Algae- Hope or Hype? Photo Courtesy Ami Ben-Amotz John J Milledge Fossil Fuel Costs are Increasing BP statistical review of world energy June 2012 Demand for Fossil Fuel is Increasing BP statistical review of world energy June 2012 Reserves are Dwindling: ~50 years of Crude oil BP statistical review of world energy June 2012 There will be a continuing demand for
fluid fuels No Electric Planes Climate Change The overwhelming majority of scientists agree that this is due to rising concentrations of heattrapping greenhouse gases in the atmosphere caused by human activities The Met Office http://www.metoffice.gov.uk/climate-change Help! Biofuels to the Rescue? First generation biofuels, derived from food crops such as soya and sugarcane, are controversial due to their influence on world food markets .
As world food prices reach new highs, a handful of U.S. politicians and hard-hit corporations are readying a fresh effort to forestall the use of more U.S. corn and soybeans as motor fuel. Reuters Mon Feb 14, 2011 1:47pm GMT http://uk.reuters.com/article/2011/02/14/us-usa-ethanol-supportidUKTRE71D0UR20110214 Third Generation Biofuels Do not depend on agricultural or forestry ecosystems NREL National Renewable Energy Laboratory From 1978 to 1996, the U.S. Department of Energys Office of Fuels Development funded a program to develop renewable transportation fuels from algae. The total cost of the Program was $25.05 million The overall conclusion of these studies was that in principle
and practice large-scale microalgae production is not limited by design, engineering, or net energy considerations and could be economically competitive with other renewable energy sources NREL, 1998. A Look Back at the U.S. Department of Energys Aquatic Species ProgramBiodiesel from Algae. http://www.nrel.gov/docs/legosti/fy98/24190.pdf What are Algae? Algae are a diverse range of aquatic plants ranging from unicellular to multicellular forms and generally possess chlorophyll, but without true stems, roots and leaves Seaweed Pond Scum Algae can be divided by size into two groups
Macroalgae most commonly known as seaweed which can grow to considerable size. Microalgae as the name suggests are microscopic single cell organisms that exist individually, or in chains or groups. Their sizes range from a few micrometres (m) to a few hundreds of micrometres. Algae on the Tree of Life SCHLARB-RIDLEY, B. 2011. Algal Research in the UK. A Report for BBSRC. What are microalgae? Microalgae are a large and successful group of organisms, which flourish in the sea and fresh-water and naturally occurrence in virtually all water bodies. Microalgae are the most primitive form of plants with most contain green chlorophyll, and use photosynthesis to convert energy from the sun. Single cell organisms that exist individually, or in chains or groups. Their sizes range from a few micrometers (m) to a few hundreds of micrometers.
They are the base of the aquatic food chain. Microalgae are efficient plants Microalgae are the most primitive form of plants. While the mechanism of photosynthesis in microalgae is similar to that of higher plants, they are generally more efficient converters of solar energy because of their simple cellular structure. The cells grow in aqueous suspension and therefore have more efficient access to water, CO2, and other nutrients Are Microalgae Important ? Microalgae are responsible for over 50% of primary photosynthetic productivity on earth Producing 50% of the oxygen. Try breathing alternate hours! They budding sunlight factories for a wide range of potentially useful products, but as yet are barely used commercially They produced the oil that we are using today.
Oil doesn't come from dead dinosaurs In spite of some popular misconceptions, oil doesn't come from dead dinosaurs. Most scientists agree that oil was derived from dead bodies microalgae over the millennia Dunaliell a Salina Courtesy of Cognis
Australia Pty Ltd The typical algae bloom along the western coast of Ireland Observed on June 01 , 2008, by MERIS (Medium Resolution Imaging Spectrometer) on board of the European satellite ENVISAT. When phytoplankton population increases under favourite conditions the surface water gets coloured from brown to green and light-blue. Source the World Data Centre for Remote Sensing of the Atmosphere (WDC-RSAT)
Grow in wide range of light Land not suitable for traditional land plant cultivation could be used for algal cultivation Can growth in salt, brackish or waste water Low levels of water are causing considerable problems for farmers, with crop yields being hit BBC 10 June 2011 http://www.bbc.co.uk/news/uk-13722013 Microalgae grow in Salt water Microalgae grow in both salt and fresh water The culture of Salt water algae means
No competition for limited fresh water Use of lower grade land Use of marsh estuary areas (close to salt water) Large amounts of water are needed for microalgae biomass production Open systems Evaporative water loss NREL study 5.7 to 6.2 mm d-1 Closed systems Water for cooling Evaporation from open raceways growing microalgae can be the equivalent to 400 Kg of water for each kilogram of biomass produced Microalgae grow Oil Many microalgae that live in saline or freshwater environments), produce lipids as the primary
storage molecule. Microalgae have been found to have very high oil contents. In some case above 70% Examples lipid contents in algal species Nitzschia palea 80% Botryococcus braunii 75% Monallantus salina 72% Chlorella protothecoides 55% Scenedesmus dimorphus 40% Prymnesium parvum 38% Source University of Cape Town Algae can be Rich in Polyunsaturated Fatty Acids In higher plants, the number of double bonds in fatty acids only
rarely exceeds three, but in algae there can be up to six. Major Fatty Acid Composition of Algae Species Major fatty acids (% of total) 14:00 16:00 16:01 16:02 16:03 18:00 18:01 18:02 18:03 18:03 18:04 20:04 20:05 22:06 Bacillariophyceae Thalassiosira pseudonana 15 10 29 5 6
7 BIGOGNO, C., KHOZIN-GOLDBERG, I., BOUSSIBA, S., VONSHAK, A. & COHEN, Z. 2002. Lipid and Fatty Acid Composition of the Green Oleaginous Alga Parietochloris Incisa, the Richest Plant Source of Arachidonic Acid. Phytochemistry, 60,(5), 497-503. Modern Biotechnology Although, microalgae have been used for food by humans for thousands of years microalgae culture is one of the modern biotechnologies. Uni-algal culture was first achieved in 1890 with Chlorella Modern study of Algal Mass Cultivation is only about 70 years old Microalgae can produce many more times the amount of oil per year per unit area of land than oil seed crops. 93 tonnes ha-1 yr-1 But what is the true potential
yield? As early as the 1950s there were complaints of far fetched estimates of algal yields and very optimistic estimates of potential algal production have continued to appear. The maximum algal yield for potential sites such as SW USA (annual total solar insolation of 2000 KWh m-2 year-1) can be simply calculated from the calorific value of the algal based on its composition and the maximum theoretical photosynthetic efficiency. Maximum theoretical algal biomass is of the order of 400 tonnes ha-1 year-1 Maximum Calculated Algal Yields Algae oil Calorific value Yield Algae Yield Algae
90% 10.4 213 58 192 THEORETICAL MAXIMUM ALGAL OIL PRODUCTION Physical laws dictate the theoretical maximum, it represents a true upper limit to production that cannot be attained regardless of new technology advances. However, if algal biofuel production systems approach even a fraction of the calculated theoretical maximum, they will be extremely productive compared to current production capability of agriculture-based biofuels. THEORETICAL MAXIMUM ALGAL OIL PRODUCTION
Kristina M. Weyer, Daniel R. Bush, Al Darzins and Bryan D. Willson http://comste.gov.ph/images/files/TheoreticalMaximum_for%20ALGOIL%206-11-09.pdf Realistic Algal Yields Using a conservative photosynthetic efficiency of only 2.5% (less than a quarter of the theoretical maximum) in the SW USA could yield 25g m-2 day-1 or 91tons of algae per hectare per year. Seambiotic, in Israel, have recently calculated a similar figure for algae productivity in a similar light level region. Realistic Algal Yields NREL Single day productivities reported over the course of one year were as high as 50 grams of algae per square meter per day, and was the long-term target for the program, but consistent
long term yield again were probably closer to 25g m 2 day-1 . Ron Putt at the Department of Chemical Engineering Auburn University has also set growth for microalgae at economically practical rates in the region of 20 g m-2 day-1. Realistic Algal Yields A growth rate of 25g m day and -2 -1 an oil content of 20 % would produce 91 tonnes of algae per hectare per year and an oil yield of 18.2 tonnes hectare-1 year1 , over 48 times the yield for soy oil. Algal dry weight yields and photosynthetic efficiencies from
published sources. Reviews Yield Photosynthetic Suggested Achievable g m-2 d-1 Efficiency % Yield g m-2 d-1 5-21 1.2 -3 20-28 (Tamiya, 1957) 15-25
0.25 30 (Goldman, 1979a) 3-8 Reference (Reijnders, 2009) 20 (Brune et al., 2009) 10-40 (Singh and Olsen, 2011) Published Experimental Data Yield
gm d -2 -1 Photosynthetic Suggested Achievable Efficiency % Yield g m d -2 25 -29 16 Reference -1 (Johnson et al., 1988) 1.1 3.15
20 (Weissman et al., 1989) 15 (Laws and Berning, 1991) 16-35 ( Moheimani and Borowitzka, 2006 2.3 )(Bosma et al., 2007) 2.8 (Strik et al., 2008) Microalgae capture Carbon Dioxide CO2
Microalgae like plants use the suns energy in photosynthesis to convert CO2 and water into sugars and other organic compounds. Photosynthesis in microalgae is generally more efficient because of the simple cellular structure Microalgae are more tolerant of high CO2 concentrations Microalgae cells grow in aqueous suspension and therefore have more efficient access to water, CO2, and other nutrients Photosynthesis can be simplified into two reactants (carbon dioxide and water) and two products glucose and oxygen), represented by the chemical equation: 6CO2 + 6H2O = C6H12O6 + 6O2 It may be further simplified for the calculation of relative molecular weights CO2 + H2O ---> [CH2O] + O2 Relative Atomic Weight Hydrogen Carbon C Oxygen O Oxygen
Relative Molecular Weights H 1 Carbon Dioxide CO2 44 (12 + (16x2)) 12 Water H2O 18 ((1x2) + 16 ) 16 Formaldehyde CH2O 30 (12 + (1x2) + 16) O2 32 (2x16) For every ton of algae produced in it will capture just under one and a half tons of carbon dioxide (44/30) Algae Can Reduce NOx SOx and NOx in flue gases were found to have little negative effect on algae NREL, 1998 NOx can provide the Nitrogen Source for the algae NREL, 1998 NOx was reduced by 85% by using algae in a study by MIT Algae could capture over 60kg of NOx per ton of
dry algae produced How are microalgae grown? Closed Systems Photo-Bioreactors Open Systems Race-track ponds How are microalgae grown? Closed Systems Photo-Bioreactors Open Systems Race-track ponds High Capital Cost Relatively Complex
High degree of Control Low Risk of Contamination High Maintenance Low Capital Cost Relatively Simple Some Environmental Control Risk of Contamination Low Maintenance Biotechnology Farming Dunaliella, Murcia, Spain US$ 10 million loss Ami Ben-Amotz @ NASA November 20, 2008 GreenFuel Technologies Co Arizona, USA After a few weeks operation - heavy contamination, difficulty
to clean Ami Ben-Amotz @ NASA November 20, 2008 GreenFuel Technologies Co, Arizona, USA Bags trial, high cost scale up Ami Ben-Amotz @ NASA November 20, 2008 Almost all commercial algae production plants use open ponds Chlorella, Spirulina and Dunaliella Cyanotech Hawaii, USA Cognis, Hutt, Western Australia Racetrack Algal Pond NREL, 1998. A Look Back at the U.S. Department of Energys Aquatic Species ProgramBiodiesel from Algae. http://www.nrel.gov/docs/legosti/fy98/24190.pdf
Head losses & Mixing Energy 60% of the total of the energy in the algae could be used in mixing If algal production is 25g m-2 d-1 with a calorific value of 4.7Kcal g1 the paddlewheel will consume 60% of the total of the energy in the algae (area of raceway 103 m2, total algal yield 2.58 kg d-1, daily pond algal calorific value 14.1 kWh Head losses vary with square of mean velocity, but the pumping power varies with the cube of the mean velocity. The circulation energy in photo-bioreactors has been estimated to be 13 to 28 times that of open raceway ponds and this high operational energy of PBRs may preclude their
use for algal fuel production . 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 40624077. Power Plant Chimney to the Pilot Plant Algae Ponds Algae Farm with Power Plant CO2 Capture NREL, 1998. A Look Back at the U.S. Department of Energys Aquatic Species ProgramBiodiesel from Algae. http://www.nrel.gov/docs/legosti/fy98/24190.pdf Required Low Cost Algae Harvesting The economy of microalgae production depends on the technology employed for the harvesting and concentrating the algal suspension E.W. Becker, Microalgae: Biotechnology & Microbiology 1994 Algal Biofuel Process Energy Output
O 2 By-products CO2 Growth Water & Nutrients Dilute Algae Harvesting concentration Conc Algae Operational Energy Input Energy Extracti
on Nutrients Recycled The Challenges of Algae Harvesting Minute Concentration of Algae - around 0.02% dry solids. Small size most algae are below 30m. Density Algae are only slight more dense than water. High Negative Surface Charge algae remain dispersed in a stable suspension especially during growth phase in optimum conditions and spontaneous flocculation and sedimentation are negligible. Algae must be Constantly Harvested Unfortunately algae cannot be left and harvested
at the end of a long growing season. They must be constantly harvested. Hydraulic retention times 1 to 5 days. Potential Algal Harvesting Methods Sedimentation Flocculation Floatation Filtration Centrifugation
Increasing Operational Energy (Mohn, 1988, Molina Grima et al., 2003, Shen et al., 2009) Advantages Disadvantages Dry solids Output Concentration Centrifugation Can handle most algal types with High capital and operational costs. 10-22 % rapid efficient cell harvesting. Filtration Wide variety of filter and
Highly dependent on algal species, 2-27 % membrane types available. best suited to large algal cells. Clogging and fouling an issue. Ultrafiltration Can handle delicate cells. High capital and operational costs 1.5-4 % Sedimentation Low cost. Algal species specific, best suited 0.5-3 %
Potential for use as a first stage to dense non-motile cells. to reduce energy input and cost Separation can be slow. of subsequent stages. Low final concentration Chemical Wide range of flocculants Removal of flocculants and flocculation available, price varies, although chemical contamination
3-8 % can be low cost. Flotation Can be more rapid than Algal species specific. High capital sedimentation. Possibility to and operational cost. combine with gaseous transfer. >7% Disc-bowl Centrifuge an Ideal Solution? Courtesy GEA Westfalia Separator UK Ltd
A Westphalia HSB400 disc-bowl centrifuge with intermittent self cleaning bowl centrifugal clarifier has a maximum capacity of 95m3 hr-1, but is limited to 35m3 hr-1for algae harvesting. The maximum power of the motor is 75Kw, but is probably normally using around 50kw Elegant Engineering, but at high Energy Cost 0.02% DW algae Feed 0.02% x 35000 = 7kg of dry algal material 20% x 7 =1.4kg of algal oil 90% x 1.4 = 1.26kg biodiesel @ 10.35kwhr 13kwhrs of fuel calorific value from one hour of
centrifugation using 50kwhr 0.5% DW algae Feed 0.5% x 35000 = 175kg of dry algal material 20% x 175 = 35kg of algal oil 90% x 35 = 31.5kg biodiesel @ 10.35kwhr 326kwhr fuel calorific value, but still an energy input for energy produced of over 15% for the harvesting process. Could algal suspension be settled in a conical settlement tank, of the type used in the water treatment industry in activated sludge? Extraction Energy From Algae Direct Combustion Oil Extraction Trans-esterification to
Biodiesel (FAME) Anaerobic Digestion Pyrolysis Fermentation to Bioethanol Fuel Cells Methods of energy extraction from microalgal biomass Utilises entire Requires drying of Primary energy organic biomass biomass after product harvesting Direct Combustion
Yes Yes Heat Pyrolysis Yes Yes Primarily liquid by flash pyrolysis Gasification Yes Yes b (conventional) Primarily Gas
Liquefaction Yes No Primarily Liquid Bio-hydrogen Yes No Gas Fuel Cells Yes No
Electricity Bioethanol No No Liquid Biodiesel No Yes Anaerobic digestion Yes No a
a c Liquid Gas Currently restricted to fermentable sugars as no large-scale commercial production of fuel bioethanol from lignocellulosic materials b Supercritical water gasification (SCWG) an alternative gasification technology can convert high moisture biomass c No current commercial process for the wet trans-esterification of wet microalgal biomass Summary of Algal Lipid Production Cost Estimates
PIENKOS, P. T. 2009. Algal Biofuels: Ponds and Promises. 13th Annual Symposium on Industrial and Fermentation Microbiology. NREL. Algal Biodiesel is Currently Uneconomic At present the process of producing fuel from algae would appear to be uneconomic with over 50 algal biofuel companies and none as yet producing commercial-scale quantities at competitive prices. It has been suggested that the cost of production needs to be reduced by up to two orders of magnitude to become economic. Others estimate biodiesel from algae costs at least 10 to 30 times more than making traditional biofuels ~50% of the published LCAs on microalgal biodiesel have a net energy ratio less than 1. Positive economic/energy studies required High value co-products Biogas production by Anaerobic digestion
Use of technology unproven at commercial scale such wet biomass trans-esterification 65 Anaerobic Digestion of Algae could produce net Energy Settlement Centrifugation Harvesting Algal Harvesting Settlement Concentration Factor Settlement Algal Harvesting Centrifugation Concentration Factor Centrifugation Harvesting Equipment Settlement Harvesting Equipment Centrifugation % % kWh d-1 kWh d-1 60
Total Operational Energy Input Net Energy kWh d-1 129.17 139.42 23.19 4.84 28.03 29.23 6.22 35.45 788.70 798.95 23.19 4.84 28.03 29.23
6.22 35.45 198.14 179.70 149.74 181.95 199.70 258.78 276.52 918.31 936.05 307.06 325.50 355.46 407.45 558.11 330.63 481.28 -328.91 -178.25 Current examples of nonfuel uses of Microalgae -carotene produced from Dunaliella Lina Blue, a blue Phycobiliprotein food colourant, produced from Spirulina
Docosahexaenoic acid (DHA), a polyunsaturated omega-3 fatty acid, produced by heterotrophic culture Crypthecodinium cohnii Sulphated polysaccharides for cosmetic products from Porphyridium Food and feed additives for the commercial rearing of many aquatic animals are produced from a variety of microalgal species. 67 Microalgal Biorefining Co-production of a spectrum of high value bio-based products (food, feed, nutraceuticals, pharmaceutical and chemicals) and energy (fuels, power, heat) from biomass that could allow the exploitation of the entire microalgal biomass produced. 68 Biorefineries should
be sustainable The energy inputs required by a biorefinery should be met by bioenergy produced from the refinery. 69 Good & Bad News Gene GreenFuel scientist to Technologies create algae Closing biofuel with Down The Harvard-MIT algae Exxon Mobil company winds down after Exxon Mobil expects to spend more than $600 million, which includes
$300 million in internal costs and potentially more than $300 million to SGI. spending millions and experiencing delays, technical difficulties Exxon at Least 25 Years Away From Making Fuel From Algae Its pretty obvious that theres nothing in the natural world to make the levels (of biofuel) that are needed, Craig Venter, the first mapper of the human genome and creator of the first synthetic cell, October 2011 Creating motor fuels from algae may not
succeed for at least another 25 years because of technical hurdles Exxon Mobil Corp Chairman and Chief Executive Officer, Rex Tillerson, March 2013 Adelaide scientists on the cusp of a biofuel breakthrough on algal biofuel project in Whyalla Muradel chief technology officer Associate Professor David Lewis believes its revolutionary process will produce hundreds of millions of dollars worth of oil a year in South Australia within 20 years. ADELAIDENOW 8th April, 2013 In a survey of more than 380 algae industry contacts showed; 65 % of algae producers said they planned to expand capacity in 2012. Respondents were optimistic that algae biofuels
will be commercially available and competitive with fossil fuels by 2020. 90 % believing that it is at least somewhat likely, and nearly 70 % believing it is moderately to extremely likely AlgaeIndustryMagazine.com (2012) http://www.algaeindustrymagazine.com/abo-survey-shows-increased-production-price-competitiveness/? utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+AlgaeIndustryMagazine+ %28Algae+Industry+Magazine%29 The Debate Continues Were making new investments in the development of gasoline and diesel and jet fuel thats actually made from a plant-like substance algae President Barack Obama at the University of Miami Field House in Coral
Gables, Fla., Thursday, Feb. 23, 2012 Algae fuel is not likely to be competitive with other forms of fuel anytime in the foreseeable future. It is definitely not a solution to Americans urgent energy crisis Newton Leroy "Newt" Gingrich 2012 Republican Party presidential nomination. March 2012
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