Search

Abstract: Gradual depletion of fossil fuel has greatly enhanced the necessity to look for alternative fuel for automotive engine. In response to this, biodiesel is being considered as a promising solution with a number of technical advantages over conventional petroleum diesel. However, commercial use of biodiesel has been limited because of some drawbacks including corrosivity, instability of fuel properties, higher viscosity, etc. Stability of fuel properties is especially important to ensure expected engine performance as well as engine life. Most of the research papers available in public domain reported some concerns on the stability of biodiesel fuel properties. Scattered studies on different aspects often lead to confusions in understanding the adverse effects of different factors on the degradation of biodiesel. In this article, different factors that cause instability in biodiesel and their possible implications of different fuel properties have been reviewed. A special emphasis has been given to explain the possible mechanisms of biodiesel degradation. Possible remedies to improve the stability of biodiesel have also been included. Finally, some general conclusions concerning these problems are summarized and further scopes of study have been suggested. [Copyright &y& Elsevier]

Abstract: Energy crops constitute significant potential for meeting the future energy need worldwide. In addition, agricultural lands offer an alternative to the agriculture which is referred to as energy farming. The studies on energy crops in biofuel production show that they are quite an economical and environmentally beneficial way of sustainable energy production. Today most of the developed countries use staples such as corn, sugar beet, soybean, rapeseed, and wheat in order to obtain energy. Moreover, bioethanol is mostly produced from sugarcane and corn and biodiesel from oilseed plants. Therefore, these produced raw materials compete with food and feed production. Consequently, the use of those energy crops which are used as food products for biofuel production is an important issue which must be considered in terms of the current food safety. Some energy crops, such as miscanthus, switchgrass and sweet sorghum, that are called C4 crops, can grow with high biomass yield even in infertile land. Thus, these crops are used in energy farming – a new type of agriculture. Furthermore, C4-type crops possess the features of resistance to aridity, high photosynthetic yield and a high rate of CO2 capture when compared with C3 crops. In conclusion, C4 crops tend to produce more biomass than C3 crops. Therefore, these crops are investigated, focused on, and elaborated on in this paper. This study aims to present a comprehensive review on the production of biofuels from lignocellulosic agricultural products and promising energy crops. Thus, the energy crops to be used as raw materials for biofuels today and in the future are investigated. In addition, it is intended to highlight the energy crops used as staples by discussing them in detail for biofuel production. The energy crops which are promising in biofuel production, particularly non-staple miscanthus and sorghum, are presented in detail as they are non-food crops and have a high yield. Furthermore, the energy crops used as raw materials for bioenergy today and their potential are compared both worldwide and in Turkey. [Copyright &y& Elsevier]

Abstract: The demand for petroleum has been rising rapidly due to increasing industrialization and modernization. This economic development has led to a huge demand for energy, most of which is derived from fossil fuel. However, the limited reserve of fossil fuel has led many researchers to look for alternative fuels which can be produced from renewable feedstock. Increasing fossil fuel prices have prompted the global oil industry to look at biodiesel, which is from renewable energy sources. Biodiesel is produced from animal fats and vegetable oils and has become more attractive because it is more environmentally friendly and is obtained from renewable sources. Glycerol is the main by-product of biodiesel production; about 10% of the weight of biodiesel is generated in glycerol. The large amount of glycerol generated may become an environmental problem, since it cannot be disposed of in the environment. In this paper, an attempt has been made to review the different approaches and techniques used to produce glycerol (hydrolysis, transesterification, refining crude glycerol). The world biodiesel/glycerol production and consumption market, the current world glycerin and glycerol prices as well as the news trends for the use of glycerol mainly in Brazil market are analyzed. The technological production and physicochemical properties of glycerol are described, as is the characterization of crude glycerol obtained from different seed oil feedstock. Finally, a simple way to use glycerol in large amounts is combustion, which is an advantageous method as it does not require any purification. However, the combustion process of crude glycerol is not easy and there are technological difficulties. The news and mainly research about the combustion of glycerol was also addressed in this review. [Copyright &y& Elsevier]

Abstract: This paper assesses 13 different inputs for biodiesel production and shows that the highest cost currently associated with the processing of residual resources, as well as their small production scale, are compensated by their smaller procurement costs, by their immediate availability in the urban centers and by their larger potential for greenhouse gas emission reduction. Biodiesel production from residues can meet all technical international specifications, even the esterification process. Data Envelopment Analysis (DEA), the methodology used in this study, allows for the building of an efficiency index up through linear programming with multiple inputs and outputs, enabling the integration of sustainable development dimensions. The experts' conclusions were arrived at through restrictions on virtual weighting, with findings that allow the grading of alternatives. [Copyright &y& Elsevier]

Abstract: This paper aims at the assessment of the methods of production of biodiesel from different types of used cooking oil. Researches into the productive chain of this type of biofuel were performed in Brazil while several scientific studies approaching processes of pretreatment and transesterification of waste cooking oil were analyzed with their possible variations: alkaline catalysis, acid catalysis, enzymatic catalysis and non-catalytic conversion techniques, highlighting the main advantages and disadvantages of each analyzed route. The use of alkaline catalysts in transesterification is the most common technique employed by the industry, being the KOH the most recommended catalyst for the reaction with waste cooking oil. When water and acidity contents are high, pretreatment techniques and other types of catalysts such as solid acids are recommended. Moreover, the economic benefits provided by used cooking oil were analyzed, indicating reductions of up to 45% of direct production costs compared to virgin oils, even with the additional costs of the pretreatment. Finally, the availability of raw materials was estimated, indicating that the used cooking oil would have potential to supply up to 13% of the demand for biodiesel in Brazil. [Copyright &y& Elsevier]

Abstract: Microalgae have great potential as renewable fuel sources, but a dire need exists for high-level academic and industrial research into their growth and bioprocessing. New algae strains that efficiently use CO2 and wastes as nutrients, novel oil extraction methods, and industrial-scale designs for fuel production are imperative for long-term energy sustainability. A particular challenge to research in this field is the transition from pilot studies to industrial operations, which often exposes algae cells and their products to hostile environments, reducing yields. Hence, a need exists to integrate algae cell engineering with predictive bioprocess engineering to ensure economic and environmental feasibility and minimize the number of full-scale trials that fail. This review provides a brief overview of biofuel production from microalgal biomass. It highlights the most promising microalgae species for different types of fuel, the proper choice of photobioreactor and process parameters, product extraction techniques, and the main biofuel products. The main goal of this paper is to promote research into energetically- and environmentally-favorable technologies via the development of better algal strains and separation, extraction, and conversion methods. [Copyright &y& Elsevier]

Biodiesel is eco-friendly, less toxic and one of the most researched biofuels in recent years to reduce our reliance on fossil fuels and minimize emissions. The various problems associated with batch-type reactors are longer residence time, higher operating costs, and energy consumption with low production efficiency. Researchers are now focusing on continuous flow biodiesel production techniques to overcome problems in batch reactors. This paper highlights various reactors used in continuous flow biodiesel synthesis, catalyst mechanism, hybrid reactors technique and separation methods. Various continuous flow reactors used in biodiesel production have been discussed and the microreactor was intensively elaborated. Compared to traditional reactors, microreactor technology exhibits higher efficiency, improved mixing, high heat and mass transfer rates due to a high surface-area-to-volume ratio and short diffusion distance. The parameters that influence the liquid-liquid phase flow patterns in the microreactors include mixer type, channel size, internal configuration reaction time, reaction temperature, and alcohol to oil ratio. Post-treatment techniques help to improve the quality of the biodiesel and utilization of by-products has been discussed. The limitations and practical implications prevailing in the microreactors help improve the reactor techniques forward in large-scale production. Finally, the review addresses future directions in bridging the gap in current research on microreactors for better yield and high biodiesel quality. [Display omitted] • A review of the various continuous flow reactors used for biodiesel production was presented. • Biodiesel production using continuous-flow microreactors and their significance was intensively discussed. • Advances required to improve the improve mass transfer rate and conversion of biodiesel was presented. • The importance of the post-treatment techniques to improve the quality of biodiesel was briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Vegetable oils and animal fats are the most often used feedstock in biodiesel production; however, they are also used in food production, which results in increasing the feedstock price due to the competition. Therefore, alternative feedstock is required in biodiesel production. Heterotrophic microalgae are found capable of accumulating high lipid (up to 57% w/w). They can use complex carbons such as sweet sorghum and Jerusalem artichoke as nutrients to produce equivalent quantity oil as that of using glucose, which provides a cheap biodiesel production strategy. It was found that nanomaterials could stimulate microorganism metabolism, which suggested that nanomaterial addition in the cultivation could enhance lipid production of microalgae. Furthermore, the use of nanomaterials could improve the efficiency of the lipid extraction and even accomplish it without harming the microalgae. Nanomaterials such as CaO and MgO nanoparticles have been used as biocatalyst carriers or as heterogeneous catalyst in oil transesterification to biodiesel. In this paper, the factors that could impact on lipid accumulation of heterotrophic microalgae are critically reviewed; the advances on application of nanotechnology in microalgae lipid accumulation, extraction, and transesterification are addressed. [Copyright &y& Elsevier]

Abstract: Biodiesel has potential as a substitute for petroleum diesel because of the increasing worldwide concern for environmental sustainability and dwindling petroleum resources. Methanol has been the commonly used alcohol for biodiesel production. Compared with methanol, ethanol can be derived from sugar- and starch-based feedstocks and lignocellulosic biomass. Therefore, using ethanol as the acyl acceptor for biodiesel (fatty acid ethyl esters, FAEEs) production is drawing increasing interest in recent years. There are extensive studies using various approaches for the preparation of FAEEs and the properties of these fuels have also been explored. This paper reviews the state-of-the-art technologies for FAEE preparation. At the end, the fuel properties of FAEEs as well as the limitations and perspectives of biodiesel production with ethanol as the acyl acceptor are highlighted. [Copyright &y& Elsevier]

Abstract: With a deep concern over the energy shortage and climate change, biodiesel has become more attractive to governments globally. Xanthoceras sorbifolia Bunge, an endemic oilseed tree to China, has been identified as a major woody energy plant for biodiesel production and receives special support from Chinese governments for its development. This paper analyzes the opportunities and challenges for biodiesel production from X. sorbifolia in China. The biological characteristics, geographic distribution, site requirements, propagation, cultivation and productivity of this species are described. The information about the presence of various phytochemicals in different parts of the plant is summarized. As a multifunctional tree, it plays other important roles in addition to the oil production for biodiesel, having many potential uses such as soil and water conservation, land reclamation, carbon sink, landscaping, and productions of foods, fodders, medicines and industrial chemicals. The potential advantages and disadvantages of the biodiesel production from X. sorbifolia are outlined, and the needs for further research are recommended. The low fruit-setting rate and the small percentage of fine breeds result in a low yield, a high development cost, and a low economic efficiency of the biodiesel production, which is the development bottleneck of the biodiesel industry of X. sorbifolia presently. Integral valorization of the co-products such as leaves, branches, hulls, testa and kernel meals can make for the cost reduction and industrial production of the biodiesel from X. sorbifolia. [Copyright &y& Elsevier]

Abstract: Increasing energy demand and environment concerns have prompted an evolution of alternative fuel sources. As an alternative fuel source, biodiesel is attractive because it reduces engine emissions. However, biodiesel produces higher NO x emissions compared to ordinary diesel fuel. Previous researches have established many factors that cause biodiesel to produce elevated NO x emissions. This study reviews the impacts of biodiesel combustion on NO x emissions and their reduction approaches in diesel engines. The first part of this study recaps the NO x formation mechanisms for understanding the kinetics behind the NO x forming reactions. The second part describes the factors affecting on NO x emissions. This paper established that higher NO x emissions are produced for biodiesel combustion which influenced by several factors such as physicochemical properties and molecular structure of biodiesel, adiabatic flame temperature, ignition delay time, injection timing and engine load conditions etc. The final section discusses on the reduction of NO x emissions from biodiesel fuelled engines for both pre and post combustion techniques. The results of reduction approaches of the NO x emissions implies, exhaust gas recirculation (EGR) and retarded injection timing are effective as well as low cost techniques than others. Between these two techniques, EGR reduces the NO x emissions at 5–25% EGR rate adequately in biofuelled engine by controlling oxygen content and combustion peak temperature with slightly decreasing HC and CO emissions. However this technique shows few penalties on smoke and PM emissions as well as brake specific fuel consumption if not perfectly optimized. [Copyright &y& Elsevier]

Abstract: It is a good solution to produce biodiesel by using waste edible oils (WEO), such as waste cooking oils and used frying oils, due to its low cost, disposal problems and potential contamination. Therefore, WEO biodiesels has been gradually produced, and thus applied to study their effects on engine performances and emissions. However, few reviews about these studies have been published to assist understanding and popularization for WEO biodiesels so far. This paper attempts to cite and analyze highly rated journals in scientific indexes about combustion characteristics, engine power, economy, regulated emissions and non-regulated emissions of WEO biodiesels on diesel engine. The use of WEO biodiesels leads to the slight difference in combustion characteristics such as ignition delay, rate of pressure rise, peak pressure and heat release rate, and the substantial reduction in PM, HC and CO emissions accompanying with the imperceptible power loss, the increase in fuel consumption and NO x emission on conventional diesel engines with no or fewer modification, compared to diesel. Although the inconsistent conclusions have been made on CO2 emission of biodiesels from WEO, it reduces greatly from the view of the life cycle circulation of CO2. For non-regulated emissions, the reduction appears for PAH emissions but carbonyl compounds emissions have discordant results for WEO biodiesels. Therefore, WEO biodiesels have the similar combustion characteristics, engine performances and emissions to that of biodiesels from food-grade oils, and the blends of WEO biodiesel with small content by volume could replace the petroleum-based diesel fuel to help in controlling air pollution, encouraging the collection and recycling of waste edible oil to produce biodiesels and easing the pressure on scarce resources to a great extent without significantly sacrificing engine power, economy and emissions. [Copyright &y& Elsevier]

Abstract: Biodiesels are gaining more importance as a promising alternative energy resource. Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by its ignition and combustion behavior. This review article presents the literature review on ignition delay (ID), combustion and emission characteristics of biodiesel fueled diesel engine. More than hundred articles report which have been published mostly in the last decade are reviewed in this paper. The investigation results report that the combustion characteristics of bio fueled engine is slightly different from the engine running with petroleum diesel. Most of the investigation results have reported that as compared to diesel, biodiesel has early start of combustion (SOC) and shorter ID of between 1–5° and 0.25–1.0°, respectively. Higher cetane number (CN), lower compressibility and fatty acid composition of biodiesel have been identified as the main elements for early SOC and shorter ID. In addition, it is also found that, the heat release rate (HRR) of biodiesel is slightly lower than diesel owing to the lower calorific value, lower volatility, shorter ID and higher viscosity. [Copyright &y& Elsevier]

Abstract: Alarming situation of world energy stimulated the researchers to look for new sources of fuel, which must be renewable, locally available and environmentally benign. In this regard, the significance of biodiesel as technically and commercially viable alternative to fossil-diesel has led to intense research in the field. Biodiesel is made from different feedstock depending on the availability. This paper analyzes the performance and emission of biodiesel from different feedstock. The main advantage of biodiesel is that it potentially reduces the key pollutants, carbon monoxide, unburnt hydrocarbons and particulate matters. While several researchers have looked at the impact of biodiesel on these pollutants, only few publications discussed the effect of fatty acid composition on performance and emission characteristics. An attempt has been carried out to discuss the effect of biodiesel in terms of performance and emissions based upon composition and properties of the respective biodiesel. The results of the study show that different chemical compositions of biodiesel based upon their origin lead to variation in their properties and performance and emission characteristics. Biodiesel produced from saturated feedstock reduce NO x emission and resistive to oxidation but exhibit poor atomization. However, many further research needs to be carried out to understand the relationship between the type of biodiesel feedstock and performance and emission. [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: World energy demand is expected to increase due to the expanding urbanization, better living standards and increasing population. At a time when society is becoming increasingly aware of the declining reserves of fossil fuels beside the environmental concerns, it has become apparent that biodiesel is destined to make a substantial contribution to the future energy demands of the domestic and industrial economies. There are different potential feedstocks for biodiesel production. Non-edible vegetable oils which are known as the second generation feedstocks can be considered as promising substitutions for traditional edible food crops for the production of biodiesel. The use of non-edible plant oils is very significant because of the tremendous demand for edible oils as food source. Moreover, edible oils’ feedstock costs are far expensive to be used as fuel. Therefore, production of biodiesel from non-edible oils is an effective way to overcome all the associated problems with edible oils. However, the potential of converting non-edible oil into biodiesel must be well examined. This is because physical and chemical properties of biodiesel produced from any feedstock must comply with the limits of ASTM and DIN EN specifications for biodiesel fuels. This paper introduces non-edible vegetable oils to be used as biodiesel feedstocks. Several aspects related to these feedstocks have been reviewed from various recent publications. These aspects include overview of non-edible oil resources, advantages of non-edible oils, problems in exploitation of non-edible oils, fatty acid composition profiles (FAC) of various non-edible oils, oil extraction techniques, technologies of biodiesel production from non-edible oils, biodiesel standards and characterization, properties and characteristic of non-edible biodiesel and engine performance and emission production. As a conclusion, it has been found that there is a huge chance to produce biodiesel from non-edible oil sources and therefore it can boost the future production of biodiesel. [Copyright &y& Elsevier]

Abstract: Biodiesel is primarily obtained from the base catalyzed transesterification reaction of oils or fats. Biodiesel has become more attractive due to its characteristics of being bio-degradable, renewable and non-toxic. Recently biodiesel has been widely used as an alternative fuel. Biodiesel quality analysis has become very important because consistency and a higher quality are paramount to the success of its commercialization and market acceptance. Suitable and precise analytical methods are needed to meet this requirement. Some analytical techniques have been considered and applied in biodiesel analysis, such as Chromatography and Spectroscopy. Within the Spectroscopic technique, Infrared Spectroscopy has played an important role. Past reviews on analytical methods for biodiesel analysis were written by Knothe and Marcos Roberto Monteiro. In this paper, the author has discussed the developments in biodiesel quality analysis with IR technique. [Copyright &y& Elsevier]

Abstract: Transesterification is the most common method for producing biodiesel. Known as a suitable substitute to diesel fuel, the synthesis involves renewable sources as feedstock. Application of both organic and inorganic solvents in biodiesel production has been widely established. However, as the properties of conventional solvents are perpetually hazardous to human and environment, utilization of greener alternative is a better option. Among the various types of solvents available, ionic liquid seems prevalent. An ionic liquid is a combination of cations and anions, has low or negligible vapor pressure, and exists as liquid at temperature below 100°C. The prospect of ionic liquids as green solvents in chemical processes is increasing in recent years, especially in biodiesel synthesis. This paper highlighted the properties of ionic liquids that emphasized their versatility as solvents, and the use of switchable ionic liquids as green solvents is also presented. The roles of ionic liquids in biodiesel synthesis are discussed, focusing on their pertinent capability as solvents, particularly as catalysts for transesterification reaction. Since the cost of ionic liquid may be an issue, a brief discussion about the recyclability of ionic liquids is also included. [Copyright &y& Elsevier]

Abstract: Biodiesel is commonly produced from lipid feedstock, animal fats and waste cooking oil by transesterification reaction. Considering the depletion of fossil fuel, biodiesel is gaining more attention as a renewable and environmental friendly fuel. The rapid growth of biodiesel industry thereafter has raised concerns to many existing commercial biodiesel enterprises. The major issues like feedstock flexibility, yield productivity and environmental impact are always the challenges to the continuous growth of conventional biodiesel processing technology. The processing of biodiesel is greatly hinged on the rich scientific background and technology development for better process advancement. The present paper reviews various concerns raised from the commercial biodiesel processing technology. It also addresses some innovative process intensification (PI) technologies, which likely bring appropriate technological improvement for biodiesel production. [Copyright &y& Elsevier]

Abstract: The increasing energy demands along with the expected depletion of fossil fuels have promoted to search for alternative fuels that can be obtained from renewable energy resources. Biodiesel as a renewable energy resource has drawn the attention of many researchers and scientists because its immense potential to be part of a sustainable energy mix in near future. This report attempts to compile the findings on current global and Malaysian energy scenario, potential of biodiesel as a renewable energy source, biodiesel policies and standards, practicability of Jatropha curcas as a biodiesel source in Malaysia as well as impact of biodiesel from Jatropha curcas. Final part of this report also describes the development of biodiesel market in Malaysia. The paper found that Jatropha curcas is one of the cheapest biodiesel feedstock and it possesses the amicable fuel properties with higher oil contents compared to others. Being non edible oil seed feedstocks it will not affect food price and spur the food versus fuel dispute. Jatropha can be substituted significantly for oil imports. Jatropha biodiesel has potential to reduce GHG emission than diesel fuel and it can be used in diesel engine with similar performance of diesel fuel. Jatropha curcas has an immense contribution to develop rural livelihoods too. Finally biodiesel production from Jatropha is eco-friendly and offers many social and economical benefits for Malaysia and can play an increasingly significant role to fulfill the energy demand in Malaysia. [Copyright &y& Elsevier]

Abstract: Biodiesel is a good alternative fuel to petroleum diesel. It is produced through transesterification reaction between vegetable oil or animal fats and alcohol. The process faces various problems related to the immiscible nature of the reactants causing poor mass transfer rate. This drawback is responsible for long reaction time and low reaction rate leading to an energy intensive process. Process intensification through the use of active catalyst, pressure reactor, high temperature, high stirring rate or even non-conventional approaches such as supercritical method and Biox process often subjects to drawbacks with respect to energy consumption, product quality and reactants cost. This paper highlights recent development in the production of biodiesel under ultrasonic irradiation conditions. It handles the drawback of poor immiscibility between reactants as ultrasonic energy can emulsify the reactants to reduce the catalyst requirement, reaction time and reaction temperature. Ultrasonic energy also neglects the limitations in the use certain feed stocks. Fundamental aspects of the ultrasonic-assisted process using homogeneous and heterogeneous catalysts are reviewed. Recent achievement and future development in this technology in a batch and continuous process are also highlighted. [Copyright &y& Elsevier]

Abstract: In this paper, the fat content of insects is studied for its utilization in the production of biodiesel. The study has shown the great fat potential of insects, highlighting a large number of species with an ether extract higher than 25%, including a large number in excess of 30% and some even reaching levels close to or above 77%. Moreover, a review of the main criteria to be considered for the selection of insect species for biodiesel production is carried out. It was observed that the fat content varies widely between orders, species, and their stages of development – larva, prepupa, pupa, nymph or adult – with the larval stage being that at which the most fat is accumulated. Furthermore, variations in the fat content were observed within the same species due to factors such as origin (wild or bred in captivity) or type of diet. This last factor is one of the most important to take into account for the selection of insect species with the objective of using their fat in the production of biodiesel. The principal conclusion of this study is that insects, through the development of their life cycle, can be fed with agricultural, industrial or urban by-products in order to accumulate a large amount of fat with potentially excellent quality (fatty acids C16–18), for conversion into energy through biodiesel production. Moreover, the resulting protein can also be used as a protein source in animal feed. Therefore, insects are a renewable source of protein and energy. [Copyright &y& Elsevier]

Abstract: The environmental concern and availability of fuels are greatly affecting the trends of fuels for transportation vehicles. Biodiesel is one of the options as alternative transport fuel. This can be produced from straight vegetable oils (SVOs), oils extracted from various plant species and animal fats. Amongst many resources, availability and cost economy are the major factors affecting the large scale production of the biodiesels. The transesterification is one of the production processes for biodiesel, but incomplete esterification of all fatty acids in the starting material, lengthy purification methods such as water washing, relatively long reaction times, contamination and separation difficulties associated with co-production of glycerol and saponification of the starting material under certain reaction conditions are still being major challenges in the biodiesel production. Technological advancement and enhanced production methods are the demand of present time for large scale and sustainable production of biodiesel. In the present paper, comprehensive review on its production process, feed stock and its applications have been made. From many case studies it was concluded that engine performance with B20 biodiesel blends, and mineral diesel were found comparable. [Copyright &y& Elsevier]

Abstract: The enormous challenges faced in the search for suitable and profitable feedstocks to produce biodiesel cannot be over-emphasis. This paper has provided an overview of different catalysts used in processing different kinds of feedstocks for the production of biodiesel. Although the process of biodiesel production from refined feedstocks is less cumbersome and could provide biodiesel yield of more than 98%, but its product cost is high. Thus, the recent biodiesel production from low-quality feedstocks, though presents challenges but has equally provided biodiesel yield comparable to that obtained from refined feedstocks. Furthermore the physicochemical properties of biodiesel derived from low-quality feedstocks are discussed. Additionally economic evaluation of biodiesel from low-quality feedstocks is examined. The result showed that if less expensive feedstocks are used to produce biodiesel, a 25% reduction in cost production is possible. Thus making biodiesel price reasonably closed to the price of petro-diesel. [Copyright &y& Elsevier]

Abstract: In order to verify and solve the problem of NOx and PM emissions, it is necessary to directly observe the internal combustion chamber of a diesel engine. Many studies have been performed in recent years to verify the macroscopic and microscopic behavior of the injected fuel spray because observing it is not easy due to the difficulties of the experiment. Researchers have investigated the spray characteristics for various diesel injector nozzles over a wide range of temperatures and pressure, but there is lack of evaluation for the spray characteristics for biodiesel. At a time when rapid rise of fuel prices and depleting hydrocarbon resources of the world have forced us to look for alternative fuels biodiesel produced by transesterification of non-edible vegetable oils is promising to be an important additive/substitute to petro diesel. Biodiesel being an oxygenated and sulfur-free fuel leads to more complete combustion and lower emissions. But, the energy content or net calorific value of biodiesel is less than that of diesel fuel; also it has higher viscosity and density, than diesel fuel. A considerable improvement in these properties can be obtained by mixing diesel and biodiesel and then using the blends. Biodiesel and biodiesel/petro diesel blends, with their higher lubricity levels, are increasingly being utilized as an alternative. Present paper analyzed the correlation of injection parameters that will affect the spray characteristics of biodiesel. Observations for analyzing the effect of injection parameters on spray cone angle, break up length and fuel penetration were made. Finally the performance and emissions tests were studied. Atomization and vaporization of fuel are greatly influenced by viscosity and density of fuel and these properties are temperature dependent. Thus fuel inlet temperature plays a very important role in fuel atomization process. At higher temperature viscosity of fuel decreases which enhances the atomization of biofuels. [Copyright &y& Elsevier]

Abstract: The present investigation is undertaken to investigate prospect of seeds of a locally available tree (koroch) for biodiesel production. The middle-size, evergreen koroch tree with spreading branches are available in Assam. The characteristics of koroch biodiesel and engine performance fueled by koroch biodiesel are also analyzed reviewing similar results available in the literature so as to ascertain its status. Twelve number of different tree seed oils, reported earlier, are considered for making the present comparative assessment. Though transesterification has been the common process for converting tree seed oil into biodiesel, as evidenced from the literature consulted in this study, but there have been variations of the chemical processes. Variations of the transesterification are attributed to (i) types of catalysis viz., acid (H2SO4) or base (KOH, NaOH, and NaOCH3), (ii) reaction temperature, (iii) molar ratio, (iv) nature of reaction viz., single stage or multi-stage. The outputs of the reaction have also been found varying in terms of yield as well as quality. Quality of biodiesel, however, was found to influence by the nature of feedstock. The assessment of quality parameters was made either by ASTM D 6751 or EN 14214 standards. The major fuel properties such as calorific value, kinematic viscosity, cetane number and cloud point of the reference biodiesel (koroch biodiesel) are compared with the properties of five biodiesel obtained from non-edible tree seed (karanja, mahua, polonga, jatropha and rubber seed) and then ranked them in order of desirable property. No single biodiesel type could be found at top rank with reference to more than one property. With regards to viscosity, except rubber seed biodiesel, all other biodiesels (karanja, mahua, polonga, jatropha and koroch) fulfilled the ASTM D 6751 (1.9–6cSt) as well as EN14214 (3.5–5) standards. Koroch biodiesel ranks 3rd, 3rd and 6th in case of kinematic viscosity, cetane number and calorific value amongst the biodiesel types considered for the present study. Cloud point of koroch, polanga, mahua, rubber, karanja and jatropha biodiesels are 4, 13.2, 5, 4, 12 and 4°C. Further, properties of biodiesel were found to have influencing correlation with the fatty acid characteristics of the feedstock. Therefore, biodiesel with desirable properties could be expected form optimum mixing of different feedstock. Eleven number of different engine performance results pertaining to uses of biodiesel are also reviewed in this paper. Varying test conditions with reference to fuel types and blends, engine size and loading pattern are discussed. Engine performance results of koroch biodiesel were then compared with five similar tree-based biodiesel. It is observed that tree seed oil with more unsaturated fatty acids exhibits lower thermal efficiency compared to biodiesel having more saturated acids. [Copyright &y& Elsevier]

Abstract: In the present paper state-of-the art and perspectives of ultrasound-assisted (UA) biodiesel production from different oil-bearing materials using acid, base and enzyme catalysts are critically discussed. The ultrasound action in biodiesel production is primarily based on the emulsification of the immiscible liquid reactants by microturbulence generated by radial motion of cavitation bubbles and the physical changes on the surface texture of the solid catalysts generating new active surface area. The importance of ultrasound characteristics and other process variables for the biodiesel yield and the reaction rate is focused on. UA transesterification is compared with other techniques for biodiesel production. Several different developing methods reducing the biodiesel production costs such as the optimization of process factors, the development of the process kinetic models, the use of phase transfer catalysts, the application of the continuous process, the design of novel types of ultrasonic reactors and the in situ ultrasound application in transesterification of oily feedstocks are also discussed. [Copyright &y& Elsevier]

Abstract: Jatropha, a non-edible oil seed yielding plant has been identified by the Government of India to produce biodiesel under National Biodiesel Mission. Failure of National Biodiesel Mission Phase-I requires critical analysis of all the possible facts related to its long-term sustainability. Present work identifies important sustainability issues related to promotion of Jatropha biodiesel in India. These sustainability issues have been regrouped in four major categories: technological, environmental, economic and social. This paper attempts to explore various sustainability issues taking into account the recent Indian experiences with possible government support/initiatives for successful adoption of Jatropha biodiesel in Indian scenario. [Copyright &y& Elsevier]

Abstract: Biofuels are derived from biomass using biochemical, thermochemical, and physical and chemical extraction processes. Waste oils from animal and vegetable sources continue to be important biomass feedstock due to the potential benefits over petroleum and some of the virgin vegetable oil based fuels. In this paper, the chemical, thermal, and physical properties of biofuels derived from virgin and waste sources are reviewed. In addition, the processes used for recovering bio-oils from animal fats (beef tallow, lard, and poultry waste) and greases, and purification and refining of bio-oils are discussed as well as the resulting performance as a fuel. Particular focus will be on production of biofuels from fish waste. The potential for biofuel from fish waste is a function of the location and size of the processing plant, type of fuel requirements, and characteristics of the fish waste. [Copyright &y& Elsevier]

Abstract: The waste eggs and mollusk shells are found to be the richest sources of calcium carbonate and have been utilized for various purposes after proper treatments. When calcined at a proper temperature calcium carbonate converts into CaO, which is a metal oxide. Researchers have found that the CaO prepared from the waste shells can be used as catalyst in biodiesel production process. Utilization of waste shells as a source of CaO not only gives an opportunity to use it as catalyst but also adds value to the waste generated. In this paper a brief discussion with recent development on biodiesel production using waste shell derived solid oxide as catalyst is presented. [Copyright &y& Elsevier]

Abstract: Transportation has dominated global fuel consumption and greenhouse gas emissions have risen in an alarming rate. Gasoline and diesel consumption for road transport have a faster growing rate than other sector and the trend appeared to be rapidly moving upwards in the near future. This has caused much concern in many countries including Malaysia to improve the sustainable energy of this sector. The focus of this paper is to analyze the trends of energy pattern and emission of road transport in Malaysia. On top of that, the review of prospective policies such as fuel economy standards and fuel switching to natural gas as well as biodiesel are summarized in this study. The study found that there is an urgent need to adopt suitable energy policy to balance the energy demand and reduce emission in this sector. This study serves as a guideline for further investigation and research in order to implement and improve the transportation sector. [Copyright &y& Elsevier]

Abstract: Membranes processes for the production and refining of biodiesel are being increasingly reported. Membrane technology has attracted the interest of researchers for its ability to provide high purity and quality biodiesel fuel besides its remarkable biodiesel yields. Membranes have numerous numbers of useful properties such as resistance to mechanical, chemical and thermal stress, high available surface area per unit volume, high selectivity, and ability to control the components contact between the two phases makes them potential. These properties have made them to be potential candidates for both upstream and downstream biodiesel production and refining applications. In this regards, this paper critically examined the production and refining of biodiesel fuel via membrane technology. [Copyright &y& Elsevier]

Abstract: Energy is a basic requirement for economic development. Every sector of Indian economy-agriculture, industry transport, commercial and domestic needs input of energy. The economic development plans implemented since independence have necessarily required increasing amount of energy. As a result consumption of energy in all forms has been steadily rising all over the country. This growing consumption of energy has also resulted in the country becoming increasingly dependent on fossil fuels such as coal, oil and gas. Rising prices of oil and gas and potential shortage in future lead to concern about the security of energy supply needed to sustain our economic growth. Increased use of fossil fuels also causes environmental problems both locally and globally. In view of the fast depletion of fossil fuel, the search for alternative fuels has become inevitable, looking at huge demand of diesel for transportation sector, captive power generation and agricultural sector, the biodiesel is being viewed a substitute of diesel. The vegetable oils, fats, grease are the source of feed stocks for the production of biodiesel. Biodiesel is an engine fuel that is created by chemically reacting fatty acids and alcohol. This usually means combining vegetable oil with methanol in the presence of a catalyst (usually sodium hydroxide). Biodiesel is much more suitable for use as an engine fuel than straight vegetable oil for a number of reasons, the most notable one being its lower viscosity. The aim of the present paper is to focus on the work done in the area of biodiesel and also the impact analysis of biodiesel on engine performance. [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: Energy is fundamental to the quality of life in the earth. Meeting the growing demand for energy sustainably is one of the major challenges of the 21st century. Indonesia is a developing country and the world''s fourth most populous nation. Total annual energy consumption increased from 300,147GWh in 1980, 625,500GWh in 1990, 1,123,928 in 2000 and to 1,490,892 in 2009 at an average annual increase of 2.9%. Presently, fossil-fuel-based energies are the major sources of energy in Indonesia. During the last 12 years, Indonesia has recorded the most severe reduction in fossil fuel supplies in the entire Asia-Pacific region. This reduction has stimulated promoting the usage of renewable energy resources capable of simultaneously balancing economic and social development with environmental protection. Biodiesel is an alternative and environmentally friendly fuel that will participate in increasing renewable energy supply. Jatropha curcas is one of biodiesel resources that offer immediate and sustained greenhouse gas advantages over other biodiesel resources. Globally, J. curcas has created an interest for researchers because it is non-edible oil, does not create a food versus fuel conflict and can be used to produce biodiesel with same or better performance results when testing in diesel engines. The present study is concerned with the prospect of biodiesel produced from J. curcas in Indonesia. The first part gives a summary and overview of energy resources and consumption in the country, second part discusses the potential of biodiesel as a powerful renewable energy resource and third part investigates the potential of J. curcas as a feedstock for biodiesel in Indonesia. The final part discusses the development of biodiesel market in Indonesia. The paper found out that the production of biodiesel from J. curcas offers many social, economical and environmental benefits for the country and can play a great role to solve the problem of energy crisis in Indonesia. [Copyright &y& Elsevier]

Abstract: The world today is faced with serious global warming and environmental pollution. Besides, fossil fuel will become rare and faces serious shortage in the near future. This has triggered the awareness to find alternative energy as their sustainable energy sources. Biodiesel as a cleaner renewable fuel has been considered as the best substitution for diesel fuel due to it being used in any compression ignition engine without any modification. The main advantages of using biodiesel are its renewability and better quality of exhaust gas emissions. This paper reviews the production, performance and emission of palm oil, Jatropha curcas and Calophyllum inophyllum biodiesel. Palm oil is one of the most efficient oil bearing crops in terms of oil yield, land utilization, efficiency and productivity. However, competition between edible oil sources as food with fuel makes edible oil not an ideal feedstock for biodiesel production. Therefore, attention is shifted to non-edible oil like Jatropha curcas and Calophyllum inophyllum. Calophyllum inophyllum oil can be transesterified and being considered as a potential biodiesel fuel. Compared to Palm oil and Jatropha biodiesel industry, biodiesel from Calophyllum inophyllum is still in a nascent state. Therefore, long term endurance research and tribological studies need to be carried out before Calophyllum inophyllum oil base biodiesel can become an alternative fuel in future. [Copyright &y& Elsevier]

Abstract: The demand for petroleum has risen rapidly due to increasing industrialization and modernization of the world. This economic development has led to a huge demand for energy, where the major part of that energy is derived from fossil sources such as petroleum, coal and natural gas. However, the limited reserve of fossil fuel has drawn the attention of many researchers to look for alternative fuels which can be produced from renewable feedstock. Biodiesel has become more attractive because of its environmental benefits and it is obtained from renewable resources. There are four primary methods to make biodiesel: blending, microemulsion, pyrolysis and transesterification. The most commonly used method is the transesterification of triglycerides (vegetable oil and animal fats) with alcohol in the presence of a catalyst. There is a growing interest in using Jatropha curcas L. oil as the feedstock for biodiesel production because it is non-edible and thus does not compromise the edible oils, which are mainly used for food consumption. Non-edible oils are not suitable for human consumption because of the presence of toxic components. Further, J. curcas L. seed has a high content of oil and the biodiesel produced has similar properties to that of petroleum-based diesel. In this paper, an attempt has been made to review the different approaches and techniques used to generate biodiesel from Jatropha curcas oil. The main factors affecting the biodiesel yield, for example the molar ratio of alcohol to oil, catalyst concentration, reaction temperature and reaction time are discussed. Lastly, the environmental considerations and economic aspects of biodiesel are also addressed. [Copyright &y& Elsevier]

Abstract: The introduction of biofuels is one of the objectives of the European Union. For this reason, measures to promote the production and consumption of this product have been implemented, such as tax exemptions, fixing a minimum amount of mixture or the introduction of public transport that consume biofuels. In this paper, we test different factors that can affect the introduction of biodiesel in the Spanish gasoline market. These factors are mainly the level of local competition, technical difficulties and local government action. Empirical evidence shows that a higher level of competition, more buses that consume biodiesel and a lower adjustment costs increase significantly the probability of sell biodiesel at service stations. These results show how the promotion of competition and public procurement of vehicles can improve the commercialization of biofuels. [Copyright &y& Elsevier]

Abstract: Extensive research is being conducted all over the world to produce fuels from renewable biomass. Biodiesel, a renewable liquid fuel produced from lipid sources, is one of the most attractive among the options explored for alternative energy sources. However, 70–80% of the overall biodiesel production cost is associated with raw materials cost. Municipal sewage sludge is readily available at no cost. It contains various lipids and hence it is a promising raw material for biodiesel production. Lipids can be initially extracted from the sludge. Subsequently, the extracted lipid is converted to biodiesel by esterification and/or transesterification reaction. Biodiesel is also produced by in situ transesterification of dried sludge. This paper reviews the various lipid extraction techniques and biodiesel production processes from municipal wastewater sludge. [ABSTRACT FROM AUTHOR]

Abstract: Petro diplomacy has played its role in last few decades and that makes energy security a major concern worldwide. Rapid climate change and environmental protection is another vital issue to be addressed in recent energy policies. So an alternative carbon neutral transport fuel is a must in new sustainable energy mix. Biodiesel has immense potentiality to be a part of a sustainable energy mix. In this energy scenario, Brazil''s success is a role model in utilizing its agro-industry for reducing poverty, greenhouse gas emission and petro-dependency simultaneously. Brazil commercialized bioethanol in mass scale by introducing flexible fuel vehicles in market. This dedicated engine idea moralizes a new concept of dedicated biodiesel engine vehicles for Malaysia and Indonesia. Southeast Asian countries, i.e. Malaysia and Indonesia is the largest producer as well as exporter of palm oil. Growing at highest yield rate among other biodiesel feedstock, palm based biodiesel is a top exported product for this region. This paper will quantify the prospects of a dedicated biodiesel engine vehicle for Malaysia and Indonesia that will initiate palm based biodiesel in fuel supply chain by leapfrogging the barriers of biodiesel utilization by boosting local automobile industry simultaneously. This article will also review on energy scenario of Malaysia and Indonesia and their renewable energy policies and challenges for coming decades. [Copyright &y& Elsevier]

Abstract: The use of inedible vegetable oils as an alternative fuel for diesel engine is accelerated by the energy crisis due to depletion of resources and increased environmental problems including the great need for edible oil as food and the reduction of biodiesel production cost, etc. Of a lot of inedible vegetable oils which can be exploited for substitute fuel as diesel fuel, seven vegetable oils, i.e., jatropha, karanja, mahua, linseed, rubber seed, cottonseed and neem oils were selected for discussion in this review paper. The application of jatropha oil as a liquid fuel for CI engine can be classified with neat jatropha oil, engine modifications such as preheating, and dual fuelling, and fuel modifications such as jatropha oil blends with other fuels, mostly with diesel fuel, biodiesel, biodiesel blends and degumming. Therefore, jatropha oil is a leading candidate for the commercialization of non-edible vegetable oils. There exists a big difference in the fuel properties of seven inedible vegetable oils and its biodiesels considered in this review. It is clear from this review that biodiesel generally causes an increase in NOx emission and a decrease in HC, CO and PM emissions compared to diesel. It was reported that a diesel engine without any modification would run successfully on a blend of 20% vegetable oil and 80% diesel fuel without damage to engine parts. This trend can be applied to the biodiesel blends even though particular biodiesel shows 40% blend. In addition, the blends of biodiesel and diesel can replace the diesel fuel up to 10% by volume for running common rail direct injection system without any durability problems. [Copyright &y& Elsevier]

Abstract: As the environment degrades at an alarming rate, there have been steady calls by most governments following international energy policies for the use of biofuels. One of the biofuels whose use is rapidly expanding is biodiesel. One of the economical sources for biodiesel production which doubles in the reduction of liquid waste and the subsequent burden of sewage treatment is used cooking oil (UCO). However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. This paper attempts to collect and analyze published works mainly in scientific journals about the engine performance, combustion and emissions characteristics of UCO biodiesel on diesel engine. Overall, the engine performance of the UCO biodiesel and its blends was only marginally poorer compared to diesel. From the standpoint of emissions, NOx emissions were slightly higher while un-burnt hydrocarbon (UBHC) emissions were lower for UCO biodiesel when compares to diesel fuel. There were no noticeable differences between UCO biodiesel and fresh oil biodiesel as their engine performances, combustion and emissions characteristics bear a close resemblance. This is probably more closely related to the oxygenated nature of biodiesel which is almost constant for every biodiesel (biodiesel has some level of oxygen bound to its chemical structure) and also to its higher viscosity and lower calorific value, which have a major bearing on spray formation and initial combustion. [Copyright &y& Elsevier]

Abstract: The present global economy downturn affects every corner of the world including the vehicular fuel industry. This paper highlights some of the perspectives for the biodiesel industry to thrive as an alternative fuel, while discussing benefits and limitations of biodiesel. This includes the improvement of the conversion technology to achieve a sustainable process at cheaper cost, environmentally benign and cleaner emissions, diversification of products derived from glycerol, and policy and government incentives. More specifically, an overview is given on making the production process more economical by developing high conversion and low cost catalysts from renewable sources, and utilizing waste oil as feedstock. Further emphasis is given on the need for public education and awareness for the use and benefits of biodiesel, while promoting policies that will not only endorse the industry, but also promote effective land management. [Copyright &y& Elsevier]

Abstract: Energy plants play an important role in the development of bioenergy. In the world, there are many kinds of energy plants, but they are not utilized sufficiently. In the current paper, we discussed the situation of the research and development of traditional energy plants and some new energy plants in the world. At the same time, we focused on the distribution of some special energy plants and discussed their advantages in China. At last, we provided some suggestions for developing global energy plant field. [Copyright &y& Elsevier]

Abstract: Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO2, wastewater treatment, in human health, as food additive, and for aquaculture. [Copyright &y& Elsevier]

Abstract: The world is confronted with the twin crises of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of fossil fuels have led to a reduction in petroleum reserves. Petroleum based fuels are obtained from limited reserves. These finite reserves are highly concentrated in certain region of the world. Therefore, those countries not having these resources are facing a foreign exchange crisis, mainly due to the import of crude petroleum oil. Hence it is necessary to look for alternative fuels, which can be produced from materials available within the country. Although vegetative oils can be fuel for diesel engines, but their high viscosities, low volatilities and poor cold flow properties have led to the investigation of its various derivatives. Among the different possible sources, fatty acid methyl esters, known as Biodiesel fuel derived from triglycerides (vegetable oil and animal fates) by transesterification with methanol, present the promising alternative substitute to diesel fuels and have received the most attention now a day. The main advantages of using Biodiesel are its renewability, better quality exhaust gas emission, its biodegradability and the organic carbon present in it is photosynthetic in origin. It does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the green house effect. This paper reviews the source of production and characterization of vegetable oils and their methyl ester as the substitute of the petroleum fuel and future possibilities of Biodiesel production. [Copyright &y& Elsevier]

Abstract: Research on alternative fuel for the vehemently growing number of automotivesis intensified due to environmental reasons rather than turmoil in energy price and supply. From the policy and steps to emphasis the use of biofuel by governments all around the world, this can be comprehended that biofuel have placed itself as a number one substitute for fossil fuels. These phenomena made Southeast Asia a prominent exporter of biodiesel. But thrust in biodiesel production from oilseeds of palm and Jatropha curcas in Malaysia, Indonesia and Thailand is seriously threatening environmental harmony. This paper focuses on this critical issue of biodiesels environmental impacts, policy, standardization of this region as well as on the emission of biodiesel in automotive uses. To draw a bottom line on feasibilities of different feedstock of biodiesel, a critical analysis on oilseed yield rate, land use, engine emissions and oxidation stability is reviewed. Palm oil based biodiesel is clearly ahead in all these aspects of feasibility, except in the case of NO x where it lags from conventional petro diesel. [Copyright &y& Elsevier]

Abstract: Energy is essential and vital for development, and the global economy literally runs on energy. The use of fossil fuels as energy is now widely accepted as unsustainable due to depleting resources and also due to the accumulation of greenhouse gases in the environment. Renewable and carbon neutral biodiesel are necessary for environmental and economic sustainability. Biodiesel demand is constantly increasing as the reservoir of fossil fuel are depleting. Unfortunately biodiesel produced from oil crop, waste cooking oil and animal fats are not able to replace fossil fuel. The viability of the first generation biofuels production is however questionable because of the conflict with food supply. Production of biodiesel using microalgae biomass appears to be a viable alternative. The oil productivity of many microalgae exceeds the best producing oil crops. Microalgae are photosynthetic microorganisms which convert sunlight, water and CO2 to sugars, from which macromolecules, such as lipids and triacylglycerols (TAGs) can be obtained. These TAGs are the promising and sustainable feedstock for biodiesel production. Microalgal biorefinery approach can be used to reduce the cost of making microalgal biodiesel. Microalgal-based carbon sequestration technologies cover the cost of carbon capture and sequestration. The present paper is an attempt to review the potential of microalgal biodiesel in comparison to the agricultural crops and its prospects in India. [Copyright &y& Elsevier]

Abstract: Greece is a country in which biomass can play an important role in achieving the 2010 national target of 20% electricity production from Renewable Energy Sources (RES) Residues from traditional agricultural activities, but also the cultivation of new energy crops, can lead to a high level of availability and utilization of biomass energy products in Greece. In order for biomass to make a substantial contribution to the 2010 national target, set by the EU RES Directive 2001/77, as well as the corresponding 2020 target, to be set by the upcoming RES Framework Directive, a national policy plan for biomass and biofuels has to be formulated. This plan will assess the available biomass quantities and the potential and routes, by which this biomass can be converted to final energy products. The aim of the present paper is to discuss the current situation and prospects of biomass availability and exploitation in Greece and to develop a coherent and reliable methodology, in order to assess the conversion of the country’ s biomass potential into useful energy products. [Copyright &y& Elsevier]

Abstract: The introduction of biomass driven energy products like bioethanol, biodiesel, Combined Heat and Power production or solid biofuels is vital for achieving the targets set from the EU for the year 2010 (20% electricity production from RES). However, in order to reach these targets, a policy plan has to be formed concerning the conversion of biomass. The aim of this paper is to examine the logistics involved in the exploitation of already available or new biomass resources and to analyse various scenarios for the economic feasibility of the use of biomass and biofuels in Greece. [Copyright &y& Elsevier]