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The need to use renewable sources and matrices with energy potential is widely recognized. The development of innovative technologies aimed at the improvement of energy conversion processes and reducing environmental impacts is currently receiving increasing attention from the scientific community and policymakers. The presence of sugars in airborne particle materials is attributed to biomass combustion. For this reason, these compounds are considered markers of biomass burning. The purpose of this work was to evaluate the emissions produced by agroforestry biomass burning (citrus pruning) by simultaneously sampling both stack emissions and atmospheric particulates in the area around a biomass boiler to understand the real contribution of biomass burning to atmospheric pollution. The combustion tests were carried out by comparing the processes with and without particulate abatement system to see how biomass combustion's contribution to particulate emission can be controlled and reduced. During the tests, the focus was on particulate matter (PM) speciation in terms of sugar marker identification and determination. This study aims to increase knowledge to better understand the contribution of biomass plants to air pollution and differentiate it from the contributions of other sources, such as vehicular traffic or domestic heating. [ABSTRACT FROM AUTHOR]

Bamboo has been identified as a promising solution to the energy crisis and climate change as a source of biomass energy. Due to its rapid growth and high‐value products, bamboo is considered as a potential source of biomass energy. Bamboo contains a significant amount of cellulose and hemicellulose, which can be converted to sugar constituents, making it an ideal raw material for energy production. This article reviews the different processes of producing bioethanol, biogas, biochar, and bio‐oil from bamboo biomass using techniques such as pyrolysis, hydrothermal liquefaction, fermentation, and anaerobic digestion, and discusses the opportunities and challenges of these conversion technologies. It also reviews the main types and morphological characteristics of energy bamboo species and proposes an evaluation system for energy bamboo species, which optimizes the utilization efficiency of bamboo biomass energy and maximizes benefits by adopting appropriate methods for producing bioenergy based on the characteristics of different bamboo species. [ABSTRACT FROM AUTHOR]

The bibliometric analysis investigated the impact of publications on trends in the literature and bioenergy research using artificial intelligence (AI) from 1991 to 2021. In this study, 1721 publications were extracted from the Web of Science, and an analysis of the countries, authorship, institutions, journals, and keywords was visualised. In the recent decades, this field has entered an outbreak phase. India was the most productive country in this area, followed by China, Iran, and the US. It also noted several notable differences between trends and subjects in developed and developing countries. The former led this field at the initial stage and later attached importance to using AI for research feedstock and impact assessment. Developing countries encouraged the advancement of this area and emphasised the feedstock usage of phase treatment and process optimisation. In addition, a co-authorship and institutes study revealed that authors and institutes in distant regions rarely collaborated. The journal analysis shows strong links between Energy, Fuel, and Energy Conversion and Management. Machine learning is by far the most common application of artificial intelligence (AI) technology in bioenergy research, with 53% of the articles using it. In these AI-related publications, the keyword artificial neural network (ANN) appeared most frequently in the articles. [ABSTRACT FROM AUTHOR]

Simultaneous hydrogen, ethanol, and 1,3-propanediol (1,3-PD) production from pure and crude glycerol were performed under thermophilic conditions (55 ± 4 °C). The effect of the organic loading rate (25, 37.5, 50, 62.5, and 75 g/L-d) on the formation of hydrogen, ethanol, and 1,3-PD was investigated. Maximum hydrogen yields of 2.90 and 2.05 mol-H 2 /mol-glycerol were achieved with OLR of 62.5 g/L-d of pure and crude glycerol. 1,3-PD yields of 0.32, 0.36 mol/mol-glycerol and ethanol yields of 0.19, 0.22 mol/mol-glycerol were achieved with the optimum OLRs using pure and crude glycerol. Ethanol production at 50.77 and 51.09 mmol/L was achieved at OLRs of 37.5 and 75 g/L-d, respectively, using pure and crude glycerol as substrates while the hydrogen and 1,3-PD yields of 1.08 and 1.69 mol-H 2 /mol-glycerol and 0.32 and 0.36 mol/mol-glycerol were obtained from these optimal OLRs. COD balance under optimum OLR using pure and crude glycerol as the substrate indicates that 1,3-PD and hydrogen were the main products followed by ethanol. The energy conversion efficiency for hydrogen, 1,3-PD, and ethanol was 34.87, 39.54, 17.88%, respectively. Enterobacter sp., Klebsiella sp. , and K. pneumoniae , were found as the simultaneous hydrogen, ethanol, and 1,3-PD producing bacteria presence in pure and crude glycerol fermentation. Image 1 • H 2 , EtOH, 1,3-PD were produced from crude glycerol under thermophilic conditions. • UASB reactor was operated at OLRs of 50, 62.5, and 75 g/L-d. • H 2 , 1,3-PD, and EtOH achieve 92.29% energy conversion efficiency. • Enterobacter sp., Klebsiella sp. produced H 2 , 1,3-PD, and EtOH simultaneously. • Changing OLR influences the NADH/NAD+ ratio which resulted in variety of products. [ABSTRACT FROM AUTHOR]

• This study provides a thermo-kinetic approach on peanut shell pyrolysis. • Pyrolytic breakdown of solid peanut shell is independent of the heating rate. • This study helps to predict the extent of conversion at certain temperature. • Pyrolysis primarily involve breaking intra-molecular and intra-particle bonds. • Pyrolytic breaking of pseudo-components in peanut shell follow first-order law. This study focuses on the thermo-kinetic analysis of solid peanut shell waste, through dependence of the activation energy with the conversion degree. Three model-free kinetics, Kissinger (K), Friedman (Fr) and Kissinger-Akahira-Sunose (KAS), were applied to thermogravimetric (TGA) data to calculate the effective activation energy E α during a pyrolysis process. The results obtained by Kissinger's method showed that the pyrolytic breakdown pathway of hemicellulose, cellulose, and lignin in a ligno-cellulosic biomass is independent of the heating rate and can be described through a simple first-order kinetic reaction (f (α) = 1 − α). The thermo-kinetic behavior obtained by isoconversional methods (Fr and KAS) of the hemicellulose degradation shows a progressive and monotonic increase in E α with the conversion, between ~140 and ~195 kJ mol−1 with an average value of 172 kJ mol−1, which reveals the competitive character of the process (multi-step process). Conversely, in the cellulose degradation, the dependence of E α on α , shows the typical behavior of a reaction controlled by a single rate-determining step, with constant average E α values of ~209 kJ mol−1. Meanwhile, the lignin pyrolytic degradation shows an increase in E α from ~220 up to ~300 kJ mol−1 with the conversion, indicating that this stage is kinetically controlled by an energy barrier that comprises multiple and simultaneous processes. Finally, the kinetic analysis confirmed the absence of autocatalytic reactions (thermally auto-catalyzed process) during the pyrolysis, although the global process is highly exothermic. [ABSTRACT FROM AUTHOR]

Torrefaction is a thermal conversion method extensively used for improving the properties of biomass. Usually this process is conducted within a temperature range of 200-300 °C under an inert atmosphere with residence time up to 60 minutes. This work aimed to study the kinetic of thermal degradation of oil palm frond pellet (OPFP) as solid biofuel for bioenergy production. The kinetics of OPFP during torrefaction was studied using frequently used iso-conversional model fitting (Coats-Redfern (CR)) and integral model-free (Kissinger-Akahira-Sunose (KAS)) methods in order to provide effective apparent activation energy as a function of conversion. The thermal degradation experiments were conducted at four heating rates of 5, 10, 15, and 20 °C/min in a thermogravimetric analyzer (TGA) under non-oxidative atmosphere. The results revealed that thermal decomposition kinetics of OPFP during torrefaction is significantly influenced by the severity of torrefaction temperature. Via Coats-Redfern method, torrefaction degradation reaction mechanism follows that of reaction order with n = 1. The activation energy values were 239.03 kJ/mol and 109.28 kJ/mol based on KAS and CR models, respectively. [ABSTRACT FROM AUTHOR]

This paper surveys the status and future prospects of bioenergy renewable energy source (RES) hybrids, i.e. energy conversion processes that have at least two renewable energy inputs, one of which is bioenergy. Finland, Austria, Germany and Denmark were the case study countries. We found that the implementation of bioenergy RES hybrids was already ongoing in various sectors, but a majority of them was focused on domestic heating applications. Bioenergy can be used to provide flexible resources for both energy supply and energy storage. An important motivation behind hybrid systems is the possibility of switching between different energy sources in an optimal way. No significant technical limitations were identified for surveyed hybrid systems, but the future economic potential of bioenergy RES hybrids remains difficult to estimate as the value of flexibility cannot be assessed in isolation from the energy system. © 2019 The Authors. Biofuels, Bioproducts, and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The limited success in the promotion of biomass use through technologically advanced heating networks in economically depressed areas has been, in part, attributed to the insufficient understanding of the transformation patterns of the energy for use of indigenous resources. In this regard, Organic Rankine cycle (ORC) is proved to be reliable technology that can efficiently convert resources into useful power by thermal machines. The present study has the aim to study the conversion of energy by implementing a district micro-cogeneration system using Organic Rankine Cycle (ORC) technology in mining areas. For this purpose, the region of Valdeorras (Spain) has been selected as a study area based on the functional character of its mining area. The methodology used allows for analysis of the resource, technology and the management of the conversion of energy during the different phases in a process of analytical hierarchy. Additionally, a nodal macro network is set in the study area that covers part of the electrical as well as thermal demand with indigenous resources. The nodal micro-cogeneration unit operates by heat-match mode and generates electricity and heat, 200 kW e and 1.9 MW th , respectively, by supply of 2.6 MW th by biomass combustion. • An innovative solution by nodal network of district heating is defined. • The implementation of units of micro-cogeneration in nodes can be achieved. • The feasibility of exploiting the bioenergy through micro-cogeneration is analysed. • The defined energy systems produce economic, social and environmental benefits. [ABSTRACT FROM AUTHOR]

Highlights • A new method for the assessment of the water–food–energy nexus is developed. • The quantification of the WFE nexus is operated through an efficiency-type index. • The new index assesses the interrelationship among water and land use and the food production in bioenergy production. • The method is applied to assess the efficiency of biofuel production on the global scale and from the main crops used. Abstract This paper assesses the sustainability of bioenergy production under a nexus perspective through a new efficiency type index. The index describes 1st generation biofuel production under the perspective of the implied consumption of natural resources. We consider the sustainability of energy production as a sequence of steps, each characterised by its efficiency, and propose an index which returns an overall efficiency value describing the adequacy or inadequacy of the considered processes under a nexus perspective. The direct application of the nexus index entails an indication of the possible improvements needed to move production towards most sustainable processes or places. Moreover, it allows evaluating the efficiency of the main crops currently used in biofuel production with respect to the water–food–energy nexus. The results depict countries presently capable of performing sustainable production of 1st generation biofuel from particular crops. Furthermore, the analysis of the single components of the nexus index allows understanding the effects of possible improvements (e.g. soil and water management, new generation biofuels) on the overall production efficiency under a nexus perspective. [ABSTRACT FROM AUTHOR]

The cultivation of energy cane throughout the Southeastern United States may displace grazed pastures on organic soil (Histosols) to meet growing demands for biofuels. We combined results from a field experiment with a biogeochemical model to improve our understanding of how the conversion of pasture to energy cane during early crop establishment affected soil GHG (CO 2 , CH 4 , and N 2 O) exchange with the atmosphere. GHG fluxes were measured under both land uses during wet, hot and cool, dry times of year, and following a fertilization event. We also simulated the impact of changes in precipitation on GHG exchange. Higher fertilization of cane contributed to greater emission of N 2 O than pasture during warmer and wetter times of the year. The model predicted that energy cane emitted more nitrogen than pasture during simulated wetter than drier years. The modeled emission factor for N 2 O was 20 to 30-fold higher than the default value from IPCC (1%), suggesting that the default IPCC value could dramatically underestimate the consequences of this land conversion on the climate system. Predicted soil CH 4 and CO 2 fluxes were higher in pasture than energy cane, and this difference was not affected by increasing precipitation. Model simulations predicted that soils under first year cane emit more GHGs than pasture, particularly during wet years, but this difference disappeared two years after energy cane establishment. Our results suggest that management practices may be important in determining soil GHG emissions from energy cane on organic soils particularly during the first year of cane establishment. [ABSTRACT FROM AUTHOR]

The use of woody biomass in thermochemical conversion is still the most popular method of obtaining bioenergy from this material. Elemental composition has a significant effect on biomass quality and parameters of the combustion process. The aim of this study was to determine the content of selected macroelements (phosphorus, potassium, magnesium, calcium, sodium and sulphur), microelements (boron, copper, iron, manganese and zinc) and trace elements (cadmium, chromium, nickel and lead) in willow biomass of two different varieties and three clones, harvested in annual, biennial and triennial cycles in north-eastern Poland. The study found significant variability between varieties/clones and harvest cycles. Biomass of the UWM 200 clone of Salix alba in triennial harvest rotation had the best parameters as a potential fuel source; it was found to contain the significantly smallest concentrations of P, K, Na, S (1.48, 5.45, 0.08, 0.35 g kg −1 DM, respectively) and Fe, Cr, Pb (208.85, 4.91, 0.83 mg kg −1 , respectively). The content of all of the elements under study decreased significantly with an extended harvest cycle, and the differences, when comparing the triennial to the annual cycle, ranged from −9% to −29% for macroelements, from −7% to −48% for microelements and from −11% to −20% for trace elements. [ABSTRACT FROM AUTHOR]

Global energy sectors are facing the crucial challenge of sustainability and diversification of energy resources. Seeking renewable resources with a sustainable supply is therefore a matter of the utmost concern. In this respect, bamboo, a renewable lignocellulosic material and non-food biomass, has great potential to be utilized to produce energy. Several studies have been conducted on a wide range of bamboo species and the results have shown that bamboo could potentially be used as a suitable fuel because it shares desirable fuel characteristics present in other woody biomass. Bamboo can be used as an energy source by converting it into solid, liquid, and gaseous fuels. However, to utilize bamboo as a high promise energy crop resource for biofuels, a secure and stable supply is required. Therefore, additional information on the availability, cultivation, and harvesting operations of bamboo is vital to ensure the practicability of the idea. The objective of this review is to highlight the potential of bamboo as an alternative source of bioenergy production, particularly in a Malaysian context, with emphasis on the concepts, pretreatment, and conversion technologies. [ABSTRACT FROM AUTHOR]

The ongoing debate about costs and benefits of wood-pellet based bioenergy production in the southeastern United States ( SE USA) requires an understanding of the science and context influencing market decisions associated with its sustainability. Production of pellets has garnered much attention as US exports have grown from negligible amounts in the early 2000s to 4.6 million metric tonnes in 2015. Currently, 98% of these pellet exports are shipped to Europe to displace coal in power plants. We ask, 'How is the production of wood pellets in the SE USA affecting forest systems and the ecosystem services they provide?' To address this question, we review current forest conditions and the status of the wood products industry, how pellet production affects ecosystem services and biodiversity, and what methods are in place to monitor changes and protect vulnerable systems. Scientific studies provide evidence that wood pellets in the SE USA are a fraction of total forestry operations and can be produced while maintaining or improving forest ecosystem services. Ecosystem services are protected by the requirement to utilize loggers trained to apply scientifically based best management practices in planning and implementing harvest for the export market. Bioenergy markets supplement incomes to private rural landholders and provide an incentive for forest management practices that simultaneously benefit water quality and wildlife and reduce risk of fire and insect outbreaks. Bioenergy also increases the value of forest land to landowners, thereby decreasing likelihood of conversion to nonforest uses. Monitoring and evaluation are essential to verify that regulations and good practices are achieving goals and to enable timely responses if problems arise. Conducting rigorous research to understand how conditions change in response to management choices requires baseline data, monitoring, and appropriate reference scenarios. Long-term monitoring data on forest conditions should be publicly accessible and utilized to inform adaptive management. [ABSTRACT FROM AUTHOR]

This study examines the advantages of incorporating a terminal for forest biomass in an advanced biofuels supply chain network. Forest biomass as a feedstock is non-uniform, voluminous and high in moisture content (MC). This leads to inefficiencies during transportation and energy conversion process, posing a challenge for supply chains to remain profitable. The problem is exacerbated by seasonality in both supply and demand. A terminal in the biomass feedstock supply chain could help overcome these challenges, but adds a significant cost. A novel multi-period mixed-integer programming (MIP) model capable of taking into consideration biomass quality, seasonality, and weather related supply restrictions was developed. The model was applied in a case study to assess the benefits of incorporating a terminal in the supply chain. It was demonstrated that a terminal allowed delivery of feedstock 4–11% lower in MC, while reducing procurement costs by 11–32%. The benefits reported are sensitive to transportation and operating costs. The proposed model will serve as a valuable tool for practitioners to design supply chains, and assess the feasibility of using forest biomass for sustainable biofuels production. [ABSTRACT FROM AUTHOR]

Success and acceptability of the bio energy conversion technology to a large extent depend upon management of the inevitable by-products generated during the conversion process. By-products can be considered favourable as organic fertilizer as they retain nutrients with varying composition depending upon input biomass. However, characteristics of these heterogeneous resources with respect to feedstock and processing conditions have to be assessed to state on their agricultural and environmental benefits. Therefore, 3 types of anaerobic digestion by-products (digestate) from surplus biomass viz. cow dung, Ipomoea carnea:cow dung (60:40 dry weight basis) and rice straw:green gram stover:cow dung (30:30:40 dry weight basis) and one gasification by-product (biochar) from rice husk are considered to understand the fertilizer prospects. Considering 3 potential application options, digestate from each feedstock option was further processed as separated solid, separated liquid and ash from solid digestates. Thus, a total of 10 by-products were investigated for understanding their prospects as fertilizer using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X ray Spectroscopy (EDX) and phyto-toxicity test to have a broad insight in terms of their organic, mineral, elemental composition, morphological feature and potential phyto-toxicity. In general, irrespective of origin of feedstock, solid digestate, ash digestate and char showed similarity in terms of composition of functional groups with some degree of variation in relative content as reflected by FTIR analysis. Dominance of organic functional groups in separated solid digestates compared to liquid fraction indicated the former as favourable organic amendments. Quartz was the prevalent mineral phase in all separated solid, ash digestate and rice husk char. Digestates in ash phase represent more concentrated plant nutrient source with higher content of K, Ca, P, Na and Mg than their respective solid phase. Application of ash digestates and char is likely to improve adsorptive capacity of soil for water and nutrient due to presence of relatively uniformly distributed porous particles. Liquid fraction of Ipomoea digestates exhibited inhibitory effect on seed germination of greengram ( Vigna radiate) with significant reduction of germination index. Inhibitory effects of by-products were found to correlate negatively with their electrical conductivity and ammonia-nitrogen content. Understanding on spectroscopic, morphological and phytotoxic properties of different application options of bioenergy by-products would be useful for assessment of their appropriate use in agriculture. [ABSTRACT FROM AUTHOR]

Bioenergy conversion technologies have been frequently described and analysed in the literature, but a comprehensive and detailed comparison between the complex individual characteristics of each technology is still lacking. Therefore, the paper contains a description of the technical, economic and environmental properties of each technology with a special focus on the German bioenergy sector. The study presents an analysis of different bioenergy applications with regard to their specifications, power/heat output range and their areas of application. Due to the fact, that biomass combustion applications are the most widespread and market proven renewable conversion technologies, a detailed analysis of decentralised, biomass-fired CHP plants is presented in the paper. The overview of the individual characteristics of different biomass conversion routes shows that biogas plants achieve high electrical efficiencies, are available with a broad range of capacities and belong to the established technologies. Although the investment costs of biogas plants are relatively high, biomass conversion with anaerobic digestion can be seen as one of the most promising option for a sustainable energy supply in Europe. [ABSTRACT FROM AUTHOR]

Vast amounts of leaf litter have to be disposed of by city administrations. This biomass has the potential for energy conversion, but contamination with pollutants can adversely affect this usage. We investigated leaf litter samples from the city of Kassel by analyzing their heavy metal and polycyclic aromatic hydrocarbon (PAH) concentrations. Leaf samples were indeed contaminated with heavy metals and PAHs and contamination was influenced by provenience and collection technique. A simple cleaning system of washing and subsequent mechanical dewatering significantly reduced heavy metal concentration. Regression models were developed for contamination with heavy metals which showed that contamination could be successfully estimated using the total ash content of the sample as a predictor, with an R2 of up to 0.77. It can be concluded that leaf litter from cities is a possible feedstock for energetic conversion, provided a cleaning step is applied. [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]

High-diversity mixtures of native tallgrass prairie vegetation should be effective biomass feedstocks because of their high productivity and low input requirements. These diverse mixtures should also enhance several of the ecosystem services provided by the traditional monoculture feedstocks used for bioenergy. In this study, we compared biomass production, year-to-year variation in biomass production, and resistance to weed invasion in four prairie biomass feedstocks with different diversity: one species - a switchgrass monoculture; five species - a mix of C4 grasses; 16 species - a mix of grasses, forbs, and legumes; and 32 species - a mix of grasses, forbs, legumes, and sedges. Each diversity treatment was replicated four times on three soil types for a total of 48 research plots (0.33-0.56 ha each). We measured biomass production by harvesting all plant material to ground level in ten randomly selected quadrats per plot. Weed biomass was measured as a subset of total biomass. We replicated this design over a five-year period (2010-2014). Across soil types, the one-, 16-, and 32-species treatments produced the same amount of biomass, but the one-species treatment produced significantly more biomass than the five-species treatment. The rank order of our four diversity treatments differed between soil types suggesting that soil type influences treatment productivity. Year-to-year variation in biomass production did not differ between diversity treatments. Weed biomass was higher in the one-species treatment than the five-, 16-, and 32-species treatments. The high productivity and low susceptibility to weed invasion of our 16- and 32-species treatments supports the hypothesis that high-diversity prairie mixtures would be effective biomass feedstocks in the Midwestern United States. The influence of soil type on relative feedstock performance suggests that seed mixes used for biomass should be specifically tailored to site characteristics for maximum productivity and stand success. [ABSTRACT FROM AUTHOR]

Perennial, cellulosic bioenergy crops represent a risky investment. The potential for adoption of these crops depends not only on mean net returns, but also on the associated probability distributions and on the risk preferences of farmers. Using 6-year observed crop yield data from highly productive and marginally productive sites in the southern Great Lakes region and assuming risk neutrality, we calculate expected breakeven biomass yields and prices compared to corn ( Zea mays L.) as a benchmark. Next we develop Monte Carlo budget simulations based on stochastic crop prices and yields. The crop yield simulations decompose yield risk into three components: crop establishment survival, time to maturity, and mature yield variability. Results reveal that corn with harvest of grain and 38% of stover (as cellulosic bioenergy feedstock) is both the most profitable and the least risky investment option. It dominates all perennial systems considered across a wide range of farmer risk preferences. Although not currently attractive for profit-oriented farmers who are risk neutral or risk averse, perennial bioenergy crops have a higher potential to successfully compete with corn under marginal crop production conditions. [ABSTRACT FROM AUTHOR]

Nanotechnology has an increasingly large impact on a wide range of biotechnological, pharmacological and pure technological applications. Its current use in bioenergy production from biomass is very limited. This paper examines the potential interrelationships between nanotechnology and bioenergy production through a comprehensive literature review and analysis of data from biomass characterisation studies. The aim of this review is to indicate how nanotechnology can be applied in biomass-to-bioenergy conversion. This study shows currently nanotechnology has been applied in the production of only two types of biomass, i.e. sludge and algae. Hence, interaction of nanomaterials with active sludge and algal cells were examined. Our extensive literature review indicates that anaerobic digestion process in sludge can potentially be enhanced by using magnetite nanoparticles, which gives higher methane yields. On the other hand, nanosilver reduces growth and causes adverse effects on the morphology of green algae. This process for bioenergy generation has already been successfully applied to sludge and algae biomass. Our study confirms that the process can also be used in the production of bioenergy from the other biomasses, such as agricultural wastes and industrial residues. Outcomes of this work will be an important tool for implementing nanotechnology in bioenergy research. [ABSTRACT FROM AUTHOR]

Reliable estimation of fuel consumption in residential sector is crucial for the future development of fuel supply system. Three approaches are compared in this study to capture climate impact, as well as and interfuel substitution between fuels, on residential fuel consumption for space heating in the Nordic countries. The first approach aims at directly estimating the demand for each energy carrier as a function of explanatory variables including heating degree days, fuels price and GDP per capita. The second approach is a two-stage model combing an econometric model for total energy use for space heating, and the market share for energy carriers based on cross/price elasticities, while in the third approach a set of simultaneous equations models were estimated. Based on the results of the mean average error and root-mean-square error criteria for three approaches across the Nordic countries, it was found that the second and third approaches were able to capture the complementary and substitution effects between fuels. This finding confirms our hypothesis that the interfuel substitution is a key factor for estimating changes in fuel demand and should be accounted for when residential energy demand is projected. The results additionally have important implications for climate change policy, by exploring the impact of fuel price on residential energy demand for space heating. [ABSTRACT FROM AUTHOR]

Switchgrass ( Panicum virgatum) is a C perennial grass and is the model herbaceous perennial bioenergy feedstock. Although it is indigenous to North American grasslands east of the Rocky Mountains and has been planted for forage and conservation purposes for more than 75 years, there is concern that switchgrass grown as a biofuel crop could become invasive. Our objective is to report on the invasion of C and C grasses into the stands of two switchgrass cultivars following 10 years of management for biomass energy under different N and harvest management regimes in eastern Nebraska. Switchgrass stands were invaded by big bluestem ( Andropogon gerardii), smooth bromegrass ( Bromus inermis), and other grasses during the 10 years. The greatest invasion by grasses occurred in plots to which 0 N had been applied and with harvests at anthesis. In general, less grass encroachment occurred in plots receiving at least 60 kg of N ha or in plots harvested after frost. There were differences among cultivars with Cave-in-Rock being more resistant to invasion than Trailblazer. There was no observable evidence of switchgrass from this study invading into border areas or adjacent fields after 10 years of management for biomass energy. Results indicate that switchgrass is more likely to be invaded by other grasses than to encroach into native prairies or perennial grasslands seeded on marginally productive cropland in the western Corn Belt of the USA. [ABSTRACT FROM AUTHOR]

Literature values for glucose release from corn stover are highly variable which would likely result in tremendous variability in bio-refinery ethanol yield from corn stover feedstock. A relatively recent change in United States corn genetics is the inclusion of the Bacillus thuringiensis (Bt) trait, which now accounts for three-fourths of all US planted corn acreage. The objective of this study was to evaluate the effect of corn grain yield, inclusion of the Bt trait, and location environment on corn stover quality for subsequent ethanol conversion. Two hybrid pairs (each having a Bt and non-Bt near-isoline) were analyzed giving a total of 4 hybrids. In 2010 and 2011, field plots were located in Michigan at four latitudinal differing locations in four replicated plots at each location. Stover composition and enzymatic digestibility was analyzed and estimated ethanol yield (g g −1 ) was calculated based on hydrolyzable glucan and xylan levels. Analysis showed that there were no significant differences in total glucose or xylose levels nor in enzymatically hydrolyzable glucan and xylan concentrations between Bt corn stover and the non-Bt stover isolines. Regression analyses between corn grain yield (Mg ha −1 ) and corn stover ethanol yield (g g −1 ) showed an inverse relationship indicative of a photosynthate source-sink relationship. Nevertheless, the quantity of stover produced was found to be more critical than the quality of stover produced in maximizing potential stover ethanol yield on a land area basis. [ABSTRACT FROM AUTHOR]

Microalgae have tremendous potential for producing liquid renewable fuel. Many methods for converting microalgae to biofuel have been proposed; however, an economical and energetically feasible route for algal fuel production is yet to be found. This paper presents a review on the comparison of the most promising conversion pathways of microalgae to liquid fuel: hydrothermal liquefaction (HTL), wet extraction and non-destructive extraction. The comparison is based on important assessment parameters of product quality and yield, nutrient recovery, GHG emissions, energy and the cost associated with the production of fuel from microalgae, in order to better understand the pros and cons of each method. It was found that the HTL pathway produces more oil than the wet extraction pathway; however, higher concentrations of unwanted components are present in the HTL oil produced. Less nutrients (N and P) can be recovered in HTL compared to wet extraction. HTL consumes more fossil energy and generates higher GHG emissions than wet extraction, while the production cost of fuel from HTL pathway is lower than wet extraction pathway. There is considerable uncertainty in the comparison of the energy consumption and economics of the HTL pathway and the wet extraction pathway due to different scenarios analysed in the assessment studies. To be able to appropriately compare methodologies, the conversion methods should be analysed from growth to upgradation of oil utilising sufficiently similar assumptions and scenarios. Based on the data in available literature, wet oil extraction is the more appropriate system for biofuel production than HTL. However, the potential of alternative extraction/conversion technologies, such as, non-destructive extraction, need to be further assessed. [ABSTRACT FROM AUTHOR]

A pilot-scale trial of oil and biodiesel production from high-oleic sunflower was performed in Tuscany (central Italy). An experimental investigation was carried out to evaluate the field performance and the product properties and yields of two high-oleic hybrids (PR64 H31 and PR65 H41). The processing facility, a pilot plant with a limited production capacity located in the proximity of the production field, included a platform for oil production and transesterification. The oil yields of the two high-oleic varieties were around 35% with respect to seed weight. The sunflower seed oils obtained fulfilled most of the quality requirements for the use of vegetable oils as engine fuels. The production of biodiesel was carried out in the transesterification unit. However, the production and the direct use of the sunflower seed oil seemed to be a more suitable option than its conversion to biodiesel, especially at a small scale like that considered in this study. The possible exploitation of seed pressing co-product (sunflower cake) as solid biofuel was assessed. The relatively high calorific value (21 MJ kg −1 ) and the low moisture content (<15%) made it an interesting option for thermal applications. Field and process data allowed the evaluation of key performance indicators for the production chain. Biofuel and bioenergy yields as high as 1850 and 3170 kg ha −1 and 68.7 and 59.6 GJ ha −1 were obtained for oil and cake, respectively. Based on these data, different scenarios of fuel and energy production in the rural context of Tuscany were hypothesized. [ABSTRACT FROM AUTHOR]

This paper presents the novel MILP formulation of the Biomass Value Chain Model (BVCM), a comprehensive and flexible optimisation toolkit that models a large number of bioenergy system pathways. The model accounts for the economic and environmental impacts associated with the end-to-end elements of a pathway: crop production, conversion technologies, transport, storage, local purchase, import (from abroad), sale and disposal of resources, as well as CO 2 sequestration by CCS technologies and forestry. It supports decision-making around optimal use of land, biomass resources and technologies with respect to different objectives, scenarios and constraints. Objectives include minimising cost, maximising profit, minimising GHG emissions, maximising energy/exergy production or any combination of these. These objectives are combined with a number of scenarios (such as including different CO 2 prices, different technology and climate scenarios, import scenarios, waste cost scenarios), different credits (e.g. by-product and end-product, CCS and forestry carbon sequestration) and a number of constraints such as minimum levels of energy production and maximum environmental impacts. The toolkit includes an extensive database of different biomass technologies including pretreatment, densification, liquid and gaseous fuel production, heat and power generation (separately or combined, biodedicated or co-fired), waste-to-energy conversion and carbon capture and sequestration. A large number of resources are considered including a variety of bio-resources (e.g. energy crops such as Miscanthus and SRC willow, arable crops such as winter wheat, sugar beet and oilseed rape and short and long rotation forestry), intermediates, products, by-products and wastes. The BVCM is a spatio-temporal model: currently it is configured for the UK using 157 square cells of length 50 km and the planning horizon is from the 2010s to the 2050s, with seasonal variations considered. The framework is data-driven so the model can be easily extended: for example adding new resources, technologies, transport modes, etc. or changing the time horizon and the location to another country is only a matter of changing the data. Results of example UK case studies are presented to demonstrate the functionality of the model. [ABSTRACT FROM AUTHOR]

There is an increasing interest to integrate phototrophic microorganisms into microbial fuel cells (MFCs) to assist electricity generation. In general, this integration can be accomplished in three ways: (1) phototrophic microorganisms function as or provide a substrate for supplying electrons; (2) photoheterotrophic microorganisms catalyze the anode reaction; and (3) photoautotrophic microorganisms provide oxygen as an electron acceptor to the cathode reaction. Direct use of phototrophic microorganisms for electricity production in MFCs faces significant challenges, because of the complex composition of microbial cells and their resistance to hydrolysis, and low conversion efficiency to electric energy by MFCs. Proper pretreatment using chemical or biological methods may improve degradability of microbial cells. Some purple nonsulfur bacteria exhibit strong electrochemical catalysis of organic compounds in the anode of an MFC, and the effect of illumination on the catalytic performance needs further investigation. Electricity generation via syntrophic relationship between photosynthetic microorganisms (providing organic compounds) and heterotrophic bacteria (oxidizing organics) in the anode is generally low due to low concentration of the electron donors and adverse effect of oxygen as a result photosynthesis on anode activities. It is promising to apply photosynthetic microorganisms in the cathode with multiple functions of oxygen supply, nutrient removal and biomass production. To address some of the challenges, two paradigms are proposed to encourage further investigation and development of effective processes with strong synergy between phototrophic microorganisms and MFCs. [ABSTRACT FROM AUTHOR]

Information on the growth and development of warm-season grasses in response to management is required to use them successfully as a biomass crop. Our objectives were to determine optimum harvest periods and effect of N fertilization rates on the biomass production of four warm-season grasses, and to investigate if traits of canopy structure can explain observed yields with varying harvest dates and N rates. A field study was conducted at Sorenson Research Farm near Ames, IA, during 2006 and 2007. The experimental design was split-split plot arranged in a randomized complete block with four replications. Big bluestem ( Andropogon gerardii Vitman), eastern gamagrass ( Tripsacum dactyloides L.), indiangrass ( Sorghastrum nutrans L. Nash), and switchgrass ( Panicum virgatum L.) were main plots. Three N application rates (0, 65, and 140 kg ha−1) were subplots, and 10 harvest dates were sub-sub plots. Biomass of warm-season grasses increased with advanced maturity, but differently among species. The maximum yield of eastern gamagrass occurred at the highest MSC (1.6 and 2.2) when the largest seed ripening tillers were present. Big bluestem, switchgrass, and indiangrass obtained the maximum yields at MSC 3.5, 3.9, and 2.9, respectively when the largest reproductive tillers were present. In terms of a biomass supply strategy, eastern gamagrass may be used during early summer, while big bluestem and switchgrass may be best used between mid- and late- summer, and indiangrass in early fall. Nitrogen fertilization increased yield by increasing tiller development. Optimum biomass yields were obtained later in the season when they were fertilized with 140 kg ha−1. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes and tests novel supply chain designs for bioenergy and biobased products that result in logistical costs savings of 2–38%. The proposed supply chain design reduces the costs of: (1) purchasing logistical harvesting equipment; (2) operating logistical harvesting equipment; and (3) holding feedstock inventory, by using a multitude of crop types as feedstock, instead of just one, as is common in research and practice today. In so doing, this research challenges the prevalent assumption that monocultures, despite their known environmental concerns, are preferable from a costs perspective. Simulation/optimization is used to test supply chain designs, and then to find the environmental conditions where these new supply chain designs could be most profitably implemented. [Copyright &y& Elsevier]

Abstract: The distribution of the wood pellet plants in Europe was analysed using a geo-statistical kernel based approach, in order to identify and define cluster-regions with high concentration of pellet production capacity. For that, a database with the location of pellet plants, as well as its capacity, was constructed, identifying 378 pellet plants with annual capacities over 1000 t, and an aggregated production of 11.5 million t. The geo-statistical methods facilitated the analysis of the plants with regards to their market position at global and local level. At a European level, four main production areas were identified, defined as: “Central Europe” (Bavaria, Austria, and neighbouring areas of France, Switzerland and Italy), “Scandinavia”, “Finland”, and the “Baltic”. These areas concentrated over 50% of the pellet production, although presented different characteristics regarding market establishment and development, their role in the global pellet trade and their raw material availability. The paper provides with methodological tools to identify and characterise the main pellet production areas in Europe that can have further economic and policy applications. [Copyright &y& Elsevier]

Highlights: [•] IFBB effectively increased VS and fibre content in biomasses for combustion. [•] IFBB produced a highly digestible substrate for anaerobic digestion. [•] Gross energy yield for IFBB is in the range of conventional hay combustion. [•] Energy yield was influenced by chemical and botanical parameters in a complex manner. [Copyright &y& Elsevier]

Insufficient spatial coverage of existing land-cover data is a common limitation to timely and effective spatial analysis. Achieving spatial completeness of land-cover data is the most challenging for large study areas which straddle ecological or administrative boundaries, and where individuals and agencies lack access to, and the means to process, raw data from which to derive spatially complete land-cover maps. In many cases, various sources of secondary data are available, so that land-cover map assimilation and synthesis can resolve this research problem. The following paper develops a reliable and repeatable framework for assimilating and synthesizing pre-classified data sets. Assimilation is achieved through data reformatting and map legend reconciliation in the context of a specific application. Individual maps are assessed for accuracy at various geographic scales and levels of thematic precision, with an emphasis on the ‘area of overlap’, in order to extract information that guides the synthesis process. The quality of the synthesized land-cover data set is evaluated using advanced accuracy assessment methods, including a measure describing the ‘magnitude of disagreement’. This method is applied to derive a seamless thematic map of the land cover of eastern Ontario from two disparate map series. The importance of assessing data quality throughout the process using multiple reference data sets is highlighted, and limitations of the method are discussed. [ABSTRACT FROM PUBLISHER]

Abstract: This paper provides a literature review of articles on the primary forest fuel supply chain which have been published in English speaking peer-reviewed journals from 1989 to 2011. The focus is on the key issues of the transportation of primary forest fuel to heat and/or power plants: (i) transportation modes, (ii) terminal types, and (iii) forest fuel supply chain management, and provides basics on the logistically relevant characteristics of wood as feedstock such as on various feedstock assortments. The analysed supply chains include the transshipment, storage, handling (e.g. chipping) and transportation of primary forest fuel from the place of harvest to energy conversion plant. Due to spatial distribution, low mass density, low energy density and low bulk density, the transportation of primary forest fuel is crucial for economic efficiency as well as for reduced CO2 emissions. As a consequence of forests accessibility, road transportation (after hauling the biomass to the forest road) is the first step of the modern primary forest fuel supply chain. For longer transportation distances, rail or waterway is preferred because of lower transportation costs per volume transported and lower CO2 emissions. We highlight that some experience exists in multimodal transport, including truck, train or ship. Intermodal transport, however, has not been studied in the past and, therefore, an outlook for the research requirements is made here. [Copyright &y& Elsevier]

Lignocellulosic biomass represents a huge potential for energy production. However, it is relatively an unemployed source for biofuel and biogas production due to the difficulties obtained in the digestibility of the lignocellulosic materials and the inaccessibility of the polymers to the enzymes for degradation. The authors thus review some of the unconventional technologies that have been freshly developed (since a decade and a half) for lignocellulosic biomass pretreatment so as to break the lignin seal, liberate cellulose from the plant cell wall matrix, disrupt and reduce the crystallinity of the cellulose, increase the porosity of the biomass, and achieve desired fractionation. As a result, the cellulose will be rendered more accessible to enzymes for rapid and efficient hydrolysis and this will enhance biogas or biofuel production. The various components of lignocelluloses are initially described. The various technologies that exist for pretreatment of lignocellulosic materials are then classified into physical, physicochemical, chemical, and biological pretreatments. For physical pretreatment, microwave irradiation, ultrasound irradiation, and pulsed electric field are reviewed. For physicochemical pretreatment, ammonia fiber explosion, supercritical carbon dioxide explosion, and steam explosion are discussed. For chemical pretreatment, ammonia recycled percolation, organosolv process, and oxidative processes such as ozonolysis and wet oxidation are reviewed. Finally, biological pretreatment consists of microbial and enzymatic treatment. For each of these aforementioned technologies, the effects on biofuel and biogas production from different biomass are described and discussed with the aid of past studies. [ABSTRACT FROM PUBLISHER]

Abstract: Renewable energy will play a crucial role in the future society of the 21st century. The various renewable energy sources need to be balanced and their use carefully planned since they are characterized by high temporal and spatial variability that will pose challenges to maintaining a well balanced supply and to the stability of the grid. This article examines the ways that future ‘energy landscapes’ can be modelled in time and space. Biomass needs a great deal of space per unit of energy produced but it is an energy carrier that may be strategically useful in circumstances where other renewable energy carriers are likely to deliver less. A critical question considered in this article is whether a massive expansion in the use of biomass will allow us to construct future scenarios while repositioning the ‘energy landscape’ as an object of study. A second important issue is the utilization of heat from biomass energy plants. Biomass energy also has a larger spatial footprint than other carriers such as, for example, solar energy. This article seeks to provide a bridge between energy modelling and spatial planning while integrating research and techniques in energy modelling with Geographic Information Science. This encompasses GIS, remote sensing, spatial disaggregation techniques and geovisualization. Several case studies in Austria and Germany demonstrate a top-down methodology and some results while stepwise calculating potentials from theoretical to technically feasible potentials and setting the scene for the definition of economic potentials based on scenarios and assumptions. [Copyright &y& Elsevier]

Bioenergy makes up a significant portion of the global primary energy pie, and its production from modernized technology is foreseen to substantially increase. The climate neutrality of biogenic CO2 emissions from bioenergy grown from sustainably managed biomass resource pools has recently been questioned. The temporary change caused in atmospheric CO2 concentration from biogenic carbon fluxes was found to be largely dependent on the length of biomass rotation period. In this work, we also show the importance of accounting for the unutilized biomass that is left to decompose in the resource pool and how the characterization factor for the climate impact of biogenic CO2 emissions changes whether residues are removed for bioenergy or not. With the case of Norwegian Spruce biomass grown in Norway, we found that significantly more biogenic CO2 emissions should be accounted towards contributing to global warming potential when residues are left in the forest. For a 100-year time horizon, the global warming potential bio factors suggest that between 44 and 62% of carbon-flux, neutral biogenic CO2 emissions at the energy conversion plant should be attributed to causing equivalent climate change potential as fossil-based CO2 emissions. For a given forest residue extraction scenario, the same factor should be applied to the combustion of any combination of stem and forest residues. Life cycle analysis practitioners should take these impacts into account and similar region/species specific factors should be developed. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to explore the magnitude of Zimbabwe's biomass resources available for energy production using thermochemical conversion route. This involved estimation biomass from crops, forestry, livestock and Municipal Solid Residues (MSR). A model for estimating biomass energy potential was developed in Microsoft Excel. The crop and forestry production and livestock data used as a basis of calculations was obtained from FAOSTAT. The biomass residues available for energy production were calculated from residues produced considering economic and environmental concerns associated with the removal of crop residues from land and current residue uses. The energy content was obtained by multiplying the available biomass by specific biomass energy content. The total biomass energy was estimated at an annual average of 413.2 PJ but only 279.5 PJ (23.8% crops, 17.8% crop residues, 45.2% forestry resources, 12.2% livestock residue and 1.0% MSR) is sustainably available. Of this energy 189.3 PJ (26.3% from crop residue, 47.9% from woodfuel, 6.4% from forestry residue, 18.0% from livestock residue and 1.5% from MSR) can be used for energy production without competing for resources with food/feed production and other biomass applications. This can meet approximately 48% of the current energy consumption. [Copyright &y& Elsevier]

Abstract: Fast pyrolysis of biomass is becoming increasingly important in some member countries of the International Energy Agency (IEA). Six countries have joined the IEA Task 34 of the Bioenergy Activity: Canada, Finland, Germany, Netherlands, UK, and USA. The National Task Leaders give an overview of the current activities in their countries both on research, pilot and demonstration level. [Copyright &y& Elsevier]

Grassland biomass has been identified as a potential energy source. The combustion of mature and fibrous biomass, as occurs in extensive grasslands managed with low cutting frequencies, is one possible conversion technique. This study tested the relationship between plant diversity and biomass constituents relevant for combustion, as they determine energy content, energy yield and emission and corrosion risks. The biomass from a biodiversity experiment, with a species richness ( SR) gradient of 1-60 species from Central European mesophilic grasslands divided into four functional groups (grasses, legumes, small and tall herbs), was harvested twice a year (in 2008 and 2009). The higher heating value ( HHV) was estimated from carbon, hydrogen and oxygen contents to give insight into the energy potential of the species mixtures. The potential risk of emission and corrosion was assessed by analysing ash content, potassium, calcium, magnesium, nitrogen, sulphur and chloride content. HHV was independent of SR, and the overall mean was 18·13 MJ kg−1 DM. Biomass and gross energy ( GE) yield were positively affected by SR. The presence of legumes in a mixture resulted in increased HHV, biomass yield and GE, irrespective of the level of SR. Annual GE varied between 59 (average of monocultures) and 152 GJ ha−1 year−1 (mixture of sixty species). The concentration of ash-forming elements was generally high, suggesting a pre-treatment of the biomass prior to combustion. Emission- and corrosion-related constituents were clearly affected by the different functional groups, and sulphur and nitrogen both declined with SR. The results of this study show that high SR in experimental grassland communities is beneficial for the energy output and that legumes play a key role for the energy potential. However, identifying a functional group as being solely beneficial or disadvantageous for fuel quality was difficult. [ABSTRACT FROM AUTHOR]

Abstract: This study analyses the use of liquid, solid and gaseous biomass for power generation in Germany with respect to the Renewable Energy Sources Act (EEG), a significant policy instrument for promoting electricity generation based on renewable energy sources. The aim is the identification of bioenergy conversion pathways that have a low environmental impact and are cost-effective. To achieve this objective several research steps were undertaken, including a life-cycle analysis (LCA), economic analysis and the determination of the CO2 abatement costs. Besides, the authors show and discuss how a simplification of the environmental assessment by considering only the impact category greenhouse gases or the application of different calculation methodologies (i.e. allocation rules between electricity and heat produced) can affect the results. Overall the results show that the use of solid (wood) and gaseous biomass pathways causes both the lowest environmental impacts and electricity production costs when used for electricity generation. The choice of the modelling and calculation methodology may significantly influence the outcome (i.e. application of an exergetic allocation increases the environmental burden related to electricity generation). The lowest CO2-abatement costs were determined for the biodegradable waste pathway. [Copyright &y& Elsevier]

Abstract: Association of microalgae culture and anaerobic digestion seems a promising technology for sustainable algal biomass and biogas production. The use of digestates for sustaining the growth of microalgae reduces the costs and the environmental impacts associated with the substantial algal nutrient requirements. A natural marine algae–bacteria consortium was selected by growing on a medium containing macro nutrients (ammonia, phosphate and acetate) specific of a digestate, and was submitted to a factorial experimental design with different levels of temperature, light and pH. The microalgal consortium reached a maximum C conversion efficiency (i.e. ratio between carbon content produced and carbon supplied through light photosynthetic C conversion and acetate) of 3.6%. The presence of bacteria increased this maximum C conversion efficiency up to 6.3%. The associated bacterial community was considered beneficial to the total biomass production by recycling the carbon lost during photosynthesis and assimilating organic by-products from anaerobic digestion. [Copyright &y& Elsevier]

Abstract: Bioenergy schemes are multi-faceted and complex by nature, with many available raw material supplies and technical options and a diverse set of stakeholders holding a raft of conflicting opinions. To develop and operate a successful scheme there are many requirements that should be considered and satisfied. This paper provides a review of those academic works attempting to deal with problems arising within the bioenergy sector using multi-criteria decision-making (MCDM) methods. These methods are particularly suitable to bioenergy given its multi-faceted nature but could be equally relevant to other energy conversion technologies. Related articles appearing in the international journals from 2000 to 2010 are gathered and analysed so that the following two questions can be answered. (i) Which methods are the most popular? (ii) Which problems attract the most attention? The review finds that optimisation methods are most popular with methods choosing between few alternatives being used in 44% of reviewed papers and methods choosing between many alternatives being used in 28%. The most popular application area was to technology selection with 27% of reviewed papers followed by policy decisions with 18%. [Copyright &y& Elsevier]

Abstract: Bioenergy is one of the most dynamic and rapidly changing sectors of the global energy economy. The use of food crops for conversion to biofuel has been criticized for several reasons, among which its competition with the global food chain. Instead, lignocellulosic substrates are claimed to provide a bioenergy alternative without competing with food demand. This is particularly true when dealing with residues or waste. In this paper, we explored the environmental performance and sustainability of a bioenergy production system that integrates wastewater treatment, willow farming, and a Combined Heat and Power plant (CHP) located in Enköping (Sweden). Several methodologies for environmental assessment are integrated in this study within a life cycle perspective to investigate material and energy requirements as well as emissions and related impacts of the whole bioenergy production chain. Results show that full integration of different subsystems of a productive network is a desirable option for bioenergy production, within a zero emission oriented production pattern. The investigated wood biomass powered CHP plant was able to co-generate heat and electricity with high production efficiency and much better environmental performance and sustainability than fossil fuel based power plants. [Copyright &y& Elsevier]

Abstract: Green cut material is a potential source of renewable energy which is not fully exploited through conventional energy recovery systems. A new energy conversion process, the integrated generation of solid fuel and biogas from biomass (IFBB), which includes mechanical separation after hydro-thermal conditioning, was investigated. Ash softening temperature and lower heating value of the solid fuel were increased through the IFFB process in comparison to the untreated raw material. The net energy yield of IFBB at 40°C conditioning temperature ranged between 1.96 and 2.85kWhkg−1 dry matter (DM) and for the direct combustion between 1.75 and 2.65kWhkg−1 DM. Conversion efficiencies for the IFBB system were 0.42–0.68 and for direct combustion 0.42–0.63. The IFBB system produces storable energy from material which is nowadays not used for energy conversion. [Copyright &y& Elsevier]

Abstract: Within the state of Oregon, USA, there is considerable interest in the possibility of converting forest biomass to energy. A number of studies have assessed the technical feasibility of forest biomass energy, but few have focused on social aspects, an important consideration in projects involving public forests. This study explores the social context of converting forest biomass to energy, using qualitative research methods. Semi-structured interviews were conducted with forty individuals representing nine different stakeholder groups. Information gained through interviews was used to understand stakeholder views on forest biomass energy, including their perspectives on potential barriers and opportunities in Oregon. Findings indicate the most challenging barrier will be access to long-term, consistent supply. A related challenge is the long history of contention between parties over forest products coming from public lands. However, findings also show that there are many areas of common ground between these groups that have historically been at odds, such as agreement on the necessity of restoration treatments in certain forest types, the by-product of which could be used for biomass generation. Potential conflicts still exist, for instance over projects in mixed conifer forests. Development of policies and projects through inclusive, collaborative approaches could alleviate controversies, potentially allowing more activities to move forward. Information provided by this research creates a foundation for discussions as forest biomass energy becomes an increasingly prominent issue in Oregon, the western USA, and other regions of the world. [ABSTRACT FROM AUTHOR]

Modern bioenergy is commercial energy production from biomass for industry, power generation, or transport fuels. Bioenergy is an inclusive term for all forms of biomass and biofuels. Green energy is an alternate term for renewable energy that is the energy generated from sources that are considered environmentally friendly. The term biofuel is referred to as liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. Bioethanol is a petrol additive/substitute. It is possible that wood, straw, and even household wastes may be economically converted to bioethanol. Bioethanol is derived from alcoholic fermentation of sucrose or simple sugars, which are produced from biomass by hydrolysis process. Biodiesel is an environmentally friendly alternative liquid fuel that can be used in any diesel engine without modification. [ABSTRACT FROM AUTHOR]

Abstract: Bioenergy is regarded as cost-effective option to reduce CO2 emissions from fossil fuel combustion. Among newly developed biomass conversion technologies are biomass integrated gas combined cycle plants (BIGCC) as well as ethanol and methanol production based on woody biomass feedstock. Furthermore, bioenergy systems with carbon capture and storage (BECS) may allow negative CO2 emissions in the future. It is still not clear which woody biomass conversion technology reduces fossil CO2 emissions at least costs. This article presents a spatial explicit optimization model that assesses new biomass conversion technologies for fuel, heat and power production and compares them with woody pellets for heat production in Austria. The spatial distributions of biomass supply and energy demand have significant impact on the total supply costs of alternative bioenergy systems and are therefore included in the modeling process. Many model parameters that describe new bioenergy technologies are uncertain, because some of the technologies are not commercially developed yet. Monte-Carlo simulations are used to analyze model parameter uncertainty. Model results show that heat production with pellets is to be preferred over BIGCC at low carbon prices while BECS is cost-effective to reduce CO2 emissions at higher carbon prices. Fuel production – methanol as well as ethanol – reduces less CO2 emissions and is therefore less cost-effective in reducing CO2 emissions. [Copyright &y& Elsevier]

Abstract: Energy from biomass, bioenergy, is a perspective source to replace fossil fuels in the future, as it is abundant, clean, and carbon dioxide neutral. Biomass can be combusted directly to generate heat and electricity, and by means of thermo-chemical and bio-chemical processes it can be converted into bio-fuels in the forms of solid (e.g., charcoal), liquid (e.g., bio-oils, methanol and ethanol), and gas (e.g., methane and hydrogen), which can be used further for heat and power generation. This paper provides an overview of the principles, reactions, and applications of four fundamental thermo-chemical processes (combustion, pyrolysis, gasification, and liquefaction) for bioenergy production, as well as recent developments in these technologies. Some advanced thermo-chemical processes, including co-firing/co-combustion of biomass with coal or natural gas, fast pyrolysis, plasma gasification and supercritical water gasification, are introduced. The advantages and disadvantages, potential for future applications and challenges of these processes are discussed. The co-firing of biomass and coal is the easiest and most economical approach for the generation of bioenergy on a large-sale. Fast pyrolysis has attracted attention as it is to date the only industrially available technology for the production of bio-oils. Plasma techniques, due to their high destruction and reduction efficiencies for any form of waste, have great application potential for hazardous waste treatment. Supercritical water gasification is a promising approach for hydrogen generation from biomass feedstocks, especially those with high moisture contents. [Copyright &y& Elsevier]