Sector integration is one of the major components considered when designing future smart energy systems. Due to the lack of data, current partitioning of consumers into residential, commercial, industrial, and transportation sectors is based on assumptions on their respective energy demand. In reality though, there is a diversity in preferences and behaviors so that consumers from the same sector may have different demand and consumers from different sectors may have similar demand. With the increasing amount of individual data, it is becoming possible to study this diversity and more accurately partition consumers using advanced analysis techniques such as clustering. However, while this approach does allow for an accurate grouping, the complex mechanisms at the roots of identified clusters are still unclear. Indeed, energy demand depends on multiple factors such as economic, political, cultural, social, or historical besides environmental conditions. The present study uses households’ data provided by the Japanese Ministry of the Environment with the objective of finding patterns associated with residential energy consumption profiles. It is found that the probability distribution of households’ energy consumption seems to be log-normal so that clusters are revealed by first applying a logarithmic nonlinear transformation. Furthermore, k-means clustering, which is commonly used in energy systems study, fails here to correctly identify the clusters when compared with density-based clustering. After identifying clusters, we look for statistically significant specificities in the corresponding households’ data such as their geographical location, number of residents, income, buildings’ construction year, equipment and vehicles and suggest interpretations for each.

地域のエネルギー需給の実態に根ざした脱炭素への取り組みを支援するため、東北大学の中田俊彦教授の研究グループは、「地域エネルギー塾湯データベース」を構築・公開している。

One of the major problems faced in the recurrence analysis of dynamical systems is the tangential motion effect affecting the structures in recurrence plots and their quantification. This issue roots to the choice of a threshold for recurrence, making it a crucial parameter for such analyses. It has been shown that a variable threshold following the dynamical changes of the system is more suited to the analysis of non-stationary data as it mitigates this effect. We study here the use of the distance separating successive points in the phase space as a reference for the recurrence threshold. The method relies on a single parameter while qualitatively and quantitatively providing stable recurrence structures as the previously suggested threshold based on the local maximum pairwise distance. This complete bottom-up approach is shown to be beneficial in the presence of abrupt transitions. It is also fairly noise-resistant and is not dependent on the sampling frequency in its normalized formulation. Furthermore, the sampling distance provides a clear reference for the occurrence of the tangential motion effect, allowing to define a default value for the threshold parameter to avoid it.

For achieving a carbon–neutral energy system, economical flexibility mechanisms are crucial to accommodate intermittent and decentralized renewable energy sources. Power-to-X (P2X) is a promising technology for this purpose. This study aims to elucidate the systematic effects and competition of dynamically operated power-to-X (P2X) technologies as a flexibility option in comprehensive renewable energy systems. We developed a linear programming model to optimize energy systems incorporating P2X technologies, including water electrolysis, methanation, Fischer–Tropsch synthesis, and Haber–Bosch synthesis, and investigated the impact of P2X flexibility on the system structure and energy costs, focusing on Japan as a case study. The results demonstrate that each P2X technology effectively shifts electricity loads and reduces curtailment by more than 80%. The contribution of each P2X technology varies, with water electrolysis playing a dominant role due to its relatively low fixed costs and large scale. Furthermore, the mechanism significantly reduces system costs by 35% and supply costs of electricity and hydrogen by 41% and 30%, respectively, by reducing the required capacities of electricity generators, stationary batteries, and transmission grids. Therefore, P2X has a cost advantage over these flexibility options. The results also highlight that the maximum effect is achieved when the capacity factor of P2X is 30%. However, synthetic hydrocarbons would require a carbon price of over 356 EUR/tCO2 to compete with fossil fuels. Domestic electrofuels would face tough competition with global fuel costs. Nevertheless, the reduction in electricity costs through P2X, along with its contribution to energy security, may incentivize its adoption.

エネルギーシステムの構成変化 2013年のエネルギーフローと比較 日本のエネルギーフローの現況として2020年版を図1に示す（1）。一年間に供給された一次エネルギー総供給量（TPES：Total Primary Energy Supply）は17.4 EJ（LHVベース）となり、2016年に作成した2013年版の19.0 EJに比べると8.5 %減少した。産業、業務他、家庭、運輸の各需要部門で有効利用されたのは5.54 EJのみで、全体の55 %にあたる9.6 EJが熱として廃棄されている。日本全体の正味利用エネルギー割合（総合エネルギー効率）は32 %と、前回の33 %とほぼ同じである。これは、火力発電効率の低さと、自動車のエネルギー効率の低さが主な要因である。発電効率を1と換算する再生可能エネルギーでは、太陽光発電が0.05 EJから0.67 EJに、風力発電が0.02から0.08 EJに増加しているが、全体から見ると両者の合計は0.68 EJと一次エネルギー総供給量の3.9 %に留まっている。

Recurrence plots along with their quantification measures have demonstrated their usefulness for the study of dynamical systems in many fields. The distance threshold for recurrence is a crucial parameter influencing the observed recurrence structures, thus, the related quantification measures, and have been the object of several studies to find its optimal value. We suggest here a definition of recurrence based on the local attractor density to obtain more qualitative recurrence plots capturing the dynamics at different scales without suffering from variations in the tangential motion effect. The method is qualitatively and quantitatively compared with common thresholding methods on different signals. It is shown that the suggested recurrence plot has more uniform line structures and is less sensitive to the threshold parameter. We also present a modification enhancing its robustness to noise.

In the new energy systems’ modeling paradigm with high temporal and spatial resolutions, the complexity of renewable resources and demand dynamics is a major obstacle for the scenario analysis of future energy systems and the design of sustainable solutions. Most advanced models are indeed currently restricted by past temporal energy demand data, improper for the analysis of future systems and often insufficient in terms of quantity or spatial resolution. A deeper understanding on energy demand dynamics is thus necessary to improve energy system models and expand their possibilities. The present study introduces noise-assisted multivariate empirical mode decomposition and recurrence quantification analysis for the study of this problematic variable with a case study of Japan’s electricity demand data per region. These tools are adapted to nonlinear, complex systems’ data and are already applied in a wide range of scientific fields including climate studies. The decomposition of electricity demand as well as the detection of irregularities in its dynamics allow to identify relations with temperature variations, demand sector shares, life style and local culture at different temporal scales.

The steam turbine has been a key component in electrical power generation since the 19th century, as one of the distinctive outcomes of the industrial revolution. In this chapter, we will show the method of cost evaluations and how they change with time. In addition to depreciation accounting, diversification of society’s needs leads to better innovation and raises the level of technology. The concept of technological learning is explained to find out how much costs decline with the popularization of technologies. Some generating technologies use similar components and these components learn at the same rate as these units are built. Technological progress mainly depends on three learning sources: learning-by-doing, research and development activity, and knowledge spillover.

As for research on sector-coupled energy systems, few studies comprehensively deal with energy carriers and energy demand sectors. Moreover, few studies have analyzed energy conversion functions such as Power-to-Gas, Power-to-Heat, and Vehicle-to-Grid on the energy system performance. This study clarifies the required renewable resources and costs in the sector-coupled energy system and cost-optimal installed capacity and operation. We formulated an optimization model considering sector coupling and conducted a case study applying the model in the Tohoku region. As a result, due to sector coupling, the total primary energy supply (TPES) is expected to decrease, and system costs are expected to increase from 1.8 to 2.4 times the current level. System costs were minimized when maximizing the use of V2G by electric vehicles and district heating systems (DHS). From the hourly analysis, it becomes clear that the peak cut effect by Power-to-Heat and the peak shift effect by Vehicle-to-Grid result in leveling the output of electrolyzer and fuel synthesizer, which improves the capacity factor reducing capacity addition. Since a large amount of renewable energy is required to realize the designed energy system, it is necessary to reduce the energy demand mainly in the industrial sector. Besides, in order to reduce costs, it is required to utilize electric vehicles by V2G and provide policy support for district heating systems in Japan.

In the carbon-neutral scenarios fixed by most developed countries, wind and solar resources play a significant role due to their substantial potential. Their instability can be mitigated through smarter designs of energy systems, including sector coupling and cross-border interconnections, which require detailed information on the spatial and temporal evolution of these intermittent resources. The present study aims at estimating the spatial–temporal energy potential of wind in Japan based on meteorological weather data. These data allow to analyze the potential of resources sharing to reduce power generation’s lack and excess, even in such an isolated country due to its variety of climate conditions and local energy demand. The correlation skewness is introduced as a measure of the sites’ uniqueness to identify important sites for the spatial distribution of capacity toward the efficient stabilization of supply at a national scale in a model-free fashion.

This study analyzes a regional biomass energy system in Japan. Herein, based on local characteristics, such as the heat load and distribution, we compared the woody biomass used for heat, electricity, and combined heat and power (CHP) with or without a district heating system (DHS). In this study, target demands were selected from the actual residential and commercial sectors of Koriyama City in Fukushima Prefecture using two maps of heat density. A heat pipe network between each buildings was designed using Dijkstra's algorithm, and the amount of woody biomass used in each case was fixed such that it satisfied the heat demands of heat-only boilers. Therefore, there were no meshes with unit heat densities >4.2 TJ/ha. However, we found areas with the required heat densities and selected 90 buildings for the DHS. The case that both CHP and DHS were installed and the CHP operational model followed the heat demand (i.e., the “CHP follow” case) was the most effective to reduce CO . When individual heat-only boilers were installed in buildings, the CO reduction was substantial; however, the capital costs associated with heat-only boilers were much higher than the those of the other scenarios. When a heat-only boiler and DHS were installed (i.e., the “Heat DHS” case), the CO reduction was competitive with the “CHP follow” scenario, however, total cost was more expensive. Furthermore, the cost of reducing CO would be larger than that of “CHP follow” case even if the CO emissions factor of grid electricity was less than half of its current value. 2 2 2 2 2

Mobile hybrid systems are expected to be key factors for a sustainable society. However, because of different sources of fuels for mobilities, there remains uncertainty of the actual value of mobile hybrid systems. A question arises of the benefit of introducing hybrids such as FCVs compared with conventional passenger vehicles such as ICVs and HEVs. This chapter describes studies on the analysis of hybrid systems’ characteristics in well-to-wheels using inventory analysis and forecast penetration of hybrids into the passenger transportation sector applying an energy-economic model. Analytical results indicate that FCVs have an essential benefit of reducing carbon emissions provided carbon-free hydrogen fuel by green electricity-derived electrolysis. FCVs’ price is the dominant expenditure in the total cost of ownership, which suggests the cost reduction’s security. The analysis indicates that FCVs’ penetration into the passenger transportation market requires a competitive price of the vehicle and a higher carbon reduction target.

This study evaluates the reductions in energy consumption of vehicle lightweighting, considering the effects of the end of life vehicles (ELV) recycling. For this propose, changes in the material composition of the body in white are assessed by an inventory analysis, including the entire life of the vehicle. The production phase is evaluated considering embodied energy values; the use phase through the mass induced energy consumption; and end of life vehicle recycling considers the part reusing, material recycling, and energy recovery as possible destinations. Moreover, the use of aluminum, advanced high strength steel (AHSS), and carbon fiber reinforced plastic (CFRP) as alternative materials are compared. The Japanese vehicle market has been taken as a case study. Furthermore, the user's cost comparison is addressed as an additional assessment variable. Our results show that the effects of vehicle lightweighting on the production and end of life phase are as essential to consider as the benefits generated in its use phase. Moreover, material lightweight must be analyzed jointly with its possible recycling destination, because when the first variable is considered individually, maximum life cycle energy reduction of 23.3 MJ per kg of part to be lightweight can be expected; however, an adequate combination of both variables could almost double those benefits to 51.0 MJ, but also incorrect combinations could be counterproductive guiding to an energy consumption increment of 92.7 MJ.

The aim of this study is to propose a dynamic model for forecasting the changes in the number of batteries recovered from end of life electric vehicles considering different power trains. To achieve a sustainable society, the dependency of the energy on fossil fuels must be overcome. One of the first steps to manage this objective is through the reduction of its direct consumption by the wide-scale adoption of EV (HV/PHV/BEV/FCV). Low cost and stable production of lithium ion batteries (LiB) are expected to be a key element for the electrification of the transportation. For this reason, an efficient cascade use of electric vehicle batteries (EVB) to minimize its raw material supply risk, disposal risk, environmental impact and material cost/consumption in its production process become essential. Additionally, by the promotion of a closed loop life cycle, cost reduction in the end of life batteries treatments can be also expected. However, to grab this opportunity and create a sustainable market, balance between the demand and recoverability of LiB must be clarified to propose reliable second life projects. This study proposes a method based on system dynamics modeling for forecasting the vehicle fleet, sales and end of life vehicles by power train considering data of scrapping rates of vehicles by year of use. Moreover, the supply potential of scrapped batteries from a reverse logistic scheme is analyzed. Here, the Japanese vehicle market is considered as a case study and a timeframe of 2018 to 2050 forecasted. Results indicate that the amount of scrapped EVB will increase 45 times from 2020 to 2050. Moreover, a complete closed loop of them can be expected around 2050 only if the exportation of used electric vehicles is hardly diminished.

This study presents an approach for estimating the offshore wind potential of Japan. Bathymetry data (1 km mesh) and near shore wind speed data of the year 2018 were used to assess the potential. A turbine with a peak power of 10.6 MW was employed for the analysis. The potential was calculated for multiple regions. These regions are based on the service areas of the major electricity supply companies in Japan. Overall, the results show that Japan has the potential to produce up to 32,028 PJ electricity per year. The electricity demand of 2018 amounts to 3231 PJ. The potential is therefore large enough to cover Japan's electricity needs ten-times over. The capacity that could theoretically be installed amounts to 2720 GW, which is a multiple of the current worldwide installed capacity of 29.1 GW (2019). In addition to the huge potential, the regional assessment shows that the regions vary greatly in their potential; of all the considered regions, Hokkaido and Kyushu have the highest overall potential.

燃料電池自動車の価値を理解するには、水素燃料供給と自動車走行時の統合評価が重要となる。Well-to-tankの水素供給特性とFCVのWell-to-wheelの走行特性のインベントリ分析の結果、FCVの普及にはグリーン電力を利用するCO₂フリー水素の利用が前提となること、総所有コストからみると、車両価格の低減が必要となることが明らかになった。

Bioenergy has been promoted in Japan with ambitious targets. However, the incentive schemes excluded renewable heat and overlooked synergies with local forest management, leading to the development of large-scale biomass plants that heavily rely on overseas biomass supplies. This case report discussed an alternative scenario of decentralised bioenergy systems supported with local biomass through five important questions. The currently available knowledge indicates that such a scenario is feasible with integrative forest management that considers both ecosystem services and multiple uses of wood. In addition to various environmental benefits, replacing imported fossil fuels with local biomass can also enhance energy security. Realising this scenario requires careful consideration of local context, empowerment of local governments and encouragement of both public and private initiatives.

The aim of this study is to comprehensively evaluate the energy consumption in the automotive industry, clarifying the effect of its productive processes. For this propose, the material flow of the vehicles has been elaborated, from mining to vehicle assembly. Initially, processes where each type of material was used, and the relationship between them, were clarified. Subsequently, material flow was elaborated, while considering materials input in each process. Consequently, the consumption of energy resources (i.e., oil, natural gas, coal, and electricity) was calculated. Open data were utilized, and the effects on the Japanese vehicle market were analyzed as a case study. Our results indicate that the energy that is required for vehicle production is 41.8 MJ/kg per vehicle, where mining and material production processes represent 68% of the total consumption. Moreover, 5.23 kg of raw materials and energy resources are required to produce 1 kg of vehicle. Finally, this study proposed values of energy consumption per mass of part produced, which can be used to facilitate future material and energy analysis for the automotive industry. Those values can be adopted and modified as necessary, allowing for possible changes in future premises to be incorporated.

2015 年にパリ協定が締結されて以降，世界の目標は低炭素社会から脱炭素社会へと変わり，企業などの事業運営を100% 再生可能エネルギーで調達するRE100 という国際イニシアティブに，日本の企業も次々に参加しています。エネルギーシステムの脱炭素化に向けてバイオマスはどのような貢献をするべきかを議論いただくべく，バイオマス部会では今回のパネル討論会を企画いたしました。参加者の方々には，それぞれの専門分野から見たバイオマスの現状や課題を挙げていただき，その上でFIT やインフラの問題，バイオマス利活用に伴う地域社会への貢献，次の時代を担う若者への提言などについて討論会を実施しました。パネリストの方々からは，バイオマスの熱利用，地域のエネルギーインフラ，需要家の意識，地域貢献が重要であり，それぞれに課題があるとあげておられました。最後には，若者への期待と激励を語っていただき，若者のチャレンジを支援する環境を提供することが重要であることも再認識される討論となりました。技術的課題にとどまらず，制度，政策，インフラ，意識など，多くの視点からバイオマスの利活用に求められる課題が提言される討論会となりました。研究者だけでなく，産学官でバイオマスに関わるすべての方々にご覧いただき，今後のバイオマス利活用にお役立ていただければ幸いです。

本研究では，持続可能な森林利用について森林資源を継続的に最大限利用するための計画と定義し，福島県奥会津地域を対象に伐出工程の林業機械の生産性について評価した。奥会津地域の森林空間情報をもとに持続可能な森林利用に必要な各年の伐出量を導出した。次に三島町西方地区において，複数の林業機械の組み合わせである伐出システムを設計し労働生産性を分析した。その後，奥会津地域全体にこの労働生産性を適用し，持続可能な森林利用のための所要人員数を分析した。結果，奥会津地域においては年間160 ～ 180 ha を継続的に伐出・造林する必要があった。三島町西方地区での伐出システムの生産性評価の結果，急傾斜林地では3.3 ～ 8.3 m ³/person-day，緩傾斜林地では38 ～ 53 m ³/person-day の労働生産性を示した。森林を伐出するための必要人員は，はじめの50 年間は34 ～ 110 人， 50 年目以降は34 ～ 76 人となった。労働生産性について他地域との比較を行ったところ，緩傾斜林地ではオーストリア等の林業先進国と同等程度の労働生産性であった。一方，急傾斜林地では現況のわが国と同等かそれ以上の労働生産性であり，林業先進国と同程度の生産性の実現のためには林内路網の拡充や実働時間の見直し等の施策が必要である。

In the context of rising concerns on climate change, efforts are made to improve our energy systems with the target of a carbon-neutral society by 2050. Energy systems are complex systems yet most modeling approaches do not consider their core aspects described by complexity science so far. These aspects can be grouped into Adaptation, Nonlinearity, Self-organization, and Network, which are interrelated and without which one cannot explain energy systems complex dynamics. The present study suggests the use of machine learning models to capture energy systems complexity. Some studies have already implemented machine learning for cluster analysis or forecasting purposes, but the potential of such techniques is still far from being fully exploited. We remind some understanding of complex systems then explain how machine learning models can complement or surpass current models as well as their limitations. Concrete examples are given for real applications.

This study aims to propose a model to forecast the volume of critical materials that can be recovered from lithium-ion batteries (LiB) through the recycling of end of life electric vehicles (EV). To achieve an environmentally sustainable society, the wide-scale adoption of EV seems to be necessary. Here, the dependency of the vehicle on its batteries has an essential role. The effcient recycling of LiB to minimize its raw material supply risk but also the economic impact of its production process is going to be essential. Initially, this study forecasted the vehicle fleet, sales, and end of life vehicles based on system dynamics modeling considering data of scrapping rates of vehicles by year of life. Then, the volumes of the critical materials supplied for LiB production and recovered from recycling were identified, considering variations in the size/type of batteries. Finally, current limitations to achieve closed-loop production in Japan were identified. The results indicate that the amount of scrapped electric vehicle batteries (EVB) will increase by 55 times from 2018 to 2050, and that 34% of lithium (Li), 50% of cobalt (Co), 28% of nickel (Ni), and 52% of manganese (Mn) required for the production of new LiB could be supplied by recovered EVB in 2035.

<p>Fuel cell vehicles are expected to be a key actor for coming hydrogen society in Japan. However, because of different source of fuel hydrogen, there remains uncertainty of the real value of FCVs. A question arises of what is benefit of introducing FCVs compared with other passenger vehicles such as HEVs and EVs. This study investigates the characteristics of FCVs in Well-to-wheels using inventory analysis and forecast penetration of FCVs into the passenger transportation sector applying an energy-economic model. Analytical results indicate that (1) FCVs have an important benefit of reducing carbon emissions provided carbon free hydrogen fuel by green electricity derived electrolysis. (2) Under the carbon reduction target of -80% in the year 2050, the share of FCVs in the passenger vehicle transportation sector reaches 14%, which is higher than 1% without carbon constraint. (3) In the total cost of ownership, price of FCVs is the dominant expenditure, which suggest the secure of FCV's cost reduction. The result of the study shows that the penetration of FCVs into the passenger transportation market requires competitive price of the vehicle as well as higher carbon reduction target.</p>

District heating systems (DHSs) which utilize excess heat play an important role in energy infrastructure in many European countries. In contrast to Europe, the DHS is not common and excess heat is not reused effectively in Japan. Almost all the DHSs in Japan were designed as first-generation district heating (1GDH) systems or 2GDH systems. No 4GDH systems have been introduced in Japan. The present study designs a 4GDH system utilizing excess heat from a wide area of Northern Japan and evaluates its feasibility. First, available heat amounts from two excess heat resources were calculated: waste incineration plants and thermal power plants. Second, heat demand from both residential and commercial sectors was estimated using a 1 km mesh, and a heat load curve was created for each mesh based on load curve data. Third, the DHS was designed with excess heat plants as a supply-side heat resource, and spatial information of the demand side made use of the geographical information system (GIS). Further analysis was conducted on selected DHSs in three cities in order to evaluate those systems’ feasibility based on energy efficiency, CO emissions, and economic aspects. The result shows that 70.5 PJ of heat can be supplied by DHS in Northern Japan, replacing imported fossil fuels such as petroleum and LPG with regional excess heat. The designed DHS could supply heat with equivalent costs compared to European countries. 2

The transportation sector constitutes approximately 25% of the total energy consumption and CO emissions worldwide. Therefore, in the last decades, several studies have been conducted to improve the energy efficiency of vehicles. A principal method to evaluate the total environmental effect of a vehicle is through the analysis of its life cycle. However, most of these analysis focused on the production and use phase, and little work has been performed to understand the material value of end-of-life vehicles (ELVs). Previous works have not comprehensively considered the benefits of the phase above that can provide a different perspective on the total vehicle life cycle. Our study clarifies how the materials obtained from scrapped vehicles are used, and we propose an analysis method to assess their benefits by defining the concepts of energy and CO reductions. The Japanese ELV market is presented as a case study, and the material flow is elaborated. The energy and CO reductions are calculated as 52.8 MJ and 2.80 kg CO per kilogram of vehicle, demonstrating the importance of the analyzed phase in the entire life cycle. Finally, possible changes in ELV recycling to improve their benefits are discussed. 2 2 2 2

今回の座談会では「バイオマスエネルギー利用のこれから」というテーマで以下の５つのポイントでご議論いただきました。・森林保全と地域再生・持続可能性と安定供給・熱利用と発電利用・FIT（固定価格買取制度）と将来の位置付け・海外のバイオマスと第二・第三世代バイオマス１つ目と２つ目のポイントは関係性が深く，現在，バイオマスの利用が活発になってきてはいるものの，採って使って植えるというサイクルで林業が回っていることが担保されていることが非常に重要であり，インフラを整えることによってさらにこのサイクルが円滑になり，ようやく森林保全，地域再生，持続可能性，安定供給が達成されること，それに向かって林業政策が整えられて行っていることが議論されました。３つ目と４つ目のポイントは，関係性があり，太陽光や風力など他の再生可能エネルギーにない特徴として熱利用を考え，コジェネでの熱供給を基本とし，熱需要をしっかりと考えていく必要があること，FIT終了後のバイオマス利用は経済的に自立した発電設備の稼働，バイオマスが持っている特徴を生かして調整力としての利用や液体燃料製造を考える必要があることが議論されました。５つ目のポイントでは国内のバイオマス利用と海外からの輸入に関して議論があり，地球温暖化対策としてのバイオマス利用に関して，両方の長所と短所が議論され，短期的な海外からの輸入や海外での液体燃料製造とその輸入，将来を見据えた国内バイオマス利用に向けたインフラ整備の重要性が議論されました。全体を通して，インフラ投資の重要性が多く議論されました。これまでの政策に基づいたバイオマス利用の結果の整理と分析，それに基づいて，これからのバイオマス利用に向けたインフラ整備，それに向けた横断的な政策が非常に重要であることが議論された座談会となりました。

<p>本研究では，マレーシアで発生するオイルパーム残渣の一つであるEFBを対象資源として，日本への国際輸送を考慮した持続可能なEFB利活用システムを設計して，定量評価することを目的とする。対象地域に賦存するEFB資源の収集，対象地域内の未処理のEFBの輸送，前処理，対象地域内のEFB燃料の輸送，国際輸送，日本にて化石燃料の代替の各要素からなるシステムを設計して，エネルギー収支，経済性，環境性を評価する。資源発生地点から前処理工場，港への輸送経路は，地理情報システム（Geographical Information System: GIS）を用いて最適化する。前処理としてペレット化，炭化，エタノール製造を考慮して，それぞれ火力発電所での石炭代替及び自動車のガソリン代替を想定する。その結果，CO₂削減コストが最も安価なのは，未処理のEFBを輸送せずにペレット加工するシステムであり，-4.35 USD/t-CO₂と負の値となった。また，炭化，エタノール製造する場合のCO₂削減コストはそれぞれ141, 393 USD/t-CO₂となり，日本にて木質ペレットを製造することを想定した先行研究に比べて安価となった。感度解析では，資源の利用可能量が炭化及びエタノール製造のCO₂削減コストに与える影響が大きく，ペレット化のCO₂削減コストは大きな変化がないことが示された。</p>

The purpose of this study is the analysis and the integrated design of sustainable EFB (empty fruit bunch) supply chain from pelletizing to exporting. In this study, Malay Peninsula is set to be as an analytical target place, supply chain of EFB pellets as a biomass derived from oil palm are analyzed in different cases. In order to grasp the difference of the whole system performance in cases, a simple mill case and multiple mill case are prepared. Cases include two cases “EFB concentrated processing case” and “EFB distributed processing case”. Supply chain is composed with three sectors, resource, supply and demand, and this study analyzes the supply sector. Processes of the supply sector are extract, transport, dry, pelletize and ship. By differing the layout of the dry process before and after transport in two cases, case 1-d and case 1-w, influence of the difference in water content of biomass is evaluated in each case. Based from the retail analysis, CO emission of EFB distributed processing case is 2.60 kg-CO /GJ-pellet and resource utilization rate of this case is 62%. By substituting coal by EFB pellets, 0.08 t-CO /GJ-pellet is reduced. 2 2 2

<p>The purpose of this study is to design a sustainable supply chain of wood biomass fuel by applying a mixed integer programming (MIP: Mixed Integer Programming). To evaluate the effect of routing choice quantitatively, two objective functions are defined; cost minimization and energy consumption minimization. In the Railway case, 4 t truck can be used to transport wood logs and pellets, and railway can be used to transport pellets. In the Heavy truck case, three types of trucks (4 t, 10 t, 20 t) can be used to transport wood logs and pellets. As a case study area, five prefectures of Japan's Tohoku region are selected. The computational result provides that supply cost becomes 17,058 - 24,773 JPY/t_pellet. In any case, since cost of pellet supply is lower than distribution price of pellet which is 45,000 JPY/t_pellet in Japan, letting break-even point to distribution price of domestic pellet, this system has competitiveness to Japanese pellet suppliers. Effective utilization rates of biomass resource through supply chain show 0.802 - 0.834 that is higher than the previous study using waste woods. The CO₂ reduction by coal substitution shows 0.967-1.029×10⁶ t-CO₂/year which shares 65 - 69 % of CO₂ emission from the coal combustion.</p>

The aim of this study is to quantitatively evaluate the benefits of reused vehicle parts through a material flow approach. The energy consumed by new components for vehicle repairing can be saved. Moreover, an appropriate use of materials obtained from end-of-life vehicles (ELVs) contributes to waste reduction. Each reused part has different material compositions, weights, and demand; thus, the total benefit is evaluated using inventory analysis by introducing the definition of embodied energy and CO₂ emissions. The Japanese ELV market was taken as a case study, and the results show that energy and CO₂ saved by reusing parts are approximately 35.3 GJ and 1,887 kg-CO₂ per vehicle, and 111 PJ and 6 MM ton-CO₂ for the market in Japan. Finally, possible measures to boost the current benefits are discussed.

This paper aims to estimate the costs and CO emissions of wood biomass co-firing in the Tohoku region of Japan. A woody biomass supply system is designed, which comprises of four processes: collection, resource transportation, preprocessing, and fuel transportation. Preprocessing is further divided into two processes: drying and fuel production. Sawmill residue, construction waste, forest residue, thinning residue, and fruit-tree pruning residue are treated as raw materials. Wood chips, pellets, and torrefied pellets (known as black pellets) are regarded as bio-fuels. The raw-material and bio-fuel transportation pathways are optimized using a geographical information system (GIS). In the Tohoku area, the availability of raw-material is 3.6 PJ/y, and the results indicate that the preprocessing plant locations should be widely distributed in that region, because the resource transportation costs have a significantly greater influence on the costs and emissions than the scale effect of the preprocessing facilities. The chip production case exhibits the smallest energy consumption of 3.8 GJ/t, the lowest supply cost of 1558 JPY/GJ, and the largest CO reduction of 252 × 10 t CO /y, whereas the pellet production case exhibits a supply cost and CO reduction of 1643 JPY/GJ and 229 × 10 t CO /y, respectively. The energy consumption, energy waste, and cost of torrefaction are greater than the reductions in the transportation energy and cost due to wider distribution of the preprocessing plants; thus, the black pellet case has a larger supply cost than the chip and pellet cases. 2 2 2 2 2 3 3

Near-field scanning optical microscopy (NSOM) overcomes the diffraction limit, thereby realizing a spatial resolution far beyond the wavelength of light used. However, NSOM still has a problem in repeatable imaging at the high spatial resolution and high contrast with conventional aperture or apertureless probes that are needed for practical applications. Here, we describe an optical imaging technique based on plasmonically excited cascade near-field coupling that has the potential to achieve single-nanometer spatial resolution with high imaging repeatability. This technique makes use of a plasmon waveguide coupled with a high-stiffness carbon nanotube optical probe. Through the action of surface plasmon polaritons, the input far-field light is converted into an optical near field that is used as an excitation source. This excitation near field is strongly enhanced and concentrated on the probe tip such that it generates a second near field as a nanosized probe spot on the apex of the tip. Extremely high-resolution optical imaging is accomplished by scanning the sample surface with the probe spot. At a wavelength of 850 nm, a 5-nm-wide metallic striped pattern on a cross-sectional superlattice sample was clearly resolved as a permittivity distribution. Published by AIP Publishing.

The UNFCCC has stated that energy policies and measures to address climate change should be cost-effective to ensure global benefits at the lowest possible cost. To mitigate the bulk of carbon emission from the electricity sector, a large market penetration of renewable energy technologies with as low cost as possible is a key research topic. The energy-related R&D policy in Japan aims to achieve a green economy. In our study, based on this context, we demonstrated how to optimize the timing of public R&D investment within the framework of a bottom-up partial equilibrium model. The developed optimization model represents the Japanese electricity sector and minimizes the total system cost subject to an accumulated carbon emission constraint. Our main research focus is the role of R&D activity, especially in the innovation stage of renewable technologies. We employ a two-factor learning curve and quantify the impact of the learning effect on the dynamic diffusion of major renewable technologies. The study shows a dynamic technology transition in the Japanese electricity sector and the optimized R&D investment schedule for each renewable technology. With the first-best energy policy, an R&D budget of more than 2000 million USD would be allocated to PV in 2050, which corresponds to 45% of the energy-related Japanese R&D budget in 2050. Because some have criticized the uncertainty problems with dynamic simulations and learning models, supplemental sensitivity analyses are included.

<p>本研究は，木材の素材から最終利用までの定量性を可視化した，木材フロー図を作図することを目的とする。木材フロー図は，国内の木材利用の現状を理解するために必須であり，木質バイオマスのエネルギー利用を含めた木材利活用システムの設計の基礎となる。まず，国内の製材，合板，集成材，プレカット，チップ，パルプの各工程の製品生産量，残材の発生量及び用途を，丸太や解体材・廃材等の供給量及び各工程の歩留まりに基づいて推計する。得られた値を，各工程及び製品の統計値と比較した結果，概ね一致することが示された。推計値を可視化して，2014年の木材フロー図を作成した結果，木質バイオマスのエネルギー利用は，木材加工の残材や解体材・廃材がおもであり，燃料材が国産丸太に占める割合は10％に満たないことが明らかとなった。また，各工程の残材は合計8.1百万m³発生して，チップ加工に3.3百万m³，自家消費に1.8百万m³供給される等，約95％が利用されること示された。そのため，木質バイオマスのエネルギー利用量を増加するためには，国産丸太をエネルギー利用することが求められる。また，木材自給率が向上することを想定した将来の木材フロー図を作成した結果，丸太の輸入量はゼロとなり，国内生産量の増加に伴い残材の発生量が増加することが示された。一方，パルプ用チップの輸入量は16.0百万m³となったので，さらに木材自給率を向上するためには，国内産の木材を使用してパルプ用チップを生産することが求められる。</p>

This paper presents a geographic information-based mixed integer linear programming model for a district heating system design. The model minimizes the annualized investment and operation costs of the system, with the key results showing the optimal distribution network structure and optimal capacity and dispatch of heat plants. A network topology of nodes and edges, providing accurate geographic representation of the district, is generated using a geographic information system and acts as a constraint. A case study is conducted for a district in Hirosaki city, located in the northernmost prefecture of mainland Japan. The results demonstrate the considerable economic benefits of integrating locally available woodchips in heat-only boilers instead of using city gas due to lower fuel costs. Low temperature operation reduces the fuel costs due to less network heat loss compared to medium temperature operation, but it is overcome by the cost of the larger pipe size and the pumping power. Implementation of the district heating system to the case area encourages sustainable development through economic favorability, decreased primary energy consumption, and considerable CO2 emissions reduction, compared to the current heat supply structure.

To find a balance between food and energy security, this research presents the design of an energy self-sufficient farm in electricity, heat and bioethanol, which is produced by energy crops and agricultural residues. The farm proposed is evaluated by two models: Land Optimization and Cost Optimization. Due to the food–fuel debate over land and the detriment of food security, this research proposes utilizing the current abandoned land and increasing the food self-sufficiency ratio (FSSR) of the crops analyzed (rice, wheat and maize). The farm is optimized for several food and fuel demands, with a maximum farm unit size of 100 ha. The result is a myriad of farms of different sizes, each optimized for a certain demand. Subsequently, the amount and variety of such farms are optimized maximizing the food and fuel produced for each city of the case study (Miyagi Prefecture, Japan). The results suggest that the establishment of energy self-sufficient farms in the abandoned land can stimulate the biofuel industry and increase food security simultaneously. The FSSR of maize and wheat can be improved in approximately 10–25 and 7–9 %, respectively. The estimated bioethanol potential is 3.2–3.8 ML. Additionally, a surplus of electricity and heat, approximately 61–65 GWh and 60–165 MJ, respectively, is obtained. As the Land Optimization model proposed is sensitive to crop yields, a simultaneous evaluation is recommended. The results also suggest that the farms must be larger than 8 ha to achieve self-sufficiency; therefore, the policies involved need further evaluation.

<p>Improving national energy security has been recognized as one of the most important perspectives of energy policy in Japan. On the other hand, a notion of higher energy resilience has recently become common to make a domestic energy supply system stable since the Great East Japan earthquake occurred in 2011. Therefore, a purpose of this study is to establish frameworks that evaluate energy security and energy resilience quantitatively to design a sustainable energy system. An advanced framework for energy security evaluation is developed in which Resource Diversity, Import Price, Import Region Diversity, Environmental Impact and Energy Efficiency are selected as criteria, where each criterion is normalized between 0 (extremely low security) and 1 (extremely high security). In addition, a multi-objective analysis using the augmented ε-constraint method (AUGMECON) is conducted to determine the best energy resource configuration for a Japanese energy system from the perspective of both energy security and economic feasibility. On the other hand, energy resilience evaluations are conducted in accordance with four steps: identifying risks, assessing risks, building resilience, and evaluating resilience. Energy resilience is evaluated based on two criteria. The first one is <i>Resilience Index</i> which is calculated by a ratio between energy supply and energy demand. The second one is an economic loss incurred by a sudden energy supply interruption. In conclusion, in order to develop a sustainable energy system in Japan, it is important to increase the proportion of renewable energy consumption, which contributes to enhancing both national energy security and regional energy resilience.</p>

The steam turbine has been a key component in electrical power generation since the 19th century, as one of the distinctive outcomes of the industrial revolution. In this chapter, we will show the method of cost evaluations and how they change with time. As well as depreciation accounting, diversification of society's needs leads to better innovation and raises the level of technology. The concept of technological learning is explained to find out how much costs decline with the popularization of technologies. Some generating technologies use similar components and these components learn at the same rate as these units are built. Technological progress mainly depends on three learning sources: learning-by-doing, research and development activity, and knowledge spillover.

微粉炭焚き火力発電所はベースロード電源として重要でありながら CO2 排出量が多く，この削減が必須とされて いる.カーボンニュートラルな木質バイオマスの混焼はその有力な手段であるが，国内に豊富な森林資源をもちな がらも実際の混焼率は数%( 熱量比 )程度にとどまっている.当社は，熱量ベースで 50%混焼を目標とし，木質 バイオマスのサプライチェーンを含むトータルシステムの検証と実証に大学と連携して取り組んだ.最終年( 2015 年 )度には，森林伐採から収集，加工，輸送，150 MW 級商用火力発電所での混焼発電に至る実証試験を実施し， 純国産燃料を用いて混焼率 25%( 熱量比 )を実証した.

<p>The purpose of this paper is to analyze energy consumption and supply on a prefectural scale, and to visualize and compare the regional energy demand-supply distribution considering potential of renewable energy. The final energy consumption and the final energy consumption per capita are related to the industrial sector. Total final energy consumption is reported to be 13,297 PJ, of which 6,136 PJ is used for the industrial sector. In the residential and commercial sector, population is the most effective on the final energy consumption. On the other hand, final energy consumption per capita in residential sector is tied to the climate: cold areas like Hokkaido, Tohoku, and Hokuriku have larger consumption than other areas. Energy expenditure per capita in residential sector is also large in cold areas; for instance, 98,581 JPY/capita is spent for energy in Hokkaido. The energy supply system in Japan depends on thermal power generation that is large scale-centralized; Chiba has the largest thermal power generation estimated at 390 PJ. By contrast, thermal power generation in Yamanashi is the smallest in Japan estimated at 0.5 PJ. Renewable resources are widely distributed in Japan, but renewable energy supply which is calculated at 374 PJ is very small. Onshore wind power and solar power have enough potential, evaluated at 2,985 PJ, to substitute thermal power plants. This study indicates that development of local energy systems, especially local heat supply system, is important to introduce local renewable energy, and introduction of renewable energy leads to more balanced regional energy demand-supply distribution.</p>

In this study, we estimate supply potential of carbon-free hydrogen from wind power in Japan using spatial information such as wind speed and the land use. Then, hydrogen supply cost is revealed for every municipality in the Tohoku districts considering hydrogen production to distribution. The estimation indicates that the supply potential of carbon-free hydrogen in Japan is as much as 205 billion Nm³/year. With that amount of hydrogen a fuel cell vehicle can drive 3,030 billion km. When a high-pressure gas transport system is used for delivery of carbon-free hydrogen from each municipalities to Sendai city, the hydrogen supply cost ranges from 159.8 to 257.0 JPY/Nm³, and the average cost is 180.6 JPY/Nm³. If all cost component of carbon-free hydrogen supply system are replaced by the future cost target, the supply cost range decreases to 82.4~137.3 JPY/Nm³ and the average cost is 99.4 JPY/Nm³. The driving cost of fuel cell vehicle by this future hydrogen supply cost ranges 5.60~9.31 JPY/km and the average cost is 6.72 JPY/km. This cost is cheaper than 7.01 JPY/km of the internal combustion engine vehicle fueled with gasoline.

わが国では，一次エネルギーの94パーセントを輸入化石燃料に依存して，大量のCO₂排出に加えて国内資本が海外へ流出している．本研究では，福島県を対象として地域資源を有効利用する低炭素でかつ地域経済活性化に資する持続可能なエネルギーシステムを設計することを目的とする．地域に賦存する再生可能エネルギー資源量を推計し，県内の電力・熱需要を満たすエネルギーシステム構成を線形計画問題を解いて決定する．さらに，設計したシステム性能を経済波及効果など多様な観点から評価し，持続可能なエネルギーシステムの価値について考察する．設計の結果，風力発電導入量の増加と木質バイオマス資源を燃料とする地域熱供給システムの実現を通じて，地域資源を有効利用してかつ海外流出するキャッシュが大幅に減少可能なエネルギーシステムを構築できることが明らかとなった．

Hydrogen supply infrastructures such as hydrogen production and filling stations are expected to accelerate the penetration of fuel cell vehicles. This study focuses on a hydrogen material flow from the production to the consumption sector to discuss hydrogen supply potential in Japan. Both the hydrogen supply capacity and demands are investigated to estimate hydrogen sales and its self-consumption status based on the current data. The difference between the supply capacity and consumption quantity is defined as a surplus hydrogen capacity. Detailed estimation indicates that the surplus hydrogen capacity affords to supply high purity hydrogen up to 8,700 million Nm³ a year, which is equivalent to 3.3% of the final energy consumption in Japan's transportation sector in 2012.

This article addresses the selection of electricity generation technologies for a decentralised electricity generation system based on local renewable sources for a rural area of a developing country (six municipalities in Western Honduras). In this work, rather than designing a high-reliable electricity generation system with high-quality power, our objective is to provide the basic configuration of an energy mix for a rural area for which energy data are not of high resolution. The selection of technologies is accomplished through a non-linear integer programming model that minimises the levelised cost of electricity (LCOE). The model uses as inputs information related to the energy resources, the conversion technologies, the Honduran economic framework, the electricity demand of the study area, and the energy storage cost. The evaluated energy resources are solar, wind, and local biomass, while the electricity generation technologies considered include solar photovoltaics, wind turbines, biomass direct combustion with a steam turbine, and biomass gasification with a gas engine. Three different case studies were proposed as functions of power capacity: off-grid, mini-grid, and grid-connected. For each case study, the model outputs are the electricity supply share for each technology, the LCOE, and the number of power plants with the respective power capacity required to satisfy the electricity demand of the study area. This work can serve as a reference for preliminary feasibility studies of electrification projects based on renewable energy sources for other rural areas in Honduras or in other developing countries.

The present work intends to address the lack of energy access and low waste collection services through the integration of waste-to-energy (WTE) technologies into the electrical system, aiming for a low-carbon growth. A minimization of cost approach was applied using linear programming. Venezuela was used as the case study for five cases under two scenarios. In Scenario A, the current waste collection service rate was considered (88%), whereas in Scenario B, it was assumed to improve to 94%. Cases 1 to 5 were as follows: Current fuel subsidy, No fuel subsidy, Subsidies on WTE, Carbon tax policy and Carbon-reduction policy. Total carbon emissions were analysed. In all cases except for the first one, WTE technologies were present in the energy matrix, reducing carbon emissions by approximately 3-5.4 × 10 tonne of carbon. Furthermore, a difference of 1-2 × 10 tonne of carbon between scenarios was observed. The last two cases achieved higher emission reductions with an abatement cost of $169 tC and $89 tC , respectively. Despite the lower abatement cost of the carbon reduction policy, this research proposes the implementation of a carbon tax because it could finance the improvement of waste management practices. 6 6 -1 -1

This paper presents a high spatial resolution based method for design and operation of a low temperature district heating system and evaluates its feasibility and energy and exergy performance through case comparison. Selected case area is existing district in North Japan. The district heating system design and operation follows a bottom-up approach. The study scope takes into account the demand side, distribution and supply side where biomass CHP (combined heat and power) plant is selected as main supply source. Radiating floor heating system model is used to estimate building temperature requirement. Results indicate that low temperature heating is infeasible for non-residential buildings in North Japan at high loads. Improving building insulation decreases heating quality demand considerably. Low temperature district heating performs better than medium temperature, especially in terms of exergy efficiency, however requires a bit larger pipe diameter indicating cost trade-off between installation and operation cost. Implementing cascade configuration based on quality level of building energy demand results in highest system performance. Lower network temperature provides least net primary energy consumption primarily due to higher electricity generation of CHP plant. This transcends to favourable system exergy efficiency of low temperature operation due to high quality of electricity, increasing the exergy of the product.

The purpose of this study is to estimate the woody biomass potential based on the wood material flow. The wood flow is drawn based on the statistic data from Japan's Forest Agency and METI. Woody biomass potential is estimated using the timber volume in 2007 and 2012, and the wood material production. The timber volume in Japan is 2,658 million m^3 in 2007, and 3,048 million m^3 in 2012. And annual wood production is 14-15 million m^3/year. Thus, the forest growth amount is 93 million m^3/year, and the sustainable availability is 52.9 million m^3/year. Based on the wood material flow, the woody biomass availability for energy is 10 million m^3, higher heating value 72 TJ/year.

本研究は，マテリアルフロー及びエネルギーフローに基づいて，資源の有効利用を考慮したバイオマスエネルギーシステムの評価指標を構築することを目的とする。システムの構成要素は，資源の栽培・収集，前処理（バイオ燃料製造），エネルギー変換，廃棄物処理の４つとして，資源及び燃料はバイオマス資源，バイオ燃料，化石燃料を対象とする。従来の評価指標であるエネルギー収支比(EROI) は，単位量あたりの化石燃料を消費して得られるバイオ燃料のエネルギー量で定義され，バイオ燃料を製造するために消費したバイオマス資源の量を考慮していない。本研究ではマテリアルフローを考慮して，バイオマス資源のエネルギー量を基準として，バイオマス資源を加工して得られるバイオ燃料のエネルギー量と，バイオマス利用の過程で消費される化石燃料のエネルギー量の差を，資源有効利用率と定義する。また，エネルギー変換の影響を考慮して，バイオマス資源をエネルギー利用することに伴い代替される化石燃料の量を，化石燃料代替係数と定義する。木質バイオマスを対象としたケーススタディを行い，マテリアルフローに基づいて評価，比較した結果，EROIと，資源有効利用率及び化石燃料の削減量は，傾向が異なる場合があることを明らかにした。

Depending on the technology used to produce liquid biofuels, they can be classified into: first-, second-, and third-generation biofuels. The first generation uses as feedstock edible biomass such as corn and sugar cane, the second generation uses lignocellulosic biomass such as forest residues, and the third generation uses algae. The technologies employed to produce first-generation liquid biofuels are more developed and mature than those employed by the second- and third-generation. However, the fact that they use edible crops as feedstock leads to a debate about the negative impacts that this can cause in an economy, particularly over the prices of the food sector. This work joins this debate by analyzing the economic impacts that introducing ethanol produced from rice can cause in the Japanese economy. A comparative-static, multi-sector, Computable General Equilibrium (CGE) model is used to execute the analysis. The model simulates a neoclassical economy where producers maximize profits subject to technological constraints, and households maximize utility subject to budget constraints. It incorporates intermediate demands, has a government and an investment agent, and includes the rest of the world interacting with the economy through exports, imports, and transfers. Different case study scenarios have been set based on two criteria: the bioethanol production process and the gasoline-ethanol mix ratio. Among the bioethanol production processes, an only ethanol production system, and an ethanol and power production system are considered. For the gasoline-ethanol mix ratio the model includes a biofuel penetration rate parameter that represents how much of the gross output of the gasoline sector is replaced by the new biofuel. We run various simulations for different values of this biofuel penetration rate parameter (in a range from 5% to 85%) with the intention to cover all the common ethanol fuel mixtures standards. The relevance of the study is that understanding the consequences of introducing biofuels into an economy is crucial to be able to design a supportive policy that helps to enhance the positive effects and decrease the negative ones.

The purpose of this paper is to estimate the feasibility of a low-carbon society in Japan through developing an energy flow, carbon flow and cash flow. In addition to total primary energy supply (TPES) and final energy demand, the energy flow contains estimated renewable energy potential, energy services and energy losses. TPES in 2012 is estimated as 18.9 EJ, of which 17.9 EJ (= 17.9 ×10¹⁸ J)was supplied by fossil fuels. Total renewable energy potential is estimated as 21.2 EJ which is enough to meet Japan's TPES. Wind energy has large potential of 18.3 EJ. As for demand sectors, the transportation sector has the largest energy losses, 2.62 EJ, due to low energy efficiency. Total CO₂ emission in 2012 was 1,223 Mt-CO₂, of which 956 Mt-CO₂ was emitted from both coal and petroleum. Coal is mainly supplied to electricity generation sector, and petroleum is supplied to transportation sector. Total payment for energy supply in final demand sector is estimated to be 41.9 trillion JPY. Total CIF price of 20.6 trillion JPY is paid to foreign countries due to imported fossil fuels. This study indicates that introduction of renewable energy and energy supply system transition, in particular of the transportation sector and electricity generation sector, leads to CO₂ reduction and revitalizes local economies. Wind energy, which has a great potential, is important to design a low-carbon society.

ISSN: 2186-2311

Recently Japanese energy security has been unstable, therefore, it is an urgent task to propose an explicit scheme for improving energy security. The purposes of this study are threefold. First one is to establish a specific definition considering significant aspects of the energy security concept. Second one is to evaluate energy security quantitatively based on strategically selected criteria and the last one is to indicate a direction of energy policy towards a future highly secure energy supply system for Japan considering the economic feasibility by applying a multi-objective analysis. As a result, it is realized that the current energy system in Japan is inefficient from both energy supply cost and energy security perspectives, and the system is inferior compared to other developed countries. In order for Japan to improve its energy security level effectively, the expansion of the use of natural gas and renewable energy such as biomass is required.

The purpose of the study is to design a woody biomass energy system and application to coal co-firing, and to evaluate the system considering the three dimensions of energy, economic, and environmental impact. The study targets five types of woody biomass; forest wood residues, forest thinnings, sawmill wood residues, construction wastes and pruned branches of fruit trees. The system contains of collecting of biomass, transporting raw materials, producing wood fuels, transporting wood fuels, and coal co-firing. The study evaluates six cases that differ in wood fuel production location and the type of wood fuel. The results of case study show that the potential of the biomass resource is 37 PJ/year and the availability is 3.6 PJ/year in Tohoku area. The case that pellets produced at the resource generation points has the lowest amount of energy consumption 0.9 PJ/year, wood fuel supply cost 3.2 JPY/MJ and CO₂ emissions 0.66×10³ t-CO₂/year. It is also obtained that the drying process and transportation process have dominant effect on energy consumption and cost.

The purpose of this study is to design an optimum biogas cogeneration system considering spatial distribution of heat demand and biomass resource. In this research, mixed integer linear programming (MILP) is applied to design network layout for collecting biomass and supplying heat, and to optimize the operation strategy. To include spatial boundary constraint in this model, geographical information system (GIS) is used. The results indicate that district heating network connecting both single high demand site and residential buildings is optimal. In this case, energy profit ratio (EPR) becomes approximately 3.0 by use of poultry manure instead of sewage.

The purpose of this study is to design and analyze a woody biomass supply chain. Proposed supply chain consists of felling and collecting of a raw wood, pre-processing, and raw wood and wood fuel transport. In particular, the transport process includes two mobilities modes; three weight divided types of trucks, and railways. Applying mixed integer linear programming model provides optimal logging area, pre-processing plant location and capacity, and supply flow of raw wood and fuel. As a case study, we selected five prefectures with feasible forest in Tohoku area in Japan. Annual feasible amount of wood and shortest transport path are calculated with Geographic Information System (GIS). Optimized supply chain is evaluated in three dimensions; wood fuel supply cost, Energy Return on Investment (EROI), and Net CO_2 reduction amount. We examined three deferent cases, in the best case, 4 t truck, 10 t truck and 20 t truck can be used and unit supply cost of a pellet becomes 24,267 JPY/t as a result.

The purpose of this study is to evaluate the biomass energy system considering the effective utilization of resource for the fossil fuel substitution. Simple energy balance and energy return on investment (EROI) are used to conventional energy evaluation. However, the energy balance is depended on the system scale, and EROI cannot show the total system efficiency considering consumed biomass resource. In this study, the alternative evaluations are suggested. One is the effective utilization rate of resource that is defined as the energy balance divided by higher heating value (HHV) of biomass resource. Another is the fossil fuel substitution rate that is net substituted fossil fuel energy divided by HHV of biomass resource. As a case study, these values are evaluated using woody biomass, several types of preprocessing and energy conversion in Japan's Tohoku area. It is obtained that the effective utilization rate of resource and the fossil fuel substitution rate show the total system efficiency clearly, and how to improve the system efficiency.

As global energy demand increases, improving energy security is one of the main issues of energy related problems in Japan. Thus the purpose of this paper is to evaluate energy security quantitatively and imply the best energy resource mix for the Japanese sustainable energy system from the perspective of energy security with considering an economic perspective. This study is mainly divided into three parts; conceptualizing energy security, evaluating energy security through international comparisons, and obtaining pareto optimal solutions by solving a multi-objective analysis considering energy security and economic feasibility. GAMS is used for coding the multi-objective analysis called an augmented ϵ-constraint method (AUGMECON). The results show that the Japanese energy system has improved from 2000 to 2010 from the aspect of both energy security and supply cost, however, it is still inferior to those of other countries. In order to improve energy security, the increase of the use of renewable energy and natural gas instead of oil and coal is recommended, therefore, it is an urgent task to establish a stable supply system using renewable energy and expand high resilient gas pipelines.

Population and economic growth are expected to cause an increment of 37 % in world energy demand by 2040 and 60 % in food production by 2050. Simultaneously, rural population is abandoning farms, and cities are becoming mega cities. Therefore, a challenge of increasing agricultural land efficiency exists. Hence, a design of a multifunctional farm is proposed in this research, where food and energy is produced within farm boundaries. A linear programming model was developed with the objective of minimizing area, considering agricultural land and the area needed for energy technologies. A Business as Usual Scenario and another two were analysed. In Scenario 1 residues are feedstock of CHP and biofuel. Scenario 2 includes solar PV and wind turbines. A region in Japan was selected and compared with one in Colombia, in order to realise challenges for each. The results indicate that including different crops from the status quo could help achieving the goal of supplying high energy needs in less space; such is the example of cassava root in Japan for biofuel generation. If land use and crops are considered with the model proposed, biofuel production may not interfere with food security.

A Computable General Equilibrium (CGE) model has been developed and applied to Japan in order to analyze the economic impacts caused by the introduction of bioethanol produced from rice. Even though the analysis is done on a national level, the application of the model is regional. That is, Japan has been divided into nine geographical regions, and the model has been applied to each. For each region, a Social Accounting Matrix (SAM) has been prepared to be used as database for calibration of the model. Then, the introduction of bioethanol is simulated as a substitution of a fixed share of the petroleum sector using a penetration rate parameter. The model is then run for a wide range of this penetration rate parameter (from 5% to 100%) with the intention to cover all the common ethanol fuel mixtures. Results show that the major economic impact of the bioethanol introduction is on the rice sector, where the feedstock of the bioethanol comes from. This sector experiences an increase linearly proportional to the bioethanol penetration rate in its demand and price. Also, a negative economic impact on the food sector is observed, as it presents a decrease in its level of production due to the deviation of the rice now used to produce ethanol.

This paper aims to design the woody biomass supply chain for co-firing in the coal power plant. The woody biomass supply chain consists of 4 processes; Collection, Resource transportation, Preprocessing, and Fuel transportation. Preprocessing is divided into two processes such as Drying and Fuel production. Sawmill residue, construction waste, forest residue, thinning residue, and pruning of fruit tree are treated as raw material. Wood chip, pellet, and torrefied pellet called black pellet are treated as bio-fuel. The transportation of raw material and bio-fuel is optimized by using Geographical information system (GIS). As a case study, the woody biomass supply chain in Tohoku region is designed. The potential of raw materials is 37 PJ/year, and the availability is 3.6 PJ/year. As all resource is utilized in power plant, the lowest amount of energy consumption is 0.9 PJ/year that the all raw material is consumed to produce the pellet in resource generation points. And the lowest cost is 40,000 JPY/t of black pellets that are produced in resource generation points. It is obtained that the drying process and raw material transportation are dominant on energy consumption and cost.

The passenger amount of air transportation increased up to eight times during past 30 years. Due to the dramatically growth of aviation, CO₂ emissions from aircraft engine doubled during this period. Rapid growth of aviation sector would cause climate change, local air pollution and noise problem. In order to mitigate these environmental impacts of aviation, optimal aircraft operation is necessary. The goal for the research is set to formulate optimization model which can consider these environmental impact and to evaluate the mitigation by applying the model to domestic lines of Japan. This paper describes the airline fleet assignment problem including externalities of environmental impacts. The model explores optimal aircraft type, which minimizes social cost that is the sum of total operating cost and external cost of CO₂ and NO_x emissions. The results show optimal fleet assignment can mitigate environmental impact in some degree. However, it might be almost impossible to achieve the reduction target only by optimal fleet assignment.

In this study an exergy and exergoeconomic evaluation of a heat supply system paradigm of Japan and a district heating system (DHS) is conducted from a single user perspective, providing cost-based information on the systems inefficiencies and improvement potential. A heat supply system of a case city is used as a paradigm for Japan and a DHS is modelled according to standard practice for the same city, integrating geothermal heat and local waste sources. The local resources can supply 21% of the design load and natural gas is used for supplying the rest. For the analysis a pre-design exergy analysis tool combined with the specific exergy cost method is applied. The DHS and Japanese paradigm system have exergy efficiency of 4.2% and 5.4% respectively. Due to thermo-economic synergy effect however, the DHS has lower unit exergy cost of space heating and domestic hot water of 508$/GJ and 273$/GJ compared to 686$/GJ and 726$/GJ of the Japanese paradigm system. The DHS has considerable performance improvement potential through reduced operation temperatures and effective use of combustion sources through co-generation. The unit exergy cost difference leaves margin for capital investment cost increase for decreasing exergy consumption of the DHS.

It is necessary to improve the sustainability of the industrial sector in developing countries, particularly in the case of energy intensive industries. Energy efficiency improvement and fuel substitution with natural gas and low-CO2 electricity can reduce CO2 and pollutant emissions, energy losses, and improve working conditions. In this research, CO2 emissions reductions achievable with these two measures in non-ferrous metals secondary production and semi-fabrication were estimated; and the barriers that prevent their materialization discussed. A national scale bottom-up static linear programing optimization model was developed to assess the energy resource/end-use device allocation problem in non-ferrous metals secondary production and semi-fabrication; and used to study the case of Colombia, where low-CO2 electricity is available. Besides the base scenario, three alternative scenarios were considered, focusing on different priorities for decision making: (min. cost) minimizing total cost under energy resource and material demand constraints; (low CO2) minimizing CO2 emissions under energy resource and material demand constraints; and (min. CO2) minimizing CO2 emissions under energy resource constraints, except for natural gas and electricity, and material demand constraints. Results indicate that compared with current CO2 emissions of 62.5 kt-CO2/yr, minimum cost system configuration can achieve CO2 emissions as low as 17.7 kt-CO2/yr due to the improvement of energy efficiency; while the minimum CO2 emissions system configuration can achieve CO2 emissions as low as 7.7 kt-CO2/yr, using energy efficient electric devices; which are preferable over regenerative natural gas furnaces for electricity CO2 emission factors lower than 350 t-CO2/GWh. Similarly, pollutant emissions are also expected to decrease. Cost of CO2 avoided is negative in all the alternative scenarios, indicating the existence of ‘no-regret’ CO2 emissions reduction potential. Despite economic and environmental benefits of energy efficiency improvement and fuel substitution, it is considered that barriers such as uncertainty about energy resource price evolution, resource competition between energy use improvement projects and other projects, and lack of knowledge, among others prevent CO2 emissions reduction potential to be realized. Furthermore, it is necessary to improve the characterization of energy use in the industry with updated and detailed information, required to identify more accurately CO2 emissions reduction opportunities.

The largest increment in the global light-duty vehicle fleet in the medium- and long-term will happen in developing countries. Advanced vehicles can outweigh increments in CO emissions of a growing vehicle fleet; however, cost remains a barrier for their diffusion. A stock turnover model of the passenger car fleet was developed to estimate the potential of advanced vehicle deployment for CO emissions reduction, and used in the case of Colombia. Vehicle types included internal combustion engine vehicles (ICEVs), battery electric vehicles (BEVs) and fuel cell hybrid electric vehicles (FCHEVs); using two glider types: conventional and lightweight materials-intensive. Five scenarios were considered: the base scenario that relies on conventional ICEVs, and four alternative scenarios targeting the penetration of (A) BEVs, (B) BEVs and lightweight vehicles, (C) FCHEVs, and (D) FCHEVs and lightweight vehicles. Deployment of BEVs and lightweight vehicles offers the largest cumulative well-to-wheel CO emissions reductions, 22.01% compared to the base scenario; with cost of avoided CO going from 930USD/t-CO avoided in 2020 to 31USD/t-CO avoided in 2050. Despite advanced vehicle deployment, gasoline will be the main fuel and iron and steel the main materials until 2050 in the Colombian passenger car fleet. © 2014 Elsevier Ltd. 2 2 2 2 2 2

The main objective of this research is to develop a bottom-up energy-economic model considering endogenous technological development. The designed model analyzes the feasibility of CCS technologies in the Japanese electricity market to derive an optimum carbon reduction scenario. Two factors, a learning curve based on learning-by-doing and public R&D investment, precede technological progress. The analysis is calculated with a set of scenarios, which is based on alternative assumptions for technological characteristics: chemical and physical carbon absorptive technology. From modeling estimation, we conclude that technological progress reduces the generation costs of conversion technologies with CCS, as a CCS system acquires an additional unit of installation. Generation cost with chemical absorption remarkably reduces its marginal unit cost through a learning mechanism. The supply fraction from a gas-fired power plant increases over the analytical time period. The introduction of CCS reduces carbon emission level 17% compared to the baseline scenario in 2050. Technological progress has little impact on the total system costs; however, learning-by-doing pushes the introduction of CCS into the market rather than into a R&D activity. Research and development efforts in the private sector or knowledge spillover are not modeled in the study; however, they have the potential to contribute to the mitigation of carbon emission as well. © 2013 Wiley Periodicals, Inc.

本研究では，日本の電力部門をボトムアップ型の数理モデルで表現し，二酸化炭素排出量制約条件を考慮したコスト最小化問題を解くことにより，再生可能エネルギー発電技術への技術進歩の影響を明らかにする．技術進歩としてAEEIと二因子技術習熟を用いることで，主に政府等による研究開発の動向をモデルに内生化する．公的な研究開発投資予算に制約を課さない場合，二因子技術習熟によって，再生可能エネルギーの発電コストは最大で43％低減可能である．また公的な研究開発投資は，2050年にそのピークに達し，その後減少傾向に転じる．そのときの投資額は，2000年次の日本のエネルギー予算の約80％に相当する．

The paper examines the effects of research and development (R&D) on the capital cost reductions and the introduction of renewable energy technologies, namely solar photovoltaics (PV) and wind technologies. The proposed model in the study deals with the dynamics of technological learning. Functional form is a new kind of three-factor learning curve as a function of the cumulative capacity and the knowledge stock accumulated by public and private R&D expenditures. An econometric analysis is used to identify the influence of the knowledge stock on the capital costs of renewable energy technologies. Moreover, the study clarifies the relationship between the cost reductions and the market penetration. If the expenditures for public and private R&D in 2010 are fixed until 2050, then the model predicts that the capital costs of solar PV systems in 2050 become $1,750 /kW. Sensitivities of the annual R&D growth rate for the technologies are tested. The model also provides important results that the increase by four times of R&D budgets is necessary in order to reach the cost reduction targets by the Japanese government. The proposed methodology herein is helpful for decision makers to forecast how the costs of renewable energy technologies will change, and thereby providing the basis for R&D planning.

In recent years, municipalities have started to develop their own energy plan. Therefore, a quantitative evaluation approach considering energy demand distribution is of benefit. In foreign countries, energy maps which visualize the demand distribution have been used to make an effective decision regarding energy planning. Over the past few years, several studies have analyzed using energy maps, but this approach has not yet been conducted on rural areas which are rich in energy resources. This paper presents the method for making energy map for rural town and applying energy map for designing a biomass district heating system considering pipe network heat loss and pumping power demand based on heat demand distribution. The case study was done for Mogami-cho, Japan. The results indicate the case of DHS connected with both high demand commercial buildings and single detached houses is economically competitive. And, the introduction of biomass based district heating system is recommended in the area with linear heat density of 4.2 GJ/m.

The purpose of this research is to design an optimum automotive bioethanol supply chain in Japan. In this research, a mixed integer linear programming (MILP) model provides the optimal design of bioethanol supply chain with the objective of minimizing the cost of supply chain. Furthermore, the model can optimize biomass species, cultivation and traffic volume of biomass, locations and scales of the bioethanol production plants and traffic volume of bioethanol. The transportation cost of feedstock and bioethanol are optimized using Geographic Information System (GIS). Optimized supply chain is evaluated bioethanol production cost, energy profit ratio (EPR) and CO<SUB>2</SUB> reduction. Tohoku area was selected as a case study. The bioethanol production cost, which uses first generation bioethanol plant is 203 JPY/L, where first and second generation bioethanol plants are installed is 168 JPY/l, where first and second generation bioethanol plants are installed and technological development was considered is 92 JPY/L. EPR of each case are 1.66, 2.49 and 3.40, and CO<SUB>2</SUB> reduction are 277 kt-C, 288 kt-C and 305 kt-C, respectively. It is necessary to decrease cultivation cost of energy crops and increase bulk density of crop residue to reduce the bioethanol production cost, increase EPR and CO<SUB>2</SUB> reduction.

Bioethanol has great potential to reduce greenhouse gas emissions, improve energy security, and help revitalize agriculture. Accordingly, an E10 policy that substitutes bioethanol for 10% of all gasoline consumed will be globally popular. The present study aims to analyze the economic effects of bioethanol production for an E10 policy in nine ASEAN countries (except Brunei), with efforts to minimize CO₂ emissions. We consider two self-sufficient bioethanol production policies, i.e. self-sufficiency within each country and that within the ASEAN region under the scheme of a production quota. The optimization model, based on Takahashi et al.²⁰, and the inter-regional Input-Output Table, as estimated from the GTAP-7 (Global Trade Analysis Project, ver. 7) database, are used for consistent policy evaluation. The results demonstrated initially that the E10 policy under the scheme of a regional production quota elicited about 20% more environmental and economic effects than self-sufficient production within each country. Second, Singapore, Japan, China and the USA increased their production through bioethanol plant construction and annual production, even though this study assumed they did not increase bioethanol production. Approximately half the total induced production emerged in these countries. Third, induced production in agriculture accounted for half the total induced production. Based on these merits, several policy implications relating to the E10 policy with policy coordination are discussed.

Space heating and domestic hot water account for about 50% of residential and commercial sector energy consumption in relatively cold climates. This energy service demand is generally met by fossil fuels causing considerable amount of GHG emissions. In Japan the supply system is mainly constructed of small scale, distributed, building based conversion units being supplied by imported fossil fuels or electricity. In addition to being carbon intensive and almost completely dependent on imported fossil fuel, space heating in residential sector of Japan has been estimated to have energy and exergy efficiency of 99.8% and 4.6%. The low exergy efficiency indicates bad utilization of the available energy content of the supply fuel because of a mismatch between quality levels of the supply fuels and energy service demand. Fuel transition or restructuring of the heat supply system matching the quality level of the energy demand while fulfilling acceptable levels of availability, affordability and environmental impact is therefore of great benefit. District heating system is a flexible heat supply system that can integrate various local heat resources and has proven to supply heat in an effective and cost competitive way.<br /> The purpose of this study is to assess the feasibility of a district heating system integrating local, low carbon energy sources, providing space heating and hot water on a small-city scale as a comparison to conventional fossil fuel based heating system. Study area is Hirosaki city located in north of Japan with relatively high fossil fuel prices and high heat loads. An energy analysis of the existing system is conducted, disaggregating the consumption by type of fuel and type of energy service demand. The district heating system is designed in order to match peak load. Steady state thermoeconomic analysis considering peak load conditions is conducted for assessing and comparing the two systems. Performance and exergoeconomic parameters are used to evaluate and compare the systems. Available feasible resources in Hirosaki considered for the district heating system are waste wood, municipal solid waste incineration plant waste heat, sewage sludge and geothermal energy. Together they are able to provide about 17% of the peak load. The insufficiencies of local resources are assumed being supplied by natural gas boiler. Results indicate a considerable reduction in CO2 emissions and the thermoeconomic analysis indicates that low fuel cost and less exergy destruction compensate for the high capital investment cost required for transition to district heating system. Energy efficiency is higher of the reference system and exergy efficiency about the same for both systems at peak load.

Industrial sector growth in developing countries requires the provision of alternatives to guarantee sustainable development. Improving energy efficiency and fuel switching are two measures to reduce CO emissions in the industrial sector, with natural gas and low-carbon electricity as the most feasible options in the short term. In this work, a linear programming optimization model has been developed to study the potential of energy efficiency improvement and fuel substitution for CO emissions reduction, at national level in the non-ferrous metals industry. The energy resource/end-use device allocation problem in secondary metal production and semi-fabrication has been modeled. Using this model, the particular case of Colombia, where low-carbon electricity is available, has been studied. By improving energy efficiency, energy use and CO emissions can be reduced significantly, 73% and 72%, respectively, at negative costs. Further CO emissions reductions, up to 88%, are possible with fuel switching to low-carbon electricity, increasing the costs for the energy system; however, cost reductions caused by energy efficiency improvement outweigh cost increments of fuel switching. Benefits achieved with fuel substitution using low-carbon electricity can be lost if hydropower is not available; in such a case, efficient natural gas-fired end-use devices are preferable. © 2012 Elsevier Ltd. 2 2 2 2

Introduction of ZEVs (zero emission vehicles) and lightweight materials in a conventional steel-intensive internal combustion engine vehicle fleet will affect energy consumption and automotive material requirements. We developed a bottom-up dynamic accounting model of the light-duty vehicle fleet, including vehicle production and disposal, with detailed coverage of powertrains and automotive materials. The model was used to study the potential for energy consumption and CO emissions reduction of ZEVs and lightweight materials in the Colombian passenger car fleet from 2010 to 2050. Results indicate that passenger car stock in Colombia is increased by 6.6 times between 2010 and 2050. In the base scenario energy consumption and CO emissions are increased by 5.5 and 4.9 times respectively. Lightweighting and battery electric vehicles offer the largest tank-to-wheel energy consumption and CO emissions reductions, 48 and 61% respectively, compared to 2050 baseline values. Slow stock turnover and fleet size increment prevent larger reductions. Switching to electric powertrains has larger impact than lightweighting on energy consumption and CO emissions. Iron and steel remain major materials in new cars. Aluminum consumption increases in all scenarios; while carbon fiber reinforced polymer consumption only increases due to fuel cell hybrid electric vehicle or lightweight vehicle use. © 2012 Elsevier Ltd. 2 2 2 2

The purpose of this study is to assess the use of quality of energy in Iran's industrial sector. The exergy analysis has been performed along with energy analysis, in order to gain deeper and more realistic understanding of the sector's condition. Primary energy utilization from seventeen different industries has been considered for calculation of the exergy and energy efficiencies for each industry, and later for Iran's industrial sector. The exergy efficiency is much lower than energy efficiency in all industries and also in the industrial sector. It is shown that based on the results from exergy analysis the priorities for efficiency improvement are different from that of energy analysis; this in turn suggests that exergy analysis as a proper tool for policy makers. The sources of energy degradation and the mechanisms which cause degradation of quality of energy have been identified. Moreover remedial actions for better utilization of quality of energy are proposed. The energy and exergy efficiencies for the entire industrial sector of Iran were approximated as 63% and 42%, respectively. The oil, iron and steel, plastic and cement industries are found to have the highest share in destruction of quality of total input energy to the industrial sector. The aluminum industry has the highest exergy efficiency of 52.5%. Mean entropic temperature is also proposed as a tool for understanding the degree of quality of energy required in each industry and consequently better quality matching which leads to better energy quality utilization. © 2011 Published by Elsevier Ltd. All rights reserved.

Decentralized electrification using local resources can reduce regional disparity in rural and remote areas in terms of supply reliability and cost, as well as promote income generation. In this research an optimization energy model is introduced for designing decentralized energy systems using biomass for rural electrification in developing countries. Regional disparity is incorporated disaggregating electricity demand into urban, rural and remote areas. The model has been applied for designing a decentralized system using agricultural waste and forest biomass in a region in Colombia, South America. The resulting design includes biomass technologies in remote areas, reducing supply cost by 30% in this region. Using agricultural waste for electricity generation increases unit costs by 25% and reduces 15% of CO emissions compared to the current energy system. Using all biomass to meet current demand lowers the efficiency of the system, resulting in high system costs and emissions reduction. Reduction of disparity in electricity access among regions using local biomass needs to balance the increase in energy system costs and CO emissions reduction. For instance, using 30% of available biomass reduces 22% of system CO emissions, and provides 121USD/house/yr and 99 USD/house/yr of additional income in rural and remote areas, respectively. Design of the energy system considering regional disparity shows that fuel transportation costs and efficiencies of biomass conversion technologies have significant impact on system configuration and performance. © 2011 Elsevier Ltd. 2 2 2

The purpose of this paper is to present a new tool for design of integrated energy systems. The initial choice of the energy system components and the way they should interact is a crucial decision which the outcome of the design heavily relies on. Use of a physical law (instead of engineering judgment) as the basis of the decision making is the main advantage of the proposed approach over conventional approaches for design of community scale energy systems. The methodology has been implemented for design of a district heating system for an existing district in arid region of Iran. The optimum level of interaction between the energy system components has been identified by employing an optimization algorithm seeking to minimize the overall cost of the energy system. Some of the relative merits of the optimum design comparing to the present energy system are 17% increase of the exergy efficiency, 10.8% reduction in the amount of CO production per capita and 2% reduction in overall energy related costs. © 2011 Elsevier Ltd. 2

The purpose of this study is to design a biomass utilization system for different types of biomass resources, fuel production technologies, and energy conversion technologies. Evaluation of biomass utilization system has been studied considering single resource or technology. However, the evaluation methodology for different resources and technologies is not established yet. In this study, the biomass energy system has been modeled and integrated for several types of biomass resources and technologies. The system consists of 4 processes; Resource, Fuel Production, Energy Conversion, and Waste treatment. By using this model, energy balance, CO_2 emission, economic impact of the biomass energy system can be evaluated.

The purpose of the research is to design an automotive bio-fuel supply chain considering economic and social aspects in Japan, and to evaluate its total cost, energy balance and CO_2emission. In this research, mixed integer linear programming (MILP) models make optimal design of bio-fuel supply chain with the objective of minimizing the total supply chain cost. The model can optimize biomass species, locations and scales of the bio-fuel production plants. The target of this case study is Tohoku area. In the case study, bio-ethanol from imported feed stock has price competitiveness with gasoline. Net energy balance and net CO_2 reduction of the supply chain using domestic feed stock is positive.

Recently, the microalgae that can produce fats and hydrocarbons attracts a lot of attention as means to solve the issue of global warming. The purposes of this study are to design microalgae-based biodiesel fuel (BDF) production system using exhaust gas from thermal power plants and considering regional characteristics, and to analysis potential of the microalgae from the viewpoint of energy balance, CO<SUB>2</SUB> balance and fuel production cost. The system consists of five components: Culture, harvesting, extraction, transportation, conversion. In addition, the methodology of this study has three processes: Allocating microalgae culture plants and BDF production plants, optimizing transportation using Geographic Information System (GIS) with Network Analyst, and evaluating energy balance and CO<SUB>2</SUB> reduction of the system. Besides, to minimize BDF production cost, we change the number of BDF production plants and consider trade-off between transportation cost and BDF production plants costs. The result shows that microalgae-based BDF production system has high potential for CO<SUB>2</SUB> reduction and the possibility to competitive with the fossil fuel cost.

In the production of bioethanol in Asia, developed countries such as Japan have the problems of high cost and a lack of resources, while Southeast Asian countries have substantial biomass production and export potential. The purpose of this study is to optimize the international supply of bioethanol in East Asia. A linear model is developed to estimate costs, energy consumption, and carbon emissions in three processes: cultivation, conversion, and international transport. In order to consider the regional characteristics of producing countries, biomass price, electric power generation, fertilizer usage, agricultural machine usage are incorporated into the model. Optimization based on linear programming is carried out with two objective functions: minimizing cost and minimizing carbon emissions. For each objective function, the amount of supply, economic efficiency, and carbon emissions are quantitatively analyzed in three cases. One is domestic supply case where each country supplies bioethanol to domestic market. Another is Asia supply case where Asian countries supply bioethanol with international supply. The other is Asia-Brazil supply case where Brazil is included in bioethanol supply in Asia. The average supply cost of bioethanol in Asia supply case with the objective function of minimizing cost is a quarter of that in domestic supply case. The carbon emissions reduction increases by international supply. Brazil has more than 50 % share in bioethanol production in both objective functions and contributes to the reduction of carbon emissions.

Storing municipal solid waste (MSW) in landfills is the oldest and still the primary waste management strategy in many countries. Russia is the third largest methane (CH4) emitter country after USA and China, representing 5% of total global CH4 emissions from waste landfilling. Due to high economical growth, the amount of waste generated in Russia has risen sharply over the last ten years. However, waste management in Russia is mainly based on landfilling. In order to design an optimal MSW utilization system considering various aspects related to sustainable MSW management, a linear programming model was introduced for this research. The performance of the proposed MSW utilization system in the target area has been evaluated in light of energy, economic, and environmental (3Es) aspects, such as system net cost, annual energy generated from the waste, and the carbon dioxide (CO ) emissions of the system. St. Petersburg city was considered as the target area for the present analysis. The results show that the introduction of the proposed MSW system with energy recovery from waste along with a high level of material recovery has energy, environmental and economic benefits compared to the conventional treatment system. This paper emphasizes the importance of introducing waste treatment methods as an alternative to landfilling, and to improve recycling activities in Russia. © 2011 by the authors. 2

This paper describes several benefits of the integration of designed optimal municipal solid waste (MSW) utilization system considering energy recovery options and present energy system. A linear programming model has been developed in order to analyse proposed municipal solid waste system, taking into account the 3E's (energy, economic, and environment) aspects. The objective function of the model is to minimize the net cost of the system, under several constraints. A case study in St.Petersburg city, Russia, has been carried out for evaluation of proposed the MSW system. The results show that the introduction of an optimal MSW utilization system has energy, environmental and economic benefits compared with the present system. The proposed integrated system can produce 1,900 GWh/year of heat or 542 GWh/year of electricity in average, which can be supplied to the existing energy system. In addition, the system can reduce the amount of landfilled waste from 89% to 20%, and reduce total system's CO₂ emission by more than 70%.

The main objective of the research is to develop a bottom-up energy-economic model considering endogenous technical progress, and to analyze the potential of CCS introduction among Japan's electricity market in order to find out an optimum carbon reduction scenario into the future. On the basis of two-factor learning curve, both learning-by-doing and R&D functions drive technical progress in the model. The analysis is performed with a set of scenarios based on alternative assumptions for technical progress of carbon capture technologies: chemical absorption and physical absorption. As a result, technical progress decreases generation costs of power technologies with CCS systems resulting in the acceleration of additional CCS introduction. In addition, generation cost with chemical absorption notably decreases due to technical progress, and share of gas-fired power plant in total power generation increases. Thus, carbon emissions reduction reaches around 17% of total carbon emissions in 2050 under projected scenario, however, technical progress has little impact on total systems cost. Technical progress by learning-by-doing has a strong impact on CCS introduction than that of R&D. Moreover, unconsidered factors such as R&D effort in private sectors and spillover may push down possible carbon emissions as well.

This paper examines the effects of R&amp;D on the introduction of PV systems with technological learning in Japan. The proposed model in this study describes how the costs of PV modules are affected by the technological knowledge stock accumulated by university, industry and government R&amp;D expenditures. Moreover, this study clarifies the relationship between the cost reductions of PV modules and the market penetration of PV technologies. The focus in this analysis is on the capital costs of PV modules, rather than on the costs of electricity produced, to exclude influential but exogenous factors such as interest rates.

Rising concern about the effect of greenhouse gas (GHG) emissions on climate change is pushing national governments and the international community to achieve sustainable development in an economy that is less dependent on carbon emitting activities - a vision that is usually termed a "low-carbon society" (LCS). Since the utilization of energy resources is the main source of GHG emissions, restructuring current energy systems in order to incorporate low-carbon energy technologies is essential for the realization of the LCS vision. Energy policies promoting the penetration of these technologies must view the role of energy in society as a system, composed of several energy resources, conversion technologies and energy demand sectors. The feasibility of the LCS in the future can be better understood by means of energy models. Energy models are valuable mathematical tools based on the systems approach. They have been applied to aid decision-making in energy planning, to analyze energy policies and to analyze the implications arising from the introduction of technologies. The design of the LCS requires innovative energy systems considering a trans-disciplinary approach that integrates multi-dimensional elements, related to social, economic, and environmental aspects. This paper reviews the application of energy models considering scenarios towards an LCS under the energy systems approach. The models reviewed consider the utilization of waste for energy, the penetration of clean coal technologies, transportation sector models as a sample of sectoral approaches, and models related to energy-for-development issues in rural areas of developing countries. © 2010 Elsevier Ltd. All rights reserved.

Biomass is getting the great interest in Japan, and the cabinet approved " Biomass Nippon Strategy" in 2002 to promote the utilization of biomass. Although various projects utilizing wood biomass for energy uses have started already, many of them utilize mainly waste wood. Forest biomass remains unutilized because of the high logistic cost and the small scale of resource generation at a site. Small-scale gasification is considered as a suitable technology for forest biomass, and more than 10 demonstration plants have started to be operated recently. This study analyzes the economic feasibility of the small-scale forest biomass CHP system with gasification technology in Japan.The authors have developed the BiRReT tool, which takes input data such as geographical resource distribution and scale merit information of the target technology, and analyzes the economics of bioenergy system in target region by finding the optimal conditions; namely plant size, plant location, the number of plants, and lower generation costs. A case study in Miyagi prefecture revealed the conclusion that the system with logging residue fuel has the economic feasibility if the capital cost and the resource price will decrease from the BAU case by technological learning in the future. On the other hand, thinned wood will not be utilized as a fuel for power plants due to high fuel production cost. It is also found by the tool analysis that the technology's scale merit has stronger impact on power generation cost in the trade-off between scale merit and the transportation cost. © 2011 Elsevier Ltd.

The study aims to evaluate the potential of GHG (greenhouse gas) reductions by installing an anaerobic digester in a wastewater treatment facility in Southeast Asia. Then the break-even point of additional investment to reduce GHG is obtained by exchanging carbon price as emissions credits. In the project scenario, the wastewater treatment system has the digester, where methane (biogas) is produced and recovered. Compared with the baseline scenario, the biogas has calorific value to produce heat and electricity, and can substitute fossil fuels for power generation. The objective of the study is to define the relationship between CERs (certified emission reductions) and investment costs, and the beak-even point, finding out the dominant parameters in the system. Financial parameters such as capital costs and operating costs are considered to evaluate the investment costs. The result shows that the methane recovery reduces 54% of GHG emissions. Although the substitution of the biogas for the fossil fuels reduces only 6% of the GHG emissions, the electricity output can satisfy the electricity consumption. The results also show that the maximum CER credit is 73000 t-CO e/a, and the GHG reduction cost is 14 USD/t-CO e. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg. 2 2

In this study, 13 types of sewage energy system are evaluated by using inventory analysis. Evaluation indexes are energy balance, greenhouse gas emission, and economic efficiency. The main equipment of those energy systems are three types of incineration, three types of solid fuel, two types of pyrolysis gasification, and five types of digestion. The range of evaluation is from sewage sludge to power generation. Inputs of those energy systems are electricity, city gas, light oil, and wood biomass, and outputs are production of electricity, CO<SUB>2</SUB> gas, and N<SUB>2</SUB>O gas. The results from the viewpoint of energy balance show that only the systems with gasification furnace produce larger electricity generation than total consumption. The results about the greenhouse gas emission show that the lowest gas emission system is the system with solid fuel produced by drying. N<SUB>2</SUB>O gas emitted by solid fuel is lower than the others. The results about the economic efficiency show that the lowest cost system is the systems with solid fuel because the construction cost that holds most of total cost is much lower than the other systems.

Bio-ethanol (BE) plays an important role in the reduction of greenhouse gas (GHG) emissions. Since East Asian countries face different economic and political situations and are located under different climatic conditions, GHG emissions, production costs and materials available for BE production differ, it is crucial to optimize production and trade of BE among East Asian countries by coordinating policies. This paper aims to show the economic merits of a policy coordination scheme for BE production and trade.<br> The East Asian inter-regional I/O table was estimated from the GTAP (Global Trade Analysis Project, ver. 7) database to calculate production induced by investment for plant construction and working expenditure of annual production. Two different scenarios, the self-sufficient production scenario and policy coordination scenario, were considered to achieve an E10 policy with minimization of total CO2 emissions. In each scenario, an optimal level of production and trade quantity were calculated by a linear programming model (Takahashi, et al., 2010).<br> The simulation results demonstrated that, first, the policy coordination scenario yielded a higher production as a benefit in the whole region than the self-sufficiency production scenario. Second, Japan and the USA greatly benefited from policy coordination even though the amount of their BE production increase was small. This is because these countries provide production machinery for plant construction and chemical materials for BE production. Third, BE production under policy coordination contributed to promoting pro-poor growth in the least developed countries such as Cambodia, Laos, Myanmar and Vietnam by improving agricultural production.<br> Therefore, policy coordination for BE production and trade is a beneficial idea for development of East Asian countries. Particularly, Japan as a member of East Asia should take an initiative by investing money. In addition, the inter-regional I/O analysis employed in this study is useful for showing the benefits to policy makers.<br><br>JEL Classification: C67, Q27, Q28, Q58, Q54

Estimating technological progress of emerging technologies such as renewables and clean coal technologies becomes important for designing low carbon energy systems in future and drawing effective energy policies. Learning curve is an analytical approach for describing the decline rate of cost and production caused by technological progress as well as learning. In the study, a bottom-up energy-economic model including an endogenous technological learning function has been designed. The model deals with technological learning in energy conversion technologies and its spillover effect. It is applied as a feasibility study of clean coal technologies such as IGCC (Integrated Coal Gasification Combined Cycle) and IGFC (Integrated Coal Gasification Fuel Cell System) in Japan. As the results of analysis, it is found that technological progress by learning has a positive impact on the penetration of clean coal technologies in the electricity market, and the learning model has a potential for assessing upcoming technologies in future. © 2010 Elsevier Ltd.

The purpose of this study is to evaluate GHG emission reduction and economic potential of wastewater treatment system by installing an anaerobic digester in Southeast Asia. Then the optimal investment to get GHG emission credit is obtained. In the advanced scenarios, the anaerobic digester is installed in the wastewater treatment system, and methane (biogas) is recovered and combusted. The biogas can be utilized for electricity generation and heat production, and can substitute fossil fuels. The objective of the study is to define the relationship between CER (certified emission reduction) credit and investment costs, and the optimal system by the calculation Internal Rate of Return (IRR). The result shows that the methane recovery and destruction reduces 63 % of GHG emissions from BAU scenario. The biogas utilization for energy has small effect on the GHG reduction. However, the income by energy production has large effect on the IRR. Thus, the IRR in the case that all biogas is utilized for electricity generation is 24%, and the IRR in the case that all biogas is utilized for heat production is 8%. The results of sensitivity analysis also show that the dominant parameter to increase IRR is capital cost. If the capital cost for heat production is half, the IRR is more than 40%.

Bioethanol is expected as a prospective alternative to fossil fuels for mitigating greenhouse gas emissions. The study aims to design bioethanol production system utilizing energy crops in restorable fallow land in Japan and evaluate system performance based on energy balances, costs, and carbon emissions. The energy system has three processes such as cultivation, transportation, and manufacturing. In the analysis, energy potential in the area is calculated considering crop species, yields, chemical components, available land areas, and conversion efficiency. Then, the system performance is derived focusing on a local prefecture as a case study. The result shows that sorghum is expected to have the highest energy potential in most regions except for northern prefectures, and the amount of bioethanol produced from crops in fallow land is estimated to be about 2 million kl. Net energy value reaches -1.09 to 15.9 MJ/l. The total cost producing bioethanol is 2.4 to 8.9 times higher than petroleum fuel on calorific value basis. It is concluded that it is important to improve the productivity of the cultivation process of energy crops and to design optimized energy system to meet social requirements in near future.

Biomass resources have huge potential to secure energy supply in next decades with carbon neutral emissions. However, the resources itself are widely scattered diffusely throughout the country, and the capacity of utilization plant highly depends on the quantity of primary resources available. The study focuses on the equilibrium between resource supply and energy demand in Tohoku area in Japan, considering geographical distribution and transportation paths. Woody biomass and agricultural residues are introduced in the study as a co-firing fuel supplied to three coal power stations in Tohoku area. The biomass energy system is modeled and analyzed using both geographic information solver and the roadway condition data. In particular, resource supply such as biomass resource collection, preprocessing before transportation, storage, long distance transportation, and energy conversion to electricity, is modeled and introduced to the system. As a result of the model analysis, a supply curve of biomass resources is obtained, which shows a relationship between procurement cost for power supply and annual electricity production at coal power stations. The supply curve shows that an electricity of 4.3 &times; 108 kWh/yr can be supplied with the procurement cost of 10 JPY/kWh, and the maximum electricity reaches 12.7 &times; 108 kWh/yr with the procurement cost of 14 JPY/kWh.

Concern about global warming calls for an advanced approach for designing an energy system to reduce carbon emissions as well as to secure energy security for each country. Conventional energy systems tend to introduce different technologies with high conversion efficiency, leading to a higher average efficiency. Advanced energy systems can be achieved not by an aggregate form of conversion technologies but by an innovative system design itself. The concept of LCS (low carbon society) is a unique approach having multi-dimensional considerations such as social, economic and environmental dimensions. The LCS aims at an extensive restructuring of worldwide energy supply/demand network system by not only replacing the conventional parts with the new ones, but also integrating all the necessary components and designing absolutely different energy networks. As a core tool for the LCS design, energy-economic models are applied to show feasible solutions in future with alternatives such as renewable resources, combined heat and power, and smart grid operations. Models can introduce changes in energy markets, technology learning in capacity, and penetration of innovative technologies, leading to an optimum system configuration under priority settings. The paper describes recent trials of energy models application related to waste-to-energy, clean coal, transportation and rural development. Although the modelling approach is still under investigation, the output clearly shows possible options having variety of technologies and linkages between supply and demand sides. Design of the LCS means an energy systems design with the modelling approach, which gives solution for complex systems, choices among technologies, technology feasibility, R&D targets, and what we need to start. © 2010 Science in China Press and Springer Berlin Heidelberg.

Rural electrification with renewable energy technologies (RETs) offers several benefits to remote areas where diesel generation is unsuitable due to fuel supply constraints. Such benefits include environmental and social aspects, which are linked to energy access and poverty reduction in less-favored areas of developing countries. In this case, multi-objective methods are suitable tools for planning in rural areas. In this study, assessment of rural electrification with renewable energy systems is conducted by means of goal programming towards fuel substitution. The approach showed that, in the Non-Interconnected Zones of Colombia, substitution of traditional biomass with an electrification scheme using renewable energy sources provides significant environmental benefits, measured as land use and avoided emissions, as well as higher employment generation rates than diesel generation schemes. Nevertheless, fuel substitution is constrained by the elevated cost of electricity compared to traditional biomass, which raises households' energy expenditures between twofold to five times higher values. The present approach, yet wide in scope, is still limited for quantifying the impact of energy access improvements on poverty reduction, as well as for the assessment of energy system's technical feasibility. © 2009 Elsevier Ltd. All rights reserved.

The purposes of this research are designing co-combustion system using woody biomass and agricultural residue in Tohoku area. This research has five processes: Developing GIS database of available amount of biomass and their distribution, designing biomass procurement and co-firing system including collecting, storage, preprocessing, and transportation of biomass, optimizing transportation distance using GIS network analysis, defining procurement range of each biomass considering two types of economic constraint boundary, evaluating amount of power production, economic feasibility, and CO_2 reduction effect of total system. Co-firing system has high potential for RPS.

This paper discusses policy instruments for promoting the market penetration of clean coal technologies (CCTs) into China's electricity sector and the evaluation of corresponding effects. Based on the reality that coal will remain the predominant fuel to generate electricity and conventional pulverized coal boiler power plants have serious impacts on environment degradation, development of clean coal technologies could be one alternative to meet China's fast growing demand of electricity as well as protect the already fragile environment. A multi-period market equilibrium model is applied and an electricity model of China is established to forecast changes in the electricity system up to 2030s. Three policy instruments: SO emission charge, CO emission charge and implementing subsidies are considered in this research. The results show that all instruments cause a significant shift in China's electricity structure, promote CCTs' competitiveness and lead China to gain great benefit in both resource saving and environment improvement. Since resource security and environment degradation are becoming primary concerns in China, policies that could help to gain generations' market share of advanced coal-based technologies such as CCTs' is suitable for the current situation of China's electricity sector. © 2008 Elsevier Ltd. All rights reserved. 2 2

This research develops an energy-economic model with endogenous technological change. This model assumes a decrease of specific capital cost and O&M cost from technological change, and considers that technological experience is shared among the same component technologies. Furthermore, feasibility of CCS in Japan's electricity sector is analyzed. The analysis is performed based on scenarios with alternative assumptions over technological change of CCS component technologies; carbon capture, transport, and injection technologies. As a result, technological change doubles CCS potential, and generation technologies with CCS can produce 10% of total power generation in 2030. In addition, CO reduction from CCS introduction is increased by half, and 16% of carbon emissions in 2030 are reduced. CCS introduction increases the total system cost by 3%. Technological change has little influence on the total system cost. Aggressive R&D effort for CCS might push reduction by 20% of carbon emissions in 2030. 2

The purpose of this study is to reveal relations between access to electricity and advancement in a socio-economic condition in rural areas of developing countries. Recently, multi-dimensional aspects of poverty, for example, economy, education, and health, has been increasingly focused on, and access to modern energy such as electricity is one possible solution. As a case study, we have analyzed unelectrified rural areas in Assam state, India. We have developed an energy-economic model in order to analyze the possibility of electrification through dissemination of electric lighting appliances as well as applied multiple regression analysis to estimate the socio-economic condition, a literacy rate above 6 years old, in the areas. As a result of the case study, the household electrification rate, the 1000 km road density, and sex ratio have been chosen as the explanatory variables of the literacy rate. Moreover, the model analysis shows that complete household electrification will be achieved by the year 2012. In combination with the multiple regression and model analysis, the literacy rate in Assam may increase to 74.4% from 63.3%. © 2008 Elsevier Ltd. All rights reserved. 2

Purpose - This study aims to present preliminary results from an integrated evaluation of electricity supply systems for rural areas using renewable energy technologies by means of a multi-objective decision making method Design/methodology/approach - Goal programming is applied to obtain the optimal system configuration meeting the electricity demand, based on the location's resource availability and taking diesel generation as the alternative of reference. The performance of the system is evaluated through four attributes: electricity generation costs, employment and two environmental impacts (CO emissions and land use). The model is designed for isolated rural area belonging to the non-interconnected zones of Colombia. Findings - Application of the method showed that biomass conversion technology has the highest potential and that renewable energy systems offer better performance than diesel generation. Reductions of more than 10 percent in unit electricity costs, land use rates and CO emissions can be achieved. Research limitations/implications - Inclusion of additional attributes and sensitivity analysis are matters of future research. Originality/value - The methodology used in this study is an alternative means to perform evaluation of electricity supply systems integrating several aspects of technology and which is flexible enough so as to enable the inclusion of a wider scope of interests towards energy access targets. 2 2

This study examines the economics of energy-efficiency strategies for reducing CO emissions in the residential sector in Japan from the perspective of regional characteristics. For this study, the residential sector in Iwate prefecture was selected as representative of rural areas in Japan. In order to promote purchases of energy-efficient consumer appliances, the prefectural government is presumed to reimburse purchasers a part of the cost difference between energy efficient and conventional appliances. This paper begins with a discussion of the prefecture's financial support for purchasers of energy efficient appliances and assumes that the payments come from prefectural government funds. This paper then looks at the effect of a carbon-tax refund on the reduction of CO emissions. The results show that, if half of the households use energy-efficient appliances, then CO emissions in the residential sector in the year 2020 will decreases from the BAU scenario, 0.726 Mt-C to 0.674 Mt-C. However, the Iwate prefectural government expends $105 million annually, which is 1.5% of the total tax revenue in the year 2003. The carbon-tax refund effectively encourages further reductions in CO emissions. Under the $20/tC carbon tax, proposed by the Ministry of the Environment, the carbon-tax refund leads to a reduction in residential CO emissions from 0.726 Mt-C to 0.712 Mt-C. © 2007 Elsevier Ltd. All rights reserved. 2 2 2 2 2

The advantages of coal are the largest reserves among any other fossil fuels, and can be found in many places including some developed countries. Due to the weak energy security of Japan, it is necessary to use coal as an energy source. We have designed the detailed energy model of electricity sector in which we take both energy conversion efficiency and economic aspects into consideration. The Japan model means an energy-economic model focusing on the structure of the energy supply and demand in Japan. Furthermore, the most suitable carbon capture and storage (CCS) system consisting of CO₂ collection, transportation, storages are assumed. This paper examines the introduction of clean coal technologies (CCT's) with CCS into the electricity market in Japan, and explores policy options for the promotion of CCT's combined with CCS. We have analyzed the impacts of carbon tax where each fossil technology, combined with CCS, becomes competitive in possible market. CO₂ mitigation costs for all plants with CCS are detailed and compared.

In order to design optimal biomass utilization system for rural area, OMNIBUS (The Optimization Model for Neo-Integrated Biomass Utilization System) has been developed. OMNIBUS can derive the optimal system configuration to meet different objective function, such as current account balance, amount of biomass energy supply, and CO₂ emission. Most of biomass resources in a focused region <i>e.g.</i> wood biomass, livestock biomass, and crop residues are considered in the model. Conversion technologies considered are energy utilization technologies <i>e.g.</i> direct combustion and methane fermentation, and material utilization technologies <i>e.g.</i> composting and carbonization. Case study in Miyakojima, Okinawa prefecture, has been carried out for several objective functions and constraint conditions. Considering economics of the utilization system as a priority requirement, composting and combustion heat utilization are mainly chosen in the optimal system configuration. However gasification power plant and methane fermentation are included in optimal solutions, only when both biomass energy utilization and CO₂ reduction have been set as higher priorities. External benefit of CO₂ reduction has large impacts on the system configuration. Provided marginal external benefit of more than 50,000 JPY/t-C, external benefit becomes greater than the revenue from electricity and compost etc. Considering technological learning in the future, expensive technologies such as gasification power plant and methane fermentation will have economic feasibility as well as market competitiveness.

This study examines the economics of energy-efficiency strategies, for reducing CO emissions in a residential sector in Japan, from the perspective of regional characteristics. For this study, the residential sector in the Iwate prefecture was selected as representative of rural areas in Japan. In order to promote the purchases of energy-efficient consumer appliances, the prefectural government is presumed to reimburse purchasers a part of the cost difference between energy-efficient and conventional appliances. This paper begins with a discussion of the prefecture's financial support for purchasers of energy-efficient appliances and assumes that the payments come from prefectural government funds. This paper then looks at the effect of a carbon-tax refund on the reduction of CO emissions. The results show that, if half of the households use energy-efficient appliances, then CO emissions in the residential sector in the year 2020 will decreases from the BAU scenario of 0.726 Mt-C to 0.674 Mt-C. However, the Iwate prefectural government expends $105 million annually, which is 1.5% of the total tax revenue for the year 2003. The carbon-tax refund effectively encourages further reductions in CO emissions. Under the $20/tC carbon-tax, proposed by the Ministry of the Environment, the carbon-tax refund leads to a reduction in residential CO emissions from 0.726 Mt-C to 0.712 Mt-C. © 2007. 2 2 2 2 2

Since the law for concerning the appropriate treatment and promotion of utilization of livestock manure has come into effect in 2004 in Japan, the way of disposal of the manure causes serious waste management problem in rural areas. Production of biogas from the manure by anaerobic digestion is one of the promised technologies to reduce the amount of environmental effect, and to generate heat and electricity. Recently biogas power plants have been installed in rural areas, however, studies on the optimal allocation considering geographic distribution of livestock manure have hardly been investigated. The paper focuses on the optimal allocation of centralized biogas power plants and composting plants considering the distribution of the animal livestock at lower costs, introducing an optimization model and geographical information system. The study also analyzes the effect of the subsidy rate for construction cost on the optimal location of biogas power plants and composting plants.

Thailand's rate of energy consumption has been growing at a fast pace due to its economic development with a corresponding rapid increase in CO emissions. Given the widely accepted fact between CO emissions and climate change, mitigation policies in Thailand become an essential part. The analysis is aimed at studying the effects of Thailand's CO emissions mitigation options on the energy system and at determining the possible CO emissions reduction. In the paper we analyse that the imposition of a carbon tax in the region $20/tonC could reduce CO emissions by 5% up to the year 2020. Copyright © 2007 Inderscience Enterprises Ltd. 2 2 2 2 2

With nearly 10 % annual economic growth in the past two decades, China has already become the world’s second greatest energy consumer. While coal, accounting for 70 % of energy demand mix and 90 % of thermal electricity power generation by 2005, will continue to be the most important energy resource in China for a long time. How to meet the rapidly growing demand of electricity as well as considering the global need of mitigation of greenhouse gas (GHG), and eliminating other harmful pollutants due to conventional coal combustion such as SO2, NO2 and PM, will be a huge challenge to Chinese government. Integrated coal gasification combined cycle (IGCC) power plant is emerged as an attractive option for both economic development and environment improvement.<br /> This research aims to evaluate the penetration of IGCC into China’s electric sector by considering the externalities. A multi-period market equilibrium model (META・Net approach) is applied and an energy model of China is established to forecast changes in the energy system up to the year 2032. Two scenarios are designed: Business as usual (BAU) scenario, Internalizing External Cost (IEC) scenario where external costs of conventional coal power plants are internalized and 15 % of IGCC’s capital cost is subsidized.<br /> From the analysis, following results are obtained. IGCC does not penetrate into the market in a large scale in BAU scenario due to its relatively high capital cost. Moreover, results in IEC scenario indicates that by considering the external costs of conventional coal power plants and subsidy, IGCC gains much competitiveness in the electricity sector. Moreover, penetration of IGCC has great effect on emission mitigation. According to the results, it is revealed that IGCC will become an important technology for generating electricity in China and considering the externalities could be a considerable policy option for IGCC’s market penetration.

Utilization of woody biomass represents an effective alternative to fossil fuels for mitigation of global warming. The purpose of the study is to design woody biomass energy system, and to analyze the effect on the total cost of the energy system and environmental impact derived by installing biomass power plant in rural area in Japan. The energy system consists of woody biomass, logistics, energy conversion, and distribution of both electricity and heat. In order to analyze the comprehensive network of the system, an energy-economic model is developed and applied for the rural area. The model considers the balance between energy conversion sectors and energy demand sectors in long-term taking into account the cost of biomass power generation, price of conventional energy, legal issues, and limits of quantity of biomass supplied in target area. In addition to the feature mentioned above, the energy-economic model derives the cost minimum configuration of the energy system because an open market is supposed in the energy model. As the conversion technology of biomass, direct combustion power plant, and gasified power plant are set in the energy conversion part in the woody biomass energy system; the economic and technological performance of the biomass power plants is evaluated circumstantially. A major issue of preventing woody biomass from the smooth installation is the high cost of biomass resource. Hence, the subsidy is supposed for decreasing the cost of woody biomass in the study, and the effect of the subsidy on the total cost and amount of woody biomass used in the energy system are also evaluated.

Access to modern energy is one of the most basic requirements for development. In rural areas of developing countries, there are a large number of people who do not have access to LPG and depend on traditional biomass such as wood, crop, and dung for cooking. In addition, energy has numerous and complex links with poverty reduction. Therefore, it is important to estimate the impacts of energy access improvement on socio-economic situation in the rural areas of developing countries quantitatively. This study focuses on socio-economic impacts of cooking demand through changes in stoves adopted by the rural households. We have developed an energy-economic model of rural areas in India to analyze the links between energy, income, and health hazard, applying both opportunity cost for using fuelwood and exposure to Resipirable Suspended Particulate Matter (RSPM). As a result of the analysis, there is a positive relation between the opportunity cost and the average RSPM exposure of women in the rural areas. Following to increase in the opportunity cost, that is, income, the cost of an improved wood stove becomes relatively lower first than that of a traditional wood stove, and then a gas stove attains price competitiveness. It is achieved that the average RSPM exposure is below the WHO and Japanese criteria for Suspended Particulate Matter (SPM), 190 and 100 [μg/m ], at the opportunity cost of US$9 and 15/GJ, respectively. © 2006 Elsevier B.V. All rights reserved. 3

A linear optimization model to design livestock manure disposal system has been developed. The model can design the most economically efficient disposal system under the restriction of nitrogen supply, which has to be less than nitrogen demand in agricultural land to prevent water and land pollution. The livestock manure considered in the model are dairy cattle, beef cattle, swine, and poultry excreta. The disposal facilities considered here are composting, carbonization, wet methane fermentation, dry methane fermentation and poultry manure boiler. The optimization model has been applied for case study focused on Tome-city with four scenarios, such as scenario 1; reference case, scenario 2; subsidy for biogas plant case, scenario 3; facilitation of organic fertilizer utilization case, and scenario 4; combination of scenario 2 and 3. In the reference case, because of low demand for organic fertilizer, much of the live stock manure is processed in carbonization facility and not utilized as compost or liquid fertilizer. The result indicates that the facilitation of organic fertilizer utilization is the best policy option to maximize economic efficiency. Moreover, the combination of subsidy for biogas plant and facilitation of organic fertilizer utilization is the best policy option for energy utilization of livestock manure.

Small-scale wood biomass gasification is considered as a suitable technology to utilize forest biomass such as logging residue and unused thinned wood. Recently, more than 10 demonstration plants have started to operate to verify both technical and economic feasibility of the system. This study analyzes the economic aspect of gasification system focusing on the regional distribution of biomass resources and technical characteristics such as scale merit.<br>The authors developed BiRReT tool, which conducts the economic analysis of biomass energy system in a local region by finding the optimal conditions, namely plant size, plant location, and the number of plants. Case study in Miyagi prefecture had been carried out. Firstly, the economics of gasification system is compared with the steam-turbine-based CHP system that utilizes grate or fluidized-bed combustion technology. The result shows that gasification system has strong advantage in terms of low fuel transportation cost. Secondly, the economic feasibility of the system in a region is analyzed. The system with logging residue fuel has the possibility to gain economic competitiveness if technology learning and cost reduction will be seen in the capital cost and the fuel production process. Thinned wood will not be utilized only for the energy purpose.

The purpose of this study is to analyze the economical efficiency of biofuel in the transportation sector of Japan. In the study, we considered several kinds of energy crops which are harvested in fallow land. At first, biofuel potential in fallow land was calculated from regional climate, yield, mineral and cultivating cost. Then we have analyzed the impact of transport cost and scale merit of the biofuel factory. In the case which capital cost of the plant is low and transport cost is high, making biofuel in multiple small-scaled plants is more economic than single large-scaled plant.

An optimization model OMNIBUS is developed to design an optimal biomass utilization system for rural area. The model calcurate the optimal system configuration to meet economic feasibility considering energy output and CO_2 reduction. The model is applied to Miyakojima city and the optimal system structure is designed in three cases such as (1)basic case, (2)energy output increase case, (3)CO_2 reduction case.

The advantages of coal are the largest reserves among any other fossil fuels, and can be found in many places including some developed countries. Due to the weak energy security of Japan, it is necessary to use coal as an energy source. We have designed the detailed energy model of electricity sector in which we take both energy conversion efficiency and economic aspects into consideration. The Japan model means an energy-economic model focusing on the structure of the energy supply and demand in Japan. Furthermore, the most suitable carbon capture and storage (CCS) system consisting of CO collection, transportation, storages are assumed. This paper examines the introduction of clean coal technologies (CCT's) with CCS into the electricity market in Japan, and explores policy options for the promotion of CCT's combined with CCS. We have analyzed the impacts of carbon tax where each fossil technology, combined with CCS, becomes competitive in possible market. CO mitigation costs for all plants with CCS are detailed and compared. 2 2

Wood pellet has the potential to reduce dependency on fossil fuels, mitigate global warming and stimulate the forest industries. Economics of wood pellet and impact of carbon tax are examined in this study. The target of the study is space heating energy in the residential, commercial and public sectors in Japan. An energy-economic model in which space heating energy is supplied by wood pellet and kerosene is developed. The model contains market share functions that determine how many customers would choose wood pellet depending on the price competition between wood pellet and kerosene.<BR>Model analysis shows the conclusions as follows. Without carbon tax, the pellet price should be less than 35JPY/kg for the market penetration. With 30, 000JPY/tC carbon tax, it becomes 45JPY/kg. Imposing carbon tax leads to an increase in the penetration of pellet except for the case where the pellet price stays at as high level as the current situation. It is also shown that the low cost wood collecting system can drastically increase the utilization of forest biomass such as logging residues and thinned wood in favorable situations. The policy scenario for dissemination of pellet is proposed based on the result of the analysis.

This study analyzes the impact of an electricity grid interconnection between Korea and Japan on their energy systems. Both countries seriously consider energy security as the most important policy issue because of a lack of domestic energy resources. In addition, public concern for the environment is recently rising up in response to the global warming. Electricity grid interconnection has strong potential to cope with such complicated problems cost-effectively. We have developed the interconnection model, which includes the electricity grid interconnection between the electricity sectors of Korea and Japan, considering both technological and economic efficiency. The result of the study reveals the significant cost-effectiveness of the interconnection, in particular, under stringent condition such as nuclear phase-out in Japan and CO emission target in Korea and Japan. In the case that Japan's nuclear power plants will be phased out, the interconnection attains further cost reduction of constructing substitutive thermal power plants. On the other hand, when Korea and Japan set a joint CO emission target, it achieves the emission target more efficiently than they reduce the emission individually. © 2004 Elsevier Ltd. All rights reserved. 2 2

In many countries, the concern with municipal solid waste (MSW) has been growing for the past few decades because of changes in lifestyle as well as constraints in waste disposal site. A remarkable increase in the amount of MSW has generated serious environmental impacts caused by pollutions such as fly ash, sludge, and dioxin etc. Waste management policies should be revised and updated in keeping with progresses in environmentally sound technologies.<BR>The purpose of the study is to design the optimum NISW management system in Japan. We have derived an optimal system configuration among the various alternative and conventional disposal facilities for waste management by applying a NISW system model. which can consider both the mass flow of the wastes and economic aspects of system operation. The advanced MSW management system which has been proposed can reduce the amount of landfill in FY2010 by approximately 40% in comparison with the data in FY 2000. The system increases the recycling rate in FY2010 by 10% compared to FY2000, and meet the budget allocation for NISW management. In conclusion, the installation of alternative facilities in optimal system configuration has a potential for not only the reduction in the cost of landfill but also the improvement of recycling rate.

The study targeted an optimal design of renewable energy system including woody biomass for rural areas. In order to analyze the design of the system, an energy-economic model has been adopted which considers energy conversion technologies, fuel prices and demand for the target area. By analyzing the configuration of the system, some promotion methods of utilization of woody biomass in the target area are shown. The possibility of installing of gasification or direct-fired plant using woody biomass and positive effect of promoting of woody biomass will be discussed.

The purpose of this study is to analyze the economy of biofuel in the transportation sector of Japan. In the study, we considered several kinds of energy crops which are harvested in fallow land. At first, biofuel potential in fallow land was calculated from yield, mineral, and harvesting cost. Then we have analyzed the impact of imported and domestic biofuel together in the transportation sector, as well as apart. In the case which imported and domestic biofuels are consumed together, the following results were obtained: (a) the price of 10% biofuel is almost same as that of conventional fuel, (b) the reduction level of CO_2 is 5.3mmtC/year.

Utilization of forest biomass by small scale gasification technology is the target of the study. Firstly, it is very important to consider the distribution of scattered regional resources in this topic. Secondly, it is expected that gasification technology will reach the economically feasible state by learning effect as the technology breaks into the market. Authors developed BiRReT economic analysis tool, which employs resource distribution and technical characteristics in the economic analysis. Miyagi prefecture is selected as a test region to make an analysis with BiRReT tool, although the tool is applicable to any regions and even with any energy conversion technologies.

The purpose of this study is to promote effective use of biomass. By designing business model, the utilization of biomass could be advanced more than before. Livestock and food biomass are considered in the study. There is more biomass energy resources at both urban and the neighboring area than at local areas, because food biomass has higher heating value than livestock biomass. In order to establish biomass energy business, the following concepts are recommended: (a) using multiple biomass resources, (b) charging a gate fee, (c) reduction in the cost of construction.

This paper presents an application system for animal waste as a biomass resource. A simulation model considering several disposal ways, compost, carbonizing, and methane fermentation, to optimize an application system is designed. Energy and material flows based on each disposal are considered in order to evaluate characteristics of material recycle and energy recovery. Some integrated disposals which combine methane fermentation with compost or carbonizing is also considered in order to reduce disposal residues. In this study, the impact of subsidy for a disposal system has clarified and strategies for sustainable society has discussed.

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This study uses optimization modeling to study efficient ways to integrate renewable energy systems to provide electricity and heat in rural Japan. The model provides minimum cost system configuration and operation taking into account hour-by-hour energy availability and demand. Grid electricity is available to rural areas of Japan, but it is relatively expensive. Local renewable energy generation can be economic while using grid electricity to compensate for the intermittency of the renewable generation. In the model, renewable electricity can be provided by a combination of wind, photovoltaic, and biomass. Heat can be provided by petroleum, LPG, and geothermal heat pumps (GHPs). We find that due to the relatively high cost of grid electricity, there is significant penetration of wind generation. In turn, the penetration of wind creates economic conditions that encourage GHP penetration. The integrated renewable system reduces the annual cost of the entire system by 31%, and reduces the carbon emissions by 50%. © 2003 Elsevier Ltd. All rights reserved.

The study focuses on the design of renewable energy systems introducing biomass resources for a rural area in Japan. In an energy-economic model, woody biomass and animal manure (livestock and poultry manure) have been introduced to supply stable power, combining with wind and PV etc. Intermittency of climate conditions and the changes in demand of electricity are carefully considered to examine cost effec-tive systems for the area. As a result, we have found that gasification of woody biomass can supply electric-ity at a reasonable cost, and the biogasification of animal manure becomes cost effective provided inverse onerous contract of the waste is available. The renewable energy system reduces the carbon emissions by 65%, and reduces the annual cost of the entire system by 15%.

Renewable energy facilities have been installed in many regions, because of their possibility to be an alternative to fossil fuels for mitigating global warming. Besides the profitability of renewable energy businesses, indirect economic effects of installing renewable energy facilities should be clarified. This study examines the possibility that the renewable energy facilities give renewed impetus to regional economic progress. The economic effects are analysed with input-output techniques in a rural area in Japan. As a consequence, both positive and negative effects on the rural economy are derived. In addition, we will focus on the changes in sectors such as construction, business services, banking, etc. as a result of economic activities for renewable systems. The business benefits of renewable energy system are discussed.

The current century - an era of environmental awareness - requires energy resources to satisfy the world's future energy demands. We can use current energy use scenarios to help us to understand how energy systems could change. Such scenarios are not an exercise in prophecy; rather they are designed to challenge our thinking in order to make better decisions today. The conventional modeling approach tends to extrapolate changes in energy consumption from historical trends; however, technology innovation sometimes causes drastic reforms in energy systems in the industrial, commercial, residential and transportation sectors. The economic aspects are another key issue to be considered in order to understand future changes in energy systems. The quantity of the energy supply is set to meet the price of the energy demand of end users. This occurs on the condition that the price of the energy supply equates with the price on the demand side under the market mechanism. This paper reviews the various issues associated with the energy-economic model and its application to national energy policies, renewable energy systems, and the global environment. © 2004 Elsevier Ltd. All rights reserved.

A group was set up to devise a strategy for geothermal development that conforms with global environmental expectations for the 21st century. The group developed the concept of EIMY-Energy In My Yard, which proposes that local energy demands should be met by an optimum combination of local, renewable sources to the maximum degree permitted by technical and economic considerations. Shortfalls and surpluses in local energy production would be accommodated by interfacing with the national grid. The group also discussed the roles that the various types of renewable energy could play within the EIMY framework, according to their nature, ubiquity, and capacity. An integrated renewable energy simulator was used to identify optimum combinations of sources for different situations. Installation and operating costs were assigned at current market rates without weighting for advantages such as low CO emissions. The results demonstrated that integrated renewable energy systems are cost-effective in the medium and long term. Geothermal energy plays a key role as a source of heat in such systems. © 2003 CNR. Published by Elsevier Ltd. All rights reserved. 2

This study is to evaluate the impact of cleaner vehicles on energy systems and CO emissions in the transportation sector in Japan. The transportation sector has the characteristic of spending petroleum. Even when the cost of petroleum rises, conventional vehicles cannot switch fuels to alternative energy right away. Cleaner vehicles, such as fuel cell vehicles, would be one of the alternative technologies in the transportation sector. It is supposed to have excellent performance in fuel efficiency and has strong possibility to reduce CO drastically. This paper uses a multi-period market equilibrium model to explore the impacts of cleaner vehicles on the passenger transportation sector in Japanese energy system out to the year 2040. A Btu tax is tentatively imposed to evaluate the effect of fuel cost on energy consumption in the transportation sector. Financial parameters such as capital cost and operating cost are considered to summarize the profit in taxation case. The result of this study shows that fuel cell vehicles have a great effect on reducing CO emissions especially when Btu taxes are imposed, which in turn has the advantage of encouraging a more diverse set of technologies and fuels. The analysis that petroleum consumption can be reduced using fuel cell vehicles will have effects on perspectives on energy systems in Japan. © 2002 Elsevier Science Ltd. All rights reserved. 2 2 2

Nuclear power is likely to be widely recognized as one of the few options that can help countries meet base load electricity demand with virtually no greenhouse gas emissions. In Japan, the deregulation of Electricity Supply Industry (ESI) is expected to introduce competition into the electricity market and change market structures to lower electricity prices. As investors assume the risk of their investments, incentives to invest in nuclear power become conservative. This research examines the impacts of nuclear phase-out on both energy systems and carbon dioxide emission in Japan. A partial equilibrium model of the Japanese energy sector has been developed to forecast changes in the energy system until the year 2040. This model can account for the changes in energy technology capacities, fuels, and consumption in response to policy initiatives, such as taxes. We find that the nuclear phase-out results in an 8% increase in carbon dioxide emissions by the year 2040. To achieve the same level of carbon dioxide emissions without nuclear power in the future, it will be necessary to charge a 30% higher carbon tax than in a similar scenario with nuclear power. © 2002 Elsevier Science Ltd. All rights reserved.

The high heat flux in MEB far exceeding CHF should be considered a result of violent growing and collapsing behavior of coalescent bubbles in that region, which strongly introduces subcooled liquid to the heated surface. This bubble behavior generates a high pressure in the vicinity of the surface. In this study, a measurement of the pressure fluctuation in the liquid near the surface was performed synchronously with a recording of the bubble motion by use of a void probe set close to the surface. In high liquid subcooling conditions (S-MEB I), the void probe signal in the vicinity of the surface shows regular cyclic behavior synchronous with the pressure waveform. Under a medium subcooling condition (S-MEB II), there appear three different modes in the void signal in sequence. The one looks random and does not synchronize with the pressure waveform. The another is very systematic and similar to the signal in high liquid subcooling. The other shows a constant void fraction of a high value, indicating the surface to be covered with a thick vapor blanket. The time fraction of the second mode increases gradually with increasing the heat flux.

This research examines the impacts of using hybrid vehicles for passenger transportation to reduce carbon emissions from the Japanese energy system. A partial equilibrium model of the Japanese energy sector has been developed to forecast changes in the energy system out to the year 2040. The model can account for the changes in energy technology capacities, fuels, and consumption in response to policy initiatives, such as taxes. We find that although hybrid vehicles are more efficient in reducing carbine dioxide emission than conventional vehicles. Hybrid vehicles have a great impact on emissions with Btu taxes, which have the advantage of encouraging a more diverse set of technologies and fuels.

The development of integrated, coal-gasification combined cycle (IGCC) systems provides cost-effective and environmentally sound options for meeting future coal-utilizing power generation needs in the world. The Japanese government and the Electric Power Indushies in Japan promoted research and development of an IGCC system. We have being working on developing a low-NOx combustion technology used in gas turbine combustors for IGCC. Each gaseous fuel produced from some raw materials contained CO and 1-12 as the main combustible components, and a small amount of CH<inf>4</inf>. Compositions and calorific values of gasified coal fuels varied widely depending on raw materials and gasifier types. Gaseous fuel, produced in various gasifiers, has a calorific value of 4-13MJ/m , which is about one-tenth to one-third that of natural gas. The flame temperatures of fuels increase as the fuel calorific value rises. When the fuel calorific value rises 8MJ/m³ or higher, the flame temperature is higher than that of natural gas, and so NOx production from nitrogen fixation is expected to increase significantly. Also, some gasified coal fuels contain fuel nitrogen, such as ammonia, if the hot/dry type gas cleaning system is employed. These factors affect the combustion characteristics of the gasified coal fuel. In this paper, we clarified the influence of gasified coal fuel properties on NOx and CO emissions through experiments using a small diffusion burner and through numerical analysis based on reaction kinetics. The main results were as follows: (1) NH<inf>3</inf> conversion to NOx increases with increasing CH<inf>4</inf> concentration in gaseous fuel. (2) If gaseous fuel contains CH<inf>4</inf>, there will be some specific equivalence ratio in the primary combustion zone for the minimum NH<inf>3</inf> conversion to NOx in the two-staged combustion. (3) Its specific equivalence ratio in the primary combustion zone increases with decreasing CH<inf>4</inf> concentration in gaseous fuel. (4) If the fuel contains a small percent of CH<inf>4</inf>, there is no influence of the CO/H<inf>2</inf> molar ratio in the fuel on the conversion rate of NH<inf>3</inf> to NOx, while there is an influence in the case where fuel contains no CH<inf>4</inf>. The conversion rate increases with rises in the CO/H<inf>2</inf> molar ratio. (5) As the pressure increases, the conversion rate of NH<inf>3</inf> to NOx slightly decreases and the CO emission declines significantly.

This research examines the impacts of using carbon taxes and Btu taxes to reduce carbon emissions from the Japanese energy system. A partial equilibrium model of the Japanese energy sector has been developed to forecast changes in the energy system out to the year 2040. The model can account for the changes in energy technology capacities, fuels, and consumption in response to policy initiatives, such as taxes. We find that although carbon taxes are somewhat more efficient in some senses than Btu taxes, the difference is not large. Btu taxes have the advantage of encouraging a more diverse set of technologies and fuels, which may be an advantage since energy security is a primary concern to Japan.

Ammonia contained in coal-gasified fuel is converted to nitrogen oxides (NO ) in the combustion process of a gas turbine in integrated coal gasification combined cycle (IGCC) system. Research data on fuel-NO formation are insufficient, and there still remains a wide explored domain. The present research aims at obtaining fundamental knowledge of fuel-NO formation characteristics by applying reaction kinetics to gas turbine conditions. An instantaneous mixing condition was assumed in the cross section of a gas turbine combustor and both gradual mixing condition and instantaneous mixing condition were assumed at secondary air inlet section. The results may be summarized as follows: (1) in the primary combustion zone under fuel rich condition, HCN and other intermediate products are formed as ammonia contained in the fuel decomposes; (2) formation characteristics of fuel-NO are affected by the condition of secondary air mixing; and (3) the conversion ratio from ammonia to NO declines as the pressure inside the combustor rises under the condition of gradual mixing at the secondary air inlet. These results obtained agreed approximately with the experimentation. © 1998 by ASME. x x x x x

The development of "integrated coal gasification combined cycle systems" ensures cost-effective and environmentally-sound options for fulfilling future power generation needs. In our laboratory, we are developing a 150 MW, 1500&deg;C-class gas turbine combustor for IGCC by using an air-blown coal gasifier both to enhance thermal efficiency and to reduce NO<SUB>x</SUB> emission from the plant. This paper descrides the design of the 150MW, 1500&deg;C-class gas turbine combustor, at atmospheric pressure for IGCC based on the stable and low-NO<SUB>x</SUB> combustion technology developed to date. Combustion tests are conducted and the performance of this combustor is evaluated. Test results confirm the excellent performance of the combustor for use in a gas turbine in IGCC and project bright prospects as a high temperature, low NO<SUB>x</SUB> combustion technology of the low calorific fuel.

Developing integrated coal gasification combined-cycle systems ensures cost-effective and environmentally sound options for supplying future power generation needs. The reduction of NO emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in Integrated Coal Gasification Combined Cycle (IGCC) power generation systems. The coal gasified fuel, which is produced in a coal gasifier of an air-blown entrained-flow type has a calorific value as low as 1/10 of natural gas. Furthermore, the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. This study is performed in a 1500PC-class gas turbine combustor firing low-Btu coal-gasified fuel in IGCC systems. An advanced rich-lean combustor of 150-MW class gas turbine was designed to hold stable combustion burning low-Btu gas and to reduce fuel NO emissions from the ammonia in the fuel. The main fuel and the combustion air are supplied into a fuel-rich combustion chamber with strong swirl flow and make fuel-rich flame to decompose ammonia into intermediate reactants such as NHi and HCN. The secondary air is mixed with primary combustion gas dilatorily to suppress the oxidization of ammonia reactants in fuel-lean combustion chamber and to promote a reducing process to nitrogen. By testing under atmospheric pressure conditions, the authors have obtained a very significant result through investigating the effect of combustor exit gas temperature on combustion characteristics. Since we have ascertained the excellent performance of the tested combustor through our extensive investigation, we wish to report on the results. © 1996 by ASME. x x

In integrated coal gasification combined cycle power generation (IGCC) systems, ammonia in the gasified fuel is passed through a hot/dry gas cleanup facility into the gas turbine. The ammonia is converted to nitrogen oxides in the combustion process in the gas turbine. Therefore ammonia removal from coal-gasified fuel would effectively reduce NO<SUB>x</SUB> emissions in IGCC systems. We're defined the optimum NO/NH<SUB>3</SUB> ratio, the optimum concentration of added O<SUB>2</SUB> and the influence of CO and H<SUB>2</SUB> in the coal-gasified fuel on NH<SUB>3</SUB> decomposition and NO reduction by experiments using a tubular flow reactor and numerical analysis based on reaction kinetics. The main results are as follows : (1) The optimum NO/NH<SUB>3</SUB> ratio is about 1 to maximize NH<SUB>3</SUB> decomposition and NO reduction. (2) The NH<SUB>3</SUB> decomposition ratio depends only on H<SUB>2</SUB>, and decreases rapidly with increasing H<SUB>2</SUB> concentration. (3) The NO reduction ratio decreases with increasing H<SUB>2</SUB> concentration. (4) This method is effective for decreasing TFN by up to 60% minimizing the total concentration of remaining NH<SUB>3</SUB> and NO in air-blown coal-gasified fuel.

Developing integrated coal gasification combined cycle systems ensures cost-effective and environmentally sound options for supplying future power generation needs. The reduction of NOx emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in an Integrated Coal Gasification Combined Cycle (IGCC) power generation systems. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of natural gas. Furthermore the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. This study is performed in a 1500°C-class gas turbine combustor firing low-Btu coal-gasified fuel in IGCC systems. An advanced rich-lean combustor of 150-MW class gas turbine was designed to hold stable combustion burning low-Btu gas and to reduce fuel NOx emission that is produced from the ammonia in the fuel. The main fuel and the combustion air is supplied into fuel-rich combustion chamber with strong swirl flow and make fuel-rich flame to decompose ammonia into intermediate reactants such as NHi and HCN. The secondary air is mixed with primary combustion gas dilatorily to suppress the oxidization of ammonia reactants in fuel-lean combustion chamber and to promote a reducing process to nitrogen. By testing it under atmospheric pressure conditions, the authors have obtained a very significant result through investigating the effect of combustor exit gas temperature on combustion characteristics. Since we have ascertained the excellent performance of the tested combustor through our extensive investigation, we wish to report on the results.

ＮＨ３とＮＯの分解反応特性に及ぼす、石炭ガス化燃料中のＣＯとＨ２の影響について、管型気相反応器を用いた実験と反応速度論による数値解析により明らかにした。この結果、以下のことが明らかになった。（１）ＮＨ３の分解反応は、Ｈ２濃度にのみに依存し、ＣＯによる影響は受けない。すなわち、ＮＨ３の分解率はＨ２濃度の増加にともない指数関数的に減少する。また、（２）ＮＯ分解反応についてもＨ２濃度の影響が支配的であり、ＮＯ分解率はＨ２濃度の増加にともない指数関数的に減少する。以上のように、Ｈ２濃度が低いほどＮＨ３とＮＯの分解率は高く、このような観点から言えば、本方式は、流動床ガス化燃料よりもＨ２濃度が高い噴流床ガス化燃料に対してより有効である。

Coal-gasified fuel contains ammonia in a hot gas cleaning system in integrated coal gasification combined cycle (IGCC) power generation systems. Ammonia is converted to nitrogen oxides in the combustion process of a gas turbine. Research data on the NOx formation mechanism in fuel is insufficient, and there still remains a wide unexplored domain. The present research aims at obtaining more fundamental knowledge by means of elementary reaction kinetics. We have obtained a very significant result by comparing the kinetics calculations with combustion experiments. The result is that fuel NO<SUB>x</SUB> formation characteristics is affected considerably by the conditions of secondary-air mixing and the concentration change of methane in fuel.

Developing integrated coal gasification combined cycle systems ensures that Japan will have cost-effective and environmentally sound options for supplying future power generation needs. The reduction of NOx emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in IGCC. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of natural gas. Furthermore the fuel gas contains ammonia when a gas cleaning system is a hottype, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. The study is performed in 1300 °C-class gas turbine combustor firing coal-gasified fuel in IGCC power generation systems. In the previous study° the advanced rich-lean combustor of 150-MW class gas turbine was designed to hold stable combustion burning low-Btu gas fuel and to reduce fuel NOx emission that is produced from the ammonia in the fuel. By testing it under atmospheric pressure conditions, we have studied the effects of fuel parameters on combustor performances and listed the basic data for development applications. In this study, by testing it under pressurized conditions, we have obtained a very significant result through investigating the effect of pressure on combustion characteristics and wish to provide herein a summary of our findings.

Research and development of an integrated coal gasification combined cycle (IGCC) have made steady progress. Low fuel-NOx combustion technology presents great potential for improving IGCC combustors. The authors have developed an advanced rich-lean combustor designed mainly for achieving low-NO<SUB>x</SUB> combustion and flame stability. Under pressurized conditions, we have success-fully reduced the NO<SUB>x</SUB> emissions (to 60ppm corrected at 16 percent O<SUB>2</SUB>) when ammonia concentration was 1000ppm. We have also optimized many design guidelines by clarifying the effects of pressure on combustor performance. This paper describes in detail the characteristics of the advanced rich-lean combustor for use in IGCC.

Research and development of an IGCC (Integrated Coal Gasification Combined Cycle) power generation system is being carried out as one of the advanced coal utilization technology in Japan. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of LNG. Furthermore, the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. The authors have designed and made an 1300°C-class advanced rich-lean combustor mainly designed for achieving low fuel-NOx combustion. By testing it under atmospheric pressure conditions, we have successfully reduced the NOx emissions (to 60 ppm corrected at 16 percent O ) by more than half the level previously achieved when the ammonia concentration was 1000 ppm. Combustion stability was adequate even when the calorific value of the fuel decreased to 2700 kJ/m N. 2 3

This paper describes the development of a 1300&deg;C class gas turbine combustor burning coal-derived low-Btu gaseous fuels. Coal-derived gaseous fuels contain NH<SUB>3</SUB> if a gas cleaning system is hot type and NH<SUB>3</SUB> will be converted to NO<SUB>x</SUB> in the gas turbine combustion process. Combustion tests were conducted by using the newly designed, advanced rich-lean combustor. Combustion stability was excellent for the testing combustor because of a subcombustor, so combustion stability could be obtained even when the calorific value of fuel decreased to about 2 600 KJ/m<SUP>3</SUP>N. As for NO<SUB>x</SUB> emission, NH<SUB>3</SUB> conversion to NO<SUB>x</SUB> was 40% under the full load condition at 1300&deg;C of the combustor exit gas temperature for 1000ppmv of NH<SUB>3</SUB> concentration and 0.7vol% of CH<SUB>4</SUB> in the fuel.

The main combustible gas components of the coal-derived gas fuel are CO and H2. Moreover, a small amount of NH3 and CH4 will be contained. NH3 contained in coal gas fuel will be converted to NOx in the gas turbine combustion process. This paper describes the study of the influence of the coal gas fuel properties such as CH4 on NOx formation from NH3, using experimental study by a laboratory-scale combustor and study of the reaction kinetics. As a result, a small amount of CH4 in coal gas fuel was found to strongly influence NOx formation from NH3 in coal gas fuel.

In the coal gasification combined-cycle power generation system, it is necessary to develop a high-temperature gas turbine combustor using coal-derived gaseous fuels, which has high thermal efficiency and low emission of pollutants. Combustion tests were conducted using a full scale combustor for a 150-MW-class gas turbine under atmospheric pressure. Furthermore, high pressure combustion tests were conducted by using a 20-MW-class gas turbine combustor. Main results are as follows : Thermal NO<SUB>x</SUB> emission was very low in a combustion of coal derived low Btu gaseous fuel, and its emission level was 15 ppm under a full load condition at of the combustor exit gas temperature of 1300&deg;C. The tested combustors were not designed for low fuel NO<SUB>x</SUB> combustion. Therefore NO<SUB>x</SUB> emission resulting from l000 ppmv of ammonia accounted for about 95 % of the total NO<SUB>x</SUB> emissions, The ammonia conversion to NO<SUB>x</SUB> decreased slightly with increasing of combustion pressure.

Coal gaseous fuels contain NH<SUB>3</SUB> which will be converted to NO<SUB>x</SUB> in the gas turbine combustion process, if gas cleaning system is a hot type. Main com-bustible gas components of the coal gaseous fuel are CO and H<SUB>2</SUB>, moreover a small amount of CH4 will be contained. Hydrocarbon such as CH<SUB>4</SUB> has the effect on NO<SUB>x</SUB> formation from fuel nitrogen such as NH<SUB>3</SUB>.<BR>In this study, combustion tests were conducted by using a laboratory scale com-bustor for the study of the influence of the coal gaseous fuel properties on NO<SUB>x</SUB> emis-sion characteristics.<BR>Main results are as follows;<BR>(1) NH<SUB>3</SUB> conversion to NO<SUB>x</SUB> increases with increasing CH<SUB>4</SUB> concentration in coal gaseous low BTU fuel.<BR>(2) If coal gaseous fuel containes CH<SUB>4</SUB>, there will be some specific equivalence ratio in the primary combustion zone for the minimum NH3 conversion to NO<SUB>x</SUB>.<BR>(3) Its specific equivalence ratio in the primary combustion zone increases with de-creasing CH<SUB>4</SUB> concentration in coal gaseous fuel.

石炭ガス化用ガスタービン低公害型燃焼器の開発においては，発熱量の低い石炭ガスをガスタービンの全負荷帯で安定燃焼させる技術や，燃料中のアンモニアから窒素酸化物（ＮＯｘ）への転換率を抑制するための低ＮＯｘ燃焼技術などの確立が重要な課題となっている。本研究では，石炭ガス化用１３００℃級ガスタービン低ＮＯｘ燃焼器として，１５０ＭＷ級実規模「二室保炎強化型燃焼器」を設計・試作し，常圧燃焼実験により燃焼器の性能評価を行った。その結果，副燃焼室を有し，一次燃焼室（燃料過濃域）と二次燃焼室（燃料希薄域）を明確に分離した二室保炎強化型燃焼器では，燃焼過濃域の燃焼安定性がさらに向上し，より効果的なＮＯｘ燃焼を行うことが可能となった。さらに，ＣＯ等の排気特性，壁面温度特性も良好であり，本燃焼器は，石炭ガス化用ガスタービン燃焼器へ十分適用できることがわかった。

A 150-MW, 1300°C (1573 K) class gas turbine combustor firing coal-gasified fuel has been designed. Main purpose of this paper is to estimate CO and NOx emissions, and to discuss the low NOx combustion technology burning such a low-BTU gas. The full-scale, atmospheric-pressure combustion tests were conducted over a wide range of conditions using bypass air. The role of air bypass valve is important for low NOx combustion, and to give stable combustion at lower load conditions. Ammonia conversion to NOx is minimized with a optimum air ratio in primary combustion zone.

In Japan a development program on the coal gasification combined cycle power generation system was started in 1985 by the national government and Japanese electric companies. In this program, the plan is to develop the 1300 °C class gas turbines. However, in the case a hot type fuel gas cleaning system, the coal gas fuel to be supplied to gas turbines will contain ammonia. The authors showed that the rich-lean combustion method is effective to decrease fuel-NOx. In the rich-lean combustion method, the fuel-NOx decreases as the primary zone becomes richer. Flameholding becomes very difficult in the rich primary zone. For this reason this combustor was designed to have a flameholder with a pilot flame. Combustion tests were conducted by using a full scale combustor used in 150 MW gas turbine at the atmospheric pressure condition.

空気制御型の石炭ガス化用ガスタービン燃焼器の大気圧燃焼実験を行い，その燃焼特性およびＮＯｘ排出特性を検討した。その結果，きわめて低い発熱量の燃料でも安定かつ効率的に燃焼することを実証した。また，ＣＯおよびＮｏｘ排出特性は一次空気比の設定に大きく影響されること，さらに，空気バイパス弁は一次空気比の適正化を図ることにより，フュエルＮＯｘの低減および低負荷時のＣＯ排出濃度の抑制に効果的であることなどが明らかになった。

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to developed a high temperature gas turbine combustor using a low-BTU gas (LBG) which has high thermal efficiency and low emissions. In Japan a development program of the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, 1300°C class gas turbines will be developed. If the fuel gas cleaning system is a hot type, the coal gaseous fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel-NOx combustion technology will be one of the most important research subjects. This paper describes low fuel-NOx combustion technology for 1300°C class gas turbine combustors using coal gaseous low-BTU fuel as well as combustion characteristics and carbon monoxide emission characteristics.

本報告は，石炭ガス化用ガスタービン燃焼器内における燃焼反応系を，素反応モデルを用いて解析し，おもにサーマルＮＯｘ，ＣＯ排出特性について当所で行なった燃焼試験結果と比較，検討を行なったものである。解析結果は実験値と良く一致し，本解析法はガスタービン燃焼器の燃焼特性を予測する上で優れた手法であることが明らかになった。

本報告は，石炭ガス化燃料の燃焼安定性向上に有効と考えられる部分予混合燃焼法について，基礎燃焼特性およびガスタービン燃焼器への適用性を評価したものである。その結果，部分予混合燃焼法は燃焼安定性を向上するだけでなく，二段燃焼法と組み合わせることによって，ガスタービン燃焼器の一層の低ＮＯｘ化が可能であることが明らかになった。

本研究は，我国で使用されている発電用石炭のうち，主要な２８炭種の燃料試験を実施し，石炭性状からＮＯｘ排出濃度および灰中未燃分濃度を予測する手法について検討したものである。その結果，以下のことが明らかになった。（１）燃料中のＮ分からＮＯｘへの転換率は，石炭性状のうち燃料比とＮ分含有率の比の一次式で精度良く予測できる。（２）灰中未燃分濃度は，従来提案してきた予測式がさらに多くの炭種に対しても適用できる。以上より，微粉炭燃焼におけるＮＯｘおよび灰中未燃分排出濃度を，幅広い石炭性状を有する多炭種に対して精度良く予測する手法を明らかにした。

石油価格は昨年末より低く安定しているが，内外のエネルギー情勢は今後とも流動的と予想され，その変化に適切かつ弾力的に対応していくには，将来の火力発電技術に対する要請，役割に応じた火力発電の高度化を図っていくことが重要である。本調査では，火力発電技術の高度化目的とする燃焼診断システムの開発状況と，レーザー光等の光技術を応用した燃焼計測技術について調査し，評価，検討を行った。その結果，燃焼診断システムの高精度化，高性能化を図るには，システムに入力する情報量の増加とデータの高精度化が不可欠であり，また，それらのデータを解析する精度の高い手法の確立が重要であることが明らかになった。

石炭の燃焼状況は、バーナの特性に影響される。このため、各種石炭の発電用炭としての適性を評価するためには、異なるバーナを用いて、より一般的に検討する必要がある。本研究は、NRバーナを用いて、NOxと灰中未燃分の排出特性におよぼす石炭性状の影響を明らかにし、以下のことが明らかになった。<br /> 1．燃料中のN分含有率(FuelN)からN()xへの転換率は、FuelN,燃*壮ヒの二つの因子から予測できる。<br /> 2．灰中未燃分は,燃料比から予測できる。 <br /> さらに,この手法は、従来のSGRバーナと同様であり、評価因子の一般性か確められた。