IFP School

2015

Microalgae : A promising source of fuel for mobility PSM ENERGY TRANSITION

Groupe 4 Adrien HANKUS France CHAMPENOIS Wahyuningrum LESTARI Maxime MOULINEY Kenneth YEOH

1

Table of Contents

Executive summary ............................................................................................... 2

Introduction ......................................................................................................... 3

Microalgae for biofuel ........................................................................................... 4 Context of biofuel .............................................................................................................................................. 4 What is microalgae? ......................................................................................................................................... 4 How to grow microalgae?.............................................................................................................................. 5

Cultivation. .............................................................................................................................................................. 5 Harvesting. .............................................................................................................................................................. 7 Lipid/Oil extraction. ........................................................................................................................................... 9 Processing. ............................................................................................................................................................. 10

Environmental Impacts ............................................................................................................................... 11

Current Situation ................................................................................................ 12 Projects description ...................................................................................................................................... 12 Financial aspects ............................................................................................................................................ 13 Hypothesis used ............................................................................................................................................. 14 Sector of improvements .............................................................................................................................. 15

Scenario 2030 ..................................................................................................... 16 Hypothesis on potential gains process efficiency or cost ............................................................. 16 Results ................................................................................................................................................................ 18

Conclusion .......................................................................................................... 18

References .......................................................................................................... 20

Appendix ............................................................................................................ 22

2

Executive summary

Excessive uses of fossil fuels and environmental degradation have forced the scientists to find alternative and clean sources of energy. Biofuels are considered as potential alternatives as they are green in nature and are sustainable energy sources. Biodiesel is one of the most commonly used biofuel due to its fuel characteristics. Several feedstocks can be used to produce biodiesel. However, in recent years, microalgae have emerged as potential biodiesel feedstocks. Microalgae are considered as the 3rd generation biofuel for mobility. Potential has been proven, but economical and industrial scale application remains limited. Critical factors affecting the biodiesel production process including species isolation, species selection, cultivation, harvesting, and oil extraction are discussed. Current research, barriers and developments concerned to each step of biodiesel production process are summarized. New ideas are proposed to improve the growth rate, lipid contents and harvesting efficiency of microalgae. To assess the economic viability of microalgae oil, an economic analysis is presented. Future research trends are also discussed. This study aims to evaluate potential development of the value of this green alternative for the near future, 2030.

Current analysis show that microalgae biofuels are not a feasible alternative, but with overall progress in key sectors, our future projection leads to a more positive picture of biofuel integration in the global energy mix for 2030. At the end of the report, a summary of prices are listed according to our scenarios.

3

Introduction

As global demand for energy continues to rise, carbon dioxide emissions are expected to reach new record high, increasing from 31 Gt in 2011 to approximately 37 Gt in 2035 (IPCC, 2013). The need for climate change adaptation and the growing concerns over energy security are the main drivers behind the policies of many countries (belonging to the Organisation for Economic Co-operation and Development (OECD)) that encourage the growth of renewable energy. Today, renewable energy contributes 13% of the total global energy consumption, in which bioenergy accounts for approximately 10%. Bioenergy refers to the energy content in solid, liquid and gaseous products derived from biological raw materials (biomass) (IEA, 2010).

World primary demand in 2011 and New Policies Scenario

Excessive uses of fossil fuels and environmental degradation have forced the

scientists to find alternative and clean sources of energy. Biofuels are considered as potential alternatives as they are green in nature and are sustainable energy sources. Biodiesel is one of the most commonly used biofuel due to its fuel characteristics. Several feedstocks can be used to produce biodiesel. However, in recent years, microalgae have emerged as potential biodiesel feedstocks. Microalgae offer advantages over conventional feedstocks. Microalgae have ability to fix atmospheric CO2 and convert it into sugars, which are then converted into fuel after biochemical processing. Microalgae have high growth rate and accumulatelipids up to 70% in their cell body. They demand less water and nutrients for their growth as compared to terrestrial crops. Despite these advantages, the scale-up applications of microalgae biofuels have some technical limitations.

4

Microalgae for biofuel

Context of biofuel

Biofuels for transport represent the major fraction of bioenergy production worldwide. Biofuels are primarily produced from food crops with high content of sugar and starch, such as corn and sugarcane to produce ethanol, and oil seeds to produce biodiesel. These first generation technologies have been the first significant step of transition away from the traditional fossil fuels. It has then moved forward to the next generations of biofuels produced from non-food biomass, including residues of crops or forestry production (e.g. forest thinning, sawdust, etc.), dedicated energy crops (e.g. switchgrass, poplar, and miscanthus), lignocellulosic fraction of municipal and industrial solid waste, and algal biomass. More than two-thirds of bioenergy comes from the first generation land-based feedstocks, leading to growing concerns over competition for land and water for food and fibre production and other environmental issues related to land-use changes. Therefore, the use of residues and wastes for bioenergy production has attracted more interest as they are often readily and locally available in most of the countries. Potential of lignocellulosic biomass varies and depends on the type, abundance and cost of biomass feedstocks, efficiency of the available processing technologies, and the pattern of energy demand.

As noted earlier, biodiesel production from 1st and 2nd generation feedstocks have some ethical and sustainability issues. Recently, the most promising choice for biodiesel production is microalgae. Microalgae have advantages over other feedstocks. Microalgae have high photosynthetic efficiency than terrestrial crops. They grow 100 times faster than other plants. Microalgae have ability to use atmospheric CO2 as a carbon source. They can fix CO2 at higher rate than other plants. Microalgae fix CO2 and convert it into value added products such as vitamins, lipid, protein, bio-ethanol, and bio-hydrogen.

What is microalgae?

Micro-algae are a large and diverse group of aquatic organisms that lack the complex cell structures found in higher plants. They can be found in diverse environments, some species thriving in freshwater, others in saline conditions and seawater. Most species are photoautotrophic, converting solar energy into chemical forms through photosynthesis. Micro-algae have received considerable interest as a potential feedstock for biofuel production because, depending on the species and cultivation conditions, they can produce useful quantities of polysaccharides (sugars) and triacylglycerides (fats). These are the raw materials for producing bioethanol and biodiesel transport fuels. Micro-algae also produce proteins that could be used as a source of animal feed, and some species can produce commercially valuable compounds such as pigments and pharmaceuticals.

To go further into details, microalgae are unicellular organisms, which can measure from 1 to 10µm and are spread over 50 000 species (300 have identified

5

useful for biofuel production). They use to live in aquatic environment where they are able to grow very fast: several divisions per day can be performed in favorable conditions. Microalgae have the advantage to contain up to 80% of lipid/oil (on average from 20 to 50%). They can also grow on non-farmlands at all seasons with a high productivity factor compared to 1st and 2nd generations.

Crop Production (L/ha)

Corn 172

Soya 446

Palm oil 5950

Microalgae 20 000 – 60 000

How to grow microalgae?

The growing process might be split in several steps as shown in the following chart, and will be develop in this following part.

Cultivation. Like plants, algae use the sunlight for the process of photosynthesis. Photosynthesis is an important biochemical process in which plants, algae, and some bacteria convert the energy of sunlight to chemical energy. Algae capture light energy through photosynthesis and convert inorganic substances into simple sugars using the captured energy. There are two main ways for algae cultivation.

o Open pond – raceway pond They can be cultivated in open ponds & lakes. The CO2 is obtained by air, but to

enhance productivity, submerged CO2 aerators may be use. They are actually the cheapest middle to make algae growth, but the conditions are less controlled. The typical production rates reach around 25 g/m²/day of biomass (if the conditions are good!).

6

o Closed pond – Photobioreactor (PBR) The aim for PBR is to control the conditions. Thus, PBR are often thin to maximize

light distribution. Cycle on dark and shine period can be used too. They need a pump for O2. To mix, they often use bubbles of CO2 that also provide that gas. The average of production rates is around 30 g/m²/day of biomass, but with less risk of contamination and controlled conditions (T°, pH, light and light frequency, O2 concentration, …). 3 types of PBR mainly use: bubble columns (~0,4 g/L/day, 110 WMm3), flat plates (~0,75 g/L/day, 150 W/m3) and tubular reactors (~0,5 g/L/day, 300 W/m3).

In this table are summarized and compared the open ponds and the closed one.

Open pond Photobioreactor

Advantages Advantages

Cheaper to build and operate Overcome the limitations of open pond

Lower energy imput Controlled conditions Durability higher Higher production Maintence Cheaper harvesting

Weaknesses Weaknesses

Exposed to contamination Expensive and using a lot of energy

o Heterotrophic The heterotropic systems use other nutriments and organic carbon source

instead of CO2 to grow. The most known example is wastewater, allowing reducing the nutrient level (in treated wastewater…). This would decrease harvesting cost and increase lipid production (figures). One other advantage is that it reduces the need in fresh water. This technique can be easily imagined in our cities, underground for example. In the table are listed the strong and weak point of this method.

Photographic Heterographic

Advantages Advantages

Cheap No need of light Hight growth rate Low capital investment Lower chances of contamination High lipid yield Less fresh water

Weaknesses Weaknesses

7

High capital investment Expensive Lower lipid yield Slow growth rate Need light Contamination

Harvesting. The harvesting of microalgae biomass is a critical step in the production of

biofuels from microalgae, because it determines the final quality of extracts, and energy inputs, and therefore overall sustainability, and it also prevents fouling of the production process. It accounts for the highest component of the total cost of microalgae biomass production. High costs are related to the low cell densities (typically in the 0.3–0.5 g L−1 range) and small size of microalgae cells (typically <40 μm).

The selection of appropriate harvesting techniques is therefore critical to economic and environmentally sustainable harvesting.

Factors such as strain, cell density, culture condition, growth media and value of target products determine both the cost of and ease of harvesting. Appropriate harvesting unit process should be able to: maximize the recovered biomass dry weight (varies with microalgae species, biomass concentration and cell sizes), minimize the cost of operation and maintenance (including energy consumption), and yield quality extracts. Here is a list of different way of harvesting :

o Flocculation This process aggregates the microalgal cells to increase the overall cluster sizes,

and is generally used as a preparatory step for other harvesting methods. It involves the addition of multivalent cations and cationic polymers to the culture medium to neutralise the negative charge that is carried on the surface of many microalgal cells.

o Flotation Dissolved air flotation (DAF) process injects micro-air bubbles into the culture

column, and as they rise to the surface, they trap microalgae cells and move them upwards.

Advantages are moderate cost, low space requirement and rapid operation compared to other processes. On the other hand, the main disadvantage might be the technical viability.

o Sedimentation One of the most commonly used harvesting processes because of its capability to

handle large volumes of culture, and suitability for low-value biomass. It can only be applied to species with large cell size (>70 μm) like Spirulina.

Advantages: non-fouling technique therefore can be used for food-grade products, it can be operated continuously without inducing shear stress on the microalgae cells which causes cell destruction and it’s a rapid process.

8

Disadvantage: energy-extensive which makes it unsuited to harvesting biofuel-directed algae biomass, but it may be more economic in large scale production systems.

o Filtration Conventional filtration processes with micro-strainers or rotating screen filters

with backwash may be the most appropriate for harvesting of large cell algae (>70 μm) such as Spirulina. This method is not applied on species with small dimensions.

Membrane filtration and ultra-filtration are alternatives for the recovery of smaller and more fragile microalgae cells (<30 μm). The latter is a more expensive process because of the need for membrane replacement and pumping.

o Cell immobilization This process prevents cells from moving independently of its neighbors to all

parts of the aqueous phase of the system. More research is needed on the effects of immobilization on algal cell physiology and biochemistry.

o Thermal drying Drying is sometimes required after the harvesting steps to prevent fouling of the

final biomass product. Different types of drying: un-drying (most popular method due to low cost, but long drying times and requirement for large surface areas and high material loss), low-pressure shelf-drying, freeze-drying and spray-drying (expensive and used for high-value products and oils), drum-drying and fluidized bed-drying. Table: Barros et al. (2015)

9

Lipid/Oil extraction. In order to produce biofuel, extraction of the oil (or lipid) present in the cell is a

main step in the process. Several methods are developed.

o Oil presses This technic is commonly used to extract oil from nuts and seeds. Same equipment and process can be used to extract oil from microalgae. In order for this process to be effective, algae must first need to be dried. Press uses pressure to break cells and compress out oil. Although this method extracts almost 75% of oil and no special skills is required, this method was reported less effective due to comparatively longer extraction time.

o Hexane Solvent Method Algal oil can be extracted using chemicals. Benzene and ether have been used,

but a popular chemical for solvent extraction is hexane, which is relatively inexpensive. The downside to using solvents for oil extraction are the inherent dangers involved in working with the chemicals. Benzene is classified as a carcinogen. Chemical solvents also present the problem of being an explosion hazard. Hexane solvent extraction can be used in isolation or it can be used along with the oil press/expeller method. After the oil has been extracted using an expeller, the remaining pulp can be mixed with cyclo-hexane to extract the remaining oil content. The oil dissolves in the cyclohexane, and the pulp is filtered out from the solution. The oil and cyclohexane are separated by means of distillation. These two stages (cold press & hexane solvent) together will be able to derive more than 95% of the total oil present in the algae.

o Supercritical Fluid Extraction It is one of the promising green technology methods, which has the potential to

displace the traditional organic solvent lipid extraction methods. A typical extraction unit consists of a feed pump for compression and transportation of liquid CO2 to the extraction vessel, which is installed inside an oven module, and a heated micro-metering valve to depressurize incoming SC-CO2. Once the oven is heated, the compressed CO2 enters the heated oven, in a supercritical state and extracts lipid from the microalgae. Once completely decompressed, CO2 evaporates as gas to the ambient, and forces the extracted lipid to precipitate out and collect in the adjoining glass vial. Supercritical carbon dioxide has high solvating power and low toxicity. Intermediate diffusion/viscosity properties of the fluid lead to favorable mass transfer equilibrium and this process produces solvent-free extract. High infrastructure and operational cost associated with this process are its main disadvantages.

o Ultrasound Another promising apparatuses to be used in extraction of microalgae is via

ultrasound. This method exposes algae to a high intensity ultrasonic wave, which creates tiny cavitation bubbles around cells. Collapse of bubbles emits shockwaves, shattering cell wall thus disrupting latter and releasing desired compounds into

10

solution. Extraction can be over 90% of fatty acids. It was proved that ultrasonic increased extraction rate thus affected recovery of lipid extracts. Although extraction of oil from microalgae using ultrasound is already in extensive use at laboratory scale, but sufficient information on feasibility or cost for a commercial-scale operation is unavailable. This approach seems to have lot of potential, but more research is needed to be done.

Processing. There are some techniques to produce biodiesel such as micro emulsion,

pyrolysis, and transesterification with several kind of catalysis. Those methods are to develop and improve vegetable oil properties in order to approximate the properties of diesel fuels. It has been remarked that high viscosity, low volatility and polyunsaturated characters are the mostly associated problems with crude vegetable oils and supposed to be improved.

o Dilution (Direct Blending) and Micro Emulsion Crude vegetable oils can be blended directly or diluted with the diesel fuel to

improve viscosity. Dilution reduces the viscosity, engine performance problems such as injector coking, and more carbon deposits. Generally vegetables oils are diluted with diesel, this method does not require any chemical process. However, dilution is not suitable for long term use in a direct injection engine. Several researches showed that direct use of vegetable oils and their blends have been considered to be difficult to use in both direct and indirect diesel engine. Micro emulsion is another approach to reduce the viscosity of vegetable oils. It is defined as a colloidal equilibrium dispersion of optically isotropic fluid microstructure with dimensions generally into 1–150 nm range formed spontaneously from two normally immiscible liquids and one and more ionic or more ionic amphiphiles (Schwab et al., 1987). To solve the problem of the high viscosity of vegetable oils, microemulsions with solvents such as methanol, ethanol and 1-butanol have been studied by many researchers. Many researchers shown that short term performances of both ionic and non-ionic microemulsions of aqueous ethanol in soybean oil were nearly as good as that of No. 2 diesel, in spite of the lower cetane number and energy content. The durabilities were not determined.

o Pyrolisis (Thermal Cracking) Pyrolysis is a method of conversion of one substance into another through heating or heating with the aid of the catalyst in the absence of air or oxygen. It involves heating in the absence of air or oxygen and cleavage of chemical bonds to yield small molecules. The material used for pyrolysis can be vegetable oils, animal fats, natural fatty acids and methyl esters of fatty acids. The liquid fuel produced from this process has almost identical chemical components to conventional diesel fuel. Many investigators have studied the pyrolysis of triglycerides to obtain suitable fuels for diesel engine. It has been observed that pyrolysis process is effective, simple, wasteless and pollution free (Singh SP and Singh D., 2010). According to Sharma et al. (2008), pyrolysis of the vegetable oil can produce a product that has high cetane number, low viscosity, acceptable amounts of sulfur, water and

11

sediments contents, acceptable copper corrosion values. However, ash contents, carbon residues, and pour points were unacceptable.

o Transesterification Transesterification (also called alcoholysis) is the reaction of a fat or oil with an alcohol to form esters and glycerol. Among the alcohols that can be used in the transesterification reaction are methanol, ethanol, propanol, butanol, and amyl alcohol. Methanol and ethanol are used most frequently. However methanol is preferred because of its low cost. A catalyst is usually used to improve the reaction rate and yield. Because the reaction is reversible, excess alcohol is used to shift the equilibrium to the product side. It also gives glycerol as a byproduct which has a commercial value. Transesterification is the most viable process adopted known so far for the lowering of viscosity and for the production of biodiesel. Thus biodiesel is the alkyl ester of fatty acids, made by the transesterification of oils or fats, from plants or animals, with short chain alcohols such as methanol and ethanol in the presence of catalyst and glycerin is consequently a by-product from biodiesel production.

Environmental Impacts

The craze for microalgae which in currently rapidly developing aims at delivering many environmental benefits compared to the existing biofuel technology. Whereas several issues have to be overcame. The following table lists both positive and negative impacts of microalgae.

Aquatic impacts : o Microalgae have been proved to be effective at recovering a range of compounds from

wastewater, demonstrating a potential as a water clean-up method. o Treatment of water could lead to bioaccumulation of excess nutrients and potentially

toxic compounds including PAHs, PCBs, hormones, oils, etc. However, uncontrolled cultivation could lead to blooms, and disease or pest could lead to population crashes leading to loss of product and clean-up operations being required.

Atmospheric impacts : o Microalgae offer a method for biofixation of carbon dioxide. CO2 could be sequestered

directly from the atmosphere and from flue gases, providing a gas clean-up method too.

o Biogenic emissions have been observed from microalgae including isoprenes, terpenes and organohalogens. Research into the scale of these fluxes is in the early stages of development, but must be continued as these compounds are precursors to ozone destruction and low level ozone formation.

o Location of cultivation sites should be assessed based on other local sources of emissions, as combinations of pollutants could lead to formation of secondary organic aerosols.

Terrestrial impacts :

12

o Microalgae could potentially reduce the demand for fertile land because production systems have much lower land quality requirements than other bioenergy activities, such as biofuel crop production.

o No evidence of research into the indirect land use change impacts of microalgae cultivation has been found (impacts on biodiversity, environment equilibrium, soil erosion …).

Energy demand : o Energy requirements depend on the cultivation technique, which has a direct impact on

the energy balance of the system.

Genetic modification : o Ongoing research into genetic modification of algae could lead to species more suitable

for biofuel production. o Concerns about how modified strains would affect natural strains if released into the

environment remain.

Current Situation

Projects description

At the time of this review, it is important to note that the facts and figures listed are part of a non-exhaustive study. Rigor and precision have been taken by members of the research team in order to maintain as much accuracy as possible in the imparted time. In this review, we will strive to paint a global picture of the current state of microalgae based biofuels and derivatives. Facts and figures come largely from previous studies, themselves based on data from specific, small installations. Validation and cross-checking steps were necessary in order to omit unrealistic case figures. Key issues surrounding the development of industrial size will be presented in this study, in order to shed some light on possible ameliorations and valorization of by-products and or co-products. A certain number of hypothesis on the possible improvement of algae to energy pathways will be emitted.

A review of existing projects lists over a hundred projects running all over the globe. However, the most advanced phase encountered during literature review are those of medium scale pilots. No full scale industrial project exists at the time of this study.

Geography and growing conditions show that suitable climatic zones for the cultivation of algae are located mostly between 37° N / 37° S latitudes. Potential yield is highest in warmer countries, due to presence of sunlight and optimal temperature range for growth. However, strategies have also been developed for colder climates that optimize year round production. Accordingly, many developing countries, particularly in South Asia, the Middle East and the African continent are potential suitable locations for large scale cultivations. The following is a table of current algae oil producing countries (pilot/demonstration phase).

13

Region Asia Europe Americas Oceania

Country Korea China India Iran Israel

Bulgaria

France

Italy

Portugal

Spain

The Netherlands

Finland

Latvia

Argentina Canada Mexico USA Brazil

Australia New Zealand

Traditionally, companies working in the renewable biofuel industry started

with 1st and 2nd generation biofuel research. Many companies have since started to specialize and some cases focus solely in 3rd generation biofuels, notably those of algal origins. Many of the latter are based in countries or stable global and socio-political regions of the world, where government support and industrial potential help drive the development algae to energy efforts. Some of the companies making waves in the sector are Solazyme, Fortum, Fermentalg, Seambiotic, Synthetic Genomics and many others.

In recent years, the vast majority of algae based biofuel development has been led by industrialized nations, but the greatest raw potential exists in developing countries. Brazil, Korea and the Asian region has been vastly developing the biofuel supply market. Many new companies or R&D ventures are being formed with the support of traditional fossil fuel companies; the Oil & Gas industry majors such as Shell, Chevron and ExxonMobil who have invested significant funds into the future of such biofuels.

Financial aspects

Commercial, large scale productions of biofuels are yet to take place at the current time. This leaves a non-negligible uncertainty to existing estimates. This is further compounded when extrapolating to developing countries, as the majority of studies are focused on European or US studies. However, an increasing amount of studies are reporting production technical and economic viability by 2030 – 2040. Considering the high variability of fuel prices, developing alternate fuel sources, in this case algae could provide greater energy stability. In is interesting to note that the price of algal biofuel, albeit inevitably higher than fossil fuels, are intrinsically linked to the latter. The current biodiesel: diesel ratios vary between 4 -7 x. Given this relation, in order for biofuel prices to stabilize, a significant amount of fossil fuels need to be displaced.

Attempts have been made in several studies to estimate the direct cost of algae biofuel production. Final results vary but the general conclusions converge: algae biofuel will remain uncompetitive unless greater progress in all constituting fields is achieved. Key issues surrounding this progress are summed up in the next section, where baseline hypothesis is enumerated for the current situation.

14

Finally, environmental and social impact of the development of algal fuels must be acknowledged. Although 3rd generation biofuels eliminates several concerns from previous generations, but new concerns about arising issues must be proactively debated and resolved. Important issues surrounding this new development are water, liquids and emissions, energy use, overall carbon footprint, soil & land-use, biosecurity issues, social and institutional capacity, policies, regulation and local content growth. If well managed, microalgae biofuels may be a miracle solution, with connotations of wastewater management, environmental benefits, and industrial integration. The opposite being the double edged sword, increased biosecurity/biodiversity risks, and adverse global impacts on socio-economy.

In the following section, we will establish a baseline case for the production of microalgae biofuel. This case will then be extrapolated for the year 2030. In order to facilitate understanding of the situation, a certain number of parameters, their values and hypothesis will be detailed for the reader.

Hypothesis used

o Daily production for algae In a biodiesel point of view, we are especially focused on the lipid production.

Production and yield of lipids ranges between 10 to 300 mg/L/day with optimal yield and productivity range (42-48 g.m-2day-1) & average productivity around 25-30 g.m-2day-1Assuming a dry weight percentage of 20 - 30% for lipids, 40 - 70% for proteins and 15 - 30% for glucides, we can thus find mean values for proteins and glucides. For the baseline case, we will consider a mean value of 25 % lipids.

o OPR vs PBR, hybridization? The growth system plays on the growth rate. As noticed earlier, 2 systems occur:

the open pond reactor (OPR) and the photobioreactor (PBR). In good conditions, the OPR yield rate is 30 mg/L/day of lipids. For the PBR, it can reach a yield of up to 280 mg/L/day of lipids (Weifu Lee, 2013). A list of variables was established with data from different specialized articles by Meyer & Weiss (2014), Richardson et al. (2014) and Weifu Lee (2013). This list can be found in the appendix and shows mean costs and values for important parameters important in the production process to create biofuel from microalgae. The latter is merely an example of a potential microalgae production system over a time period of a year. From the summation of exemplary operating costs, a total labor cost can be acquired for both the open (ORP) and closed system (PBR). The ORP system has a total labor cost of approximately 88 001 047 $ per year, while the PBR system has an annual labor cost of 55 042 863 $. It must be mentioned, however, that in the exemplary study case, the used land facility is significantly higher for the ORP than for the PBR system. Additionally, the mean price unit for labor is 4300 $ per year for the ORP system which is lower than the mean annual price unit of 7200 $ for the PBR system. In terms of electricity used for growth and harvesting, the ORP system uses approximately 60 times less energy than the PBR system.

15

Algae

Max Mean Min

Lipid content of algae 70% 30% 15%

Biomass extraction efficiency 98% 95% 80%

Energy consumption (kW/t) 76,9 40 16,5

Total Area (ha) 1200 950 700

Process

Pre-treatment & Extraction efficiency 100% 95% 75%

Energy consumption (kWh ton-1) 500 100 50

Transformation into biodiesel fct(%algal lipid ct) 66,50% 27,75% 13,50%

Residues (including potential co-products) 33,50% 72,25% 86,50%

Sector of improvements

In order to simulate a feasible scenario for 2030, the main sectors of improvement need to be identified. Estimations and previsions can then be made according to the projected growth and optimization of these sectors. Finally, a general summary will conclude the overall viability of microalgae biofuels for the horizon 2030. The main sectors of improvement can be classed into 3 main sectors :

o Technical & Technological

This concerns all technology associated to algae bio-engineering, growth, extraction and transformation technologies. Globally, the problem of algae biofuel is not that of extraction and transformation, but of algae, algae cultivation and overall costs. Progress is needed in the areas of algae technology, optimization of high lipid strains and bio-engineering of resistant, quality algae. One area of particular interest in terms of technological advance is that of the growth system as well. Extraction and transformation technologies of algae to biofuel are nearing optimal efficiency, but this is not the case in for the cultivation and harvesting tech, which are cost heavy and insufficiently efficient for larger scale applications. Technology for efficient use of the by-products, co-products and waste involved must also be developed, in order to fully realize complete valorization of algae

o Societal/environmental

The impact of algae biofuels on the society and the environment must be studied in depth. Scalability studies, biodiversity risks, and other possible uses for microalgae needs to be identified then exploited. This sector is key to putting microalgae biofuels at the forefront of renewable energy development and help improve the

16

economics associated. Better understanding of the risks & obstacles is also crucial for support from the government and the local population.

o Economical

Generally, poor relative economics remain the Achilles’ heel of the microalgae biofuel boom. This sector is intrinsically linked to all the others. Cost-reduction through innovation is a prevalent aspect at every step of the algae to energy pathway.

One specific field however is the valorization of by-/co-products of the biofuel process. Since lipids only represent 30% of the algae, 70% can still be used for other purposes. Currently, microalgae are used for a wide range of high value products, as pharmaceutical, nutritional food, cosmetic, agricultural fertilizer, energy etc. In term of biofuel production (ie biodiesel), leftover residue can still be upgraded or modified for the fabrication of other products. In the table below the final products acquired from different techniques during biodiesel production are listed: Product From step From

technique Method Final product

Cell residue

Extraction Solvent Fermentation + gasification

Bioethanol (+water+CO2+residue_2) (using glucides and proteins)

Methane

- Chlorophyll (4% of cell amount)

Residue_2

Fermentation

Fermentation

Aerobic digestion Methane (+residue_3) (for energy prod)

Residue_3

Aerobic digestion

Aerobic digestion

- Fertilizer

Additional high value end products generated during the biofuel production

available for other industries (e.g. pharmaceutics, cosmetics …), will help spread the overall costs and thus the price of biofuel can be significantly reduced.

Scenario 2030

Hypothesis on potential gains process efficiency or cost

The aim of this part is to make a hypothesis on possible ways to save in cost and other parameter percentages over the coming years. The hypothesis is based on several studied articles, and treats each distinguished step in the bio-products acquisition from algae. The gains are based on the mean values of table describing algae characteristics (see above). This study focuses mainly on biodiesel, because other energies from algae seem less interesting for the moment, therefore, biodiesel seems to hold the most potential as main final product.

Algae account for 1-5% of the production cost. Currently a large amount of algae species are distinguished from which only some are actually studied for their lipids content and growth rate. Further investigation of microalgae could be interesting but not that promising since large studied have already been carried out. Another

17

possibility would be genetically transformed algae, but the cost of the latter should stay lower than the potential gain.

Water used for algae culture holds 20-40% of the operational costs of water. By choosing specific micro-algae that use non-potable water, we can win a lot of money on the water budget (nutrients are included in other parts).

The ORP system design makes up 5-10% of the production. Currently, ORP design is not really considered as domain for improvement, because of its low price compare to PBR. But the design could be further examined to increase algae growth rate, for example by improving sunlight access through the use of white batches, and/or ameliorate nutritional needs with wastewater.

Dewatering and harvest for ORP accounts for 10-30% (in dewatering-harvesting costs). The main problem is the low concentration of algae and the huge losses of water. Some improvements were mentioned earlier and are linked to saving costs and water consumption.

Robustness for ORP holds 10-20% (in production). Because of the external influence, ORP production can dramatically decrease. Looking at the annual production, the mean value of production can reach around 50% for optimal production percentages (just due to sun exposition, neither considering temperature). Depending of the location of the culture and the mix of algae use during the year, a higher rate is reached. By using a more robust algae or more efficient technology, the rate can be significantly increased.

For PBR, the energy consumption during growth phase makes up 20-30% (in operational costs). The main advantage of PBR is the control of growth conditions, but this can inquire large energy consumption. The need for energy and costs can be confined for example by placing reactors in a water basin outdoors. The latter would decrease light and temperature regulation.

Compared to PBR, “Hybridation“ can represent 30-50% of production costs. By mixing the use of ORP for growth and PBR for algae lipid content the need for energy can be reduced as solar energy would be implied for growth and can be lipid production is facilitated.

Oil extraction & downstream processing represent only 0.5-2% of the production percentages. Literature has proven that current existing efficiencies are already quite good (around 95%), but improvements are still under investigation.

Co-products make up 20-40% of the final price. Algae cells contain around 30% of lipid. So, it still has 70% that can be used in other product. By improving the conversion rate we mainly use the residual part. High value products like proteins can be used for other purposes so it is crucial to extract proteins and lipids without them influencing each other. A last point would be the CO2 market resulting from the algae production. The remaining CO2 can be of interest for further reduction of overall costs depending on the regulation of the market which is currently very low.

In this part, we do not explicitly suggest an improvement involving nutrients. However, we have to keep in mind that this factor could be important because the production of phosphorus and nitrogen production are currently too low to supply the chain. It would mean an increase of the price, except if we can limit their needs or find substitute products.

18

Results

To recalculate new prices for our scenario, we used the hypothesis of gains in process, write above. We use 2012 price repartition datas (NREL; Andy Adens & Ryan Davis) as base.

We used the smallest improvement expected and the mean ones. Using the

lowest gain, the price per litter is still high. But this price needs to be compared with the 2030 petrol price. The last forecasts are around 70-100$/b, or between 0.39 and 0.55€ per litter. Thus, we see that in each case, the open pond still the most competitive system, but hybrid systems between ORP and PBR seem to have a lot of interest too, in the way they offer more robustness and gain possibilities.

But a small amount of biodiesel could be use, and reach around 5%, without big impacts on the customers. This amount of bio-energy from micro-algae would increase the petrol price of approximately 0.10€. That would represent an augmentation between 20 and 25% depending petrol price. If we use the mean gains expectation, this percentage falls to 16-21%. With the global warming, we can also assume than governments will low their taxes for bio-energy. So, the biodiesel could be integrated without any impact on users, and a 10-15% of bio-energy from algae in global energy mix can be imagined.

Conclusion

Through extensive literature review and analysis, this study allows the reader to have an overview of the potential of algae biofuels as a future fuel for mobility. General consensus exists about the difficulty for biofuels to impose in the present day due to poor economics and lack of maturity in terms of technology. However, significant progress is being made with the advances technology and R&D. After thorough investigation of the different stages in the algae to energy pathway, criterion and hypothesis for optimizing this potential were established. For an extrapolated scenario for 2030, a study was made by comparing current costs of algae biofuel production against conventional fossil fuel. When comparing the costs of applied parameters and techniques to the cost of the current crude oil, the concept seems infeasible unless minimum recommendations for improvement are achieved. The future of biofuel goes hand in hand with innovation

This study shows that current prices for biofuel production vary lie around 2.60 €/L and 5.4 €/L for ORP and PBR system respectively. Towards 2030, these

unit cost ORP PBR

Growth 42 522

Harvesting 41 27

Transformation 72 27

OSBL equipment 21 27

Land 22 27

Tot 198 630

Biodiesel OP PBR

Price (€/L) 2,599453 5,423452

2012

%age of cost ORP PBR

Growth 37,422 413,424

Harvesting 36,9 27

Transformation 71,64 26,865

OSBL equipment 21 27

Land 22 27

Tot 188,962 521,289

%improvement 4,564646465 17,25571

Price w-o coproducts

improvments 2,480797159 4,487597

Final price (€/L) 1,984637727 3,590077

Low gains 2030

%age of cost ORP PBR Hybrid system

Growth 34,629 379,755 227,853

Harvesting 32,8 27 27

Transformation 70,92 26,595 26,595

OSBL equipment 21 27 27

Land 22 27 27

Tot 181,349 487,35 335,448

%improvement 8,409596 22,64286 46,75428571

Price w-o coproducts

improvments 2,38085 4,195428 2,887755884

Final price (€/L) 1,666595 2,936799 2,021429119

Mean gains 2030

19

prices would lie around 1.66 €/L for the ORP system, 2.93 €/L for the PBR and 2.02 €/L for a hybrid system.

For 2030, if crude oil prices remain stable in the range of 70-100$/bbl, we estimate that the minimal recommended gains in biofuel technology can be attained. This provides incentive for countries worldwide to develop biofuels. Geography and growing conditions show that suitable climatic zones for the cultivation of algae exist. In previous sections we have seen that adopting the right strategy can widely increase the potential geographical spread of algae biofuel cultivation. Therefore, biofuel can be produced in many countries over a wide latitude range.

In this same scenario, with the progress in algae bioengineering and algae to biofuel technologies, overall costs will be reduced by about 38% to 1.66 €/L in the best case, thus making biofuel a viable and profitable alternative. With the reduction in conventional fossil fuels resources, our estimation puts the part of biofuels in the 2030 energy mix to be around 10 – 15%.

Additionally, optimal valorization of the co-products/by-products can reduce the overall cost of the process. This is a key point in our construction of the 2030 scenario. Social and environmental issues, effluents and wastewater; carbon footprint; biosecurity; and local content are linked to large scale commercial development of biofuels. These issues, although debated in this document, are subject to non-negligible uncertainties, and remains a point to be developed as full scale industrial projects are delivered. We remain optimistic as to the future of microalgae as a source of biofuels, considering ongoing innovation and continuous collaboration of stakeholders towards a common goal.

20

References

- Andersson, V., Broberg, S., Hackl, R., 2011. Program energiesystem: Integrated algae cultivation for biofuels production in industrial clusters. Arbetsnotat 47, pp. 92.

- Baliga, R., Powers, S.E., 2010. Sustainable Algae Biodiesel Production in Cold

Climates. International Journal of Chemical Engineering, 1-13.

- Barros, A.I., Gonçalves, .L., Simo es, M., Pires, .C.M., 2015. Harvesting techniques applied to microalgae: a review. Renewable and sustainable energy reviews 41, 1489-1500.

- Batan, L., Quinn, J., Willson, B., Bradley, T., 2010. Net energy and greenhouse

gas emission evaluation of biodiesel derived from microalgae. Environmental science & technology 44, 7975-80.

- Brentner, L.B., Eckelman, M.J., Zimmerman, J.B., 2011. Combinatorial life

cycle assessment to inform process design of industrial production of algal biodiesel. Environmental science & technology 45, 7060-7.

- Campbell, P.K., Beer, T., Batten, D., 2011. Life cycle assessment of biodiesel

production from microalgae in ponds. Bioresource technology 102, 50-6.

- Clarens, A.F., Resurreccion, E.P., White, M. a, Colosi, L.M., 2010. Environmental life cycle comparison of algae to other bioenergy feedstocks. Environmental science & technology 44, 1813-9.

- Clarens, A.F., Nassau, H., Resurreccion, E.P., White, M. a, Colosi, L.M., 2011.

Environmental impacts of algae-derived biodiesel and bioelectricity for transportation. Environmental science & technology 45, 7554-60.

- Collet, P., Hélias, A., Lardon, L., Ras, M., Goy, R.-A., Steyer, J.-P., 2011. Life-

cycle assessment of microalgae culture coupled to biogas production. Bioresource technology 102, 207-14.

- Collet P., Spinelli D., Lardon L., Helias Q., Steyer J.P., Bernard O. 2013. Life-

Cycle Assessment of Microalgal-Based Biofuels. Biofuels from algae, Elsevier, 287-312.

- Hou, J., Zhang, P., Yuan, X., Zheng, Y., 2011. Life cycle assessment of biodiesel

from soybean, jatropha and microalgae in China conditions. Renewable and Sustainable Energy Reviews.

- Jorquera, O., Kiperstok, A., Sales, E. a, Embiruçu, M., Ghirardi, M.L., 2010.

Comparative energy lifecycle analyses of microalgal biomass production in open ponds and photobioreactors. Bioresource technology 101, 1406-13.

21

- Kadam, K.., 2002. Environmental implications of power generation via coal-

microalgae cofiring. Energy 27, 905-922.

- Khoo, H.H., Sharratt, P.N., Das, P., Balasubramanian, R.K., Naraharisetti, P.K., Shaik, S., 2011. Life cycle energy and CO2 analysis of microalgae-to-biodiesel: preliminary results and comparisons. Bioresource technology 102, 5800-7.

- Lardon, L., Hélias, A., Sialve, B., Steyer, J.-P., Bernard, O., 2009. Life-Cycle

Assessment of Biodiesel Production from Microalgae. Environmental Science & Technology 43, 6475-6481.

- Liandong Zhu L., Ketola T. 2012. Microalgae production as a biofuel

feedstock: risks and challenges. International Journal of Sustainable Development & World Ecology, 19(3), 268-274.

- Meyer, M.A. and Weiss, A., 2014. Life costs for the optimized production of

hydrogen and biogas from microalgae. Energy 78, 84-93.

- Moody, J.W., McGinty, C.M., Quinn, J., 2014. Global evaluation of biofuel potential from microalgae. PNAS 111(23), 8691-8696.

- Richardson, J.W., Johnson, M.D., Zhang, X., Zemke, P., Chen, W., Hu, Q., 2014.

A financial assessment of two alternative cultivation systems and their contributions to algae biofuel economic viability. Algal Research 4, 96-104.

- Sander, K., Murthy, G.S., 2010. Life cycle analysis of algae biodiesel. The

International Journal of Life Cycle Assessment 15, 704-714.

- Slade R., Bauen A. 2013. Micro-algae cultivation for biofuels: cost, energy balance, environmental impacts and future prospects. pp. 28.

- Stephenson, A.L., Kazamia, E., Dennis, J.S., Howe, C.J., Scott, S. a., Smith, A.G.,

2010. Life-Cycle Assessment of Potential Algal Biodiesel Production in the United Kingdom: A Comparison of Raceways and Air-Lift Tubular Bioreactors. Energy & Fuels 24, 4062-4077.

- Weifu Lee, J., 2013. Advanced biofuels and bioproducts. Springer

Science+Business media New york, pp. 1122.

- Yang, J., Xu, M., Zhang, X., Hu, Q., Sommerfeld, M., Chen, Y., 2011. Life-cycle analysis on biodiesel production from microalgae: water footprint and nutrients balance. Bioresource technology 102, 159-65.

- Zaimes G.G., Khanna V. 2013. Microalgal biomass production pathways:

evaluation of life cycle environmental impacts. Biotechnology for Biofuels, 6(88).

22

Appendix Investment cost items & parameters for an exemplary production system over a year time period

Production Equipment Mean price per unit currency Mean capacity unit

Photobioreactor 103 eur 0,025 m3

culture medium preparation unit 6000 eur 4 m3/h

culture medium feed pump 6000 eur 12,5 m3/h

CO2 supply station 2585,16 eur 27,4 kg/h

Cooling system 21,5 eur 1 m2 heat transfer area

Pump for cooling system 6000 eur 12,5 m3/h

Centrifuge 183000 eur 22 m3/h

Centrifuge feed pump 6000 eur 12,5 m3/h

storage compressor 497080 eur 2 Mpa

high-pressure storage 785180 eur 1200 kg H2/h

Total production costs PBR 1491969,66 eur

Total production costs ORP 12000 eur

Other investments for an exemplary production system over a year time period

parameter Mean percentage

buildings 30% of equipment costs 447590,898 eur

control unit 15% of equipment costs 223795,449 eur

piping 20% of equipment costs 298393,932 eur

installation costs 30% of equipment costs 447590,898 eur

cost of capital 3,40% of investment

Major parameters for an exemplary production system over a year time period

parameter Mean value unit

net production area 1 ha

land area 1,3 ha

operation days PBR 252 d/y

lifetime PBR and technical equipment 10 y

lifetime PBR and concrete works 20 y

harvesting electricity cost 395 kWh/ton biomass

extraction electricity cost 750 kWh/ton biomass

personnel for PBR operation 3 FTE

biomass required per batch 757,5 t for PBR

947,5 t for ORP

biomass extracted per batch 606 t for PBR

758 t for ORP

biomass concentration 4,52 kg/m3 for PBR

0,58 kg/m3 for ORP

Total cultivation area 5284365 m2 for PBR

8098291 m2 for ORP

23

Total area 7047680 m2 for PBR

10797721 m2 for ORP

Cultivation areal productivity 0,036 kg/m²/day for PBR

0,023 kg/m²/day for ORP

Total areal productivity 0,027 kg/m²/day for PBR

0,018 kg/m²/day for ORP

Volumetric productivity 1,131 kg/m3/d for PBR

0,117 kg/m3/d for ORP

Volume per cultivation unit 30 m3 for PBR

210 m3 for ORP

Total volume 167403 m3 for PBR

1619658 m3 for ORP

Approximate annual CO2 assumption 92000 t for PBR

92000 t for ORP

Operating costs for an exemplary production system over a year time period

LABOR

Mean price per unit currency unit

ORP non-harvesting & extraction labor 4300 $ ha-1 for 27350 ha

PBR non-harvesting & extraction labor 7200 $ ha-1 for 5730 ha

Dissolved air flotation labor 120 000 $ yr-1 for ORP

60 000 $ yr-1 for PBR

Centrifuge labor 60 000 $ yr-1 for ORP

60 000 $ yr-1 for PBR

Membrane ultrafiltration labor 60 000 $ yr-1 for ORP

60 000 $ yr-1 for PBR

Sub-hydrothermal pretreatment labor 120 000 $ yr-1 for ORP

120 000 $ yr-1 for PBR

Lipid extraction and solvent recovery labor 120 000 $ yr-1 for ORP

120 000 $ yr-1 for PBR

Lipid fractionation/separation 120 000 $ yr-1 for ORP

120 000 $ yr-1 for PBR

Total ORP labor cost 88 001 047 $ yr-1

Total PBR labor cost 52 042 863 $ yr-1

UTILITIES

Mean value per unit currency unit

water 1,65 eur m3

fertilizer N 1050 eur t (pure nutrient)

fertilizer P2O5 1300 eur t (pure nutrient)

amount of N input 91

kg/t DW algae

amount of P input 22

kg/t DW algae

Electricity 0,11 eur kWh

electricty used for ORP 2471,3184

kwh acre m-1 yr-1

electricity used for PBR 148 882

kwh acre m -1 yr-1

24

Heat 0,04 eur kWh

CO2 184 eur t

CO2 requirement 1,8

t/t DW algae

facility land 500 usd per acre

pond width 70

m

pond length 1000

m

water depth 0,25

m

total tubing length 58925967 m for PBR

N/A

for ORP

OPERATING COSTS

Mean price per unit currency unit

Maintenance PBR related equipment 4 % of equipment costs

Maintenance PBR related equipment 0,5 % of building

Insurance 0,6 % of depreciation

Wastewater discharge 2,36 eur m3