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.     

基于盲数理论的智能变电站全寿命周期成本估算

为有效解决智能变电站全寿命周期成本分析过程中存在的多种不确定性因素的影响,在分析智能变电站各项成本特性的基础上引入盲数理论,建立了基于盲数理论的智能变电站全寿命周期成本理论估算数学模型。充分考虑资金的时间价值,分析了气体绝缘金属封闭式开关设备智能变电站和空气绝缘开关设备智能变电站融合盲数理论的全寿命周期成本的费用分解结构和计算方法。以某智能变电站为例进行计算分析,结果表明,与传统的确定性分析方法相比,所建模型能够计算出智能变电站全寿命周期成本的可能分布区间及其对应的可信度。     

房地产上市企业高管团队职能背景对绩效的影响

运用中国房地产上市公司的数据,区分企业短期会计绩效和长期价值成长能力,研究了高管团队职能背景对企业绩效的影响。研究结果表明:对房地产上市公司而言,高管团队职能背景异质性与企业短期会计绩效呈显著正相关关系,对企业长期价值成长能力的影响不大。在3 种一般职能背景中,仅支持型职能背景与企业绩效呈显著相关关系,且与企业短期会计绩效呈负相关关系,与长期价值成长能力呈正相关关系。在2 种特殊职能背景下,有政府背景的高管与企业长期价值成长能力呈显著正相关关系     

基于灰色模型的房地产开发企业战略成本管理风险评价

在房地产开发企业存在多个子公司、子公司有多个在建项目的条件下,针对房地产开发企业战略成本风险管理水平较难评判的情况进行研究。通过专家访谈与文献综合,以标准住宅的特征价格与项目战略成本对比作为专家评判的依据,建立了多项目房地产开发企业战略成本风险管理灰色综合评判模型,通过专家打分并对打分结果进行处理,从而评判房地产开发企业战略成本风险管理水平,减少了对风险管理水平判断的主观性。从实证结果来看,该方法较准确地判断出了当前企业的战略成本风险管理水平,为企业制定相关发展战略提供了依据,效果较显著,其科学性及实用性得到了初步验证。     

基于层次分析法的变电站工程造价关键指标分析

变电站工程造价影响因素众多,造价管控的难度较大,出现了变电站工程概算结余过多的现象,占用了过多的资金,造成了资金的浪费。为了有效地控制变电站工程概算,有必要研究影响工程概算的关键指标。基于安徽电网变电站工程2010~2015 年的历史造价数据,用于主成分分析对指标属性进行优化精简,应用相关分析确定了指标属性与变电站工程概算的相互关系,从而构建了变电站工程的关键指标体系。同时,在56 位专家问卷调查的基础上,应用层次分析法对变电站工程关键指标的重要性权重进行技术分析,为下一步构建变电站工程投资预测模型奠定了基础,有效地控制变电站工程概算。     

具有双冷液态锂铅包层的聚变动力电站经济性初步分析

利用聚变系统分析软件SYSCODE对具有双冷液态锂铅包层的聚变动力电站(FDS-Ⅱ电站)经济性进行了计算和分析。采用包层材料预期价格,对成本进行了计算,同时分析了成本与工程参数及包层材料价格不确定性因子的关系,为进一步改进FDS-Ⅱ设计提供参考。     

Energy use, cost and CO2 emissions of electric cars

We examine efficiency, costs and greenhouse gas emissions of current and future electric cars (EV), including the impact from charging EV on electricity demand and infrastructure for generation and distribution.Uncoordinated charging would increase national peak load by 7% at 30% penetration rate of EV and household peak load by 54%, which may exceed the capacity of existing electricity distribution infrastructure. At 30% penetration of EV, off-peak charging would result in a 20% higher, more stable base load and no additional peak load at the national level and up to 7% higher peak load at the household level. Therefore, if off-peak charging is successfully introduced, electric driving need not require additional generation capacity, even in case of 100% switch to electric vehicles.GHG emissions from electric driving depend most on the fuel type (coal or natural gas) used in the generation of electricity for charging, and range between 0 g km⁻¹ (using renewables) and 155 g km⁻¹ (using electricity from an old coal-based plant). Based on the generation capacity projected for the Netherlands in 2015, electricity for EV charging would largely be generated using natural gas, emitting 35-77 g CO_2 eq km⁻¹.We find that total cost of ownership (TCO) of current EV are uncompetitive with regular cars and series hybrid cars by more than 800 € year⁻¹. TCO of future wheel motor PHEV may become competitive when batteries cost 400 € kWh⁻¹, even without tax incentives, as long as one battery pack can last for the lifespan of the vehicle. However, TCO of future battery powered cars is at least 25% higher than of series hybrid or regular cars. This cost gap remains unless cost of batteries drops to 150 € kWh⁻¹ in the future. Variations in driving cost from charging patterns have negligible influence on TCO.GHG abatement costs using plug-in hybrid cars are currently 400-1400 € tonne⁻¹ CO_2 eq and may come down to −100 to 300 € tonne⁻¹. Abatement cost using battery powered cars are currently above 1900 € tonne⁻¹ and are not projected to drop below 300-800 € tonne⁻¹.     

Mapping woody-biomass supply costs using forest inventory and competing industry data

The goals of energy independence and sustainability have motivated many countries to consider biomass-based energy sources. The United States has substantial and increasing forest resources that could be used to produce both electricity and liquid fuel. However, these forest resources are highly heterogeneous in terms of the wood’s properties, the logging cost, the spatial distribution, and the value to other industries. These factors make predicting costs and selecting plant locations particularly challenging. When dealing with forest biomass, feedstock cost and location have frequently been highly simplified in previous studies. This paper presents a methodology for combining highly resolved forest inventory and price data with records of competing industries to develop detailed maps of feedstock availability. The feedstock sourcing strategy of the proposed bioenergy plants is modeled by a cost-minimizing linear program, as is the feedstock selection of the competing mills. A case study is performed on the southeast United States.     

Effect of optimal spinning reserve requirement on system pollution emission considering reserve supplying demand response in the electricity market

Pollution emission reduction is becoming an inevitable global goal. Incorporating pollution reduction goals into power system operation affects several different aspects, such as unit scheduling and system reliability. At the same time, changes in the energy scheduling change the required optimal reserve amount. Optimal spinning reserve scheduling also affects the energy market scheduling. Optimal reserve allocation changes the energy scheduling, which affect the amount of pollution emission. Therefore, incorporating pollution emission reduction and optimal spinning reserve scheduling cannot be studied separately. Analysis of the system effects of pollution reduction should be performed considering the ancillary service market, specificity the optimal spinning reserve scheduling. This problem is addressed in this paper by incorporating optimal spinning reserve scheduling in a combined environment economic dispatch (CEED) in one objective function. The framework of this paper enables the study of the effect of optimal reserve scheduling and emission reduction as well as an analysis of the system effects of pollution reduction. With the increased AMI and smart grid realization, the reserve supplying demand response (RSDR) is becoming an important player in the reserve market, and thus, these resources are also taken into account. In this paper, the objective function is social cost minimization, including the costs associated with energy provision, reserve procurement, expected interruptions and environmental pollution. A MIP-based optimization method is developed, which reduces the computational burden considerably while maintaining the ability to reach to the optimal solution. The IEEE RTS 1996 is used as a test case for numerical simulations, and the results are presented. The numerical results show that optimal reserve scheduling and RSDR utilization resources have a considerable impact on environmental–economic cost characteristics.     

Power generation using carbon mesh cathodes with different diffusion layers in microbial fuel cells

An inexpensive carbon material, carbon mesh, was examined to replace the more expensive carbon cloth usually used to make cathodes in air-cathode microbial fuel cells (MFCs). Three different diffusion layers were tested using carbon mesh: poly(dimethylsiloxane) (PDMS), polytetrafluoroethylene (PTFE), and Goretex cloth. Carbon mesh with a mixture of PDMS and carbon black as a diffusion layer produced a maximum power density of 1355 ± 62 mW m⁻² (normalized to the projected cathode area), which was similar to that obtained with a carbon cloth cathode (1390 ± 72 mW m⁻²). Carbon mesh with a PTFE diffusion layer produced only a slightly lower (6.6%) maximum power density (1303 ± 48 mW m⁻²). The Coulombic efficiencies were a function of current density, with the highest value for the carbon mesh and PDMS (79%) larger than that for carbon cloth (63%). The cost of the carbon mesh cathode with PDMS/Carbon or PTFE (excluding catalyst and binder costs) is only 2.5% of the cost of the carbon cloth cathode. These results show that low cost carbon materials such as carbon mesh can be used as the cathode in an MFC without reducing the performance compared to more expensive carbon cloth.