioning load participating in power system operation, further benefitting low carbon renewable energy applications. However, the principle of multi-system coupling in central air-conditioning poses a challenge to normal load regulation. Besides, the uncertainties of demand-side resources bring risks to the operation of virtual power plant. In this paper, the regulation characteristics of central air conditioning are obtained by experiment, while the potential of central air conditioning is quantified by a thermodynamic model, further resulting in the central air conditioning could be transformed into a virtual unit model. Then the dynamic capacity optimization strategy is formulated based on the risk measurement theory, while the generation task decomposition strategy is also formulated based on the equal increase rate criterion, thus forming a two-tier operation strategy of virtual power plant. Finally, illustrative case study is constructed to quantitatively analyze the power generation capacity and effectiveness of the virtual power plant. The effectiveness and practicability of the proposed strategy is also verified to benefit low carbon energy applications.

A Solution to Prevent a Blackout Crisis: Determining the Behavioral Potential and Capacity of Solar Power

Increasing the power grid peak in the summer time causes power outages in industries and residential areas in Iran. The most obvious example of this issue is the power outages in the summer of 2018. Management of the demand-side is the most important strategy to reduce the grid peak due to the high cost of the development of the power plant capacity (500$ per kilowatt). In the present study, the effect of behavioral parameters in decreasing the power grid peak was identified. The behavioral simulation was done as an agent-based model using the raw data of the time-use survey (TUS) of the Statistics Center of Iran. 4228 urban households were surveyed, and the quality of people’s behavior was determined in each time step of 15 minutes during the day and night with 2 deterministic and stochastic approaches. In the stochastic approach, the Markov chain method was used. It showed that the power grid peak can only be reduced by 10% with behavioral flexibility and up to 25% by upgrading technology. In addition, based on the power deficit in 2018, 2000 megawatts of solar power capacity must be added to the network at peak times to meet grid demand.

Five-Year Performance of an ESE Lightning Protection System for a Large Scale PV Power Plant in Thailand

This article presents a five-year performance review of an early streamer emission (ESE) air terminal lightning protection system for a large scale PV power plant in Thailand. The comparison effect of a Franklin lightning protection system and the ESE lightning protection system was analyzed for the PV power plant. The ESE lightning protection system was selected to be implemented in the PV power plant. The capacity of the PV power plant studied was 8 MWp on an area of 150,000 square meters in the Nong Ya Plong district, Phetchaburi province, Western Thailand. A Franklin lightning rod type was also designed to be implemented in this PV power plant. The Franklin lightning rod type comprised 122 pieces but the ESE lightning rod type consisted of only 11 pieces. The conceptual design of the Franklin rod type followed the standard of the Council of Engineers, Thailand, and the ESE lightning rod type followed the NFC17102 standard of France. The estimated cost of installation was a key comparison to select the lightning protection system; the total installation cost of the Franklin lightning rod type was USD 197,363.80 and the ESE lightning rod type was USD 44,338.06. The lightning system was applied to the lightning arrester in the power plant to provide good protection, in which the balance of the pole to the mounting position is required to optimize the system performance. The result of the simulation also showed that the shading effects of the Franklin rod type were greater than the ESE rod type. The installation cost of the Franklin lightning rod type was 4.45 times more expensive than the ESE lightning rod type. Therefore, the ESE lightning protection system was selected to be implemented in the PV power plant. From the recorded data of the five-year performance of the ESE lightning protection system (2016–2020), there were three occurrences of a lightning strike on the PV power plant. The ESE lightning protection system effectively protected and prevented the lightning strike to the PV power plant. This study can help and support with the selection of a lightning system for the protection of large scale PV power plants in the future.

Environmental Impact Assessment of Captive Power Plant Using LCA for Sustainable Development

The capacity of captive power plants has grown at a high rate in India in the recent past. As a result, harmful emissions have increased that need to be accounted for the overall sustainability of the parent plant. The aim of this research work is to quantify the environmental impact which is associated with the captive power plant usage through life cycle assessment approach. In the present study, Life cycle assessment (LCA) methodology is adopted from gate to grave system boundary. LCA of the CPP was conducted to assess the actual effect of power plant on the environment. The GaBi 6.4 software was used to analyze the energy input and emissions of harmful gases in the CPP. The study suggests that the Photochemical Ozone Creation Potential (POCP) created by the power plant is high and should be reduced.

A robust multiple-objective decision-making paradigm based on the water\u2013energy\u2013food security nexus under changing climate uncertainties

From the perspective of the water–energy–food (WEF) security nexus, sustainable water-related infrastructure may hinge on multi-dimensional decision-making, which is subject to some level of uncertainties imposed by internal or external sources such as climate change. It is important to note that the impact of this phenomenon is not solely limited to the changing behavior patterns of hydro-climatic variables since it can also affect the other pillars of the WEF nexus both directly and indirectly. Failing to address these issues can be costly, especially for those projects with long-lasting economic lifetimes such as hydropower systems. Ideally, a robust plan can tolerate these projected changes in climatic behavior and their associated impacts on other sectors, while maintaining an acceptable performance concerning environmental, socio-economic, and technical factors. This study, thus, aims to develop a robust multiple-objective decision-support framework to address these concerns. In principle, while this framework is sensitive to the uncertainties associated with the climate change projections, it can account for the intricacies that are commonly associated with the WEF security network. To demonstrate the applicability of this new framework, the Karkheh River basin in Iran was selected as a case study due to its critical role in ensuring water, energy, and food security of the region. In addition to the status quo, a series of climate change projections (i.e., RCP 2.6, RCP 4.5, and RCP 8.5) were integrated into the proposed decision support framework as well. Resultantly, the mega decision matrix for this problem was composed of 56 evaluation criteria and 27 feasible alternatives. A TOPSIS/Entropy method was used to select the most robust renovation plan for a hydropower system in the basin by creating a robust and objective weighting mechanism to quantify the role of each sector in the decision-making process. Accordingly, in this case, the energy, food, and environment sectors are objectively more involved in the decision-making process. The results revealed that the role of the social aspect is practically negligible. The results also unveiled that while increasing the power plant capacity or the plant factor would be, seemingly, in favor of the energy sector, if all relevant factors are to be considered, the overall performance of the system might resultantly become sub-optimal, jeopardizing the security of other aspects of the water–energy–food nexus.

Development of a Software System for Selecting Steam Power Plant to Convert Municipal Solid Waste to Energy

A software system that enhances the selection of appropriate power plant capacity that will convert combustible municipal solid waste (MSW) into energy was developed. The aggregate of waste to be converted was determined and the corresponding heating value was established. The capacities of steam power plants’ components required for the conversion were determined, using thermodynamic mathematical models. An algorithm based on models used to determine the energy potential, the power potential of MSW, the capacities of the components of the steam power plant, were translated into computer soft code using Java programming language; saturated steam and superheated steam tables, together with the thermodynamic properties of the power plant required were incorporated into the soft code. About 584 tons of MSW having a heating value of 20 MJ/kg was the quantity of waste experimented for energy generation. This information was input into the software as data and was processed. Then, the software was able to predict 3245.54 MWh energy potential for the quantity of waste, and electrical power potential of 40.54 MW. The capacities of the steam power plant components that were predicted include 100.35 MW of boiler power, 40.54 MW of turbine power, and 59.80 MW of condenser power. The methodology adopted will make it easy for the managers in the waste-to-energy sector to appropriately select the suitable capacity of the required steam power plant that can convert any quantify of MSW at any geographical location, without going through the engineering calculation and stress or rigor involved in the plant capacity design. Moreover, the accuracy obtained for the software is greater than 99%.

Optimal Placement of Wind Power Plants in Transmission Power Networks by Applying an Effectively Proposed Metaheuristic Algorithm

In this paper, a modified equilibrium algorithm (MEA) is proposed for optimally determining the position and capacity of wind power plants added in a transmission power network with 30 nodes and effectively selecting operation parameters for other electric components of the network. Two single objectives are separately optimized, including generation cost and active power loss for the case of placing one wind power plant (WPP) and two wind power plants (WPPs) at predetermined nodes and unknown nodes. In addition to the proposed MEA, the conventional equilibrium algorithm (CEA), heap-based optimizer (HBO), forensic-based investigation (FBI), and modified social group optimization (MSGO) are also implemented for the cases. Result comparisons indicate that the generation cost and power loss can be reduced effectively, thanks to the suitable location selection and appropriate power determination for WPPs. In addition, the generation cost and loss of the proposed MEA are also less than those from other compared methods. Thus, it is recommended that WPPs should be placed in power systems to reduce cost and loss, and MEA is a powerful method for the placement of wind power plants in power systems.

Seismic capacity re-evaluation of the 480V motor control center of South Korea NPPs using earthquake experience and experiment data

The recent seismic events that occurred in South Korea have increased the interest in the re-evaluation of the seismic capacity of nuclear power plant (NPP) equipment, which is often conservatively estimated. To date, various approaches—including the Bayesian method proposed by the United States (US) Electric Power Research Institute —have been developed to quantify the seismic capacity of NPP equipment. Among these, the Bayesian approach has advantages in accounting for both prior knowledge and new information to update the probabilistic distribution of seismic capacity. However, data availability and region-specific issues exist in applying this Bayesian approach to Korean NPP equipment. Therefore, this paper proposes to construct an earthquake experience database by combining available earthquake records at Korean NPP sites and the general location of equipment within NPPs. Also, for the better representation of the seismic demand of Korean earthquake datasets, which have distinct seismic characteristics from those of the US at a high-frequency range, a broadband frequency range optimization is suggested. The proposed data construction and seismic demand optimization method for seismic capacity re-evaluation are demonstrated and tested on a 480 V motor control center of a South Korea NPP.

Efficient use of heat from CHP distributed by district heating system in district cooling networks

District cooling (DC) can play an important role in smart energy systems. With the global trend of reducing heat loss in buildings, cooling demand will continue to increase. Considering the potential for free cooling and waste heat utilisation in DC systems, a practical approach is needed to develop new DC networks. Tallinn has over 60 years of experience in developing district heating (DH) networks. The city has installed large capacities of biomass-based combined heat and power plants (CHPs). National support mechanisms allow the DH operator to generate power from CHPs and reject heat during warmer months when the heat load is insufficient. This heat can be used for DC. This study investigates an applied approach to DC development in Tallinn’s Ülemiste City. Ülemiste City is a business park with an existing developed area of 160 000 m 2 . The main source of cooling for the DC network is an absorption chiller that uses rejected heat from a CHP 7 kilometres away from the DC plant. The current DH supply temperature in Tallinn during the non-heating season is 70 °C. To determine the optimal technical solution for an effective energy efficiency ratio of the absorption chiller and heat transmission in the DH network, various scenarios were evaluated where the DH supply temperature was 70 °C, 80 °C, and 90 °C. An assessment of the technical parameters is provided for these scenarios. The paper presents an overview of the efficient use of rejected heat from CHPs in DC.

A study on carbon cap and trade effect to cost of electricity in accordance with the Merit Order of 300-400 MW coal power plants

Electricity is the basis of national development in a country. Power plants in Indonesia produces up to 283.8 TWh and are dominated by coal power plants which increase the amount of the greenhouse gases (GHG). In order to prevent more environmental problems, Indonesia ratified Paris Agreement by publishing the roadmap of Nationally Determined Contribution (NDC) that committed in reducing 29% of GHG emissions in 2030, which 11% of them are from the energy sector contributions. This research focuses on the implementation of the carbon cap and trade (CAT) between coal power plants having 300-400 MW capacity, which can affect their cost of electricity (Rp/kWh). It is well known that cap and trade (CAT) is a method used for reducing the mitigation cost of emission reduction in an effective way. From this research, it is found that the highest rise of incremental cost belongs to the 300 MW power plant in scenario 9 and the increase is from Rp.431.00/kWh to Rp.462.77/kWh, or approximately 7.37%. This research also shows that the most optimal carbon price is in the range of Rp. 130,165 to Rp.130,183 because the rank of the 330 MW and 400 MW power plant in merit order changes over in this condition. In the future, this research can be used as a comparison with the higher coal power plant capacity, so that an alternative way is obtained to determine the more optimal merit order.

Least-Cost Non-RES Thermal Power Plants Mix in Power Systems with Majority Penetrations of Renewable Energy

The ambitious targets of the European Union (EU) for a greater penetration of renewable energy sources (RES) in all areas of activity have led to power systems with growing levels of variable RES (VRES) all over the EU. Considering these targets, the EU countries presented their National Energy and Climate Plans (NECP) with their expected capacity until 2030. The NECPs considered a relevant increase in the VRES capacity and in some cases a decrease in the capacity of dispatchable power plants. VRES have near-zero marginal costs and increase the volatility of the net-load due to the stochastic profile of their production. These characteristics increase the need to maintain fast-response dispatchable power plants to guarantee the security of supply and also decrease market prices. Thus, governments promote externalities, as capacity mechanisms and other incentives to these players, guaranteeing their economic sustainability. This study presents the optimization of the non-RES thermal capacity of the Iberian power system by 2030, considering the least-cost algorithm. Considering a cooperative scenario between Portugal and Spain, it is possible to reduce the system costs by 17.40%, the curtailments quantity by 21.93%, the number of market-splitting hours by 43.26% and the dioxide carbon emissions by 4.76%.

Thermal energy storage with phase change materials in solar power plants. Economic analysis

Thermal energy storage (TES) increases concentrating solar power (CSP) plant capacity factors, but more important, improves dispatchability; therefore, reducing the capital cost of TES systems is very important to reduce cost of energy and serve as an enabler for commercial solar power plants. After presenting the concept of a novel cascade PCM configuration of CSP and demonstrating it energy efficiency, it is needed to develop a thoughtful economic evaluation of the concept. The goal of this paper was to investigate this system through annual modelling, engineering procurement company price quotes, and levelized cost metric comparison with a baseline case, the commercial two-tank molten salt storage system. Simulation results show that this new PCM concept decrease levelized costs of storage. The baseline of using shell and tube heat exchangers for PCM storage offers a reduction in capital and levelized cost, but this paper also shows that there are further cost reduction possibilities, as shown in the scenarios presented here, such as thermal conductivity enhancement, encapsulation of the PCM, or modification of the material to improve its thermal properties. Therefore, although the basic shell and tube PCM system has been shown to offer a cost savings, the 1.8% reduction in LCOE may not be worth the risk of further development. The shell and tube system should be a jumping off point to more appropriate technologies. The variants studied are likely to yield cost reductions in cost performance quotient (CPQ) as high at 80% and in LCOE as high as 10%, representing an unprecedented and valuable avenue of CSP plant cost reduction.

A performance evaluation of an integrated solar combined cycle power plant with solar tower in Saudi Arabia

• A 548.4 MW Integrated solar combined cycle power plant is proposed including 50 MW from solar tower technology. • A techno-economic analysis outcomes are incorporated with the weather characteristics of Saudi Arabia. • On-the-ground measured meteorological data is adopted for accurate simulations. • The hybridized solar tower field achieved efficiency ranging between 53 and 59% annually and a capacity factor of 49.9%. • The annual generation of the solar tower field is found to be at 220.89 GWh and the levelized cost of energy 12.71 cent/kWh. Improving the diversification and sustainability of Saudi Arabia’s national electricity grid is a strategic priority. In order for this objective to come to fruition, increasing the penetration of renewable energy resources (RESs) is of paramount importance. This is where the importance of improving solar powered technologies becomes crucial. Specifically, concentrated solar thermal power (CSP) technologies have significant potential in Saudi Arabia, as well as other locations with high averages of direct normal irradiation. In this research, a techno-economic analysis has been conducted for the adoption of an integrated solar combined cycle (ISCC) which utilizes solar tower (ST) technology in Saudi Arabia. The power plant under study has a total capacity of 548.4 MW, of which 50 MW is from CSP. The outputs of this model are compared with other conventional and renewable energy sources quantitively. The results show that the hybridized ST field can achieve efficiency ranging between 53 and 59% annually leading to a capacity factor of 49.9% which is higher than other RES technologies of similar intermittent nature. The solar field installed capacity represents 9.11% of the total power plant capacity, whereas its output represents up to 10.7% of the total output. The annual generation of the solar tower field is found to be at 220.89 GWh, net present value (NPV) 10.2 MSUD, and levelized cost of energy (LCOE) 12.71 cent/kWh. The results reflect that the hybridization of CSP with conventional combined cycle gas turbine (CCGT) results in enhanced annual generation, lower energy cost, and facilitates the transition to stand-alone CSP. The hybridization of ST ISCC helps to steadily build up the know-how of the operation and maintenance of a technology with great potential given the weather and demand characteristics of Saudi Arabia. Results of this research can facilitate decision-making in the early stages of penetrating CSP to the electricity mix in the Saudi national grid in order to achieve the desired sustainability of energy sources.

Energy, exergy and exergy-economic analysis of a new multigeneration system based on double-flash geothermal power plant and solar power tower

In this research, a multigeneration system consisting of a double-flash geothermal power plant, solar power tower, organic Rankine cycle, alkaline electrolyzer and a single-stage absorption chiller is presented. In this research, the solar power tower has been used to improve the performance of the double-flash geothermal power plant. Combining such a Concentrated solar power system with a double-flash geothermal power plant was not previously addressed. Also, to increase the whole system's efficiency, the waste heat from the double-flash geothermal power plant and the solar power tower in the proposed system have been used. The proposed system is capable of producing power, hydrogen, heating, and cooling. The multigeneration system has been analyzed by EES software for energy, exergy, and exergy-economy. To study the impact of important parameters on system performance, it has been analyzed parametrically in different conditions. The proposed system is capable of generating 43,640 kW of electricity, 161,604 kgh of hydrogen, cooling of 1243 kW and hot water consumption of 8870 kW in full use of the geothermal source. In the present research, in order to improve the lifetime of the geothermal well, the flow rate of geothermal fluid entering the system is reduced to reach the production capacity of the reference geothermal power plant to achieve the same amount of electricity generation as the base system by the proposed multigeneration system. In this case, 21% less geothermal fluid is extracted from the geothermal source. Under these conditions, the multigeneration system has Energy and Exergy efficiency of 19% and 19.29%, respectively, and the cost of electricity and H2production is equal to 0.1477 $kWhand 7.626 $kg.

GEOSPATIAL ASSESSMENT FOR PLANNING A SMART ENERGY CITY USING ROOFTOP SOLAR PHOTOVOLTAIC IN BANDUNG CITY, INDONESIA

Abstract. Increasing the production of clean and environmentally friendly energy has become one of the world agendas as a strategic effort in dealing with long-term climate change. Seeing the potential of the energy produced, the ease in the installation process, with the small risk of harm generated, solar energy has received significant attention from many countries in the world. The potential for solar energy in Indonesia alone reaches 207 GWp, but only 145.81 MWp has been utilized. Currently, the Indonesian government has set a target to build a Solar Power Plant capacity in 2025 of 6.5 GWh. Urban areas are areas with higher energy demand than rural areas, but the availability of vacant land in urban areas is very minimal for installing solar power plants. Therefore, rooftop solar PV(Photovoltaic) can be a solution in dense areas such as cities. Good planning by looking at the potential resources and energy needs in spatial is needed to manage and utilize energy optimally and sustainably in urban areas. This study aims to develop a geospatial assessment for plan smart energy city that uses rooftop solar PV's potential energy in every building that is effective and efficient. The novelty in the analysis of the distribution of the potential for rooftop solar PV development in urban areas integrates meteorological and spatial aspects and socio-economic aspects. Integration of multi-dynamic spatial data uses in determining the rooftop solar PV construction location, such as meteorological data for solar energy potential, increasing energy needs of each building, and socio-economy data. The data source used comes from statistical data and remote sensing data. The analysis will be carried out temporally (2008, 2013, and 2018) to see the pattern of changes in aspects used in a certain period so that the development plan can be carried out more optimally. This research's output is the formation of a priority analysis of solar PV rooftop construction in urban areas, especially the city of Bandung. The result of energy can also produce by the construction of rooftop solar PV in a potential area. This research is expected to be utilized by policymakers to develop renewable energy in the city of Bandung and increase community participation in switching to renewable energy.

Listrik Tenaga Surya untuk Pompa Submersible pada Greenhouse Hidroganik di Kabupaten Malang

This service activity is the application of an innovative submersible solar pump in a hydro-organic greenhouse environment in Grangsil Jambangan, Malang Regency. This is motivated by the need for water that can only be obtained through deep wells with submersible pumps in hydro-organic greenhouses that already use solar power plants but have insufficient power. The purpose of this service is to provide theoretical and practical understanding for Tour conscious group (POKDARWIS) Jambangan members as managers of the hydro-organic greenhouse. The methods used include focus group discussions (FGD) and joint practice in developing solar power plants for submersible pumps. After the implementation of this program, there was an increase in the capacity of the solar power plants, which has been able to turn on submersible pumps, hydroganic circulation pumps, and other needs. In one day, the submersible pump only needs to be turned on for 2 hours and produces 4,572 liters of water, sufficient for greenhouse hydroganic needs and other needs. Another positive impact is that POKDARWIS Jambangan members have been able to manage and maintain PLTS for a hydro-organic greenhouse. The submersible water pump prototype for hydroganic agriculture at the greenhouse using independent energy is very practical and efficient so it is expected to become a prototype for modern agricultural facilities in the context of a national-scale food security improvement program.

Evaluation of Heat Production from Single Fracture Hot Dry Rock with Applications for EGS Reservoir Design

Enhanced Geothermal Systems (EGS) are the most effective methods for extracting geothermal energy from deep hot dry rock (HDR). The EGS reservoir framework is envisioned as independent-multiple fractures connecting injection and production wells. The reservoir is further conceptually represented by a single fracture with homogeneous features, and a unit fracture is defined as having extendibility to a larger surface area for heat extraction. An analytical solution for the thermal-hydraulic coupling process is derived with a 1-D steady state conductive heat flow in the HDR with perpendicular water flow in the single fracture and transient heat transfer from rock to water. The heat produced from the HDR via water flow in the idealized single fracture is demonstrated by arithmetic equations. The lifetime of an EGS reservoir in these reference conditions is 23.2 years and is confined by the produced water temperature of 150°C for commercial utilization. The heat recovery factor is 12.4%. With a power plant capacity of 5 Mw installed, the total area for extracting recoverable heat within the projected lifetime of a fracture surface of 1.58×106m2was determined. The discussion shows the ability of the model to estimate heat production and reservoir scale.

BALANSING OF POWER AND ELECTRICITY IN THE ELECTRIC POWER SYSTEM WITH RENEWABLE ENERGY SOURCES BY CRITERIONAL METHOD

This article considers the features of the development of renewable energy sources in electrical networks. The main changes in the functional properties of power systems, which include a significant reduction in electricity consumption, change in the structure of electricity consumption, rapid increase in the installed capacity of solar and wind power plants. Electricity consumption in 2020 is almost halved compared to 1990 (from 227 to 119 billion kWh) and as a consequence the share of semi-peak thermal generation, which gave the power system basic flexibility, has significantly decreased (from 71 % in 1990 to 35 % in 2020) and at the same time the share of nuclear generation, which operates in base mode, has increased (from 25 % to 51 %). In particular, consumption by industry with a stable load schedule, decreased (from 146 billion kWh (64 %) to 49 billion kWh (42 %)). At the same time, the demand for electricity by the households, whose consumption profile of which is characterized by significant daily unevenness and sensitivity to meteorological factors, has significantly increased (from 21 billion kWh (9 %) to 37 billion kWh (31 %)). Therefore, the article analyses the preconditions for the problem of flexible generation and explores possible ways to solve them. The optimal composition of electricity generation for Ukraine in the period 2021–2025 is proposed, which provides for the preservation and even increase by optimizing the repair campaign of the share of electricity production by nuclear power plants, the introduction of additional 2–2.5 GW of highly flexible generation and up to 2 GW storage systems (taking into account the pumped-storage power plant), as well as a gradual evolutionary decline in both installed capacity and electricity production by semi-peak coal-fired power plants and maintaining a policy of decarbonisation to ensure its own energy security. A comprehensive approach to compensating for the instability of renewable energy sources generation has been developed, which consists in minimizing the cost of power redundancy in various available ways. The problem of cost optimization for ways to compensate for the instability of renewable energy sources generation is solved by the method of criterion programming. The impact of each backup method on total costs is determined using sensitivity theory.

ENSURING PERMISSIBLE VOLTAGE LEVELS IN LOW-VOLTAGE NETWORKS IN THE DESIGN OF SOLAR POWER PLANTS FOR PRIVATE HOUSEHOLDS

One way to stimulate the development of renewable energy is preferential electricity tariffs for businesses, electricity consumers, including energy cooperatives and private households, whose generators produce electricity from alternative energy sources. Such a state policy exists both in Ukraine (the "green tariff") and in other countries (Feed-in tariffs). The simplified connection mechanism of generating power of private households and the fast payback period of solar power plants have led to a rapid increase in the number of such facilities. The peculiarity of network photovoltaic installations of private households is that the investment is proportional, and sometimes even less than the cost of additional reconstruction, for example, to increase the capacity of the electrical network, so, as a rule, their connection to low voltage networks is carried out without any additional changes of intersections of power lines. At the same time, according to the Law of Ukraine on the Electricity Market, the connection of generating installations to consumers, including private households, should not lead to deterioration of regulatory parameters of electricity quality. Another feature of these objects is the almost complete lack of information about the parameters of the electrical network. In the absence of reliable information, it becomes necessary to develop approximate methods for estimating the allowable capacity of solar power plants of private households depending on the place of connection, the parameters of the modern low-quality distribution network and modes of its operation. The article proposes the use of the distribution network model in the form of a line with evenly distributed load from the solar power plants in the form of a concentrated load at the corresponding point of the line. The voltage distribution along the line is simulated when the power of the solar power plant and the place of its connection change. Analytical relations are obtained for the calculation of the solar power plants power limit values to ensure the admissibility of the mode parameters according to the voltage level when varying the solar power plant connection point. A method is proposed to maintain the allowable minimum voltage levels at the terminals of consumers in short-term congested sections of the network.