Technoeconomic analysis of an integrated microalgae photobioreactor, biodiesel and biogas production facility

As fossil fuel prices increase and environmental concerns gain prominence, the development of alternative fuels from biomass has become more important. Biodiesel produced from microalgae is becoming an attractive alternative to share the role of petroleum. Currently it appears that the production of microalgal biodiesel is not economically viable in current environment because it costs more than conventional fuels. Therefore, a new concept is introduced in this article as an option to reduce the total production cost of microalgal biodiesel. The integration of biodiesel production system with methane production via anaerobic digestion is proved in improving the economics and sustainability of overall biodiesel stages. Anaerobic digestion of microalgae produces methane and further be converted to generate electricity. The generated electricity can surrogate the consumption of energy that require in microalgal cultivation, dewatering, extraction and transesterification process. From theoretical calculations, the electricity generated from methane is able to power all of the biodiesel production stages and will substantially reduce the cost of biodiesel production (33% reduction). The carbon emissions of biodiesel production systems are also reduced by approximately 75% when utilizing biogas electricity compared to when the electricity is otherwise purchased from the Victorian grid. The overall findings from this study indicate that the approach of digesting microalgal waste to produce biogas will make the production of biodiesel from algae more viable by reducing the overall cost of production per unit of biodiesel and hence enable biodiesel to be more competitive with existing fuels.     

Large-scale open pond algae biomass yield analysis in India: a case study

Global warming, depletion of fossil fuel and increasing demand for energy have led to the substantial interest in developing alternate energy sources, especially biodiesel. First generation biofuels produced from food crops and oil seeds are limited to achieve targets for biodiesel production. Second generation biofuel produced from non-food feed stock such as microalgae provides various potential advantages for biofuel production when compared with first generation biofuels. This paper investigates the possible use of microalgae for biofuel production on the selected potential sites in the country. Algal biomass and oil yield for the selected sites are predicted using the analytical method.     

Competitiveness,role, and impact of microalgal biodiesel in the global energy future

This paper examines the competitiveness, role, and impact of microalgal biodiesel in the 21st century using a global energy system model with a detailed technological representation. The major conclusions are the following. First, the competitiveness of microalgal biodiesel decreases as CO₂ stabilization constraints become more stringent. The share of microalgal biodiesel and renewable jet fuel produced from it in total global final energy consumption over the time horizon 2010–2100 is 5.1% in the case without CO₂ constraints compared with 3.9% and 0.7% in the case of CO₂ stabilization at 550 ppmv and 400 ppmv, respectively. This is because production and combustion of microalgal biodiesel release as much CO₂ as is captured from anthropogenic sources and assimilated by microalgae and because CO₂ prices raised by stringent CO₂ stabilization constraints make the economics of microalgal biodiesel unattractive. Second, the competitiveness of microalgal biodiesel is also greatly affected by microalgal production cost and microalgal lipid yield. Under a 400 ppmv CO₂ stabilization constraint, a 50% microalgal production cost decrease leads to increase in total global microalgal biodiesel production over the time horizon by a factor of 6.5, while a 50% microalgal lipid yield increase leads to increase in it by a factor of 4.5. Third, microalgal biodiesel plays an important role in satisfying the energy demand in the transport sector, thereby replacing petroleum products and Fischer–Tropsch synfuels. An increasing proportion of microalgal biodiesel is converted into renewable jet fuel over time to be used as a fuel for aircraft. Fourth, either without CO₂ constraints or under the 550 ppmv CO₂ stabilization constraint, the participation of microalgal biodiesel in the global energy market would have a large impact on the global energy supply and consumption structure. This is not only because of its substitution for other forms of final energy, but also because of the need to satisfy the demand for CO₂ for microalgal production.     

A comprehensive review on biodiesel as an alternative energy resource and its characteristics

As the fossil fuels are depleting day by day, there is a need to find out an alternative fuel to fulfill the energy demand of the world. Biodiesel is one of the best available resources that have come to the forefront recently. In this paper, a detailed review has been conducted to highlight different related aspects to biodiesel industry. These aspects include, biodiesel feedstocks, extraction and production methods, properties and qualities of biodiesel, problems and potential solutions of using vegetable oil, advantages and disadvantages of biodiesel, the economical viability and finally the future of biodiesel. The literature reviewed was selective and critical. Highly rated journals in scientific indexes were the preferred choice, although other non-indexed publications, such as Scientific Research and Essays or some internal reports from highly reputed organizations such as International Energy Agency (IEA), Energy Information Administration (EIA) and British Petroleum (BP) have also been cited. Based on the overview presented, it is clear that the search for beneficial biodiesel sources should focus on feedstocks that do not compete with food crops, do not lead to land-clearing and provide greenhouse-gas reductions. These feedstocks include non-edible oils such as Jatropha curcas and Calophyllum inophyllum, and more recently microalgae and genetically engineered plants such as poplar and switchgrass have emerged to be very promising feedstocks for biodiesel production.It has been found that feedstock alone represents more than 75% of the overall biodiesel production cost. Therefore, selecting the best feedstock is vital to ensure low production cost. It has also been found that the continuity in transesterification process is another choice to minimize the production cost. Biodiesel is currently not economically feasible, and more research and technological development are needed. Thus supporting policies are important to promote biodiesel research and make their prices competitive with other conventional sources of energy. Currently, biodiesel can be more effective if used as a complement to other energy sources.     

Microalgae for biodiesel production and other applications: A review

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.     

Comparison of palm oil, Jatropha curcas and Calophyllum inophyllum for biodiesel: A review

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.     

Net energy analysis of the production of biodiesel and biogas from the microalgae: Haematococcus pluvialis and Nannochloropsis

Microalgae have been proposed as possible alternative feedstocks for the production of biodiesel because of their high photosynthetic efficiency. The high energy input required for microalgal culture and oil extraction may negate this advantage, however. There is a need to determine whether microalgal biodiesel can deliver more energy than is required to produce it. In this work, net energy analysis was done on systems to produce biodiesel and biogas from two microalgae: Haematococcus pluvialis and Nannochloropsis. Even with very optimistic assumptions regarding the performance of processing units, the results show a large energy deficit for both systems, due mainly to the energy required to culture and dry the microalgae or to disrupt the cell. Some energy savings may be realized from eliminating the fertilizer by the use of wastewater or, in the case of H. pluvialis, recycling some of the algal biomass to eliminate the need for a photobioreactor, but these are insufficient to completely eliminate the deficit. Recommendations are made to develop wet extraction and transesterification technology to make microalgal biodiesel systems viable from an energy standpoint.     

Transesterification of marine macroalgae using microwave technology

Biodiesel is renewable and environmental friendly, with calori?c value equivalent to regular fossil fuel. This fuel can be produced from a variety of feedstocks, such as ?rst-generation biodiesel feedstock (corn, peanut, soybean), second generation (jatropha, animal fats, waste cooking oils, macroalgae), and third generation (microalgae). Among these feedstocks, biodiesel production from microalgae has drawn special attention for different reasons: they have high lipid content and high growth rates; they are tolerant to severe environmental conditions; they offer the possibility of sequester carbon dioxide from the ?ue gases; their harvesting and transportation are economical compared to other crops; and they have very high photosynthetic yields compared to other terrestrial plants. The advantage of using macroalgae recollected on the beaches as raw material is that allows to obtained energy from a residue.

Microwave-assisted extraction and transesteri?cation of microalgae is being researched as a solution for biodiesel production by its benefits, such as shorter reaction times and less amount of heat energy to obtain biodiesel. It is due to the fact that microwaves can easily penetrate through the cell wall structure to extract and transesterify the oils into biodiesel.

The aim of this research was to explore the possibility of carrying out the microwave-assisted transesterification of three marine macroalgae (brown and green). Different experimental runs were carried out with different process parameters such as macroalgae-to-methanol ratio, reaction time and catalyst concentrations. Based on the obtained results, the best conditions for microwave-assisted transesteri?cation reaction were macroalgae-to-methanol ratio of 1:15 (wt/vol), sodium hydroxide concentration of 2 wt% and reaction time of 3 min.     

Biofuels from microalgae—A review of technologies for production,processing, and extractions of biofuels and co-products

Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO₂, N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products.This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.     

A review on biodiesel production,combustion, emissions and performance

This article is a literature review on biodiesel production, combustion, performance and emissions. This study is based on the reports of about 130 scientists who published their results between 1980 and 2008. As the fossil fuels are depleting day by day, there is a need to find out an alternative fuel to fulfill the energy demand of the world. Biodiesel is one of the best available sources to fulfill the energy demand of the world. More than 350 oil-bearing crops identified, among which some only considered as potential alternative fuels for diesel engines. The scientists and researchers conducted tests by using different oils and their blends with diesel.A vast majority of the scientists reported that short-term engine tests using vegetable oils as fuels were very promising but the long-term test results showed higher carbon built up and lubricating oil contamination resulting in engine failure. They concluded that vegetable oils, either chemically altered or blended with diesel to prevent the engine failure. It was reported that the combustion characteristics of biodiesel are similar as diesel and blends were found shorter ignition delay, higher ignition temperature, higher ignition pressure and peak heat release. The engine power output was found to be equivalent to that of diesel fuel. In addition, it observed that the base catalysts are more effective than acid catalysts and enzymes.     

Technical aspects of production and analysis of biodiesel from used cooking oil—A review

The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of biodiesel fuel has made it more attractive in recent times. The cost of biodiesel, however, is the major hurdle to its commercialization in comparison to petroleum-based diesel fuel. The high cost is primarily due to the raw material, mostly neat vegetable oil. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, can affect the transesterification reaction and the biodiesel properties. This paper attempts to review various technological methods of biodiesel production from used cooking oil. The analytical methods for high quality biodiesel fuel from used cooking oil like GC, TLC, HPLC, GPC and TGA have also been summarized in this paper. In addition, the specifications provided by different countries are presented. The fuel properties of biodiesel fuel from used cooking oil were also reviewed and compared with those of conventional diesel fuel.     

A comprehensive review on pretreatment of microalgae for biogas production

Use of microalgal biomass for renewable energy production has gained considerable attention in the world due to increasing global energy demand and negative environmental impacts of nonrenewable fossil fuels. Anaerobic digestion is one of the renewable technologies that microalgal biomass is converted into biogas by anaerobic archea. One of the main drawbacks of using microalgal biomass for biogas production is that certain types of microalgae has rigid cell wall characteristics, which limits accessibility of anaerobic archea to microalgal intracellular organic matter during hydrolysis phase. This limitation lowers efficiency of biogas production from microalgal biomass. However, introducing pretreatment methods prior to anaerobic digestion provides disruption of rigid microalgal cell wall and improve biogas yields from microalgal biomass. The objective of this paper was to review current knowledge related to pretreatment methods applied prior to anaerobic digestion of microalgal biomass. Efficiency and applicability of pretreatment methods mainly depend on type of microalgae, cell wall characteristics, and cost and energy requirements during pretreatment process. In this review, various type of pretreatment methods applied to microalgal biomass was discussed in detail with background knowledge and literature studies in their potential on maximization of biogas yields and their cost effectiveness, which is important for large‐scale applications. In the view of current knowledge, it was concluded that each pretreatment method has a relative contribution to improvement in biogas production depending on the type of microalgae. However, energy and cost requirements are the main limitations for pretreatment. So, further studies should focus on reduction of cost and energy demand by introducing combined methods, novel chemicals, and on‐site or immobilized enzymes in pretreatment to increase feasibility of pretreatment prior to anaerobic digestion in industrial scale.     

Recent trends in biodiesel production from commonly used animal fats

Changes in climate due to the enormous amount of carbon dioxide emissions have really encouraged the development of energy sources that are renewable, sustainable, and eco‐friendly. The development of alternative energy sources can also be attributed to the rapid decrease in resources of fossil energy. Biodiesel has gained significant interest in recent years due to its fossil fuel–like properties and sustainable and eco‐friendly characteristics. However, most biodiesels are expensive because of the high cost of feedstock largely based on edible vegetable oil sources. The use of animal fats waste as cost effective feedstock in biodiesel production has gained considerable attention in recent years. Although, most studies regarding the use of animal wastes as feedstock in biodiesel production are still in the early stages, the advantages of this type of feedstock have been highlighted in the literature. However, most studies have not focus on the recent advances in the use of animal fats waste. The studies on the use of novel approach have been reported in isolation. Therefore, this current study attempts to highlight recent developments of the most commonly used animal fats waste in the production of biodiesel. In addition, emphasis was given to the most appropriate production technique, catalyst, energy requirement, and optimum reaction conditions.     

Quality analysis studies on biodiesel production of neochloris oleoabundans algae

The petroleum fuels play a major role in industry, agriculture, and transport besides meeting out many other basic human needs. However, fossil fuels are limited in quantity and are depleting day by day as the consumption is increasing very rapidly. Biodiesel is one such fuel in which there is a lot of hope. In the recent past, biodiesel received considerable attention as a renewable fuel. In India, it has not been possible to produce biodiesel from edible oils since the same is very scarce. Hence, the scope of opting to non-edible oils from plants as raw material for biodiesel production recently gained momentum. This paper presents the production of biodiesel from nonedible, Neochloris oleoabundans oil and its characterization. The studies were carried out on transesterification of oil with methanol, sodium hydroxide, and Sodium methoxide as catalyst for the production of biodiesel. The process parameters such as catalyst concentration, reaction time, and reaction temperature were optimized for the production of Neochloris oleoabundans oil biodiesel. The biodiesel yield of 95.15% was noticed at optimal process parameters.     

A review on microalgae,a versatile source for sustainable energy and materials

Increasing energy demands, predicted fossil fuels shortage in the near future, and environmental concerns due to the production of greenhouse gas carbon dioxide on their combustion have motivated the search for alternative ‘clean’ energy sources. Among many resources for this, microalgae have been found to be most promising due to their high production capacity of vegetable oils. They possess a high growth rate, need abundantly available solar light and CO₂, and thus are more photosynthetically efficient than oil crops. Also, they tolerate high concentration of salts allowing the use of any type of water for the agriculture and the possibility of production using innovative compact photobioreactors. In addition, microalgae are a potential source of biomass, which may have great biodiversity and consequent variability in their biochemical composition. This paper presents an overview on microalgae with particular emphasis as a source for energy (biofuel/electricity) and new materials. Critical issues involved in production of microalgae and their use, future R & D to overcome these, including the work initiated by the authors at Federal University of Paraná, UFPR, in Brazil are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Biodiesel production from oleaginous microorganisms

High energy prices, energy and environment security, concerns about petroleum supplies are drawing considerable attention to find a renewable biofuels. Biodiesel, a mixture of fatty acid methyl esters (FAMEs) derived from animal fats or vegetable oils, is rapidly moving towards the mainstream as an alternative source of energy. However, biodiesel derived from conventional petrol or from oilseeds or animal fat cannot meet realistic need, and can only be used for a small fraction of existing demand for transport fuels. In addition, expensive large acreages for sufficient production of oilseed crops or cost to feed animals are needed for raw oil production. Therefore, oleaginous microorganisms are available for substituting conventional oil in biodiesel production. Most of the oleaginous microorganisms like microalgae, bacillus, fungi and yeast are all available for biodiesel production. Regulation mechanism of oil accumulation in microorganism and approach of making microbial diesel economically competitive with petrodiesel are discussed in this review.     

Biodiesel production by microalgal biotechnology

Biodiesel has received much attention in recent years. Although numerous reports are available on the production of biodiesel from vegetable oils of terraneous oil-plants, such as soybean, sunflower and palm oils, the production of biodiesel from microalgae is a newly emerging field. Microalgal biotechnology appears to possess high potential for biodiesel production because a significant increase in lipid content of microalgae is now possible through heterotrophic cultivation and genetic engineering approaches. This paper provides an overview of the technologies in the production of biodiesel from microalgae, including the various modes of cultivation for the production of oil-rich microalgal biomass, as well as the subsequent downstream processing for biodiesel production. The advances and prospects of using microalgal biotechnology for biodiesel production are discussed.     

Microalgal biodiesel in China: Opportunities and challenges

With rapid economic development, energy consumption in China has tripled in the past 20 years, exceeding 2.8 billion tons of standard coal in 2008. The search for new green energy as substitutes for nonrenewable energy resources has become an urgent task. Biodiesel is one of the most important bioenergy sources. According to the Mid- and Long-term Development Plan for Renewable Energy in China, the consumption of biodiesel in China will reach 0.2 million tons in 2010 and 2.0 million tons in 2020. However, large-scale production of biodiesel is restricted by the limited sources of raw materials. Microalgal oil is a prospective raw material for biodiesel production. Development of technology for the production and commercialization of biodiesel from microalgae has become a hot topic in the field of bioenergy and CO₂ emission mitigation. Biodiesel from microalgae can be produced at laboratory-scale, but the cost is too high. Few studies on the commercialization of the technology of producing biodiesel from microalgae have been reported. In this review, recent progress on the research and development of biodiesel from microalgae that have resulted in scientific breakthroughs and innovation in engineering in China are introduced. The existing challenges are also discussed. Based on a detailed analysis, several novel strategies on commercial biodiesel production from microalgae are proposed.     

Dark fermentative biohydrogen production using pretreated Scenedesmus obliquus biomass under an integrated paradigm of biorefinery

In recent times, biohydrogen production from microalgal feedstock has garnered considerable research interests to sustainably replace the fossil fuels. The present work adapted an integrated approach of utilizing deoiled Scenedesmus obliquus biomass as feedstock for biohydrogen production and valorization of dark fermentation (DF) effluent via biomethanation. The microalgae was cultivated under different CO₂ concentration. CO₂-air sparging of 5% v/v supported maximum microalgal growth and carbohydrate production with CO₂ fixation ability of 727.7 mg L^?1 d^?1. Thereafter, lipid present in microalgae was extracted for biodiesel production and the deoiled microalgal biomass (DMB) was subjected to different pretreatment techniques to maximize the carbohydrate recovery and biohydrogen yield. Steam heating (121 °C) in coherence with H₂SO₄ (0.5 N) documented highest carbohydrate recovery of 87.5%. DF of acid-thermal pretreated DMB resulted in maximum H₂ yield of 97.6 mL g^?1 VS which was almost 10 times higher as compared to untreated DMB (9.8 mL g^?1 VS). Subsequent utilization of DF effluent in biomethanation process resulted in cumulative methane production of 1060 mL L^?1. The total substrate energy recovered from integrated biofuel production system was 30%. The present study envisages a microalgal biorefinery to produce biohydrogen via DF coupled with concomitant CO₂ sequestration.     

Necessity of biodiesel utilization as a source of renewable energy in Malaysia

In recent decades, the energy crisis and environmental issues have become a crucial problem. The rapid industrialization has lead humankind to deplete the fossil fuels and consequently the pollutant emissions have increased in the world. Many investigations have been done to find an alternative fuel to fulfill increasing energy demand. Recently, biodiesel has been introduced as an economical renewable and sustainable fuel which is cited as an environment-friendly resource. Around 350 oil-bearing crops were analyzed and some of them were capable to be considered as potential alternative fuels for diesel engines. These include virgin vegetable oils and waste vegetable oils. Rapeseed, jatropha, soybean, and palm oil are mentioned as the most common sources of biodiesel. Many countries have invested in biodiesel as an acceptable source of energy not only in research area but also in production and export. It has been proven that the biodiesel combustion characteristics are similar as petroleum. Higher ignition pressure and temperature, shorter ignition delay and higher peak release were reported in experimental combustion of biodiesel blends. Also, the efficiency of biodiesel base catalysts is more than enzymes and acid catalysts. This article is a literature review on necessity of biodiesel production as alternative fuel recourse in Malaysia and tries to illustrate the combustion characteristics and pollutant formation in biodiesel application.