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The Tailor-made Fuels from Biomass (TMFB) project aims to develop renewable and environmentally friendly fuels suitable for internal combustion engines (ICEs). The TMFB fuels can be produced from lignocellulose, helping to avoid land competition with edible food for production. After years of research, 2-butanone, 2-methylfuran (2-MF), 2-methyltetrahydrofuran (2-MTHF), n-octanol, and di-n-butyl ether (DnBE), have been identified as the promising TMFB fuels that are suitable for ICEs. This paper first discusses the physicochemical properties of the above five fuels. It then reviews the experimentally measured fundamental combustion characteristics, including ignition delay and flame speed. In addition, progress in detailed chemical kinetic modeling of the TMFB fuels is also presented individually. These models are validated against measured experimental ignition delay or flame speed data. The reaction pathway analysis for the five fuels can be performed based on these validated kinetic models. Next, the effects of the above five TMFB fuels on the combustion and emission characteristics of ICEs are summarized. 2-Butanone and 2-MF can be used as gasoline replacement fuels for spark ignition engines. 2-MF and 2-MTHF can be used in compression ignition engines by blending with highly reactive fuels. N-octanol and DnBE are isomers and can be used either alone or as blended fuels for compression ignition engines. Both the advantages and disadvantages of the above-mentioned fuels used in ICEs have been discussed in this paper. Finally, the remaining research gaps in fundamental combustion characteristics and engine applications are discussed to guide future research directions. • A comprehensive summary of five TMFB fuels is given. • The physical and chemical properties of TMFB fuels are compared. • Experimental and kinetic modeling of the oxidation process are discussed in detail. • Their impacts on engine combustion and emissions formation are presented in detail. [ABSTRACT FROM AUTHOR]

Alkaline hydrogen peroxide (AHP) was first introduced in 1984. Its ability to selectively attack carbonyl and ethylene groups is proven to enhance the delignification process of lignocellulosic biomass. The capabilities of AHP in dissociating the recalcitrant matrix of biomass indicate its potential in improving the accessibility of biomass to achieve valorization. In this paper, the background information of AHP and its reaction pathways are provided. Moreover, the recent applications of AHP in biomass processing and biofuel production are discussed by highlighting the effects of AHP in process selectivity and biomass dissolution. This paper also aims to provide some insights on the advantages and disadvantages of utilizing AHP in a pretreatment process. Lastly, a technoeconomic and cost benefit analysis of two scenarios of AHP production are critically reviewed to highlight the feasibility of implementing AHP in large scale production. It was reported that, AHP pretreatments were compatible with wide range of biomass and subsequent enzymatic hydrolysis. Besides, it was found that the application of AHP sequential pretreatment of biomass could increase the production yield of various bio-products such as silica and lignin. On top of that, AHP pretreatment was found to be a mild pretreatment method that promoted inherent safer and greener process. However, the mild operation condition would require a prolonged period to achieve the necessary delignification. Through technoeconomic analysis, the high chemical cost has rendered the installation of recycle stream compulsory to achieve economic feasibility. Image 1 • Alkaline hydrogen peroxide could be operated at ambient pressure and temperature. • Alkaline hydrogen peroxide are compatible with subsequent bioconversion. • High lignin solubilization and polysaccharide retention promote biofuel yield. • Sequential pretreatments generate less inhibitory by-products to fermentation. • Alkaline hydrogen peroxide pretreatments with recycling are economically feasible. [ABSTRACT FROM AUTHOR]

Abstract A continually growing awareness of the finiteness of fossil fuel availability coupled with an ever better understanding of the negative effects of fossil fuel consumption has motivated a search for fuels that can be used in place of fossil fuels, but which can be derived from sustainable sources such as growable organic matter. The effects of using biodiesel in existing gas turbines has received less attention than the effects of its use in more traditional internal combustion engines, due to the challenges of using this fuel in the typical aviation environment. This paper will provide a basic knowledge of biodiesel production and qualities, some of the limitations of its use, and modeling techniques for determining its performance within certain applications. A significant part of this paper is focused on reviewing the current state of experimental validation of our understanding of biodiesel performance in gas turbines. Particularly the experiments conducted to date that have measured the gaseous emissions of gas turbines operated with biodiesel as a fuel are reviewed and discussed. The outcome of this study is that turbines are shown to operate quite similarly when operated with biodiesel as they do with jet fuel, but there are significant challenges concerning material compatibility, energetic content, and low temperature characteristics that must be overcome when using biodiesel for aviation purposes. These challenges are less substantial when turbines are operated at ground level, since ground level operations are not generally hindered by extremely low temperatures and limited volume and weight requirements. Unfortunately, very few experiments have been conducted and published concerning this subject. The paper also proposes further research to better understand and optimize the application of biodiesel to gas turbines. Graphical abstract fx1 Highlights • Previous experimental works on utilizing biodiesel in gas turbines are summarized and discussed. • Flue gas composition and engine performance is very comparable between Jet-A and biodiesel in gas turbines. • Biodiesel fuel consumption is higher than Jet-A due to lower comparative heating value. • Several challenges need to be addressed in order to use biodiesel as a fuel replacement for aviation gas turbines. [ABSTRACT FROM AUTHOR]

The recent and rapidly growing interest in biofuel as a green energy source has raised concerns about its impact on the prices, returns and volatility of related agricultural commodities. Analyzing the spillover effects on agricultural commodities and biofuel helps commodity suppliers hedge their portfolios, and manage the risk and co-risk of their biofuel and agricultural commodities. There have been many papers concerned with analyzing crude oil and agricultural commodities separately. The purpose of this paper is to examine the volatility spillovers for spot and futures returns on bio-ethanol and related agricultural commodities, specifically corn and sugarcane. The diagonal BEKK model is used as it is the only multivariate conditional volatility model with well-established regularity conditions and known asymptotic properties. The daily data used are from 31 October 2005 to 14 January 2015. The empirical results show that, in 2 of 6 cases for the spot market, there were significant negative co-volatility spillover effects: specifically, corn on subsequent sugarcane co-volatility with corn, and sugarcane on subsequent corn co-volatility with sugarcane. In the other 4 cases, there are no significant co-volatility spillover effects. There are significant positive co-volatility spillover effects in all 6 cases, namely between corn and sugarcane, corn and ethanol, and sugarcane and ethanol, and vice-versa, for each of the three pairs of commodities. It is clear that the futures prices of bio-ethanol and the two agricultural commodities, corn and sugarcane, have stronger co-volatility spillovers than their spot price counterparts. These empirical results suggest that the bio-ethanol and agricultural commodities should be considered as viable futures products in financial portfolios for risk management. [ABSTRACT FROM AUTHOR]

The major contributor to global warming is human-generated greenhouse gases (GHGs) emissions that pollute the air. GHGs emissions are a global issue dominated by emission of carbon dioxide (CO 2 ). Notably, CO 2 accounts for an estimated 77% of GHGs and thus has a huge impact on the environment. The capture, sequestration, and utilization of CO 2 emissions from flue gas are now becoming familiar worldwide. These methods are a promising solution to promote sustainability for the benefit of future generations. Previously, many researchers have focused on capturing and storing CO 2 ; however, less effort has been spent on finding ways to utilize flue gas emissions. Moreover, several issues must be overcome in the field of carbon capture and sequestration (CCS) technology, especially regarding the cost, capacity of storage and the durability of the storage reservoir. In addition, this paper addresses new technology in carbon capture and sequestration. To make CCS technology more feasible, this paper suggests a sustainable method combining CCS and biofuel production using CO 2 as a feedstock. This method offers many advantages, such as CO 2 emission mitigation and energy security through the production of renewable energy. Due to the many advantages of biofuels, the conversion of CO 2 into biofuel is a best practice and may provide a solution to pollution while encouraging sustainability practises. [ABSTRACT FROM AUTHOR]

There is a broad spectrum of BR (Biofuel Related) models. However the models are highly specific. Such models cannot flexibly support complex decision making activities to identify feasible trade-offs among many objective functions. They represent just one point of view; e.g. engineering, company economics. Therefore CBRMs (Complex Biofuel Related Model) are studied in this paper. CBRMs must cover additional aspects, e.g. macroeconomic, ecology, sociology and politics. Such models are inevitably unique, partially subjective, inconsistent, vague and multidimensional. AI (Artificial Intelligence) has developed a number of tools to solve such problems. Qualitative reasoning is one of them. It is based on the least information intensive quantifiers i.e. trends. There are just three trend / qualitative values: plus/increasing; zero/constant; negative/decreasing . There are many CBRM items related to soft aspects e.g. politics, taxation etc. which cannot be quantified by numbers. They are too vague. For example – if the political/sociological sensitivity of land ownership is increasing then the cost of biofuels is increasing . Such verbal knowledge item cannot be incorporated into a traditional numerical model. The paper describes developments of CBRMs based on expert knowledge and common sense. A consensus among experts is often not reached because of substantial subjectivity of experts’ knowledge. A qualitative intersection of CBRMs developed by several experts is simple. The case study presents a model based on integration of 10 heuristics using 9 variables e.g. Refinery Capacity, Cost of Biofuel Production, and Biofuel Demand . The result is represented by 13 scenarios. The paper is self-contained, no a prior knowledge of qualitative models is required. [ABSTRACT FROM AUTHOR]

Many countries have attached great emphasis on biofuel because it is universally acknowledged renewable and sustainable. However, there remain doubts regarding biofuel׳s renewability, cleanliness, and ecological friendliness. In addition, its impacts on income, employment, and food security have been widely discussed. Therefore, the effect of developing biofuel as an important method of resolving the energy crisis and climate change is questioned. Based on the rocketing concern on the multiple effects of biofuel, this paper provides a comprehensive and updated review of the literature on biofuel׳s ecological effects and socioeconomic effects. The literature included in this paper is selected English language papers being published since 2004. We find that existing studies have not arrived at a consensus regarding the ecological or the socioeconomic effects of biofuel. There remain uncertainty and doubts toward biofuel׳s renewability and cleanliness. Biofuel׳s impacts on water and biodiversity are also questioned. Although biofuel is widely regarded to have positive impacts on income and employment, many studies prove that biofuel influences food security negatively. Besides, biofuel׳s economic cost is likely to be the barrier to its promotion. Because of the uncertainty of biofuel׳s impacts, this study recommends cautious attitude toward biofuel development, especially for those countries where biofuel development would be inappropriate, and suggests that policy makers engage in “demand side management” instead of unsustainable “supply side management”. [ABSTRACT FROM AUTHOR]

Demographic change, dramatic population increase and rapid industrial growth are major trends emerging in Malaysia. Climate change and depletion of fossil fuel along with the rise in petroleum prices have forced the Malaysian Government to rethink strategies to be more in line with other developed countries including the decision to embark on renewable energy (RE) resources as a better source of energy amongst the global energy mix. The Malaysian Government is making frantic efforts to make policies, RE programmes and incentives more effective so as to promote and develop the use of RE. Malaysia is rich with fossil fuel but these are fast depleting. Although RE is necessary, current RE resources are still not enough. Therefore, exploration into other resources must be considered in order to meet future energy demands. The objective of this paper is to identify the potential of available renewable energy resources in Malaysia as well as the country׳s current implementation strategies. This paper also discusses the different RE policies in Malaysia. In order to determine the potential of RE, various sources and published materials in conferences, international journals and information released by relevant government bodies and miscellaneous resources are used. This research has revealed that among all the renewable energy sources that are present in Malaysia, biomass and solar energy are the most prospective ones. Plus, renewable energy (RE) sources are quite advantageous as they are free from greenhouse gas (GHG) emissions and related global warming effects. They can also be applied in off-grid electricity generation for rural communities. [ABSTRACT FROM AUTHOR]

Biofuel production has stood out at the international level on account of its more environmentally sustainable characteristics and the potential to promote rural development in developing countries. In Brazil, biodiesel is being produced through legislation requiring the addition (currently 7%) of biofuel to petroleum diesel. The federal program (PNPB) aimed the social inclusion of small farmers and diversification of Brazilian matrix by incentives regional crops production. The possibility of broadening raw material sources for biodiesel production benefits the Brazilian competitiveness. At the same time, facing the vast varieties of raw materials available in this country, it is a challenge to figure out which crop would be more appropriate to this chain. The palm species Acrocomia aculeata ( macaúba ) could provide an alternative resource for energy diversification in Brazil and Latin American countries. The crop species has drawn attention due to its high productivity rates and because it is not used for food purposes. In this sense, this paper examines the opportunity of biodiesel production from A. aculeata as a potential source for future energy supply, particularly for biodiesel, especially in Brazil. This paper presents A. aculeata and some points that allow compare with other crops. Several related aspects are covered in this paper, such as economics, botanical description, the extraction and compositions, physical and chemical properties of crude A. aculeata oil and fatty acid composition of A. aculeata . [ABSTRACT FROM AUTHOR]

The production of biodiesel through enzymatic routes has attracted significant attention, mainly because this can be regarded as a "green route" for the manufacture of fuels. In this way, an advanced bibliometric analysis comprising the global scientific production of biodiesel through immobilized enzymes was conducted. Thus, 923 papers were retrieved, analyzed, and classified according to the reported substrates, enzymes, supports, immobilization procedures, and reactors. Researchers from 748 institutions of 64 distinct countries authored the analyzed articles, showing the widespread interest in these technologies, although 10 countries concentrate more than 80% of the total number of documents published in this area, including China (23%), Brazil (17%), and India (11%). Particularly, most papers reported the use of vegetable oils (67%) as raw materials. In the last decade, approximately 80% of the published research focused on the use of supports to manufacture immobilized and insoluble biocatalysts. Enzymes have been obtained mostly from fungal sources (64%), especially lipases produced by Thermomyces lanuginosus (14.4%). Among the available commercial immobilized biocatalysts, Novozym 435 is certainly the one cited most frequently (55.9%) followed by Lipozyme RM IM (13.7%) and Lipozyme TL IM (16.7%). Additionally, the majority of the manuscripts reported the use of stirred tank reactors (83.0%) to perform the enzymatic reactions. Based on the surveyed literature, research trends indicate that new technologies are being developed to turn the enzymatic production of biodiesel more sustainable and economically viable, based mainly on the use of more active biocatalysts, more sustainable enzyme supports, and low-cost residues as raw materials. • Advanced bibliometric review about the production of biodiesel by immobilized enzyme was performed. • Chinese and Brazilian scientific communities are the most active in this field. • Novozymes 435 is the commercial biocatalyst used most often in this field. • Emerging technologies were identified for the synthesis of enzyme supports. • Sustainable supports and low-cost feedstocks are trends in the biodiesel production field. [ABSTRACT FROM AUTHOR]

Renewable energy sources can help combat climate change but knowing the land, water and carbon implications of different renewable energy production mixes becomes a key. This paper systematically applies land, water and carbon footprint accounting methods to calculate resource appropriation and CO 2 eq GHG emissions of two energy scenarios. The '100% scenario' is meant as a thinking exercise and assumes a complete transition towards bioenergy, mostly as bioelectricity and some first-generation biofuel. The 'SDS-bio scenario' is inspired by IEA's sustainable development scenario and assumes a 9.8% share of bioenergy in the final mix, with a high share of first-generation biofuel. Energy inputs into production are calculated by differentiating inputs into fuel versus electricity and exclude fossil fuels used for non-energy purposes. Results suggest that both scenarios can lead to emission savings, but at a high cost of land and water resources. A 100% shift to bioenergy is not possible from water and land perspectives. The SDS-bio scenario, when using the most efficient feedstocks (sugar beet and sugarcane), would still require 11–14% of the global arable land and a water flow equivalent to 18–25% of the current water footprint of humanity. In comparative terms, using sugar or starchy crops to produce bioenergy results in smaller footprints than using oil-bearing crops. Regardless of the choice of crop, converting the biomass to combined heat and power results in smaller land, water and carbon footprints per unit of energy than when converting to electricity alone or liquid biofuel. • The greenhouse gas emission savings of bioenergy entail large land and water use. • Land, water and carbon footprints of biofuels and bioelectricity are calculated. • A dynamic energy feedback loop is used to clarify gross and net footprints. [ABSTRACT FROM AUTHOR]

Abstract: As the world confronts a reported food shortage and rising fuel prices, scientists around the globe are scrambling to develop biofuel feedstocks that would not divert food crops to energy. It is apparent that the demand for biodiesel is expected to increase in near future and although many edible oils might be the cheapest feedstock for biofuel production. But it may not be sustainable source to meet this increasing demand. This justifies the need to use non-edible oil seeds that can be the reliable sustainable feedstock for biofuel production. Furthermore, most of the non-edible seeds bearing trees have the potentials of reclaiming wasteland and does not compete with food crop for limited growing regions. It thus becomes imperative to search for dedicated non-edible feedstocks and their suitability for biodiesel production. This paper attempts to make an assessment of current energy scenario, potential of non-edible oil over edible oils, selected non-edible oil seeds as biodiesel feedstocks, impact of biofuel on environment and future direction. Experimental analysis by different researchers on these non-edible oils showed their great potential as feedstocks for biodiesel production. This paper also reviews the biology, distribution and chemistry of selected non-edible oil seeds plants. [Copyright &y& Elsevier]

This virtual special issue published in Renewable and Sustainable Energy Reviews contains 25 high-quality selected extended papers presented at the HERAKLION 2019 7th International Conference on Sustainable Solid Waste Management held in Heraklion, Crete in Greece from 26th to June 29, 2019. The articles published in this special issue focus on recent developments in sustainable waste-to-energy systems and waste management practices and highlight the critical challenges and potential solutions. The editorial paper aims to give a brief overview of the key findings and future perspectives proposed in these 25 selected papers. It is worth noting that although the articles presented in this special issue covered a wider range of topics, they are categorized into five categories. These include the latest developments in 1) waste-to-energy technologies, 2) biofuels and bioenergy, 3) waste valorization, 4) emerging renewable and sustainable energy systems, and finally, 5) biorefineries and circular economy. • Twenty five high quality peer-reviewed papers were selected from HERAKLION 2019 Conference. • The mian theme of sustainable waste-to-energy systems catogorised into five topics. • It will support advancement of waste-to-energy technologies and circular economy. [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]

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 Northeast region of Brazil has low levels of human development and a marginal environment subject to chronic water scarcity. This paper assesses the potential impacts of bioenergy production from local varieties of castor oil plant and jatropha that could reduce the import of energy in the region, while developing its economy. Biodiesel systems based on these crops can be suitable for the Northeast region as they have low water needs, and are either indigenous or have shown excellent adaptation to the local climate. Apart from biodiesel production, the residue from their processing can be a valuable resource usable for biogas production and bio-fertilizers. Using the ecosystem services approach, five land management alternatives are compared: (i) Caatinga woodland (a type of dry savannah native to the region), (ii) a scheme of local jatropha varieties and vegetation for Caatinga forest restoration, (iii) a crop rotation scheme of castor oil plant and cowpeas, (iv) cowpea mono-cropping, and (v) pasture. Based on the analysis of secondary data, some provisioning and regulating services were assessed quantitatively, while others qualitatively. The results suggest that the conversion of (i) cowpea mono-cropping to a rotation of cowpeas and castor and (ii) degraded pastures to a jatropha-Caatinga forest restoration scheme can provide a bundle of provisioning, regulating and supporting ecosystem services. Feedstock for bioenergy is the most important ecosystem service derived from these multi-functional landscapes. In particular converting pasture to a jatropha-Caatinga forest restoration scheme could provide per hectare 0.7 t of oilseeds for biodiesel production and 1.8 GJ of usable energy, in the form of biogas from the residual seedcake. The castor-cowpea rotation scheme could provide per hectare 1.5 t of oilseeds for biodiesel production together with 2.2 GJ of usable biogas energy, per hectare. [ABSTRACT FROM AUTHOR]

Application of Soybean including its bean virgin oil and residual straw in a whole-crop biorefinery was highlighted. Compared to other conventional raw materials, soybean contains all the necessary block raw materials to constitute a biorefinery unit. Virgin oil extract of soybean can be used to produce biodiesel through transesterification reaction. Soybean residual straw contains a sufficient amount of cellulose, hemicelluloses and lignin for producing a variety of biomaterials, biofuels and biochemicals. Pulp mills which produce cellulosic fibers look like a “biorefinery” plant: nearly pure separated cellulose are used today mostly as paper; through the process after separation and solubilization, lignin and hemicelluloses are remained as “black liquor” and incinerated in recovery boiler. The main demands of power for running pulp mill comes from this recovered heat. The heat thus produced covers largely the energy needs of the pulp mill, which may then become a net producer of electricity. This review gathers the different technologies of soybean processing in a third generation of biorefinery, so called whole crop biorefinery. Biochemical transformation of soybean oil to biodiesel was explained following the processing of straw. Then, extraction of biopolymers rom soybean straw with different procedures was described. Finally, integration of the whole crop in a biorefinery system was proposed to produce different value added biofuels, biomaterials and biochemicals. [ABSTRACT FROM AUTHOR]

Fuel security, economics and climate change issues are creating a requirement for alternative renewable fuels. Bioethanol produced by algal biomass is becoming increasingly popular all over the world due to the sustainability of feed stock and environmentally friendly nature. This review paper describes the bioethanol production technology from algae using various cultivation, harvesting, extraction and commercialization techniques and its environmental perspectives. The economic sustainability of algae-derived bioethanol biofuel depends on the cost of production that could be minimized by producing valuable secondary by-products, which is the aim of current algal biofuel research. Future technologies with sufficient potential for maximum extraction capacity and minimal downstream processing using low cost feedstock will address the cost-effectiveness of renewable bioethanol biofuel. [ABSTRACT FROM AUTHOR]

Due to rapid industrialisation and use of advanced technologies there has been increase in the consumption of fossil fuels, especially petroleum. Increasing needs are reciprocally proportionate to diminishing reserves of coal and petroleum. So, the exaggerated to be fulfilled and to curb the problem of increasing fuel prices; researchers are putting their efforts to produce an alternative fuel from replenish able resources on large scale. Biodiesel itself is proving to be a reliable and competent competitor to non-renewable petroleum which is being produced from commonly accustomed plants for instancerapeseed, soybean, sunflower and palm etc. But, complication is that it becomes a problem for in-availability of these oils for foods. Now non-edible raw materials oils such as Pongamia, Jatropha, Mahua, Moringa seed oil etc. have been used to raise the standard of these oils and being produced to complete the level of petroleum and be proven as the best resources for biodiesel production in all approaches both technically and economically. In this paper emphasis has been laid down to review the impact of higher alcohols, use of different raw materials for biodiesel preparation and effect of their composition on Oxidation Stability and Cold Flow properties. Moreover, various production technologies used to produce biodiesel were also reviewed and comparison was done among them for better yield. Further, an attempt has been made to investigate the effect of higher alcohols on biodiesel yield and its properties. The study concludes that oxidation stability depends upon unsaturation mainly linoleic acid and lenolenic acid. Moringa olifera , Moroccan frying oil, Schleichera oleosa L. oil, Moringa peregeria are prospective oils as per oxidative stability characteristics. In contrast to it, cold flow properties depend upon saturation and suggests that having more saturated fatty acids result in poor cold flow properties. [ABSTRACT FROM AUTHOR]

The estimations of land use changes and greenhouse gas emissions induced by biofuels remain highly controversial. After some first estimates in 2009, the California Air Resource Board releases new estimates in 2014. This paper explains two striking new results. First, the absolute reduction in the estimate of average US soya biodiesel is much greater than the reduction in the estimate of average US corn ethanol (by respectively 33 and 10 g CO 2 eq/MJ). According to the new estimates, these two biofuels now induce more similar greenhouse gas emissions. Second, the newly reported EU and US canola biodiesel estimates are very different (respectively greater than 35 and 10 g CO 2 eq/MJ). Using the public and transparent methodologies developed by the California Air Resource Board, we find that these two striking results are mostly explained by some weak initial economic data. In both cases, the undervaluation of the initial oilmeal productions generates upward bias in the land use changes and carbon emission estimates by reducing the co-product effects. We find that the new closer estimates reported for the US soya biodiesel and corn ethanol are explained by an appropriate revision of the world production of oilmeal and the inclusion of oilmeal trade flows. We also find that the reported significant difference between the EU and US canola biodiesel estimates nearly disappears when the initial data on European land values, oilmeal production and trade values are improved. We then emphasize that any economic analysis is only as valuable as the quality of the supporting data allows. The current focus in academic and policy circles on unobserved elasticity values to assess biofuel impacts is not sufficient. [ABSTRACT FROM AUTHOR]

The paper describes an approach to landscape design that focuses on integrating bioenergy production with other components of environmental, social and economic systems. Landscape design as used here refers to a spatially explicit, collaborative plan for management of landscapes and supply chains. Landscape design can involve multiple scales and build on existing practices to reduce costs or enhance services. Appropriately applied to a specific context, landscape design can help people assess trade-offs when making choices about locations, types of feedstock, transport, refining and distribution of bioenergy products and services. The approach includes performance monitoring and reporting along the bioenergy supply chain. Examples of landscape design applied to bioenergy production systems are presented. Barriers to implementation of landscape design include high costs, the need to consider diverse land-management objectives from a wide array of stakeholders, up-front planning requirements, and the complexity and level of effort needed for successful stakeholder involvement. A landscape design process may be stymied by insufficient data or participation. An impetus for coordination is critical, and incentives may be required to engage landowners and the private sector. Hence devising and implementing landscape designs for more sustainable outcomes require clear communication of environmental, social, and economic opportunities and concerns. [ABSTRACT FROM AUTHOR]

Biofuel production from lignocellulose has recently been gaining much more attention as a result. One major problem of using lignocellulosic materials for the production of biofuel is the low accessibility of cellulose to enzymes and microorganisms. Therefore, pretreatment of lignocellulose is a critical step in biofuel production from such materials. Of the pretreatments, fungal treatment has become an important process due to its low energy demands and selective degradation of lignin and hemicellulose. This capability comes from the unique enzymatic systems, cellulolytic and ligninolytic enzymes, especially in white rot fungi. The low energy demand of fungal pretreatment has generated interest in studying the applicability of fungal pretreatment for biofuel production from woody materials. The most significant drawback of fungal pretreatment is the lengthy time required for the process. Combining fungal pretreatment with other pretreatment methods might reduce the time necessary for the whole process to operate. It can also introduce cost-effectiveness. Thus combining fungal pretreatment with other physical and chemical methods has been recently contemplated. This paper provides a comprehensive review of current fungal pretreatments and feasibility for biofuel production, with a focus on combining fungal pretreatment with other methods. The advantages and disadvantages of all physical and chemical methods were also briefly reviewed. The applicability of the combination of fungal with other pretreatment methods has been considered in a number of recent publications. To be commercially attractive, both energy demand and processing time should be reduced. In terms of energy demand reduction, combined fungal physico-chemical pretreatment has been effective. However, the lengthy time taken for the whole process has not been significantly improved upon. A great deal of work is still required to be done regarding time reduction for the process (combined fungal-physico chemical pretreatment). Therefore, it seems to remain an open field for research and process development. [ABSTRACT FROM AUTHOR]

This study reviewed papers related to biofuel emulsion, principally assessing the use of biofuel emulsion. The discussion is focused mainly on three active areas of emulsified biofuel, namely, exploration of various factors affecting the preparation of stable emulsion and its fuel properties, investigation of the effect of water concentration on physicochemical properties of fuel, and observation of the improvement and degradation of combustion, performance, and emission characteristics and the possible methods to enhance these characteristics. [ABSTRACT FROM AUTHOR]

The potential for sugarcane ethanol from Brazil to mitigate GHG emissions is undeniable, but the way that ethanol is produced during the agricultural and industrial phases will ultimately determine its benefits to society. In this paper, we evaluate the environmental impacts of sugarcane agriculture and ethanol production in Brazil as management practices continue to change and production expands to new frontiers. We focused our evaluation on the impacts on water, atmosphere, and soils, including how the application of organic and inorganic fertilizers and the accumulation of crop residue in the field affect emissions of greenhouse gases (GHG). We also addressed the impacts of land use changes on threatened biomes and discussed some of the present obstacles regarding conservation and restoration efforts. We concluded that, since a similar assessment was put forth in 2008, our knowledge about the environmental impacts of sugarcane ethanol in Brazil has advanced with regard to soil degradation, nitrogen dynamics, and soil carbon stocks. However, more information is still needed about the impacts of the increasing use of pesticides, herbicides, and fertilizers in sugarcane agriculture, especially on water resources. Furthermore, without a better understanding about how landscape fragmentation affects the biodiversity of terrestrial and aquatic tropical ecosystems and the services they provide, policies created to protect and restore them may be ineffective. On the other hand, the use of presently available scientific information to end unsustainable farming and the implementation of conservation strategies proposed by the Brazilian Forest Code could be a first step to guarantee that ethanol is produced more sustainably in Brazil. [ABSTRACT FROM AUTHOR]

Even though considerable strides have been made in the development of effective technologies for the production of different biofuels in some commercial quantities, global consumer patronage in biofuel utilisation has been discouraging. This has triggered significant inquisitions and research into different key aspects of the biofuel supply chain some of which are; techno-economic innovations targeted at reducing production cost, product marketing and packaging, and sustainable resources for biomass generation. This paper seeks to investigate biofuel marketing modalities beyond the current scope of a majority public sector industry to aid the development and promotion of biofuels to commercial and public sectors. The need for marketing in the biofuel industry is explored to identify innovative strategies, trending capacities, and key success factors to revolutionise marketing schemes with the potential to predict future trends. Scholarly positions on effective strategies using well-known marketing paradigms are discussed to suit the need of the industry. A proposal for the application of a strategic marketing framework built on sustainability precept is put forward, concluding that sustainable marketing (green and social marketing) could be used concurrently and continuously to improve growth and development through increased sales and competitive scoping. [ABSTRACT FROM AUTHOR]

This review paper analyses the potential environmental impacts and economic viability of producing biofuel from lignocellulosic biomass resources in various countries of the world. In many developed and developing countries, lignocellulosic biomass is a significant feedstock for bioenergy used in industrial sector for power generation but the fact remains that the detail study on current status of lignocellulosic utilization for bioenergy industry is still estimated and partial. In this context, the present study focuses its efforts to have country based database able to provide a detail and comprehensive information on country specific agricultural policies, residue production and their utilization in different energy sectors. Much more information will have to be gathered on the use and availability of residues, and also, taking into consideration the strong need for R&D on lignocellulosic resources based biofuel production, a comprehensive survey of innovative technologies based on both thermochemical and biochemical processes, able to convert lignocellulosic biomass resources into green biofuel, is discussed. [ABSTRACT FROM AUTHOR]

Many authorities have reached the conclusion that using fossil fuels, as the main source of energy to satisfy the increasing global energy demand, is ultimately unsustainable. This is because of depleting resources, and also because, if this approach is followed, emissions of carbon dioxide would continue to build up. Consequently, research on biofuel, that is fuel made from biomass, derived from materials that were recently living, has attracted attention. In this context, the generation of biofuels from algae shows promise for the following reasons. The algae can be grown quickly, all the materials produced are non-toxic and biodegradable, and during this growth there is an opportunity to cause greenhouse gas fixation. Also, since growing algae does not need arable land, it can be grown without competing with food or feed crops, the fuel derived from it being a “third generation” biofuel. This paper describes different types of algae (microalgae and seaweeds), and presents different technologies employed in making biofuels (biogas and biodiesel) from them. [ABSTRACT FROM AUTHOR]

Oil palm wastes (OPWs) are important biomass resources, and approximately 127 million tons of OPWs are generated from the oil palm industry annually in Malaysia. The scientific and reasonable utilization of OPWs is essential to economic and environmental sustainability in the country. Pyrolysis is a mature and revolutionary technology that can convert OPWs into biofuel. The conversion of OPWs into biofuel is in accordance with the national conditions of Malaysia and can simultaneously address the problems of fossil fuel shortage and environmental deterioration. Therefore, Malaysia is the most active country in the research of OPWs pyrolysis and has achieved fruitful results. Bio-oil produced from the catalytic co-pyrolysis of OPWs with hydrogen-rich materials exhibits remarkable fuel properties. Biochar generated from OPWs pyrolysis presents huge application potential as an absorbent, catalyst, soil conditioner, and carbon sequestration agent. Consequently, the paper provides a comprehensive review of OPWs pyrolysis and lays the foundation for the exploitation of OPWs resources. [Display omitted] • Malaysia is the most active country in the research of OPWs pyrolysis. • Effects of reactors and conditions on OPWs pyrolysis are detailed. • OPWs-based biochar exhibits great application potential in various fields. • Building a pyrolysis plant near the oil palm mill is a viable and economic method. • OPWs pyrolysis has great commercial potential and economic value in Malaysia. [ABSTRACT FROM AUTHOR]

From 1999 to 2013, in a 14 years׳ period of time, rural electrification programs brought access to electricity to 16 million rural inhabitants in Brazil. Approximately 155,000 rural households remain without access to electricity in the Amazon Region, conforming very isolated communities that cannot be supplied by the expansion of the existing grid. To supply electricity to these communities, off-grid generation through diesel fuel has traditionally been the only option considered. The Amazon Region has a huge potential in renewable energy, specially: hydraulic, biomass and biofuels, solar as well as wind in the coast. The Brazilian Government has started to consider the use of these local renewable sources for the electrification of isolated communities. Several experimental projects have been deployed, supplying electrical power through appropriated off-grid renewable energy technologies: run-of-the-river and hydrokynetic, biomass (direct burning or gasification), biofuels and vegetable oils, and hybrid (solar–wind–diesel). Regarding these technologies, the most significant projects conducted in the region were evaluated. Analyzing the costs, technical and social issues as well as the performance of these systems, after a 10 year׳s evaluation period, this paper shows that some renewable energy technologies have proven to be a more convenient and economic option than electricity generation through diesel, in these isolated communities. [ABSTRACT FROM AUTHOR]

Vegetable oils and animal fats represent promising alternatives to diesel engine fuel because they can be obtained from different feedstocks and renewable sources; also their properties are close to diesel fuel. The direct use of these biofuels as a diesel engine fuel can cause several problems in engine performance and emissions. In order to obtain a more engine-friendly fuel, it is necessary to change the biofuels’ properties for which different methods have been used. One of the possibilities is using emulsification techniques in order to obtain emulsified biofuels (emulsions or microemulsions); through this method it is possible to lower viscosity and improve the atomization. However, emulsification techniques applied to vegetable oils and animal fats have not been studied thoroughly. For this reason, this paper presents an overview on the formulation and characterization of the emulsified biofuels using vegetable oils and animal fats, as well as the main experimental results reported about its use as a diesel engine fuel in the scientific literature. [ABSTRACT FROM AUTHOR]

The prospect of biofuels as a transport alternative fuel in Australia is reviewed and discussed in this paper. The Australian transport sector is the second largest energy consuming sector which consumes about 24% of total energy consumption. A part of this energy demand can be met by ecofriendly biofuels. A wide array of different biofuels feedstocks including Australian native species, their distributions, oil content, traditional uses are reviewed and listed in the descending order of their oil content. The world biofuel scenario as well as the 20 largest biofuel production countries and their mandates on biofuels blending with petroleum diesel are presented. Australia’s biofuel production, consumption, production facilities and future investment projects are also reviewed and discussed. The study developed a biofuel supply chain for Australia and found that the second generation biofuels have better prospects as a future alternative transport fuel in Australia. These biofuel feedstocks are readily available and can overcome the shortcomings of the first generation biofuels, such as socio-economic, environmental and food versus land use challenges. Although some research is in progress, further study is needed on the process development of second generation biofuel production at commercial scale in Australia and abroad. [ABSTRACT FROM AUTHOR]

The recent energy independence and climate change policies encourage development and utilization of renewable energy such as bioenergy. Biofuels in solid, liquid, and gaseous forms have been intensively researched, produced, and used over the past 15 years. This paper reviews the worldwide history, current status, and predictable future trend of bioenergy and biofuels. Bioenergy has been utilized for cooking, heating, and lighting since the dawn of humans. The energy stored in annually produced biomass by terrestrial plants is 3–4 times greater than the current global energy demand. Solid biofuels include firewood, wood chips, wood pellets, and wood charcoal. The global consumption of firewood and charcoal has been remaining relatively constant, but the use of wood chips and wood pellets for electricity (biopower) generation and residential heating doubled in the past decade and will increase steadily into the future. Liquid biofuels cover bioethanol, biodiesel, pyrolysis bio-oil, and drop-in transportation fuels. Commercial production of bioethanol from lignocellulosic materials has just started, supplementing the annual supply of 22 billion gallons predominantly from food crops. Biodiesel from oil seeds reached the 5670 million gallons/yr production capacity, with further increases depending on new feedstock development. Bio-oil and drop-in biofuels are still in the development stage, facing cost-effective conversion and upgrading challenges. Gaseous biofuels extend to biogas and syngas. Production of biogas from organic wastes by anaerobic digestion has been rapidly increasing in Europe and China, with the potential to displace 25% of the current natural gas consumption. In comparison, production of syngas from gasification of woody biomass is not cost-competitive and therefore, narrowly practiced. Overall, the global development and utilization of bioenergy and biofuels will continue to increase, particularly in the biopower, lignocellulosic bioethanol, and biogas sectors. It is expected that by 2050 bioenergy will provide 30% of the world’s demanded energy. [ABSTRACT FROM AUTHOR]

Hydrothermal processing is an important thermochemical conversion process that is used to convert biomass into valuable products or biofuel. The process is usually performed in water at 250–374 °C under pressures of 4–22 MPa. The biomass is degraded into small components in water. Based on the target products, i.e., bio-oil, bio-gas or bio-carbon, the process conditions (temperature, pressure and time) are chosen. There has been significant effort in evaluating various biomass resources for hydrothermal processing because the process is suitable for any type of biomass including the co-utilization of biomass with waste materials. Additionally, because most biomass resources have high moisture contents, the most efficient way to process them is through hydrothermal processing. To understand hydrothermal biomass processing and the degradation pathway of biomass, it is necessary to understand the properties of water under hydrothermal conditions (i.e., subcritical and supercritical). In this respect, the physicochemical properties of water under subcritical and supercritical conditions and the interactions of water with biomass are discussed in the present paper. This review focuses on the hydrothermal processing of biomass and identifies the characteristics of various types of hydrothermal processing products. Additionally, this review provides an overview of the available biomass, the use of biomass as an energy source and related conversion technologies. [ABSTRACT FROM AUTHOR]

Abstract: The potential of algae-based biofuels to replace petroleum fuels and mitigate greenhouse gas production through microalgal photosynthesis has long been recognized. However, currently there are no commercial algae-to-fuels technologies that can overcome techno-economic barriers and address serious sustainability concerns. Coupling microalgae cultivation with wastewater treatment is considered as one of the most promising routes to produce bio-energy and bio-based byproducts in an economically viable and environmentally friendly way. This paper critically reviews the current status of this specific niche research area covering utilization of different types of wastewaters as media for algae cultivation, microalgae selection, bioreactor type, cultivation mode, environmental factors and operational parameters as well as harvesting techniques and production of a broad spectrum of biofuels and byproducts through various conversion pathways. Future development of practical solutions to key problems and integration of advanced algae cultivation and wastewater treatment, and system analysis approach to the evaluation of economic feasibility and sustainability of wastewater-based algal biofuel production are also discussed in depth. [Copyright &y& Elsevier]

Abstract: Present energy situation of the world is unsustainable due to unequal geographical distribution of natural wealth as well as environmental, geopolitical and economical concerns. Ever increasing drift of energy consumption due to growth of population, transportation and luxurious lifestyle has motivated researchers to carry out research on biofuels as a sustainable alternative fuel for diesel engine. Renewability, cost effectiveness and reduction of pollutants in exhaust gas emission are promoting biofuels as a suitable substitute of diesel fuel in near future. This paper reviews the suitability of feedstock and comparative performance and emission of palm, mustard, waste cooking oil (WCO) and Calophyllum inophyllum biofuels with respect to diesel fuel from various recent publications. Probable analysis of performance and emission of biofuel is also included in further discussion. Palm oil has versatile qualities in terms of productivity, oil yield and land utilization. But tremendous demand of edible oil is motivating the use of non-edible vegetable oils as biofuel feedstock. Mustard oil is a promising new biofuel especially regarding NO x reduction. WCO is one of the most economic sources of biofuel which efficiently helps in liquid waste management and prevents recycling of used oil, injurious to human health. C. inophyllum is completely non-edible and trans-esterified oil shows similar engine performance and emission characteristics like other biofuels. Limited data were published regarding mustard and C. inophyllum as their use as biofuel is still in primary state compared to palm or WCO. Therefore, in depth research needs to be carried out on these two oils to use them effectively as alternative fuels. [Copyright &y& Elsevier]

Abstract: Garden waste biomass is a potentially underutilized renewable biofuel feedstock, which is increasing dramatically with rapid urbanization worldwide. China has experienced fast-paced urbanization over the past three decades: the settlement area has increased at a rate of 6.1% annually, with greenspace increasing by 12.7% annually from 1996 to 2008. This paper provides a synthesis of literature and experimental data to trace the potential of garden waste biomass for green renewable energy production in China. Our results show that the total potential biofuel produced by garden waste biomass was estimated at 260 petajoules (PJ), accounting for 20.7% of China's urban residential electricity consumption, or 12.6% of China's transport gasoline demand in 2008. Thus the use of garden waste biomass for energy production will contribute to the construction of low-carbon cities. However, there are still many difficulties—the main challenges are how to quantify the available garden waste biomass accurately, and technical and financial issues with the exploitation of garden waste biomass for energy production. Finally, we provide several practical suggestions for the future development of garden waste biomass for energy production. The use of garden waste for energy production in urban areas could be a win–win approach for mitigating both the burden of disposed costs and the energy crisis. [Copyright &y& Elsevier]

Abstract: Increasing energy demands, predicted fossil fuels shortage in the near future, and environmental concerns such as the production of greenhouse gas carbon dioxide have motivated the search for alternative and cleaner energy sources. Biodiesel has received much attention in recent years and production of biodiesel from microalgae is a newly emerging field. Microalgae possess a high growth rate, utilize solar light, water and CO2 to convert these to sugars, from which macromolecules, such as lipids and triacylglycerols (TAGs) can be obtained making microalgae more photosynthetically efficient than oil crops. Microalgae are represented as a potential source of biomass, having great biodiversity and variability in their biochemical composition. This paper presents an overview on microalgae with particular emphasis as a source for biofuel and its other applications. Future research and development aspects regarding microalgae and microalgal fuel production are also discussed. [Copyright &y& Elsevier]

Abstract: Converting waste cooking oil into biofuel represents a three-win solution, dealing simultaneously with food security, pollution, and energy security. In this paper, we encode the policy documents of waste cooking oil refining biofuel in China based on content analysis, and explore the related policies from the two dimensions as basic policy tools and enterprises supply chain. Research indicates the weak institution coordination of policy issuing entities. Also, the findings show that tools of regulatory control and goal planning are overused. Policies of government procurement, outsourcing and biofuel consumption are relatively scarce. Generally, government focuses more on formulating policies from the strategic, administrative and regulatory aspects, while less on market-oriented initiatives as funding input and financial support. [Copyright &y& Elsevier]

Abstract: This paper primarily presents an overall review of the use of microalgae as a biofuel feedstock. Among the microalgae that have potential as biofuel feedstock, Chlorella, specifically, was thoroughly discussed because of its ability to adapt both to heterotrophic and phototrophic culture conditions. The lipid content and biomass productivity of microalgae can be up to 80% and 7.3g/l/d based on the dried weight of biomass, respectively, making microalgae an ideal candidate as a biofuel feedstock. The set-up of the system and the biomass productivity of microalgae cultivated in an open pond and a photobioreactor were also compared in this work. The effect of the culture condition is discussed based on the two-stage culture period. The issues that were discussed include the light condition and the CO2, DO and N supply. The microalgal productivities under heterotrophic and phototrophic culture conditions were also compared and highlighted in this work. The harvesting process and type of flocculants used to aid the harvesting were highlighted by considering the final yield of biomass. A new idea regarding how to harvest microalgae based on positive and negative charges was also proposed in this work. The extraction methods and solvents discussed were primarily for the conventional and newly invented techniques. Conversion processes such as transesterification and thermochemical processes were discussed, sketched in figures and summarized in tables. The cost–benefit analysis of heterotrophic culture and the cultivation system was highlighted at the end of this work. Other benefits of microalgae are also mentioned in this work to give further support for the use of microalgae as a feedstock for biofuel production. [Copyright &y& Elsevier]

Abstract: Considerable research is currently being devoted to seeking alternative fuels to comply with transportation needs while reducing the environmental impact of this sector. Within the transport activity sector, on road vehicles and agricultural machinery require around 2Mtoe energy in France. The anaerobic digestion of farm waste could roughly cover these needs. This paper aims to study the environmental and energy interest of this short power supply path. An ideal biogas production system has been built up from the average characteristics of current rural biogas plants in France. Pollutant emissions, energy demands and production are assessed for various scenarios in order to produce methane for dual fuel engines. Life cycle assessment (LCA) is used to evaluate the environmental impact of dual fuel agricultural machines, compared to diesel engines. The energy balance is always in disfavour of biogas fuel, whereas LCA energy indicators indicate a benefit for biogas production. This gap is related to the way in which the input of biomass energy is handled: in conventional biofuel LCA, this energy is not taken into account. A carbon balance is then presented to discuss the impact of biogas on climate change. Dual fuel engines were found to be interesting for their small impact. We also show, however, how the biogenic carbon assumption and the choice of allocation for the avoided methane emissions of anaerobic digestion are crucial in quantifying CO2 savings. Other environmental issues of biogas fuel were examined. Results indicate that are management and green electricity are the key points for a sustainable biogas fuel. It is concluded that biofuel environmental damage is reduced if energy needs during biofuel production are covered by the production process itself. As agricultural equipment is used during the biofuel production process, this implies that a high substitution rate should be used for this equipment. [Copyright &y& Elsevier]

Abstract: This paper examines biofuels from an economic perspective and evaluates the merits of promoting biofuel production in the context of the policies’ multiple objectives, life-cycle implications, pecuniary externalities, and other unintended consequences. The policy goals most often cited are to reduce fossil fuel use and to lower greenhouse gas emissions. But the presence of multiple objectives and various indirect effects complicates normative evaluation. To address some of these complicating factors, we look at a several combinations of policy alternatives that achieve the same set of incremental gains along the two primary targeted policy dimensions, making it possible to compare the costs and cost-effectiveness of each combination of policies. For example, when this approach is applied to U.S.-produced biofuels, they are found to be 14–31 times as costly as alternatives like raising the gas tax or promoting energy efficiency improvements. The analysis also finds the scale of the potential contributions of biofuels to be extremely small in both the U.S. and EU. Mandated U.S. corn ethanol production for 2025 reduces U.S. petroleum input use by 1.75% and would have negligible net effects on CO2 emissions; and although EU imports of Brazilian ethanol may look better given the high costs of other alternatives, this option is equivalent, at most, to a 1.20% reduction in EU, gasoline consumption. [Copyright &y& Elsevier]

Abstract: Today, energy crisis turn out to be a serious threat towards sustainability for developing countries since their energy demand is growing more rapidly than developed countries. On the other hand, fossil fuels cannot sustain anymore in the near future because of environmental impacts and depletion of the reserves. Malaysia is experiencing drastic growth in population and economy and requires exploring alternative energy sources to support its population and commercial energy demand. Biomass as the fourth largest energy resource in the world is abundant in the country. Malaysia is blessed with tropical and humid climate all year round which is a magnificent opportunity for fully exploiting agriculture and tropical forests potential. Since late 1990, the concept of waste-to-wealth had been promoted and became popular widely. This concept is based on unwanted wastes which are converted into valuable energy while reducing waste generated and increase the economy-efficiency mainly used for cooking, space heating and power generation. Currently, concerted efforts and various biomass energy programs are supporting by the government for development, demonstration and commercialization. This paper intent to present the current state and prospects of biomass utilization and strategies promoted for future developments in Malaysia. [Copyright &y& Elsevier]

Abstract: Australia is one of those countries that are considered rich and abundant in fossil fuel energy resources. It is important for Australia to regulate the use of conventional energy and attempt replacing these conventional energies with renewable energy (RE) resources. Renewable energy resources in Australia are widely categorised as solar energy, biomass, wave energy and wind energy. By increasing the utilisation of renewable energy resources the national contribution to world wide green house gases (GHG) emissions would be reduced, at the moment approximately 50% of Australia''s GHG emissions are contributed from electricity generation [Dicks, AL, Diniz da Costa, JC, Simpson A, McLellan B. Fuel cells, hydrogen and energy supply in Australia. Journal of Power Sources 2004;1:1–12] with a large proportion of the remaining emissions coming from transport and vehicular sectors. As Australia''s population, as well as that of the world, continues to grow and live increasingly energy dependant lives, the future of energy supply will grow. This paper investigates the potential of renewable resources in Australia at present and the magnitude of their present and future contributions to the national energy consumption. Conclusions will be drawn from the results of this investigative scan and recommendations will be proposed. [Copyright &y& Elsevier]

Abstract: This paper discusses the opportunity for substituting fossil fuels with biofuels in a Sahelian country, Burkina Faso. Bearing in mind the strong link between energy and development, and given the country''s heavy reliance on imported fossil fuels, our study showed that the overall economy (private and public companies and basic social services) and the State Budget could be seriously affected if no viable and local alternative is integrated into the national energy strategy. In view of local potential, it is recommended that adequate energy resources be sought in order to ensure sustainable socio-economic development. Biofuel opportunities are discussed taking into account technical, agronomic and land potentials in this country. Diversification of energy resources with biofuels would substantially reduce fuel imports in the short term, improve overall public finances, provide a chance to develop agriculture and provide benefits for the locals. However, if they are to generate development, biofuel projects need to be mindful of food security and economic incentives, and should be part of national agricultural strategies. [Copyright &y& Elsevier]

Abstract: Grass biomethane is a sustainable transport biofuel. It can meet the 60% greenhouse gas saving requirements (as compared to the replaced fossil fuel) specified in the EU Renewable Energy Directive, if allowance is made for carbon sequestration, green electricity is used and the vehicle is optimized for gaseous biomethane. The issue in this paper is the effect of the digester type on the overall emissions savings. Examining three digestion configurations; dry continuous (DCAD), wet continuous (WCAD), and a two phase system (SLBR-UASB), it was found that the reactor type can result in a variation of 15% in emissions savings. The system that as modeled produced most biogas, and fuelled a vehicle most distance, the two phase system (SLBR-UASB), was the least sustainable due to biogas losses in the dry batch step. The system as modeled which produced the least biogas (DCAD) was the most sustainable as the parasitic demands on the system were least. Optimal reactor design for sustainability criteria should maximize biogas production, while minimizing biogas losses and parasitic demands. [Copyright &y& Elsevier]

Abstract: Biomass is the major energy source in Ghana contributing about 64% of Ghana''s primary energy supply. In this paper, an assessment of biomass resources and biofuels production potential in Ghana is given. The broad areas of energy crops, agricultural crop residues, forest products residues, urban wastes and animal wastes are included. Animal wastes are limited to those produced by domesticated livestock. Agricultural residues included those generated from sugarcane, maize, rice, cocoa, oil palm, coconut, sorghum and millet processing. The urban category is subdivided into municipal solid waste, food waste, sewage sludge or bio-solids and waste grease. The availability of these types of biomass, together with a brief description of possible biomass conversion routes, sustainability measures, and current research and development activities in Ghana is given. It is concluded that a large availability of biomass in Ghana gives a great potential for biofuels production from these biomass resources. [Copyright &y& Elsevier]

Abstract: Environmental impacts associated with the use of fossil fuels, rising prices, potential limitations in supply and concerns about regional and national security are driving the development and use of biomass for bioenergy, biofuels and bioproducts. However, the use of biomass does not automatically imply that its production, conversion and use are sustainable. Conflicts between various ecosystem services (economic production of food, fodder and fuels, biodiversity, social and cultural values, etc.) that are provided by fertile land are increasing as well. Hence, a developed thinking on how to balance between these services is desirable. There is a significant amount of information available on biofuels and their sustainability. In this paper, different initiatives and sustainability criteria for biofuels are presented and assessed. 35 criteria were found in emerging sustainability assessment frameworks. The majority of 12 criteria were focused on environmental issues, 4 were social and only 1 was economic. Energy balance and greenhouse gas balance were perceived as especially critical, social criteria ranked generally low. Although being perceived as important, food security ranked very low. [Copyright &y& Elsevier]

Abstract: This paper surveys China''s renewable energy economy, focusing particularly on renewable energy laws and programs, the lessons that can be learnt from the current literature, and the implications of that literature. Gaps in the literature on China''s renewable energy economy include the need for more comprehensive econometric studies. The literature may also benefit from more collaboration between renewable energy economists and agricultural economists. [Copyright &y& Elsevier]

The novel coronavirus (COVID-19) is highly detrimental, and its death distribution peculiarity has severely affected people's health and the operations of businesses. COVID-19 has wholly undermined the global economy, including inflicting significant damage to the ever-emerging biomass supply chain; its sustainability is disintegrating due to the coronavirus. The biomass supply chain must be sustainable and robust enough to adapt to the evolving and fluctuating risks of the market due to the coronavirus or any potential future pandemics. However, no such study has been performed so far. To address this issue, investigating how COVID-19 influences a biomass supply chain is vital. This paper presents a dynamic risk assessment methodological framework to model biomass supply chain risks due to COVID-19. Using a dynamic Bayesian network (DBN) formalism, the impacts of COVID-19 on the performance of biomass supply chain risks have been studied. The proposed model has been applied to the biomass supply chain of a U.S.-based Mahoney Environmental® company in Washington, USA. The case study results show that it would take one year to recover from the maximum damage to the biomass supply chain due to COVID-19, while full recovery would require five years. Results indicate that biomass feedstock gate availability (FGA) is 2%, due to pandemic and lockdown conditions. Due to the availability of vaccination and gradual business reopenings, this availability increases to 92% in the second year. Results also indicate that the price of fossil-based fuel will gradually increase after one year of the pandemic; however, the market prices of fossil-based fuel will not revert to pre-coronavirus conditions even after nine years. K-fold cross-validation is used to validate the DBN. Results of validation indicate a model accuracy of 95%. It is concluded that the pandemic has caused risks to the sustainability of biomass feedstock, and the current study can help develop risk mitigation strategies. • Impact of coronavirus (COVID-19) on biomass supply chain is studied. • A case study of a US based biofuel company is presented. • A dynamic Bayesian network (DBN) model is developed to investigate the biomass supply chain's risk over ten years, considering pandemic and post-coronavirus situations. • The DBN model is able to predict risks and their behaviours under uncertainties. • Study identifies high preprocessing costs of biomass resource due to COVID-19. • Model validation indicates an accuracy of 95%. [ABSTRACT FROM AUTHOR]

Over the coming years, the world is projected to witness an upsurge in "drop-in" aviation biofuel production as part of the renewable energy and bioeconomy developments. This paper presents a comprehensive review of the current status of biojet fuel development and uptake in global commercial aviation industry, including state-of-the-art certified technologies (i.e. Fischer-Tropsch (FT); hydroprocessed esters and fatty acids (HEFA); alcohol-to-jet (ATJ); and hydroprocessing of fermented sugars (HFS)); potential feedstock that can be deployed; a comparison of techno-economic and environmental performances of biojet fuel production routes; airlines' commitment in promoting higher biofuel uptake; and global initiatives and policies. This review shows that the HEFA route using oil-based crops is best performing in terms of lowest production cost and greenhouse gas emissions, however it is in competition with the existing road transport biofuel market. Lignocellulosic biomass and waste feedstock should be promoted in view of replacing food/feed crops which have high indirect land use change emissions. Therefore, further improvement should be focused on FT, ATJ and HFS routes to enhance the cost effectiveness of biojet fuel production and promote commercialisation of these technologies. The selection of feedstock and technologies for SAF production should be justified based on production cost and environmental footprint, while avoiding competition with the existing road transport biofuel market. The shortcomings in the SAF policies such as blending mandate and multiplier in RED II should be addressed to reduce the negative impacts of feedstock competition between the road and aviation biofuel sectors and to meet the decarbonisation targets. • Waste and residue feedstock should be deployed for biojet fuel production. • Non-oil based routes require further improvement on cost competitiveness. • Imposing a blending mandate is more effective than voluntary approach. • Multi-stakeholder collaboration promotes uptake of sustainable aviation fuel. [ABSTRACT FROM AUTHOR]