**4. Techno-economic assessment**

Techno-economic assessment is a term which has been used since 2010 [35]. In this assessment, technical performance or potential and the economic feasibility of an innovative technology are evaluated [36]. This assessment can help making right choices during process development and the success rate of market introduction can be raised. It is important to perform a techno-economic assessment in an early development stage of an innovative technology. Therefore, the specific components which will be taken into account, should be considered carefully [35, 37]. Economic potential based on technical information and assumptions can be evaluated via techno-economic analysis. To design a commercial-scale industry or to make a decision for investment, the equipment information must be collected, and profits must be calculated [38]. For various industrial and biosystems evaluation, such as production of biofuel, and fine chemicals from biomass, techno-economic assessment is a useful method [39]. Engineering design, technical information, and costs and profits can be gathered with techno-economic assessment. It can provide support not only for a long-term business decision, but also for on-going process and improvement. In this assessment, system boundaries, flowcharts and assumptions are required, and main technical and economic parameters must be identified, respectively. By using these data, mass and energy balance are determined. According to the model, capital and operating costs are calculated, and profits are calculated to the economic potential [40, 41].

#### **4.1. Techno-economic assessment of microalgae-based productions**

Microalgae are microorganisms which have not very complex cell structures, can be single-celled or multicellular and can grow in aqueous media. It is estimated that more than 50,000 species of microalgae are presented in reports and studies. There are many studies on cultivation of algae. However, each algal species is worth studying separately, because algae species have different mechanism for adapting the cultivation medium and cultivation system. According to their structural properties, growth of each algae can show different growth pattern in these systems and medium. Microalgae species and production conditions should be determined according to the products [42]. Microalgae are produced in open (open ponds) and closed systems (photobioreactors). Considering productivity and obtaining special products such as nutraceuticals and pharmaceuticals, closed systems are more preferable than open systems. However, investment and operating costs of closed systems are higher than those of open systems [43]. Therefore, a very comprehensive economic analysis is required when establishing pilot scale systems. In the production of microalgae, biological factors, non-biological factors and operating parameters are influential. Biological factors include pathogens such as viruses and bacteria, and other algae species; non-biological factors include light, temperature, pH, salinity and nutrients; operating parameters comprises mixing, dilution rate and harvesting frequency [44]. In this section, techno-economic assessments of some microalgae based production systems in the literature have been examined and system costs (investment and operating costs) are shown in **Table 1**. As can be seen in **Table 1**, generally, techno-economic approaches have been carried out for biofuel production. Thomassen et al. [45] developed four different scenarios (basic, intermediate, advanced, alternative) to produce 170 tonnes (dry weight) microalgae per year in Belgium. They used open systems in basic and intermediate scenarios and photobioreactors (PBR) in advanced and alternative scenarios. As a result of the techno-economic assessment, it was seen that the investment costs of photobioreactors were about four times that of open systems and the most profits were in open ponds. It is also stated that this profit can be increased four times by recycling fractions. Juneja and Murthy [46] conducted plant design to produce *Chlorella vulgaris* using 227 million liters of wastewater per day and produce bio-oil from this microalgae. In this design, the bio-oil production process model is divided into five parts (growth, harvesting, hydrothermal liquefaction, bio-oil hydrotreating and co-product recovery). The investment cost of the plant, which will be set up for 28,111 tons of algae per year and 10 million liters of renewable diesel from these algae, is \$ 105 MM; the operating costs would be \$ 17.88 MM. They also stated that the total cost of open pond was \$ 38,645/ha. In the study of Hoffman et al. [47], techno-economic analyzes of microalgae production in algal turf scrubber and open raceway pond systems was performed. As a result of the analysis, the total cost of algal turf scrubber and open raceway pond were \$ 510/tonnes biomass and \$ 673/ tonnes biomass, respectively. It can be seen that capital costs are close for both systems; but operating costs are much higher than for open raceway ponds. Dutta et al. [52] conducted techno-economic analysis of algal biomass cultivation and biofuel production in two different regions (Portugal and USA). Biofuel production was designed as Case A (Portugal) which was carried out by solvent extraction, trans-esterification and product purification processes and as Case B (USA), it was performed by fermentation, distillation, and hydrodeoxygenation processes. Microalgae cultivation and dewatering (centrifuge and filtration) processes

\*

For 10 million gallon of biofuel. \*\*Algae or fuel amount is not given. \*\*\*For 10 million gal/yr biodiesel.

**Table 1.** Investment and operating costs of microalgae based production.

**Species Product System Investment cost Operating cost Ref.** *D. salina* β-carotene Open 66,020 €/tonnes 78,474 €/tonnes [45] *D. salina* β-carotene Open 63,226 €/tonnes 46,686 €/tonnes [45] *D. salina* β-carotene PBR 253,760 €/tonnes 77,977 €/tonnes [45] *H. pluvialis* Astaxanthin PBR 271,449 €/tonnes 80,782 €/tonnes [45] *C. vulgaris* Bio-oil Open 3.73 M \$/tonnes 0.63 M \$/tonnes [46] NA Biofuel Algal turf scrubber 339.64 \$/tonnes 171 \$/tonnes [47] NA Biofuel Open 351.2 \$/tonnes 322.4 \$/tonnes [47] *N. salina* Biofuel\* PBR 327.74 MM \$ \$86.52 MM \$ [48] *C. vulgaris* Biofuel\*\* PBR 5,352,657 \$ 1,977,831 \$ [49] NA Biogas Open 48,157 €/ha 7560 €/ha.yr [50] NA Biodiesel Open 390 MM \$ 37 MM \$/yr [51] NA Biodiesel\*\*\* PBR 990 MM \$ 55 MM \$/yr [51]

Bioeconomic Assessment of Microalgal Production http://dx.doi.org/10.5772/intechopen.73702 201


\*\*\*For 10 million gal/yr biodiesel.

**4. Techno-economic assessment**

200 Microalgal Biotechnology

to the economic potential [40, 41].

**4.1. Techno-economic assessment of microalgae-based productions**

Microalgae are microorganisms which have not very complex cell structures, can be single-celled or multicellular and can grow in aqueous media. It is estimated that more than 50,000 species of microalgae are presented in reports and studies. There are many studies on cultivation of algae. However, each algal species is worth studying separately, because algae species have different mechanism for adapting the cultivation medium and cultivation system. According to their structural properties, growth of each algae can show different growth pattern in these systems and medium. Microalgae species and production conditions should be determined according to the products [42]. Microalgae are produced in open (open ponds) and closed systems (photobioreactors). Considering productivity and obtaining special products such as nutraceuticals and pharmaceuticals, closed systems are more preferable than open systems. However, investment and operating costs of closed systems are higher than those of open systems [43]. Therefore, a very comprehensive economic analysis is required when establishing pilot scale systems. In the production of microalgae, biological factors, non-biological factors and operating parameters are influential. Biological factors include pathogens such as viruses and bacteria, and other algae species; non-biological factors include light, temperature, pH, salinity and nutrients; operating parameters comprises mixing, dilution rate and harvesting frequency [44]. In this section, techno-economic assessments of some microalgae based production systems in the literature have been examined and system costs (investment and operating costs) are shown in **Table 1**. As can be seen in **Table 1**, generally, techno-economic approaches have been carried out for biofuel production. Thomassen et al. [45] developed four different scenarios (basic, intermediate, advanced,

Techno-economic assessment is a term which has been used since 2010 [35]. In this assessment, technical performance or potential and the economic feasibility of an innovative technology are evaluated [36]. This assessment can help making right choices during process development and the success rate of market introduction can be raised. It is important to perform a techno-economic assessment in an early development stage of an innovative technology. Therefore, the specific components which will be taken into account, should be considered carefully [35, 37]. Economic potential based on technical information and assumptions can be evaluated via techno-economic analysis. To design a commercial-scale industry or to make a decision for investment, the equipment information must be collected, and profits must be calculated [38]. For various industrial and biosystems evaluation, such as production of biofuel, and fine chemicals from biomass, techno-economic assessment is a useful method [39]. Engineering design, technical information, and costs and profits can be gathered with techno-economic assessment. It can provide support not only for a long-term business decision, but also for on-going process and improvement. In this assessment, system boundaries, flowcharts and assumptions are required, and main technical and economic parameters must be identified, respectively. By using these data, mass and energy balance are determined. According to the model, capital and operating costs are calculated, and profits are calculated

**Table 1.** Investment and operating costs of microalgae based production.

alternative) to produce 170 tonnes (dry weight) microalgae per year in Belgium. They used open systems in basic and intermediate scenarios and photobioreactors (PBR) in advanced and alternative scenarios. As a result of the techno-economic assessment, it was seen that the investment costs of photobioreactors were about four times that of open systems and the most profits were in open ponds. It is also stated that this profit can be increased four times by recycling fractions. Juneja and Murthy [46] conducted plant design to produce *Chlorella vulgaris* using 227 million liters of wastewater per day and produce bio-oil from this microalgae. In this design, the bio-oil production process model is divided into five parts (growth, harvesting, hydrothermal liquefaction, bio-oil hydrotreating and co-product recovery). The investment cost of the plant, which will be set up for 28,111 tons of algae per year and 10 million liters of renewable diesel from these algae, is \$ 105 MM; the operating costs would be \$ 17.88 MM. They also stated that the total cost of open pond was \$ 38,645/ha. In the study of Hoffman et al. [47], techno-economic analyzes of microalgae production in algal turf scrubber and open raceway pond systems was performed. As a result of the analysis, the total cost of algal turf scrubber and open raceway pond were \$ 510/tonnes biomass and \$ 673/ tonnes biomass, respectively. It can be seen that capital costs are close for both systems; but operating costs are much higher than for open raceway ponds. Dutta et al. [52] conducted techno-economic analysis of algal biomass cultivation and biofuel production in two different regions (Portugal and USA). Biofuel production was designed as Case A (Portugal) which was carried out by solvent extraction, trans-esterification and product purification processes and as Case B (USA), it was performed by fermentation, distillation, and hydrodeoxygenation processes. Microalgae cultivation and dewatering (centrifuge and filtration) processes are common for both cases. As a result of the analysis, the costs in Case A and Case B were calculated as \$ 1279/tonnes and \$ 430/tonnes respectively. The main reason for this difference is that the bioethanol and biogas produced in Case B reduce the energy input to the process. In the case study of Brownbridge et al. [53] techno-economic evaluation of biodiesel production from algae was carried out. The global sensitivity analysis revealed that the algal biodiesel production cost was sensitive to the following parameters: algae oil content > algae annual productivity per unit area > plant production capacity > carbon price increase rate. It is also estimated that for a large-scale plant (100,000 tonnes biodiesel per year), the production cost of biodiesel is 0.8–1.6 €/kg. Batan et al. [48] reviewed the technical and economic feasibility of a closed microalgae cultivation system (photobioreactor) for 10 million gallons of biofuel production per year. As a result of the techno-economic analysis, it is seen that 63% of the total cost is the operating cost, 30% is the investment cost and the remaining 7% is the land purchase. It was also found that the total investment cost was \$ 327.74 MM and the operating cost was \$ 86.52 MM/year. Barlow et al. [54] investigated the feasibility of producing renewable diesel by hydrothermal liquefaction of algal biomass produced in an algal biofilm reactor. Sensitivity analysis shows that the algal productivity is the most important parameter for fuel sales price. In addition, it has been stated that the use of wastewaters in microalgae cultivation has significantly reduced environmental problems. Xin et al. [49], have designed a pilot system for algal-based biofuel production. In the designed pilot scale system, microalgae production was carried out in photobioreactors and the total cost of production was calculated as \$ 0.33/kg biomass. In this system, because of microalgae production in wastewater, the operation cost is reduced. Also chars produced as by-products in the system have been evaluated in the drying stage.

#### **4.2. Case study for algal biorefinery**

In our study, *Chlorella vulgaris* was chosen to produce β-carotene and biodiesel by presenting two scenarios. Production stages were illustrated in **Figure 1**. *Chlorella vulgaris* is highly used in the industrial field because of its high productivity (1.56 g/L.day), high rate of CO<sup>2</sup> fixation (1.99 g/L.day) and high tolerance to environmental conditions [55, 56]. One of the most important of application areas is biodiesel production (due to high lipid content). The lipid content of *Chlorella vulgaris* is approximately 15–25%; carbohydrate and protein contents of *Chlorella vulgaris* are 9 and 55%, respectively [45, 57]. Apart from these, *Chlorella vulgaris* contains high-grade carotenoids. This microalga contains approximately 75 μg/g dry mass of β-carotene [58]. The two scenarios each produce 100 tonnes of dry weight (DW) biomass per year. Each scenario assumes optimal growth conditions as found in the literature. All scenarios produce two products: β-carotene or biodiesel and a fertilizer, consisting of the residual biomass. In addition, glycerol as a by-product will be obtained in the production of biodiesel. The algal-based biorefinery is operated for 270 days per year. The other days cannot be used for cultivation because of inappropriate climate conditions and maintenance requirements.

be 1.56 gr/L day [55]. The maximum specific growth rate was assumed to be 0.28 day−1, based

A centrifuge (C-101) was used to harvest the microalgae (between streams 5 and 6). The centrifuge was assumed to have a biomass recovery rate of 97% and an energy consumption of

flow was increased by drying step (between stream 6 and 7). The technological specifications for the drying step were based on the study of Leach et al. [60]. To calculate the total energy consumption of this spray dryer (S-101), a factor of 2.9 was used to account for the heat exchanger energy transition efficiency. The total energy consumption equaled 5.1 MJ per kg of removed water. Lipid extraction (R-102) was carried out with via using a ratio of 1:1 of hexane in (between streams 7 and 8). The filtration step separated the liquid fraction, which contained the lipids dissolved in the hexane, from the solid fraction, which contained the residual biomass (between streams 11 and 19). No energy consumption was required in this step. The solid fraction went to an evaporation (S-101) step to recycle the hexane. The remaining fraction was sold as fertilizer (stream 19). Hexane mixed with microalgae oil was distilled in a vacuum distillation to obtain a relatively pure stream of oil. The calculation of the energy consumption used the same heat transfer efficiency factor as the drying and evaporation step. In the first case, algae oil was used for biodiesel production where transesterification process (R-103) was carried out with 80% efficiency in

culture medium [59]. A drying step increased the solid concentration of the biomass

(R-101).

Bioeconomic Assessment of Microalgal Production http://dx.doi.org/10.5772/intechopen.73702 203

on the study of Yang et al. 2011. The reactor volume in cultivation stage was 300 m3

**Figure 1.** Illustration of the β-carotene and biodiesel production stages.

1.4 kWh/m3

PBR was selected as cultivation method for the production of the microalgae. *Chlorella* cultures were cultivated in BBM medium. The maximum biomass concentration was assumed to

**Figure 1.** Illustration of the β-carotene and biodiesel production stages.

are common for both cases. As a result of the analysis, the costs in Case A and Case B were calculated as \$ 1279/tonnes and \$ 430/tonnes respectively. The main reason for this difference is that the bioethanol and biogas produced in Case B reduce the energy input to the process. In the case study of Brownbridge et al. [53] techno-economic evaluation of biodiesel production from algae was carried out. The global sensitivity analysis revealed that the algal biodiesel production cost was sensitive to the following parameters: algae oil content > algae annual productivity per unit area > plant production capacity > carbon price increase rate. It is also estimated that for a large-scale plant (100,000 tonnes biodiesel per year), the production cost of biodiesel is 0.8–1.6 €/kg. Batan et al. [48] reviewed the technical and economic feasibility of a closed microalgae cultivation system (photobioreactor) for 10 million gallons of biofuel production per year. As a result of the techno-economic analysis, it is seen that 63% of the total cost is the operating cost, 30% is the investment cost and the remaining 7% is the land purchase. It was also found that the total investment cost was \$ 327.74 MM and the operating cost was \$ 86.52 MM/year. Barlow et al. [54] investigated the feasibility of producing renewable diesel by hydrothermal liquefaction of algal biomass produced in an algal biofilm reactor. Sensitivity analysis shows that the algal productivity is the most important parameter for fuel sales price. In addition, it has been stated that the use of wastewaters in microalgae cultivation has significantly reduced environmental problems. Xin et al. [49], have designed a pilot system for algal-based biofuel production. In the designed pilot scale system, microalgae production was carried out in photobioreactors and the total cost of production was calculated as \$ 0.33/kg biomass. In this system, because of microalgae production in wastewater, the operation cost is reduced. Also chars produced as by-products in the

In our study, *Chlorella vulgaris* was chosen to produce β-carotene and biodiesel by presenting two scenarios. Production stages were illustrated in **Figure 1**. *Chlorella vulgaris* is highly used in the industrial field because of its high productivity (1.56 g/L.day), high rate of CO<sup>2</sup> fixation (1.99 g/L.day) and high tolerance to environmental conditions [55, 56]. One of the most important of application areas is biodiesel production (due to high lipid content). The lipid content of *Chlorella vulgaris* is approximately 15–25%; carbohydrate and protein contents of *Chlorella vulgaris* are 9 and 55%, respectively [45, 57]. Apart from these, *Chlorella vulgaris* contains high-grade carotenoids. This microalga contains approximately 75 μg/g dry mass of β-carotene [58]. The two scenarios each produce 100 tonnes of dry weight (DW) biomass per year. Each scenario assumes optimal growth conditions as found in the literature. All scenarios produce two products: β-carotene or biodiesel and a fertilizer, consisting of the residual biomass. In addition, glycerol as a by-product will be obtained in the production of biodiesel. The algal-based biorefinery is operated for 270 days per year. The other days cannot be used for cultivation because of inappropriate climate conditions and

PBR was selected as cultivation method for the production of the microalgae. *Chlorella* cultures were cultivated in BBM medium. The maximum biomass concentration was assumed to

system have been evaluated in the drying stage.

**4.2. Case study for algal biorefinery**

202 Microalgal Biotechnology

maintenance requirements.

be 1.56 gr/L day [55]. The maximum specific growth rate was assumed to be 0.28 day−1, based on the study of Yang et al. 2011. The reactor volume in cultivation stage was 300 m3 (R-101). A centrifuge (C-101) was used to harvest the microalgae (between streams 5 and 6). The centrifuge was assumed to have a biomass recovery rate of 97% and an energy consumption of 1.4 kWh/m3 culture medium [59]. A drying step increased the solid concentration of the biomass flow was increased by drying step (between stream 6 and 7). The technological specifications for the drying step were based on the study of Leach et al. [60]. To calculate the total energy consumption of this spray dryer (S-101), a factor of 2.9 was used to account for the heat exchanger energy transition efficiency. The total energy consumption equaled 5.1 MJ per kg of removed water. Lipid extraction (R-102) was carried out with via using a ratio of 1:1 of hexane in (between streams 7 and 8). The filtration step separated the liquid fraction, which contained the lipids dissolved in the hexane, from the solid fraction, which contained the residual biomass (between streams 11 and 19). No energy consumption was required in this step. The solid fraction went to an evaporation (S-101) step to recycle the hexane. The remaining fraction was sold as fertilizer (stream 19). Hexane mixed with microalgae oil was distilled in a vacuum distillation to obtain a relatively pure stream of oil. The calculation of the energy consumption used the same heat transfer efficiency factor as the drying and evaporation step. In the first case, algae oil was used for biodiesel production where transesterification process (R-103) was carried out with 80% efficiency in

**Figure 2.** Process flow diagram of biodiesel production from microalgae.

**Figure 2** which was created by Chemcad program (between streams 14 and 25). As for the second case, β-carotene production from microalgae after isolation and purification was assumed to be approximately 45%. Dry microalgae biomass was extracted (R-102) with acetone and β-carotene was obtained after sonication process in **Figure 3** (between stream 14 and 18). Inputs and outputs of β-carotene and biodiesel production from microalgae were given in **Table 2**.

**Figure 3.** Process flow diagram of β-carotene production from microalgae.

Water (tonnes/yr) 81,000 81,000

Product (tonnes/yr) 6.5 12

Waste algae paste (tonnes/yr) 93.5 85

**Table 2.** Inputs and outputs of β-carotene and biodiesel production from microalgae.

(tonnes/yr) – 3\*

 (tonnes/yr) 142,688 142,688 Nutrient (tonnes/yr) 9871 9871 Hexane (liter) – 628.29 Acetone (liter) 4000 – Electricity (GJ/yr) 10,675 9985 Heat (GJ/yr) 2231 2231 Land use (ha) 1.5 1.5

**Inputs**

CO2

**Outputs**

By-product\*

\* Glycerol. **β-carotene Biodiesel**

Bioeconomic Assessment of Microalgal Production http://dx.doi.org/10.5772/intechopen.73702 205

**Table 3** illustrates the main economic results for the two scenarios. When **Table 3** is examined, it is seen that the investment and operating costs are very close to each other in the two scenarios. The investment costs are the highest of all scenarios, due to the costs of the photobioreactor. The photobioreactor installation accounts for about 50% of the investment costs. Nutrients and chemicals account for about 30% of operating costs; and salaries constitute about 20% [49]. When revenues are examined, it is seen that there is a great difference. Because of this situation, β-carotene is a more valuable product than biodiesel. The average selling price of β-carotene is € 1370 per kg and the selling price of biodiesel is € 0.82/kg [45, 61, 62]. **Table 3** shows that this system is more suitable for β-carotene production. In order for biodiesel production to become economical, investment and operating costs must be reduced very seriously. In particular, the use of open ponds instead of photobioreactor will significantly reduce the investment cost. Furthermore, the use of an oil-rich microalga, production in wastewater and the use of recycled fractions will make biodiesel production more economical [45].

As mentioned in the introduction section, unlike the classical economy, bioeconomy includes the concepts of innovation, competition, knowledge based value added, and employment and sustainability. Within this approach, biological based productions or innovations are evaluated not only with techno-economic aspects, but with their systematic evaluation of the environmental effects of inputs and outputs at all stages in their life cycle. Life cycle involves modeling the life cycle of a product or production system. Life cycle analysis shows

**Figure 3.** Process flow diagram of β-carotene production from microalgae.

**Figure 2** which was created by Chemcad program (between streams 14 and 25). As for the second case, β-carotene production from microalgae after isolation and purification was assumed to be approximately 45%. Dry microalgae biomass was extracted (R-102) with acetone and β-carotene was obtained after sonication process in **Figure 3** (between stream 14 and 18). Inputs and outputs

**Table 3** illustrates the main economic results for the two scenarios. When **Table 3** is examined, it is seen that the investment and operating costs are very close to each other in the two scenarios. The investment costs are the highest of all scenarios, due to the costs of the photobioreactor. The photobioreactor installation accounts for about 50% of the investment costs. Nutrients and chemicals account for about 30% of operating costs; and salaries constitute about 20% [49]. When revenues are examined, it is seen that there is a great difference. Because of this situation, β-carotene is a more valuable product than biodiesel. The average selling price of β-carotene is € 1370 per kg and the selling price of biodiesel is € 0.82/kg [45, 61, 62]. **Table 3** shows that this system is more suitable for β-carotene production. In order for biodiesel production to become economical, investment and operating costs must be reduced very seriously. In particular, the use of open ponds instead of photobioreactor will significantly reduce the investment cost. Furthermore, the use of an oil-rich microalga, production in wastewater and the use of recycled fractions will make biodiesel production more eco-

As mentioned in the introduction section, unlike the classical economy, bioeconomy includes the concepts of innovation, competition, knowledge based value added, and employment and sustainability. Within this approach, biological based productions or innovations are evaluated not only with techno-economic aspects, but with their systematic evaluation of the environmental effects of inputs and outputs at all stages in their life cycle. Life cycle involves modeling the life cycle of a product or production system. Life cycle analysis shows

of β-carotene and biodiesel production from microalgae were given in **Table 2**.

**Figure 2.** Process flow diagram of biodiesel production from microalgae.

nomical [45].

204 Microalgal Biotechnology


**Table 2.** Inputs and outputs of β-carotene and biodiesel production from microalgae.


*e*CO2 = (Cf

which was lower than emissions of CO2

emissions of methane and N2

covered nitrogen leading to N2

which produces N2

that of CO2

izers maybe has the potential to produce N2

dominantly by impacts, such as the demand for CO2

diesel process. Sander and Murthy [68], reported that; net CO2

centrifuge processes are −6670 and −3778 MJ/functional unit, CO<sup>2</sup>

/Ef)(MWCO2 /MWC) (1)

Bioeconomic Assessment of Microalgal Production http://dx.doi.org/10.5772/intechopen.73702

from the combustion of the same amount of coal

O respectively totaled 14 and 23% of the whole pathway

O. Nitrogen transported to fields to displace mineral fertil-

O, a potent greenhouse gas with global warming potential 298 times

. Agricultural techniques may be reduce capital costs substantially; however,

O emissions. Nitrogen fraction, especially that

and fertilizer. To reduce these impacts,

emissions are −20.9 and

207

emissions are positive for

O. Lipid

In the case study of this chapter, carbon dioxide emission was found as 0.033 tCO2/kWh

(anthracite) and natural gas. This indicates the advantage and positive contribution of the algal productions over fossil fuel sources. There is no global warming impact of the bio-

135.7 kg/functional unit for a process utilizing a filter press and centrifuge in harvesting of algae. Furthermore, the −13.96 kg of total air emissions per functional unit, 18.6 kg of waterborne wastes, and 0.28 kg of solid waste are calculated as output. The largest energy input (89%) is in the natural gas drying of the algae. While net energy for filter press and

the centrifuge process but they are negative for the filter press process. Moreover, 20.4 m<sup>3</sup> of wastewater is lost from the growth ponds during evaporation in the 4-day growth cycle. LCA has one major obstacle in algae technology: the need to efficiently process the algae into its usable components. LCA clearly shows a need for new technologies to make algae biofuels a sustainable, commercial reality. Another study reported that; when algal biofuel production modeled, substantial reductions in GHG emissions were achieved in the model due to the non-fossil treatment of the carbon in the biofuel and because substantial energy and nutrient recovery credits from processing of residuals were included. Fugitive

GHG emissions. Techno economic modeling must choose technologies that control these emissions. LCA requires superior data on fugitive emissions and must account for unre-

fraction and productivity are two strong drivers of economic viability. The large global warming potential for methane could make the costs for controlling methane emissions higher than the economic value returned and in that case, sustainability and economic drivers would be at odds [69]. Clarens et al. [66], reported that, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results of this study indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. The algae cultivation is driven

flue gas, wastewater and novel biofuel production methods such as supercritical process, ultrasound and microwave assisted processes could be used to stabilize most of the environmental loads associated with algae [70]. To represent the benefits of algae production coupled with wastewater treatment, was expanded to include three different municipal wastewater as sources of nitrogen and phosphorus. The use of source-separated urine was

found to make algae more environmentally beneficial than the terrestrial crops.

these techniques need attentive evaluation with regard to fugitive emissions of N<sup>2</sup>

**Table 3.** The economic results for the two scenarios.

all environmental impacts of an action; a system which comprises of evaluation of raw materials from the nature, and all the wastes that are returned to the nature. This assessment includes all the effects on the air, water and soil during the production, use and eventual destruction of the raw materials, including energy, as far as the product which is processed. This analysis is used both to identify and measure the effects directly (emissions produced during production and energy used etc.) as well as indirect (raw material disposal, product disposal, consumer use and disposal, etc.). These effects are directly connected with sustainability which is the ability to continuously process without consuming the basic resources of a society, an ecosystem or other similar interactive systems and without adversely affecting the environment. In this context, potential impact indicators are necessary for the selection and development of energy systems for the future. These indicators provide a common basis for comparing and evaluating different energy systems [63]. Bioethanol and biodiesel obtained from agricultural sources have lower global warming potentials, on the other hand, there are other environmental problems such as eutrophication, resource depletion and ecotoxicity that occur. Algal biotechnological production is a promising biotechnological area because of high photosynthesis efficiency, and low area requirement for cultivation of algae, and also nitrate and phosphate ions in wastewater can be a food source for algae. In addition to that, algae can utilize industrial CO2 emissions directly as a carbon source [64]. In the recent life cycle analysis studies on algae systems show that sustainable productions seem to have increased. In these studies, it has been found that CO2 emissions are effectively reduced in comparison of other production facilities [65]. Algae can recycle of pollutant nitrogen in wastewater. The use of a toxic substance such as urea by algae also shows the contribution of algae to the environment [66]. When all stages of the algal process are taken into consideration, it is seen that requirement of electricity occurs mostly during the cultivation of the algae. The energy requirements of all stages and global warming potentials are much lower than the growth phase. The energy requirement in the algal system and global warming potential depend on the oil productivity during growing, the circulation rate of algae during growing, and the industrial CO2 gas concentration [67]. 40% of CO2 emissions are generated from electricity generation, and 30% are from vehicle fuels. In 2013, global CO2 emissions are 36 gigatonnes. Natural processes absorb half of this amount. Therefore, carbon dioxide shows a net increase of 18 gigatonnes per year in the atmosphere. One tonne of carbon is equivalent to MWCO2/MWC = 44/12 = 3.7 tonnes of carbon dioxide. In the equation, MWCO2 is the molecular weight of carbon dioxide, MWC is the molecular weight of carbon, eCO2 is the carbon dioxide emission (kgCO2/kWh), Cf is the carbon content in the fuel (kgC/kgfuel), and Ef is the energy content of the fuel (kWh/kgfuel). Carbon dioxide emissions can be calculated from the following formula:

Bioeconomic Assessment of Microalgal Production http://dx.doi.org/10.5772/intechopen.73702 207

$$e\_{\rm coz} = \left(\mathbf{C}\_{\rm r}/\mathbf{E}\_{\rm i}\right) \text{[MW}\_{\rm coz}/\mathbf{MW}\_{\rm c}\text{]}\tag{1}$$

In the case study of this chapter, carbon dioxide emission was found as 0.033 tCO2/kWh which was lower than emissions of CO2 from the combustion of the same amount of coal (anthracite) and natural gas. This indicates the advantage and positive contribution of the algal productions over fossil fuel sources. There is no global warming impact of the biodiesel process. Sander and Murthy [68], reported that; net CO2 emissions are −20.9 and 135.7 kg/functional unit for a process utilizing a filter press and centrifuge in harvesting of algae. Furthermore, the −13.96 kg of total air emissions per functional unit, 18.6 kg of waterborne wastes, and 0.28 kg of solid waste are calculated as output. The largest energy input (89%) is in the natural gas drying of the algae. While net energy for filter press and centrifuge processes are −6670 and −3778 MJ/functional unit, CO<sup>2</sup> emissions are positive for the centrifuge process but they are negative for the filter press process. Moreover, 20.4 m<sup>3</sup> of wastewater is lost from the growth ponds during evaporation in the 4-day growth cycle. LCA has one major obstacle in algae technology: the need to efficiently process the algae into its usable components. LCA clearly shows a need for new technologies to make algae biofuels a sustainable, commercial reality. Another study reported that; when algal biofuel production modeled, substantial reductions in GHG emissions were achieved in the model due to the non-fossil treatment of the carbon in the biofuel and because substantial energy and nutrient recovery credits from processing of residuals were included. Fugitive emissions of methane and N2 O respectively totaled 14 and 23% of the whole pathway GHG emissions. Techno economic modeling must choose technologies that control these emissions. LCA requires superior data on fugitive emissions and must account for unrecovered nitrogen leading to N2 O. Nitrogen transported to fields to displace mineral fertilizers maybe has the potential to produce N2 O emissions. Nitrogen fraction, especially that which produces N2 O, a potent greenhouse gas with global warming potential 298 times that of CO2 . Agricultural techniques may be reduce capital costs substantially; however, these techniques need attentive evaluation with regard to fugitive emissions of N<sup>2</sup> O. Lipid fraction and productivity are two strong drivers of economic viability. The large global warming potential for methane could make the costs for controlling methane emissions higher than the economic value returned and in that case, sustainability and economic drivers would be at odds [69]. Clarens et al. [66], reported that, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results of this study indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. The algae cultivation is driven dominantly by impacts, such as the demand for CO2 and fertilizer. To reduce these impacts, flue gas, wastewater and novel biofuel production methods such as supercritical process, ultrasound and microwave assisted processes could be used to stabilize most of the environmental loads associated with algae [70]. To represent the benefits of algae production coupled with wastewater treatment, was expanded to include three different municipal wastewater as sources of nitrogen and phosphorus. The use of source-separated urine was found to make algae more environmentally beneficial than the terrestrial crops.

all environmental impacts of an action; a system which comprises of evaluation of raw materials from the nature, and all the wastes that are returned to the nature. This assessment includes all the effects on the air, water and soil during the production, use and eventual destruction of the raw materials, including energy, as far as the product which is processed. This analysis is used both to identify and measure the effects directly (emissions produced during production and energy used etc.) as well as indirect (raw material disposal, product disposal, consumer use and disposal, etc.). These effects are directly connected with sustainability which is the ability to continuously process without consuming the basic resources of a society, an ecosystem or other similar interactive systems and without adversely affecting the environment. In this context, potential impact indicators are necessary for the selection and development of energy systems for the future. These indicators provide a common basis for comparing and evaluating different energy systems [63]. Bioethanol and biodiesel obtained from agricultural sources have lower global warming potentials, on the other hand, there are other environmental problems such as eutrophication, resource depletion and ecotoxicity that occur. Algal biotechnological production is a promising biotechnological area because of high photosynthesis efficiency, and low area requirement for cultivation of algae, and also nitrate and phosphate ions in wastewater can be a food source for algae. In addi-

Investment cost (€) 1,736,614 1,766,909 Operational costs (€/yr) 504,710 501,277 Revenues (€/yr) 4,270,500 11,698

recent life cycle analysis studies on algae systems show that sustainable productions seem to

in comparison of other production facilities [65]. Algae can recycle of pollutant nitrogen in wastewater. The use of a toxic substance such as urea by algae also shows the contribution of algae to the environment [66]. When all stages of the algal process are taken into consideration, it is seen that requirement of electricity occurs mostly during the cultivation of the algae. The energy requirements of all stages and global warming potentials are much lower than the growth phase. The energy requirement in the algal system and global warming potential depend on the oil productivity during growing, the circulation rate of algae during

gas concentration [67]. 40% of CO2

are 36 gigatonnes. Natural processes absorb half of this amount. Therefore, carbon dioxide shows a net increase of 18 gigatonnes per year in the atmosphere. One tonne of carbon is equivalent to MWCO2/MWC = 44/12 = 3.7 tonnes of carbon dioxide. In the equation, MWCO2 is the molecular weight of carbon dioxide, MWC is the molecular weight of carbon, eCO2 is the

the energy content of the fuel (kWh/kgfuel). Carbon dioxide emissions can be calculated from

from electricity generation, and 30% are from vehicle fuels. In 2013, global CO2

emissions directly as a carbon source [64]. In the

**β-carotene Biodiesel**

is the carbon content in the fuel (kgC/kgfuel), and Ef

emissions are effectively reduced

emissions are generated

emissions

is

tion to that, algae can utilize industrial CO2

**Table 3.** The economic results for the two scenarios.

206 Microalgal Biotechnology

growing, and the industrial CO2

the following formula:

carbon dioxide emission (kgCO2/kWh), Cf

have increased. In these studies, it has been found that CO2
