Estimating Power Outage Costs Based on a Survey of Industrial Customers

Thousands of factories in Japan responded to a survey on power outage costs for industrial customers. From across the country, 5139 facilities designated as energy management factories answered questions about their power consumption and the loss of production value due to a hypothetical hour‐long power outage on a summer weekday. Using their responses, we estimated the median unit cost of a power outage across all sectors to be 672 yen/kWh. The service sector of amusement and hobbies and the manufacturing sector that makes electronic information and communication equipment have relatively high unit costs for power outages. The direct cost of damage from a specified power outage across all sectors totaled 77 billion yen. Using input–output analysis, we estimated the indirect damage costs caused by the repercussions of halting production. Indirect damages across all sectors totaled 91 billion yen. The wholesale and retail trade sector had the largest direct damage costs, while the transportation equipment manufacturing sector has the largest indirect damage costs. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(4): 25–32, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22306     

A study of the buying price of photovoltaic electricity under a carbon tax regime

Assuming that photovoltaic (PV) systems are adopted in residential houses under a carbon tax regime, the economic performance of PV systems is investigated from the standpoint of an electric utility. The economic performance is estimated by using the buying price of PV electricity and the PV economic index, which is defined as the ratio of the buying price to the generation cost of the electric utility. Because these values depend on electric power development and operation, the best mix and the operation of power plants are obtained by linear programming subject to restrictions on power generation. Then, the buying price of PV electricity is calculated from the total cost of the electric utility. The buying price means the upper limit at which the electric utility never suffers a loss. The buying price is also compared with the power generation cost. The parameters are the prevalence attainment ratio of PV systems (0 to 100%), the upper limit of newly developed nuclear power plants (0 to 4 GW/10 y), and the generated energy ratio of coal‐fired thermal plants (0 to 15%). Chubu Electric Power Company, Inc. is used as the electric utility. The calculation results show that the buying price of PV electricity increases linearly with increasing carbon tax rate, and its values are 9 and 11.5 yen/kWh when the carbon tax rate is 0 and 25 thousand yen/t‐C, respectively, which does not depend on the prevalence attainment ratio of PV systems and the upper limit of newly developed nuclear power plants. It is not the carbon tax rate but the newly developed nuclear power plant that influences the PV economic index. The values of the PV economic index are 1.35 to 1.45 and 1.50 to 1.60 when the newly developed nuclear power plant capacity is 0 and 4 GW/10 y, respectively. These results show that the economic performance of PV systems is increased by developing nuclear power plants at a certain rate and introducing a carbon tax. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(2): 38–49, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10067     

Modified multiobjective particle swarm optimization method and its application to energy management system for factories

Conventional energy management systems (EMS) for factories have been developed to minimize energy costs. However, we have to reduce energy consumption and CO₂ emissions to preserve the environment. This paper proposes a multiobjective optimization method based on particle swarm optimization (PSO) to minimize energy costs and CO₂ emissions, and presents its effectiveness through simulation results. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(4): 33–42, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20269     

Optimal daily operation of electric power systems with an ACC‐CAES generating system

Recently, an ACC‐CAES generating system has been developed by applying ACC (Advanced Combined Cycle) technology to a conventional CAES (Compressed Air Energy Storage) system. The ACC‐CAES has a potential advantage of high efficiency and high capacity factor over other energy storage. However, its advantages from the viewpoints of power system operation are not fully revealed because of its peculiar operation characteristics compared with other energy storage. The characteristics include (1) it requires fossil fuel even in the case of operation using stored compressed air and (2) it has an ACC generating mode as one of its generating states to be used as a conventional ACC generating system while detaching the air storage system. Therefore, it is necessary to examine operation patterns of the ACC‐CAES and its contribution to economic operation of a power system. In order to achieve the objective, operation simulations of a power system with ACC‐CAES generating systems are needed because operation of energy storage systems such as the ACC‐CAES must be studied through an operation scheduling of a power system. This paper develops an optimal daily scheduling method of a power system with both ACC‐CAES generating systems and pumped hydro storage systems using two‐dimensional dynamic programming. Sensitivity analyses are undertaken with the developed method; the results show that ACC‐CAES generating systems tend to be operated as a peak or intermediate power source that bears some similarities to thermal plants or storage systems and, from an operation point of view, they have an economic advantage over pumped hydro storage systems. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(1): 15–23, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20087     

Optimization of the electric power leveling system by using superconducting magnetic energy storage with genetic algorithm

A new optimization method of the electric power leveling system using an SMES is proposed. The SMES is parallelly connected with rolling mills in steel works. The leveling control is based on fuzzy reasoning. The SMES capacity and the scaling factors of the fuzzy controller will be optimized so that the power leveling control can be achieved and then the total cost of the added SMES cost and reduced contract electricity rate becomes lower. The optimization is carried out using a genetic algorithm and a cost reduction of 7.76 billion yen can be achieved. Power leveling simulation confirms that the proposed optimization method is very effective for designing the power leveling system. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(3): 62–69, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20049     

A method of estimating energy saving effect and its application to factory energy supply systems

In order to carry out energy saving service, it is indispensable to calculate the energy saving effect quantitatively by presuming the energy cost at the time of not executing the energy saving measure. However, it is difficult because the energy cost changes when environment (energy demand, unit prices of fuel or electric power, and so on) changes even if an energy saving measure is not executed. Although the effect has been conventionally evaluated by the difference between the energy costs before and after the energy saving measure, the effect cannot be calculated correctly when there is environmental change. In this paper, we propose the method of estimating the energy saving effect by presuming the energy cost after an energy saving measure, assuming that the measure is not executed, and show the results of its application to the practical power plants. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(4): 14–20, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20880     

A method for load frequency control using battery in power system with highly penetrated photovoltaic generation

It is generally believed that large battery systems will be needed to store surplus electric energy due to the high penetration of renewable energy (RE) such as photovoltaic generation (PV). Since the main objective of high penetration of RE is to reduce CO₂ emissions, reducing kWh output of thermal generation that emits large amounts of CO₂ in power systems should be sufficiently considered. However, thermal generation plays an important role in load frequency control (LFC) of power systems. Therefore, if LFC could be performed with batteries and hydropower generation, the kWh output of thermal generation could be reduced significantly. This paper presents a method of LFC using batteries in a power system with highly penetrated PVs. An assessment of the effect of the proposed method considering mutual smoothing effect of highly penetrated PVs is made. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(4): 22–31, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22425     

Potential evaluation of energy supply system in grid power system,commercial, and residential sectors by minimizing energy cost

If the economic activity in the commercial and residential sector continues to grow, improvements in energy conversion efficiencies of energy supply systems is necessary for CO₂ mitigation. In recent years, the electricity driven hot water heat pump (EDHP) and the solar photovoltaic (PV) have been commercialized. The fuel cell (FC) of co‐generation system (CGS) for the commercial and residential sector will be commercialized in the future. Copyright © 2004 Wiley Periodicals, Inc. The aim is to indicate the ideal energy supply system of the users sector, which manages both the economical cost and CO₂ mitigation, considering the grid power system. In this paper, cooperative Japanese energy supply systems are modeled by linear programming. It includes the grid power system and energy system of five commercial sectors and a residential sector. The demands of sectors are given by the objective term for 2005 to 2025. Twenty‐four‐hour load for each three annual seasons are considered. The energy systems are simulated to minimize the total cost of energy supply, and to mitigate the CO₂ discharge. As a result, the ideal energy system at 2025 is shown. The CGS capacity grows to 30% (62 GW) of the total power system, and the EDHP capacity is 26 GW, in commercial and residential sectors. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(2): 9–19, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.20361     

A new variable‐speed,constant‐frequency,stand‐alone power generating system

Variable‐speed and constant‐frequency power generating systems using rotor excitation of the wound‐rotor induction machines have been used for such applications as variable‐speed pump generators and flywheel energy storage systems. However, the stand‐alone generating system of this type has only been reported and has not yet been practically used. On the other hand, the stand‐alone generating systems using diesel engines have been widely used for emergency supplies of plants or isolated islands and so on. However, in these cases, synchronous generators are usually used. If the output frequency is to be kept constant, there is the need to control the speed of the engine using a high‐performance governor. Even then, the output frequency changes in the case of a sudden load change. This paper proposes a new stand‐alone power generating system. In this system, the constant‐frequency output voltage can be obtained even though rotor speed changes by several percent. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 75–85, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10191     

Evaluation of cost and reliability of power systems with large numbers of distributed generators

The authors have proposed the Flexible, Reliable and Intelligent ENergy Delivery System (called “FRIENDS”), which is a new concept for future power distribution systems. Also, a “micro grid” which is a similar concept to FRIENDS has been developed. In a micro grid, an independent distribution system can be constituted by a number of distributed generators. In this paper, FRIENDS, Micro grid, and conventional distribution systems are compared quantitatively in supply reliability and system cost through time sequential Monte Carlo simulations. In addition, for cost evaluation, interruption costs are included to show risk incurred by unsupplied energy. Finally, the authors search for preferable form with install and operation of distributed generators and network composition according to social cost including interruption cost and system cost. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 28–37, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20659     

A feasibility study of pressure‐retarded osmosis power generation system based on measuring permeation volume using reverse osmosis membrane

A pressure‐retarded osmosis (PRO) power generation system is a hydroelectric power system which utilizes permeation flow through a semipermeable membrane. Permeation flow is generated by the potential energy of the salinity difference between sea water and fresh water. Since the cost of the membrane is high, the permeation performance of the membrane must be improved in order to realize PRO systems. We have investigated reverse osmosis (RO) membrane products as semipermeable membranes and measured the permeation volume of a few products. The generation power per unit membrane area calculated from the permeation volume is about 0.62 W/m². But as a result of our improvements (greater salt water volume, spacers for fresh water channel with the function of discharging concentrated salinity, extralow‐pressure type of membrane, washing the support layer of membrane when the generation power falls by half) the generated power may be 2.43 W/m². Then the power system cost would be about 4.1 million yen/kW. In addition, if the support layer of the membrane is made thinner and a PRO system is applied to equipment where pumping power for another purpose is available (wastewater treatment plants located at the seaside, thermal and nuclear power plants, sea water desalination plants), the generated power may be increased. These improvements may enable PRO systems to be realized at a cost close to that of photovoltaic power systems. 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(2): 8–20, 2010; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.21000     

Analysis of possible introduction of PV systems considering output power fluctuations and battery technology,employing an optimal power generation mix model

This paper presents an evaluation of the impact of extensive introduction of photovoltaic (PV) systems and stationary battery technology into the optimal power generation mix in the Kanto and Kinki regions. The introduction of solar PV systems is expected to be extensively deployed in the Japanese household sector and utility companies in order to address the concerns of energy security and climate change. Considering this expected large‐scale deployment of PV systems in electric power systems, it is necessary to investigate the optimal power generation mix which is technologically capable of controlling and accommodating the intermittent output‐power fluctuations inherent in PV systems. Against this background, we develop both a solar photovoltaic power generation model and an optimal power generation mix model, including stationary battery technology, which can be used to explicitly analyze the impact of PV output fluctuations at a detailed time interval resolution such as 10 minutes for 365 consecutive days. Simulation results reveal that PV introduction does not necessarily increase battery technology due to the cost competitiveness of thermal power plants in the load‐following requirement caused by PV systems. Additionally, on the basis of sensitivity analysis on PV system cost, dramatic cost reduction proves to be indispensable for PV to supply bulk electricity similarly to thermal and nuclear power plants. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(2): 9–19, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22329     

用成本矩阵算法分析热电厂热电成本

通过修改火电机组热力系统成本分布通用矩阵模型,建立了抽凝机组成本分布通用矩阵模型,并将其应用于热电厂热电成本分摊。对某300 MW单抽机组的热力系统进行了实例计算,并将计算结果与其他几种分摊方法所得结果进行了对比分析。结果表明：与以往的热电分摊方法相比,本方法采用的矩阵形式简单方便,以系统工程的观点来追踪能量生产过程以及成本形成过程,能够反映热电厂真实的热、电成本。另外,还定量分析了某300 MW双抽机组在不同抽汽工况下的热、电成本。结果表明,该机组在有抽汽的工况下的发电燃料成本比纯凝汽工况下的成本低大约0.03～0.04元/kW＆#183;h左右。随着工业抽汽量或采暖抽汽量的增加,该机组的发电、供热及工业抽汽的燃料成本均降低。     

Forecasting electric power generation in a photovoltaic power system for an energy network

Recently, there has been an increase in concern about the global environment. Interest is growing in developing an energy network by which new energy systems such as photovoltaic and fuel cells generate power locally and electrical power and heat are controlled with a communication network. We developed the power generation forecast method for photovoltaic power systems in an energy network. The method makes use of weather information and regression analysis. We carried out forecasting power output of the photovoltaic power system installed in Expo 2005, Aichi Japan. As a result of comparing measurements with prediction values, the average prediction error per day was about 26% of the measured power. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(4): 16–23, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20755     

Compensation of power fluctuations of wind power generation by means of biomass gas turbine generator and flywheel energy storage equipment

Power generation using natural energy contains electric power fluctuations. Therefore, in order to put such power generation systems to practical use, compensation for system power fluctuations is needed. In this paper, we propose a power compensation method using a biomass gas turbine generator and flywheel energy storage equipment. The gas turbine generator is used for compensation of low‐frequency power fluctuations in order to decrease the required flywheel capacity. The usefulness of the proposed system is confirmed by experiments using a test plant. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 1–8, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20896     

A Two‐Stage Stochastic Mixed‐Integer Programming Approach to the Smart House Scheduling Problem

A “smart house” is a highly energy‐optimized house equipped with photovoltaic (PV) systems, electric battery systems, fuel cell (FC) cogeneration systems, electric vehicles (EVs), and so on. Smart houses are attracting much attention recently because of their enhanced ability to save energy by making full use of renewable energy and by achieving power grid stability despite an increased power draw for installed PV systems. Yet running a smart house's power system, with its multiple power sources and power storages, is no simple task. In this paper, we consider the problem of power scheduling for a smart house with a PV system, an FC cogeneration system, and an EV. We formulate the problem as a mixed‐integer programming problem, and then extend it to a stochastic programming problem involving recourse costs to cope with uncertain electricity demand, heat demand, and PV power generation. Using our method, we seek to achieve the optimal power schedule running at the minimum expected operation cost. We present some results of numerical experiments with data on real‐life demands and PV power generation to show the effectiveness of our method. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 48–58, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22336     

生物质气化发电技术现状

简要介绍生物质能的特点和生物质气化发电技术的原理及国外研究现状,着重介绍了TPS的整体气化联合循环发电系统和Battelle生物质气化发电系统。指出在我国应该大力发展生物质气化发电技术。     

发电侧备用电池储能系统的技术经济分析

储能电池具有ms级的响应速度,能够快速平衡随时变化的负荷波动,可以作为火电厂的容量备用电源。但是,电池储能系统高昂的成本是阻碍其商业应用的重要原因之一。以锂离子电池、钠硫电池、全钒液流电池为例,采用成本收益分析方法,研究了其作为火电厂容量备用电源的技术经济性能。研究结果表明：尽管这3种储能电池的功率成本和能量成本较高,若将其作为火电厂容量备用电源,在其寿命周期内仍然可以获得较好的经济效益,收回成本年限远小于其寿命周期。通过电池储能系统的容量备用,可以提高火电厂的发电负荷率,降低发电煤耗,不但降低发电成本,而且减少燃煤电厂的CO2和污染物排放,从而起到节能减排的作用。     

Electron spectroscopy of organic thin‐film FETs

Organic thin‐film FETs have been studied by using electron spectroscopic techniques. Ultraviolet photoelectron spectroscopy has revealed that photopolymerization is enhanced by fabricating FET structure. Energy levels and the effective mass of charge carriers are discussed based on the results of photoelectron spectroscopy and electron energy loss spectroscopy. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(1): 31–36, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20154