Joint economic and emission dispatch in energy markets: A multiobjective mathematical programming approach

Economic load dispatch is the method of determining the most efficient, low-cost and reliable operation of a power system by dispatching the available electricity generation resources to supply the load on the system. Environmental concerns that arise due to the operation of fossil fuel fired electric generators, change the classical problem into multiobjective emission/economic dispatch (MEED) which is formulated as a constrained nonlinear multiobjective mathematical programming (MMP). The proposed MEED formulation includes emission minimization objective, AC load flow constraints and security constraints of the power system which usually are found simultaneously in real-world power systems. The proposed model has a more accurate evaluation of transmission losses obtained from the load flow equations. The MMP approach based on ?-constraint algorithm has been proposed for generating Pareto-optimal solutions of power systems MEED problem. Moreover, fuzzy decision making process is employed to extract one of the Pareto-optimal solutions as the best compromise nondominated solution. The proposed approach is simulated on the IEEE 30-bus six-generator test system and obtained results have been comprehensively compared with some of the most recently published research in the area (from the both aspects of precision and execution tome) which confirms the potential and effectiveness of the proposed approach.     

An improved PSO for dynamic load dispatch of generators with valve-point effects

Dynamic load economic dispatch problem (DLED) is important in power systems operation, which is a complicated nonlinear constrained optimization problem. It has nonsmooth and nonconvex characteristics when generator valve-point effects are taken into account. This paper proposes an improved particle swarm optimization (IPSO) to solve DLED with valve-point effects. In the proposed IPSO method, feasibility-based rules and heuristic strategies with priority list based on probability are devised to handle constraints effectively. In contrast to the penalty function method, the constraint-handling method does not require penalty factors or any extra parameters and can guide the population to the feasible region quickly. Especially, equality constraints of DLED can be satisfied precisely. Furthermore, the effects of two crucial parameters on the performance of the IPSO for DLED are also studied. The feasibility and the effectiveness of the proposed method are demonstrated applying it to some examples and the test results are compared with those of other methods reported in the literature. It is shown that the proposed method is capable of yielding higher-quality solutions.     

Hybrid solar–wind domestic power generating system—a case study

A techno-economic study to design a hybrid solar photo-voltaic-wind domestic power generating system for a site on the western coast of India is described. The system uses short-term electrical power storage using lead-acid batteries, and auxiliary power from the A.C. mains power supply.The optimum system would be able to supply 84.16% of the annual electrical energy requirement of the site. The annualized cost of this power in Rs./kwh works out to be several times the present price of government supplied electricity.     

A method of economical load dispatch for steam turbine unit of thermal power plant

In this paper, by combining the equality differential increment theory (EDIT) with the equivalent polyhedron body (EPB) searching extremum strategy, a method of economical load dispatch for the steam turbine unit of the thermal power plant has been presented. Simultaneously, a method for the order of load shedding and the related optimal economic operational modes of each turbine unit in decreasing its load are ascertained. According to the methods, the results of the optimal economical dispatch of the peak loads, the order of load shedding and the related optimal economic operational modes of each turbine unit while decreasing the load of a certain thermal power plant have been obtained. These results are applied in the thermal unit, and its economic benefits are shown to be obviously higher than that of applying the relative efficiency of each turbine unit. The methods can be used as a reference for obtaining the optimum economical load dispatch for similar thermal power turbine units. Copyright © 2007 John Wiley & Sons, Ltd.     

A novel evolutionary algorithm for dynamic economic dispatch with energy saving and emission reduction in power system integrated wind power

An optimization algorithm is proposed in this paper to solve the economic dispatch problem that includes wind farm using the Chaotic Quantum Genetic Algorithm (CQGA). In addition to the detailed models of economic dispatch introduction and their associated constraints, the wind power effect is also included in this paper. The chaotic quantum genetic algorithm used to solve the economic dispatch process and discussed with real scenarios used for the simulation tests. After comparing the proposed algorithm with several other algorithms commonly used to solve optimization problems, the results show that the proposed algorithm is able to find the optimal solution quickly and accurately (i.e. to obtain the minimum cost for power generation in the shortest time). At the end, the impact to the total cost savings for power generation after adding (or not adding) wind power generation is also discussed. The actual implementation results prove that the proposed algorithm is economical, fast and practical. They are quite valuable for further research.     

基于最小变动成本煤耗率的电厂负荷优化分配

在传统的电厂负荷优化分配基础上,引入了能量价值理论和环境成本,推导出与电煤能价比和环境成本相关的机组变动成本煤耗率,建立了机组运行综合评价体系.以电厂变动成本煤耗率最小为目标,对某电厂机组进行负荷优化分配,结果表明:与发电煤耗率相比,采用变动成本煤耗率作为机组负荷优化分配的目标更经济,而且负荷越低,节能效果越显著;电煤能价比减小时,电厂总变动成本煤耗率大幅下降;环境成本会使电厂总变动成本煤耗率升高.     

Economic feasibility of electricity generation from wind farms: A case study

Environmental problems, population growth, and the recent energy crisis have emphasized the need for zero-emission technologies while also ensuring economic feasibility. This work presents the economic advantages of using wind energy for power generation in Iran. A theoretical model is developed, which predicts the output power under various geographical and operating conditions. The wind data (speed and direction) of 2-h interval long-term period from December 2010 to October 2015 was adopted and analyzed to evaluate the levelized costs of electricity (COE) for power generation from wind farms (Arsanjan, Lamerd, and Abadeh) for the year 2018 per time. The influence of two important geographical factors namely winds speed and air humidity on output power also was studied. The results showed that the output power increases continuously when the wind speed varies from 2.0 to 2.6 m/s probably due to the compression of air passing through the wind turbine.     

变压器负载经济调度方式的研究与应用

本文依据负载与变压器经济运行的关系,分析了通过削峰填谷和提高负荷率的方式来降低运行中电网的有功功率消耗和无功功率消耗,实例应用证明了电网经济调度节电效果显著,可为供电企业创造一定的经济效益。     

Enhancement of combined heat and power economic dispatch using self adaptive real-coded genetic algorithm

In this paper, a self adaptive real-coded genetic algorithm (SARGA) is implemented to solve the combined heat and power economic dispatch (CHPED) problem. The self adaptation is achieved by means of tournament selection along with simulated binary crossover (SBX). The selection process has a powerful exploration capability by creating tournaments between two solutions. The better solution is chosen and placed in the mating pool leading to better convergence and reduced computational burden. The SARGA integrates penalty parameterless constraint handling strategy and simultaneously handles equality and inequality constraints. The population diversity is introduced by making use of distribution index in SBX operator to create a better offspring. This leads to a high diversity in population which can increase the probability towards the global optimum and prevent premature convergence. The SARGA is applied to solve CHPED problem with bounded feasible operating region which has large number of local minima. The numerical results demonstrate that the proposed method can find a solution towards the global optimum and compares favourably with other recent methods in terms of solution quality, handling constraints and computation time.     

Adding wind power to a wind-rich grid: Evaluating secondary suitability metrics

As the quantity of renewable electricity generation from wind farms increases in a region, the costs associated with integrating it into the broader electricity system also grow. This is primarily due to the need for dispatchable generators that vary power output to compensate for wind farm power variations. Such “balancing services” are an economic cost to the system that is typically not passed on to wind farms. We propose including the use of technical merits other than capacity factor and cost of energy for evaluating new wind farm sites and present a new graphical geospatial method, with the intention of identifying sites that minimize the need for additional electricity balancing service and transmission congestion. Specifically, locations with low correlation to existing wind farms, locations with high correlation to load, locations with high characteristic power time-shift from existing wind farms, and locations that relieve or do not negatively impact electricity transmission congestion are identified. A geospatial Venn diagram-based method of visualization is presented. These methods will equip regional planners with new tools to encourage wind farm development in areas that benefit the electricity grid beyond the lowest bid price.     

Integration of multiple passive load mitigation technologies by automated design optimization—The case study of a medium‐size onshore wind turbine

The present work considers the application to a medium‐size onshore wind turbine of passive load mitigation technologies, first individually and then integrated together. The study is conducted with the help of a comprehensive automated design optimization procedure, which eases the generation and comparison of consistent solutions, each satisfying the same overall requirements. Passive load mitigation is here obtained by inducing bend‐twist coupling to the blades. The coupling is generated by rotating the fibers of anisotropic laminates, by the aerodynamic sweeping of the blade and by offsetting the spar caps in opposite directions on the pressure and suction sides. The first two solutions yield significant benefits, while the third, for this particular wind turbine, is ineffective. In addition, the typical power losses associated with bend‐twist coupled blades are reduced by a novel regulation strategy that varies the fine pitch setting in the partial load region. After having considered each load mitigation technology by itself, fiber rotation and sweeping are combined together and used to design a rotor with a larger swept area. The final design generates cost of energy savings thanks to a large‐diameter, highly coned, soft‐in‐bending rotor that results in lower turbine costs and a higher energy capture compared with the baseline design.     

PG5301燃气轮机发电机组现状分析和修复的经济效益

某油田电厂PG5301燃气轮机发电机组运行时间不长,由于环境条件,进气过滤问题以及尖峰负荷运行时间过长使局部零件受损,降低了功率、效率和运行的可靠性,有可能在局部修复后就能获得较大的经济效益。     

100MW机组供热改造技术与经济指标比较

论述了黄台发电厂5号、6号机组节能供热改造技术的不同，由试验测量了机组改造后的经济指标，综述了机组改造投资、效果、工期与经济指标的差别。     

Interactive DE for solving combined security environmental economic dispatch considering FACTS technology

This paper presents an efficient interactive differential evolution (IDE) to solve the multi-objective security environmental/economic dispatch (SEED) problem considering multi shunt flexible AC transmission system (FACTS) devices. Two sub problems are proposed.The first one is related to the active power planning to minimize the combined total fuel cost and emissions, while the second is a reactive power planning (RPP) using multi shunt FACTS device based static VAR compensator (SVC) installed at specified buses to make fine corrections to the voltage deviation, voltage phase profiles and reactive power violation. The migration operation inspired from biogeography-based optimization (BBO) algorithm is newly introduced in the proposed approach, thereby effectively exploring and exploiting promising regions in a space search by creating dynamically new efficient partitions. This new mechanism based migration between individuals from different subsystems makes the initial partitions to react more by changing experiences. To validate the robustness of the proposed approach, the proposed algorithm is tested on the Algerian 59-bus electrical network and on a large system, 40 generating units considering valve-point loading effect. Comparison of the results with recent global optimization methods show the superiority of the proposed IDE approach and confirm its potential for solving practical optimal power flow in terms of solution quality and convergence characteristics.     

Optimal dispatch model for PV-electrolysis plants in self-consumption regime to produce green hydrogen: A Spanish case study

The production of green hydrogen from renewable energy by means of water electrolysis is a promising approach to support energy sector decarbonization. This paper presents a techno-economic model of plants with PV sources connected to electrolysis in self-consumption regime that considers the dynamics of electrolysis systems. The model calculates the optimal hourly dispatch of the electrolysis system including the operational states (production, standby, and idle), the load factor in production, and the energy imports and exports to the electricity grid. Results indicate that the model is a useful decision support tool to operate electrolysis plants connected to PV plants in self-consumption regimes with the target of reducing hydrogen production costs.     

Dual‐Doppler measurements of a wind ramp event at an Oklahoma wind plant

An observational case study of a wind ramp event at Enel Green Power North America's wind plant in Oklahoma is presented. Using coordinated measurements collected by the Texas Tech University Ka‐band radars, dual‐Doppler‐synthesized wind fields are merged with data from a meteorological tower and 32 operational turbines to document the evolution and impact of the wind ramp on turbine behavior and performance over a 1 h period. During the event, average power output for turbines within the dual‐Doppler analysis domain increases from 18.3% of capacity to 98.9% of capacity, emphasizing the abrupt impact wind ramp events can have on the electrical grid. The presented measurements and analyses highlight the insights remote sensing technologies can offer towards documenting transient wind ramps and assisting modeling efforts used to forecast such events. Copyright © 2015 John Wiley & Sons, Ltd.     

Development of a comprehensive MPPT for grid‐connected wind turbine driven PMSG

This paper proposes a comprehensive MPPT method by which extraction of maximum power from wind turbine and its subsequent transfer through various power stages and final delivery to the connected grid are realized. In the proposed system, the operation of the wind turbine at its maximum efficiency point is maintained by control of grid‐tied inverter such that the shaft speed of the generator is set to result the desired optimum tip speed ratio of the turbine. The proposed comprehensive MPPT estimates the required DC link voltage for each wind speed using a unified system model, uses a loss factor to account for the system losses, and then controls the inverter to push the WT extracted maximum power into the grid. The comprehensive MPPT is developed and is validated in MATLAB/Simulink platform in a wide range of operating wind speed. The results ascertain that the wind turbine is made to operate at its maximum efficiency point for all wind speeds below the rated one.     

计及风火系统聚合特性的虚拟电厂经济调度研究

提出一个VPP(虚拟发电厂)聚合出力特性的含新能源电网的两阶段经济调度模型。第一阶段基于包含若干风场与火电机组的VPP聚合出力特性决策VPP的总出力;第二阶段将总出力在VPP内部各发电单元之间进行分配。上述两个阶段都采用线性规划方法求解。基于IEEE—6母线电网的数值算例的计算结果表明,与传统经济调度方法相比,本研究提出的模型能降低风电弃风量近50%。     

干旱气候下基于风电并网的抽水蓄能电站经济调度模型

抽水蓄能电站配合风电出力有利于降低风电并网对电力系统的影响、提高电能质量、促进大规模风电并网,考虑到干旱气候可能制约抽水蓄能系统的发电和储存能力、进而影响风蓄联合系统的发电调度,以发电总可变成本的最小化为目标函数建立了基于风蓄联合系统的线性规划模型,评估了干旱气候对风蓄联合系统发电调度的影响,并利用变搜索半径优化的粒子群算法对模型进行求解。研究结果表明,干旱气候对风蓄联合系统的发电调度有较大的影响,且干旱气候可能促使系统二氧化碳排放量的增加,系统存储电能能力较强时,风电能有效促进二氧化碳减排;此外,算例分析还验证了所建模型的有效性。     

基于风电消纳的多类型储能系统联合经济调度

为使电力系统尽可能提高风电接纳能力,建立了基于风电消纳的实时失调成本模型,考虑到安全性、环保性,分别构建了基于风电-火电调度总成本模型和基于风电-火电-联合储能系统调度总成本模型,并采用HS-PSO混合算法求解调度总成本模型。算例仿真结果表明,抽水蓄能电站、蓄电池和超级电容器混合储能系统在增加经济效益、提高风电接纳能力方面优势明显;同时验证了储能系统容量与弃风率的关系,为含风电并网运行的系统经济调度提供了依据。