Search

Canada's cellulosic ethanol biorefinery concept is supported by federal and provincial government legislative ethanol mandates as well as enabling science and innovation policies for technology development to support the economic and sustainable production of cellulosic ethanol and co-products from Canada's abundant supply of lignocellulosic agricultural and forestry biomass. In particular, the development of pretreatment, hydrolysis, and fermentation technologies is regarded as a critical integrating step for the commercialization of cellulosic ethanol biorefinery business concepts. These critical steps are necessitated by the chemical structure of lignocellulosic biomass comprising carbohydrate polymers and lignin which constrains the ability of enzymes to convert these polymers into fermentable sugars without expensive and highly capital intensive pretreatment processes. This paper reviews science and innovation efforts by Canadian researchers in finding solutions to these constraints, in particular the development of hydrolysis and fermentation technologies. This paper also highlights the role of multi-institutional science and innovation collaborative approaches for advancing Canada's cellulosic ethanol biorefinery concept further downstream. While highlighting Canada's scientific progress, this review also outlines technology commercialization lags between basic research and full scale commercialization of a Canadian cellulosic ethanol biorefinery concept. Although this paper focuses on the near-term goal of cellulosic ethanol production, it nevertheless recognizes that ethanol is only the first step in the longer-term goal aimed at a full integrated bioconversion of lignocellulosic biomass into biofuels and a wide range of value-added biochemicals and biomaterials, consistent with the cellulosic biorefinery concept. [ABSTRACT FROM AUTHOR]

In the last decade several scientific papers have dealt with the damages fossil fuels did to our environment. Carbon dioxide has been blamed the chief culprit since it is produced by the automobile fleet that uses diesel or gasoline as a fuel. As a result, several countries are implementing public policies aimed at the replacement of fossil fuels by renewable ones, such as biodiesel. Brazil has become one of them, since the biodiesel production has increased from 736 m 3 to 3,419,838 m 3 in less than ten years. Therefore, this paper intends to briefly review the literature on the history, evolution, and the environmental aspects of biodiesel in Brazil in order to show its positive economic impact on the Brazilian economy, in addition to showing how important this biofuel is to the environment by providing an overview of its advantages when compared to fossil diesel. [ABSTRACT FROM AUTHOR]

This paper first reviews the potential causality from biomass energy to CO 2 emissions and economic development within relevant literature. Later, the paper examines statistically the impacts of biomass energy consumption on CO 2 emissions and GDP in the US. To this end, paper observes environmental and economic implications of biomass fuel usage throughout energy literature and launches asymmetric causality test to confirm/disconfirm the literature output. The findings of the tests indicate that biomass energy consumption per capita mitigates CO 2 emissions per capita and increases GDP per capita. Eventually, upon its output, this research asserts that biomass energy consumption can be an efficient policy tool for environmentally sustainable development in the US, and, that, hence, biomass production technologies and biomass consumption need to be promoted in other countries as well as in the US. On the other hand, analyses underline the fact that policy makers should consider as well some potential constraints of biomass energy usage such as land use constraints and carbon leakage from biomass production. Therefore, although this paper explores the remedial impact of biomass on environment and growth, one may suggest also that further possible works consider the effects of biomass sources in detail to minimize the some worsening influence of biomass usage on climate change. [ABSTRACT FROM AUTHOR]

Synthesis gas, also known as syngas, produced from biomass materials has been identified as a potential source of renewable energy. Syngas is mainly consists of CO and H 2 , which can be used directly as fuel source for power generation and transport fuel, as well as feedstock for chemical production. Syngas is produced through biomass gasification process that converts solids to gas phase via thermochemical conversion reactions. This paper critically reviews the type of gasifiers that have been used for biomass gasification, including fixed bed, fluidized bed, entrained flow and transport reactor types. The advantages and limitations of these gasifiers are compared, followed by discussion on the key parameters that are critical for the optimum production of syngas. Depending on the biomass feedstock, the properties and characteristics of syngas produced can be varied. It is thus essential to thoroughly characterise the properties of biomass to understand the limitations in order to identify the suitable methods for gasification. This paper later focuses on a specific biomass – oil palm-based for syngas production in the context of Malaysia, where palm biomass is readily available in abundance. The properties and suitability for gasification of the major palm biomass, including empty fruit bunch, oil palm fronds and palm kernel shells are reviewed. Optimization of the gasification process can significantly improve the prospect of commercial syngas production. [ABSTRACT FROM AUTHOR]

Current global energy scenario and the environmental deterioration aspect motivates substituting fossil fuel with a renewable energy resource – especially transport fuel. This paper reviews the current status of trending biomass to liquid (BTL) conversion processes and focuses on the technological developments in Fischer Tropsch (FT) process. FT catalysts in use, and recent understanding of FT kinetics are explored. Liquid fuels produced via FT process from biomass derived syngas promises an attractive, clean, carbon-neutral and sustainable energy source for the transportation sector. Performance of the FT process with various catalysts, operating conditions and its influence on the FT products are also presented. Experience from large scale commercial installations of FT plants, primarily utilizing coal based gasifiers, are discussed. Though biomass gasification plants exist for power generation via gas engines with power output of about 2 MW e ; there are only a few equivalent sized FT plants for biomass derived syngas. This paper discusses the recent developments in conversion of biomass to liquid (BTL) transportation fuels via FT reaction and worldwide attempts to commercialize this process. All the data presented and analysed here have been consolidated from research experiences at laboratory scale as well as from industrial systems. Economic aspects of BTL are reviewed and compared. [ABSTRACT FROM AUTHOR]

Translating resource efficiency into practical European, national and local policy frameworks which integrate the various economic, social and environmental components passes through short to long term visions, strategies as well as measurable targets. The RE-SEEties project was funded by the South East Europe programme in order to contribute to the resource efficiency challenge. The project investigated on energy consumption and waste production and disposal; potential changes in consumption patterns and how policy making alternatives may support the achievement of resource efficiency targets. This paper aims to present the main results of this unique international cooperative experience carried out by research centres and municipalities in the South East Europe area. First, the paper focuses on the methodological toolkit and criteria for assessment which aims to support municipalities in creating a sustainable and resource efficient future through coherent and appropriate planning practices. Second, the paper discusses the main results obtained and lessons learned on a wide range of interrelated issues covering the policymaking process, financing of local resource-efficiency investments, good practices, tools to support decision-making and assessment methodologies. It also covers behavioural change and how policy can stimulate public authorities, companies and citizens to become more sustainable. [ABSTRACT FROM AUTHOR]

This paper provides a review of the artificial floating island (AFI) concept, structure, and functions. This review discusses the potential advantages of AFI technology for a variety of applications that include nutrition removal, biomass production, aquaculture and agriculture, as well as wastewater and stormwater treatment. The paper briefly discusses the role of a numerical model in the decision making process for choosing appropriate scale of AFI system for the sites to be treated. Besides suggesting potential future research prospects, this paper also raises certain drawback issues that AFIs may post to the environment. [ABSTRACT FROM AUTHOR]

This paper analyzes the capability of Reunion Island to achieve electricity autonomy by 2030. Currently, electricity production in Reunion Island is mainly based on imported fuels while it is blessed with high levels of renewable energy potentials. The issue addressed in this paper is the technical and economical feasibility of this ambitious target. The approach relies on a prospective study conducted by the TIMES-Reunion model which provides future production mixes according to different scenarios. It is combined with a quantitative assessment of reliability of power supply with two reliability indicators, regarding that intermittent sources may highly develop and consequently worsen reliability. This study enables us to draw three main conclusions: (i) electricity autonomy can be achieved thanks to high levels of biomass production and of intermittent sources; (ii) however, since fuel oil׳s power plants appear as back-up units, the reliability of power supply will be lowered. This is illustrated by the decrease of the reliability indicators over the time horizon; (iii) however, provided that appropriate rules on the instantaneous production are enforced, a generation mix that both complies with the electricity autonomy target and with a satisfying reliability of power supply is possible. [ABSTRACT FROM AUTHOR]

Recently, non-edible oil resources are gaining worldwide attention because they can be found easily in many parts of the world especially wastelands that are not appropriate for cultivating food crops, eliminate competition for food, more efficient, more environmentally friendly, produce useful by-products and they are more economical compared to edible oils. Jatropha curcas, Pongamia pinnata, Calophyllum inophyllum, Croton megalocarpus and Azadirachta indica are some of the major non-edible feedstocks for biodiesel production. This paper investigates the potential of Calophyllum inophyllum as a promising feedstock for biodiesel production. In this paper, several aspects such as physical and chemical properties of crude Calophyllum inophyllum oil and methyl ester, fatty acid composition, blending and engine performance and emissions of Calophyllum inophyllum methyl ester were studied. Overall, Calophyllum inophyllum appears to be an acceptable feedstock for future biodiesel production. [ABSTRACT FROM AUTHOR]

Abstract: Microalgae are considered as a promising biofuel resource to fix carbon dioxide (CO2) in the future. Modelling microalgae growth is an effective method of studying the performance of microalgae growth manifested by the parameters including light distribution, pigment dynamics, nitrogen uptake, growth rate, respiration rate, temperature dependence, and depth dependence, and helping to control the culture of microalgae in artificial bioreactors. In this paper, the models of microalgae growth in nitrogen-limited and light-limited culture system for estimating biomass productivity are investigated by comparing different expressions and coefficients used in several main models. The results show that there are some differences among the results of numerical modelling due to different expressions and coefficients. This paper will lay a foundation for the selective use of microalgae growth models for researchers. [Copyright &y& Elsevier]

Abstract: This paper assesses the learning potential of dedicated wood production systems to boost yields and reduce production costs. In particular, the paper analyses past trends and provides a future outlook of developments in dedicated wood production for three cases: eucalyptus production in Brazil, poplar production in Italy and willow production in Sweden. A main objective of this paper is to evaluate the extent to which experience curves can be devised for conventional woody plantation systems, and whether these can also be applied to short rotation cropping (SRC) production systems. For current average SRC production systems, Italian poplar shows the highest cost at 5.5 €GJ−1 followed by Swedish willow at 4.4 €GJ−1 and Brazilian eucalyptus is produced to the lowest costs at 2.8 €GJ−1. It was assessed to what extent production costs can be reduced per step in the production cycle and how this affects the minimum cost levels that can ultimately be achieved. Ultimate cost reduction could lead to delivered costs of 2.2 €GJ−1 for poplar, 1.9 €GJ−1 for willow and 1.9 €GJ−1 for eucalyptus on better quality lands. Based on historic cost data and production trends, experience curves were applied providing progress ratios for poplar in Italy and eucalyptus in Brazil. Brazilian eucalyptus production follows a steeper slope (63–73%) than poplar in Italy (71–78%). The extent to, and rate at, which cost reductions can occur within the next 20 years were evaluated by combining current costs, minimum cost levels and progress ratios with ranges in European and global biomass demand projections. This shows that, at the assumed growth rates for biomass production in Europe and for global production, minimum cost levels can be reached within the next two decades for all cases. [Copyright &y& Elsevier]

Abstract: Biomass is one of the major sources of renewable energy in the World. This paper aims at observing primary biomass energy supply in some EU countries within periods1971–2009 and 1982–2009. Following related two panel data sets for biomass in EU, this work employs linear models and nonlinear threshold autoregression (TAR) models to test linearity against nonlinearity and nonstationarity against stationarity. If nonlinearity is found, then, the next step is to search transition variable and threshold value of the panel data sets. This paper eventually has the purpose to reveal if EU countries converge in the production of biomass in a linear form or nonlinear form. Findings show that panel of Austria, Denmark, Finland, France and Portugal follows nonlinear process and reaches partial convergence in per million primary solid biomass energy supply. However, the involvement of Belgium, Greece, Norway, Poland and Sweden to the panel yields linearity and divergence. One may suggest policy makers of EU and/or OECD, upon conclusion of this paper, to revise their energy policies to stimulate both production and consumption of biomass energy source. [Copyright &y& Elsevier]

Abstract: Because of biodegradability and nontoxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification of triacylglycerols. From economic and social reasons, edible oils should be replaced by lower-cost and reliable feedstocks for biodiesel production such as non-edible plant oils. This paper reviews various methods for biodiesel production from common non-edible oils employing alcoholysis reactions. The aim of this paper is to present the possibilities of the use of non-edible oils into biodiesel production, to consider the various methods for treatment of non-edible oils and to emphasize the influence of the operating and reaction conditions on the process rate and the ester yield. The special attention is paid to the possibilities of optimization, kinetics and improvement of biodiesel production from non-edible oils. [Copyright &y& Elsevier]

Conservation and restoration are crucial to maintaining a wide range of functions and services in wetlands, but it is difficult to find a reasonable and resource-efficient management option without sacrificing ecological values. In the present paper, we analyse the variability and dynamics of the chemical composition and energy potential of biomass from reedbeds, floodplain meadows, coastal meadows and reed canary grass cultivation in extracted peatlands. We observed that the chemical characteristics that are crucial for bioenergy production vary by biomass origin and over time. The bioenergy potential depends on biomass production and on the conversion method. The results indicate that the energy potential ranges from 122 to 190 GJ/ha per year in semi-natural floodplain meadows in the boreal zone. About 160 GJ/ha per year can be obtained from natural reedbeds but only about 120 GJ/ha per year from cultivated extracted peatlands. Using methane conversion, we can obtain only about 50%, and using ethanol conversion we can obtain less than 20% of the total energy potential of the herbaceous biomass of floodplain meadows. Although long-term studies on homo- and heterogeneous biomass production are required, we conclude that the local biomass of natural, semi-natural and artificial wetlands could contribute significantly to sustainable development. • Bioenergy production is higher in natural vegetation than in cultivated wetlands. • Carex spp. and Filipendula ulmaria are alternatives for wetland restoration. • Chemical composition and methane potential differ by biomass origin and over time. • Floodplain meadows have the highest energy potential among boreal zone wetlands. • Biofuel yield is higher through methane than through ethanol conversion. [ABSTRACT FROM AUTHOR]

Abstract The cultivation of marginal lands for bioenergy production has recently become a topic of research interest for the agronomic and agricultural economy scientific communities. The growing availability of arable land in the Mediterranean regions, as a consequence of the decline of cereal cropping systems and grain legume, provides ample opportunities for performing successful feedstock production on unmanaged areas. This paper seeks to capture and analyze ongoing and emerging questions concerning bioenergy production on marginal lands in the Mediterranean area in a framework of sustainability indicators. A qualitative methodology was adopted to evaluate the effectiveness of eight critical issues that bio-energy developers, scholars and policymakers should consider in terms of agronomic, techno-economic and methodological practices for growing bioenergy feedstock. The issues investigated on selected case studies are: Greenhouse gas emissions; soil quality; land restoration and phytoremediation capacity; water use and efficiency; biodiversity; land use/cover changes; farmers' willingness and acceptance of new agro-system, and profitability of value chain. Starting from an in-depth analysis of the definition of marginal land from the perspective of ecosystem service cascade, we synthesize how these challenges are nowadays addressed and which are the key bottlenecks, trends and potential directions for guiding future research into bioenergy production in the Mediterranean regions. The findings of this study suggest that dedicated energy crops can be grown on marginal lands with substantial positive effects in terms of sustainability aspects, although more efforts should be carried out through agronomic research especially on water use efficiency and biodiversity conservation, as well as by national and EU institutions and policies for promoting economic opportunities and integration with surrounding agro-ecosystems and farmers' involvement. Developing a site-specific landscape design with the use of Life Cycle Assessment and certification schemes with sustainability indicators is of primary importance for the effective bioenergy production on marginal lands. Graphical abstract fx1 Highlights • Key issues concerning bioenergy production in the Mediterranean area were analyzed. • The concept of marginal land was analyzed. • The use of tailored GBEP sustainability indicators was fostered. • Eight critical issues were reviewed discussing key results and future challenges. • Possible technical and policies improvement solutions are proposed. [ABSTRACT FROM AUTHOR]

Abstract Microalgae have been widely considered as the potential sources for bio-fuel production without affecting the environment. Hydrothermal liquefaction (HTL) is a suitable technology for converting high water-containing feedstocks (e.g., microalgae) to liquid fuel. However, the structural diversity and rigidity of the microalgal cell wall remains as the major techno-economic bottlenecks for the recovery of intramolecular compounds (e.g., lipid) from microalgae. In this paper, the recent developments in cell disruption technologies and HTL for various microalgae strains are reviewed. The available literature investigating the effect of microalgal pre-treatment on the production of microalgae-derived bio-crude oil are presented. Furthermore, this article provides an extensive review of the recent studies on the HTL of microalgae, including the influences of feedstock characteristics and various operating conditions, underlying reaction mechanism, and physicochemical properties of liquefaction products. Highlights • Recent developments in cell disruption for microalgae are reviewed. • Effect of pre-treatment on oil formation are presented. • HTL operating conditions and reaction pathways for microalgae are discussed. • Physical and chemical properties of HTL products from microalgae are covered. • Challenges and future directions are outlined. [ABSTRACT FROM AUTHOR]

Abstract Studies of the production and use of biomass of perennial plants as energy feedstock have been conducted by Polish researchers for over 20 years. One genus of particular interest is Salix spp. L., which occurs naturally in the temperate zone. Experiments concerning the productivity of willow have been conducted mainly on small-scale experimental fields, but there have been studies conducted on large-scale, experimental and commercial plantations. An analysis of the scientific literature found that the mean willow biomass yield was 8.5 Mg ha−1 y−1 d.m. The mean productivity on small-scale experimental fields (11.4 Mg ha−1 y−1 d.m.) was much higher than on large-scale fields (5.7 Mg ha−1 y−1 d.m.), by 4.5, 7.2 and 7.5 Mg ha−1 y−1 d.m. for biennial, triennial and quadrennial harvest cycles, respectively. Meanwhile, when the optimum yield-generating agents were applied (such as cultivar/clone, fertilisation rate or planting density) higher yields were achieved (by 48% and 72%) in small and large-scale experiments, respectively. Considering only the harvest cycle, the highest mean productivity was achieved in the longer cycles, triennial for small-scale experiments and biennial and triennial for large-scale experimental and commercial plantations. Studies conducted using small-scale experiments still play a very important role in the initial phase of studies on the yield-generating factors under analysis and enable their verification in multiple combinations. Meanwhile, farmers and researchers, as well as national policy-making institutions, value data from commercial plantations. However, there have been few papers published so far on the productivity of such plantations in Poland, particularly those describing studies conducted in similar soil conditions in successive harvest cycles. Moreover, studies should be conducted at sites with poor quality soil, i.e. intended for growing energy crops, where the yield is usually smaller than on good soils used in agriculture for the production of food and fodders. Graphical abstract fx1 Highlights • Studies of the productivity of willow were conducted in Poland for over 20 years. • Various clones and cultivars were tested in 1-, 2-, 3-, 4- and 5-year cycles. • The mean yield of willow in small-scale experiments was 11.4 ± 6.0 Mg ha−1 y−1 d.m. • The highest yield was achieved in 3-year harvest cycles. • The mean yield in large-scale experiments was smaller by 50% than in small-scale. [ABSTRACT FROM AUTHOR]

Abstract With their fast growth rate and ability to accumulate a high percentage of their weight as lipid and carbohydrate, microalgae potentially represent an ideal feedstock for the production of biodiesel and bioethanol. In addition, microalgae offer several environmental benefits, and do not compete with food production for land, fresh water, and nutrients. Therefore, the main goal of this work is to provide a quantitative, systematic and harmonized assessment of current bio-energy potential. The analysis is conducted by considering all the main steps in detail, from cultivation to biodiesel production, and by deriving an overall estimation of energy consumption for biodiesel production. Energy consumption uncertainty is also quantified and discussed. A systematic review of all the main technologies available for all the main processing steps towards the production of biodiesel from microalgae is presented, focusing on the derivation of the Net Energy Ratio (NER) of each combination of technologies, complemented by an uncertainty analysis of the data used and those obtained in the present work. A wide scatter in the data available in the literature has been identified, highlighting the need for an uncertainty analysis. If the average overall energy consumption per unit of biodiesel mass is considered, all the routes adopting a raceway pond have a lower energy consumption, but if the uncertainty on the overall energy consumption is also considered, the minimum value of the range of NER values for some of the routes adopting a photobioreactor is comparable to the NER value obtainable by using raceway ponds. Thus, the present framework proposes a harmonized and comprehensive methodology to compare and contrast technologies for the production of biodiesel from microalgae, and is applied in this paper to identify, with an appreciation of the uncertainty, the most promising combinations of technologies. Highlights • Quantitative, systematic and harmonized assessment of microalgae energy potential. • A step-by-step analysis and overall estimation of energy consumption is given. • A substantial uncertainty on the data in literature has been identified. • The energy consumption uncertainty is quantified and critically discussed. • Derivation of the Net Energy Ratio (NER) for each combination of technologies. [ABSTRACT FROM AUTHOR]

Abstract: There is an increasing interest in the production of chemicals and fuels from renewable resources due to the continuing price increase of fossil resources, the insecurity of the availability of fossil resources in the future, and additionally environmental concerns and legislations. Biobutanol may be produced by the acetone–butanol–ethanol (ABE) fermentation. This paper reviews the biobutanol production bringing up the problems and challenges to overcome. The aim of the paper is to help in finding opportunities to make the process feasible in the near future. The analysis stresses the idea of improving the efficiency of the fermentation stage by altering the up (pretreatment of the raw material) and downstream (product recovery and purification) processes. The paper also explores the biobutanol production from the biorefinery perspective. Finally the review brings up the important role of research in developing and implementing the production of biobutanol by the ABE fermentation. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with modelling the development of plantations for intentional biomass production. The model of plots for the areas of interest consider the following biomass sources: intentionally produced biomass from SRC of fast-growing trees and non-woody energy crops (sorrel, reed grass and triticale). Statistical data for the entire area of interest (NUTS1 size) and data for a part of this area (NUTS3 size—18% of total area of interest) were used to determine data on the area of arable land and permanent grasslands in the initial year. This paper presents a model of the development of production plots for the period 2008–2030. Yields are calculated of selected energy crops with regard to their growing cycle using so-called triangular method. The core of the algorithm for calculation of growing area of energy crop is an optimalization of processes regarding economic and technical demands for long-term and sustainable production of biomass. [Copyright &y& Elsevier]

Abstract: This paper presents a study based on the Systems Thinking and Scenario Planning (STSP) method, focusing the biodiesel production chain of Rio Grande do Sul State. The aim of the study was to identify key elements to comprehend the systemic structure of interaction among the ties of this chain. The study was held by a team of specialists over five months, including 15 meetings. Discussions were based on quantitative and qualitative data and a systemic map was constructed and refined. Based on this modeling, four different prospective scenarios were comparatively analyzed in order to propose strategic actions to promote the sustainability and competitiveness of the chain. The results were then presented to two different groups of external specialists in order to validate the conclusions drawn and the proposals. Both groups agreed with the ideas presented. The paper is constructed as follows: a brief introduction focusing on contextual elements of the biodiesel production in Brazil and in Rio Grande do Sul; some background material regarding agroindustrial production chains and an overview of the biodiesel production chain of interest; a description of the method used to perform the research; main results and discussion; and conclusions. With this paper the authors also hope to contribute to the discussion regarding competitiveness and sustainability of biofuel chains in Brazil. [Copyright &y& Elsevier]

This paper analyzes the long-run relationship between biomass energy production and biomass energy consumption in the United States (US), over 1993M01-2022M08. For robustness reasons, it is employed the cointegration methodology to sustain the main findings in parallel with unit root tests of biomass energy surplus/deficit. The main results evidence a long-run equilibrium between biomass energy production and biomass energy consumption in the US conditioned by structural breaks. More precisely, those breaks can severally alter biomass energy sustainability, their importance being crucial in the US's policy design in the biomass sector. Policymakers in the US should take into account the structural changes for their adjustments in the biomass energy market when no long-run equilibrium between biomass energy production and the biomass energy consumption is evidenced. Otherwise, no policy corrections are needed as the long-run equilibrium is reached based on the market self-regulation mechanism. • Biomass energy is sustainable in the US. • Biomass energy sustainability is conditioned by structural changes. • No hysteresis is observed in biomass energy surplus/deficit. • Market of biomass energy has a self-regulation mechanism under sustainability assumption. [ABSTRACT FROM AUTHOR]

Given both the ongoing expansion of world population and development of climate change conditions, it is increasingly imperative to develop and deploy sustainable biomass production methods to allow establishment of a flourishing and sustainable bioeconomy. Green technologies, including biofuels and bioproducts, are among the most effective strategies for decreasing greenhouse gas emissions and global warming, while meeting humanity's energy requirements. Biomass now provides a measure of energy to many countries, however supporting technologies are not widely accepted, largely because of low returns for biomass producers. This paper provides an overview of world biomass production and utilization. It also indicates potential approaches for enhancing biomass production: agronomic practices, associated microorganisms, genome editing, selection of optimal technologies, best combination approaches for feeding global human and animal populations, while, decreasing greenhouse gas emissions and replacing demand for fossil energy with bioenergy. A more novel concept is proposed, microbe-to-plant signal compounds, as the potential approach to address the challenges we are facing. These compounds (e.g., lipo-chitooligosaccharide and thuricin 17) have been shown to increase growth for diverse plant species, particularly when they are growing under stressful conditions, however, their commercial development/utilization is far from complete. This review paper will expand the understanding of using the signal interaction between crop and beneficial microorganisms not only to enhance plant growth but also promote agricultural sustainability and a stronger bioeconomy. • We must address the challenges of sustainable energy supply in the face of climate change and increased population. • By better understanding their biology and economics, biofuels and associated high-value bioproducts will be key to this. • A comprehensive overview of world biomass production and utilization is provided. • Enhanced biomass production through management of associated microorganisms, genetics and management are considered. • Microbe-to-plant signal compounds can contribute to climate change resilient agriculture. Then, this paper ends with a discussion of challenges and obstacles to promoting the application of advanced technologies and what is needed to overcome these. Establish the long-term benefits and value of biomass and the bioeconomy will also be discussed. [ABSTRACT FROM AUTHOR]

Hydrogen applicability in the power, chemical and petrochemical industries is constantly growing. Efficient methods of hydrogen generation from renewable sources, including waste products, are currently being developed, even though hydrogen is mainly produced through steam reforming or thermal cracking of natural gas or petroleum fractions. In paper alternative methods of hydrogen production with a particular emphasis on dark fermentation are discussed. The review compiles essential information on strains of bacteria used in the production of hydrogen from waste products in the agroindustry and from lignocellulosic biomass. The effect of such parameters as kind of raw material, method of processing, temperature, pH, substrate concentration, partial pressure of hydrogen, hydraulic retention time, method of inoculum preparation and the type and operating parameters of a reactor on the yield of dark fermentation is discussed. The review aims at presentation of current state of knowledge on the dark fermentation process utilizing waste materials as substrates. The results of investigations with emphasis on the most important issues regarding operating parameters of dark fermentation are also included. [ABSTRACT FROM AUTHOR]

Biogas generation from vinasse, a problematic residue from the ethanol process, has been discussed as an alternative to increase sustainability and profitability in the Brazilian sugarcane industry. Recent studies have widely assessed the technical feasibility of biogas projects. However, the economic impact of this new product on the overall results of sugarcane mills still needs to be addressed, as this is still an incipient technology in the sector. As price risks represent a significant issue for production decisions in the sugarcane industry, and they may be addressed through portfolio diversification, this paper aims to examine the implications of the insertion of biogas into their product portfolios. A risk measure broadly used in literature, CVaR, was applied in the optimization model proposed. Additionally, a robust counterpart for the model was developed to deal with price uncertainties and assess their potential impact on the portfolio decisions. The models were validated through both a ceteris paribus and a factorial analysis, and the results obtained allowed the understanding of the role that biogas production may play in the sugarcane industry. In both models, standard and robust, the use of biogas for the substitution of diesel stands out as the only economic application. The results also indicate that, for most of the price scenarios performed, electricity generation from biogas is not economically feasible. Furthermore, it was highlighted that the insertion of biogas into the portfolio yields a gain in the overall efficient frontier of sugarcane mills. Thus, in conclusion, this study presents strong evidence of the economic feasibility of biogas generation in the Brazilian sugarcane industry and the model developed to perform this analysis is shown to be a powerful tool to further assess the impact of price policies on their production decisions. [ABSTRACT FROM AUTHOR]

Environmental, economic and political pressures have driven the interest towards the search of sustainable feedstock for biofuel production. At present, macroalgae (green, brown and red marine seaweed) is getting growing consideration as an alternative resource for sustainable biomass to produce biofuels, biochemical and food. The unique chemical composition and wide variation in the availability create various opportunities and also challenges for bio-based energy production. Recently, numerous studies have taken place in the exploitation of seaweed as carbon sources for the bioethanol production. Thus, this paper attempts to highlight the characteristics, processing techniques and potential applications of the seaweed. The present review also focuses on recent innovative approaches for the sustainable production of bioenergy from seaweed. [ABSTRACT FROM AUTHOR]

Starting from the assumption that household energy use is manifold and intertwined, shaped by many factors which overlap not only at the individual level, but also at a higher level of scales, the paper developed a more integrated approach to its determinants. To assess them and also to find out whether there is a difference between regional-level factors that determine it universally, and those that are context-dependent, the static and dynamic panel analyses were employed in 64 European regions over the period from 2005 to 2013. Our findings suggest that there are common energy consumption determinants and those ones that are dependent on the regions’ level of development. While the sign of the impact of the former is the same across regions, the impact of the latter may differ, depending on the character of the energy policy measures applied. Findings also suggest that energy policy authorities have opportunities to develop and encourage energy efficiency and sustainable use of energy of the household sector by creating regional-specific demand-side energy efficiency programs and measures as well as user practices in relation to technology. [ABSTRACT FROM AUTHOR]

In recent years, biodiesel production has grabbed significant attention due to the awareness of fossil fuel exhaustion. Microalgae become interested feedstock candidate of biodiesel production as they have rapid growth rate and high oil content compared to crops. Efforts have been made to increase microalgae productivity and oil content. To investigate the potential of microalgae for biodiesel production, it is essential to knowledge if the microalgae oil is qualified as possible feedstock oil. Moreover, what would be the energy and environmental effect of the production? And whether the production cost would be reasonable? This paper compared the properties of microalgae oil with traditional biodiesel production oils (vegetable oils); the properties of the biodiesel produced from microalgae and vegetable oils; reviewed the net energy ratio (energy output to energy input), GHG emissions, and economic analysis of the process of biodiesel production from microalgae; as well as discussed the factors which would influent the energy, environment, and cost of the process. [ABSTRACT FROM AUTHOR]

The supply of nutrients is a great issue to a sustainable scale-up of microalgal biofuels production, as these photosynthetic microorganisms require large amounts of N, P and other micronutrients to grow, which turns into high fertilizers demand. Additionally, recovery and reuse of nutrients (particularly N & P) are a must to reduce the non-point pollution emanating from their release into water or air during the downstream processing steps to biofuels or bioproducts. In the recent years, strong research efforts have been paid for developing nutrient recovery and recycling techniques, in order to reduce the net amount of fertilizers required. One possibility is exploiting nutrients from waste streams, such as wastewaters, while others focus on the recovery of N and P from the non-fuel fraction of the produced microalgal biomass, which is then recycled to the cultivation system, in a closed-loop perspective. In both cases, the presence of possible contaminants as well as nutrients bioavailability can impact the biomass productivity compared to standard synthetic media. Although the nutrients recovery and reuse has been in the forefront for a few years, there are no review publications available yet. In this paper, state-of-the art studies on nutrients recovery and recycling methods in microalgae processing from the last decade are reviewed. The study focuses on the different N and P recovery methods and yields, as well as on their subsequent use in algal cultivation and impact on algae productivity. Possible bioproducts exploitation is considered, and perspectives of closed-loop material balances on a large-scale are eventually provided. [ABSTRACT FROM AUTHOR]

In this paper, a detailed review on the recent advances in the production of biofuels and biochemicals from microalgae and Jatropha is presented. This review includes critical elements of the sustainability of microalgae and Jatropha biorefineries such as technical analysis, socioeconomic considerations, and environmental impact assessments that are reported in recent studies. The integration of microalgae and Jatropha as viable feedstock for the production of biofuels and biochemicals which may serve as sustainable alternatives to fossils fuels and petrochemicals is also modeled using SuperPro designer. A technoeconomic assessment of the integrated biorefinery is carried out. United Arab Emirates (UAE) is considered as a geographical reference for the technoeconomic assessment. Three scenarios are examined. All scenarios involve the production of biodiesel and glycerol. In addition to these two products, the production of animal feed, organic fertilizer and biogas is considered in scenario 1. In scenario 2, the biorefinery products include bioethanol, organic fertilizer and biogas. Scenario 3 involves the production of hydrogen and animal feed. Scenario 1 is the base case, with which other scenarios are compared. Scenario 1 is profitable but scenarios 2 and 3 are not profitable. In addition, emissions from scenario 2 make it less attractive when it is compared to other scenarios. The integrated biorefinery with microalgae and Jatropha as feedstock is technically feasible and economically profitable in scenario 1, as modeled. [ABSTRACT FROM AUTHOR]

The objective of this paper is to review policies around the world that promote the conversion of food waste to biogas. We review policies and operational projects from a diverse set of case study countries including South Korea, China, France, Germany, and the United Kingdom. Using a four-step analysis methodology that focuses on each country's (1) food waste background, (2) food-waste-to-biogas policy environment, (3) status quo of food waste-to-biogas projects and (4) future policy/project-level challenges, we provide a comprehensive cross-country review of food waste-to-biogas policy developments. We find that, while each surveyed country has unique strengths and weaknesses in their policy structure, Asian and European countries also do face similar bottlenecks in the food waste-to-biogas sector. Some specific findings include: (1) highly centralized policies in Asian case countries such as China and South Korea have led to the rapid build-up of a food waste-to-biogas sector; (2) European case countries such as France and the United Kingdom have succeeded in implementing policies that incentivize the production of multiple outputs within treatment facilities; (3) South Korea is a good example of how countries can implement smart waste management systems to decrease the volume of FW generated at the source; (4) South Korea, Germany and France have successfully built many co-digestion projects treating FW together with other waste sources, indicating that project operators in countries have understood the multiple benefits of co-digestion. The geographic breadth of the case studies, and the best practices and challenges identified for each country, should prove highly useful for policy-makers in developing countries who are seeking to enhance food waste management via anaerobic treatment methods. [ABSTRACT FROM AUTHOR]

Due to depleting petroleum reserves and the environmental impact of fossil fuels, it is important to find alternative sources for transport fuels. An alternative solution is bio-alcohol fuel, which has potential in the transport sector and in electricity generation. Biomass-based sources offer the best solution for transitioning to liquid fuel because of its global availability and energetic gain. Current fuel research and development addresses process engineering trends for improving bio-alcohol production in pyrolysis. This paper addresses developments in modeling simulation, optimization and control systems related to bio-alcohol production. The most promising solutions to bio-alcohol fuel production costs by the generation of valuable co-products are analyzed. These findings are supported by heat and mass transfer in the production of bio-alcohol fuel as well as by economic analysis. Finally, some concluding considerations on current and future research trends in the study of bio-alcohol are presented. [ABSTRACT FROM AUTHOR]

Bio-oil production is a promising way to solve both energy shortage and agricultural waste pollution problems, while better upgrading methods of bio-oil are needed to enhance the economic efficiency. For this reason, hydrogen generation from biomass derived acetic acid, one of the major components in bio-oil, has been extensively researched. So far, a number of catalysts have been developed towards acetic acid steam reforming (AASR), but insightful review in this field is rarely seen. This paper is a critical review on current researching status about catalysts towards AASR, which includes catalyst development, mechanic understanding and catalyst deactivation. Meanwhile, the discussion for further researching directions and competitions are also presented. [ABSTRACT FROM AUTHOR]

The suspended microalgal cultivation systems targeting the production of lipid for biodiesel is still unable to meet the commercial and economic feasibility due to high energy and cost inputs during the harvesting process. Currently, the attached microalgal cultivation systems are known as an innovative technology to resolve the problematic aspects of suspended cultivation as the biomass can be easily separated from the culture medium with negligible energy input and no chemical need. Accordingly, this paper is focusing on reviewing various support materials utilized by researchers in growing the attached microalgal biomass in either fixed bed or fluidized bed bioreactor to ensure sustainable biomass production prior for biodiesel. An extensive review of the cultivation conditions impacting the growth of attached microalgal biomass is conducted in determining the optimized condition to enhance biomass productivity. The novelty of this paper is presented through in-depth analyses and discussions concerning the kinetic models and mechanisms study in selecting the suitable support materials for attached microalgal growth system. The incorporation of the cultivation condition parameter in predicting the growth of attached microalgae biomass via kinetic study is crucial in proffering new directions for technological developments and microalgal industry application. The ability of attached microalgal biomass in efficiently assimilate the nutrients available in the nutrient-rich wastewater for the microalgae growth is considered as an economical feasible approached. The suitable photobioreactor designs for growing the attached microalgal biomass are also discussed in detail in ensuring the sustainability of attached microalgal biomass production. Image 1 • Attached cultivation to ease microalgal biomass harvest for biodiesel production. • Microalgae cells attachment mechanism onto the support material. • Kinetic model to predict the growth of attached microalgal biomass. • Nutrient-rich wastewater treatment via assimilation by attached microalgal biomass. • Type of photobioreactors to promote the growth of attached microalgal biomass. [ABSTRACT FROM AUTHOR]

Economic and environmental developments in the last decades call for the displacement of fossil fuels to alternative energy sources. Biofuels are considered as a part of the solution for this challenge. Sustainable raw materials for the production of transportation biofuels such as biodiesel, biobutanol and bioethanol, can be obtained from algal biomass. In particular, marine macroalgal biomass is a promising feedstock for transportation biofuels because of (the) its fast growth and its potential cultivation on seawater, avoiding competition of resources with conventional agriculture of terrestrial plants used for food. In addition, dissolved inorganic nutrients like nitrogen, phosphorous and carbon are taken up by macroalgae, helping to alleviate eutrophication in seas and oceans. Using biological, chemical and engineering advances in the last decades, technologies to provide cost efficient cultivation, harvesting, extraction and processing of sustainable biofuels have to be elaborated. This paper provides a review of macroalgae based biorefineries with offshore cultivation and consequent biomass conversion into transportation liquid biofuels. We discuss the methods for offshore cultivation, harvesting, and conversion of macroalgae biomass into liquid transportation biofuels. Based on the current information and global experience, we present local perspectives specific for France, Germany, Norway, the Netherlands and Israel on the potential use of Exclusive Economic Zone for transportation biofuels production. Marketable suggestions for future research need to include all stakeholders of a given site for offshore biorefinery development. [ABSTRACT FROM AUTHOR]

This paper reviews European land and bioenergy potential studies to 1) identify shortcomings related to how they account for agricultural intensification and its associated environmental effects, and sustainability constraints, and 2) provide suggestions on how these shortcomings can be improved in future assessments. The key shortcomings are: The environmental impacts of intensification are nearly always ignored in the reviewed studies, while these impacts should be accounted for if intensification is required to make land available for energy cropping. Future productivity developments of crops and livestock, and the associated land-use and environmental effects are currently limited to conventional intensification measures whereby the proportion between inputs and outputs is fixed. Sustainable intensification measures, which increase land productivity with similar or lower inputs, are ignored in the reviewed studies. Livestock productivity developments, livestock specific intensification measures and their environmental effects are poorly or not at all covered in the reviewed studies. Most studies neglect sustainability constraints other than GHG emissions in the selection of energy crops. This includes limitations to rainfed energy crop cultivation, a minimum number of crop species, the structural diversity within cropping areas and the integration of energy crops in existing or new crop rotations, while simultaneously considering the effects on subsequent crops. These shortcomings suggest that the identification of sustainable pathways for European bioenergy production requires a more integrative approach combining land demand for food, feed and energy crop production, including different intensification pathways, and the consequent direct and indirect environmental impacts. A better inclusion of management practices into such approach will improve the assessment of intensification, its environmental consequences and the sustainable bioenergy potential from agricultural feedstocks. [ABSTRACT FROM AUTHOR]

The paper focuses on the design of a methodology that links the modelling of biomass potential from agricultural land using geographic information systems (derivation of biomass yields according to soil, topographical and climatic characteristics) with the growing need to provide non-productive functions contributing to sustainable land use and ensure the economic viability of biomass from energy crops. According to the proposed methodology, perennial energy crops are prioritized for allocation where the land risk index is highest. The land risk index is determined by assessing 5 basic characteristics - landscape connectivity, landscape heterogeneity, threat of drought, threat of water erosion and threat of soil erosion. In order to assess the economic competitiveness of biomass produced, a methodology for determining biomass production price is used, with the aim of matching the economic effect of growing conventional crops. Land best allocated to perennial energy crops is characterized by a high land risk index value and a competitive biomass production price. The application of the methodology is demonstrated using the case study of the Czech Republic. The results of the case study show that when energy crops are selected based on a combination of necessary non-productive functions and economic competitiveness, this significantly influences the allocation of perennial energy crops to individual land blocks and their contribution to biomass energy potential. [Display omitted] • Perennial energy crops can reduce risks associated with intensive land management. • Regional differences exist in the ecological risks associated with intensive agriculture. • Prioritization of non-productive functions of perennial crops significantly affects biomass potential. • High profitability of conventional crops often blocks the allocation of energy crops. [ABSTRACT FROM AUTHOR]

The overview of developed so far methods for biometric measurements showed a lack of application of the uniform standards, confirmed by the appropriate statistical tools. As a consequence, biomass’ productivity models built on their basis are incomparable between each other, and their use is limited. The paper presents an innovative method of probabilistic description of biometric features of basket willow ( Salix viminalis ). It concerns the descriptive statistics regarding the characteristics of that plant with which it is possible to relate the diameter and length of the shoots of basket willow with its mass, introducing the concept of shoot volume index. For this purpose the results of biometric measurements, consisting in cutting randomly selected shoots in the period of vegetation and measuring their length, diameter in the middle of the length and their mass, were used. The measurements were conducted in 2011–2013, a period covering the second, third, and fourth years of extensive cultivation of basket willow. Those years were evidently distinctive as regards the weather (thermal and water) conditions. Two features of basket willow shoots were suggested for analysis: their volume index and their mass. They are statistically correctly described by a mixture of two gamma distributions, independent of plantation age and of the moment when the measurement was conducted in the period of vegetation. The number of shoots in a bush was described by shifted Pascal distribution. In each year of cultivation, this distribution statistically correctly described their number. [ABSTRACT FROM AUTHOR]

This paper presents a review on microalga Botryococcus braunii ( B. braunii ) with an emphasis on lipid production for possible industrial commercialization in biodiesel production. Summarizing the nature of this alga is fundamental to establish the detail environment conditions for optimal biomass growth and the production of lipids, as well as upstream processing technologies for biodiesel production. This study focuses the attention on identifying possible avenues for further investigation in the design of cultivation systems and the integration of process technologies at industrial scales. The advantages and disadvantages of biodiesel production processes based on these algal lipids are also analyzed. A particularly promising process involving B. braunii combines flue gas and wastewaters to produce lipids, converting them to biodiesel by supercritical (SC) direct trans/esterification (esterification followed by transesterification). We conclude that such processes using B. braunii have considerable potential for the production of cleaner and more efficient biodiesel than current methods, reducing the environmental impact of fossil fuel use. [ABSTRACT FROM AUTHOR]

Biomass gasification converts into syngas, then into other chemicals via Fischer-Tropsch (F-T) synthesis is promising for renewable energy utilization. Although gasification is a sustainable and environmental-friendly technology for value-added utilization of biomass, tar formation is the major problem during the biomass gasification. Tar could condense on the reactor then block and foul equipment. An optimized gasifier and highly active catalyst were proved to be effective for biomass tar elimination. Furthermore, tar formation mechanism and the decomposition pathway were also important to advance the optimization of gasification reactors and catalyst design. This paper summarized the fundamentals, such as gasifier types, Ni-based catalyst, and reaction and deactivation mechanism. This review also sheds light on other excellent catalysts, effective gasifiers and mathematical models of biomass catalytic gasification, and catalyst reaction mechanisms and mathematical models are also discussed in detail. At last, the paper ends with a conclusion and prospective discussion to the latter lab and industrial-scale research. • It sheds light on excellent catalysts, gasifiers of biomass gasification. • In-depth discussion of mathematical models are provided. • Detailed description of deactivation and reaction mechanisms. • Prospects and disadvantages of gasification reactions are described. [ABSTRACT FROM AUTHOR]

Electricity generation for rural applications through biomethanation process is very promising in countries like India where availability of biomass feedstock is very high. However, sustainability of biomass power plants requires meticulous planning starting from assessment of feedstock availability to collection, storage, transport and conversion in power plant. All these parameters are spatially inter-linked and therefore use of spatial tools such as GIS is helpful in such planning. This paper investigates electrical power generation potential of a newly constructed biomethanation plant in Sonitpur district of Assam, India. Spatial availability of locally available biomass feedstocks for methane generation is assessed using GIS. The GIS is also used for optimal biomass collection and transportation network design. Altogether, 7 different types of biomass feedstock (kitchen waste, vegetable waste, cow dung, pig droppings, goat droppings, poultry droppings and rice straw) are identified in the surrounding villages of the plant within optimum biomass supply radius. Biomass feedstock of the area can produce 37,000 m 3 methane; sufficient for continuous generation of 5.3 MW electricity. Power supply from the proposed plant would improve rural living standard and key areas such as education and health will be particularly benefited. However, biomass assessment and supply logistics would require managerial attention to minimize cost of power generation. [ABSTRACT FROM AUTHOR]

This paper reviews and assesses conditions for increased and efficient use of biomass in Central America (CA), providing an overview of conditions for biomass supply in each country. Then, a Fuzzy Multi-Actor Multi-Criteria Decision-Making (MCDM) method is applied to identify a portfolio of biomass conversion technologies appropriate for CA, considering technical, economic, environmental and socio-political aspects. The work is motivated by the relatively large availability of biomass in CA at the same time as current conversion of biomass is carried out in inefficient processes. The assessment of technologies includes thermochemical processes (pyrolysis, combustion and gasification) for production of different energy carriers, including improved cooking stoves (ICSs). The most promising biomass feedstocks in the region are residue based; animal (manure), forest and agricultural origin. We show that around 250 PJ/year could be available for the energy sector, which is equivalent to 34% of primary energy supply for CA. It is concluded that in the short term promoting and implementing ICSs will give the largest improvement in the efficiency of biomass use, whereas on the long term small combustion plants seem to be the best choice for transforming CA׳s biomass into a clean and sustainable energy carriers, boosting economy and industrial development. Results show that the introduction of ICSs will result in an annual saving in the range of 4–8 Mt of fuelwood (59–113 PJ). Moreover, even when the investment cost of the cooking stoves is considered, ICSs yield economic savings to fuelwood consumers compared to traditional stoves. The total savings during the first year of implementation would be in the range of 19–152 US$/stove. [ABSTRACT FROM AUTHOR]

Dark fermentative H 2 production is a promising approach since it requires minimal energy input as compared to other conventional methods of hydrogen production. Moreover, a wide variety of low cost-feedstock can be used that are released in the environment, thus providing an added advantage of waste management. This paper reviews the application of genomic and proteomic approaches to heterotrophic hydrogen production that could be useful in improvement of the same. Molecular techniques like polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) are conventionally used for microbial profiling of mixed consortia. An impending application of molecular techniques like terminal-restriction fragment length polymorphism (T-RFLP), ribosomal intergenic spacer analysis (RISA), quantitative PCR (qPCR), single strand conformation polymorphism (SSCP), fluorescence in situ hybridization (FISH) and fluorescence activated cell sorting (FACS) could be potentially used for advanced and rapid microbial characterization. Molecular techniques like gene overexpression, homologous recombination, gene knockout and antisense RNA are extensively used for improvement of hydrogen production processes. Challenges of applying above contemporary molecular techniques in thermophilic biohydrogen production processes were also studied. Use of proteomics helps in understanding the effect of genetic improvement leading to changes in entire proteome of the organism. Moreover, it is a useful tool for study the functional aspect of overexpression, site directed mutagenesis, random mutagenesis etc. towards improvement of H 2 production. Thus the study of genomic and proteomic techniques improve understanding of dark fermentative hydrogen production processes. [ABSTRACT FROM AUTHOR]

Biofuels are important substitute for fossil fuel with the advantages such as susatainablility, environmental friendly and good adaptability. In the last 10 years, biofuels development has been driven by the government policies. Many countries and areas have authorized laws and regulations to ensure the sustainable development of biofuels. By the support of the government, some biofuel projects have been commercialized. This paper reviews the national biofuel policies and strategy plans of the world׳s leading states, the government has provided sustained and cost-sharing privileges decreasing subsidies for the whole process from feedstock, from experimentation to industrialization of bioenergy industry in order to reduce investment risk. As a result of these supports, bioethanol and biodiesel have commercialized in several states, aviation biofuels are developing rapidly in the support of world׳s major airlines and US military. While there is political debate over the impact of biofuels on climate change and food security, it would be a challenge for the policy makers to continue trends of biofuels production while complying with sustainable production requirements. [ABSTRACT FROM AUTHOR]

Algae is generally regarded as the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Hydrothermal liquefaction is the method of dissolving organic compounds in subcritical water at high ion product, which can accelerate the acid-catalyzed and hydrolytic decomposition of algal macromolecules. This promising process converts different algal strains with high moisture content to high bio-oil yields with lower coke and lower energy consumption in comparison to other methods. The properties of the resulting bio-oil are clearly affected by parameters such as temperature, reaction time, algae species, algae concentration, reaction atmosphere, and catalysts, in subcritical water reaction conditions. This paper will provide an extensive review of the updated results on the hydrothermal liquefaction of microalgae. Including summary on the conversion of major compounds in microalgae and products related to the process and the influences of reaction conditions, catalysts and hydrotreating with comparing the variation tendencies and main results reported. [ABSTRACT FROM AUTHOR]

The increasing importance of lignocellulosic biomass as a renewable energy source has led to an acute need for reliable and detailed information on its assessment, consumption and supply. With the passage of China’s legislative targets for renewable portfolio standards, agricultural residue resources have the potential for an increasing role in meeting liquid fuels demand in China. An assessment of current and near future agricultural residue resources (including agricultural crop residues and secondary agricultural processing residues) in China at national scale was conducted. This paper gave the theoretical quantity, collectable quantity, usable quantity and potential quantity for liquid biofuel production of agricultural residues in China. The spatial and seasonal distributions of crop residues were analyzed. The theoretical output of crop residues in China at national scale in the near future were forecasted by means of an artificial neural network (ANN) model. The availability of agricultural residues in China was presented, as a result, the potential of liquid biofuels from agricultural residues was discussed. The ANN predicted results have shown that the theoretical output of crop residues in China at national scale will be up to 930.8 million tons in 2015. About 44 million tons per year of bioethanol or 131 million tons per year of bio-oil would have been produced, if the total usable output of agricultural crop residues were used to produce bioethanol through biochemical conversion process or bio-oil through fast pyrolysis, which could replace 26.9 million tons of gasoline or 58.2 million tons of diesel at national scale in 2015, respectively. The above results will be helpful for commercialization of bioenergy industry and their market-oriented development strategy, so as to accelerate the development of industrialization of biofuel technologies. [ABSTRACT FROM AUTHOR]

The increase in energy prices and the stagnation of sales prices of the main agricultural commodities required a rethinking of farm production strategies. Since during the last years, thanks to a series of policies aimed at promoting renewable sources it has been a rapid diffusion of lignocellulosic biomass species, this paper aimed at evaluating the economic feasibility of the introduction of eucalyptus ( Eucalyptus spp.) as energy crop for farmers of Southern Italy, by comparing it with traditional crop rotations. In particular, economic analysis has been carried out in a representative case study located in the Sicilian hilly hinterland where, in 2013, it has been built a biomass plant for energy production. However, results showed that introduction of eucalyptus for biomass production is less profitable for farmers than traditional crops, considering the incompressibility of production costs and the actual market price of woodchips. [ABSTRACT FROM AUTHOR]

Abstract: Using wastewater as resource for microalgal cultivation was seriously considered as a promising approach for sustainable biomass and lipid production. The proper selection of microalgal species is the foundation and key point to achieve this objective. This paper reviewed the recent status of microalgal cultivation in wastewater, including the characteristics of microalgal species used in recent studies, the performance of different microalgal species in different types of wastewater, the commonly-used isolation methods of microalgal species adaptable to the growth in wastewater, and the evaluation criteria of microalgal species. It was found that microalgal biomass and lipid production in wastewater were comparable to those in artificial culture medium, although most of the data was obtained in sterilized wastewater. Among all microalgal species involved in this review, Botryococcus braunii, Chlorella pyrenoidosa and Chlamydomonas reinhardtii showed superior performance in certain studies. However, no microalgal species has been demonstrated to meet all the requirements for large-scale biomass production in wastewater. Thus, the efforts on microalgal species isolation and characterization should still be promoted. On the basis of all the information, this review explored the limitations of recent studies and future research needs on this topic. [Copyright &y& Elsevier]

Abstract: The depletion of the fossil fuel supply and the environmental pollution caused by fossil fuel combustion have become major worldwide problems. Biomass is a renewable resource that has the potential to replace fossil fuels. One of the valuable biomass products is bio-methanol, which can be used to generate electricity and power for portable applications. This paper discusses the potential of bio-methanol as a renewable resource taking into account the world demand, economic assessment, power density and possible applications. It therefore presents the unique properties of bio-methanol as a potential energy resource. It also discusses the various types of biomass that can be obtained from waste products and the different processes that have been developed for the production of bio-methanol fIn addition, it discusses the current problems facing bio-methanol production and the further technological improvements that are needed to support the future energy requirements. Overall, the yield of bio-methanol depends on the type of process used and the associated kinetic parameters of the conversion process. Catalysts have been used in the thermo-chemical and bio-chemical conversion of carbon dioxide into bio-methanol. Several advanced methods have been recently introduced to enhance the production of methanol, but further research is required before these can be used for large-scale bio-methanol production. [Copyright &y& Elsevier]

Abstract: The demands of energy and pollutant emissions reduction have motivated the combustion researchers to work on combustion improvement. Flameless combustion or high temperature air combustion has many features such as flame stability, low pollutant emission and uniform profiles of temperature compared to the other modes of combustion. Combustion of solid fuels likes biomass and wastes in flameless combustion conditions has not been investigated as comprehensive as combustion of gaseous fuels. The aim of using biomass in combustion is to reduce the pollutant emissions and to decrease the rate of fossil fuel consumption. In this review, combustion characteristics of biomass in flameless combustion are explained. The paper summarizes the research on the mass loss, ignition time, and NO x emissions during biomass flameless combustion. These summaries show that biomass under flameless combustion gives low pollutant emissions, low mass loss and it decreases the ignition time. [Copyright &y& Elsevier]