著者

水野 有智 石本 祐樹 酒井 奨 坂田 興

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.38, no.3, pp.11-17, 2017 (Released:2019-02-08)

参考文献数

19

被引用文献数

1

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This paper presents a cost analysis on hydrogen energy carrier supply chains using three different hydrogen energy carriers, such as liquefied hydrogen, ammonia, and organic hydrides (Toluene and Methylcyclohexane). An international supply chain from a foreign country to Japan by ship is the target of this analysis. The authors calculated hydrogen supply cost per 1 normal cubic meter in 2030 and 2050. For 2030 case, the cost, capacity, and efficiency of each facilities, which includes technological advancement to 2030, are summed up. For 2050 case, cost, capacity, and efficiency of facilities are assumed in order to realize the targeted cost 20 JPY/Nm3. The authors set comparable conditions among the carriers, calculated material and energy balances, assumed facilities in three supply chains, and got CAPEX and OPEX of the supply chains. As a result, the authors got two findings. Firstly, among three supply chains, there is small supply cost difference in both 2030 and 2050. Secondly, by comparing the supply costs of each carrier in 2030 and that of 2050, the authors found essential points of research and development; liquefaction, storage and shipping for liquefied hydrogen, composition and decomposition for ammonia, and dehydrogenation for organic hydrides.

著者

尾羽 秀晃 遠藤 聖也 松尾 雄司 玄海 亨 長尾 吉輝

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.4, pp.162-171, 2022-07-10 (Released:2022-07-10)

参考文献数

32

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Increasing variable renewable energies with zero marginal cost cause the decline of wholesale electricity prices and undermine their own value by “cannibalization effect”. While capital costs of renewable energies are expected to decline, their income is also to decrease because of declined wholesale electricity prices. This study integrated GIS (geographic information system) model that assesses business feasibility into an optimal power generation mix model that assess wholesale electricity prices. By developing an integrated model, it is possible to assess potential installation capacity of solar and wind energy by considering both economic rationality and land use restrictions. In the case of Japan, this study revealed that increasing solar and wind energies cause the significant decline of wholesale electricity prices in specific electric network area such as Hokkaido. Even if capital costs of these energies decrease through learning effect, economic potential of installed renewable capacities is significantly limited if business feasibility is considered. Thus, the decline of electricity prices by cannibalization effect can seriously stagnate installation of both solar and wind energies. This study implies that further cost reduction faster than previous trend is needed to realize “subsidy-free” energy sources when cannibalization effect is considered.

著者

魏 啓為 佐野 史典 秋元 圭吾 日渡 良爾 飛田 健次

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.5, pp.170-179, 2019 (Released:2019-09-10)

参考文献数

20

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This paper analyzed Japan’s fusion energy development scenarios by using a global energy systems model considering a combination of uncertainties of future socioeconomic development, CO2 emission pathways corresponding to the long-term target of the Paris Agreement and future fusion power plants. Fusion power plants will be installed in Japan and could contribute about 20% on average in power sector in the latter half of the century because of the limited-potentials of affordable renewable energies and carbon capture and storage in Japan. The benefit of fusion introduction in Japan is estimated to be about 10 billion US$/yr on average in 2050-2100. Its value increases with reduction of the capital costs of future fusion power plants, lower penetration of fission power plants and deeper decarbonization pathways. When considering unique characteristics of fusion energy development, i.e., long-term and large-scale projects and DEMO as a single step between ITER and a first commercial plant, demonstration and prospect of economic viability under DEMO projects becomes critically important. This systems analysis also suggests that an alternative option of fusion energy which directly produces hydrogen by high-temperature steam electrolysis could become economically attractive.

著者

大槻 貴司 尾羽 秀晃 松尾 雄司 森本 壮一

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.44, no.3, pp.115-125, 2023-05-10 (Released:2023-05-10)

参考文献数

14

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The authors’ previous assessment indicated that the marginal electricity cost in 2050 in Japan is more than doubled in an energy system based on a 100% renewable power supply compared to the cost-optimal system. However, some assumptions may be conservative given the recent developments, including the cost of variable renewable energy (VRE) and energy storage technologies and the availability of dispatchable renewable power generation (such as biomass-fired). Therefore, to test the robustness of the previous assessment, this study conducts a sensitivity analysis with a focus on these factors, using an energy system optimization model with a detailed temporal resolution. Simulation results imply that the high marginal electricity cost in the “100% renewable power system” is partially due to the costs of managing VRE’s seasonality. Low-cost energy storage and dispatchable renewable power plants can curb the marginal electricity cost. However, the results also suggest that the marginal cost in these sensitivity cases remains high compared to the cost-optimal system, still posing economic challenges to the system based on a 100% renewable power supply.

著者

山田 智之 坂東 茂

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.219-225, 2020 (Released:2020-09-10)

参考文献数

18

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After flexibility market will be established in Japan in 2021, the role of demand response (DR) will not be only for securing capacity (kW) and adjustment of power consumption (kWh), but also for adjustment of the power grid (⊿kW). Services which require faster response generally have higher market prices because limited resources are able to bid. DR services might be continuously monetized with the balancing market. To consider commercialization of DR and Virtual Power Plant (VPP) in Japan in the future, it is important to watch the foreign cases where ancillary service market operations are ahead, and to investigate price level and resource type there. We clarified price trends in three markets in the UK, Germany and the US, and resource type trends. In the UK and Germany, we conducted interviews with DR operators who hold demand-side resources to understand the actual situation and future directions.

著者

松尾 雄司 遠藤 聖也 永富 悠 柴田 善朗 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.40, no.3, pp.49-58, 2019 (Released:2019-05-10)

参考文献数

29

被引用文献数

2

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In this paper, we used an optimal power generation mix (OPGM) model, as well as meteorological data from 2000 to 2017, to assess the cost of achieving 100% renewable electricity mix in 2050 in Japan. Although the potentials of variable renewable energies, such as wind and solar PV, have been estimated to be large in Japan, grid-related system costs become significant in the cases with very high shares of variable renewables. Particularly, two factors affect the overall costs: The cumulative installed capacity of offshore-wind power, and the required capacity of electricity storage systems. The former is dependent on the curtailment ratio of onshore-wind and solar PV, whereas the latter is determined by the short-time “windless and sunless” factor, i.e. the maximum number of successive days with very small wind and solar power output. The analyses presented in this study highlight the necessity of using long-term meteorological data when estimating the economics of high penetration of variable renewables, as well as the importance of considering the risk of power supply disruption.

著者

佐賀 清崇 柳田 高志 リュドミラ ベスピャトコ アウン ウィン 藤本 真司 美濃輪 智朗

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.32, no.6, pp.1-6, 2011 (Released:2019-08-08)

参考文献数

10

被引用文献数

2

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This study evaluates three bioethanol production pathways that are composed by saccarification and fermentation process (SFP), gasification and chemical synthesis process (GCP), gasification and biosynthesis process (GBP). These pathways are designed by process simulator PRO/II, and these material and energy balances are calculated. From the simulation results, the CO2 emission reduction of each process is evaluated. It becomes clear that the CO2 emission reduction of the process via syngas is larger than that of the process via sugars. The ethanol yield of GBP is the maximum, and GBP can support oneself a power and thermal energy in the process. In three processes, therefore, the CO2 emission reduction of GBP is the largest. The ethanol yield of SFP and GCP is almost the same. Because the residue including lignin contains moisture, the thermal energy from which SFP can be recovered is not large. On the other hand, GCP can use the thermal energy generated by chemical synthesis for the power production. It is indicated that GCP has the possibility of increasing the CO2 emission reduction more than SFP.

著者

荻本 和彦 岩船 由美子 占部 千由 草柳 儀隆 宮崎 輝 安藤 希美 入江 寛 東 仁 礒永 彰

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.4, pp.171-179, 2023-07-10 (Released:2023-07-10)

参考文献数

24

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The massive deployment of PV and wind, which provides decarbonized energy supply, bring about various additional challenges, among those, the reduction of operational capacity of synchronous machines in a power system have been affecting stable operation of a power system. With the reduced system inertia, the system frequency deviates faster and more largely and the deviation sometimes results in instability of a power system operation. In this paper, we present the trend of system inertial reduction from 2030 to 2040 in Japan and quantify the cost increase when criteria of system inertia are applied. We further present the benefit of a PV PCS which can supply system inertia in terms of an improved system inertia profile and a reduction of annual operational cost in order to evaluate a strategy to maintain a system inertia.

著者

大竹 秀明 高島 工 大関 崇 Joao Gari da Silva Fonseca Jr 山田 芳則

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.36, no.4, pp.31-39, 2015 (Released:2019-02-14)

参考文献数

15

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A numerical weather prediction model (NWP) has become a useful tool for a forecast of photovoltaic power generation in an efficient operation of an energy management system (EMS). However, forecast products obtained by the NWP have certainly forecast errors. Before using forecast datasets of solar irradiance (or global horizontal irradiance, GHI), we have to understand error characteristic of GHI forecasts from the NWP. In this study, we validated GHI forecasts obtained from a local forecast model (LFM) of the Japan Meteorological Agency (JMA) using the surface-observed GHI data at the JMA stations. The LFM is a high-resolution NWP with horizontal grid spacing of 2km. First of all, case studies of GHI forecasts were conducted for different weather conditions. In cases of clear sky conditions and/or spatially large clouds, hourly-forecasted GHI values were significantly close to hourly observed-GHI values. However, significant forecast errors tended to be large in cases of high-level clouds (cirrus) and/or cumulus clouds. Seasonal and regional variations of GHI forecast errors were found from evaluations of forecast errors. Compared to a mesoscale model (MSM, with horizontal grid spacing of 5km) GHI forecasts, regional characteristics of LFM forecast errors were different from MSM forecast results.

著者

碇井 良平 飯野 友美子 松尾 雄司

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.43, no.5, pp.186-196, 2022-09-12 (Released:2022-09-12)

参考文献数

42

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In Myanmar, it is unclear how long the political turmoil caused by the military coup will last. However, one of the keys to sustainable economic development of the country and living standard improvement of the people continues to be tackling the increasing demand for electricity. This requires Myanmar’s government to construct an electricity supply system based on long-term planning and to consider the installation of international interconnection lines under the situation where many countries is starting to go forward to decarbonization. Therefore, this paper illustrates the preferable energy mix for Myanmar in 2050 from the perspective of the 3Es (economic efficiency, environmental sustainability and energy security) in multiple scenarios, setting different carbon prices and hydropower potentials for Myanmar. In conclusion, Myanmar should strongly promote hydropower development, including large-scale power plants, which will contribute to ensuring the 3Es, and also promote the development of international interconnection lines with neighboring Thailand, which will improve the fiscal revenue from the electricity export.

著者

星野 優子 杉山 大志

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.32, no.1, pp.22-27, 2011 (Released:2019-08-08)

参考文献数

15

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We compared the generation costs of photovoltaic (PV) with thermal and nuclear power during the period of the recent price surge of fossil fuels and raw materials by a bottom up analysis using a Japanese life cycle assessment (LCA) data for power plants. Although the steep rise of fossil fuel price had spurred the political mood in favor for renewable energy, we found that the impacts on the cost of PV systems by the price rise were not necessarily small compared to those on the costs of thermal or nuclear power. Due to the price hike of materials from 2003 to 2008, the cost of a PV system had increased by 2.7 yen per kWh. It is close to the price increase of coal power by 3.5 yen per kWh in the same period due to fuel and material price hike. Moreover, the impacts on the cost of a nuclear power were as small as 0.4 yen per kWh in the same period, in spite of the steep rise of uranium price. We conclude that a surge of resource and energy price does not necessarily make PV more cost competitive against nuclear and fossil fuel power, since PV is more material intensive than nuclear and fossil fuel power and the material price also surges when the fuel price does.

著者

上田 嘉紀 太田 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.43, no.3, pp.84-93, 2022 (Released:2022-05-10)

参考文献数

38

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As the electrification of the transportation sector is being promoted to achieve carbon neutrality, the promotion of battery electric vehicles (BEVs) has become an urgent issue. One of the concerns about BEVs from the user's point of view is the range anxiety that the vehicle may not be able to reach its destination due to power shortage. However, few studies have clarified the timing of the anxiety felt by users. In this study, a questionnaire survey was conducted on domestic users who switched from an engine vehicle to a BEV. As a result, it was found that the timing at which BEV users felt range anxiety and wanted to recharge their vehicles tended to be influenced by recharging habits based on individual personality factors, rather than environmental factors such as BEV driving experience and the density of rechargers. In addition, the SoC ratio of the timing of wanting to recharge was found to be correlated with the timing of recharging the BEV and the timing of recharging the cell phone.

著者

本間 優 土肥 哲哉 吉田 好邦

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.37, no.6, pp.23-31, 2016 (Released:2019-02-08)

参考文献数

42

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The objective of this study is to evaluate an agrivoltaic system by reflecting the deterioration of rice yield and quality. The agrivoltaic system means introducing photovoltaic power to agricultural fields. By the notification from Ministry of Agriculture, introducing renewable energy to agricultural fields became limitedly possible. However, current agrivoltaic pioneers do not always consider crop quality deterioration brought from a total life cycle shading. We evaluate a deterioration of growing in a paddy field in Chiba prefecture in Japan. Heading time delayed significantly under the shading condition. Number of ears and weight per an ear were also significantly less under PV panels. Utilizing measured data, we modified the conventional crop model, which simulates rice yield, quality and economic efficiency under the shading weather condition. A 20 percent shading reduces the yield by approximately 20 percent. Number of ears per root accounts for 84 percent of the yield, which indicates early period of the growth needs enough amount of solar radiation for improving the rice growth.

著者

西尾 健一郎

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.42, no.3, pp.175-184, 2021 (Released:2021-05-10)

参考文献数

16

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This study analyzed the factors causing the difference in the amount of utility bill payments by housing construction period, using micro data of about 9,000 households. The analysis consisted of (1) building a model of gradient boosting decision tree, which is one of the machine learning techniques, (2) identifying contribution of each household and each feature using SHAP value, which is a novel method to improve the interpretability of machine learning, and (3) revealing the breakdown of differences on a macro level by aggregating each contribution. The results showed that the factors that have reduced the amount of payments in recently constructed houses were partly caused by the spread of heat pump water heaters and IH cooking heaters, in addition to the improvement of housing insulation performance. It was also confirmed that the effects of higher efficiency refrigerators and lighting have been steadily increasing.

著者

張 鈺鑫 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.40, no.3, pp.28-38, 2019 (Released:2019-05-10)

参考文献数

37

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Japan and China are different in many aspects,such as population,resources,administration,growth stage, electricity mix,and carbon emissions.However,both countries are taking effort to transition to low-carbon society. One of those measures is to promote the development of solar power.In this research, we analyzed the current state and mechanism of PV development in both Japan and China by using econometric model. System price, feed-in tariff (FIT), subsidy, transmission grid improvement, etc. were confirmed to be an influence factor of introduction of PV system for both Japan and China. Also, in order to promote the international competitiveness of domestic solar cells, it is indispensable to expand cumulative output. Simulation analysis was also conducted on future targets formulated by the two countries. As a result, in reference case the tendencies continue as they are, it is predicted that Japan will reach a 130% completion of their objective by 2030, while China will have achieved a 142% by 2020. An effective way to further increase this spread could be found in the reduction of feed-in tariff policies ranges and interest rates, as well as in the increase of carbon taxes in Japan or their introduction in China, respectively.

著者

Myovela Rajabu 今中 政輝 栗本 宗明 杉本 重幸 加藤 丈佳 藤田 美和子

出版者

Japan Society of Energy and Resources

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.4, pp.257-266, 2021 (Released:2021-07-10)

参考文献数

19

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Fast Automated Demand Response (FastADR) is one of the expected measures to control electricity demand of consumers so that the balancing of electricity supply and demand in a short time horizon is improved. Due to their high power consumption in business buildings, Heating Ventilation and Air-conditioning (HVAC) loads are the promising resource for FastADR. However, because of their operational characteristics, HVAC loads do not perfectly follow external control signals. To mitigate this problem, Battery Energy Storage System (BESS) can be used complementarily. This paper proposes a method that coordinates the operation of building’s multi-units air conditioning system and BESS to reduce the required capacity of BESS for supporting HVAC operation in the FastADR. In the proposed method, the BESS discharges to supply the difference between the FastADR signal and HVAC load consumption and then recovers its energy by further adjusting the reference power consumption of the HVAC load, in which the thermal capacity of buildings is considered to reduce the required capacity of the BESS. Numerical simulations are performed to demonstrate the benefit of the proposed coordinated control.

著者

矢部 邦明 林 泰弘

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.40, no.3, pp.69-77, 2019 (Released:2019-05-10)

参考文献数

17

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This paper presents the change of CO2 emission when battery energy storage systems (BESS) are used for increasing self-use of PV energy from rooftop panels, and for decreasing PV output curtailment. A traditional evaluation uses an annual CO2 emission intensity and the charge-discharge loss is evaluated, and then the emission is increased. However, when PV system is largely penetrated and the PV energy curtailment is required by power system constraints, BESS can decrease the curtailment as well as the evening demand when the rate of thermal power is large, and increase the daytime demand when the rate of PV energy is high. So, BESS can decrease CO2 emission considering hourly CO2 emission intensity. Authors quantify these effects by use of an optimization model to minimize annual power generation costs, and a model to minimize annual costs of houses with PV and BESS, and then shows energy chain diagram including energy flow between generation plants and customers. The CO2 emissions from business use customers with PV and BESS, and power charging demand for EV are also evaluated using hourly CO2 emission intensity. Authors show BESS can decrease CO2 emission.

著者

Kenjiro Yagi Ramteen Sioshansi

出版者

Japan Society of Energy and Resources

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.5, pp.211-219, 2023-09-11 (Released:2023-09-11)

参考文献数

37

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Market power and unpriced carbon externalities are two failures that are common to wholesale electricity markets. We use a case study that is based on Japan’s wholesale electricity market to examine the impacts of addressing the former. Specifically, we compare Pigouvian taxes on carbon emissions and a renewable portfolio standard, which is an alternative indirect policy measure that is used commonly to reduce carbon emissions. We find that the benefits of Pigouvian taxes in reducing carbon emissions can be suppressed if market power is not addressed. This effect depends upon market structure, though. For the case of Japan’s electricity sector, this effect of market power is due to the industry being highly asymmetric. Carbon pricing increases the cost of carbon-intensive electricity-generation technologies. Lower-carbon generation technologies are held by firms with market power, which have incentives to withhold their capacity from the market to increase wholesale prices and their profits. As such, carbon pricing can result in high prices but muted carbon-emissions reductions. These impacts of carbon pricing are not observed if the wholesale electricity market is perfectly competitive.

著者

松原 雅 吉岡 剛 松橋 隆治

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.235-244, 2022-11-10 (Released:2022-11-10)

参考文献数

23

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Power retail companies have the risk of paying the penalty due to the imbalance between planned and actual power generation values. And the risk is supposed to increase in the future. Batteries and electrolyzers are a possible solution to reduce the imbalance. To mitigate the high installation cost of electrolyzers, it is important to increase the capacity factor of electrolyzers. In this study, a mathematical model was developed to simulate the operation of a power retail company using a battery and an electrolyzer. Then we proposed a new strategy to produce hydrogen using electricity from JEPX, when the wholesale electricity price is lower than a certain value. The model was formulated as a mixed integer linear programming problem, and the effect of the strategy was evaluated by solving this problem. As a result, this strategy achieved high capacity factor of the electrolyzer, around 60%. In order to reduce the risk of JEPX price fluctuation, we also proposed an electrolyzer’s operation strategy using the prediction error distribution of JEPX price. The effect was quantified through Monte-Carlo simulation. Although the deviation of the yearly revenue was not much reduced by this strategy, the high deviation was notably reduced in the daily revenue.

著者

山田 武史 所 寿洋 中島 忠司 中村 勇人 山野 健治 長井 孝之 笹川 雄司 一色 正男

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.1, pp.39-46, 2023-01-10 (Released:2023-01-10)

参考文献数

10

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In order to expand the use of renewable energy, a shift from "selling" to "self-consuming" of surplus electric energy generated by photovoltaic power generation (PV) is necessary. As for the means of the self-consumption, water heater with a hot water tank, which can store energy at relatively low cost as hot water, is attracting attention. Hybrid water heater, that has both an electric heat pump and a gas heat source, stores hot water to a relatively small tank compared to a simple electric heat pump water heater at less electric energy. Since it also has a gas heat source, there is no need to worry about running out of hot water even with a small tank. By combining a hybrid water heater and a storage battery system, an improvement of self power consumption ratio of PV energy is expected compared to the stand-alone usage of a hybrid water heater. This article reports the improvement result in an actual house. The self-consumption of PV energy used at the hybrid water heater was improved by 11.6 % in winter, 23.8 % in mid seasons, and 4.9 % in summer. Then the CO2 emission is reduced by 33 % a year.