Currently, most of the chemicals are produced from petroleum-derived raw materials, emitting a large amount of CO2. The Ministry of Economy, Trade and Industry thus presented a carbon recycling technology roadmap in June 2019 with the aim of reducing CO2 emissions. On the other hand, the recycling of organic carbon fixed to biomass and used plastics is also very attractive when considered as a self-sustaining carbon recycling process that does not largely depend on external energy. In the presentation, I would like to talk about and discuss the possibility of carbon recycling type chemical production using organic matter as a raw material, especially fermentation technology.
The purpose of this study is to clarify the supply capacity and supply area for cross-border supply of woody biomass resources to the surrounding demand areas, while considering the productivity of the harvesting systems such as whole-tree, tree-length, and cut-to-length logging systems. In addition, in order to guarantee the sustainability of fuelwood production, the harvesting schedules of woody biomass resources are optimized using a linear programming (LP) model. Moreover, heat demand is estimated for both the commercial and residential sectors of municipalities. As a result of integrating the above analysis, it is found that the availability of sustainable woody biomass in the Oku-Aizu region can satisfy the heat demand of nine municipalities.
In Tsuruoka City, Yamagata Prefecture, Japan, Swidden is traditionally carried out in the forest land after clear-cutting. It is regarded as one of the efforts to promote reforestation. We evaluated the effect of reducing WB production cost itself and biomass power generation cost, and the impact of swidden on the revitalization of this area. It was clarified that the improvement of work efficiency and the sales profit of swidden can reduce the cost by about 7% in terms of WB production and about 5％ in terms of biomass power generation. It was suggested that swidden has a certain effect on both increasing the use of WB and achieving economic independence in the forestry.
In this work, a small-scale biomass-based combined heat and power (CHP) system with energy/exergy recuperation for highly efficient power generation was investigated by Aspen PlusTM commercial software. The CHP system is mainly composed of a gasifier, a solid oxide fuel cell, a gas turbine and some auxiliary equipment. To obtain the best performance, the energy and exergy analyses of total system are carried out in details. The results demonstrate that 263.65 kW of electrical power could be generated with the total energy and exergy efficiencies of 37.9% and 43.2% in the optimum operation condition, respectively. Corresponding to the CHP system, a separated-type biomass gasifier combining the energy/exergy recuperation is proposed. The spatial subdivisions of the processes in biomass gasification such as pyrolysis, oxidation and reduction are adopted to realize the optimization of each conversion step and improve the whole system performance.
We surveyed and analyzed the current status of household energy consumption and use of firewood and other wood biomass in the town of Mishima in Fukushima Prefecture for the purpose of building a supply chain model for forest resource use in mountainous regions.
This paper reports on characteristics of clinker in a gasification plant using Japanese cedar pellets as a fuel in Japan in relation with the analysis of clinkers generated in the gasifier. The upshot is that the cause of generating clinkers in a gasification plant using cedar pellets is not the formation of glassy material of aluminum-silicate but the formation of K2CO3-Liquid phase in this condition of the reactor temperature of less than 1000 degrees Celsius. The countermeasure for suppression of clinkering is to add aluminum compounds to cedar sawdust by which the formation of K2CO3-Liquid phase, the main cause of clinkering, is avoided by the formation of KAlO2 phase. In practice, Oobae-Kuroshio Power Plant has achieved a high utilization factor by applying aluminum compounds as additives.
This study aims at a comprehensive investigation on properties of ash from Japanese cedar, Japanese cypress and Norway spruce in regard to places of origin and procedures and conditions of measurement focusing on ash melting characteristics suitable for gasifier fuels. It has been found that the potassium content of Japanese cedar is higher than that of Norway spruce pellets and have variation by place of origin and that, ash melting behavior of biomass (e.g. cedar) of high potassium content has significantly different characteristics in air oxidizing atmosphere and in CO2/CO and CO2 atmosphere. Moreover, samples in CO2/CO and CO2 atmosphere showed bubbling at about 750 - 800 degrees. This is why measurement conditions for ash melting characteristics suitable for gasifier fuels should be in CO2/CO and CO2 atmosphere and ash melting behavior should be judged based on its bubbling behavior as well as on the change of sample cross-sectional area (vertical) with temperature.
In recent years, various small-scale gasifiers less than 2MWe have been introduced in Japan under a feed-in tariff (FIT). Among them some gasifiers have been designed in Europe for pellets of properties satisfying the EN Plus A1 standard. However, even when the above requirement of EN Plus A1 is satisfied, there have been cases of severe clinker troubles within one week or shorter operation period. We found that it is because of the melting property of the pellets which is related to the chemical composition of minerals contained in the wood.
Woody biomass is attracting attention as an alternative energy to fossil fuels. The use of woody biomass is expected to expand in the future. In order to use biomass efficiently as a fuel, it is necessary to clarify its combustion characteristics. Therefore, in this study, in order to clarify the combustion characteristics of biomass, a biomass combustion experiment was conducted using a bubble fluidized bed. Palm Kernel Shell (PKS) was used as an experimental sample. The effect of temperature on the combustion behaviors of biomass was experimentally considered.
Operational problems in biomass-fired boilers include ash deposition to heat transfer tubes and corrosion of heat transfer tubes. Therefore, in this study, we focused on potassium compounds in biomass and conducted an ash deposition experiment using an electrically heated drop tube furnace. In the experiment, potassium-containing mineral (K-feldspar) was used as simulated ash. The amount of ash deposition in various atmospheres was measured. The cross section of samples was observed and analyzed by SEM-EDX, and the atmosphere dependence of the ash deposition characteristics was experimentally considered.
This study reports the effects of electron injection into the air on the syngas and tar generations during the oxidative pyrolysis of cellulose using a laboratory-scale cylindrical fixed-bed reactor. During the experiments, the feedstock was heated by an electric heater to 600°C with or without electron injection into air. The analysis results of syngas and tar samples showed that there was an incrase in the syngas generation rate and a decrease in the tar generation as well as a change in the tar composition by electron injection at 600°C.
Biomass sometimes ignites due to composting and chemical oxidation. If this phenomenon (spontaneous ignition) could be controlled, it would be possible to produce biochar at a lower cost without the need for an external heat resource. We investigated the effect of differences in the components on self-heating using bark chips and sawdust. Comparing the ash content of bark chips and sawdust, the ash content of bark chips was about 2% higher than that of sawdust. When the self-heating experiments conducted with bark chips and sawdust under the same conditions, the bark chips were rose to the carbonization temperature. Since the inorganic substances contained in the bark chips may affect the self-heating, the inorganic substances were removed by washing with water. Self-heating was suppressed by removing the inorganic substances. Therefore, it’s considered that the inorganic substances in the biomass affect the self-heating.
For the efficient utilization of waste biomass in Saga city, the economic and environmental impact of the process for producing biomass derived-succinic acid (bio-SA) were studied quantitatively. The bio-SA yield and input energy were calculated to estimate the annualized cost and CO2 emission for plant operation through process simulation. The process consisted of five unit operations including grinding, pretreatment/saccharification, H2SO4 removal, fermentation, and purification. Waste biomass such as sawmill scrap, wood chips, sawdust, and construction generated wood were selected as feedstock, and the capacity was 24 t-dry/d. Process simulation indicated that the bio-SA was obtained at 7.2t/d. The utilization of waste biomass in Saga city can not only produce bio-SA but can also reduce the annualized cost to 313 M¥/y and lead to no CO2 emissions derived from utilities.
This study aims to analyze a rice husk energy utilization system considering monthly generation. The rice husk generates from country elevators on every month without June and July, and generates from other farmers on September and October. I focused on the rice husk from country elevators that stably generated. The system boundary was from rice husk generation in country elevators to the energy conversion that co-firing in coal power plant was assumed. Three cases were considered; first was that rice husk was not processed and transported, second was that rice husk was grinded and transported, and third was that that rice husk was compressed and transported. As a result, the lowest energy consumption and cost was obtained in the case that not processed rice husk was transported by 20t truck. Furthermore, if 20t truck could not be used, grinded rice husk should be transported by 4t truck.
The study summarizes international debate on carbon debt of bioenergy. The carbon neutrality concept that CO2 emitted from energy conversion of biomass fuel can be considered as zero is increasingly criticized for its longer payback time. On the other hand, there are quite a few counter arguments; tree harvesting for fuel production is not common in practice, the debt doesn’t occur since the carbon stock is increasing when it is measured in landscape level. The review indicates that results and implications of carbon debt studies can be different according to its time and scale assumption. Therefore, it can be thought that carbon debt should be used as one of the indicators to optimize biomass utilization strategy for decarbonization, which should be considered in the Japanese energy policy.
Pellet stoves use wood pellet as fuel. The wood pellet is made from sawdust which occurs when making wooden products. So, wood pellet is carbon neutral and effective to solve the environmental problem such as depletion of fossil fuel and global warming. Therefore, it is a good idea to use pellet stove instead of devices which use fossil fuels. However, pellet stoves have some problems. For example, the exhaust gas from pellet stove contains much soot, which is harmful to human health. Thus, it is difficult to use in residential area. Therefore, it is important to remove soot from exhaust gas from pellet stove. In this research, we sprayed water to the exhaust gas from a pellet stove which contains soot.
Nowadays, biomass is becoming an alternative energy source besides conventional fossil fuel. In this study, hybrid process consisting biomass pyrolysis, steam tar reforming, and biochar direct chemical looping was designed to produce power and hydrogen from biomass simultaneously. Biomass is pyrolyzed to produce tar and biochar at first, and then the produced tar is reformed into hydrogen rich syngas while the biochar is converted to high purity hydrogen and power simultaneously. Pressure swing adsorption (PSA) is used to separate the hydrogen from other gases in the syngas. The tail gas from PSA separation is burnt to provide heat required by steam tar reforming process. Heat circulation of hot gas is used as heat carrier for biomass pyrolysis process so the total system is operated auto-thermally. This small-scale system can produce about 100 kW of power and 11.8 kg/hr of hydrogen with purity of 99.5% by converting 172 kg/hr of woody biomass.
Co-gasification of various biomass feedstocks takes advantage of intrinsic catalytic species to improve gasification rate. In this work, banana peels (BP) were co-gasified with other biomass such as Japanese cedarwood (CW) and rice husk (RH) to produce H2-rich fuel gas. The influences of reaction temperature and the mixing ratio on the steam co-gasification rate were studied. Since BP contains a high content of potassium (K), which could enhance the gasification of CW and RH, the gasification of CW was greatly enhanced in the presence of BP. Otherwise, the co-gasification of RH and BP showed a negative effect due to the high content of silicon (Si) in RH which tended to retard the activity of alkali compounds by the forming of alkali silicates.
Cellulose in hydrocarbon solvent was first converted into levoglucosan, HMF, furfural, and levulinic acid. These polar compounds were adsorbed on the surface of cellulose because it is immiscible with hydrocarbon solvent, and then interfered with cellulose decomposition. In contrast, in hydrocarbon solvent with palladium on actived carbon (Pd/C), the polar compounds were hydrogenated, and cellulose decomposition was promoted.
Torrefied Japanese cedar (Cryptomeria japonica) wood pellet and its untreated pellet were emplyed for heating test at aglicultrural greenhouse located in Kochi Pref. using commercial pellet heating appliance. In the start-up period on combustion, torrefied pellet showed faster ignition and more rapid rising of temperature compared to normal pellet. Thermal efficiency was slightly incresed for torrefied pellet when air ratio was given appropriately. The temperature inside a greenhouse was fully controlled for the torrefied pellet, as well as for the normal pellet. Total fuel consumption was decresed for torrefied pellet, while ash content after combustion was higher compaed to normal pellet. These results showed torrefied fuel could be applied as renewable energy source for agrilucultural industry in rural area.
Catalytic upgrading of biomass pyrolysis vapors over Cu/H-ZSM-5 was performed. The chemical composition of bio-oil and specific aromatic yield over Cu/H-ZSM-5 with different the Cu-loading amounts were investigated in a fixed-bed reactor at reaction temperature of 500ºC for 5 min. It is found that the H-ZSM-5 crystal structure and the zeolite acid sites were maintained after the loading of Cu. The relative amounts of aromatic hydrocarbons achieved a maximum 73.2% over 0.5wt.% Cu/H-ZSM-5 from 55.0% over the parent H-ZSM-5. The optimum Cu loaded catalyst (0.5wt.%) exhibited the best catalytic efficiency with the increased aromatic hydrocarbon production and a maximum yield of 98.0mg/g of bio-oil was achieved, which was much higher than that in the case using the parent H-ZSM-5.
To make paper mulch alternative to plastic from non-woody biomass, the pulping by alkaline-peroxide treatment using a biomass crop, Miscanthus×giganteus was investigated and basic characteristics of the sheet prepared from this pulp were analyzed in this study.
We focused on microalgae in term of high energy potential. Hydrothermal carbonization is suitable for recovering energy as hydrochar from microalgae which have high water content. This study investigated the relationship between conditions variation and the fuel characteristic of hydrochar. First, we created the models which visualized the effects of conditions variation using response surface methodology (RSM). From the model of mass yield and solid phase ash content, the time had the greatest effect. Therefore, we conducted the time course experiment with reaction temperature of 200℃. As a result, it was found inorganic components such as magnesium and calcium were reprecipitated. This is thought to be due to the improvement in surface function of hydrochar.
A winterization is a method for improving the cold flow properties of biodiesel fuel. In this method, saturated fatty acid methyl ester (FAME) having a high melting point is preferentially concentrated on the solid side at low temperature.However, this method does not allow easy phase separation because of liquid inclusion. In this study, Span40 was added to a FAME mixture to improve phase separation. When a small amount of water was also added to the FAME mixture, saturated FAME rich spherical particles having water droplets as nuclei were obtained in a part of the solid. These particles could be easily separated by sieving. The effect of water addition on particle size distribution and particle yield were investigated. As the amount of water added increased, the particle size reduced, the yield of spherical particles increased, and the uniformity of the particle size increased.
Biodiesel fuel (BDF), which is mainly composed of fatty acid methyl ester (FAME), is a biomass fuel as an alternative to light oil. It can be produced by esterifying vegetable oils, animal fats and oils, and waste cooking oils with methanol. BDF has a problem with cold flow properties due to the high melting point of saturated FAME in its constituents. Separation of saturated FAME, which is a high melting point component, can improve low temperature flow characteristics and increase the use as a liquid fuel dramatically. A sweating operation is proposed as one of the separation methods; after solidifying all of the BDF samples, the melted liquid is separated from residue solid by melting operation at a constant temperature. However, the phase separation performance of FAME mixing is low. In this study, the additive was added to the pseudo BDF to promote the phase separation during the sweating operation. When the additive concentration was 2.0wt%, the separation efficiency increased 1.50 times and the liquid recovery rate also increased as compared with the nonadditive case.
In order to commercialize algae biomass fuel, improvement of algae biomass production and equalization of production throughout the year are major issues. However, in Japan, a decline in biomass production in winter is inevitable. Therefore, we considered leveling the production volume by heating and cooling the culture pond with waste heat. In last year's report, we confirmed the effect of heating and cooling of the culture pond on algae production and showed the effect of waste heat utilization. In this report, as the next step, we report the results of a simulated experiment on how to recover, transport, and use waste heat.
Algae are currently expected to be a promising destination for CO2. The purpose of this research is to confirm the effect of algae culture using actual exhaust gas from thermal power plants and to understand the CO2 utilization rate. As a result, it was clarified that culturing with actual exhaust gas has a great effect of increasing the utilization rate of CO2 in exhaust gas and improving the culture amount of algae.
One of major costs in microalgae cultivation is nitrogen fertilizer. In this study, the growth of a hydrocarbon producing green microalga, Botryococcus braunii (B.braunii), was investigated using ammonium carbonate, ammonium hydrocarbonate and urea as nitrogen source. The growth of B.braunii in urea medium was almost the same as that in Chu 13 medium (nitrate as nitrogen source). However, B. braunii didn’t grow in ammonium carbonate medium or ammonium hydrocarbonate medium. The pH of the mediums were higher than 7.5 and free anmonia inhibits the growth of B. braunii.
The renewable hydrogen is promising in terms of the contribution to global warming protection. As one candidate, sewage sludge is available, but the usage range would be narrow due to the low calorific value. In this study, we proposed the performance advances of H2 production through the gasification process. The heat shortage is compensated by the additional charcoal. In addition, the CO2 gas exhausted from the H2 purification system of 2step PSA and the CO2 obtained by the partial combustion are available as a gasifying agent, and the performance gain can be achieved by both agents. Consequently, the advantage is approximately 30% of production efficiency, that is, 2 to 3 points can be gained in comparison to the sewage sludge only.
The objective of this study was to investigate the odor control of anaerobically digested liquid and evaluate it with odor index. Dairy manure was separated into solid and liquid fraction by screw press and the liquid fraction was used for mesophilic anaerobic digestion. First, fermentation management was examined to control the odor of abaerobically digested liquid. Low volatile solids concentration reduced the odor index by 9 points from raw materials; however,longer hydraulic retention time did not lead to the clear decrease of the odor index. Next, the post-processing by the storage or the aeration was examined. The storage under 15 or 25°C for 1–2 months reduced the odor index by about 5 points. The aeration released hydrogen sulfide from the anaerobically digested liquid; however, excessive aeration led to release annmonia after hydrogen sulfide.
This study estimated the supply potential and availability of unused materials of cedar, cypress, pine, and larch for woody biomass power generation in Aomori, Iwate, Miyagi, Akita, and Yamagata prefectures. As a result, supply potentials of used and unused materials were estimated at 11,388,960m3/year and 2,277,792m3/year. Then, those availabilities were estimated at 1,630,207m3/year and 326,041m3/year. Therefore, the rate of availabilities to supply potentials was 14.3%. The demand was estimated at 951,740m3/year from 100,000m3/year with the generation capacity of 5MW. The rate of unused material availability to the demand was 34.3%. The rates as a unit of subcompartments and aggregated forests with thinning subsidy were increased to 91.4% and 190.3%, respectively. Thus, the estimated availability with thinning subsidy met the demand sufficiently in this region.
Fruit pruning can be expected to be used as a fuel of small-scale and high-efficiency gasification to produce heat and power. In the previous study, kinetic analyses on CO2/O2 gasification of fruit pruning have been performed. In this study, the characteristics of Fruit pruning chars in CO2/O2 gasification were evaluated by comparing that for reference biomass chars (park pruning chars and timber waste chars). Furthermore, a new kinetic model was proposed that was applicable for the pruning gasification in CO2/O2 atmosphere. As a result, the reactivity of several chars was different upon K content due to generating form. The n-th order extended modified random pore model (nMRPM) predicted the instantaneous reactivity better than MRPM with higher R2 value (coefficient of determination) than MRPM. Moreover, nMRPM showed better coefficient of determination with higher temperatures and higher O2 concentration.
Woody biomass fuel demand for domestic power and heat production has been increasing. For a stable bioresource supply, herbaceous perennial energy-crop such as Erianthus arundinaceus (Erianthus) is a promising option. Erianthus (JES1) grew about 14 t/ha in Nasu-shiobara, Japan and stand-dead, leading to small drying cost. However, clinker formed by ash or char melting during gasification could decrease in operating time, leading to a worsening of profitability. In this study, the fusion characteristics of Erianthus ash and char were investigated. First, the TG and DTA curves of Erinathus Ash were obtained using TG-DTA, resulting that the TG curve decreased by approximately 10% in 800–1000°C and decreased by approximately 10% in 1100–1300°C. The DTA curve showed negative peaks at about 700, 900, and 1200°C. In the high temperature melting test, softening of Erianthus ash was observed between 700 and 800°C, and the melting was observed between 900 and 1000°C. In addition, thermodynamic equilibrium calculations revealed that the amount of slag liquid produced accounted for 70% at 700°C; that a phase transition of chloride occurred at 750–800°C; and that the ash volatilized at 1000–1300°C. In the XRD pattern, a KCl, K2SO4, SiO2, K(AlSiO4) peak was observed.
In this study, ash adhesion formed by bamboo particles with adding silica powder on the metal surface under high temperature atmospheric condition was investigated. Not only electric furnace but also the flat flame combustion was used as the high temperature atmospheric conditions. Titanium plate was used as the metal surface during electric furnace oxidization. It was found that the adhesion amount of the ash during electric furnace oxidization at 600 °C had a minimum value at a certain mass of silica powder and then increased with the silica powder. At 800 °C, the adhesion amount of the ash increased with the silica powder. Inconel mesh was used as the metal surface during flat flame combustion. The adhesion amount of the ash on the Inconel mesh increased with the amount of silica powder. Therefore, it was found that the adhesion behavior of ash formed by bamboo particles during flat flame combustion could be different from that during the electric furnace oxidization.
For reduction of the greenhouse gas emission to mitigate climate change, promotion of the renewable energy is considered to be essential. The spent mushroom substrate (SMS) is the waste biomass that is generated in a mushroom cultivation process. During the use of the SMS as a fuel of small-scale gasification to produce heat and power, clinker problems often occur in the inside of the gasifier and around heat exchanger. Therefore, in our previous study, SMS was added to the Japanese cedar to obtain the mixed fuel with a high softening and melting points than a cedar. However, the effect of SMS on reducing clinker have been still unclear. In this study, thermogravimetry/differential thermal analysis (TG-DTA), high temperature heating test, and solid solution thermodynamic equilibration calculation were performed to clarify the products contributing to clinker formation. From the results, the fusion temperature predicted by the FactSage was consistent with that for high temperature fusion examination. Ca2SiO4 played a key role of fusion temperature of SMS.
Wood pellets have been attracting attention in heating and gasification of power generation. Therefore, a higher quality of pellet moldability is required. However, the behavior of wood components in pellet materials during production is unknown, especially under molding conditions. In this study, we focused on hemicellulose structure, which is the most sensitive to heat and moisture among the wood components. We performed a hot pressure test on airdried wood flour and investigated the molecular behavior of hemicellulose in the wood cell wall. However, no clear change in the molecular weight of hemicellulose in the wood cell wall due to heat compression of airdried wood was observed in this experiment.
BDF solidifies at a higher temperature than light oil when placed in a low temperature environment. The BDF was electrostatically purified, and two types of additives, a low-temperature fluidity improver and a cetane number improver, were added. Exhaust gas and power generation were measured by putting samples classified according to the presence or absence of two types of additives and electrostatic purification and the storage environment into a small generator and operating it. We also observed the state of BDF placed under low temperature conditions.
To test the slurryability of the sludge after hydrothermal pretreated for recovering energy with sludge incineration and sludge transportation of sewage sludge, hydrothermal pretreatments and in turn viscosity measurement/zeta potential measurement of the slurry obtained after drying the pretreated sludge were performed at laboratory-scale. The hydrothermal temperature fell within the range of 393 K-493 K and fixed the pretreatment time to 30 min . For the sludge after hydrothermal pretreatment within ranges of 473 K-513 K the pH value of the sludge was adjusted to 11.0 by adding NaOH. The results showed that the absolute value of zeta potential of the sewage sludge was improved with increasing pretreatment temperature above 473 K. Under hydrothermal condition at 513 K, The addition of NaOH gave a better performance on the fluidity of the pretreated sludge compared to pure hydrothermal pretreatment
Recently, conventional plastics are disadvantage because the dumping of plastics into the natural environment has become a source of extensive environmental pollution. Hence, plastics that are derived from renewable sources as biomass instead of petrochemicals are receiving interest. Polyhydroxybutyrates (PHB) is a biodegradable polymer that belongs to polyhydroxyalkanoates (PHAs) which is produced by numerous microorganisms under stress conditions In this paper, we introduce the study of PHB production using a new bacteria isolated from Ishigaki island compost.
For economic and environmentally benigh production of acromatic hydrocarbons as the starting material of various chemicals, catalytic hydrotreatmenmt of o-cresol as a model compound of lignin was performed in the presence of aqueous solution of glucose at the temperature of 453-513 K. Since suppoeted Pt catalysts allowed o-cresol to be converted into methylcyclohexane appreciably, it was evident that the hydrogen required for the o-cresol conversion was produced in-situ by aqueous phase reforming of glucose. The conversion ratio reached maximum value at 473 K. The catalytic activity was enhanced markedly by selecting active carbon or H-Y zeolite as the supporting material.
Hydrothermal gelation of cellulose nanofiber dispersion was conducted. In general, the gelation of cellulose nanofibers through conventional crosslinking or reprecipitation requires the use of additives. The preparation of a self-sustaining hydrogel from cellulose was achieved without any additives in hydrothermal gelation. Such additive-free hydrogels that can be shaped into diverse forms are promising for medical applications.
To develop a novel component separation process of woody biomass, pre-hydrolysis of wood chips soaked in 2,4-dimethyl phenol, alkaline peroxide treatment, and mechanical nano fibrillation of the pulp obtained by these treatments were investigated.
After the great earthquake and nuclear accident of 2011, the Japanese government and Fukushima prefecture promote installation and utilization of renewable energy in the new context such as local renovation. For utilization of woody biomass, forest in Fukushima has the contamination problem and the special attention should be paid to handle the contaminated materials. In the paper, the former part described the situation and trends of utilization of woody biomass in Fukushima, and the later part discuss on the problems of installation of small-woody biomass energy system in the view point of circular economy in both rural area and recovery area.