NOTE: This article was originally written in Danish, and has not been translated by any of the authors. However, the translation has been accepted by an author of the article.
This report is written as a task for the Faculty of Life Sciences in October 2008 by stud.scient. Janus Houe Magnussen, Anders Odderup Lundby Madsen and Anne Hess. Citation will be based upon scientific standard and the source (Magnussen et al., 2008).
University of Copenhagen
Faculty of Life Sciences
Biology-Biotechnology
Janus Houe Magnussen, Anders Odderup Lundby Madsen and Anne Hess
Project report
Supervisors: Poul Erik Jensen, Vagn Olsen and Bjarke Veierskov
22. October 2008
"The oil boom is over and will not return ...
All of us must get used to a different lifestyle. "
King Abdullah, Saudi Arabia, 1998.
Resume
Our current consumption of fossil fuels in the transport sector are generally not considered to be sustainable, partly because of dwindling resources and their impact on the environment. There is therefore need for sustainable and CO2-neutral alternatives. Biofuels from agriculture crops (maize, sugar, soy, and so on) is a reusable and CO2-neutral alternative, these alternatives can not replace the current types of fuel. As we see in this report does biofuel from algae as a real alternative because of high yields and low price and that the production of which does not conflict with the current food production. Like land crops using algae sunlight to create biomass, but they are just much better at it than conventional crops. There is thus reason to biofuel derived from algae is a real alternative to conventional fossil fuels for transport.
Contents
1 Problem Analysis
2 Problem Formulation
3 Definition and method
4 General information on algae
5 Cultivation of algae and conditions for optimum growth
5.1 Raceway Ponds
5.2 tubular fotobioreaktor
5.3 Comparison of the two systems
5.4 Locations
6 From soup algae for biofuel
7 By-products
8 Profitability
8.1 Economic
8.2 Environmentally
9 Quality of biofuel from algae
10 The potential for biofuel from algae
11 Discussion.
12 Conclusion.
13 Perspectives.
Bibliography
1 Problem Analysis
The world community today is facing a number of immediate problems. An important of these is a rapidly growing energy consumption. The increased energy consumption is partly due to we become more and more people and that people on average use more energy, including energy in transport. A major problem for oil as our only real source of energy for transport is that it is a strong dwindling resource. There are many different projections for when the oil runs out, and the variation is quite large including but all are agreed that it is an eternal source. A corollary of this strong demand, driven in particular by China's and India's great industrial growth, is the price of fuel rises. Another problem with burning fossil fuels is the damage it causes to the environment. Of environmental damage include particle pollution, which increasingly constitute health hazards especially in large cities, the formation of acid rain through the discharge of sulfur particles (sulfuric acid) and NOx compounds (nitric acid) and CO2 emissions contributing to global warming. Therefore, there is a need to find alternatives to oil production.
We have previously tried it with alternative energy sources, and with success, to a large part of our energy consuming sectors, but especially in one sector lags behind, and this is the aforementioned transport. Alternative energy sources may include mention nuclear power, wind power and solar cells that are good, renewable and CO2 neutral energy sources, but if the energy produced in the form of electricity and therefore not very useful in transport, provided that we continue to drive cars looks like they do now. And just this assumption is relevant in our problem. For one could really rethink our whole way of life so that we lived closer to work, cut down on overall production, etc. but in our project, we work just based on the assumption that we will continue to run in cars and still have a general high productivity. There is in this context, found a number of alternatives, the key is probably different types of biofuels, hydrogen and electric vehicles. Cars running on hydrogen and electricity in the form of a battery is in itself good alternatives, yet there are a number of problems associated with these technologies. Among others, there is the problem that the cars we use today can not directly run on hydrogen or electricity, and the total vehicle fleet was thus replaced. Another and perhaps more significant problem with regard to cars that run on hydrogen is that, in connection with hydrogen production (splitting of water into dihydrogen and oxygen) is used a lot of energy and that this often comes from the burning of fossil fuels. In connection with our project where we will focus on alternative energy to transport and with regard to our assumptions, is that technology is not particularly relevant. Another alternative, biofuel is fuel extracted from biological material that has lived more recently. It is the latter definition is very different biofuels produced from fossil fuels. Biofuels fall into three categories: 1 2 and 3 generation. 1. generation biofuels is an already tested and available technology, we now can find on some stations. The problem with this is that the production of bioethanol using the constituents of crops as we ourselves would eat (eg grains, soybeans, sugarcane, etc.), this competition has received considerable criticism because it will get food prices to rise and create lack of the remaining food (Grundwald, 2008). 2. generation biofuels based on the principle of 1 generation, but this rate instead of the edible parts of the plant to use the inedible (from the example before: plants from maize, soya, sugar cane). Technically, it is harder to extract useful material from these parts, as they exist in the form of cellulose and other persistent materials. Research in this field has advanced, but still missing a piece before it can be used on a commercial level. The latest technology is 3 generation biofuels. This type of fuel derived from algae. The beauty of this technology compared to 2 generation, is that by growing algae does not take up land, because the algae can grow in principle and are grown everywhere (eg in reservoirs in the ocean). In addition, their increasing algae biomass considerably faster than conventional plants used for 1st and 2nd generation biofuels (UN Chronicle, 2000). As it also happened with the 2nd generation biofuels is that technology is far from ready for commercial use, but research so far shows good results (Xiufeng et al., 2007).
There are many different stakeholders in the energy sector as pulling in opposite directions. On the one hand, the OPEC countries, as one might expect would have an interest in a continuation of the current oil dependency. On the other hand, all the other countries which do not produce (enough) oil. While developing countries could benefit from various new forms of energy, if they led to the general fuel price fell it would say if we could produce biofuels at competitive prices.
2 Problem Formulation
As a consequence of increased energy consumption and dwindling oil reserves, says world facing major environmental challenges and an early energy shortage. Particularly, it will be a problem for the transport sector since its energy almost exclusively composed of oil, and this is difficult to directly replace oil as an energy source. As solutions to these problems are a range of alternative energy sources, including 3rd generation biofuels seem to be sensible.
The purpose of this project is to explore what opportunities there are for the production of 3 generation biofuels as replacements for conventional transportation fuels.
· How is the cultivation of algae and transformation into biofuel? How could a plant be built?
• What products are in algal production and transformation?
· What is the future for the 3rd generation biofuels?
3 Definition and method
We will in this report focus exclusively on biofuel from algae (3rd generation biofuels) for transport. In quantity and in terms of replacing conventional transportation fuels we will look at total world transportation energy use.
As a method we will use written sources (mainly scientific articles) and contact the relevant executives from Shell, respectively, Denmark, NERI (National Environmental Research Institute) and AlgaeLink.
4 General information on algae
Picture 1 shows a lysmikroskopisk image of the algae Haematococcus pluvialis (The Fraunhofer Institute for Interfacial Engineering and Biotechnology, 2000).
Algae are a group of eukaryotic, fotoautotrofe organisms that occur either as a single living cell or as complex vegetation, such as seaweed. They live in both saltwater and freshwater, and act as microscopic plants, as plants on land, requires that certain conditions are met so that they can live and multiply. These conditions consist of the set (sun) light, carbon dioxide, water, oxygen and presence of nutrients. Thereby the algae in a position to carry out photosynthesis, resulting in glucose and oxygen. Glucose from photosynthesis is converted via respiration to ATP energy that algae use to grow and reproduce (cell division). ATP'en decompose and are hereby released energy can be used to convert inorganic material to organic material. This allows the algae build up large molecules such as cellulose to cell walls. Nutrients can be, for example phosphates and nitrates. Phosphate supplied mainly from sewage and agriculture, but also from organic material such as fallen leaves. Phosphate is vital to the algae when it is used for construction of DNA, RNA and ATP. Nitrates can, among other things come from agriculture, the majority found in the atmosphere (composed of 79% N). However, only some algae use this nitrate, as only some species are able to convert it using oxygen to ammonia (nitrogen fixation). This is used for building proteins and amino acids.
Algae is naturally occurring and found throughout the oceans, lakes and generally damp places. Microalgae, as we deal with this task, is able to float in the water despite a density slightly higher than water. This is due to be constantly pushed up and around because of currents in the water and also because of their different structure. They constitute one of the primary food sources in the water and it forms the lower part of the food chain. Dietary organic matter, are being exploited by small plankton living in the upper aquifer with planktonic algae. Planktonic animals consume energy from organic matter, thus making the oxygen produced by algae, used, and carbon dioxide, nitrogen and other nutrients released. These substances are then used, inter alia, of the remaining algae (NERI, 1999).
Algiers has, as mentioned earlier, different structure. They can be divided in various species such as green algae and diatoms. Øjealger is a class with more than 500 species of colorless, green or red unicellular algae with flags or. Many of these algae has a øjeplet, as far as we know allows them to orient themselves. Diatoms are nuclear deal organisms. They have the ability to bind the air free nitrogen in special cells heterocytter. The cells are without oxygen, which fixes nitrogen and convert it into ammonia. Diatoms have two shells formed of silicon, through which they can absorb nutrients and excrete waste products. They also contain oil droplets which among other things helps to keep them floating in the water (NERI, undated).
Unlike in our project is algae often seen as a major problem. They are major contributors to oxygen depletion in lakes, estuaries and seas. This happens due to a combination of natural algal blooms and an increasingly unnatural inputs of nutrients (Hänselt, 2006). The algae multiply rapidly and the algae are not eaten will die eventually. The dead algae sink to the bottom and there is an accumulation of dead organic matter. Besides, this material is the food base for example worms and mussels, it is also food for bacteria. These organisms require oxygen to break down the material and can create large scale oxygen depletion. Because algae different needs, there is clear shift in the flourishing of the different species throughout the year. It is especially at this growth to problems with oxygen depletion in lakes, among other things occur. The largest blooms of algae occurs over the spring (NERI, undated).
5 Cultivation of algae and conditions for optimum growth.
When a plant for the production of algae to form, there is a lot of factors come into play. You will, from the producer, have such high returns as quickly as possible, so it obviously makes a lot of demands on their physical characteristics, and requirements for the medium as the algae are in. As described in a previous chapter, algae, both as all other photosynthetic organisms, growth and reproduction of a certain number of factors including the available amount of (sun) light, water and nutrients and the total number of algae in the medium (as a growth inhibitor). In this section we will describe how the cultivation of algae is and answer the following questions: What conditions for optimum growth (light, water, food)? How does this works out, and these may directly converted to algal production of biofuel as eye? Are there any geographical optimum locations?
Across the globe, there are algae, ranging from the most extreme temperature locations, for the most salts and to the places with the highest pH fluctuations. Algae can live in a great variety of environments. However, there is great variation in how "good" they live in relation to how much reproduction and biomass increase can be observed. We start by looking at how the lighting conditions should be. It is concluded that in order to keep costs down, the light source must be sunlight. If we then look at the composition of an optimal growth media must have, must be based on the given Alges own composition. But generally for all micro algae's needed nitrogen (N), phosphorus (P), iron compounds and in some cases, silicon (Si). However, it should be added that especially phosphoric be supplied in large quantities of surplus, as something of the amount will form compounds with iron, and therefore no longer be available to the algae (Chisti, 2007). Another substance that is essential for algae growth are carbon (C). Microalgae dry weight consists of approx. 50% carbon (Sanchez Miron et al., 1999). And most of this carbon get algae from CO2 relations. So if you have to produce for example 1 ton of algae biomass will be standard around. 1.8 tonnes of CO2, see below:
1 tonne of algae biomass ≈ 0.5 t C = 500 kg C = 500,000 g. C.
500,000 g. C ∙ 12.0107 g/mol-1 =
41629.55 C mol
1C + 2O → CO 2:
41,629.55 mol ∙ 2 O = 83,259 mol O:
83259mol O ∙ 15.9994 g / mol =
1332095 g O = 1.332 t O:
1332 tonne O + 0.5 ton C = 1.832 tonnes of CO2
There must be fed large amounts of CO2 to the plant during the day (in sunlight), however, that input is kept under surveillance when they did not want to form carbonic acid, as this would "use" a portion of the amount of carbon, and acidify growth environment with the risk of beating to death the algae.
One way to obtain these quantities of CO2 is by placing the plant at an existing power, possibly burning fossil fuels. We could connect algal plant to power plant stack and thus get cheap if not free of CO2. Experiments with this method has yielded promising results (Yun et al., 1997).
We will in the following sections examine the two methods currently exist for large scale production of algae. Namely "Raceway Ponds" and "tubular fotobioreaktor".
5.1 Raceway Ponds
We could not find a Danish term for the raceway ponds, so we will use the English expression through this section and later.
Raceway Ponds is a partially closed system where water circulates around in a large orbit (see Fig. 5.1). The course is approximately 0.3 meters deep and can be built in concrete or stamped soil, possibly lined with white plastic on the bottom. A place on the track is located three elements. A motorized water wheel ensures circulation of the system to avoid generating sediment and to the input of nutrients comes around. In addition, there is a drain cock, where algal mass can be collected and a tap input that adds nutrients to the environment. This kind of system of cultivation is widely used and there are plants covering 440,000 m2 (Spolaore et al., 2006). They are used today primarily for the cultivation of algae for food. A major benefit of this system is the relatively cheap price for the behavior of the plant compared with the second type of system. However, there are also numerous drawbacks associated with this type of plant: cooling water takes place only through evaporation. There is thus a significant loss of water for this, and there can be wide fluctuations in temperature during the day, and during seasons. Another major problem is the open structure. It is often seen in raceway ponds that the water becomes contaminated with undesirable algae strains and other organisms living on the algae (zooplakton in particular). So although there is an advantage of the low price behavior, there are numerous obstacles that we deem prefer more down.
Fig. 5.1 shows a schematic overview of a raceway pond. (Chisti, 2007)
5.2 tubular fotobioreaktor
Otherwise raceway ponds are tubular fotobioreaktorer a completely closed system (see fig. 5.2 on next page). It has been this way (almost) completely exclude the risk of contamination of the algal medium. The system is composed of a long series of clear tubes of either plastic or glass. It is in these tubes, the algae that captures light and have a diameter of not more than 10 cm. This limitation is due to the wider the pipe, the greater will be overshadowed for the light to the algae, which are located in the center. The fluid in these tubes circulates as in the first round system. Again, there is a tap for tapping seaweed soup with, but there is also a second unit attached. Here comes the algal soup through and replenished with CO2 and other nutrients that may be cooled and is then pumped back into the pipes.
To achieve the greatest growth in this system, it is important that the pipes are oriented toward the sun. They should not shadow each other, and the most common is that they are put down along the ground, and with a white background (to create reflection, albedo). One can make systems that do not depend on sunlight but by electric light, but these systems are too expensive for commercial large scale production (Pulz, 2001).
Sedimentation of algae avoided as in raceway ponds by stirring with either a mechanical mill or an air pump.
There are at least two problems with the closed system. 1: There will be related to photosynthesis generated a lot of oxygen (up to 10 g O2 m-3 ∙ ∙ min-1) and when you up to these levels of dissolved oxygen in water, it can directly inhibit photosynthesis and with intense sunlight fotooxidative cause damage to the algae (Molina Grima et al., 2001). This means that there must afiltes at various stations where the overskydne can bubble of oxygen. This means that there is a natural limitation on the length of the tubes. The reason that there must be specific "stations" to afiltningen, is that we want to avoid direct contact with air to algal broth to prevent the previously mentioned pollution. 2: There is a need for cooling system. This can be done relatively simply and cheaply in the heat transfer tubes with water (heat-exchange system), or by evaporation of water sprayed on the outside of the pipes.
Fig. 5.2 shows a schematic overview of a fotobioreaktor (Chisti, 2007).
5.3 Comparison of the two systems
Table 5.3 compares the two methods for the production of algae, where we look at production of 100,000 kg. Biomass per. year.
Raceway Ponds (R)
Fotobioreaktor (R)
Annual biomass production (kg)
100,000 (R)
100,000 (F)
Volumenmetrisk production (kg m-3 day-1)
0.117 (R)
1.535 (F)
Land productivity (kg m-2 day-1)
0.035 (R)
0.072 (F)
Biomass concentrations in algal solution (kg m-3)
0.14 (R)
4.00 (F)
Table 5.3 after Chisti, 2007
The results obtained from real experiments in large-scale production. As shown in the table (Table 5.3), all the results from the different variables in fotobioreaktorens favor. The volumenmetriske production is more than 13 times greater for fotobioreaktoren (see box 5.3). Because of these favorable conditions the yield is much higher per. unit area for just this technology. In order to transform algae soup to biobrænstof it is important to have the algae cleaned off. This can be done by mechanical filtration or centrifugation, but is relatively costly. But it is significantly cheaper for algal broth derived from fotobio reactors when biomass concentration is almost 30 times greater than for algal soup in raceway ponds
5.4 Locations
We have mentioned earlier that light is an important factor in optimal cultivation of algae. So it would be logical to conclude that the more light the algae receive the better. Apart from this assumption would be equatorial own ideal locations for growing plants. It is not quite so together. Lysmætning and fotoinhibition are two factors that come into play. Lysmætning is the point where light intensity is at a level so that the biomass growth rate is highest. For example, the diatom alga Phaeodactylum tricornutum's lysmætningspunkt at 185 μE m-2 s-1 (Mann & Myers, 1968). The average light intensity at the equatorial regions at dinner is about. 2000 μE m-2 s-1, and is thus significantly higher than algens lysoptimum. So one could imagine that more than needed light did or intended for, but again shows this not to be true. Fotoinhibition is an expression of too much light can be harmful to the photosynthetic organism growth rate.
One can not say anything about where on earth a plant would work best when there are so many factors that come into play. With regard to the amount of light we have seen that it is not necessarily the best, where it is strongest. It therefore depends on the specific algae, they choose to work with, how much light, heat and food, required for optimal growth.
6 From soup algae for biofuel
When you must transform a given biomass to a product that you can use for something useful, there are many things to take into account. This obviously also applies when it comes to producing biofuels for transport from the algal mass. Here it is especially important, how much energy you get out compared to how much energy it takes to produce the fuel. In addition, the product must consist of a series of specific substances, so that the fuel is suitable for engines, it must operate, so it does not harm the environment, not too toxic and so it does not fill or weigh too much. The last criterion means that it must have some energy stored per. volume or weight.
There is a long series of processes to convert algae to different types of biofuel. Some of them require that you first drain the algae for liquid, which can be costly. For example, you can by centrifugation separating the water from. This method, however, as mentioned earlier, for animals to be used in practice. Why they try to find other, cheaper ways to do it. Here are the different types of chemical flocculation or flocculation in the use of transgenic algae when the algae clump together so that they could easily be sorted by. You could also sort them by using apoptosis, ie a pre-programmed cell death, using transgenic algae (Gressel, 2008).
Other methods have the advantage that water can not be removed from the algal mass. This applies, for example, it is in English called liqefaction which, as its name implies, goes beyond that to transform algae into a liquid.
It has made a series of experiments with thermochemical liquefaction, which has been transformed algae at high pressure and temperature with and without catalyst. The transformation was as follows:
First filled the algae and the desired amount of catalyst that here was 0-5 mass% sodium carbonate (Na2CO3) in an autoclave in which the remaining air space was filled with nitrogen to atmospheric air out of the system. The pressure in the autoclave was increased to 3 MPa (~ 30atm) to avoid the water evaporated, thus should have spent more energy for heating. Autoclave then warmed up with an electrically heated to a temperature of 300-340 ° C, which was held at the time it wanted to keep the algal mass and oil in it. In the mentioned experiments, it was 30-60 minutes. Man on then cooled down to room temperature and the pressure lowered to atmospheric pressure, while the evolved gas was transferred to a bag. Then opened Mon autoclave and took out the contents. One saw the oil is separated from by dissolving it in triklormethan (chloroform) was evaporated at 40 ° C. The water phase and sediment were also disassembled for further investigation.
The experiments showed that one out of the set of circumstances that were used, have the best oil and as much energy out, by keeping the algal mass and oil in the autoclave for 30 minutes at a temperature of 340 ° C and 5 mass% added sodium (YF Yang et al., 2004).
7 By-products
Research into the process of converting algae into biofuel is still a new area. This means that there are some bids for various methods of production and transformation. There is therefore also a variety of products, both harmful and useful depending on the method used.
By-products from the conversion of algae to biofuel include in most cases, the greenhouse gases methane, hydrogen and carbon dioxide. These are some fairly bad products on the environment which we immediately want to avoid. Hydrogen and methane can be used wisely. Hydrogen can for example be used for fuel, thus creating yet another source of energy. Methane can also be used as energy in transport. With respect to carbon dioxide, the situation is not so critical. During the growing concern algae large quantities of carbon dioxide. This actually causes a neutrality with respect to the content of carbon dioxide in the atmosphere (Yang YF et al., 2004).
Algaelink, a company in Holland, which produces biodiesel from algae, using a relatively new approach to transforming algae. This method requires no chemicals, and the remaining by-products is therefore quite natural and useful to, for example, dietary supplements manufacturers or pharmaceutical companies (Friend, 2008). By-products include beta-carotene and astaxanthin. Beta-carotene is a precursor to vitamin A, and you know it from carrots. The body stores the beta-carotene in the liver, and here it is converted as needed to vitamin A. It is an important antioxidant for the body, among other things reduces the risk of cancer, protects against infections and strengthens the skin and mucous membranes in the intestines, trachea and urinary tract (Bionordic, 2000). Astaxanthin is also a natural antioxidant and is found in addition to algae also in seafood such as salmon, trout and shrimp. It is also found in few birds such as flamingos. It acts as a red pigment, which is also seen in, for example shrimp, but by binding to different proteins may also appear as green, yellow, blue or brown. Astaxanthin is important for the body's immune response. It counteracts including arthritis, cardiovascular disease and sunburn. It is currently at an experimental stage in the medical industry, and has proven positive effect on both stress and Alzheimer's and Parkinson's disease, partly because the substance can cross the blood-brain barrier. In nature, fish holds, such as salmon feed with astaxanthin, and get the natural reddish color. In salmon farming has no access to vitamins and are instead fed dyes to be marketed just as good as the wild salmon. Man has not even able to form astaxanthin and is therefore dependent on astaxanthinholdige foods or supplements. These foods include fish and shellfish. Attempts are therefore also with the addition of astaxanthin in feed for fish and shellfish in farming as a way to make conditions as natural as possible (Alga Technologies, 2004).
Another product that can be used in the pharmaceutical field is sterols (Friend, 2008), which together with tri-glycerides and phospholipids is one of the three groups of different fats. The most famous waxy fat group inside sterols are cholesterol, mainly found in meat, milk, eggs and butter. Also include sterols also certain hormones and precursors of vitamin D (Scmedes, 2000).
Besides the above products may be of some transformation methods also occur products (dry units) that can be used in feeds for animals.
8 Profitability
8.1 Economic
In order to make biofuel from algae for a real alternative, it is important that the price is the same as or cheaper than petroleum-based transportation fuels. We will in this section examine the costs of production and compare with the current price of gasoline, since this is the most widely used transportation fuel. For example, spending in the U.S. in 2003 476 giga liters (International Energy Agency, 2006). With the prices are on gasoline today costs one GJ of gasoline (95 octane) 306 pounds. If we compare this with an estimated cost of a GJ from Fischer Tropsch [1] Biofuel at 52-67 dkr. GJ, looks to biofuels is extremely competitive pursuit of fossil fuels
[1] Fischer Tropsch technology is a chemical process in which biomass, coal or gas converted to liquid fuel (Fischer & Tropsch, 1930). This fuel can be used to power cars and planes and more.
8.2 Environmentally
We have now seen that it is financially viable, but what about the environmental perspectives? One of the major problems with the combustion of fossil fuels is the major CO2 emissions and the environmental consequences that entails. This problem turns out not to exist with regard to the burning of biofuel. This technology is CO2 neutral, meaning that the amount of CO2 emitted during combustion is the same amount that was fixed from the atmosphere or incinerated by the cultivation of algae (Chisti, 2007)
9 Quality of biofuel from algae
As mentioned earlier, it is important that the fuel, you stand to eventually have a number of properties as a result of the chemical composition that matches the engines must operate, that it contains enough energy per. volume and unit mass and that it is not too toxic or polluting in any way. Therefore, one must also consider that these criteria are met. In the aforementioned experiments on thermochemical liquefaction looked at what the oil contained.
One sees that algae oil has a relatively high content of C17, C18 alkanes, n-naphtalin and some other substances. These are typical components of what we call heavy oil, which means that thermochemical liquefied oil from algae can be classified as heavy oil. (YF Yang et al. 2004)
Heavy oil is actually an oil of poor quality because it requires a further transformation of it, if you must end with a more usable oil (Barman, 2005). In addition, the combustion of heavy oil a number of products that are harmful to the environment (Batel, 2003). However, it should be noted that heavy oil is an important energy resource (Ke-Jian, 1997) and to upgrade to high-value products is of increasing interest commercially and financially (Barman, 2005).
All in all thermochemical liquefaction thus not directly a sustainable method for the conversion of algae. If you can find a method for upgrading heavy oil quality oil that is environmentally friendly and economically viable, liquefaction will be a sustainable method but it looks now, it is not.
As mentioned before, there are a number of other conversion methods. Most of these require that you drain the algae for liquid and therefore more costly, but it is possible that some of these can be used to produce biofuel quality.
10 The potential for biofuel from algae
In this section we will examine the quantity of biofuel from algae, which needed to replace conventional fuel. It has not been possible to find information on fuel quantities from around the world (as this figure is probably not very well known), but data from the U.S. seems partly to be representative. However, one could imagine that the average American consumes more gasoline (primarily) than an average European, because of cultural differences, lower gasoline prices and much more. Should it replace the total amount of fuel to the U.S. market, would, as mentioned earlier, would use approx. 0.5 billion m3 per year. Biofuels from conventional crops is not a realistic option. It can be seen in Table 10 below.
Table 10 shows the different crops to replace 50% of current U.S. consumption of fuels for transport (Chisti, 2007).
As seen from the fourth column shows the percentage of total U.S. agricultural land to be used for the crop (column 1) could replace 50% of current needs, it is really only biofuel from algae (in this case biodiesel) that is sufficient. Looking at the example of oil palm, which has proven to be a højudbytteplante with regard to oil content was 25% of current U.S. agricultural land planted with this crop to replace 50%. Looking contrast to microalgae, are levels of between 1-3% of current land (variation due to different percentage of oil in algae), which is said to be realistic. The results derived from large-scale trials in fotobioreaktorer, as mentioned earlier in the report. The reason for this large difference in the algae and all other crops is greatly accelerated algae growth. Most algae have doubled their biomass within 24 hours, and oil content of certain algae can be as high as 80%-mass. However, not all of these oils can be converted, but many are convertible into biodiesel production (Chisti, 2007).
11 Discussion
Our sources have been primarily scientific journals, but also websites from various organizations and companies and a single patent. We have not considered that there would be no weaknesses in our sources, such as bias. The only place where you could come into doubt the credibility to be with Shell and AlgaeLink (as these are private companies that want to be environmentally friendly companies, and may therefore represent a glossy image of their own technology), but these sources we used only with special care. Since the area we are in our project has been studied, is still relatively new, the project's methodology has the weakness that it is difficult to find evidence pointing in the same direction. We could usefully have had an expert in the field as a contact.
Our first definition was that we would only focus on biofuel from algae. This has meant that the scale of the project was cut down significantly and orderly made the whole project area. Our second definition was that we would focus on energy for transport, and biofuels from algae is already oriented transport, this was a natural boundary for our project, and it therefore had no greater significance.
12 Conclusion
The aim of the project and the related report was to explore the possibilities of biofuels derived from algae could replace traditional transport fuels. Algae are much better than land crops for biomass increase and the only real alternative, and the best way to grow algae on a large scale in the system, called tubular bioreactor. For optimal growth, a number of nutrients fed algae growth media. There is no general optimum location for a facility, as it largely depends on the algae they choose to work with. The technology to transform algae into biofuel exist, but there may be questions to whether the product is of high enough quality. This also depends on which method you choose to transform algae, since there are several. With regard to products of production, we can conclude that the formation of beneficial substances that could be used in various sectors. Among these are betakarotin and astaxanthin are important substances in particular the immune system.
Calculations indicate that fuel from algae in economic terms can easily compete with conventional fuels. In our example, a comparison of an estimated cost of biofuel and petrol prices, that biofuels were 5-6 times cheaper.
13 Perspectives
One might conclude from our study the remaining methods for the transformation and see whether the product would have the desired quality. For now, we are for some way from being able to use the end product directly in the car. You could even check on heavy oil in an environmentally friendly way, be transformed into oil of high quality.
Problemerne ved vores forbrug af fossile brændstoffer er mange. Fortsætter vi i denne retning, vil konsekvenserne være omfattende, fastslår flere eksperter. Man er derfor nødt til at finde på nye alternativer. For at disse nye alternativer kan få vind i sejlene, kræver det folkelig såvel som politisk opbakning. Danmark skal være vært for en stor klimakonference i 2009, hvor der skal findes en afløser til Kyotoaftalen og man kunne håbe på seriøs støtte til nye tiltag, der kan forbedre klimasituationen herunder forskning og udvikling i biobrændstof fra alger.
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