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Hydrothermal carbonization (HTC) is a promising process for the upgrading of wet biomass residues. Models of HTC processes, in particular at continuous pilot-scale, are needed to move HTC from lab-scale to industrial scale. This study presents a process model for mild HTC, dewatering and conversion to intermediate energy carriers (bio-pellets and biogas for power and/or heat production) of three wet biomass residue streams: paper sludge, olive pomace and orange peels, based on lab- and pilot-scale experiments. In addition, the process energy efficiency and feedstock utilization of the HTC process is calculated and compared with conventional treatment options for the chosen residues, i.e., direct anaerobic digestion (olive pomace, orange peels) or combustion after conventional dewatering (paper sludge). The process model indicates that the HTC pilot-scale process is much more efficient in terms of feedstock utilization to produce heat and/or power than the reference scenarios. The process energy efficiency of the HTC process (pilot-scale) was calculated to be 26 %, 63 % and 40 % for paper sludge, olive pomace and orange peel feedstocks, respectively. For all feedstocks, both the solid and liquid-generated products are equally important for improving the overall process energy efficiency. This study demonstrates the potential benefits of HTC processes for upgrading wet biomass waste streams based on continuous pilot-scale data. • Hydrothermal carbonization successfully upgraded wet biomass residues for energy. • Hydrothermal carbonization was more efficient for heat/power than reference cases. • Solid and liquid products are both important to improve process energy efficiency. [ABSTRACT FROM AUTHOR]

Chemi-mechanical pulping (CMP) is a typical high-yield pulping technology to produce various papers and paperboards due to its high yield and high fiber properties. However, it is challenging to further improve its energy efficiency without the scarification of fiber quality. To attack this challenge, herein we study the effects of different hemicellulose pre-extraction on the viscoelasticity of wood cell wall, the energy efficiency, and product properties in chemi-mechanical pulping (CMP) process. Hardwood was first pretreated by NaOH to hydrolyze the benzyl ester bonds that link lignin with hemicellulose, aiming to partially remove hemicellulose and weaken the inter-fiber connections. Then, the hemicellulose-extracted wood underwent refining. The chemical distributions of wood, fiber morphologies, fiber surface fibrillation, energy consumption, and paper properties were extensively studied. The results showed that a 40.8% removal of hemicellulose corresponded to a 90.3% reduction in wood storage modulus (E') and a 68.3% decrease in specific refining energy consumption. Moreover, the weaker connections between microfibrils in the secondary layer, caused by hemicellulose extraction, promoted fiber surface fibrillation during pulp refining. The study elucidates the nonnegligible role of hemicellulose as the linking "bridge" between lignin and cellulose. It also provides a new mechanism in addition to the current classic pulping mechanism including lignin chemical/thermal softening and cellulose swelling in both CMP and chemi-thermomechanical pulp (CTMP). This study offers a feasible and efficient approach to extract hemicellulose from hardwood to reduce the refining energy without scarification of fiber quality, therefore, it holds promise for advanced and greener biorefineries. [Display omitted] • The mechanism of chemical-mechanical pulping about hemicellulose was supplemented. • Removal 40.8% of hemicellulose reduced wet woods' storage modulus by 90.3%. • LC ester bonds hydrolysis weakens connection inter-fibers and inter-microfibrils. • Wood de-hemicellulose optimized fiber separation and fibrillation in refining. [ABSTRACT FROM AUTHOR]

Densification is the most effective forming technology, the production of which, pellets are the most intensive energy content of biomass solid fuels. Increasing the overall utilization efficiency of bioenergy, extending available types of wastes and residues for pelleting, and improving the pellet quality comprehensively are necessary. This paper reviewed feedstocks used for pelleting, binding mechanism of biomass pellets, and evaluation systems of pellet qualities. To extend the supply amounts and improve the qualities of raw biomass, various feedstocks and formulation recipes were classified based on their regions, sources, and species. And applicable objects and conditions of several different pretreatment technologies for feedstocks were compared. Physical properties and biochemical analyses are also concluded to evaluate the flowability, compactibility, and potential characteristics as solid fuel. For a better understanding of energy consumption and conversion during the densification process, pelleting devices and binding mechanism are elaborated. Associations and differences between single pelleting press in lab-scale and industrial pelleting in pilot-scale are also discussed. Suggestions are proposed for the optimization design of pelleting devices and processes for different feedstock densification. Lastly, relationships between operating parameter factors of pelleting process and pellet quality are presented. This review could provide theoretical analyses for powder compression, new insights for waste to energy, and guidance for achieving global peak carbon and environmental strategic objectives. [Display omitted] • Biomass feedstocks and recipes used for pelleting are reviewed. • Pelleting process is explained from theoretical and experimental aspects. • Durability and water sorption of biomass pellets are discussed. • Suggestions are given for optimizing pelleting process and mechanical device design. • New methods and concepts in industrial pelleting are presented. [ABSTRACT FROM AUTHOR]

The interactions among chlorine (Cl), sulfur (S), and alkaline and alkaline-earth metals (AAEMs) are the critical factors that affect the formation, transformation, and deposition of ash during biomass and coal gasification and combustion. These issues cause slagging, agglomeration, corrosion, and other problems related to the safety performance of gasifiers and boilers. A better understanding of the determination methods, modes of occurrence, migration routes, and control technologies of Cl and S is the basis for clean and efficient utilization of biomass and coal. The paper summarizes the research work in this field, namely: (1) The modes of Cl and S occurrence in biomass and coal are introduced, mainly in different forms of inorganic and organic Cl/S compounds; (2) The principles, merits and demerits of quantitative determination methods for Cl and S are sorted out and compared; (3) The migration routes of Cl and S, mainly related to their modes of occurrence, reaction evolution, temperature, and atmosphere; and (4) The interactions among Cl, S, and AAEMs and its induced issues, especially the challenging problems related to ash, including alkali-induced slagging, silicate melt-induced slagging (ash fusion), agglomeration, and corrosion. Finally, ecological and technological significance of the Cl and S release is discussed. This knowledge is of great significance to effectively control the emission of Cl and S pollutants, stable operation of gasifiers and boilers, cleaner and more efficient utilization of coal, as well as to diminish the consumption of fossil energy and heighten the availability of renewable energy in such thermochemical conversion processes. • Migration routes of chlorine and sulfur are elucidated. • Interactions among chlorine, sulfur, and AAEMs are summarized. • Ecological and technical significance of chlorine and sulfur release is discussed. [ABSTRACT FROM AUTHOR]

Recirculation of hydrothermal carbonization (HTC) process water (PW) has been revealed as an effective strategy to promote the recovery of lost dissolved organics in the spent solvent. However, the role of operating parameters such as temperature, time and solid load during recirculation needs to be clarified and better investigated in order to achieve a successful PW valorization. In this paper, the effects of different reaction conditions during HTC with PW recirculation were studied by using orange peel waste as feedstock. The results showed that strong synergistic interactions occurred between the biomass and the recycled solvent, leading to a hydrochar mass yield increase between 0.5 and 11 wt% on a dry basis (d.b.), according to the reaction conditions. PW recirculation, especially at low conversion severity and solid load, increased hydrochar carbon content while drastically reduced the oxygen fraction. The reason was probably related to promoted dehydration and decarboxylation. As result, carbon and energy yields were respectively increased by 26.1 % and 27.0 %, on average. The energy balance outcomes showed that the energy recovery rose up to 8 times by recycling PW compared to phases with deionized water as HTC solvent. [Display omitted] • Hydrochar recovery enhancement is obtained by solvent recirculation. • Intense synergistic effects in hydrochar formation occur at low temperatures. • Dehydration and decarboxylation are promoted by solvent recycling. • Hydrochar carbon retention is increased by 6.2 % after recirculation at 180 °C. • Process water recirculation improves the conversion energy efficiency. [ABSTRACT FROM AUTHOR]

Abstract This paper provides a comprehensive review of 48 studies on the Life Cycle Assessment (LCA) of biogas production from 2006 to 2018 (13 years). The scope of the study, type of feedstock and impact categories used in the reviewed studies were discussed. Although various studies have been carried out to assess the efficiency and potential of wastes for biogas production, however, little attention has been paid particularly in the developing countries to conduct comprehensive analysis related to the environmental performance of biogas generation based on the LCA methodology. In Malaysia, the utilization of palm oil mill effluent (POME) as the source of energy has recently been expanded due to its abundant production at the palm oil mills. Therefore, this paper also highlights and discusses the feasibility of LCA approach on biogas production from POME as well as the opportunities and challenges from the Malaysian perspective. Highlights • Utilization of biogas production from organic waste to provide a clean energy. • Environmental performance of biogas as a renewable energy using an LCA methodology. • The trends of LCA approach in biogas production was reviewed worldwide. • The opportunities of biogas production from POME in Malaysian was discussed. • The feasibility of LCA approach on biogas production in Malaysian was discussed. [ABSTRACT FROM AUTHOR]

The application of compressed biogas (CBG) in day-to-day livelihood has garnered significant attention in modern day era. It is considered as a potential solution to curb the increasing energy demand and other environmental concerns. The process involves anaerobic digestion (AD) (hydrolysis, acidogenesis, acetogenesis and methanogenesis) of organic substrate under an optimum operating condition (pH, temperature, etc.) via anaerobic microorganisms. This paper aims to describe some major facts about different technological options related to pre-treatment, AD, cleaning and up-gradation system. It also highlights the practical challenges related to high investment cost, inadequate infrastructure, clearance and approval issues, poor feedstock supply chain management etc. in adaption of CBG plants in India. The review examines the significance of both dry and wet continuous digester systems, which includes its advantages and challenges, considering factors, such as feedstock characteristics, process stability, and operational efficiency. It was also found that the type of feedstock and its availability in existing market plays a vital role in smooth functioning of CBG plants. Therefore, the study presents a comprehensive review discussing potential feedstock readily available for CBG plants in Indian market. It was concluded that the usage of agricultural waste (such as Napier grass) has higher CBG potential compared to other feedstock. At the same time, the study presents a broader aspect to policy makers and governing authorities to reframe the existing structure for financial assistantship, regulatory laws, subsidiary schemes etc. for CBG plant owners. It also gives an opportunity to technocrats, industrialist and investors to come-up with an indigenous technology with in-house manufacturing units to promote CBG production in India. [Display omitted] • India has 46 compressed biogas plants with an overall capacity of 272 tonnes/day. • Elaborated the significance of both dry and wet continuous digester systems. • Setting-up a compressed biogas plants requires high investment and operational cost. • Potential market for bio-fuels and bio-fertilizer needs to be explored in India. • Existing financial assistantship and subsidiary schemes need transformation. [ABSTRACT FROM AUTHOR]

The European Union has set ambitious targets of raising the share of EU energy consumption produced from renewable resources from 20% by 2020 to 27% by 2030. The aim of this paper is to assess the role of woody biomass in renewable energy as gross final energy consumption in the European Union (the EU-28). The paper identifies leading and lagging countries in biomass development by focusing on their current biomass use and forecasts future perspectives. The research compares and evaluates the role of biomass in renewable energy in the EU-28 focusing on countries' potential resources and policy support. The study shows that all countries are making efforts to reach the 20% target in 2020 and exhibit a trend of increasing renewable energy as gross final energy consumption towards the new target of 2030. Solid biomass plays an important role in reaching the EU's renewable energy targets. The majority of the EU-28 countries are close to reaching their national renewable energy targets and show a very attractive biomass development. Unless energy consumption decreases however, some member states will face serious problems in reaching their renewable energy target in 2020. Following our analysis, the largest problems occur in those MS having a relative high-energy consumption pattern: France, Germany and the United Kingdom. It is unlikely that they can comply with expected renewable energy demand, unless they mobilize more woody biomass from their available domestic potential (France, Germany) or considerably increase their woody biomass imports (mostly wood pellets) from elsewhere (United Kingdom). [ABSTRACT FROM AUTHOR]

Abstract The rapid development of remote sensing (RS) technology enables an increased usage of high - resolution, spatial, temporal or spectral, data to extract vegetation information, improve model parameters, and estimate energy crop biomass accurately. Five estimation methods developing with RS information for energy crop biomass are summarized in this paper. Firstly, the statistical analysis with vegetation index can be regarded as the commonest method. But it is faulted for the deficiency of sample data and the vulnerability to the influence of many factors such as cloudy days. Secondly, the longer wavelength makes SAR information popular for crop biomass estimation. But many limitations lead to measurement uncertainty and bring about poor classification. Thirdly, NPP can directly reflect accumulated biomass production through photosynthesis and measure the consequences caused by climate change and human activities. But, actual LUE, the results of environmental stresses such as light intensity, temperature, water, and nutrients, is usually considered as a constant. Fourthly, crop height information is vitally important for biomass estimation. Yet the corresponding application is often subject to many factors e.g. crop variety, growth period, and farmland management practices limits. Lastly, the most promising approach lies in the possibility of assimilating state variables from RS data into CGMs. And the advent of latest instruments with better characteristics offer a unique chance to overcome current limitations. In the end, the main challenges and opportunities for energy crop biomass estimation using RS information in the future are listed. Highlights • Increasingly, remote sensing data is being used to estimate energy crops biomass. • Five estimation methods developing with remote sensing information are summarized. • Each estimation method has the strengths and weakness. • As the commonest method, the statistical analysis with VI has obvious drawbacks. • The most promising approach is to assimilate state variables from RS data into CGMs. [ABSTRACT FROM AUTHOR]

Abstract Renewable energy is expected to gain a larger share in the Indonesian energy mix by 2025. Biogas has not only the potential to contribute significantly to the country's renewable energy targets by mid-century, but also to provide a series of co-benefits to improve wellbeing of vulnerable rural communities. The challenge is to find pathways for biogas to overcome well-established technologies and practices in the current heavily fossil fuel based energy system. This paper focused on household-level biogas development in Bali, Indonesia, critically analysing four domestic biogas programmes that are currently under implementation. For our analysis, we adopted an integrated approach combining the multi-level perspective framework with a system-mapping exercise. Moreover, a series of semi-structured interviews as well as an interactive workshop was conducted which allowed us to place multiple stakeholder perspectives and experiences at the heart of the analysis to look at factors beyond the micro-system of the technology, and understand the broader socio-institutional context. Our analysis of enabling and hindering factors to biogas expansion identified opportunities for improving the design and implementation of policy, finance and technology measures. These findings are relevant not only for the Indonesian context, but also for other developing countries that are increasingly investing in transitioning to low-carbon energy futures. Highlights • Barriers to biogas adoption mainly found in policy sector, access to finance and capacity building. • Overcoming barriers is possible by improving steps in market chain and with right policies. • Focusing on co-benefits, creating ownership and build capacity amongst adopters will be crucial. [ABSTRACT FROM AUTHOR]

Abstract Energy access in Sub-Saharan Africa (SSA) remains a challenging issue at the midway point to the United Nations' development goals. From the perspective of energy efficiency and diversification of power-generation sources, this paper investigates the capacity of the wood-processing industry to contribute to the decentralised power generation by performing a techno-economic analysis of the use of wood residues for cogeneration. Using a survey performed in Cameroon as a case study, a biomass-fuelled cogeneration scheme and a model analysing its viability are proposed for the specific context of SSA. A sensitivity analysis indicates for a given process efficiency of the industry, the attractiveness of cogeneration as the processing capacity and feed-in tariffs of electricity increase. More specifically, the threshold of feed-in tariffs ensuring the economic viability of CHP in the sub-region is estimated at $0.15 per kWh for mills where the output capacities of sawn timber products are of 5000 cubic metre per annum and more. The power-generation potential from the primary processing of timbers in the sub-region is about 388 kWh per cubic metre of sawn wood, while the energy intensity of the sawing process is estimated at 132 kWh per cubic metre. Therefore, the industry can generate up to 2472 GWh of electricity in the three sub-regions of East, West and Central Africa if a total of US$ 2.5 billion is invested, allowing a substantial increase of 1% of the current electricity-generation capacity for the geographic location which has the most important forestry resources on the continent. Highlights • Wood-processing residues can contribute significantly to the distributed power generation in African forestry regions. • Energy patterns and the biomass feedstocks from wood-processing industries in Sub-Saharan Africa is comprehensively analysed. • The condensing-extraction steam turbine appears to be the most suitable technology for wood-fired CHP in Sub-Saharan Africa. • A model analysing the viability of industrial wood-fired CHP in the particular context of Sub-Saharan Africa is provided. • Key barriers to the development of waste-wood-fuelled CHP in Sub-Saharan Africa are identified. [ABSTRACT FROM AUTHOR]

Due to its abundance, wood is the pre-eminent lignocellulosic raw material for a sustainable bioeconomy based society. Wood is widely used as fuel, construction material, and raw material in cellulose and lignocellulose based products. Besides the established uses of wood powder, like co-firing with coal and biofuel production, there are also novel uses and process applications, e.g., advanced wood-plastic composites and biochemical production are emerging for which the pulverization or fine grinding of wood is an essential pre-treatment step. Due to the tenacious nature of the wood matrix, size reduction is an energy intensive process and thermal or chemical pre-treatment may be needed to improve economy. This paper provides a broad overview of the fine grinding of wood. First, wood breakage mechanisms and the mechanisms of size reduction are presented, followed by fine grinding techniques and wood pre-treatment methods. A comparison of the specific energy consumption of wood fine grinding in both a gaseous and liquid environment is illustrated. Additionally, examples are given of the role played by pre-treatment methods in decreasing energy consumption. The particle aspect ratio is discussed briefly. Finally, the use and requirements of wood powders in various applications are discussed. [ABSTRACT FROM AUTHOR]

The growing economic importance of the biomass-for-bioenergy in Europe motivates research on biomass supply chain design and planning. The temporally and geographically fragmented availability of woody biomass makes it particularly relevant to find cost-effective solutions for biomass production, storage and transportation up to the consumption facility. This paper addresses tactical decisions related with optimal allocation of wood chips from forest residues at forest sites to terminals and power plants. The emphasis is on a “hot-system” with synchronized chipping and chips transportation at the roadside. Thus, decisions related with the assignment of chippers to forest sites are also considered. We extend existing studies by considering the impact of the wood chips energy content variation in the logistics planning. This is a key issue in biomass-for-bioenergy supply chains. The higher the moisture content of wood chips, the lower its net caloric value and therefore, a larger amount of chips is needed to meet the contracted demand. We propose a Mixed Integer Programming (MIP) model to solve this problem to optimality. Results of applying the model in a biomass supply chain case in Finland are presented. Results suggest that a 20% improvement in the supplier profit can be obtained with the proposed approach when compared with a baseline situation that relies on empirical estimates for a fixed and known moisture content in the end of an obliged storage age. [ABSTRACT FROM AUTHOR]

Several recent life cycle assessments (LCA) of biomass densification have been carried out. This paper reviews data from 19 sources with 48 case scenarios to assess the current status of LCA of biomass densification. It describes the specific units in a reference “gate-to-gate” LCA in relation to the existing studies, and summarises key differences between them. Finally, it provides a qualitative analysis of the associated sources of uncertainty. Existing LCA studies of biomass densification were found to provide insufficient and inconsistent information for full transparency and comparability, due to different choices in system boundary, functional unit, allocation procedure, densification technology and biomass residues. Most of the reviewed studies attributed most of the energy use and greenhouse gas (GHG) emissions to transportation, drying and densification. The energy and GHG emissions of the gate-to-gate densification system were highly sensitive to the technology, feed material used in densification and scale of production. Apart from one study with zero energy consumption as a result of the use of manual operations, the normalised values of energy consumption for the reviewed studies ranged from 20 to 900 kJ MJ −1 . Neglecting three outlier values, GHG emissions as mass of CO 2 -eq for the reviewed studies ranged from 600 t MJ −1 to 50 g MJ −1 . Similar variations in result and outlier cases have beesn reported for other bioenergy processes, by other authors. Assuming that the biggest impact of densification processes is on transport fuel use, and based on 5 studies that reported densification ratios, the net energy and GHG emissions savings resulting from densification ranged from 200 to 1000 kJ MJ −1 and 9 to 50 CO 2 -eq (g MJ −1 ), respectively. On this basis, it can be concluded that biomass densification is a worthwhile addition to the biomass energy conversion system. There is a need for more transparent reporting and analysis of uncertainty in the modelling, to better understand the wide variation in outcomes. [ABSTRACT FROM AUTHOR]

Worldwide environmental policies demand each time more biofuel consumption and less emission. In this context, this work presents a 2G ethanol study as a mean to increase bioethanol production and availability. Currently, technologies use sugarcane bagasse for lignocellulosic ethanol production, which may unbalance the ethanol and sugar mill energy matrix, since bagasse and straw are the main fuel for power and steam generation. A possible solution is using biogas produced from vinasse biodigestion as a fuel instead of using biomass, enabling to shift a fraction of the sugarcane bagasse to 2G ethanol production and, at the same time, keeping power and steam production constant. This paper assesses that energy shift by analyzing ten different scenarios for power generation, comparing the amount of bagasse shifted, the increase in straw consumption, the increase in ethanol production and the reduction of environmental emissions in each scenario. The results show that, at least from the technical and environmental perspective, a combined cycle operating at a high pressure is the best alternative. It is possible to shift from 56.5% to 100% of the available bagasse using the combined cycle technology, which is also followed by an increase in straw consumption. In addition to that, the ethanol availability increase ranges from 28.5 to 50.4%. Moreover, the organic load disposal to the ground also decreases more than 90% compared to the conventional process due to the introduction of vinasse biodigestion. [ABSTRACT FROM AUTHOR]

The paper presents a novel thermodynamic modeling approach of a pilot solar biomass system for bio-methane energy production and wastewater treatment by creation of two packages (STSB and MHPB) modeling platform under TRNsys studio software. Indeed, several newly developed mathematical schemes using the communicating elements: a new Multi-stage air to water Heat Pump, a new Vacuum Tube solar Collector (VTC), thermodynamic storage, and a biogas reactor) have been validated by experiment. The work presents and discusses two scenarios (packages), the first one –STSB- concerns the pilot solar-biomass system, and uses only renewable energy for the bio-methane production by anaerobic digestion mechanism under the mesophilic conditions (±35 °C to ±42 °C), The second scenario consists of a modeling Multi-stage Heat Pump Biomass reactor (MHPB). The packages developed have been tested for industrial case study. A validation process of two scenarios with experimental tests of a 500 L reactor -for the biomass of the cardboard paper-proves a good agreement, where the errors band is about 1% for STSB and 1.5% for the MHPB package. The biogas reactor treats about 900 (m3/year) liquid biomass (3 m3/day). The prediction results indicate that the biogas production attaint 51 (m3) per year. According to the biogas composition analysis, the bio-methane represents 74%, leading to prediction results of 38 (m3) per year of bio-methane for the case study.. Further, the extended results from the modeling packages platform indicate that for this installation type of 700 m3, the bio-methane (CH4) production is estimated of 52 836 (m3) per year, representing 64% of the total fuel consumption for the current case of cardboard recycling and packaging company. • Two free packages (STSB and MHPB) was developed for simulation the solar biogas process. • An experimental validation process of the two packages proves a good agreement of less than 1% for STSB and 1.5% for MHPB. • The reliability of the two packages was demonstrated under the climatic conditions input of 1 min as a time step over a complete one year. • The solar bio-methane reactor unit achieved a satisfactory annual thermal efficiency of 58% for all considering cases and 42% as an efficiency conversion of biogas production. [ABSTRACT FROM AUTHOR]

This paper makes projections of the theoretical and technical potentials of bioenergy supply for 2050. The projections consider changes in available land for bioenergy and food for the global demand and advancements in yield, productivity, expansion of bio-waste recovery, and energy conversion. We present a literature review on projections. We introduced a novel logical and transparent forecasting model. Three future scenarios were established: business as usual (BUS), optimistic trends (OPT), and full adaptation response (FAR). The projection is carried out based on four adjusting factors. An uncertainty analysis was carry-out based on a Monte-Carlo method. Projections of bioenergy production in 2050 were compared with other projections in the literature. The FAR scenario showed that it would be possible to produce twenty-one times the current primary bioenergy supply and to even supply all global primary energy demand in 2050, mostly by energy crops. The assumptions adopted for the BUS and OPT scenarios make their projections more likely. Therefore, the contribution of bioenergy in the global energy matrix is expected to be between 64 and 313 EJ (7.5%–37%) in 2050. There would be a significant change in the composition of the bioenergy supply from today's mostly firewood to energy crops and biowastes. The technical potential for fuel and electric power mostly follow the supply trends for primary bioenergy (theoretical). The potential avoided greenhouse emissions are estimated. The heuristics and the level of transparency of the novel model will allow adjustments and exploration of other scenarios as time passes. • Novel model for projections of the potential of global primary bioenergy supply. • Bioenergy supply potential is shown for 11 different groups of biomass. • Global primary bioenergy supply could increase up to 6 times by 2050 (37% of demand). • Full adaptation response scenario could meet 100% of the global energy demand. • Bioenergy can play a major role in the global energy supply. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The objective of the research work, reported in this paper is, to design and develop a down draft gasifier based power generation system of 75 KWe. A heat exchanger was designed and installed which recycles the waste heat of the hot gas, to improve the efficiency of the system. An improved ash removal system was introduced to minimize the charcoal removal rate from the reactor, to increase the gas production efficiency. A detailed analysis of the mass, energy and elemental balance is presented in the paper. The cold gas efficiency of the system is increased from 75.0% to 88.4%, due to the improvements made in the ash removal method. The Specific Fuel Consumption (SFC) rate of the system is 1.18 kg kWh−1. The energy conversion efficiency of the system, from fuel wood to electric power was found to be 18%. Significant increase in calorific value of the producer gas was achieved by supplying hot air for gasification. [Copyright &y& Elsevier]

High initial viscosity in the high-solids (>15% (w/v)) enzymatic hydrolysis of lignocellulose is problematic especially in stirred tank reactor concepts. One potential way to avoid the high viscosity is the fed-batch feeding of lignocellulosic material to the reactor. In the current study the hydrolysis of filter paper with final concentration of 19.1% (w/w) was evaluated with different fed-batch procedures. Feeding was based on visual observation, stepwise feeding and the power requirement of the stirrer motor. All the fed-batch procedures resulted in similar yields within 30 h (47–49%) which were higher than with the batch process in similar reactor (38%). However, the mixing behavior was superior in the power based feeding as the instantaneous power of the stirrer motor was kept lower (<10 W) than in other fed-batch procedures (>20 W). The power controlled procedure was further evaluated with different enzyme doses, tip speeds and the power levels of substrate feed. Further study showed that the power controlled feeding is applicable also to other hydrolysis and mixing conditions if power levels of substrate feed are set correctly. Higher (15 FPU/g) enzyme dose caused shorter feeding time (3.0 ± 0.5 h) and lower energy consumption during the feeding period (14 ± 3 Wh) compared with lower (5 FPU/g) enzyme dose (7.0 ± 1.3 h and 33 ± 5 Wh, respectively). The tip speed and the power level of substrate feed had fewer effect on these factors. The performance of the hydrolysis process can thus be enhanced by the substrate feed controlled by the power of the stirrer motor. [ABSTRACT FROM AUTHOR]

Abstract: Malaysia has an abundance of energy resources, both renewable and non-renewable. The largest non-renewable energy resource found in Malaysia is oil, and second, is natural gas, primarily liquefied natural gas. The production and consumption of oil, gas and coal in Malaysia are given in this paper. The energy demand and supply by source are also shown in relation to the country’s fuel diversification policy. In order to reduce the overall dependence on a single source of energy, efforts were undertaken to encourage the utilization of renewable resources. Forest residue and oil palm biomass are found to be potentially of highest energy value and considered as the main renewable energy option for Malaysia. Palm oil and related products represent the second largest export of Malaysia. The total oil palm planted area in Malaysia has increased significantly in recent years. This paper gives a detailed representation of oil palm planted and produced together with its yield from the year 1976 onwards. The large amounts of available forest and palm oil residues resulting from the harvest can be utilized for energy generation and other by-products in a manner that also addresses environmental concerns related to current waste disposal methods. [Copyright &y& Elsevier]

The population of Mozambique''s capital Maputo relies to a large extent on wood fuel to meet its energy needs. The paper, based on a sample of 168 non-domestic and 240 domestic consumers, shows that domestic households constitute the most important wood fuel users in the city. Domestic consumption is now between 0.9 and 1.0 m3 of woody biomass per capita, an increase of more than 10% compared to data from the 1980s. This increase occurs despite a growing importance of alternatives such as paraffin, gas and electricity, and can be explained by the substitution of firewood by charcoal. The paper also shows a strong correlation between fuel consumption and socio-economic factors such as household size, area of residence and income. A striking feature is that similar to poorer families higher income households tend to use charcoal in combination with non-woody fuels, contradicting FAO''s (1993) “fuel ladder”. The paper argues finally that the importance of social economic factors inflicts a dynamism on fuel consumption patterns, which makes it necessary to monitor them on a regular instead of an ad hoc basis, as is the case now. [Copyright &y& Elsevier]

The demand for renewable energy is increasing due to increasing energy consumption and global warming associated with increasing use of fossil fuels. Hydrogen gas is considered as a good energy carrier due to its high energy content. Biomass (e.g. agricultural and forestry residues, food industry wastes, and energy crops) is amenable to dark fermentative hydrogen production. However, lignocellulosic materials require pretreatment and/or hydrolysis prior to dark fermentation. This paper reviews potential biomass sources for hydrogen fermentation as well as the effects of different pretreatment and hydrolysis methods on sugar yields as well as hydrogen yields from hydrolyzates. The effects of process parameters on dark fermentative hydrogen production from lignocellulosic hydrolyzates are also discussed. [ABSTRACT FROM AUTHOR]

Biomass gasification based building cooling, heating, and power (BCHP) system is an effective distributed energy system to improve the utilization of biomass resources. This paper proposes a combined methodology of optimization method and life cycle inventory (LCI) for the biomass gasification based BCHP system. The life cycle models including biomass planting, biomass collection-storage-transportation, BCHP plant construction and operation, and BCHP plant demolition and recycle, are constructed to obtain economic cost, energy consumption and CO2 emission in the whole service-life. Then, the optimization model for the biomass BCHP system including variables, objective function and solution method are presented. Finally, a biomass BCHP case in Harbin, China, is optimized under different optimization objectives, the life-cycle performances including cost, energy and CO2 emission are obtained and the grey incidence approach is employed to evaluate their comprehensive performances of the biomass BCHP schemes. The results indicate that the life-cycle cost, energy efficiency and CO2 emission of the biomass BCHP system are about 41.9 $ MWh-1, 41% and 59.60 kg MWh-1 respectively. The optimized biomass BCHP configuration to minimize the life-cycle cost is the best scheme to achieve comprehensive benefit including cost, energy consumption, renewable energy ratio, steel consumption, and CO2 emission. [ABSTRACT FROM AUTHOR]

The paper discusses alternatives for biofuel-based district heating using simulation analysis in a real-life case example. First, the paper illustrates the current supply chain structure of forest chips from harvest to the heat energy plant. Usually the chips are naturally dried, chipped on the roadside and transported to the heating plant based on the orders. Second, the study demonstrates how a regional bioenergy system could be developed with the help of a simulation model for evaluating the feasibility of different wood fuel supply chain options. The model mimics a real-life example of an industrial area in a small Finnish municipality planning to invest in a CHP plant. The results show that the investment in a CHP plant and use of artificially dried wood fuel can be profitable in the circumstances where local demand exists for heat energy. The simulation-based vision can be compared with the presently dominant concept of highly decentralized supply chains for wood chips that is widely used among energy suppliers. However, to optimize the transportation costs and the moisture content of the chips changes are needed in the supply chain processes and structure. The results of this study are useable for practical decision-making and offer useful ideas for continuing research on alternative ways to produce energy wood biomass in the future. • Supply chain of forest chips in Finland is presented. • A real-life case of an industrial area demostrating how a regional bioenergy system could be developed is presenting. • The simulation model created minics the real-life case. • Feasibility of different wood fuel supplu chain options are discussed. [ABSTRACT FROM AUTHOR]

Supercritical water oxidation (SCWO) is an effective, promising technology for destroying almost all kinds of organic waste with the advantage of high removal efficiency and low residence time, and without producing pollutant byproduct. The chemical energy of organic pollutants can be considered as an emerging renewable energy source. As a high-temperature and pressure process, an immense energy demand is required in the pressurization and preheating sections. On the other side, the reactor effluent has a great potential for energy recovery because of the great amount of heat released during the SCWO reaction combined with the previous energy input. Thus, SCWO is not only an organic waste treatment process but also an energy conversion and utilization system. The application of SCWO has been extended to the clean, efficient utilization of low-quality fuels such as high-sulfur coal, heavy oils, and biomass instead of conventional combustion, hydrothermal spallation drilling in geothermal energy production, and heavy oil recovery. However, energy consumption cost is still rather high in the actual process due to insufficient equipment performance, unreasonable energy system integration, and selection of an anti-corrosion and salt plugging reactor. Thus, a systematic, in-depth analysis on energy conversion and utilization in SCWO is conducted for the first time in the paper. The mechanism of exergy destruction analyses indicates that reducing enthalpy change and energy level difference are critical to reducing energy consumption. Suggestions on improving energy efficiency are proposed in the preheating stage, chemical exergy release, and reactor design. [Display omitted] • Energy conversion and utilization in each stage of an SCWO system are analyzed. • Research methods and evaluation parameters for energy utilization are summarized. • Main factors affecting energy efficiency are summarized and analyzed. • The mechanism of exergy destruction is analyzed to reduce energy consumption. • Suggestions on improving energy efficiency are proposed. [ABSTRACT FROM AUTHOR]

Abstract: China has become increasingly dependent on the international energy market owing to the rapid growth of demand for energy. To develop renewable energy and thus strengthen energy security for the future, it is important to consider the potential of crop residues. This paper contributes to this topic by mobilizing up-to-date statistical and remote-sensing data and by carrying out a geographic and economic analysis. Its assessment shows that China's total output of crop residues in 2010 amounted to 729 million tons, and the quantity could be used for commercial energy production is between 147 and 334 million tons, depending on the competition power of the commercial energy production relative to the traditional uses of crop residues. The analysis also shows that the distribution of crop residues in China is highly uneven. By taking into account the densities of crop residues available for energy production at the grid-cell level, the transportation cost constraints, and the economy-of-scale requirements of energy plants, this study further assesses the geographic distribution of the suitability for establishing crop residue based power plants and bioenergy plants in China. [Copyright &y& Elsevier]

Abstract: Microalgae have been recognized as one of the most promising biomass sources of energy, in particular for bio-fuels production. In this paper the production of bio-oil from a fast growing microalgae species with low lipids content is proposed. The influence of both the cultural medium and the reaction conditions on bio-oil yields and quality is investigated performing fixed and fast pyrolysis tests on Chlorella vulgaris grown in complete and nitrogen starved medium. Nitrogen starvation leads to a higher lipids amount in the biomass, increasing its calorific value. Fast pyrolysis of nitrogen starved microalgae is proposed to achieve high bio-oil yield and quality. In this case, experiments have pointed out a maximum bio-oil yield of about 72% mass on dry basis at 400 °C. Bio-oil products were characterized on the basis of GC–MS, elemental analysis and calorific content. In particular, the GC–MS analysis accounts for an oily fraction of the bio-oil formed by several hydrocarbons as well as oxygenated and nitrogenous species, including indoles, fatty acids and alcohols. The bio-oil produced from nitrogen starved biomass exhibits higher amount of fatty acids and lower amount of nitrogenous species, resulting in an improved quality. Furthermore, the higher lipids amount of the nitrogen starved biomass leads to a major carbon content in the bio-oil and thus to a slight increase of its calorific value. For all the experimental tests the energy consumption ratio was calculated, and fast pyrolysis of nitrogen starved biomass has proved to be the most convenient process in the energetic valorization of microalgae. [Copyright &y& Elsevier]

Abstract: China’s forest bioenergy policies are evolving against the backdrop of pressing national energy challenges similar to those faced by OECD countries, and chronic rural energy challenges more characteristic of developing countries. Modern forest bioenergy could contribute to solutions to both of these challenges. However, because of limitations in current technologies and institutions, significant policy and resource commitments would be required to make breakthroughs in either commercializing forest bioenergy or modernizing rural energy systems in China. Given the potential attention, funding, and resource trade-offs between these two goals, we provide an argument for why the focus of China’s forest bioenergy policy should initially be on addressing rural energy challenges. The paper concludes with a discussion on strategies for laying the groundwork for a modern, biomass-based energy infrastructure in rural China. [Copyright &y& Elsevier]

Abstract: In this paper, we analyze the determinants of the demand for firewood by Norwegian households, focusing on intrinsic factors such as lifestyle and environmental attitudes, along with household socioeconomic characteristics. The data are from the Norwegian Consumer Expenditure Survey and a supplementary questionnaire on energy consumption and lifestyle. We apply a zero-inflated negative binomial model to correct for overdispersion and the excessive number of zeros in the data. The results indicate that an urban lifestyle and concerns for comfort are negatively associated with firewood demand. In addition, price has a strong negative effect on demand. However, the most important determinants of household firewood demand are the characteristics of the household residence, including location, and household characteristics such as age and income. [Copyright &y& Elsevier]

Abstract: The aim of this study is to evaluate the potential use of biodiesel produced from waste cooking oil (WCO) in Mexico and its CO2 emission reduction potential for the Mexican transport sector and associated costs. The results show, based on 2010 data, that the potential of biodiesel from WCO is between 7.8 PJ and 17.7 PJ that represent between 1.5% and 3.3% of petro-diesel consumption for the road transport sector and can reduce between 0.51 and 1.02 Mt of CO2, (1.0%–2.7% of CO2-associated emissions), depending on the recovery ratio of WCO from vegetable oil consumption for cooking and considering CO2 emissions for biodiesel production and methanol emissions during production and combustion in the blend. Primary energy used to produce 1 MJ of WCO-biodiesel is 0.8727 MJ, while literature reports 1.2007 MJ to produce 1 MJ of petro-diesel. Biodiesel costs are similar to petro-diesel costs if WCO is free. The paper offers suggestions for policies that promote increased recollection of WCO for biodiesel production and reduced illegal marketing of WCO, which is the main barrier to increase biodiesel production from WCO. The data used for the analysis is based on a case study of a WCO biodiesel plant that operates in Mexico City. [Copyright &y& Elsevier]

The significant growth aviation has been observing is increasing the sector's pressure on the environment; in the EU28, passengers travelling by air in 2016 increased of 5.9% compared to 2015. The aviation industry voluntarily committed to significant aspirational goals, and identified bio-based aviation fuels as a potential means to improve its environmental performance. Despite of that, the market penetration of aviation biofuels in EU28 is almost negligible. In this paper, an assessment of the likely aviation biofuels demand has been carried out, under a baseline scenario of increasing total fuel consumption of +3% for 2016–2020 and + 3.5% up to 2030; the CO 2 intensity of this growth has been calculated accordingly. Europe is a World leader in biofuel technologies; the current potential aviation biofuels is based on the HVO/HEFA technology, and the upper limit of the installed capacity can be considered approximately 2.4 Mt y−1. Nevertheless, lower production volumes can be expected as production plants are today optimized for road fuel production, not aviation. By 2025 the situation may change, with a total production capacity of 3.5 Mt y−1, and with an average potential production for aviation biofuels ranging 0.5–2 Mt y−1. The paper shows that even if today's EU nominal capacity appears large enough to support the expected aviation biofuels demand, other bottlenecks may limit the real market uptake: availability of sustainable feedstocks, competition with demand for road transport sector, etc. For this reason, a comparison of the cost for CO 2 saving of other potential solutions to mitigate aviation's climate impact has also been carried out. • The paper estimates the current EU28 nominal HVO/HEFA installed capacity, in about 2.3 Mt y−1. • A lower value can be expected for aviation biofuels (355 kt y−1), as production is today optimized for road biofuels. • Biofuels to meet aviation carbon neutral growth would account for 16% of the current EU total biofuel demand. • Availability of sustainable feedstock may constitute a bottleneck for the sector. • The costs comparison for CO 2 saving, between biofuel and ETS allowance, seems to favour the latter. [ABSTRACT FROM AUTHOR]

Abstract Chipping weighs heavily on the total delivered cost of wood fuel, which calls for accurate chipping cost estimates. Chipper repair and maintenance cost is perhaps the most obscure among the figures required for a reliable estimate of chipping cost. To clarify this issue, the authors examined the long-term repair and maintenance records for 51 wood chippers operated by 48 chipping service contractors. Repair and maintenance represented between 1.5% and 29% of total chipping cost, inclusive of fuel and labour (mean = 14%). The ratio between total accumulated repair (TAR) cost and machine price averaged 32% and varied with total use. The relationship between total use and TAR to price ratio was explored through regression analysis, which produced a very strong model (R2 = 0.8). This model predicts a TAR to price ratio of 0.64 at 10000 h, with no significant differences between tractor-driven and independent-engine machines. While the coefficients are different, the structure of this model offers a good match with the repair and maintenance cost models developed for farm tractors and other agricultural machinery. A second model was developed for estimating repair and maintenance cost as a function of fuel consumption. The study also provides reference figures for the contribution of labour cost to total maintenance cost. Farm tractors incur more repairs than preventive maintenance, contrary to the other dedicated components of the chipping operation, where preventive maintenance represents most of maintenance cost. Forestry users should make allowance for the lower structural strength of tractors and select large models. Highlights • Long-term maintenance records were obtained for 51 wood chippers. • Maintenance is 14% of chipping cost on average, and ranges between 1.5 and 29%. • At 10000 h, total accumulated repair (TAR) cost amounted to 60% of machine price. • A model was developed for predicting TAR as a function of total use. • Maintenance was also estimated as a function of fuel consumption. [ABSTRACT FROM AUTHOR]

Abstract: Biofuel production has been promoted to save fossil fuels and reduce greenhouse gas (GHG) emissions. However, there have been concerns about the potential of biofuel to improve energy efficiency and mitigate climate change. This paper investigates energy efficiency and GHG emission saving of cassava-based ethanol as energy for transportation. Energy and GHG balances are calculated for a functional unit of 1 km of road transportation using life-cycle assessment and considering effects of land use change (LUC). Based on a case study in Vietnam, the results show that the energy input for and GHG emissions from ethanol production are 0.93 MJ and 34.95 g carbon dioxide equivalent per megajoule of ethanol respectively. The use of E5 and E10 as a substitute for gasoline results in energy savings, provided that their fuel consumption in terms of liter per kilometer of transportation is not exceeding the consumption of gasoline per kilometer by more than 2.4% and 4.5% respectively. It will reduce GHG emissions, provided that the fuel consumption of E5 and E10 is not exceeding the consumption of gasoline per kilometer by more than 3.8% and 7.8% respectively. The quantitative effects depend on the efficiency in production and on the fuel efficiency of E5 and E10. The variations in results of energy input and GHG emissions in the ethanol production among studies are due to differences in coverage of effects of LUC, CO2 photosynthesis of cassava, yields of cassava, energy efficiency in farming, and by-product analyses. [Copyright &y& Elsevier]

Abstract: This paper investigates the short-run and long-run causality analysis between biomass energy consumption and economic growth in the selected 10 developing and emerging countries by using the Autoregressive Distributed Lag bounds testing (ARDL) approach of cointegration and error correction models. It covers annual data from 1980 to 2009. The cointegration test results show that there is cointegration between the biomass energy consumption and the economic growth in nine of the ten countries (Argentina, Bolivia, Cuba, Costa Rica, El Salvador, Jamaica, Nicaragua, Panama, Paraguay, Peru). The cointegration test results show that there is no cointegration between the biomass energy consumption and the economic growth in one of the ten countries (Paraguay). [Copyright &y& Elsevier]

Abstract: This paper presents the life cycle inventory (LCI) of hydrogen production by Clostridium butyricum fermentation of Scenedesmus obliquus hydrolysate. The main purpose of this work was to evaluate the potential of H2 production from microalgal biomass and the respective energy consumption and CO2 emissions in the bioconversion process considering the microalga production, acid hydrolysis of S. obliquus biomass, preparation of the inoculum and culture media, and fermentation. The scale-up to industrial production was not envisaged. The hydrogen yield obtained in this work was 2.9 ± 0.3 mol H2/mol sugars in S. obliquus hydrolysate. Results show that this process of biological production of hydrogen can achieve 7270  of energy consumption and 670 . The microalgal culture is the stage responsible for 98% of these total final values due to the use of artificial lighting. All stages and processes with the highest values of energy consumption and CO2 emissions were identified for future energetic and environmental optimisation. [Copyright &y& Elsevier]

Abstract Currently different trade units are used throughout the forest energy supply chain in Sweden: chipping contractors are paid per m3 chipped volume, dry metric tonnes or MWh, hauliers per raw tonnes or m3 chipped volume and the company supplying the chips to the heating plant most often per delivered MWh. This introduces business risks for all market players, and affects studies of chipping equipment. Lately, Skogforsk has used oven dry tonnes, but stakeholders that measure chips in other units want results to be presented in these units as well. To raise awareness about output unit selection and its effect on productivity and fuel consumption studies, Bruks 806 chippers were studied when chipping spruce and beech residues. Results show that the selection of output unit affects the capacity of detecting treatment differences and the direction of such differences. Chipping productivity based on effective chipping time was higher for spruce residues when calculated using chipped volume, and for beech when calculated using raw weight. Similar trends were found for fuel consumption per product unit. As both feedstock characteristics and output measurement unit selection affects study results, a proper experimental design to control these effects is important. In many cases it is a matter of keeping feedstock constant during comparisons of machines/treatments. Care is needed when using chipped volume, as chipper settings may influence chip bulk density and thus chip volume. The use of different units throughout the supply chain reduces transparency and increases the risk for sub-optimal decisions. Highlights • Output unit affects the possibility to detect differences in chipper efficiency. • The direction of treatment differences may depend on the choice of output unit. • Output unit choice is an issue when comparing feedstocks or published results. • Effects of output unit choice can be controlled by a proper experimental design. [ABSTRACT FROM AUTHOR]

Abstract: The life cycle greenhouse gas (GHG) and fossil fuel benefits of black liquor recovery are analyzed. These benefits are due to the production of energy that can be used in the pulping process or sold, and the recovery of the pulping chemicals that would otherwise need to be produced from other resources. The fossil GHG emissions and non-renewable energy consumption of using black liquor in the kraft recovery system are approximately 90% lower than those for a comparable fossil fuel-based system. Across all scenarios, the systems relying on black liquor solids achieve a median reduction of approximately 140 kg CO2 eq./GJ of energy produced, compared to the systems relying on fossil fuels to provide the same energy and pulping chemical production functions. The benefits attributable to the recovery of pulping chemicals vary from 44% to 75% of the total benefit. Applied to the total production of kraft pulp in the U.S., the avoided emissions are equivalent to the total Scopes 1 and 2 emissions from the entire U.S. forest products industry. These results do not depend on the accounting method for biogenic carbon (because biogenic CO2 emissions are the same for the systems compared) and the results are valid across a range of assumptions about the displaced fossil fuel, the GHG-intensity of the electricity grid, the fossil fuels used in the lime kiln, and the level of cogeneration at pulp and paper mills. The benefits occur without affecting the amount of wood harvested or the amount of chemical pulp produced. [Copyright &y& Elsevier]

Abstract: This paper presents the results of thermodynamics modelling studies of a 2 kW (e) biomass-fired CHP system with organic Rankine cycle (ORC). Three environmentally friendly refrigerants, namely HFE7000, HFE7100 and n-pentane, have been selected as the ORC fluids. The thermodynamic properties of the selected ORC fluids which have been predicted by commercial software (EES) are used to predict the thermal efficiency of ORC. The results of modelling show that under the simulated conditions (1) the ORC thermal efficiency with any selected ORC fluid is well below (roughly about 60% of) the Carnot cycle efficiency; the ORC efficiency depends on not only the modelling conditions but also the ORC fluid – the highest predicted ORC efficiency is 16.6%; the predicted ORC efficiency follows the following order: n-pentane > HFE7000 > HFE7100 (2) both superheating and sub-cooling are detrimental to the ORC efficiency (3) the electrical efficiency of the CHP system with the selected ORC fluids is predicted to be within the range of 7.5%–13.5%, mainly depending on the hot water temperature of the biomass boiler and the ORC condenser cooling water temperature as well as the ORC fluid, and corresponding to about 1.5 kW and 2.71 kW electricity output (4) the overall CHP efficiency of the CHP system is in the order of 80% for all three ORC fluids although the amount and quality of heating supplied by the CHP system depend on the ORC fluid selected and the modelling conditions. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a techno-economic study into the feasibility of a number of biomass-fuelled CHP (BCHP) systems when operated in a community housing/mixed use context. Six systems comprising differing technologies have been analysed, with the assumption that the systems operate within an ESCO (energy services company) supply scenario. Actual demand data was obtained for a representative community housing scheme, along with technical performance and cost data on the various biomass CHP systems. Subsequently, an economic modelling tool was developed and a number of operational scenarios were analysed to determine the viability of specific systems and the sensitivity of the results to a range of technical and economic parameters. The impact of thermal storage was also considered in order to optimise heat usage as far as possible. The results indicate that within specific realistic ESCO operating scenarios, biomass CHP can demonstrate positive net present values without the need for capital subsidies. Optimal system design and implementation is critical for profitable operation and it is found that the best economic performance occurs for high load factors when the maximum quantity of both electricity and heat sold on-site is maximised. The results are also found to be very sensitive to a number of the model inputs. [Copyright &y& Elsevier]

Abstract: Increased use of pellets has resulted in a shortage of the traditional raw materials required for pellet making, including saw dust, shavings and cuttings from saw mills. Therefore, the pellets industry has started to look for alternative raw materials. Limited consumption of pulpwood from Scots pine (Pinus sylvestris L.) in Norway has made it a potential raw material for the pellets industry. A study on how bark content affects the quality of pellets is reported in this paper. Pellets from pinewood containing zero, five, 10, 30 and 100 percent bark were produced, and their quality parameters were evaluated. Combustion tests were also performed on the produced pellets. Pellets made from pure bark had the best mechanical properties compared with pellets made of wood containing various concentrations of bark. The differences were not substantial and the durability for all chosen assortments was in the same quality class in the CEN standard. A positive effect off the amount of steam added was found. The bulk densities of the blend pellets were higher than those of pure wood and bark. The ash content increased with the amount of bark in the pellets. There were no problems with sintering when the bark content was low (five and 10 percent). For pure bark pellets some sintering was registered. [Copyright &y& Elsevier]

Abstract: A review of the four main wood energy sectors in the U.S. was conducted to explore historic trends and the impact of alternative energy prices and public policies on wood energy consumption. High oil prices have triggered the adoption of government regulation and financial incentives to promote greater use of wood energy over the last four decades. However, the amount of wood energy consumed in the U.S. industrial sector was driven mainly by the output of the pulp and paper products industry and not by energy prices or any particular public policy incentive. Residential consumption of wood energy was positively correlated with competing energy prices. Public policies seem to have had a greater impact on wood energy consumption in the electric power sector and over the last four decades have concentrated on promoting biopower with a recent shift to liquid cellulosic biofuels. High oil prices and a series of public policies such as tax credits, loans, grants, and renewable energy standards have resulted in higher consumption of wood energy from 2004 to 2009 in the residential, electric power and commercial sectors by an estimated 5, 2, and less than 1 percent annually, respectively. The impact of new federal programs such as the Biomass Crop Assistance Program remains to be observed. Continuation of public incentives and preferential regulations for renewable energy appears to be necessary for a steady increase in U.S. wood energy consumption. [Copyright &y& Elsevier]

Abstract: Biodiesel is an alternative fuel that is cleaner than petrodiesel. Biodiesel can be used directly as fuel for a diesel engine without having to modify the engine system. It has the major advantages of having high biodegradability, excellent lubricity and no sulfur content. This paper presents the results of investigations carried out in studying the fuel properties of soybean methyl ester (SME) and its blend with marine diesel fuel from 5%, 20% and 50% blends by volume and in running a diesel engine with these fuels. The results indicate that the use of biodiesel produces lower smoke opacity (up to 74%), but higher brake specific fuel consumption (BSFC) (up to 12%) compared to marine fuel (MF). The measured carbon monoxide (CO) emissions of B5 and B100 fuels were found to be 3% and 52% lower than that of the MF, respectively. [Copyright &y& Elsevier]

Abstract: In this paper the fuel ethanol production from empty fruit bunches was experimentally evaluated using alkaline pretreatment and enzymatic hydrolysis for sugars release. Fermentation was accomplished using a native Saccharomyces cerevisiae strain. Ethanol concentration was carried on using a glass bench-scale distillation column. Experimental results were used for planning and designing the process scheme using Aspen Plus. Process simulation allowed calculating the mass and energy balances. It was found that coupling alkaline pretreatment with a later autoclaving improved the sugars yield in enzymatic hydrolysis. However, the use of the remaining soaking solution from pretreatment as hydrolysis medium had negative effects on sugars yield suggesting that there exist inhibit substance for the enzyme. Better results for enzymatic hydrolysis were obtained when sodium acetate buffer was used. Ethanol yield obtained from both experiments and simulation were very similar (66.50 and 65.84 dm3 of ethanol per each t of empty fruit bunches, respectively). These low ethanol yields were obtained because the native S. cerevisiae does not assimilate all reducing sugars, suggesting that those sugars were pentoses. Simulated alkaline and autoclaving pretreatment contributed only with 2% of the total energy consumption (198.4 GJ m−3 ethanol) while product recovery represented 57% of the total energy. [Copyright &y& Elsevier]

Abstract: This paper assesses the sustainable biomass resource for energy in China. Assessment has been carried out for the following resources: (i) agricultural residues, (ii) forest residues, and (iii) municipal solid waste (MSW). The potential of each resource is estimated for the base years 2008, 2008, and 2007. The energy potentials of these resources in 2008, 2008, and 2007 are estimated to be 14.7, 3.9, and 0.2EJ, respectively. The total potential including the energy of 6.4EJ from the proposed low-input high-diversity (LIHD) grassland biomass on the untilled lands for the base years 1996 is equal to about 30.2% of China’s energy consumption in 2008. Furthermore it is projected that sustainable biomass use for energy will reduce net emissions of green house gases (GHG) of 3276.7 million tonnes, and help in emission-reduction target of China and the world. [ABSTRACT FROM AUTHOR]

Abstract: The process of fuel ethanol production from cassava root is connected to a chain of impacts on the water resource of the country where the cassava plant is grown and the root processed into fuel ethanol. The paper assesses the impact of the domestic production of 5 per cent ethanol (E5) needed under the Nigerian biofuel programme from cassava root on the water resource of Nigeria. Using the 2007 Premium Motor Spirit (PMS) consumption as the baseline, Nigeria will require about 0.49 hm3 of ethanol to blend 9.32 hm3 of PMS to arrive at the 2007 consumption estimates. The impact of the domestic production of this ethanol requirement translates to about 6.0 km3 of water; out of which about 48 per cent is green and about 52 per cent is blue. Addressing future impact typical of a developing economy like Nigeria, a three-scenario analysis was adopted to examine the impact of future growth in cassava-fuel ethanol requirement on the water resource of Nigeria, and also, the impact of improved water use on the future water footprint of E5. The projected water impact of cassava-ethanol production into the future ranges from 6.02 to 7.28 km3, while improved water use could lower these values by about 0.04–2.35 km3 for the same period, 2010 to 2020, under the projection assumptions made. [Copyright &y& Elsevier]

Abstract: The environmental and social sustainability of biofuel production and use is today the most critical issue for the development of support policies in this sector.The Life Cycle Assessment (LCA) methodology is commonly agreed as the main tool for the estimation of the impact of biofuel chains, even in quantitative terms. This is also reflected in the recently issued EU Directive (Renewable Energy Directive, RED) on the promotion of the use of energy from renewable sources. However, the results of Life Cycle Assessment works largely depend on the quality of the information given as input to the study, as also very recent research works started to investigate: in addition, the comparison of a large number of very different (technically, geographically, agronomically) biofuel chains, as some Life Cycle Assessments and reviews tried to do, is a very difficult task due to the extremely large number of variable conditions and parameters. This paper, by considering a very specific biofuel chain (production and use of Pure/Straight Sunflower Oil in North-Central Italy), discuss some limits and constraints of the application of the LCA method. The work investigated within which boundaries Life Cycle Assessment could be implemented to perform quantitative assessments, as requested by the current supporting policies in the biofuel area. Results showed very large variations in the calculation of the CO2 equivalent emissions, thus illustrating how achievable results depends on the local agricultural practices and performances, even for such a small and well defined biofuel chain. The adoption of the present standardized Life Cycle Assessment approach for generalized evaluations in the bioenergy sector and, in particular, for quantitative assessments should therefore be reconsidered. Concluding, LCA studies, even while addressing very specific and well defined chains, should always provide the bias of the calculations, as this range of variation of Life Cycle Assessment results could be significantly greater than the initially set quantitative targets and therefore the whole investigation would be at risks of inconsistency. Proposals are finally given for small scale projects, with the aim of developing sound but realistic processes to assess biofuel sustainability. [Copyright &y& Elsevier]

Abstract: Reduction of the emissions of greenhouses gases, increasing the share of renewable energy sources (RES) in the energy balance, increasing electricity production from renewable energy sources and decreasing energy dependency represent the main goals of all current strategies in Europe. Biomass co-firing in large coal-based thermal power plants provides a considerable opportunity to increase the share of RES in the primary energy balance and the share of electricity from RES in gross electricity consumption in a country. Biomass-coal co-firing means reducing CO2 and SO2, emissions and it may also reduce NO x emissions, and also represents a near-term, low-risk, low-cost and sustainable energy development. Biomass-coal co-firing is the most effective measure to reduce CO2 emissions, because it substitutes coal, which has the most intensive CO2 emissions per kWh electricity production, by biomass, with a zero net emission of CO2. Biomass co-firing experience worldwide are reviewed in this paper. Biomass co-firing has been successfully demonstrated in over 150 installations worldwide for most combinations of fuels and boiler types in the range of 50–700MWe, although a number of very small plants have also been involved. More than a hundred of these have been in Europe. A key indicator for the assessment of biomass co-firing is intrduced and used to evaluate all available biomass co-firing technologies. [Copyright &y& Elsevier]

Abstract: Where and when farmers will adopt new energy crops is a key issue for the proper development of a country''s energy strategy on renewables based in bioenergy. This paper analyses the spread of willow cultivation for bioenergy in Sweden, during the period 1986–2005, linked to the changes in the policies of promotion of wood-energy crops and to the local economic framework. To perform the study, a geostatistic method based on kernel analysis is applied, in order to identify the spatial grouping patterns of growers and plantations, and the areas where cultivation was successful. The analysis of the resulting figures shows that the development of an infrastructure and a market for willow chips are essential pre-conditions for the development of short rotation coppice for bioenergy. The results of this study confirm that probably the most important factor in the location of willow plantations is the existence of consumers that can guarantee a long-term demand for willow chips. The tools and methods presented, and its analysis, can provide a better understanding of the interactions between the biomass producers, the energy consumers and the different local and national actors. [Copyright &y& Elsevier]

Abstract: With an outlook for higher global energy prices and concomitant increase of agricultural resources for the pursuit of fuel, consumers are expected to seek more fuel-economic transportation alternatives. This paper examines factors that influence the importance consumers place on fuel economy, with attention given to differences between American and European consumers. In a survey conducted simultaneously in the United States (U.S.) and Belgium in the fall of 2006, respondents in both countries ranked fuel economy high among characteristics considered when purchasing a new vehicle. Overall, respondents in the U.S. placed greater emphasis on fuel economy as a new-vehicle characteristic. Respondents'' budgetary concerns carried a large weight when purchasing a new vehicle as reflected in their consideration of a fuel''s relative price (e.g. gasoline vs. diesel vs. biofuel) and associated car repair and maintenance costs. On the other hand, high-income Americans displayed a lack of concern over fuel economy. Concern over the environment also played a role since consumers who felt empowered to affect the environment with their purchasing decisions (buying low and clean emission technology and fuels) placed greater importance on fuel economy. No statistically significant effects on fuel economy rankings were found related to vehicle performance, socio-demographic parameters of age, gender or education. Importantly, the tradeoff between using agricultural inputs for energy rather than for food, feed and fiber had no impact on concerns over fuel economy. Finally, contrary to expectations, U.S. respondents who valued domestically produced renewable fuels did not tend to value fuel economy. [Copyright &y& Elsevier]

Abstract: Since the year 2000 or so there has been a rapid growth on fuel ethanol production and consumption, particularly in US and Brazil. Ethanol trade represented about 10% of world consumption in 2005, Brazil being the main exporter. The most important consumer markets—US and European Union (EU)—have trade regimes that constrained the comparative advantages of the most efficient producers, such as Brazil. This paper evaluates the fuel ethanol market up to 2030 together with the potential for international biotrade. Based on forecasts of gasoline consumption and on targets and mandates of fuel ethanol use, it is estimated that demand could reach 272Gl in 2030, displacing 10% of the estimated demand of gasoline (Scenario 1), or even 566Gl in the same year, displacing about 20% of the gasoline demand (Scenario 2). The analysis considers fuel ethanol consumption and production in US, EU-25, Japan, China, Brazil and the rest of the world (ROW-BR). Without significant production of ethanol from cellulosic materials in this period, displacing 10% of the gasoline demand in 2030, at reasonable cost, can only be accomplished by fostering fuel ethanol production in developing countries and enhancing ethanol trade. If the US and EU-25 reach their full production potential (based on conventional routes), the minimum amount that could be traded in 2030 would be about 34Gl. Displacing 20% of the gasoline demand by 2030 will require the combined development of second-generation technologies and large-scale international trade in ethanol fuel. Without second-generation technologies, Scenario 2 could become a reality only with large-scale production of ethanol from sugarcane in developing countries, e.g., Brazil and ROW-BR could be able to export at least 14.5Gl in 2010, 73.9Gl in 2020 and 71.8Gl in 2030. [Copyright &y& Elsevier]