Commercial algae production facilities employ both open and closed cultivation systems. Each of these has advantages and disadvantages, but both require high capital input (Pienkos and Damns 2009). Open ponds are much more cheaper than closed systems because it demands relatively high capital and O&M costs associated with installation and operation of PBRs (Benemann 2012; Buford et al. 2012).

Lower costs and the possibility to scale up to several hectares make open ponds the main choice for algae commercial production (Benemann 2012). However, open pond cultures suffer from many limitations that can disrupt algal productiv­ity during unexpected environmental events. Another challenge for this system includes having access to an adequate supply of water for growth due to continu­ing loss of water through evaporation. Therefore, open ponds must be in a geo­graphic setting that has a fairly near source of water and a relatively flat terrain to avoid costly earthworks (Buford et al. 2012). Moreover, the open systems are susceptible to wind-born biological agents that can affect the cultivation, such as grazers, infectious fungi, lytic bacteria, viruses, other algae, and also lower tem­peratures in colder climates (Benemann 2012).

These open pond limitations stimulate PBRs development; however, only a few commercial plants use closed PBRs systems, mainly due to high costs as men­tioned before. Nowadays, according to Benemann (2012), microalgae cannot be grown in PBRs for commodities and are not even successful for high-value prod­ucts. However, PBRs can be used for seed culture production, though only for ~0.1 % of the biomass. Closed PBRs are significantly more expensive to construct, but have not been engineered to the extent of other reactors in commercial prac­tice, and so there may be opportunities for significant cost reductions.

Neither open ponds nor closed PBRs are mature technologies. Therefore, until large-scale systems are built and operated over a number of years, many uncer­tainties will remain. Cultivation issues for both open and closed systems, such as reactor construction materials, mixing, optimal cultivation scale, heating/cool — ing, evaporation, O2 build-up, and CO2 administration, have been considered and explored to some degree, but more definitive answers await detailed and expansive scale-up evaluations (Pienkos and Darzins 2009).

Concerning the various algal species and strains, they vary from study to study, depending on location and culture techniques. For that reason, it is not yet possible to predict what species or strain will be the best suited for commercial biofuel pro­duction, but it is most likely that it will differ from case to case, depending on the location, cultivation techniques chosen, processing technologies available, nutri­ents source, local climacteric conditions, and among other potential factors.

The cost of producing biodiesel depends on a number of factors, including the feedstock used in the process (i. e., the production cost of biomass), the capi­tal and operating costs of the production plant, the current value and sale of by­products, and the yield and quality of the fuel and by-products. Table 8 provides total and unit production costs of a representative European biodiesel plant (Italy) using rapeseed oil as feedstock (2010), which is a good example that includes the average characteristics of Italian plants, on the base of the information collected through firm survey (Finco 2012). The plan has capacity for 150,000 tons and pro­duces 150,000 tons of biodiesel.

Table 8 shows that the major economic factor to consider for input costs of bio­diesel production is the feedstock, which is about 80 % of the total production cost. This means that the market trend commodities prices highly influence the result of the biodiesel industry. In particular, feedstock costs can vary significantly from region to region due to their availability and market fluctuations, which can also make biodiesel production costs vary over time. Vegetable oils prices have changed significantly in the last 5 years. The prices have been rather stable until end of 2006, while from 2007 to 2008, they are more than doubled, declining again in 2009 reaching the 2006 level. In the second semester of 2010, the price registered another increase followed by a slight fall in 2012 (OECD-FAO 2012).

Table 9 shows the net margin of our representative plant. Nowadays, our plant perceives a negative economic result because revenues do not cover production costs. This result is mainly driven by the biodiesel price that is fixed by the refiner­ies and it is not connected with the production costs.

There are two components that influence the value of biodiesel: the diesel price on Platts and a premium price. The premium is determined by the refinery indus­try, and it depends on the vegetable oils price and the contractual power of the biodiesel plant. Technically, the premium price should correspond to the difference between the production costs and the diesel price on Platts, which biodiesel pro­ducers widely call the ‘business margin.’

However, according to the data from biodiesel plants, the premium price per­ceived corresponds to approximately 65 % of the ‘business margin.’ Moreover, this percentage depends on the policies adopted by the Governments, such as tax excise reductions or subsidies.

It is important to underline that biodiesel plants use a blend of vegetable oils and, consequently, the price can probably be lower than the rapeseed oil price that was used in the Table 9. Taking this into account, the results present an accurate representation of the Italian biodiesel industry.

However, the increased price of vegetables oil, the economic crisis, and policy changes at European level had negative impact on biodiesel production. For exam­ple, in Italy, the reduced tax exemption in 2009 and the subsequent abolition has diminished the profitability of the biodiesel plant realizing losses.

Lastly, the third attribute refers to the specificity of the assets involved in the trans­action. Assets are specific if their return depends on the continuity of a specific transaction. The more specific the asset, the greater the agents’ dependence on achieving the negotiation and therefore the greater the loss from an opportunistic behavior by one of the parties.

Williamson (1985) also proposes classifying the different ways a given transac­tion is performed, starting with the spot market, continuing with long-term con­tracts and concluding with the hierarchy (a single firm securing the transaction in question). If the asset specificity is null, the TCs are negligible, requiring no con­trol over the transaction; therefore, the spot market would be more efficient than other organizational forms. If, instead, the asset specificity is high, the costs asso­ciated with breaching the contract will be high, which would imply greater control over the transactions.

Also according to Williamson (1981), asset specificity is the most important critical dimension, as it is related to the type of investment. Thus, after perform­ing the specific investment, the seller and the buyer will operate in a bilateral exchange relationship for a considerable period of time (irreversibility cost). Williamson (1991a, b) discriminates six types of asset specificity:

a. locational: those whose application in a given transaction generates cost sav­ings in transport and storage, meaning specific returns to these productive units;

b. physical: those more suitable for a specific purpose (e. g., specific inputs for the production of a specific product);

c. human: related to the use of specialized human capital for an activity. This type of specificity is related to accumulated knowledge by the continuous execution of a particular activity;

d. dedicated: specific assets for a given transaction (e. g., to service a specific customer);

e. brand: refers to capital—not physical or human—manifested in a company’s brand, which is particularly relevant in the franchising world; and

f. temporal: refers to the value of the assets related to the period when the trans­action is processed. Thus, this asset becomes especially relevant in the case of negotiating perishable products.

According to Azevedo (2000), as it is not possible to determine a relationship that contains all eventualities, in some cases, renegotiation is inevitable. However, as an opportunistic behavior is a possibility, this renegotiation is subject to one of the parties taking advantage of the gains, which in turn results in losses to the other party. Thus, in economic transactions, based on the issue of opportunism, one side could try to take advantage of the other due to the impotence of predicting future events. Hence, agents often have to resort to safeguard contracts, which in turn contribute to increase some TCs.

There are some forms reported in the literature that enable controlling the prob­lems of post-contractual opportunism, namely increase the resources to monitor transactions, reduce information asymmetry, and adopt contractual incentives rewarding the agents’ compliance or good performance. The vertical integra­tion itself can eliminate conflict of interest, especially in transactions between an organization and its suppliers, reducing TC, though this integration could increase operating costs (Bonfim 2011).

On account of the intrinsically qualitative competitive process, the literature generally does not address the governance structures and the theory of competi­tiveness. This supposes, mistakenly, that the coordination of supply chains occurs efficiently or that more efficient structures through mechanisms associated with competitive rivalry are used (Farina 1999).

Coutinho and Ferraz (1995) pointed out that strategies are the basis of the dynamics of competitiveness, which seek to expand and renew the companies’ capacity required by the standards of competition (or “rules of the game”) in the market they are embedded.

Buainain et al. (2007) deem that competitiveness will only be achieved by including practices that encourage cooperation between the economic agents of a supply chain, including the government. According to the authors, considering that a company’s competitiveness is linked to the system it is inserted in could mean significantly changing the way such company views and manages its business. Thus, the authors emphasize the importance of vertical and horizontal manage­ment within a system to gain competitiveness. According to Buainain et al. (2007), a serious problem is the lack of works and experiences that report the problems of internal management in the family farmers’ network, as well as the relationship between them and their customers and suppliers.

Thus, competitiveness is reflected by these companies’ greater or lesser ability to adopt governance structures that reduce TC, enable greater integration with the agricultural production, and set conditions for systemic competitiveness (Batalha and Souza Filho 2009).

Quality control of the final product requires a large and varied number of chemi­cal analyses to evaluate the physical and chemical parameters in comparison with quality standards, usually established by regulatory legislation. Table 7 shows the specifications and analytical methods for the quality control of ethanol, an impor­tant Brazilian biofuel.

These data highlight the large number of techniques required to ensure ethanol quality, from classical techniques (volumetry, gravimetry, and direct potentiometry) to instrumental techniques (ion chromatography, GC-flame ionization detector, and AAS). The method for each analytical technique needs to be rigorously and systematically applied in order to enable accurate comparison between samples and to accurately assess the quality of the sample.

Figure 8 shows a flowchart for the use of AAS for quality control of ethanol. AAS is a rapid technique for the determination of the presence and concentration of several metals and some nonmetals. Nevertheless, preparation steps require attention because this step will release the analyte into the solution to be meas­ured. If not all of the species is released into the solution, inaccurate results will be obtained. The analytical result could be obtained as a concentration (mg kg-1 or mg L-1) or as a mass percentage in a certain volume (% m/v), depending on the individual’s interest or standard regulation.

Ahmad Zuhairi Abdullah, Shazia Sultana, Steven Lim and Mushtaq Ahmad

Abstract The potential application of acidic HZSM-5 and AlSBA-15 materials for catalytic degradation of high-density polyethylene (HDPE) into liquid hydrocarbon fuels was investigated using a tubular batch reactor. The reaction was carried out at various catalyst loadings between 5 and 15 % with 1:1, 2:1, and 3:1 HZSM-5 to AlSBA-15 ratios. The catalysts exhibited remarkable catalytic activity with conver­sions into liquid light hydrocarbons of up to 25 %. The gaseous product distribution showed a wide spectrum of hydrocarbons (Ci-C5) while the most predominant prod­ucts were C3 and C4 (47 and 40 %, respectively). Meanwhile, the liquid products were mostly in the range of C8-C25 depending on the reaction parameters and the amount produced decreased with increasing carbon number. Thus, catalytic degrada­tion of HDPE was a promising route for obtaining valuable fuels and petrochemicals from waste polymers. It required relatively low degradation temperatures to obtain liquid hydrocarbons with boiling points within that of gasoline range. At the same time, it could reduce the environmental problems caused by waste polymers.

Keywords High-density polyethylene • HZSM-5 • ALSBA-15 • Catalytic degradation • Hydrocarbon fuel

1 Introduction

In recent decades, plastic materials consumption has undergone a significant growth. According to an estimate, the global production and consumption of plas­tics have increased by about 10 % annually. At the same time, synthetic plastics

A. Z. Abdullah • S. Sultana (*) • S. Lim

School of Chemical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia e-mail: shaziaflora@hotmail. com

M. Ahmad

Biofuel Laboratory, Quaid-i-Azam University, Islamabad 45320, Pakistan

A. Domingos Padula et al. (eds.), Liquid Biofuels: Emergence, Development and Prospects, Lecture Notes in Energy 27, DOI: 10.1007/978-1-4471-6482-1_13, © Springer-Verlag London 2014

recycling has gained considerable attention all over the world due to the serious environmental problems caused by waste plastics and resources needed for man­ufacturing of such huge quantity of plastic materials. There are several methods practiced currently for degradation and disposal of high-density polyethylene (HDPE) such as landfill, thermal degradation, and incineration. However, all of these methods have not gained social acceptance for disposal of the waste mate­rial (Lee et al. 2002). The disposal is also currently becoming legally restricted because of a decrease in landfill availability, cost increase, and strong pollution concerns such as emissions of various combustion products.

Recycling of plastics should be projected to minimize the pollution. It has lower energy demand to support the process to offer high energy conservation while at the same time enhancing the efficiency of the process. Plastics recycling technolo­gies have been historically divided into four general types. Primary and secondary recycling processes involve the processing of waste/scrap materials into a product with characteristics similar to and different from those of original product, respec­tively. Tertiary recycling involves the production of basic chemicals and fuels from plastics waste/scrap as part of the municipal waste stream or as a segregated waste. Meanwhile, quaternary recycling process retrieves the energy content of waste/ scrap plastics by burning or incineration. Although the primary and secondary recy­cling processes are the most common being applied in the society, tertiary recycling and quaternary recycling have been regarded as more sustainable (Garforth et al. 1997). In contrast to landfill, thermal, and incineration methods used for degrada­tion of HDPE, chemical recycling using catalysts has emerged as a potentially inter­esting alternative. It can achieve degradation of plastic wastes for conversion into a variety of useful products, mainly as liquid fuels and raw chemical feedstock (Lee et al. 2002). In this regards, catalytic degradation using materials such as zeolites is considered to be suitable due to their unique pore diameter. These materials seem to be especially useable as catalyst supports for waste polymer degradation.

Generally, zeolites are aluminosilicate members of the family of microporous solids known as ‘molecular sieves’ and an ‘open’ structure that can accommodate a wide variety of cations. Meanwhile, mesoporous silicates such as MCM-41 and SBA-15 are porous silicates with huge surface areas (normally >1,000 m2/g), large pore sizes (2 nm < size < 20 nm), and ordered arrays of cylindrical mesopores with very regular pore morphology (Garforth et al. 1997).

In recent years, several researchers have reported the synthesis of a new class of porous materials which are supposed to combine the properties of both zeolites and ordered mesoporous aluminosilicates (Trong et al. 2001). Some examples of mesoporous materials that have been investigated in the past include MCM-41, KFS-16, and SAPO-37 (Jalil 2002; Marcilla et al. 2002; Miskolczi et al. 2005; Sakata et al. 2002). In continuing the efforts to degrade the HDPE waste into useful products such as liquid fuel, this study has been initiated. The objective of the research is the use of a laboratory tubular batch reactor to study: (i) the potential application of HZSM-5 and AlSBA-15 as acidic microporous and mesoporous catalysts for degradation of HDPE, (ii) the activ­ity of these catalysts and their effects under various operating conditions on product dis­tribution and selectivity, and (iii) to enhance the potential benefit of catalytic polymer recycling for industrial application in the future.

Biomass components mainly include lignocellulose, extractives, lipids, pro­teins, simple sugars, starches, H2O, hydrocarbons, ash, and other compounds (Kumar et al. 2009). Lignocellulosic biomass chemically consists of three main fractions: (1) cellulose (CH1.67Oo.83), (2) hemicellulose (CH1.64Oo.78), and (3) lignin (C1oH11O35). Cellulose is a polymer of glucose (a C6 sugar), which can be used to produce glucose monomers for fermentation to, for example, bioethanol. Hemicellulose is a copolymer of different C5 and C6 sugars including, for exam­ple, xylose, mannose, and glucose, depending on the type of biomass. Lignin is a branched polymer of aromatic compounds. The cellulose present in lignocellulosic biomass is resistant to hydrolysis. Therefore, to produce bioethanol or biobutanol from lignocellulosic biomass via biochemical route, it is essential that the biomass is pretreated in order to enable hydrolysis of the cellulose into sugars. Different pretreatment technologies have been developed (steam explosion, treatment with acids or bases, etc.) (Table 3), but the common purpose of these technologies is to break open the lignocellulosic structure. The primary goal of feedstock improve­ment should be to enhance the quality and efficiency of the pretreatment process, which would necessarily involve pretreatment efficiency and enzyme efficacy.

Data on the effects of reaction temperature on degradation of HDPE into various products using HZSM-5 (80) catalyst are shown in Table 3 while Table 4 presents the yields of degradation products using AlSBA-15 catalyst. It is clear that gen­erally the yield of volatile products increased with increasing reaction tempera­ture. It was well noted that by increasing the temperature, cracking probability was increased to result in higher yield of volatile products. At higher tempera­ture, the reaction was generally accelerated, and the accessibility of the reaction products resulting from interaction with external active sites and the reactant was improved. Thus, cracking reactions to give smaller molecular-sized sub­stances were improved. On other hand, the small internal pores of the HZSM-5 and AlSBA-15 catalysts could create hindrance toward the formation of liquid

Fig. 4 Effects of different catalysts on liquid products yield at 623 K with 10 % catalyst loading

products with relatively larger molecular sizes. The effect was more severe in the case of zeolite catalyst with internal pores in the micropore size range. However, it was also noted that the HZSM-5 (Si/Al = 80) catalyst had better capability to con­vert liquid products into gaseous products especially at high temperatures. Similar observations have been reported in literature (Mastral et al. 2006). For exam­ple, it was found that the liquid yield decreased with increasing temperature and higher temperature evidently caused decreases in boiling points of liquid products (Hernandez et al. 2006).

Findings made in this study were in good agreement with those reported by Mastral et al. (2006). They found that zeolitic materials were suitable to be used in

Fig. 5 Effects of reaction temperature on gas products yield by 10 % loading of HZSM-5(80) catalyst

catalytic degradation of polyethylene due to their acidity and structural suitability. As observed in this study, the highest gas yield was achieved by increasing the experi­mental temperature from 350 to 400 °C. Our results regarding the effects of tempera­ture on AlSBA-15 catalyst were also in good agreement with those of Sinfronio et al. (2006) who used Al-MCM-41 as the mesoporous catalyst. Based on these observa­tions, it could be concluded that the most suitable temperature range for maximum liquid fuel yield using HZSM-5 catalyst was 350 °C while it was 400 °C for AlSBA — 15 catalyst. However, higher coke deposition could sometimes correspond to the increasing reaction temperatures, and formation of waxy compound might prevent the accurate calculation of the yield of liquid and gaseous products.

Data regarding the effect of reaction temperature on the gaseous product yield using HZSM-5(80) catalyst are presented in Fig. 5. It is shown that 500 °C gave the most uniform products distribution with highest composition showed by C3 (34.5 %) and the lowest by C5 (11.2 %). By carrying out the reaction at 400 °C, remarkable reduction on the C1 while at the same time an increase in the propor­tion of carbon chain C5 was observed.

In order to compare the effect of temperature when a mesoporous catalyst was used, similar experimental run was carried out using AlSBA-15 catalyst. Figure 6 presents data that were obtained using the mesoporous catalyst. In this case, 350 °C showed the highest gaseous products yield with the highest composition showed by C4 while for the other two reactions, i. e., 400 and 500 °C, C3 predominated. Generally, temperature does not have dominant effects on the gaseous products dis­tribution. However, the difference in gaseous products distribution was significant when comparing results obtained with microporous HZSM-5 (80) and mesoporous AlSBA-15 catalysts. AlSBA-15 catalyst under same 10 % catalyst loading did not produce detectable C1 gas products. This mesoporous catalyst also led to increases in C5 (11.6 and 12.7 %) as compare to those of HZSM-5 microporous catalyst (4.4 and 7.0 %) for the reaction temperatures of 350 and 400 °C, respectively.

However, degradation of liquid products using HZSM-5 (80) showed a decreas­ing trend for increasing carbon chain from C8 to C25+. As shown in Fig. 7, the highest proportion of liquid products for all four reaction temperatures was in

Fig. 6 Effects of reaction temperature on gas products yield by 10 % loading of AlSBA-15 catalyst

Fig. 7 Effects of reaction temperature on liquid products yield by 10 % loading of HZSM-5 (80) catalyst

the carbon chain range of C8-C12. The lowest proportion of carbon chain range was the heaviest carbon chain, i. e., C25+ for all reaction temperatures studied. Increasing reaction temperature had the tendency to produce higher amount of shorter carbon chain molecules while simultaneously reducing the longer carbon chain molecules in the products mixture.

Figure 8 presents the data obtained using AlSBA-15 catalyst under the effect of varying temperatures. Generally, the results showed similar downward trend as observed in the case of using HZSM-5 (80) catalyst. The highest proportion was recorded by carbon chain range of C8-C12 for all three reaction tempera­tures. The second highest composition was recorded by the carbon chain range of C13-C16. This composition also dropped steadily as the reaction temperature increased. The lowest fraction of carbon chain range for the overall liquid prod­uct was C25+. By comparing the effect of varying reaction temperatures to both microporous HZSM-5 (80) and mesoporous AlSBA-15 catalysts, it was concluded that generally liquid degradation products for AlSBA-15 consisted of shorter

carbon chain range molecules. This could be seen for carbon ranges of C8-C12 and Сіз-Сі6 at 350 °C. AlSBA-15 catalyst produced nearly 78.2 % of overall liquid composition while it was only around 63.5 % for HZSM-5(80) catalyst.

The microalgae are photosynthetic organisms can grow in a wide variety of environments and conditions, including freshwater, salty, and brackish water (Benemann 2012). Their mechanism of photosynthesis is similar to higher plants, with the difference that the conversion of solar energy is generally more efficient because of their simplified cellular structure and more efficient access to water, CO2, and other nutrients.

Its uniqueness that separates them from other microorganisms is due to presence of chlo­rophyll and having photosynthetic ability in a single algal cell, therefore allowing easy operation for biomass generation and effective genetic and metabolic research in a much shorter time period than conventional plants (Singh and Sharma 2012).

In addition, the cultivation requirements are quite small, as most species only need water, CO2, and some essential nutrients such as nitrates, phosphates, and potas­sium, without needing the use of pesticides or fertilizers (Groom et al. 2008; Singh and Sharma 2012). Microalgae can produce lipids, proteins, and carbohydrates in large amounts over short periods of time. For these reasons, microalgae are capa­ble of producing 30 times as much oil per unit of land area compared to terrestrial oilseed (Sheehan et al. 1998). And these oil can be processed into both biofuels and valuable coproducts (Singh and Sharma 2012).

The microalgae cultivation can be heterotrophic or autotrophic. The hetero­trophic method is a biochemical conversion that relies on input feedstock derived from an upstream photosynthetic source. This approach uses closed bioreactor systems in a biochemical conversion process without light inputs. This dark fer­mentation process is based on the consumption of simple organic carbon com­pounds, such as sugars or acetate. The cultivation of algae using cellulosic sugars produced from wood and agricultural wastes or purpose-grown energy crops is an area of active research and development (Buford et al. 2012).

In the other hand, the autotrophic cultivation requires only inorganic com­pounds such as CO2, salts, and a source of light energy for their growth. This photosynthetic conversion involves two main methods: open ponds and closed photobioreactors (PBRs). The biomass produced in these autotrophic processes includes lipids that can be converted to fuels (Brennan and Owende 2010; Buford et al. 2012).

According to Benemann (2012), algae have been essentially produced in open ponds with the main strains currently being cultivated are Spirulina, Chlorella, Dunaliella, and Haematococcus. Most designs include mixing systems that use paddle wheels and carbonation techniques to supply and transfer CO2 (in-ground carbonation pit, bubble covers, and in-pound sumps1).

Microalgae are also grown in tanks and small-scale PBRs, in hundreds of dif­ferent systems around the world, producing from small amounts to huge sums of

http://www. powerplantccs. com/ccs/cap/fut/alg/alg_carbonation. html.

biomass annually. In this closed autotrophic approach, algae grow with sunlight or artificial lighting (Benemann 2012; Buford et al. 2012). Different types of PBRs have been designed and developed for cultivating algae that can be horizontal, vertical, tubular, flat, etc. (Benemann 2012; Singh and Sharma 2012). Each of these PBRs has their own advantages and disadvantages. Several studies are being developed which may overcome their limitations in the years to come (Singh and Sharma 2012).

Quality control of the final product requires a large and varied number of chemi­cal analyses to evaluate the physical and chemical parameters in comparison with quality standards, usually established by regulatory legislation. Table 7 shows the specifications and analytical methods for the quality control of ethanol, an impor­tant Brazilian biofuel.

These data highlight the large number of techniques required to ensure ethanol quality, from classical techniques (volumetry, gravimetry, and direct potentiometry) to instrumental techniques (ion chromatography, GC-flame ionization detector, and AAS). The method for each analytical technique needs to be rigorously and systematically applied in order to enable accurate comparison between samples and to accurately assess the quality of the sample.

Figure 8 shows a flowchart for the use of AAS for quality control of ethanol. AAS is a rapid technique for the determination of the presence and concentration of several metals and some nonmetals. Nevertheless, preparation steps require attention because this step will release the analyte into the solution to be meas­ured. If not all of the species is released into the solution, inaccurate results will be obtained. The analytical result could be obtained as a concentration (mg kg-1 or mg L-1) or as a mass percentage in a certain volume (% m/v), depending on the individual’s interest or standard regulation.

Although several challenges remain in the trail toward algae biofuels commercialization and its adoption as a biofuel, as seen so far, an increasing number of companies and policy makers seem to believe the rewards outweigh the risks. Thus, the expectation pathway for algae-based biofuels remains uncertain.

Theoretically, microalgae have been shown to be a potential source to produce biodiesel because of their many advantages as a sustainable feedstock for biodiesel production compared to other feedstocks (Ahmad et al. 2011). Nevertheless, not only more innovations are still needed for the development of technologies that reduce costs while increasing the yields of production (Singh and Gu 2010), but it is also required a comprehensive set of policies to assist the development of micro­algae technology.

In the management area, it is extremely important in the early phases of this prom­ising industry, to deliberate new business models that look at the bioenergy poten­tial of algae through the transportation fuels market, as well as production of other higher-value products so as to make the economics practicable (Singh and Gu 2010).

2 Conclusion

The continued use of fossil fuels for energetic purposes is gradually becoming clearer to the society that is unsustainable. Innovative technologies and sources of energy must be developed to replace fossil fuels. In this context, biofuels play a vital role in meeting the energy needs of human beings. There is reason to believe they will continue to do so in the future albeit in a different manner. The basic economic motivation for biofuels is that they are a convenient, low-priced, domes­tically producible and a substitute for oil. However, alternative sources of biofuel derived from terrestrial crops such as sugarcane, soybeans, maize, and rapeseed inflict a lot of pressure on the global food markets, contribute to water scarcity, and precipitate the destruction of forests. Besides that, many countries cannot grow most of the terrestrial crops due to climate factors or lack of fertile cultiva­tion areas for energetic purposes. In this context, algal biofuels can really make a contribution for the future world sustainability.

In the presented chapter, it is clear that algae are now being intensively researched as a potential biofuel feedstock. In addition to their potentially high yields per unit land area, algae can grow in unsuitable land for agriculture, includ­ing industrial areas. Thus, their exploitation offers the possibility of a feedstock for producing biofuel that avoids damage to ecosystems and competition with agricul­ture associated with other biomass resources. Although many testing and start-up companies are in operation in several countries, cost information is scarce. Along the aforementioned literature review, a consensus was found that biofuels from algae are, in any case, still at the research and development stage and face numer­ous obstacles related to energy and water needs, and productivity.

Consequently, we revisited the recent developments in biofuel algae-based mar­kets and their technical issues, political standpoints, and environmental impacts. From a research and technology perspective, we stressed the importance of the US bioenergy policies and the European SET plan, as well as by the scenarios from IAE in 2010. These policies inform that several countries have introduced mandates and targets for biofuel expansion and, moreover, that production, international trade, and investment have increased sharply in the last few years.

The introduction of these new policies is essential for lowering the costs of algae biofuels, encourage investment, and develop greater diffusion of this emer­gent technology. Otherwise, in the lack of public policy, currently production costs will eventually remain too high to replace fossil fuels. In the same manner, it is expected that these policies will stimulate innovation to tackle some of the prob­lems in this emerging market.

The problems concerning large-scale production of biodiesel from algal farms on non­arable land include inconsistent and insufficient algal productivities, uncertain capital and operating costs, volatile market prices, and unknown levels of government support. Our survey permits to conclude that although intensive work is being done on many technolog­ical issues, economic studies and respective data are scattered, incomplete, and divergent.

With the onset of new policies, incentives, and massive investment in the pri­vate and public spheres, more researchers are forging new understanding in the science required to make algal biofuels economically feasible. In the present situ­ation, however, the technology to efficiently produce biodiesel from microalgae is not yet competitive. However, with policy support and incentives, we believe that the algal biofuel industry will continue to develop and assuming that this technology follows renewable energy cost trends, costs will decrease to even­tual economic viability. In parallel, processes must be developed to reduce costs and increase production. In this respect, the currently fast rate of development of algae biofuel technology and the actual rising of petroleum-based fuels prices are encouraging algae-based biofuels feasibility in the next few years.

Nevertheless, as shown in this chapter, we are witnessing a rise of companies’ strategies of entering new markets. Reports and news of new activities of algae — based companies are frequently on the news nowadays. These are signs that the uncertainties around the commercialization of this still not mature technology are not sufficient to hinder investment decisions.

Acknowledgments Lauro Andre Ribeiro and Patricia Pereira da Silva would like to acknowledge that this work has been partially supported by FCT under project grant PEst-C/EEI/ UI0308/2011 and from the Brazilian National Council for the Improvement of Higher Education (CAPES). This paper has been framed under the Energy for Sustainability Initiative of the University of Coimbra and supported by the R&D Project EMSURE Energy and Mobility for Sustainable Regions (CENTRO 07 0224 FEDER 002004).