Decarbonized energy system 脱炭素化エネルギーシステム


Decarbonized energy system


“Economical Evaluation of Hydrogen Cogeneration by Renewable Energies and Nuclear Energies ”

Hitomi Tanaka, Yuichi Ikeda 
Transactions of the Japan Society of Energy and Resources
2022 Volume 43 Issue 2 Pages 33-44 ,

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 International Energy Agency recommends reducing CO2 emissions to zero in 2050. In recent years, renewable energy has been increasing because decarbonization is essential in the energy sector. However, due to output fluctuations of solar and wind power generation, demand-supply balancing requires other power sources and energy storage. Therefore, we focus on hydrogen as feasible energy storage. We reconsider renewable energy and next-generation nuclear power plant as the power source for hydrogen production. In this study, considering the use of hydrogen, we analyze the feasible future energy generation from CO2 reduction and economic efficiency using linear mathematical modeling. The result shows that hydrogen plays a role in balancing peak demand with pumped storage power generation in 2050. Thermal power would be replaced with hydrogen as a demand regulator in the future. 


“Power grid with 100% renewable energy for small island developing states”

Y. Ikeda,
Evolutionary and Institutional Economics Review, 17, 183–195, 2020/01

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We estimated system-wise levelized cost of electricity (LCOE) for a power grid with a high level of renewable energy using our grid optimization model. The estimation results of the system-wise LCOE are discussed in terms of the nexus of energy, environment, and economic growth for Small Island Developing States (SIDS) economies. While 100% renewable energy is technologically possible with the usage of electricity storage, the estimated LCOE is as high as 397 $/MWh which is substantially higher than electricity prices for residential consumers in the US and Japan. The susceptibility analyses imply that the estimated LCOE increase of 223% with a 100% renewable power grid corresponds to an as high as 11% decrease in economic growth. This decrease in economic growth would have a significant negative impact on SIDS economies. However, hydrogen production via the electrolysis of water using the excess energy supply from solar photovoltaics would reduce the LCOE, and therefore, higher economic growth would be attained with less CO2 emission.

本研究では、グリッド最適化モデルを用いて、再生可能エネルギーを高レベルで導入した送電網のシステムワイズ電力コスト(LCOE)を推定した。システム単位での LCOE 推計結果を、小島嶼国経済のエネルギー・環境・経済成長のネクサスの観点から論じた。蓄電を利用すれば 100%再生可能エネルギーの利用は技術的に可能であるが、LCOE の推定値は 397 ドル/MWh と高く、米国や日本の家庭用電力料金を大幅に上回る。感受性分析では、100%再生可能エネルギー送電網を導入した場合の LCOE の推定値が 223%増加することは、経済成長の 11%もの低下に相当することを示唆している。この経済成長率の低下は、SIDS 経済に大きなマイナスの影響を与える。しかし、太陽光発電の余剰エネルギーを利用して水を電気分解して水素を製造すれば、LCOE を削減できるため、CO2 排出量を抑えて高い経済成長を実現することができます。

“Determinants of foreign direct investment in wind energy in developing countries”

R. Keeley, Y. Ikeda, 
Journal of Cleaner Production, 161, 1451-1458, 

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The renewable energy industry is one of the fastest growing industries attracting a great amount of foreign direct investment, being one of the top 5 industries in 2015 in terms of the amount of investment allocated. However, the allocation of foreign direct investment in the sector greatly varies between developing countries. Preceding studies have tried to explain the location determinants of foreign direct investment mainly by looking at the effects of institutional and macroeconomic factors. The renewable energy sector has been supported by various economic, regulatory, and political support policies. Considering the importance of these support policies, the paper analyses their effects on foreign direct investment as location determinants in comparison with that of the widely accepted determinants (institutional and macroeconomic determinants), focusing on wind energy in developing countries.

The results show that renewable energy support policies have equivalent or greater effect compared to the widely accepted determinants such as corruption level, price stability, access to finance, and GDP growth. The paper demonstrates the importance of analysing determinants of foreign direct investment focusing on a specific sector rather than looking at overall foreign direct investment. The paper also provides important policy implications including the need to improve the regulatory aspect of renewable energy sector such as access to grid infrastructure in order to attract foreign direct investment into the sector.


“Simulation Study on Energy Mix for Power Generation in Temburong Eco Town”

Y. Ikeda, edited by S. Kimura,
ERIA Research Project Report 2017, No.02,

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The eco town development plan in Temburong district, Brunei Darussalam, is about applying energy efficient technologies to achieve lower energy demand, especially electricity, to be used by buildings, and renewable energy such as solar photovoltaic (PV). Using a computer simulation model, this study seeks to determine appropriate capacities for both solar PV and electricity storage based on solar radiation data in Brunei and estimated electricity demand of commercial buildings for the eco town in Temburong district. There is already a diesel power plant in Temburong that installs 4 units x 3 megawatts (MW) power generation system, which provides electricity to subscribers in the area. In addition, about 6MW solar PV system will be installed soon. After installation of the system, electricity generation by the diesel station will be reduced. However, once new buildings are constructed according to the Temburong district development plan, more solar PV will be needed. In 2015 and 2016, ERIA collected climate data – solar radiation and rainfall data – in Brunei Darussalam to check intermittency caused by PV system installation. ERIA applied a dynamic simulation approach to check the intermittency under the combination of diesel power generation, solar PV system, and electricity storage. After the simulation, ERIA extracted the best capacity mix of diesel power, solar PV, and storage at minimum cost.

ブルネイ・ダルサラーム州テンブロン地区のエコタウン開発計画では、エネルギー効率の高い技術を適用して、建物で使用する電力を中心としたエネルギー需要の低減と、太陽光発電(PV)などの再生可能エネルギーの導入を目指している。本研究では、コンピュータシミュレーションモデルを用いて、ブルネイの日射量データとテンブロン地区のエコタウンの商業ビルの電力需要の推定値を基に、太陽光発電と蓄電の両方の適切な容量を決定しようとしている。テンブロン地区には既にディーゼル発電所があり、4 台×3 メガワット(MW)の発電システムを設置し、地域の契約者に電力を供給している。また、約6MWの太陽光発電システムも近日中に設置される予定です。システム導入後は、ディーゼルステーションの発電量が削減される。しかし、テンブロン地区開発計画に沿って新しい建物が建設されれば、より多くの太陽光発電が必要になるだろう。ERIAは2015年と2016年にブルネイ・ダルサラーム州の気候データ(日射量と降雨量のデータ)を収集し、太陽光発電システムの設置による断続性を確認した。ERIAは、ディーゼル発電、太陽光発電システム、蓄電を組み合わせた場合の断続性を確認するために、ダイナミックシミュレーションを適用した。シミュレーションの結果、ERIAはディーゼル発電、太陽光発電、蓄電の最適な組み合わせを抽出した。

“Development of the Eco Town Model in the ASEAN Region through Adoption of Energy-Efficient Building Technologies, Sustainable Transport, and Smart Grids”
Y. Ikeda, edited by S. Kimura,
ERIA Research Project Report 2015, No. 20,

“Cross-correlation of output fluctuation and system-balancing cost in photovoltaic integration”
Y. Ikeda, K. Ogimoto,
The Journal of Engineering, 10.1049/joe.2014.0235, 1-9,

“A unit commitment model with demand response and electric storage device for the integration of variable renewable energies”
Y. Ikeda, K. Ogimoto,
IEEJ Transactions on Power and Energy, 133, 7, 598-605+3,

“Impact of Smart Grid Technologies on Peak Load to 2050”
Steve Heinen, David Elzinga, Seul-Ki Kim and Yuichi Ikeda,
IEA Energy Papers from OECD Publishing,


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Decarbonized energy system



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