Impact on power planning due to demand-side management (DSM) in commercial and government sectors with rebound effect—A case study of central grid of Oman

This paper presents the results of a study that estimated the DSM energy saving and load management potential in commercial and government/institutional sectors in Oman (central grid area) and evaluated its impact on generation capacity and energy savings. The end-use (lighting and air-conditioning) energy consumption data have been collected in two major segments of the commercial sector for simplicity and to save time and money. Another unique aspect of the study is the inclusion of the energy savings, in transmission and distribution (T&D) losses that are estimated by using generation expansion planning approach. The study has found that DSM is financially beneficial from customers’ point of view as the discounted payback period of investment in efficient lighting and air-conditioning is between 4 and 12 years of the surveyed sample. From the utility point of view the capacity saving at the horizon year is between 372 and 596 MW and the overall energy saving for the whole planning horizon is about 29–44 TWh. The total avoided cost in generation and capacity saving is somewhere between 416 and 597 million dollars.     

Historical costs of coal-fired electricity and implications for the future

We study the cost of coal-fired electricity in the United States between 1882 and 2006 by decomposing it in terms of the price of coal, transportation cost, energy density, thermal efficiency, plant construction cost, interest rate, capacity factor, and operations and maintenance cost. The dominant determinants of cost have been the price of coal and plant construction cost. The price of coal appears to fluctuate more or less randomly while the construction cost follows long-term trends, decreasing from 1902 to 1970, increasing from 1970 to 1990, and leveling off since then. Our analysis emphasizes the importance of using long time series and comparing electricity generation technologies using decomposed total costs, rather than costs of single components like capital. By taking this approach we find that the history of coal-fired electricity suggests there is a fluctuating floor to its future costs, which is determined by coal prices. Even if construction costs resumed a decreasing trend, the cost of coal-based electricity would drop for a while but eventually be determined by the price of coal, which fluctuates while showing no long-term trend.     

Power system interconnection in developing countries and the equilibration of marginal costs

A method is proposed for the calculation of the benefits in power system interconnection which arise from the equilibration of marginal costs on the connected systems. The method is applied to the adjacent systems of Malaysia and Singapore. The benefits arising from the equilibration of marginal costs are shown to be significant compared to those which arise from the reduction of reserve margins.     

Market modeling for assessment of demand side programs using the marginal cost

Demand side management is nowadays considered as a fundamental step in the energy planning process. The criteria proposed for the assessment of the demand side programs (DSPs) are usually based on the balance between the marginal supply cost and the mean DSP cost. These criteria could not support the allotting of the invested capital to incentives for the consumers and advertising. This paper presents a methodology to support the utility planning at this point with more reliability. It proposes the expansion of the assessment criteria with the use of the marginal cost of the DSP. For the calculation of the DSP marginal cost, a dynamic model is developed and it is used for the simulation of the penetration of a DS Program. Using the ‘least‐cost’ criterion as the decision rule for the simulation, the planner has a distribution of the available investment capital throughout the whole planning period. The use of the ‘most‐value’ criterion supports the separation of the invested capital between incentives for the consumers and supportive expenses, e.g. advertising, marketing costs, etc. Copyright © 2000 John Wiley & Sons, Ltd.     

Electricity market auction settings in a future Danish electricity system with a high penetration of renewable energy sources - A comparison of marginal pricing and pay-as-bid

The long-term goal for Danish energy policy is to be free of fossil fuels through the increasing use of renewable energy sources (RES) including fluctuating renewable electricity (FRE).The Danish electricity market is part of the Nordic power exchange, which uses a Marginal Price auction system (MPS) for the day-ahead auctions. The market price is thus equal to the bidding price of the most expensive auction winning unit. In the MPS, the FRE bid at prices of or close to zero resulting in reduced market prices during hours of FRE production. In turn, this reduces the FRE sources’ income from market sales. As more FRE is implemented, this effect will only become greater, thereby reducing the income for FRE producers.Other auction settings could potentially help to reduce this problem. One candidate is the pay-as-bid auction setting (PAB), where winning units are paid their own bidding price.This article investigates the two auction settings, to find whether a change of auction setting would provide a more suitable frame for large shares of FRE. This has been done with two energy system scenarios with different shares of FRE.From the analysis, it is found that MPS is generally better for the FRE sources. The result is, however, very sensitive to the base assumptions used for the calculations.     

基于模糊隶属度的电力设备资产全寿命周期成本模型及评价体系研究

电网企业将LCC理论应用作为提高设备资产效率和质量的有效手段,亟需解决LCC应用中的模型计算和评价体系问题.本文通过构建电网企业资产全寿命周期管理机制,建立了电力设备的LCC的计算模型和方法,采用基于模糊数学中的模糊隶属度方法,改进了技改和大修项目分摊到多个设备资产分摊方法,提出了电力设备的LCC评价模型和评价体系,并...     

南方多省高峰限电对上海加强高峰期电力保障的启示

去年年底,我国南方多地接连发生用电紧张情况,多个省市更是在用电高峰时段对用户采取限电措施才勉强保障了本省电力供应的平稳。从电源侧结构、需求侧负荷等角度逐个剖析浙江、江西、湖南等省份限电的个中缘由,结果表明多省大范围缺电虽有去年冬天异常寒冷和大量境外订单转移国内引发制造业对电力需求大幅增长的外部原因,但政府管理上的死板和电力系统建设上的短板也是不应忽视的内部原因。上海作为国际大都市更是要全力避免限电事件的发生,今后应做好"三个关注",进一步提升上海市电力系统抵御风险能力。     

A study of Electrical Security Risk Assessment System based on Electricity Regulation

With the expansion of China's power system, there are more and more factors contributing to Large-area Power Outages. The snow disaster that hit Southern China in 2008 caused serious damages to the power systems, which made Chinese government realize that they cannot solely depend on power enterprises to effectively control the risk involved in power system. The Chinese government needs to collaborate with power enterprises in strengthening Electricity Regulation and taking countermeasures to reduce the risk of Large-area Power Outages. This paper first proposes an objective, practical and adaptive Electrical Security Risk Assessment System based on Electricity Regulation. The system consists of an assessment process with 278 indices, which are used to calculate the risk of Large-area Power Outages by the use of Analytic Hierarchy Process and the Delphi Method. Then, an example of Guangdong power system serves to illustrate the detailed implementation procedures of the proposed assessment system and the results show that Guangdong power system faces a moderate risk of Large-area Power Outages. Finally, some countermeasures are proposed to overcome the defects in the existing power system.     

GIS-based approach for defining bioenergy facilities location: A case study in Northern Spain based on marginal delivery costs and resources competition between facilities

This paper presents a GIS-based decision support system for selecting least-cost bioenergy locations when there is a significant variability in biomass farmgate price and when more than one bioenergy plant with a fixed capacity has to be placed in the region. The methodology tackles the resources competition problem between energy facilities through a location-allocation model based on least-cost biomass quantities. Whole system least delivery cost including intermediate bioenergy products is estimated. The methodology is based on a case study where forest wood residues (FWR) from final cuttings (FCs) are used to produce torrefied wood (TW) in two torrefaction plants (TUs) that supply a gasification unit (GU) in order to produce electricity. The provinces of Navarra, Bizkaia, Gipuzkoa, Alava, La Rioja, Cantabria and Burgos are assessed in order to find the best locations for settling down the TUs and the GU according to biomass availability, FWR and TW marginal delivery costs.     

Struggling to wean a society away from a century-old legacy of coal based power: Challenges and possibilities for South African Electric supply future

The challenges faced by the socio-political economy of South Africa when attempting to diversify away from a legacy of over a century of near exclusive dependence on cheap and abundant coal for its energy needs, particularly electricity, are discussed in this paper. Existing government policy documentation would appear to advocate for energy resource diversification. In addition the National Energy Regulator of South Africa (NERSA) published renewable energy feed-in-tariffs (REFIT) for renewable energy generation (during the first quarter of 2009) which were billed by the media as well as a range of stakeholders as very promising. Notwithstanding these seemingly appropriate measures there is still a near total lack of real progress on the ground in terms of serious renewable energy (RE) investments. The authors subsequently attempt to make some recommendations as to what might have probable chance of success in terms of overcoming the barriers to the adoption of a more diversified energy resource environment, in particular renewable energy (RE).     

Valuation of marginal CO2 abatement options for electric power plants in Korea

The electricity generation sector in Korea is under pressure to mitigate greenhouse gases as directed by the Kyoto Protocol. The principal compliance options for power companies under the cap-and-trade include the application of direct CO₂ emission abatement and the procurement of emission allowances. The objective of this paper is to provide an analytical framework for assessing the cost-effectiveness of these options. We attempt to derive the marginal abatement cost for CO₂ using the output distance function and analyze the relative advantages of emission allowance procurement option as compared to direct abatement option. Real-option approach is adopted to incorporate emission allowance price uncertainty. Empirical result shows the marginal abatement cost with an average of €14.04/ton CO₂ for fossil-fueled power plants and confirms the existence of substantial cost heterogeneity among plants which is sufficient to achieve trading gains in allowance market. The comparison of two options enables us to identify the optimal position of the compliance for each plant. Sensitivity analyses are also presented with regard to several key parameters including the initial allowance prices and interest rate. The result of this paper may help Korean power plants to prepare for upcoming regulations targeted toward the reduction of domestic greenhouse gases.     

Exergy-based method for analyzing the composition of the electricity cost generated in gas-fired combined cycle plants

The proposed method to analyze the composition of the cost of electricity is based on the energy conversion processes and the destruction of the exergy through the several thermodynamic processes that comprise a combined cycle power plant. The method uses thermoeconomics to evaluate and allocate the cost of exergy throughout the processes, considering costs related to inputs and investment in equipment. Although the concept may be applied to any combined cycle or cogeneration plant, this work develops only the mathematical modeling for three-pressure heat recovery steam generator (HRSG) configurations and total condensation of the produced steam. It is possible to study any n×1 plant configuration (n sets of gas turbine and HRSGs associated to one steam turbine generator and condenser) with the developed model, assuming that every train operates identically and in steady state. The presented model was conceived from a complex configuration of a real power plant, over which variations may be applied in order to adapt it to a defined configuration under study [Borelli SJS. Method for the analysis of the composition of electricity costs in combined cycle thermoelectric power plants. Master in Energy Dissertation, Interdisciplinary Program of Energy, Institute of Eletro-technical and Energy, University of São Paulo, São Paulo, Brazil, 2005 (in Portuguese)]. The variations and adaptations include, for instance, use of reheat, supplementary firing and partial load operation. It is also possible to undertake sensitivity analysis on geometrical equipment parameters.     

Hybrid optimization algorithm for modeling and management of micro grid connected system

In this paper, a hybrid optimization algorithm is proposed for modeling and managing the micro grid (MG) system. The management of distributed energy sources with MG is a multi-objective problem which consists of wind turbine (WT), photovoltaic (PV) array, fuel cell (FC), micro turbine (MT) and diesel generator (DG). Because, perfect economic model of energy source of the MG units are needed to describe the operating cost of the output power generated, the objective of the hybrid model is to minimize the fuel cost of the MG sources such as FC, MT and DG. The problem formulation takes into consideration the optimal configuration of the MG at a minimum fuel cost, operation and maintenance costs as well as emissions reduction. Here, the hybrid algorithm is obtained as artificial bee colony (ABC) algorithm, which is used in two stages. The first stage of the ABC gets the optimal MG configuration at a minimum fuel cost for the required load demand. From the minimized fuel cost functions, the operation and maintenance cost as well as the emission is reduced using the second stage of the ABC. The proposed method is implemented in the Matlab/Simulink platform and its effectiveness is analyzed by comparing with existing techniques. The comparison demonstrates the superiority of the proposed approach and confirms its potential to solve the problem.     

Implications of sustainability assessment for electricity system design: The case of the Ontario Power Authority’s integrated power system plan

This paper explores the results and implications of an illustrative application of a sustainability assessment framework in the design and evaluation of a major integrated power system plan. The paper examines the integrated power system plan developed by the Ontario Power Authority in 2007. The basic framework rests on a generic set of evaluation criteria reflecting basic requirements for progress towards sustainability that was adopted, reinterpreted and applied by the Authority in support of its proposed plan. In response to evident deficiencies in the Authority’s work, the authors and colleagues undertook a re-examination using a more fully elaborated sustainability assessment framework, specified for application to power system planning. The results point to a plan and plan components substantially different from those proposed by the Authority. More generally, the results highlight three advantages of applying such a sustainability assessment framework: comprehensive coverage of key requirements for progress towards sustainability while ensuring careful attention to the context and concerns of the sector; emphasis on identifying plan options that avoid major trade-offs among the sustainability criteria and recognition of interactions among the social, ecological, economic and technological realms favouring options that offer multiple, mutually reinforcing and lasting benefits.     

Probabilistic capacity of a grid connected wind farm based on optimization method

This paper proposes a new method to find the capacity of a future wind farm regarding several limits of the grid system: voltage stability limits, thermal limits, voltage limits, load tap changing limitation and generator power output limitation. The method combines the optimization method and a probabilistic analysis to maximize the number of the wind turbines subject to those limits. Two types of wind farms are modeled in this paper: fixed speed wind farms and variable speed wind farms. It is concluded that the proposed method is a fast and accurate method to deal with the uncertainty of wind energy in the planning of wind farm capacity.     

AGA (Asset Governance Assessment) for analyzing affect of subsidy on MC (Marginal Cost) in electricity distribution sector

Nowadays subsidy payments on electrical energy have to be managed and controlled to prevent any side effect particularly in developing countries. Effects of some external factors on Energy consumption and electricity distribution indices are analyzed in this paper. External factors are classified into three categories of social behavior, governance and urban planning. MC (Marginal Cost) of electricity in distribution is considered as the main index to be analyzed. Also, ANN (Artificial Neural Network) is applied to simulate effect of the mentioned factors on MC of distribution sector. Numerical investigation on the indices for a sample DISCO (Distribution Company) in Iran is made, results indicate that the more subsidies are allocated to consumers the more MC is increased. AGA (Asset Governance Assessment), which is proposed as a kind of governance decision, could improve the performance efficiency and avoid lose of activities done by DISCOs through subsidy management.     

Electricity supply on the island of Dia based on renewable energy sources (R.E.S.)

This paper presents a methodology for determining the specifications of an isolated R.E.S. power production system on an environmentally sensitive ecosystem. The wind and solar power constitute the primary power generation system and diesel generators act as backup. Real wind and solar potential measurements are used. The wind atlas of the island has been constructed. The specifications of the proposed system are optimized by the life cycle cost method. The renewable energy sources (R.E.S.) total annual energy production exceeds 90%. As a result, the dependence on the diesel generator set annual energy production is limited and the system’s operational cost is not practically influenced by the increasing fossil fuel prices. The introduction of a small size desalination plant for the production of drinkable water is also investigated. Both the available R.E.S. potential and the minimization of environmental impacts are considered for the siting of the equipment. The methodology of the present paper may be applied to other regions rich in R.E.S. potential, where the introduction of small size environmentally friendly isolated R.E.S. power systems is investigated.     

An evaluation method of energy storage technologies based on energetic costs

近年来，中国和世界一直致力于发展储能技术，为电网运行提供调峰、调频、黑启动、需求响应支持，并帮助解决可再生能源间歇性、不稳定性、不可调节性等问题。本文回顾总结了国内目前评价储能技术常用的技术指标和经济效益指标。并站在能源可持续发展的角度介绍了基于“能量”成本评价储能技术的新理念及方法，阐述了基于‘能量’成本评价不同技术节能潜力的必要性，引入了全生命周期能源投入存储回报（energy stored on Investment，ESOI）这一新指标。ESOI比值越高说明该技术“净能量”越高，生产对能源依赖度越低。本文研究对比了不同储能技术的ESOI，结果表明以压缩空气储能（CAES）和抽水储能（PHS）为代表的物理储能技术的ESOI远远大于电化学储能，其中，过去常用的铅酸电池（PbA）的ESOI最小，只有2。     

Design of innovative power conditioning system for the grid integration of thermoelectric generators

Recently, thermoelectric generators (TEGs) have emerged as a potential alternative for clean energy generation, due mainly to the technology innovation and the marked cost reduction of modules, as well as their distinctive advantages. In a TEG system, the electronic power conditioning system (PCS) plays a vital role in ensuring the effective power grid integration, since it is subject to requirements related not only to the variable thermal source itself but also to its effects on the grid operation. This paper proposes an enhanced structure of PCS for the grid integration of TEG arrays to maximize the energy capture from a variable heat source. The innovative topology employed consists of a Z-source inverter that allows the flexible, efficient and reliable generation of high quality electric power from the TEG array. A full detailed model is described and its control scheme is designed. The dynamic performance of the proposed systems is fully validated by computer simulation and experimental studies.