Risk-based optimal operation of hybrid power system using multiobjective optimization

ABSTRACT

This paper solves an optimal generation scheduling problem of hybrid power system considering the risk factor due to uncertain/intermittent nature of renewable energy resources (RERs) and electric vehicles (EVs). The hybrid power system considered in this work includes thermal generating units, RERs such as wind and solar photovoltaic (PV) units, battery energy storage systems (BESSs) and electric vehicles (EVs). Here, the two objective functions are formulated, i.e., minimization of operating cost and system risk, to develop an optimum scheduling strategy of hybrid power system. The objective of proposed approach is to minimize operating cost and system risk levels simultaneously. The operating cost minimization objective consists of costs due to thermal generators, wind farms, solar PV units, EVs, BESSs, and adjustment cost due to uncertainties in RERs and EVs. In this work, Conditional Value at Risk (CVaR) is considered as the risk index, and it is used to quantify the risk due to intermittent nature of RERs and EVs. The main contribution of this paper lies in its ability to determine the optimal generation schedules by optimizing operating cost and risk. These two objectives are solved by using a multiobjective-based nondominated sorting genetic algorithm-II (NSGA-II) algorithm, and it is used to develop a Pareto optimal front. A best-compromised solution is obtained by using fuzzy min-max approach. The proposed approach has been implemented on modified IEEE 30 bus and practical Indian 75 bus test systems. The obtained results show the best-compromised solution between operating cost and system risk level, and the suitability of CVaR for the management of risk associated with the uncertainties due to RERs and EVs.     

Use of Physical Sciences in Support of Environmental Management

Offshore drilling for oil and gas has been conducted since the early 1900s. Oil and gas under the seabed continue to be an important part of the energy resources of the United States. The need to balance the value of these resources against the potential for environmental damage is an important concern. This article explains why and how the Minerals Management Service (MMS) of the US Department of the Interior uses research in physical sciences to help fulfill its environmental goals, and it provides background information on the role of physical sciences in decision-making for Outer Continental Shelf (OCS) oil, gas, and other minerals development. Established in the 1970s, the MMS Environmental Studies Program is a highly focused marine research program designed to provide the environmental information necessary for OCS energy and nonenergy minerals planning and development activities. The physical sciences research supported by MMS includes physical oceanography, oil-spill risk analyses, atmospheric sciences, and sand and gravel studies. Instead of giving a comprehensive review on physical sciences research in MMS, this article presents sample MMS studies and illustrates how these studies are utilized to support decision-making in environmental management.Published online Note: This version was published online in June 2005 with the cover date of August 2004.     

A VSA-Based Strategy for Placing Conservation Buffers in Agricultural Watersheds

Conservation buffers have the potential to reduce agricultural nonpoint source pollution and improve terrestrial wildlife habitat, landscape biodiversity, flood control, recreation, and aesthetics. Conservation buffers, streamside areas and riparian wetlands are being used or have been proposed to control agricultural nonpoint source pollution. This paper proposes an innovative strategy for placing conservation buffers based on the variable source area (VSA) hydrology. VSAs are small, variable but predictable portion of a watershed that regularly contributes to runoff generation. The VSA-based strategy involves the following three steps: first, identifying VSAs in landscapes based on natural characteristics such as hydrology, land use/cover, topography and soils; second, targeting areas within VSAs for conservation buffers; third, refining the size and location of conservation buffers based on other factors such as weather, environmental objectives, available funding and other best management practices. Building conservation buffers in VSAs allows agricultural runoff to more uniformly enter buffers and stay there longer, which increases the buffers capacity to remove sediments and nutrients. A field-scale example is presented to demonstrate the effectiveness and cost-effectiveness of the within-VSA conservation buffer scenario relative to a typical edge-of-field buffer scenario. The results enhance the understanding of hydrological processes and interactions between agricultural lands and conservation buffers in agricultural landscapes, and provide practical guidance for land resource managers and conservationists who use conservation buffers to improve water quality and amenity values of agricultural landscape.     

Preliminary indoor radon risk assessment at the Poços de Caldas Plateau,MG-Brazil

This paper aims to present an assessment of the environmental radiological exposure at a Brazilian area of high natural radiation and discusses the indoor radon exposure risk. A survey of inhabitant exposures arising from the inhalation of radon progeny and external gamma exposure was conducted in urban and rural areas of the Po?os de Caldas Plateau, which is recognized worldwide as a high natural radiation region. The results of this survey indicated that highest radiation exposure was restricted to the rural area of Po?os de Caldas. The radiation exposure in urban locations was quite similar to the values observed in normal background areas in some Brazilian counties. By the application of a constant relative risk model, an additional 20% in the lifetime risk of lung cancer mortality due to the exposure to radon progeny was estimated at Po?os de Caldas. It was also estimated that 16% of all lung cancer deaths at Po?os de Caldas county could be attributable to radon exposure.     

关于城市应急供水系统建设的思考

从城市应急供水系统建设的紧迫性和重要性出发,分析了目前我国城市应急供水系统存在的问题和造成城市非常供水的原因。构建了城市应急供水系统的框架,将其分成工程措施和非工程措施两部分,并阐述了工程措施的类型和实施方法,以及非工程措施的各项应急机制,对建立、健全城市应急供水系统进行了探讨。     

面向2020年我国安全生产的若干战略问题思考

本文简要论述了我国现代化进程中安全生产工作的现状、发展趋势和面临的主要问题;围绕2020年实现全国安全生产状况根本性好转,安全生产水平达到或接近世界中等发达国家水平的中长期目标,分析探讨了安全专业人才、科技兴安、安全生产标准、安全培训、安全文化、中小企业安全生产与职业危害预防、土地使用安全规划与厂房选址安全、农业生产安全、公共安全与应急救援保障体系建设等若干战略问题。     

基于事故理论的城市轨道交通风险评价模型研究

笔者分析了城市轨道交通事故,在分析我国其他行业事故分类的基础上,确定城市轨道交通事故分类标准,即重大事故、大事故、险性事故和一般事故,并将不同事故分类情况及专家判断评分,按事故的大小不同换算成可以计算的计算尺度,根据事故种类不同计算出事故折算因子,根据风险理论的评价方法,建立了地铁风险评价模型,对地铁的危险性进行量化定级,并通过具体实例进行综合分析评价,该风险评价模型具有一定的工程意义。     

Demonstrating Floodplain Uncertainty Using Flood Probability Maps1

Abstract: The U.S. Federal Emergency Management Agency (FEMA) flood maps depict the 100‐year recurrence interval floodplain boundary as a single line. However, because of natural variability and model uncertainty, no floodplain extents can be accurately defined by a single line. This article presents a new approach to floodplain mapping that takes advantage of accepted methodologies in hydrologic and hydraulic analysis while including the effects of uncertainty. In this approach, the extents of computed floodplain boundaries are defined as a continuous map of flood probabilities, rather than as a single line. Engineers and planners can use these flood probability maps for viewing the uncertainty of a floodplain boundary at any recurrence interval. Such a flood probability map is a useful tool for visualizing the uncertainty of a floodplain boundary and represents greater honesty in engineering technologies that are used for flood mapping. While institutional barriers may prevent adoption of such definitions for use in graduated flood insurance rates (as most other insurance industries use to account for relative risks), the methods open the door technically to such a reality.     

AN EXAMINATION OF LAND USE - NUTRIENT EXPORT RELATIONSHIPS1

ABSTRACT: Lake and watershed management strategies and recent environmental legislation dictate that nonpoht nutrient sources associated with storm water runoff must be assessed. Accordingly, a nutrient flu assessment for phosphorus and nitrogen is conducted through an extensive literature review of nutrient export studies. These studies are reevaluated. The nutrient export coefficients are screened according to sampling design criteria and compiled according to land use. The ecological mechanisms within each land use influencing the magnitude of nutrient flux are also discussed     

乌鲁木齐市燃煤点源现状分析

对乌鲁木齐市燃煤点派数量、耗煤量、污染物的排放量以及在各功能区的分布分别进行了统计分析，对污染物的排放量在不同高度空间的分布也进行了统计分析，从而得出了确切的结论并提出了相应的建议。