Biomass Production Costs Research Articles

Biomass Feedstocks for Liquid Biofuels Production in Hawaii & Tropical Islands: A Review

Many tropical islands, including Aruba, Seychelles, Mauritius, and Pacific Island countries, are entirely dependent on importing fossil fuels to meet their energy demands. Due to global warming, improving energy use efficiency and developing regionally available renewable energy resources are necessary to reduce carbon emissions. This review analyzed and identified biomass feedstocks to produce liquid biofuels targeting tropical islands, particularly focusing on Hawaii as a case study. Transportation and energy generation sectors consume 25.5% and 11.6%, respectively, of Hawaii's imported fossil fuels. Various nonedible feedstocks with information on their availability, production, and average yields of oils, fiber, sugars, and lipid content for liquid biofuels production are identified to add value to the total energy mix. The available biomass conversion technologies and production costs are summarized. In addition, a section on potentially using sewage sludge to produce biodiesel is also included. Based on a comparative analysis of kamani, croton, pongamia, jatropha, energycane, Leucaena hybrid, gliricidia, and eucalyptus feedstock resources, this study proposes that Hawaii and other similar tropical regions can potentially benefit from growing and producing economical liquid biofuels locally, especially for the transportation and electricity generation sectors

Techno-economic assessment for the production of algal fuels and value-added products: opportunities for high-protein microalgae conversion

BackgroundMicroalgae possess numerous advantages for use as a feedstock in producing renewable fuels and products, with techno-economic analysis (TEA) frequently used to highlight the economic potential and technical challenges of utilizing this biomass in a biorefinery context. However, many historical TEA studies have focused on the conversion of biomass with elevated levels of carbohydrates and lipids and lower levels of protein, incurring substantial burdens on the ability to achieve high cultivation productivity rates relative to nutrient-replete, high-protein biomass. Given a strong dependence of algal biomass production costs on cultivation productivity, further TEA assessment is needed to understand the economic potential for utilizing potentially lower-cost but lower-quality, high-protein microalgae for biorefinery conversion.ResultsIn this work, we conduct rigorous TEA modeling to assess the economic viability of two conceptual technology pathways for processing proteinaceous algae into a suite of fuels and products. One approach, termed mild oxidative treatment and upgrading (MOTU), makes use of a series of thermo-catalytic operations to upgrade solubilized proteins and carbohydrates to hydrocarbon fuels, while another alternative focuses on the biological conversion of those substrates to oxygenated fuels in the form of mixed alcohols (MA). Both pathways rely on the production of polyurethanes from unsaturated fatty acids and valorization of unconverted solids for use as a material for synthesizing bioplastics. The assessment found similar, albeit slightly higher fuel yields and lower costs for the MA pathway, translating to a residual solids selling price of $899/ton for MA versus $1033/ton for MOTU as would be required to support a $2.50/gallon gasoline equivalent (GGE) fuel selling price. A variation of the MA pathway including subsequent upgrading of the mixed alcohols to hydrocarbon fuels (MAU) reflected a required solids selling price of $975/ton.ConclusionThe slight advantages observed for the MA pathway are partially attributed to a boundary that stops at oxygenated fuels versus fungible drop-in hydrocarbon fuels through a more complex MOTU configuration, with more comparable results obtained for the MAU scenario. In either case, it was shown that an integrated algal biorefinery can be economical through optimal strategies to utilize and valorize all fractions of the biomass.

Harvesting Technologies and Costs of Biomass Production from Energy Crops Cultivated on Farms in the Małopolska Region

This study aimed to assess biomass production costs from perennial energy crops, such as Miscanthus giganteus, Sida hermaphrodita, and coppiced willow, in selected agricultural holdings. This assessment was based on applied technologies for harvesting the biomass of the energy crops mentioned above. The scope of the study included research on ten farms located in Małopolska and establishing the possibility of biomass production from selected energy crops in these entities. Biomass production costs have been estimated using the computer application “Bioalkylation”. The result of the research was the answer to the question: what can be the cost range of biomass production from perennial energy crops for the crops Miscanthus giganteus, Sida hermaphrodita, and coppiced willow as the most popular plants? The study shows that production costs depend primarily on the harvesting technology used and the machinery used in the farm. The harvest with rotary mowers, small presses, and windrows was applied regarding Miscanthus giganteus and Sida hermaphrodita. The costs of biomass production were, on average, 424.7 EUR ha−1 for Miscanthus giganteus and 278.9 EUR ha−1 for Sida hermaphrodita. Concerning tonne, this was 37.6 EUR t−1 for Miscanthus giganteus and 30.0 EUR t−1 for Sida hermaphrodita, respectively. In the case of harvesting energy willow, in the form of whole shoots, inefficient and labour-intensive technologies using chainsaws and combustion cutters were applied. The biomass production costs were thus the highest among the assessed plants and amounted, on average, to 612.1 EUR ha−1, which in terms of tonne corresponded to a value of 30.6 EUR. The obtained results and the analysis presented in the paper may help in planning the cultivation of perennial energy crops in order to obtain biomass used for heating purposes on a farm.

Evaluating the minimum fuel selling price of algae-derived biofuel from hydrothermal liquefaction

Hydrothermal liquefaction (HTL) of algae is a viable pathway to produce drop-in fuels. However, determining the optimal processing conditions of the algae-derived biofuel via HTL is challenging due to the tradeoff between biomass productivity, lipid content, and biocrude energy yield. To address this issue, we integrate a biomass productivity model that correlates the lipid content and biomass productivity, a biomass production cost conclumodel that correlates the biomass productivity and minimum selling price of biomass, and a machine learning model that predicts biocrude energy yield based on biochemical compositions and processing conditions. Results are fed into a techno-economic model to determine the minimum fuel selling price (MFSP) of algae-derived biofuel. Our results demonstrate the integration of the models gives quick evaluations of the MFSP of algae-derived biofuel and provides insights on optimal pathways to achieve better economic performance. In particular, algae with lipid content around 20–25% at 300 °C give the most favorable economic performance ($6/gasoline-gallon-equivalent (GGE)).

Evaluation of Microalgae Culture in PA and Commercial Urea Media

This work aimed to evaluate the growth and cost cultivation of Chlorella sp microalgae in PA and commercial urea medium solutions compared to BBM standard medium. We cultivated the microalgae Chlorella sp in BBM, PA urea, and commercial urea media, evaluating their growth for 8 days. In addition, we appraised the cost of the culture media considering the quotation of the reagents and the mass used for pilot-scale cultivation (100l). It was possible to observe the similar growth of microalgae with urea PA and BBM. The use of urea PA as a culture media for microalgae has the potential to reduce the cost of the medium by 68%. Thus, the cultivation of Chlorella in urea medium represents an alternative to reduce the production costs of biomass from this microorganism.

Feasibility of Utilizing Wastewaters for Large-Scale Microalgal Cultivation and Biofuel Productions Using Hydrothermal Liquefaction Technique: A Comprehensive Review.

The two major bottlenecks faced during microalgal biofuel production are, (a) higher medium cost for algal cultivation, and (b) cost-intensive and time consuming oil extraction techniques. In an effort to address these issues in the large scale set-ups, this comprehensive review article has been systematically designed and drafted to critically analyze the recent scientific reports that demonstrate the feasibility of microalgae cultivation using wastewaters in outdoor raceway ponds in the first part of the manuscript. The second part describes the possibility of bio-crude oil production directly from wet algal biomass, bypassing the energy intensive and time consuming processes like dewatering, drying and solvents utilization for biodiesel production. It is already known that microalgal drying can alone account for ∼30% of the total production costs of algal biomass to biodiesel. Therefore, this article focuses on bio-crude oil production using the hydrothermal liquefaction (HTL) process that converts the wet microalgal biomass directly to bio-crude in a rapid time period. The main product of the process, i.e., bio-crude oil comprises of C16-C20 hydrocarbons with a reported yield of 50–65 (wt%). Besides elucidating the unique advantages of the HTL technique for the large scale biomass processing, this review article also highlights the major challenges of HTL process such as update, and purification of HTL derived bio-crude oil with special emphasis on deoxygenation, and denitrogenation problems. This state of art review article is a pragmatic analysis of several published reports related to algal crude-oil production using HTL technique and a guide towards a new approach through collaboration of industrial wastewater bioremediation with rapid one-step bio-crude oil production from chlorophycean microalgae.

Techno-economic analysis of livestock urine and manure as a microalgal growth medium

Microalgae have the potential to utilize the nutrients in livestock urine and manure (LUM) for the production of useful biomass, which can be used as a source of bioindustry. This study aims to evaluate the economic benefits of LUM feedstock that have not been clearly discussed before. Two types of photobioreactors were designed with a capacity of 200 m3 d-1. Using the experimental data, the economic feasibility of the suggested processes was evaluated via techno-economic analysis. Itemized cost estimation indicated that the submerged membrane photobioreactor has a lower unit production cost (5.4 $ to 5.1 $ kg−1) than the conventional photobioreactor system (14.6 $ to 13.8 $ kg−1). In addition, LUM-based growth is another good option for reducing the unit production cost of biomass. The revenues from lowering the cost of LUM treatment significantly contribute to enhancing the economic profitability, where the break-even prices were 1.18 $ m−3 (photobioreactor) and 0.98 $ m−3 (submerged membrane photobioreactor). Finally, this study provides several emerging suggestions to reduce microalgal biomass production costs.

Sunlight Intensity, Photosynthetically Active Radiation Modelling and Its Application in Algae-Based Wastewater Treatment and Its Cost Estimation

In algal pond used for treating wastewater, a part of the solar radiation (PAR) is used by algae for photosynthesis, and rest of the solar energy is wasted. To date, no studies have been conducted that optimize these aspects (wasted solar radiation for heat production) from an operational cost perspective. Therefore, a model is developed for the estimation of photosynthetically active radiation (PAR) from solar radiation. Subsequently, derived PAR was utilized in the optimization algorithm. Experimental data on PAR and solar radiation were used to obtain empirical parameters of the developed model. Using empirical parameters, diurnal PAR was estimated for other locations for which the diurnal variation of solar radiation was not available. Afterwards, the estimated solar radiation was used to obtain the cost of algal biomass production using wastewater. For this purpose, a cost function was minimized. The cost function contains various cost components of algae-based wastewater treatment. The major costs of the treatment were incurred by the sunlight harvesting, and distribution equipment, whereas the major income was registered through the conversion of sunlight to heat and biomass production. The yearly cost of treating 1m3 wastewater in the proposed wastewater treatment plant could be varied from 186 to −44 (Rs, INR). The capital cost of constructing a proposed treatment plant having a capacity of 1000 m3/day varied from 11–45 crores INR.

Pigment production by Scenedesmus dimorphus using different low‐cost and alternative culture media

AbstractBACKGROUNDThis study investigated the feasibility of producing pigments from Scenedesmus dimorphus using different low‐cost synthetic and alternative media. Thus the influence of nitrogen and phosphorus deficiency, different nitrogen sources and alternative culture media (wheat bran, garlic powder, wheat bran supplemented with garlic powder) on pigment and biomass production was evaluated.RESULTSAmong the three sources of nitrogen studied (ammonium sulfate, urea and sodium nitrate), urea was the cheapest efficient alternative source of nitrogen for pigment production, especially total chlorophylls (67.38 μg L−1 d−1), by this strain, without strongly affecting biomass yield. Phosphorus deficiency had no negative effect on biomass production, but improved the production of zeaxanthin and chlorophyll b by13.1% and 26.8%, respectively, compared to control. Compared to BG‐11 medium, the alternative garlic powder medium increased the biomass yield of S. dimorphus by 5.2 times, improved the productivity of xanthophylls and contributed to the accumulation of β‐carotene.Wheat bran medium was found to be efficient as a zero‐cost culture medium for the production of pigments, where S. dimorphus accumulated twice the total pigment concentration of the control, with high β‐carotene productivity (38.58 ± 11.94 μg L−1 d−1). The addition of garlic powder to wheat bran increased the biomass (3.14 g L−1) and pigment productivity (216.86 ± 2.06 μg L−1 d−1) by 28.5 and 1.4 times, respectively, but inhibited zeaxanthin biosynthesis. This alternative medium reduced biomass and pigment production costs by 99.80% and 96.21%, respectively.CONCLUSIONWheat bran supplemented with garlic powder showed good application potential for the industrial production of biomass and pigments from S. dimorphus in open cultivation systems where garlic powder might be used simultaneously for biomass and pigment accumulation, and for biological contamination control. © 2021 Society of Chemical Industry (SCI).

Multi-product biorefinery from Arthrospira platensis biomass as feedstock for bioethanol and lactic acid production

With the aim to reach the maximum recovery of bulk and specialty bioproducts while minimizing waste generation, a multi-product biorefinery for ethanol and lactic acid production from the biomass of cyanobacterium Arthrospira platensis was investigated. Therefore, the residual biomass resulting from different pretreatments consisting of supercritical fluid extraction (SF) and microwave assisted extraction with non-polar (MN) and polar solvents (MP), previously applied on A. platensis to extract bioactive metabolites, was further valorized. In particular, it was used as a substrate for fermentation with Saccharomyces cerevisiae LPB-287 and Lactobacillus acidophilus ATCC 43121 to produce bioethanol (BE) and lactic acid (LA), respectively. The maximum concentrations achieved were 3.02 ± 0.07 g/L of BE by the MN process at 120 rpm 30 °C, and 9.67 ± 0.05 g/L of LA by the SF process at 120 rpm 37 °C. An economic analysis of BE and LA production was carried out to elucidate the impact of fermentation scale, fermenter costs, production titer, fermentation time and cyanobacterial biomass production cost. The results indicated that the critical variables are fermenter scale, equipment cost, and product titer; time process was analyzed but was not critical. As scale increased, costs tended to stabilize, but also more product was generated, which causes production costs per unit of product to sharply decrease. The median value of production cost was US$ 1.27 and US$ 0.39, for BE and LA, respectively, supporting the concept of cyanobacterium biomass being used for fermentation and subsequent extraction to obtain ethanol and lactic acid as end products from A. platensis.

Ultrahigh-cell-density heterotrophic cultivation of the unicellular green alga Chlorella sorokiniana for biomass production.

Heterotrophic cultivation of Chlorella has achieved commercial success, but the application of Chlorella biomass is still limited due to the high cost of biomass production. In this study, an effective and industrially scalable heterotrphic cultivation technology has been developed for a production strain Chlorella sorokiniana GT-1. Under the optimized culturing conditions, the ultrahigh biomass concentration of 271 and 247 g L-1 was achieved in 7.5 L bench-scale and 1000 L pilot-scale fermenters, respectively. Technoeconomic (TE) analysis indicated that the production cost of C. sorokiniana GT-1 could be reduced to $1601.27 per ton of biomass if the biomass concentration reached 200 g L-1 , which is 24.2% lower than that of the reported highest Chlorella biomass production through fermentation with the same TE model. Under the same growth conditions, the maximum biomass concentration of a low-starch mutant SLM2 was reduced to 93 g L-1 , which was 54% lower than that of the wild type, indicating the capabilities of C. sorokiniana GT-1 cells in accumulating large amounts of starch are essential for achieving the ultrahigh-cell-density under the heterotrophic conditions. In addition, the ultrahigh-cell-density growth potential of C. sorokiniana GT-1 cells was inferred to be related to the intrinsic biological characteristics including the tolerance to low dissolved oxygen and a moderate doubling time under the heterotrophic conditions as well. The breakthrough in cultivation technology is promising for Chlorella industry and would expand its applications in food and feed.

Development of microalgal biofilm for wastewater remediation: from mechanism to practical application

AbstractThe high cost of biomass harvesting by centrifugation and high safety risks of collected algal biomass by chemical flocculation are serious problems jeopardizing the industrial implementation of microalgae bio‐products. Recently, microalgae immobilization is regarded as a promising technology with the potential of lowering biomass production cost and ensuring biomass safety in the industry. Therefore, microalgal biofilms, an effective and affordable way to immobilize algal cells, are emerging into the limelight. This paper summarizes the progress achieved in biofilm system design and biofilm formation mechanisms. Newly designed algal biofilm systems are compared to demonstrate their advantages and weaknesses. Besides, mechanisms associated with the two steps –initial attachment of microalgae and biofilm thickening – of biofilm formation are discussed in this paper. Factors such as substratum material, algal strain and operational parameters, which could impact the formation and operation of algal biofilm, are demonstrated. Efforts devoted to the industrial application of algal biofilm to treat wastewater are discussed. The biotechnology of microalgal biofilm is currently at the critical stage of developing from fundamental research to industrial implementation. Undeniably, there are still many problems that limit the wide use of algal biofilm for biomass production and wastewater treatment. In this paper, we present some potential solutions to current problems and discuss the development trends of algal biofilm in the foreseeable future. It is expected that by addressing current problems microalgal biofilm will be widely used at the industrial scale. © 2021 Society of Chemical Industry (SCI).

Assessing the Cost of Biomass and Bioenergy Production in Agroindustrial Processes

This paper presents bioenergy value chain modelling to estimate the biomass and bioenergy cost of production and biomass netback in combined heat and power (CHP) systems. Modelling compares biomass cost and netback to analyse the feasibility of CHP systems, as well as the internal rate of return (IRR) and payback period (PBP). Models are implemented into the IMP Bio2Energy® software (Instituto Mexicano del Petróleo, Mexico City, Mexico) for practical application and demonstrated for bioenergy generation in the agroindustrial processes of tequila production, coffee and orange processing using as biomass the agave bagasse, coffee pulp and orange peels coproducts, respectively. Results show that the CHP systems are economically feasible, i.e., biomass cost of production is lower than netback, PBP between 3 and 4 years and IRR > 20%. The cost of bioenergy is lower than the cost of fuel oil and grid electricity being replaced. The sensitivity analysis for boiler steam pressure showed that there is an optimal pressure for coffee pulp (40 bar), a threshold pressure for orange (60 bar) and agave bagasse (70 bar). Sensitivity to biomass input indicated a maximum capacity where economy of scale does not produce any improvement in the indicators. Results demonstrate the usefulness of the modelling approach and IMP Bio2Energy® in analysing biomass CHP systems.

Waste Is the New Wealth – Recovering Resources From Poultry Wastewater for Multifunctional Microalgae Feedstock

To meet the increasing demands of the growing population and to cope with the challenges of global change, both the production of biological feedstock and the recovery of recyclable natural resources play a critical role. Microalgal biomass is a promising source of renewable multifunctional feedstock, but the production is costly and requires large amounts of water. Here, we explored the potential of using wastewater as culture medium to lower the economic and environmental costs of microalgae biomass production and evaluated its valorization opportunities for animal feed production. As a proof of principle, we show that Chlorella sorokiniana can be cultivated on poultry wastewater, with a 83 and 113% increase in productivity when wastewater was first 50% diluted with tap water or standard growth medium, respectively. Wastewater sterilization before use enhanced algal growth with 36–118%, but only when wastewater was 25–50% diluted with standard medium. In contrast, it offered no additional benefits when dilutions were made with tap water or when wastewater was not diluted. At the end of the 22-days experiment, a maximum biomass of 0.8–1.9 g L−1 was reached for algae grown on wastewater. The produced biomass had a high macronutrient content, and the heavy metal content was below maximum limits for use in animal feed. Likewise, the tested pathogen groups were reduced until below safety norms for feed production after algal growth in unsterilized 50% wastewater (diluted with tap water). Overall, these findings add to our growing knowledge on the cultivation of microalgae on wastewater and its valorization opportunities, paving the way for a more sustainable use and reuse of resources.

Integrating Microalgae Cultivation with Wastewater Treatment: a Peek into Economics.

Microalgae cultivation on wastewater is one of the most promising processes in perspective of green and circular economy. This study investigated the economics of integrating the microalgae cultivation with the wastewater treatment in perspective of biomass production and wastewater treatment. The cost of integrated process was evaluated for six cases: three cases for domestic wastewater at different stages of treatment including sewage, anaerobically digested domestic effluent, and centrate and three cases for industrial wastewater including agro-industrial wastewater, anaerobically digested piggery effluent, and anaerobically digested abattoir effluent. The cost of biomass production was found ranging from $ 0.39 to $ 0.92/kg with minimum for the anaerobically digested domestic effluent and centrate. The cost of wastewater treatment was found ranging from 0.18 to 1.69/m3 with minimum for the sewage. These costs did not include any credits generated from the biomass or the treated wastewater. The concentration of limiting nutrient, flowrate of wastewater, and the extent of nutrient removal are the major cost-influencing parameters for the integrated process.

ASSESSMENT OF ECOLOGICAL AND ECONOMIC EFFICIENCY OF COMPOSITE FUEL PRODUCTION FROM THE PEAT AND BIOMASS

The goal of investigation was assessment of environmental impact and economic efficiency of composite briquette production on the base of peat and renewable biomass. Biomass for composite briquettes was obtained from straw (cereal crops and rape) and wood residues (sawdust, chips) Experimental composite briquette were produced from the mixture of peat and biomass in relation to – 25 : 75, 50 : 50, 75 : 25. The technological cards of biomass feedstock production for 6 variants were developed. Technological cards were used for calculation of emission into the atmosphere during life cycle of biomass production and prime cost of biomass. The lowest volume of gas (SO2, NOx, CO2)
 and particulate matter (PM) emission was installed for biomass production from the sawdust. The highest volume of
 emission was installed for production of biomass from the straw with pressing it in standard bale. The volume of CO2
 emission for the sawdust production was 6 kg per ton of biomass and for the standard bale of straw was 19 kg per ton of
 biomass. Prime cost of sawdust production (lowest) was 11 belarusian rubles per ton of biomass, for the wood chips was 19 rubles per ton and for the straw varied from 26 to 33 rubles per ton in depend of technology. It was installed that
 growth of biomass rate in composite briquette had a good influence on number of basic fuel characteristics (contents of
 ash, sulfur and moisture). The variation of calorific value of briquette was not significant in depend of biomass contents.
 In accordance with assessment of all characteristics the better briquettes was obtained from the peat and sawdust.

The Role of Heterotrophic Microalgae in Waste Conversion to Biofuels and Bioproducts

In the last few decades, microalgae have attracted attention from the scientific community worldwide, being considered a promising feedstock for renewable energy production, as well as for a wide range of high value-added products such as pigments and poly-unsaturated fatty acids for pharmaceutical, nutraceutical, food, and cosmetic markets. Despite the investments in microalgae biotechnology to date, the major obstacle to its wide commercialization is the high cost of microalgal biomass production and expensive product extraction steps. One way to reduce the microalgae production costs is the use of low-cost feedstock for microalgae production. Some wastes contain organic and inorganic components that may serve as nutrients for algal growth, decreasing the culture media cost and, thus, the overall process costs. Most of the research studies on microalgae waste treatment use autotrophic and mixotrophic microalgae growth. Research on heterotrophic microalgae to treat wastes is still scarce, although this cultivation mode shows several benefits over the others, such as higher organic carbon load tolerance, intracellular products production, and stability in production all year round, regardless of the location and climate. In this review article, the use of heterotrophic microalgae to simultaneously treat wastes and produce high value-added bioproducts and biofuels will be discussed, critically analyzing the most recent research done in this area so far and envisioning the use of this approach to a commercial scale in the near future.

Climate-Simulated culturing suggests high microalgal biomass and oil productivities in most of the South American continent.

Current production costs of microalgal biomass indicate that only highly-productive cultivation facilities will approach commercial feasibility. Geographical site selection for siting those facilities is critical for achieving target productivities. The aim of this study was to provide a semi-empirical estimation of microalgal biomass and lipids productivity in South America. Simulated-climate was programed in environmental photobioreactors (Phenometrics) for a simulation of cultivation in open raceway ponds at different geographical sites. The mean annual South American biomass productivity of 20-cm deep ponds was 12 ± 4g · m- 2 · d-1 . The most productive regions were clustered in the subtropical and tropical regions of the continent. Fortaleza (Brazil) showed a low seasonality and a high annual mean productivity of 23g · m-2 · d-1 in 5-cm deep ponds, closely approaching the productivity target. Lipids accumulation and productivity in Fortaleza showed a high microalgal oil accumulation up to 46% (w/w) and a maximum oil productivity of 5g · m-2 · d-1 for biomass containing around 20% lipids (w/w). This study provides the first semi-empirical estimation of microalgal productivity in South America and supports a high potential of a vast region of the continent.

Evaluating the effects of geometry and arrangement parameter of flat panel photobioreactor on microalgae biomass production and economic performance in China

In the present study, a model integrated algal biomass productivity prediction and economic analysis for flat panel photobioreactor (PBR) was proposed. The effects of PBR geometry dimension and spacing distance on culture temperature, biomass productivity and production cost were assessed. The simulation results showed that geometry dimension and arrangement parameter of flat panel PBR have a significant impact on algal biomass productivity and production cost. The biomass cost ranged from 2.82 $ kg−1 to 25.07 $ kg−1 was estimated in the different design scenarios, corresponding to biomass productivity of 10.13–36.70 t ha−1 yr−1. The minimum biomass cost of 1.68 $ kg−1 was further predicted by integration of increasing biomass productivity, free carbon dioxide adoption, and thermo-tolerant strain used without cooling action. Additionally, it was also found that the biomass production cost estimated in the present work was lower than those previously reported, which is partially attributed to the lower electricity and labor cost in China. In all, the model framework proposed here can help to optimize the layout design of PBR system in various geospatial locations to achieve cost-effective production of microalgae.

Techno-economic analysis of microalgae related processes for CO2 bio-fixation

The current need to reduce greenhouse gas emissions is pushing the incorporation of technologies to achieve industrial decarbonisation in Europe. The present work develops a techno-economic tool that analyses different scenarios to assess microalgae production in some foreseeable situations, and determines the ones in which the contribution of CO2 biofixation would be relevant. The biomass production cost ranged between 0.41 and 13.06 €/kg. It was also possible to recover 0.03–0.1 €/kg CO2 depending on its temporal variation and the amount of biomass produced. This analysis aims to identify the technologies and operational conditions viable for the different applications. According to the scenarios considered, microalgae technology could be competitive if the emission rights market reaches expected costs of approximately 50 €/t CO2 in the near future (2030). Otherwise, microalgae related processes can be also reliable for different medium- and high-value applications, but only if adequate technologies and operational conditions are considered. The information here provided supports decision making processes for microalgae based processes.