In this paper, the author describes the historical development of the energy related researches briefly and then introduces how this area has been affected by the social circumstances. Since the oil crisises in 1973 and 1978, energy conservation has been the key factor as well as the “deregulation” of the market. These two factors shifted the energy supply-demand structure from one-way flow to the birateral network involving multiple players. System methods such as gamie theory and multi agent systems are introduced to see how the energy market behaves. New transmission and distribution system is proposed to establish the flexible and reliable power system. When we look into the regional energy and environmental issues, the policy maker has to solve the interactions among energy technologies, waste management and utilization technologies and transportaion systems. The system engineering methods have to provide the solution in such an interdisplinary area.
Abatement of CO2 emission is one of the most important issues for us in the 21st century about preservation of the earth environment. This paper addresses a utility operations planning problem for distributed energy management systems (DEMSs), where we are to obtain optimal plans that minimize both of costs and CO2 emissions. A DEMS consists of plural entities that seek their own economic profits. In this paper, we give a mathematical formulation of the utility operations planning problem for each entity, and propose an energy trading market, which utilizes a multi-attribute auction protocol in order to deal with both of a price and a CO2 emission rate. Experimental results show that collaboration among entities through the market provides more profitable plan for each entity and abatement of CO2 emission is also achieved.
It is said that the cogeneration system(CGS) and Heat pump system(HP) are effective air conditioning systems for energy saving and CO2 reduction in the commercial building. However, the economic, energy and environmental efficiency characteristics of these systems vary so much depending on the weather conditions and the demand patterns of heat and electric power. In this research, we develop a model to evaluate the optimum capacity and the operating patterns of air conditioning system by nonlinear mixed integer programming in order to formulate the partial load properties of heating equipments in practical operation. Since our model involves the estimation procedure of energy load of the building based on the human density and the structure of that, it enables us to evaluate the optimum condition of tenants from the air conditioning demands. The compatibility between the economy and the energy saving of the air conditioning system implementation planning has been the problem. We propose a new measure to develop an optimal energy saving system under the constraint of the investment recovery years as economic efficiency for the commercial building. The results show us that the optimum planning depends on the regional weather conditions as well as energy equipments and energy load patterns.
This paper discusses the potential of DEA (Data Envelopment Analysis) for performance evaluation on domestic energy consumption. The purpose is to develop evaluation methodology for diversification of energy provision and consumption. From four evaluation measures (economy, environment, comfortability and risk), this paper focuses economical and environmental aspects, and selects energy consumption, CO2 discharge and cost as inputs for the first step model. In order to consider the evaluation methodology based on the practical data, this paper has focused on hot-water supply as output of the model. Then the numerical study for four monitor homes illustrates four kinds of findings. This paper also compares our DEA-based analysis with the traditional regression model based analysis, and implies the future research.
Wind power has recently become quite popular among power generation companies all over the world. In the year 2003 alone 8,133MW of new installations have been built up. When integrating these huge amount of wind power into an existing power grid and the trading process of a power utility on the electricity market, the uncertainty in wind power generation becomes a critical point. There are basically two viewpoints on this issue. First, operating wind power generation in a power grid needs a high amount of regulation reserve. Therefore wind generation is expensive. On the other hand, wind power generation does not consume fuel and therefore there are no fuel cost. To estimate the consequences of high wind power generation we propose in this paper a simulation model that is capable of simulating spot and ancillary markets, as well as the physical aspects of electricity generation. By simulating the interaction between spot and ancillary market we calculate the development of the electricity prices on the spot market and the ancillary market with growing wind power generation.
We made a mathematical model of the Japanese economy using a macro-economic modeling framework called a Computable General Equilibrium model. We used the model to estimate the impacts of the progress of ubiquitous technologies on the CO2 emissions in Japan. We made 4 scenarios on the ubiquitous society in Japan in 2010. The 4 scenarios correspond to 4 different levels of the progress of ubiquitous society. In each scenario, we assumed electricity consumption by electronics products, effects of ubiquitous applications on energy use, and the market size of ubiquitous application services. The results indicate that advanced ubiquitous technologies would potentially reduce the CO2 emissions of the Japanese economy by 2.8%.
Toward a sustainable society, energy and environmental issues are very important and controversial problems, and it is expected to support various human activities for the measures by using Information Technology. The purpose of this study is to develop an affective interface for supporting people's energy-saving activities. First, a model for supporting people's energy-saving activities involving affective elements has been constructed for supporting people's energy-saving activities, based on social psychological approaches. Based on the proposed model, the requirements on an affective interface for people's energy-saving activities have been considered. In this study, the affective interface presents suitable energy-saving activities and current electric energy consumption by a character agent with a graphical shape and synthesized voice. The character agent recommends people's energy-saving activities, tells the method of energy-saving activities and the effectiveness, and so on. The affective interface for supporting energy-saving activities has been designed in detail and developed. Then, the evaluation experiment of the developed interface has been conducted, and the results of the experiments were analyzed.
A pay-as-bid auction has been adopted in a balancing market under New Electricity Trading Arrangements in England and Wales since 2001 instead of a uniform price auction previously used in a day-ahead pool market. In contrast, a spot market in Japan, where a general electric utility would be the main supplier, plans to employ a uniform price auction. In this paper we model an electricity spot market in which one large generator competes with many fringe generators to supply electricity, analyze how this large generator bids to maximize its profits, and report some implication for the design of this market. Three types of auction are analyzed: a highest-winning-bid pricing (HWB) uniform price auction, a lowest-losing-bid pricing (LLB) uniform price auction and a pay-as-bid auction. It is shown that the slope of the bid curve, which is obtained by plotting the large generator's bidding prices against its generation costs, are steeper in an LLB uniform price auction and flatter in a pay-as-bid auction than those in an HWB uniform price auction. This implies that an LLB uniform price auction or a pay-as-bid auction would make room for the fringe generators to win an auction.
Although various energy system alternatives for business, commercial and residential customers have been recently developed in order to reduce energy consumption and CO2 emission, it is important to evaluate competitive characteristics among such new energy system alternatives quantitatively, in consideration of tradeoff relation among economic cost, energy consumption and CO2 emission. In this paper, using multi-objective optimization model for urban energy system planning, two competitive evaluations are performed. One is the break-even cost analysis for introducing more efficient, but more expensive energy equipment, such as photovoltaic system and fuel cell system. The other is that we evaluate the competitiveness of a certain energy system from a viewpoint of whole urban area because there are multiple alternatives for attaining same target of reducing CO2 emission or energy consumption.
For the effective utilization of municipal solid waste (MSW) through a thermal recycling, new technologies, such as an incineration plant using a Molten Carbonate Fuel Cell (MCFC), are being developed. The impact of new technologies should be evaluated statistically for various municipalities, so that the target of technological development or potential cost reduction due to the increased cumulative number of installed system can be discussed. For this purpose, we developed a model for discussing the impact of new technologies, where a statistical mesh data set was utilized to estimate the heat demand around the incineration plant. This paper examines a case study by using a developed model, where a conventional type and a MCFC type MSW incineration plant is compared in terms of the reduction in primary energy and the revenue by both electricity and heat supply. Based on the difference in annual revenue, we calculate the allowable investment in MCFC-type MSW incineration plant in addition to conventional plant. The results suggest that allowable investment can be about 30 millions yen/(t/day) in small municipalities, while it is only 10 millions yen/(t/day) in large municipalities. The sensitive analysis shows the model can be useful for discussing the difference of impact of material recycling of plastics on thermal recycling technologies.
By considering change in energy transmission infrastructures, this paper describes a comparative assessment of energy systems with distributed generators such as a co-generation system (CGS). Material use measured by weight is used as an index for characterizing both technical and economical features of energy apparatuses. For various CGS penetration ratio (0%-100%), we evaluate the influence of CGS on overall weight and efficiency of energy systems. Depending on the CGS penetration ratio, we estimate the energy transmission infrastructure, i.e. electricity transmission lines and gas pipelines, by appropriately choosing voltage class or pipe size, and parallel number for minimizing the total weight. While the installation of CGS increases a peak demand of city gas on the whole, it may not reduce a peak demand of electricity because most CGS may not be operated during the summer season with very small hot-water demand, resulting in small contribution to reduction in electricity transmission infrastructures. In addition, because of relatively larger unit weight of CGS than that of large-scale power plants, the total weight of energy system increases with increasing CGS penetration ratio, while energy efficiency of the total system is increased also. The results suggest that individual CGS should be operated to avoid the installation of additional material use for gas transmission infrastructures for developing environmentally friendly energy systems.
In this paper we propose a new type of comb-line filter which consists of a couple of meander-shaped quarter-wavelength microstrip resonators. We investigate the filtering characteristics through FD-TD simulations. Furthermore, we design the filter and discuss its filtering characteristics through experiments as well as numerical simulations. It is found that this filter realizes a considerable reduction in the size of structure and sharp bandpass characteristics with multiple attenuation poles around the passband.
The proposed Ring Network with VLAN Tag offers the features of wrapping/steering control functions and 1+1 path protection function, keeping the compatibility with Ethernet media access control scheme. The key technology for “Path concept” is VLAN tag swapping operation. A set of primary and back-up paths is defined between ring nodes, which are distinguished by a flag bit in VLAN tag field. On failure detection, the path is switched within the path set by the tag swapping. Tag swapping at the failure detection node, while tag swapping at the source node achieves staring operation, achieves Wrapping operation. The restoration behavior is almost the same as that of Resilient Packet Ring (RPR). Since the tag swapping control is based on hardware processing, high-speed operation is also expected. Furthermore, because the paths are independently designed from the physical topology, the scheme can be applied to other networks than physical ring networks. The proposed scheme will fit to the path control for next generation Ethernet over WDM system.
A 10-GHz clock signal is successfully extracted from a 160-Gbit/s optical RZ signal using devices operable up to 40 GHz. The down-conversion of the 160-Gbit/s input signal into 40 Gbit/s signal is performed by modulating the input optical signal by an LN modulator that is driven by a RF signal with an amplitude of 3Vπ and a frequency of 40 GHz. Extraction of 10-GHz clock from the down-converted signal is done by an injection locking technique. An electrical PLL circuit is also examined for a reference. Regarding the recovered clock, basic properties of hold-in frequency range, frequency response, and phase jitter are found to be satisfactory. The faultlessness of the extracted clock signal was confirmed by bit error rate measurements.
This paper discusses a new combinatorial optimization problem which occurs in line balancing for real assembly lines demanding skilled operations. On the contrast with conventional assembly lines such as automotive in which each operation is associated with a standard processing time, it is assumed that each operation time depends on assigned worker's skill and there exists an upper bound on the number of operations to be assigned to each worker. Three genetic algorithms (GAs) which have different genotypes and different decoding procedures are discussed for this problem. The genotype in the first GA is expressed by sequencing the operation numbers, and an effective heuristic rule is introduced into the decoding procedure. In the second GA, the genotype is expressed by sequencing the sets of operations to be assigned to each worker. In the third GA, the genotype is expressed by sequencing the worker numbers executing each operation in the order of operation numbers. These GAs are compared by numerical experiment based on real conditions.
Some visually impaired children have difficulty in simple locomotion, and need orientation and mobility training. We developed a computer assisted instruction system which assists this training. A user realizes a task given by a tactile map and synthesized speech. The user walks around a room according to the task. The system gives the gap of walk path from its target path via both auditory and tactile feedback after the end of a task. Then the user can understand how well the user walked. We describe the detail of the proposed system and task, and the experimental result with three visually impaired children.
Existing algorithms such as ASelite and ASrankRS do not work well for Graph Coloring Problem (GCP) due to local search performance of each ant. This paper proposes Queen Ant Strategy for GCP which controls search intensification and diversification and makes it easier to implement in parallel than the existing algorithms.