System Operation Cost Research Articles

신재생융복합시스템이 적용된 시설원예의 온실가스 및 운영비용 절감 효과 분석

In this study, the empirical data of a heating season of renewable energy convergence system installed at the Purme farm in Yeoju, Gyeonggi-do was analyzed. Through comparative comparison with other heat sources such as oil and electricity, which are widely used in conventional greenhouses, the operation cost and greenhouse gas reduction effect of the proposed system were analyzed. The proposed renewable energy convergence system consisted of solar collectors, seasonal thermal energy storages, hybrid source heat pumps, and ground source heat pumps. The heat generated from the proposed system was stored in the thermal energy storage and supplied to the greenhouse. From October 2021 to March 2022, about 38.4% of the total 481.9 MWh of heating heat at the farm was supplied directly or indirectly through the solar system. In addition, the system COP of the heat pump system was determined as 2.28, and the system COP of the entire proposed system was 2.40. Both the operation cost and greenhouse gas emission of the proposed system were lower than the conventional systems.

Optimization of Multi-microgrid System Operation Cost with Different Energy Management Tools in the Presence of Energy Storage System

— Given the increasing capacity of distributed generation and renewable resources, how to use this capacity and proper energy management will be a major challenge for low-capacity networks such as microgrids. With the help of peripherals tools, an arrangement can be made to achieve a more desirable result in the energy management system (EMS). Storage resources and at a higher level, the storage module is used as one of these tools in the subsystems of the EMS. In this article, in addition to taking advantage of the connection of several microgrids to each other and reducing interactions with the main network, by using the storage module and other related tools, the cost of providing energy to a cluster of microgrids is reduced to the lowest possible value. By implementing a mathematical model based on mixed-integer linear programming, the best program for generation resources obtains in such a way that the cost of energy supply reduces to the minimum value. The study results have been analyzed in two case studies; a modified laboratory microgrid and the IEEE 33-bus distribution network. Although different solvers in Gams will provide almost similar answers, the optimal answer was found by the Cplex solver.

A hybrid constrained Particle Swarm Optimization-Model Predictive Control (CPSO-MPC) algorithm for storage energy management optimization problem in micro-grid

This paper investigates energy management systems in micro-grid using an optimization-based approach, optimizing the operating cost related to the energy purchased from the utility grid, the operation cost of the energy storage system, and revenue from the selling of energy to the utility grid. This research uses a constrained Particle Swarm Optimization-Based Model Predictive Control (CPSO-MPC) and a Linear Program-Based Optimization approach to solve the constrained optimization problem formulated in micro-grid energy management. Due to the absence of constraint management strategies in the traditional PSO algorithm, it is incapable of solving constrained optimization problems. Hence, to overcome this drawback, an intuitive approach known as Deb’s rule is applied to handle the constraints. The simulation results show the modified particle swarm optimization’s effective performance embedded in the model predictive control algorithm compared to the linear programming algorithm.

Marginal utility of battery energy storage capacity for power system economic dispatch

The battery energy storage (BES) is recognized as a key resource for the power fluctuations smoothing, peak load shaving and frequency regulation, and its performance depends heavily on the available capacity. It is meaningful to investigate the influence of the BES capacity on the power system operation cost. This paper focuses on the marginal utility of BES capacity in the day-ahead power system operation cost. Firstly, the day-ahead economic dispatch problem is formulated as a constrained quadratic programming problem, with the consideration of the BES degradation cost. Then, the relationship between the BES-related shadow prices and the marginal electricity price is derived from the KKT conditions of the dispatch problem. Based on it, the marginal utility of BES capacity is modeled to evaluate the effect of BES capacity on the system day-ahead operation cost. Finally, the numerical results demonstrate that the proposed marginal utility can manifest the influence of BSS capacity on the power system operation.

Air-rocket space launch system - as Responsive Space System

ObjectivesThe study was to analyze the concept of Responsive Space Systems alternative launch and set of the nanomicro satellites into Low Earth Orbit. The analysis focused on aircraft-rocket space systems, where platform for launching a rocket with a satellite is an aircraft.The aircraft in the role of the platform provides opportunities, system thus the operator doesn't need bases or space ports in European conditions.MethodsAnalysis of the research area, focused on the review, critical analysis, evaluation of the available literature, resources. The work was supplemented with the results and recommendation of the research project recently carried out at the MUT.ResultsSystems were presented in view of the war in Ukraine. Existing operational and currently designed systems were reviewed. Article evaluated the aerial-rocket systems for launching objects into the LEO in the context of the system's operational costs and capabilities, potential market and further military and civilian applications also the needs of the Polish Armed Forces. Combat aircraft and rocket kits based on decommissioned from PAF fighters were proposed and valuated.ConclusionsImplementation of system gives autonomy from countries or companies offering space services, possibility of mastering new capabilities of placing satellite systems for security&defense purposes. For the PAF, aircraft-rocket kits based on phased-out supersonic combat aircraft may be the start of the development and construction of the national Responsive Space System. The country's scientific-industrial base has competence to design&build such a system. Polish Space Agency can act as an integrator of the system just as NASA did in the 1960s.

Optimal design for improving operation performance of electric construction machinery collaborative system: Method and application

Electrification of construction machinery is an important measure to reduce carbon emissions from the transportation industry, and collaborative work is an essential feature of construction machinery. Current research on vehicle mechanical component optimization lacks consideration of the collaborative system's overall performance and a unified standard for optimizing component selection. So, it is uncertain to optimize single-machine components to improve system performance. This paper proposes an optimization design method for collaborative system. Firstly, based on the meta-action theory and analytic hierarchy process, the meta-action unit of the optimal design is determined. Then, a dual-layer hierarchical optimization framework is used to optimize the meta-action unit. This method selects the gearbox of typical collaborative system as the optimization design objective. And the multi-objective marine predator algorithm is used to solve it. The results show that the motor efficiency of wheel loader and dump truck increased to 87.13% and 85.64% respectively. The energy consumption of a single operating cycle was reduced by 1.55% and 5.69% respectively, battery cycle life increased by 1.32% and 4.69%. Furthermore, the daily operation cost of the collaborative system is reduced by 2.61%. The proposed optimization design method can be broadly applied in the optimization design of collaborative systems.

A new multi-stage coordinated power system planning method considering renewable energy access

When renewable energy is connected to the new power system, it will affect the normal operation of some energy storage equipment, resulting in too small internal generation capacity of the new power system and insufficient capacity of the new power system. Therefore, based on the consideration of renewable energy access, a new multi-stage coordinated planning method for power system is studied. This paper analyzes the demand for peak shaving capacity of the new power system and determines the access point of renewable energy. a new multi-stage coordinated planning model of power system is built, and the method of multi-stage coordinated planning of power system is studied by solving the model. Set up the experimental environment, give the parameters of the experimental equipment, and design the comparative experiment. The results show that the coordinated planning method studied in this paper can help to reduce the operation cost of the new power system and ensure the economic benefits of the new power system.

Study on the optimal allocation of comprehensive energy in the park

According to the demand response mode of the user side, this paper divides the flexible load into translational, reducible and transferable loads, briefly analyzes and introduces the operation characteristics of the three loads, and constructs the park comprehensive energy source system including wind power generation, photovoltaic, gas turbine and gas boiler. Considering the system investment cost, operation cost, fuel cost and compensation cost, this paper constructs the optimal allocation model of electric heating system in the park with the optimal total cost, and optimizes it through YALMIP in MATLAB. The final results show that the participation of flexible load and electric heating energy storage can not only effectively reduce the initial investment cost and total system cost in the early stage of the park, but also reasonably adjust the load curve, the optimal output point of energy storage equipment is obtained to determine the capacity of energy storage equipment.

Optimisation of regional energy demand networks based on flexible load model

The existing literature on integrated energy station-grid planning studies focuses on configuration planning. Therefore, a multi-objective hybrid particle swarm algorithm is used in this paper to solve a multi-objective optimisation model and combines a multi-indicator evaluation method based on evidence-based reasoning to select the solution with the highest evaluation value from multiple candidates (Pareto solution set) as the optimal solution. The optimal planning solution is selected from multiple candidates (Pareto solution set) by a multi-indicator evaluation method based on evidence-based reasoning, and the effectiveness of the proposed model is verified utilizing an example. The customer participation demand response optimises the demand curve by adjusting the flexible load, reduces the system operation cost and investment construction cost, and maximises the economic, environmental and reliability benefits of the integrated regional energy station grid.

The assessment of solar photovoltaic in Poland: the photovoltaics potential, perspectives and development.

The following article explains the current condition of the photovoltaics sector both in Poland and worldwide. Recently, a rapid development of solar energy has been observed in Poland and is estimated that the country now has about 700,000 photovoltaics prosumers. In October 2021, the total photovoltaics power in Poland amounted to nearly 5.7 GW. The calculated technical potential of photovoltaics in Poland is 153.484 PJ (42.634 TWh). This would cover 26.04% of Poland’s electricity needs. The main aim of the article is to assess the level of development of the photovoltaic market in Poland, the genesis of its creation, description of the current situation and determination of the development opportunities. As part of the aim, programs supporting the development of solar energy in Poland have been described and the SWOT analysis has also been performed. The strengths of photovoltaics include high social acceptance and low costs of photovoltaics system operation, while opportunities include rapidly increasing technological efficiency and decreasing cost of solar systems. On the other hand, weaknesses include the high costs of photovoltaics systems and the disparities in the amount of solar energy reaching the market during the year, whereas climate change and the coronavirus pandemic are threats. In 2020, PV became an investment hit in the energy sector and an economic driver in Poland. In the difficult time of two lockdowns caused by the global pandemic, domestic PV made a significant contribution to the maintenance of investment processes in the amount of PLN 9.5 billion and provided Poland with 35 thousand jobs. In 2020, 1.5% of the country’s electricity came from PV sources. In 2021, it will be 3.5%, and by 2025, solar energy will provide approx. 10% of Poland’s electricity. It is worth examining the development of photovoltaics from a broad and long-term perspective. The spectacular development of photovoltaics in Poland is due to hitting the right time window and reducing technology costs, but most of all, it is based on the cooperation of stakeholders and trust in the regulatory environment.Graphical abstract

Study on energy management model of integrated New Energy-Storage-Charging system considering the influence of uncertainties

The energy management of the integrated New energy-Storage-Charging system is affected by many source-side and load-side uncertainties, making it difficult for the system operator to choose an appropriate operation scheme. To deal with the influence of various uncertainties on the operation optimization effect of the integrated New energy-Storage-Charging system and provide an effective theoretical basis for the system operator to formulate the operation scheme, this paper studies the energy management of the integrated New energy-Storage-Charging system considering various uncertain factors. First, it constructs an equipment operation model of the integrated New energy-Storage-Charging system and charging load regulation model of the electric vehicle and analyzes the influence of five uncertainties such as temperature, light intensity, wind speed, load, and electricity price on the system operation. Then, considering the load transfer cost, it establishes the energy management model of the integrated New energy-Storage-Charging system to minimize the system operation cost. Finally, based on the downside risk theory, it constructs a risk management model of the system operation considering multi-dimensional uncertainty. By imposing constraints for uncertainty management, we have the system operation optimization schemes under different risk levels. The case analysis shows that the optimization proposed in this paper can accurately adjust a load of electric vehicles to a single vehicle and reduce the operation cost of the system by participating in the demand response by load regulation. In addition, this paper proposes an effective quantitative description method and risk dealing scheme for the influence of various uncertainties.

Distributed neurodynamic-based economic dispatch strategy for we-energy

This paper investigates the distributed collaborative energy management of distributed cyber-energy system with consideration of multiple types of coupled energy sources and loads. Firstly, the energy structure of We-Energy (WE) and the characteristics of multi-energy interconversion are studied. With this effort, the concept of general loads are modeled based on transform loss and compensation coefficient, which enables multiple controllable loads interconverting with each other to reduce energy consumption. As a result, the system capacity costs can be greatly reduced. Furthermore, a new fully distributed neurodynamics-based algorithm is proposed to solve the economic dispatch problem of multiple WEs. The proposed method can only use seldom shared variables to obtain the optimal solutions and does not require the objective function to be strictly convex and smooth in solving convex optimization problems. Meanwhile, the proposed possesses faster convergence speed by employing application-specific integrated circuits. Moreover, we prove that the proposed neurodynamics-based algorithm can asymptotically converge to the global optimal point based on Lyapunov analysis method. Finally, simulation results demonstrate the validity of the algorithm and the effect of general load on the overall operating cost of the WE system.

Distributed optimal energy scheduling for grid connected multi-microgrids with architecturized load characteristics

This paper proposes load characteristics-based multiple microgrids (Ch-MMGs) architecture and utilizes distributed model predictive control (DMPC) based energy management for its day-ahead scheduling in grid-connected mode. Different from existing work, which consider MMG with composite load architecture, the MMG architecture is re-organized by categorizing consumer’s load into different groups according to their operational characteristics. By doing so, each characteristics microgrid (Ch-MG) would have specific load pattern, which can significantly improve power utilization more economically and optimally. Demand Response Program (DRP) is incorporated for reducing the peak load demand of categorized groups in accordance to Time-of-Use (ToU) prices. In order to meet the supply and demand of each Ch-MG more economically, a DMPC based two level optimal energy scheduling scheme has been developed, where distributed network operator (DNO) acts as coordinating entity at upper level. It facilitates economic energy exchange among Ch-MMGs through providing optimal reference signal to Ch-MG at lower level. The Ch-MG performs local optimization in according to reference signal from upper level DNO. The uncertainty in renewable power generation are handled with probabilistic scenarios using Monte-Carlo simulation. Comparative case studies are conducted on conventional and proposed MMG architecture. The results indicate that the operation of individual MGs with proposed scheme can effectively reduce system operation cost and achieve system-wide and local supply–demand balance more economically.

A systematic analysis of integrating variable wind power into Fujian power grid

To realize the carbon emission peak and carbon neutrality objectives in China, efforts should focus on the electricity system, with an emphasis on creating low-carbon and renewable energy sources. The improvement of installed capacities of variable wind power and photovoltaics in the power system affect the entire power system. With the relatively independent power system of Fujian Province as an example, this study comprehensively considers the startup/shutdown, ramp-up/down, and power generation costs of the generators. Furthermore, the study uses the multi-period direct-current optimal power flow with unit-commitment method to analyze the impacts of variable wind power on the outputs of generators in the power system. The results show that at the current wind power-capacity level, the power system can still achieve the optimal dispatch without wind curtailment, and the marginal cost of wind power is relatively low. With further improvement of the installed capacity of wind power, it is necessary to fully mobilize the flexibility of all generators and PSHs, which will raise the overall operating cost of the whole power grid system. Finally, the study concludes with some policy recommendations for lowering the systematic integration cost of variable renewables.

Cost-Effectiveness of CCTV Surveillance Systems: Evidence from a Polish City

Closed-circuit television (CCTV) surveillance has been increasingly popular worldwide as a crime prevention measure, while its effectiveness, efficiency, and related privacy issues are debated. In this paper, we investigated whether the municipal CCTV surveillance system is cost-effective in the case study of Poznan, Poland. The analysis comprised (a) the preventive effectiveness of CCTV, (b) costs of CCTV surveillance system installation and operation, and (c) costs of crime. We collected police data on three categories of street crimes: (a) car burglary/theft, (b) car damage, and (c) robbery, as well as data on the costs of CCTV surveillance system construction and maintenance. We searched for a year after installing the CCTV system when the accumulated, hypothetical financial cost of crime was higher than the actual accumulated cost of crime and CCTV installation and maintenance in any treatment area. The number of crimes in a given category was predicted based on a comparable control area, where there were no cameras. Our study suggests that CCTV surveillance is cost-ineffective in most areas. This result implies the cautious development of CCTV surveillance, taking into account the target crime types and costs, including social costs and benefits. Evaluating cost-effectiveness, although considered as a robust measure, is in practice difficult. However, analysis of the correlation between land use characteristics and cost-effectiveness may provide practical advice on where to develop CCTV surveillance monitoring.

A distributed energy management scheme with the extended optimization horizon for Energy Internet

This paper proposes a distributed energy management with the extended optimization horizon for Energy Internet to minimize the system operation cost. The scheme dispatches various of controllable distributed energy sources of the traditional energy generation and battery energy storage devices. Two original contributions make the proposed scheme distinctive from the existing studies. Firstly, both the classical alternating direction method of multipliers (ADMM) and symmetric ADMM are combined in the new scheme to acquire fast and stable energy management policy, which improves the efficiency of energy management decisions. Secondly, an extended optimization horizon is designed based on the data from the previous day to simultaneously minimize the long-term cost and maintain battery state-of-charge. Simulation results from Pecan Street dataset demonstrate the superiority of the proposed method. Compared to existing distributed methods, the convergence time is reduced by almost 80% and the long-term cost is reduced by 47.8%. • A distributed energy management scheme is proposed for Energy Internet. • A hybrid ADMM is proposed for a fast and stable energy management policy. • An extended optimization horizon is designed to minimize the long-term cost. • The efficiency of the proposed scheme is verified through Pecan Street dataset.

Value of Interconnectors Operating in Simultaneous Energy-Frequency Response Markets

This paper investigates the potential contribution that interconnectors can provide to efficiently support the security of interconnected power systems. The proposed modelling setup introduces a radical paradigm shift in the operation of the interconnectors and in their interactions with multiple markets. To the best of our knowledge, this is the first paper that models a simultaneous allocation of the interconnector capacity for the exchange of energy and of inertia-dependent primary frequency response. The benefits and impact of this new methodology are evaluated with typical market indicators (e.g., social welfare and interconnector revenues) under two different paradigms: a centralized approach where the interconnectors are operated to minimize the system operational cost and a market-based framework where the interconnectors are privately-owned assets with self-interested objectives. By modelling the interconnectors as “price-maker”, the proposed work quantifies the potential inefficiencies of market solutions while considering key elements such as capacity withdrawing. A case study of the GB-France systems assesses the value of interconnectors on system efficiency and security under the considered paradigms.

Economic Optimal Scheduling of Wind–Photovoltaic-Storage with Electric Vehicle Microgrid Based on Quantum Mayfly Algorithm

The effectiveness of energy management systems is a great concern for wind–photovoltaic-storage electric vehicle systems, which coordinate operation optimization and flexible scheduling with the power grid. In order to save system operation cost and reduce the energy waste caused by wind and light abandonment, a time-sharing scheduling strategy based on the state of charge (SOC) and flexible equipment is proposed, and a quantum mayfly algorithm (QMA) is innovatively designed to implement the strategy. Firstly, a scheduling strategy is produced according to the SOC of the battery and electric vehicle (EV), as well as the output power of wind–photovoltaic generation. In addition, the minimum objective function of the comprehensive operation cost is established by considering the cost of each unit’s operation and electricity market sale price. Secondly, QMA is creatively developed, including its optimization rule, whose performance evaluation is further carried out by comparisons with other typical bionics algorithms. The advantages of QMA in solving the low-power multivariable functions established in this paper are verified in the optimization results. Finally, using the empirical value of the power generation and loads collected in enterprise as the initial data, the mayfly algorithm (MA) and QMA are executed in MATLAB to solve the objective function. The scheduling results show that the time-sharing scheduling strategy can reduce the system’s cost by 60%, and the method decreases energy waste compared with ordinary scheduling methods, especially when using QMA to solve the function.

Resilient outage recovery of a distribution system: co-optimizing mobile power sources with network structure

Outage recovery is important for reducing the economic cost and improving the reliability of a distribution system (DS) in extreme weather and with equipment faults. Previous studies have separately considered network reconfiguration (NR) and dispatching mobile power sources (MPS) to restore the outage load. However, NR cannot deal with the scenario of an electrical island, while dispatching MPS results in a long power outage. In this paper, a resilient outage recovery method based on co-optimizing MPS and NR is proposed, where the DS and traffic network (TN) are considered simultaneously. In the DS, the switch action cost and power losses are minimized, and the access points of MPSs are changed by carrying out the NR process. In the TN, an MPS dispatching model with the objective of minimizing power outage time, routing and power generation cost is developed to optimize the MPSs’ schedule. A solution algorithm based on iteration and relaxation methods is proposed to simplify the solving process and obtain the optimal recovery strategy. Finally, numerical case studies on the IEEE 33 and 119-bus systems validate the proposed resilient outage recovery method. It is shown that the access point of MPS can be changed by NR to decrease the power outage time and dispatching cost of MPS. The results also show that the system operation cost can be reduced by considering power losses in the objective function.

Microgrid Harmonic Mitigation Strategy Based on the Optimal Allocation of Active Power and Harmonic Mitigation Capacities of Multi-Functional Grid-Connected Inverters

Harmonic pollution sources in microgrids have the characteristics of high penetration and decentralization, as well as forming a full network. Local harmonic mitigation is a traditional harmonic mitigation method, which has the disadvantages of complexity and costly operation. Based on the idea of the decentralized autonomy of power quality, this paper establishes a comprehensive optimization model of the active power and harmonic mitigation capacities of grid-connected inverters based on two-layer optimization and realizes harmonic mitigation. Firstly, based on the harmonic sensitivity analysis, the calculation method of harmonic mitigation capacity is given. Secondly, a two-layer model of harmonic mitigation optimization is established. The upper-layer optimization model takes the minimum operation cost of the microgrid as the objective and the active power reduction in the multi-functional grid-connected inverter (MFGCI) as the optimization variable. The lower-layer optimization model offers the best harmonic mitigation effect as the objective and the harmonic current compensation as the optimization variable. According to the relationship between the total remaining capacity of MFGCI and the capacity required for harmonic mitigation, there are three different objective functions in the lower-layer optimization model. Then, the model solving steps are provided. Finally, an example shows that the proposed optimization model can achieve harmonic mitigation at different times. Compared with the case without active power optimization, the operation cost of the whole system can be reduced by up to 14.6%, while ensuring the harmonic mitigation effect. The proposed method has the advantages of a harmonic mitigation effect and economical system operation.