著者

古澤 陽 西嶋 瑛世 海野 真穂 堀田 裕弘

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.44, no.3, pp.152-159, 2023-05-10 (Released:2023-05-10)

参考文献数

23

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In Japan, the active introduction of renewable energies is encouraged in order to achieve a decarbonized society. Among renewable energies, photovoltaic power generation, which can be introduced relatively easily in buildings and houses, is being used, and its further introduction is desired. Therefore, there is a need for technology to accurately predict the amount of electricity generated at potential sites for photovoltaic power generation facilities. In this study, we tried various machine learning methods for predicting the amount of electricity generated by photovoltaic power generation without using the information of the solar radiation meters, and examined the effect of the training period of machine learning on the accuracy of the estimation.

著者

西嶋 瑛世 古澤 陽 海野 真穂 堀田 裕弘

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.44, no.3, pp.145-151, 2023-05-10 (Released:2023-05-10)

参考文献数

21

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Since the Paris Agreement in 2015, there has been growing interest in global warming around the world, and accelerated measures to global warming are required to realize a decarbonized society by declaring the goal of carbon neutrality. As one of the measures, Demand Response (DR) are being actively introduced and provided. DR is a system whereby electric power companies pay incentives through transactions to consumers who cooperate in saving electricity during peak periods of electricity demand, thereby reducing peak electricity demand. Electricity demand for individual buildings is easily affected by seasonal fluctuations, the presence or absence of events, and other factors, and the occurrence of electricity demand peaks tends to be irregular, so highly accurate electricity demand forecasting is needed. In this study, we focus on the educational facilities such as University campus. The objective of this study is to use machine learning to construct a highly accurate forecasting model for not only the steady electricity demand in daily life, but also the characteristic electricity demand during events.

著者

山田 洋行

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.43, no.3, pp.103-112, 2022 (Released:2022-05-10)

参考文献数

12

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For expanding the installation of solar power systems in detached houses, it is important to understand the status of power consumption and solar power generation based on their characteristics. Therefore, we surveyed the electricity consumption, PV capacity, power generation, power sales, and self-consumption rate of detached houses in each year of PV installation, using micro data of survey on carbon dioxide emissions from residential sector. The results show that the average capacity of PV installed before 2010 was 3.9 kW, while the capacity of PV installed in 2013-2014 was 5.5 kW, an increase of more than 30%. On the other hand, it was found that the total floor area of houses has not changed that much. Thus the increase in average PV capacity can be attributed to lowered economic constraints such as reduced PV system costs and the popularity of overloading. In addition, there has been no increase in average capacity of PV installed after 2015, which can be due to new constraints related to the location of PV installations, such as the total floor space of houses.

著者

立松 正幹 澤崎 正明 前川 友哉 上田 順一

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.42, no.5, pp.351-356, 2021 (Released:2021-09-10)

参考文献数

8

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Recently, many renewable energy sources are connected to power systems. Renewable energy sources such as PV and wind connected to power systems via inverters are called inverter sources. When the percentage of inverter sources increases, the percentage of synchronous generators such as hydro, thermal and nuclear decreases. When many inverter sources are connected to power systems with small capacity which are not synchronously connected to other power systems, the percentage of synchronous generators significantly decreases. Therefore, influences of power system characteristics such as synchronizing power decrease, power system inertia decrease and short circuit capacity decrease are concerned. And influences of power system stability such as transient stability decrease, frequency and voltage fluctuation increase and distortion level increase are also concerned. Previously, power system inertia estimation and power system stability monitoring were done by off-line. Therefore, on-line power system inertia estimation and power system stability monitoring system is newly developed for the purpose of precise understandings of Japanese Eastern (50Hz) and Western (60Hz) power systems.

著者

古川 慶人 小宮山 涼一 藤井 康正

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.43, no.6, pp.225-234, 2022-11-10 (Released:2022-11-10)

参考文献数

19

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Cryogenic Direct-air CO2 Capture (Cryogenic DAC), the technology of capturing atmospheric CO2 by desublimiting it as dry ice, can effectively utilize the abundant wind energy in Antarctica and it is estimated that the energy requirement will be competitive towards conventional aqueous solution DAC if substantial efficiency improvements and system enhancements occur. However, it hasn’t been implemented yet and the energy requirement and capital cost are uncertain. In this study, the feasibility of cryogenic DAC is analyzed by conducting a sensitivity analysis on the energy requirement/capital cost of cryogenic DAC and the capital cost of wind/solar energy in Antarctica under the 1.5℃/2.0℃ goals in Paris Agreement. As a result, if the capital cost of wind/solar power in Antarctica is the same as in Alaska the energy requirement/capital cost of cryogenic DAC require to be lower than that of aqueous solution DAC for cryogenic DAC introduction in both goals. In addition, when the energy requirement/capital cost of cryogenic DAC are fixed, it is found that the capital cost of wind/solar power generation in Antarctica requires to be limited to about 1.2 times the global standard cost for cryogenic DAC introduction in the 1.5℃ goal.

著者

遠藤 操

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.41, no.6, pp.233-242, 2020 (Released:2020-11-10)

参考文献数

28

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The purpose of this paper is to evaluate the swing option price written on the underlying asset of JEPX spot price. The swing option price is calculated by following three steps; (i) modeling JEPX spot price process taking into account the features of mean-reverting, seasonality and spikes, (ii) deriving risk-neutral measure from TOCOM electricity forward curve, and (iii) executing Least-squares Monte Carlo simulation. The calculation result is shown in several graphs which focus on the combination of swing type, number of swing rights and option exercise price. Moreover, this paper analyzes the sensitivity of swing option price to the spot price trend, volatility and spike frequency. Swing option has already been introduced in power purchase agreements between power generating companies and power retail companies in Japan. Therefore, it is considered important for these companies to find a suitable reference price for negotiation. This paper will show a theoretical way to calculate the reference price.

著者

前田 豊

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.33, no.6, pp.9-14, 2012 (Released:2019-06-06)

参考文献数

12

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The ways of using solar energy for human being are to use solar cells for direct solar ray, or to warm up object by using radiant heat of the sun. However, most of the solar energy which is showered upon the earth is used for the heat-reserve in seawater and the earth. There seems not to have existed in the past that the ways of thinking to utilize heat energy near the normal temperature as the effective work, exergy, which was directly stored up in the earth. This paper presents a new energy source, which is got from room temperature heat source. There exist a new heat cycle that creates exergy from room temperature materials. This is composed of a unique heat cycle of CO2 gas as a heat medium. The mechanism is shown through exergy analysis as to the heat cycle which creates valid work. Proper systems are discussed on generation of electricity, and warm or cold heat, using this cycle.

著者

内田 晋 根本 和宜 杉浦 正吾 下田 邦夫 川廷 昌弘 五十嵐 彰 小坂 潤平 水野谷 剛 氷鉋 揚四郎

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.31, no.3, pp.8-14, 2010 (Released:2019-08-26)

参考文献数

5

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Energy consumption structure of Japanese professional baseball games was analyzed. Multiple linear regression analyses of electricity consumption in stadiums indicated that the length of games, air-conditioning load (calculated from the temperature), starting time of games (day or night) and humidity affected the electricity consumption in most stadiums, and also the number of spectators and atmospheric pressure affected in some stadiums. Total electricity consumption was decomposed to each factors based on the result of the analyses. Nippon Professional Baseball had started "Green Baseball Project" in 2008, in which each player himself and team tries to save electricity through speedy play and to shorten the game length. Total electricity consumption in 2008 was reduced by 2.58% compared to 2007 and energy consumption by gas was also reduced, although the reduction ratio in the game length was no more than 1.4%. Furthermore, the degree in contribution of game length to total consumption of electricity increased in 2008. This cannot be explained by the reduction of game length, and these results suggested that some factors other than the game length also affected to the reduction of energy consumption such as the increasing awareness of players, spectators and stadium officers about energy saving, considering restricted contribution of game length to total electricity consumption.

著者

畦地 啓太 堀 周太郎 錦澤 滋雄 村山 武彦

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.35, no.2, pp.11-22, 2014 (Released:2019-02-15)

参考文献数

34

被引用文献数

2

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This paper aimed to clarify factors influencing environmental conflict occurrence during the planning stage for wind farm projects in Japan. After studying conflict occurrence situations and the main conflict issues for 155 large-scale projects across Japan, we focused on both physical and social factors as explanatory variables and applied a quantitative method using binary logistic regression analysis. The main findings were: (1) environmental conflicts had occurred in 59 projects as of May 2012 and the main issues could be classified as noise/infrasound, sediment- related disaster/hydrology, landscape, nature destruction and birds (esp. raptors); (2) turbine number and size were influential factors as structural aspects, while there was no significant association between proximity to turbines and conflict occurrence; (3) sites located within natural parks, national protection forests, sediment-related disaster hazardous areas and wildlife protection areas designated by relevant acts and ordinances showed higher conflict occurrence, and proximity to such areas could be influential as well; (4) habitats for Golden Eagle, Mountain Hawk Eagle, White-tailed Eagle and Steller's Sea Eagle significantly encouraged conflict; (5) in terms of social aspects at both the national and prefectural level, conflict occurrence was strongly associated with the existence of past conflict experiences and complaints about noise and/or infrasound generated by operating wind farms.

著者

小澤 暁人 本田 智則

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.41, no.6, pp.254-265, 2020 (Released:2020-11-10)

参考文献数

32

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Battery is a key technology in the transition to a low-carbon and resilient energy system. Recently in Japan, residential PV battery system is considered as one of the most promising applications; however, its impacts had not been fully assessed. This study evaluates the effects of residential PV battery system for end-users under various conditions on geological, technological and socio-economic factors. Regional diversity is considered by using data on residential power consumption and PV power generation that were collected from over 40 thousand all-electric houses in Japan. Scenario analysis and sensitivity analysis are performed to evaluate the effects of uncertain parameters on the system’s performances. Simulation results suggest that economic benefits of the system can be improved by changing battery operation mode at the end of purchase period for PV under Feed-in Tariff (FiT) scheme and the benefits should vary depending on the region. The results also indicate that PV self-consumption rate is over 50% when charging the battery with surplus power. Sensitivity analysis results suggest that the unit prices of grid electricity and the purchasing price of surplus power after FiT scheme should have large influences on the economic benefits of the system.

著者

森本 慎一郎 小池 政就 茂木 源人

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.29, no.4, pp.29-35, 2008 (Released:2019-09-26)

参考文献数

23

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Various evaluations have performed on oil peak forecasting, by confirming oil reserves data, forecast methods, opinions on reserve growth including non-conventional oil, and new oil field discoveries. However, a holistic overview of the oil peak forecast using statistical analysis, including the regression analysis method, would perhaps provide a new perspective from which to evaluate and confirm trends in the oil peak forecast. Therefore, this paper aims to clarify the principle factor contributing to oil peak forecasts by evaluating oil peak forecast studies from this new perspective. Oil peak year forecasts which predict that innovations in substitute fuels and the oil market force will be the primary contributing factors appear to have risen linearly, while those which indicate that the decline of world conventional oil production is the principle factor appear to be converging on the year 2010. The result of this paper evidently confirms that differing opinions regarding the basic cause of the oil peak have an impact on the oil peak forecasts as they appear in the trends for oil peak forecast studies.

著者

渡部 朝史 村田 謙二 神谷 祥二

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.30, no.3, pp.10-18, 2009 (Released:2019-09-14)

参考文献数

23

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Expanding energy resources for electric power plants from fossil energies to cost competitive renewable ones are required for reducing GHG emissions and for coping with the soaring in imported fossil energies prices. Importing natural energy resources as storable and transportable hydrogen transformed from wind power electricity may be preferable, if a large quantity of windmills are constructed in the favored oversea regions, such as Patagonia, where steady and strong wind is blowing over wide area and its electricity cost becomes low. Three kinds of electricity generating systems, based on domestic land windmills, domestic offshore windmills and that composed of electric power plant utilizing imported hydrogen, as mentioned above, are designed and the electricity costs of net power flows from such three systems are derived by estimating construction and running costs for the elements of such systems from open references. The result shows that the electricity cost derived from oversea wind power is comparable with that from domestic land wind power, if the future improvements of energy conversion efficiencies of electrolysis and hydrogen liquefaction are considered, though the construction cost for the oversea wind power system is more than twice of that of the domestic land wind power system.

著者

グリナ カミル 李 志東

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.31, no.5, pp.6-12, 2010 (Released:2019-08-26)

参考文献数

15

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This paper conducted quantitative study on the outlook of economy, energy and environment to 2030 of China Xinjiang Uygur Autonomous Region by using econometric method. GDP growth will be over 7% annually between 2006 and 2030, and total primary energy consumption will double by 2030. The continuation of rapid economic growth could result in a lot of difficulties for energy development, environment protection, and CO2 emissions reductions. For the sustainable development, more comprehensive strategies should be adopted, including development of renewable energy with highest priority, improvement in energy efficiency and automobile fuel efficiency, etc. However, substantial governmental involvements and support, as well as the establishment of a regulatory framework are necessary.

著者

岡本 優

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.41, no.5, pp.226-232, 2020 (Released:2020-09-10)

参考文献数

15

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Seaweed contains high high-density glucose, from which ethanol or materials such as biodegradable plastic, have been recently produced. A floatable block made from waste glass, that saves on labor and costs, has been developed to culture seaweed. Seaweeds collect nutrients such as nitrogen and phosphorus from eutrophic areas during cultivation. This floatable block would be able to supply nutrients, via a slow release method, in oligotrophic areas; this would constitute most of the exclusive economic zone (EEZ) in Japan. A shortfall in phosphorus supply is feared in the near feature, thereby making it necessary to obtain it from deep sea water through the cultivation of seaweed. The material for the floatable b lock would be supplied from coal ash or incineration ash, and so on by separating rare earth metals and metals using a high high-temperature melting furnace. The separated rare earth metals and metals may be recycled. Large volumes of ethanol made from seaweed can be used as a motor fuel. As the exhaust gases from an ethanol ethanol-fueled car are more toxic than those from a conventionally fueled one, under low low-temperature operation, catalyst activity would need to be assisted by electric discharge with a switching dev ice, namely MOS MOS-assisted gate triggered thyristor (MAGT), which achieves both high speed and high capacity. MAGT was developed for excimer laser.

著者

板岡 健之 木村 誠一郎 広瀬 雄彦 吉田 謙太郎

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.40, no.6, pp.242-249, 2019 (Released:2019-11-11)

参考文献数

10

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In response to the introduction of fuel cell vehicles (FCVs) to the commercial market hydrogen station deployment needs to be progressed. Since resources allocated for deployment are limited for either private companies who wish to install stations and governments who provide subsidies, efficient station allocation should be cognizant of the service of potential customers. Based on a literature review, the results of a social survey and data analysis, p-median is chosen to find optimum locations for hydrogen stations. Location and the amount on potential demand for FCV’s in the early stage of deployment is estimated by a regression model. The result of GIS analysis for short mid-term perspective using p-median implies the importance of covering regional hub cities (such as prefectural capital cities) as well as metropolises and the result of GIS analysis for long-term perspective implies the ultimate necessary deployment of hydrogen stations. The locations suggested by the analysis were examined through coverage analysis on existing gasoline stations. The geographical tendency of station locations allocated by the developed methodology provides guidance for hydrogen station location practice.

著者

有馬 理仁 林 磊 福井 正博 島田 幸司

出版者

一般社団法人 エネルギー・資源学会

雑誌

エネルギー・資源学会論文誌 (ISSN:24330531)

巻号頁・発行日

vol.39, no.3, pp.11-20, 2018 (Released:2019-02-08)

参考文献数

19

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The penetration of renewable energy is advanced to implement low-carbon society. Especially the increase of the photovoltaic generation energy is remarkable. But as a result, the trend that net electricity demand is decreased in the daytime and is increased suddenly in the evening, which is called ‘Duck-Curve phenomenon’ become apparent, and the destabilization of the utility grid caused by the fluctuation of photovoltaic generation power output. To solve this problem, the virtual power plant is planned as one of the solutions, and the battery aggregation using the distributed and cooperated rechargeable batteries is considered as one of the technical elements. One of the strong candidate of rechargeable battery is lithium ion batteries. To maximize the profit of the battery aggregation, it is necessary to diagnose the degradation in real time and estimate the cost effectiveness of lithium ion batteries. We found the convenient technique of diagnosis which can be done under operation of lithium ion batteries and battery management systems. To contribute to optimum system operation of the distributed and cooperated rechargeable batteries, we propose a new cost effectiveness index of lithium ion batteries based on this technique.