Power generation expansion planning with adaptive simulated annealing genetic algorithm

In this paper, an adaptive simulated annealing genetic algorithm is proposed to solve generation expansion planning of Turkey's power system. Least‐cost planning is a challenging optimization problem due to its large‐scale, long‐term, nonlinear, and discrete nature of power generation unit size. Genetic algorithms have been successfully applied during the past decade, but they show some limitations in large‐scale problems. In this study, simulated annealing is used instead of mutation operator to improve the genetic algorithm. The improved algorithm is applied to the power generation system with seven types of generating units and a 20‐year planning horizon. The planning horizon is divided into four equal periods. The new algorithm provides approximately 6.6 billion US$ (3.2%) cheaper solution than GA and also shows faster convergence. Copyright © 2006 John Wiley & Sons, Ltd.     

Investigating the need of nuclear power plants for sustainable energy in Iran

Over the decades, the consumption of all types of energy such as electricity increased rapidly in Iran. Therefore, the government decided to redevelop its nuclear program to meet the rising electricity demand and decrease consumption of fossil fuels. In this paper, the effect of this policy in four major aspects of energy sustainability in the country, including energy price, environmental issues, energy demand and energy security have been verified. To investigate the relative cost of electricity generated in each alternative generator, the simple levelized electricity cost was selected as a method. The results show that electricity cost in fossil fuel power plants presumably will be cheaper than nuclear. Although the usage of nuclear reactor to generate power is capable of decreasing hazardous emissions into the environment, there are many other effective policies and technologies that can be implemented. Energy demand growth in the country is very high; neither nuclear nor fossil fuel cannot currently cope with the growth. So, the only solution is rationalizing energy demand by price amendment and encouraging energy efficiency. The major threats of energy security in Iran are high energy consumption growth and economic dependency on crude oil export. Though nuclear energy including its fuel cycle is Iran's assured right, constructing more nuclear power plants will not resolve the energy sustainability problems. In fact, it may be the catalyst for deterioration since it will divert capital and other finite resources from top priority and economic projects such as energy efficiency, high technology development and energy resources management.     

Techno‐economic optimization of hybrid power system using genetic algorithm

This paper presents an optimum sizing methodology to optimize the hybrid energy system (HES) configuration based on genetic algorithm. The proposed optimization model has been applied to evaluate the techno‐economic prospective of the HES to meet the load demand of a remote village in the northern part of Saudi Arabia. The optimum configuration is not achieved only by selecting the combination with the lowest cost but also by finding a suitable renewable energy fraction that satisfies load demand requirements with zero rejected loads. Moreover, the economic, technical and environmental characteristics of nine different HES configurations were investigated and weighed against their performance. The simulation results indicated that the optimum wind turbine (WT) selection is not affected only by the WT speed parameters or by the WT rated power but also by the desired renewable energy fraction. It was found that the rated speed of the WT has a significant effect on optimum WT selection, whereas the WT rated power has no consistent effect on optimal WT selection. Moreover, the results clearly indicated that the HES consisting of photovoltaics (PV), WT, battery bank (Batt) and diesel generator (DG) has superiority over all the nine systems studied here in terms of economical and environmental performance. The PV/Batt/DG hybrid system is only feasible when wind resource is very limited and solar energy density is high. On the other hand, the WT/Batt/DG hybrid system is only feasible at high wind speed and low solar energy density. It was also found that the inclusion of batteries reduced the required DG and hence reduced fuel consumption and operating and maintenance cost. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimization of a building's cooling plant for operating cost and energy use

An optimal neural network-based controller for an ice thermal storage system has been developed and tested. The controller consists of four neural networks, three of which map equipment behavior and one that acts as a global controller. The controller self-learns equipment responses to the environment and then determines the control settings required to minimize operating cost. It has the advantage over other controllers in that it always remains calibrated. Since it does not rely upon rules or assumptions, it is able to provide optimal control under any utility pricing and operating condition. Although originally designed to minimize operating costs, simulation and optimization techniques often determine minimum energy use as well.     

Operating schedule of a combined energy network system with fuel cell

The chromosome model showing system operation pattern is applied to GA (genetic algorithm), and the method of optimization operation planning of energy system is developed. The optimization method of this operation planning was applied to the compound system of methanol‐steam‐reforming‐type fuel cell, geothermal heat pump and the electrolysis tank of water. The operation planning was performed for the energy system using the energy demand pattern of the individual residence of Sapporo city. From analysis results, the amount of outputs of a solar module and the relation of the operation cost of the system, which are changed by the weather were clarified. The representation day in February of the ratio of the operation cost in case of (0% of output rates) the rainy weather to the time of fine weather (100% of output rates) is 1.12. And the representation day in July is 1.71. Furthermore, the optimal capacity of accumulation of electricity and thermal storage was estimated, and they are 308 and 23 MJ, respectively. Copyright © 2006 John Wiley & Sons, Ltd.     

回热式闭式空间核能布雷顿循环系统性能分析及优化

随着深空探测的不断发展,作为最具发展潜力的能源之一,空间核动力在国内外得到大量关注和研究.空间核动力系统中热电转换技术至关重要,在大功率阶段下,布雷顿循环动态热电转换系统因其功率较大,效率较高等优点得到广泛应用和发展,对其进行特性分析和参数优化具有重要意义.对运用闭式布雷顿循环的次临界安全空间(S4)反应堆系统建立回热...     

Loss cost reduction and power quality improvement with applying robust optimization algorithm for optimum energy storage system placement and capacitor bank allocation

Power losses cause the underutilization of distributed generation (DG) units in addition to the cost increasing in microgrid. Minimizing these losses has been focused in many papers. Using energy storage system (ESS) is a crucial solution for loss reduction. ESS can balance the power exchange in on-peak times where its location and size optimization can improve the microgrid efficiency and reduce the loss cost significantly. Moreover, to ensure the power quality by improving the voltage profile, capacitor bank can be installed optimally on some buses. Optimization of size and location of the capacitor bank can enhance the reactive power that is leading to power loss reduction. In other words, the capacitor bank is applied to compensate the total reactive power and consequently, the current is reduced that results in power loss reduction. In this article, the problem is defined as the optimum location and size of ESS and capacitor bank in the microgrid. Due to the complexity of the problem in many options for selecting the buses to implement these elements (ESS and capacitor bank), robust approach using the particle swarm optimization algorithm and general algebraic modeling system are applied for optimization process. In addition, the uncertainty of renewable DGs such as photovoltaic and wind turbine is modeled by probability density functions and Monte-Carlo is used for selecting more probable cases in optimization processes. The results show the loss cost reduction and improvement in voltage and power profile with less fluctuations and more stability.     

Modeling of integrated renewable energy system for electrification of a remote area in India

Over the years, renewable energy based power generation has proven to be a cost-effective solution in stand-alone applications in the regions where grid extension is difficult. The present study focused on the development of models for optimal sizing of integrated renewable energy (IRE) system to satisfy the energy needs in different load sectors of four different zones considered in Chamarajanagar district of Karnataka state in India. The objective of the study is to minimize the total cost of generation and cost of energy using genetic algorithm (GA) based approach. Considering optimization power factor (OPF) and expected energy not supplied (EENS), optimum system feasibility has been investigated. Based on the study, it has been found that IRES is able to provide a feasible solution between 1.0 and 0.8 OPF values. However, power deficit occurs at OPF values less than 0.8 and the proposed model becomes infeasible under such conditions. Customer interruption cost (CIC) and deficit energy (DE) for all zones were also computed to quantify the reliability of the systems.     

Designing effective and efficient incentive policies for renewable energy in generation expansion planning

We present a bilevel optimization approach to designing effective and efficient incentive policies for stimulating investment in renewable energy. The effectiveness of an incentive policy is its capability to achieve a goal that would not be achievable without it. Renewable portfolio standards are used in this paper as the policy goal. The efficiency of an incentive policy is measured by the amount of policy intervention, such as taxes collected or subsidies paid, to achieve the policy goal. We obtain the most effective and efficient incentive policies in the context of generation expansion planning, in which a centralized planner makes investment decisions for the energy system to serve projected demand of electricity. A case study is conducted on integrated coal transportation and electricity transmission networks representing the contiguous United States. The numerical analysis from the case study provides insights on the comparison of various incentive policies. The sensitivity of the incentive policies with respect to coal production cost, wind energy investment cost, and transmission capacity is also studied.     

A practical method for evaluating the real cost of electrical energy

It is widely accepted that electric energy production from fossil fuels has a significant environmental impact. This impact can be estimated if the energy cost is calculated in terms of real economy. Many experts have tried to quantify the real cost by evaluating the damages occasioned to mankind and the environment during the entire fuel cycle. In this work, we propose a practical alternative method based on the philosophy of avoiding the damage rather than paying for it. The method assumes as a reference a new type of power plant equipped with all devices suitable to reduce the chemical pollutants down to a desired environmental standard. The result is an increasing factor which should be accounted for when calculating the present energy cost. The method has been applied to roughly estimate the mentioned increasing factor in a grid of central power stations typical of industrialized countries with the prevalent dependence on fossil fuels. Under the hypothesis of reducing the pollutant emissions (including carbon dioxide) by a factor of 10 and accounting for social costs related to the fuel cycle and the waste disposal, a factor larger than 3 between real and internal costs was found.     

中国核电站节能减排问题研究

介绍核电发展现状及其节能减排意义,提出核电节能减排应坚持“引进、利用、改造、创新和安全”的“十字”原则,通过费用投入与节约、燃料节约、节电、节水、系统设备节能、三废处理等途径来实现。明确核电节能减排的意义和必要性,把握核电节能减排的原则,按照核电节能的正确途径实施,才能安全、合理地发展核能事业。     

上海终端消费能源缺能损失分析

能源供应安全已成为上海经济社会发展必须高度重视的瓶颈之一。本文将能源投入作为独立变量引入生产函数,同时考虑技术进步的影响,建立了三要素生产函数模型,从中导出缺能损失计算公式,并定量分析能源供应安全对上海经济产出的影响。     

解析中国的核能战略

分析了我国发展核电三步走的战略（第一步压水堆核电站,第二步快中子增殖堆电站和第三步核聚变堆电站）及发展核电所需要的铀资源储备（重视国内外的铀资源利用）,进而对核燃料循环中的乏燃料后处理及乏燃料处置分离和嬗变技术（加速器驱动的次临界系统ADS）进行了讨论。     

Estimating Petroleum Exergy Production and Consumption Using a Simulated Annealing Approach

This study deals with the development of the petroleum exergy production and consumption relations in order to better analyze exergy values and predict the future projections using the simulated annealing (SA) approach, which is a powerful technique used to solve many optimization problems. The exergy estimation is performed based on the indicators of gross domestic product (GDP) and the percentage of vehicle ownership figures in Turkey, which is given as an illustrative example. The so-called SA exergy production and consumption (SAPEX) model is developed, while the exergy values obtained using the SAPEX model are also compared with those using the genetic algorithm (GA) approach. It is determined that the SAPEX model developed predicts the exergy values better than the GA model. It may be concluded that the models proposed here can be used as an alternative solution and estimation technique to available estimation techniques in predicting the future energy and exergy utilization values of countries. This study is also expected to give a new direction to engineers, scientists, and policy makers in implementing energy planning studies and in dictating the energy strategies as a potential tool.     

Optimum energy evaluation and life cycle cost assessment of a hydrogen liquefaction system assisted by geothermal energy

In this study, analyses of the thermodynamic performance and life cycle cost of a geothermal energy-assisted hydrogen liquefaction system were performed in a computer environment. Geothermal water at a temperature of 200 °C and a flow rate of 100 kg/s was used to produce electricity. The produced electricity was used as a work input to liquefy the hydrogen in the advanced liquefaction cycle. The net work requirement for the liquefaction cycle was calculated as 8.6 kWh/kg LH₂. The geothermal power plant was considered as the work input in the liquefaction cycle. The hydrogen could be liquefied at a mass flow rate of 0.2334 kg/s as the produced electricity was used directly to produce liquid hydrogen in the liquefaction cycle. The unit costs of electricity and liquefied hydrogen were calculated as 0.012 $/kWh and 1.44 $/kg LH₂. As a result of the life cycle cost analysis of the system, the net present value (NPV) and levelized annual cost (LAC) were calculated as 123,100,000 and 14,450,000 $/yr. The simple payback period (N_spp) and discount payback period (N_dpp) of the system were calculated as 2.9 and 3.6 years, respectively.     

A generic methodology to evaluate economics of hydrogen production using energy from nuclear power plants

Hydrogen, the deemed future transportation fuel can be produced from nuclear assisted energy sources. Assessment of economics of hydrogen production using energy from nuclear power plants is vital for asserting its competitiveness with competing technologies. A generic method is presented in this paper to evaluate Levelised Hydrogen Generation Cost, based on the discounted cash flow analysis. The method is illustrated by consideration of a typical case of hydrogen production via conventional electrolysis using electrical energy supplied from a pressure tube type boiling light water cooled heavy water moderated reactor concept.     

基于单耗分析法的核电机组能耗分布评价

单耗分析法是基于热力学第二定律以分析产品单耗结构作为降耗指标的能耗评价方法。核电系统遵循单耗分析方法,其能耗评价方式可以分为:标准燃料损耗化及附加单耗分布形式和标准煤耗化及其附加单耗分布形式,体现出不同标准燃料下的能耗分布状况。针对国内最新引进的第三代非能动压水堆AP1000机组进行拓展研究,在保证核电机组安全运行的前提下,提高堆芯对一回路换热温度等级,同时相应提高二回路汽轮机系统工质参数,对提高核电机组效率有显著作用;常规岛中减小蒸汽湿度,有助于降低回热系统能耗。     

Modeling and daily operation optimization of a distributed energy system considering economic and energy aspects

This paper presents a distributed energy system (DES) for a local district and formulates a constrained nonlinear multiobjective optimization model for the daily operation of the system. The main objective of the study is to increase the efficiency by minimizing energy cost, energy consumption, and energy losses. It is implemented through the integration and complementation of renewable energies and fossil fuels as well as the recycling utilization of waste heat in the DES. The consideration of network topology and energy losses of water heating network could also contribute to the improvement of energy efficiency. To solve the optimization problem, a novel Whale Optimization Algorithm is employed. Furthermore, the economic and energy performance of the DES are evaluated and compared with that of conventional centralized energy systems, ie, the EG and MG energy‐supply modes. After simulation studies, the hourly optimal energy (both natural gas and electricity) purchasing schedule as well as the hourly optimal set points of mass water flow rates and supply/return water temperatures could be determined. The results show that the DES saves more than 50% of energy costs/energy consumption than the MG mode and over 22% than the EG mode for a whole day, verifying the competitive advantage and great potential of both energy saving and cost reduction of the DES.     

Increasing capacity of a nuclear power plant unit using the hydrogen-fueled feedwater heating system

The article considers a novel approach to a challenging issue of modern power systems related with the future of nuclear power energy as having clear environmental advantages. To solve the problem, a number of alternative ways of using hydrogen fuel as a source of clean energy were proposed, which are aimed to increase the capacity and maneuverability of operating and designed two-circuit nuclear power plants (NPPs) with installed water coolants. In particular, it was suggested to use hydrogen energy to improve the performance of steam generators and capacity of NPP units by heating the feedwater. The revealed economic benefits of the given approach include the effect from replacing environmentally harmful stations based on gas turbine units. A research was made into the impact of pressure in the hydrogen-oxygen combustion chamber on the effectiveness of the proposed solutions. The necessary design parameters to the hydrogen heating system, the gross and net power ratings of the power unit, and the net present value were determined. It is shown that lowering the pressure in the hydrogen-oxygen combustion chamber leads to the increase in the net present value by 24 to 71 million dollars and by 43 to 90 million dollars for the operating and designed NPPs, respectively. Meanwhile, using the proposed approach to the designed NPPs can ensure a higher capacity for the power units, which equals 179 and 163 MW at atmospheric and elevated pressures, respectively. The efficiency of off-peak energy may equal 26.25 to 27.21 and 26.53% to 27.55% for the operating and designed NPPs, respectively. It should be noted that the proposed schematics prove to be economically competitive across the marginal cost of off-peak energy. The accrued net present value equals 106 to 404 million dollars and 170 to 468 million dollars at the elevated pressure, and 130 to 475 million dollars and 213 to 558 million dollars at the atmospheric pressure for the operating and designed NPPs, respectively.     

风力-生物质能联合发电系统在微电网中的扩展规划

提出了基于改进遗传算法的风力-生物质能联合发电系统在微电网中的扩展规划模型,在寻求总成本最小的扩展方案的同时,使微电网可靠性更高,而且满足系统规划和运行的非线性约束条件。在规划总成本中,不但包含机组投资的建设费用和运行费用,而且把电力供给不足所导致的需求侧停电损失成本也考虑在内。在模型中采用了适应性权重和方法构造双目标函数,很好地协调了成本和可靠性的问题。计算表明,文章所提出的模型和算法是可行、有效的,能对智能电网和分布式发电的规划和设计提供一定的理论依据和技术支持。