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This paper provides the theoretical calculation results of thermodynamic and transport properties of CO2, CO2–O2 mixture, CO2–H2 mixture under thermal equilibrium condition at temperatures of 300 to 30,000 K and at pressures of 0.1 to 10 MPa. The gas CO2 is one of the candidates for the environmentally benign arc-quenching medium in a circuit breaker. Furthermore, the effect of additional gases O2 and H2 on the thermodynamic and transport properties of CO2 was also investigated in this paper. The hydrogen atom included CO2 is similar to the polymer ablated vapor in switching devices. First, equilibrium compositions of CO2, CO2–O2 mixture, CO2–H2 mixture were calculated through the Gibbs free energy minimization method. Second, thermodynamic properties were computed using the calculated composition. Finally, transport properties were calculated by the first-order approximation of Chapman– Enskog method using the collision integrals between species. Inclusion of H2 increases the electrical conductivity of CO2 in the range 3000 to 6000 K because CHO molecules produced in this temperature range emit more electrons due to the lower ionization potential of CHO. It also increases the thermal conductivity of CO2 especially due to dissociation reactions of H2 around 3900 K and ionization of H around 15,000 K. These properties provided here can be used for CO2 thermal plasma simulation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(4): 18–29, 2008; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20467 [ABSTRACT FROM AUTHOR]

Abatement of CO2 emission is one of the most important issues in the 21st century regarding 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 costs and CO2 emissions. A DEMS consists of multiple 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 utlizes a multi-attribute auction protocol in order to deal with both a price and a CO2 emission rate. Experimental results show that collaboration among entities through the market provides a more profitable plan for each entity and abatement of CO2 emission is also achieved. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 54–63, 2008; Published online in Wiley InterScience (www.interscience.wiley. com). DOI 10.1002/eej.20418 [ABSTRACT FROM AUTHOR]

This Paper presents an efficient computational algorithm for selecting the optimal generation mix considering CO 2 emission. To demonstrate the effectiveness and feasibility of the proposed method, a fundamental study of the evaluation of the optimal generation mix for controlling CO2 emissions is indicated, Futhermore, by using parametric analysis which considers load characteristics as parameters, a general trend for the optimal generation mix which is affected by controlling CO2 can be derived. The proposed method is based on an optimization method know as simulated. In the method, solution in a generation mix problems are equivalent to states of physical system, and the cost of a solution is equivalent to a state. The proposed method can easily accommodate not only CO2 emission but also many practical constrains of generation expansion planning, such interger solutions of unit capacities, condition of existing units, and so on. Case studies various annual load patterns (combinations of annual factors and the shapes of annual load duration curve) are presented and discussed. Consequently, a general trent for selecting generation technologies that should be added to a power system is derived, i.e., a useful guideline for studying generation expansion planning under controlling CO2 emission can be provided. [ABSTRACT FROM AUTHOR]

This paper considers the effectiveness of the service business approach for reducing CO2 emissions. 'HDRIVE' is a service business using inverters to reduce the energy consumption of motor drive. The business model of this service is changed to find new opportunities of CO2 emission reduction by combining various factors such as financial services or long-term service contracts. Risk analysis of this business model is very important for providing stable services to users over the long term. The HDRIVE business model is found to be suitable for this objective. This service can be applied effectively to industries such as chemicals or steel, where CO2 emissions are very large, and has the possibility of creating new business considering CDM or trading CO2 emission rights. The effectiveness of this approach is demonstrated through several examples in real business. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(3): 40-48, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21242 [ABSTRACT FROM AUTHOR]

This paper proposes a novel method based on real options theory for economic evaluation of the replacement of an old coal-fired thermal power plant (COAL) with a coal-fired thermal power plant that includes a CCS (carbon dioxide capture and storage) unit. We calculate the real option value (ROV) of CCS as the value of an American call option with dividend, treating the increased carbon cost of COAL due to the delay of replacement as opportunity cost. The appropriate construction time of a CCS unit is evaluated by binominal decision tree analysis for option exercise. We calculate the change of project ROV and the appropriate construction time according to the difference in carbon emission benchmarks and the variation of the maintenance cost of COAL. The effect of power station lifetime is also analyzed. We conclude that flexibility in the timing of decision making increases the value of a project. We also found that CCS is an economically justifiable technology option under forthcoming restrictions on carbon emissions. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(3): 9-17, 2011; Published online in Wiley Online Library (). DOI 10.1002/eej.21065 [ABSTRACT FROM AUTHOR]

Possible designs for a self-sufficient residential binary solar energy include a side-by-side system, a PVT hybrid system, and a side-by-side PVT hybrid system. We designed and performed an annual performance simulation of three systems: PV with flat plate collector (PV/FPC), photovoltaic-thermal hybrid (PVT), and PV with photovoltaic-thermal hybrid (PV/PVT) including an electrical auxiliary heat pump. In this paper, the solar energy fraction (SEF) or auxiliary energy fraction (AUX) is used as a figure of merit for system evaluation. These indices are shown to be affected by the COP (coefficient of performance) of AUX and by the ratio of the DHW (domestic hot water) load to the annual synthetic load. The best results were achieved by the side-by-side PV/PVT hybrid system. Using PVT with PV leads to an improvement of the SEF or AEF compared with the PVT system alone. Glazing is found to be indispensable for the PV/PVT system with an AUX COP of 1, but is unnecessary for a PV/PVT system with a higher COP. © 2001 Scripta Technica, Electr Eng Jpn, 137(1): 28–35, 2001 [ABSTRACT FROM AUTHOR]

This paper describes the characteristics and construction of a coal-gas-burned high efficiency power plant which emits no carbon dioxide (CO2) into the atmosphere. In a plant, CO2 gas and superheated steam are used as the main and the secondary working fluids, respectively, of a closed dual fluid regenerative gas turbine power plant. Since coal gas composed of CO, H2, CO2 and CH4 is burned in a combustor using oxygen, the exhaust gas let into a condenser includes only CO2 and H2O. Hence, CO2 gas can be easily separated at the condenser outlet from condensate. In the plant, the combustion gas is first used to generate power by driving a turbine. High-temperature turbine exhaust gas is next utilized at a regenerator to heat the main working fluid of CO2 gas flowing into the combustor, and then is utilized at a waste heat boiler to produce the superheated steam injected into the combustor. It is estimated that the power can be generated with gross thermal efficiency of 54.4 percent, and that the power generating efficiency is 46.7 percent. Generating efficiency is calculated by subtracting the power required for producing the high-pressure oxygen used for combustion from the generator output. It is shown that the estimated efficiency is higher by 18.1 percent than that of a conventional boiler steam turbine power generating plant into which a process for removing and recovering CO2 from the stack gas by utilizing alkanolamine-based solvent is integrated. [ABSTRACT FROM AUTHOR]

SUMMARY This paper investigates the impact of an extensive introduction of electric vehicles ( EV) and plug-in hybrid vehicles ( PHEV) into the global energy system by 2050. The significant growth of automobile ownership in emerging countries is likely to increase world oil demand and the associated carbon dioxide emissions. In order to address these energy, security, and environmental concerns, the deployment of clean energy vehicles, such as EV and PHEV, is expected to play a crucial role due to their high fuel efficiency. Consequently, we develop both a global energy system model and a world vehicle penetration model, which can explicitly analyze the impact of EV introduction into the seasonal daily electric load curve, with consideration of the specific electricity charging profile through 2050. The simulation results confirm that EV deployment contributes to energy conservation, because oil demand reduction outstrips the growth in electricity demand and the associated fuel input into the power generation mix. Concerning carbon dioxide abatement, the magnitude of the impact relies on the carbon intensity of the power generation mix. If the intensity is low enough to guarantee a carbon mitigation effect due to EV fuel saving, emissions reduction is well assured. It should be noted, however, that in regions with high carbon intensity in the power generation mix, carbon emissions per mileage of EVs is almost equivalent to that of efficient gasoline vehicles such as hybrid vehicles, and the figure for PHEV is slightly higher than for hybrid vehicles. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 20-36, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22373 [ABSTRACT FROM AUTHOR]

Global warming due to increasing atmospheric carbon dioxide (CO2) is a matter of serious concern. Energy efficiency improvement has been considered to be the most effective strategy for reducing CO2 emissions. The acceleration of R&D for energy technologies which have large effects on CO2 emission reduction should be effective in abating global warming. In this study, the author proposes a method for evaluating the effects of energy efficiency improvement on CO2 emission reduction. This method utilizes a compact energy system model combined with analytical calculations. Using this method, effects of energy efficiency improvement in Japan in the year 2030 are analyzed. Energy efficiency improvement in thermal power generation, nuclear power generation, and heat utilization are especially effective for reducing CO2 emissions. The author estimates that CO2 emissions per capita can be stabilized at the present level by energy efficiency improvement. [ABSTRACT FROM AUTHOR]

Osaka Gas Co., Ltd., jointly with NTT DATA Mathematical Systems Inc., has developed unit‐commitment model for optimizing dispatch of power generation units. Main purpose of this development is to simulate the future world of electric power system in accordance with national energy policy aiming to introduce large amount of renewable energy as well as vitalized cross‐border power exchange via PX market to enhance economically‐efficient power system operation. The model incorporates not only constraints of supply‐demand balance but also constraints of operating reserves, regulation reserves, maximum CO2‐emissions, etc. [ABSTRACT FROM AUTHOR]

First, current interrupting experiments were performed for a rotary-arc type of load-break switch filled with pure CO2 at a total pressure of 0.1 MPa. Increase in the coil turns for generating magnetic field from 1 to 1.8, 2.5, and 3.6 (arbitrary unit) raised the current interrupting capability from 2.6 kA to 3.2, 3.5, and 4.1 kA. Second, experiments were performed for CO2 gas mixture under the condition of 3.6 coil turns. Gases of He, O2, N2, and air were admixted to CO2. Adding either He or O2 to CO2 at a concentration of 30% allows the switch to have higher interrupting capability than using pure CO2. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 21–27, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20742 [ABSTRACT FROM AUTHOR]

The authors recently proposed a high-performance combined carbon-dioxide-capturing power generation system using a solid oxide fuel cell (SOFC) and a closed-cycle MHD generator, in which pure oxygen is used as the oxidant. This combined system makes the best use of the advantages of combustion with pure oxygen but fails to prevent the efficiency deterioration caused by high power demand for oxygen production. In the present study, the authors modified this previous system and proposed an improved combined carbon-dioxide-capturing power generation system using SOFC/MHD characterized by a higher overall thermal efficiency. In this system, pure oxygen is supplied only to the combustor to reduce the power required for the oxygen production, and pressurized air is used as the oxidant gas in the SOFC. The power saving amounts to about 5% of the thermal input, resulting in a very high total thermal efficiency of 67.53% (HHV) or 74.94% (LHV), which is considered to be the highest possible value of the overall thermal efficiency of carbon-dioxide-capturing systems. Advantages of the proposed system suggest that it is advisable to continue further research in this direction. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 21–30, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20010 [ABSTRACT FROM AUTHOR]

We evaluated total energy consumption and CO2 emissions in the phases of a city gas utilization system from obtaining raw materials to consuming the product. Assuming monthly and hourly demand figures for electricity, heat for space heating, and hot water in a typical hospital, we explore the optimal size and operation of a city gas system that minimizes the life cycle CO2 emissions or total cost. The cost-effectiveness of conventional cogeneration, a solar heating system, and hybrid cogeneration utilizing solar heat is compared. We formulate a problem of mixed integer programming that includes integral parameters that express the state of system devices such as the on/off condition of switches. As a result of optimization, the hybrid cogeneration can reduce annual CO2 emissions by 43% compared with the system without cogeneration. The sensitivity of CO2 reduction and cost to the scale of the CGS is also analyzed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 22–32, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10369 [ABSTRACT FROM AUTHOR]

A new fossil-fuel-utilized high-performance combined power generation system with liquefaction recovery of carbon dioxide is proposed. In the system, pure oxygen is used as the oxidant gas to prevent the mixture of nitrogen in the exhaust gas and to make the liquefaction recovery of carbon dioxide possible. Solid oxide fuel cell is selected as the topping cycle. The exhaust fuel gas of the solid oxide fuel cell is afterburned with its exhaust oxidant gas of pure oxygen and the heat of the combustion gas is utilized in the bottoming cycle. Nonequilibrium MHD/noble gas turbine cycle is selected as the bottoming cycle because the temperature of the combustion gas reaches about 2300 K. It is made clear through detailed examination of energy balance that the total thermal efficiency of the system using natural gas (methane) as the fuel reaches 63.24% (HHV) or 70.18% (LHV). This efficiency is very high as for the system with carbon dioxide recovery. The proposed system, therefore, has excellent performance, and further research and development is warranted. [ABSTRACT FROM AUTHOR]

A CO-recovering hybrid power generation system utilizing thermal energy is proposed. In the system, relatively low temperature saturated steam around 220° is produced by using solar thermal energy and is utilized as the working fluid of a gas turbine in which generated CO 1 id recovered based on the oxygen combustion method. Hence solar thermal utilization efficiency is considerably higher as compared with that of conventional solar thermal power plants in which superheated steam near 400° must be produced for use as the working fluid of steam turbines; the requirement for solar radiation in the location in which the system is constructed can be significantly relaxed. The proposed system is a hybrid energy system using both the fossil fuel and solar thermal energy, thus the capacity factor of the system becomed very high. The fuel can be used exergetically in the system; i.e., it can be utilized for raising the temperature of the steam heated by utilizing the turbine exhaust gas more than 1000° The generated CO2 can be recovered by using oxygen combustion method, so that a high CO2,capturing ration of near 100. percent as well as no thermal NO, emission characteristics can be attained. It is been shown through simulation study that the proposed system has a net power generation efficiency of 63.4 percent, which is higher than 45.7 percent as compared with at that of the conventional power plant with 43.5 percent efficiency, when the amount utilized solar energy is neglected and the temperature of the saturated steam is 220° [ABSTRACT FROM AUTHOR]