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ALGAE BIOMASS IN SPAIN: A CASE STUDY

"3rd European Maritime Day Stakeholder Conference", Renewable Energy and the Sea - Technological Innovation 18-21 May 2010. Gijòn, Spain. ALGAE BIOMASS IN SPAIN: A CASE STUDY. Emilio Molina Grima Dpt. Chemical Engineering, University of Almería, SPAIN emolina@ual.es. Outline.

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ALGAE BIOMASS IN SPAIN: A CASE STUDY

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  1. "3rd European Maritime Day Stakeholder Conference", Renewable Energy and the Sea - Technological Innovation 18-21 May 2010. Gijòn, Spain ALGAE BIOMASS IN SPAIN: A CASE STUDY Emilio Molina Grima Dpt. Chemical Engineering, University of Almería, SPAIN emolina@ual.es

  2. Outline • Feasibility of microalgae biofuel • Current scenario • Case study: cost analysis • Improving the energy prospect of algae • Challenges in decreasing cost • Recommendations

  3. Feasibility of algal biodiesel (Y. Chisty, 2007. Biotechnol. Adv.) United States biodiesel needs = 0.53 billion m3 (to replace all transport fuel) Not feasible a Optimistic values b Proved values Proved Estimated a, 20% w/w oil in biomass b, 40% w/w oil in biomass c, Phaeodactylum tricornutum 20% oil in biomass, 5glipids/m2·day. Acién Fernández et al., (1998) d, Scenedesmus almeriensis, 16% oil in biomass. Fernández Sevilla et al., (2008) e, Nannochloropsis sp. Two-step process 200 mgoil/L·day, 9.5 gbiomass/m2·day, Rodolfi et al., (2009) f, Nannochloropsis sp. Two-step process tropical area, Rodolfi et al (2009) 1) Feasibility of microalgae biofuel

  4. Small scale facilities Description of the system Sea water 220 L airlift tubular photobioreactor Phaeodactylum tricornutum 18,750 L oil /ha·year Sea water 110 L flat panel photobioreactor Nannochlropsis sp. 23.500 L oil /ha·year (Acién Fernández et al., 1998, Biotechnol. Bioeng.) (Rodolfi et al., 2009, Biotechnol. Bioeng.) 1) Feasibility of microalgae biofuel

  5. Large scale facilities Description of the system Freshwater 4,000 L tubular photobioreactor Scenedesmus almeriensis 17,330 L oil/ha·year 1) Feasibility of microalgae biofuel

  6. What is the current scenario? Overall energy data Biomass annual productivity, B≈ 100 tons ha1 Biomass energy content, Ebiomass ≈ 17,000 MJ ton1 Experimental data Energy in algal oil, Eoil≈ 38,000 MJ ton1 Energy in residue, Eresidue≈ 11,750 MJ ton1 Energy balance Radiation PAR (30,511 GJ ha1) Total energy in algal oil Total energy in oil-free biomass Total energy in biomass Phot.Efficiency 2.78% Global 5.56% PAR 2) Current scenario

  7. Solar efficiency Efficiency in the conversion of sunlight into organic matter ENERGY LOSSES ENERGY REMAINING 100% impinging total radiation infrared radiation (50%) 50% photosynthetic active radiation reflexion, transmission, unspecific absorption (30%) 35% absorbed by pigments conversion into photochemically active radiation (25%) 26% active in photochemistry conversion into chemical energy (70%) 8% energy in synthesized carbohydrates photoinhibition, respiration, photorespiration (40%) 5% net stored energy 2) Current scenario

  8. Maximum achievable Maximum energy conversion achievable CHALLENGE ENERGY COST 2) Current scenario

  9. Case study: Tubular photobioreactor Photobioreactor engineering features Volume = 10 units x 3.0 m3 = 30 m3 Height 2.2 m, lenght 20 m Separation between reactors: 1.4 m Surface occupation =20 m2(40) per PBR Volume to surface ratio = 70 L/m2 3) Case study

  10. Case study: Tubular photobioreactor Overall process Culture medium Photobioreactors Centrifugation Lyophylization Control unit Dry biomass 3) Case study

  11. Case study: Tubular photobioreactor Production cost 3) Case study

  12. Case study: Tubular photobioreactor Production cost 3) Case study

  13. Case study: Tubular photobioreactor Economic analysis MAJOR EQUIPMENTS 3) Case study

  14. What is the challenge? Major factors to be solved ENERGY COST 4) Improving the energy prospect of algae

  15. Energy balance Solar radiation and power consumption • Energy source = Sun (250 W/m2) • Considering maximum solar efficiency 5%: • Power consumption<100 W/m3 • V/S<100 L/m2 • Biomass productivity>0.5 g/Lday Closed photobioreactors Open photobioreactors Open photobioreactors Closed photobioreactors 4) Improving the energy prospect of algae

  16. Cost analysis Specific challenges in decreasing the biomass production costs 5) Challenges in decreasing cost

  17. Cost analysis Specific challenges in decreasing the biomass production costs Optimal design Maximum scale Reduction building cost Photobioreactor cost<1 €/L Use of flue gases Improved CO2 supply systems CO2 cost<0.05 €/kg 5) Challenges in decreasing cost

  18. Cost analysis Specific challenges in decreasing the biomass production costs Large facilities Maximum automatization Continuous operation Supervision and maintenance Labor < 1.0 man/hectare Greenhouses Waste water Use of waste water Water recycling systems Culture medium cost<0.1 €/m3 5) Challenges in decreasing cost

  19. Assume that high photosynthetic efficiency values achieved under controlled laboratory conditions will remain unchanged outdoors Derive productivity estimation from theoretical values or from figures obtained with small-scale reactors and/or short time intervals Invoke biomass productivity values per surface unit exceeding the efficiency limits of photosynthesis Calculate (and claim) high areal productivity values on the basis of the footprint of a reactor unit, instead of considering the surface really occupied by the unit in the reactor field Ignore the difficulties of keeping a monoalgal culture outdoors (forgetting about predators and contaminants) Ignore that the technology for mass production of microalgae is new and relatively complex - PLEASE, DO NOT RAISE FALSE EXPECTATIONS - PLEASE, DO NOT TRUST COMPANIES WITH FINANCE AND COMMUNICATION EXPERTS, BUT NO (REAL) SCIENTISTS What should be avoided? 6) Recommendations

  20. Find or develop the top microalgae, with high productivity outdoors, harvestability, resistence to contamination, tolerance to high oxygen levels and extreme temperature and elevated yields of either carbohydrates or lipids, suitable as feedstock for ethanol or biodiesel, respectively Develop appropriate reactors, with low manufacture and operation costs Verify productivity values at reasonable scale (demonstration plant) and throughout a complete annual cycle (at least) Ensure adequacy of the energy balance for the process. How much fossil energy is required in relation to that contained in the generated biofuel? Design an integral management of nutrients (CO2 from flue gases as source of C, recycling of culture medium, waste water, etc.) What should be done? R&D 6) Recommendations

  21. Design an integral use of the generated biomass, that envisage full utilization of the material left upon extraction of the feedstock Since marine microalgae oil content is superior to freshwater microalgae, and the lipid hydrogenation technology is a cheap, easy and fully developed technology, we should study the feasibility and scalability of growing algae offshore. Test the feasibility of heterotrophic growth (dark fermentation) of microalgae as a near-term route of biodiesel production What should be done? R&D IN THIS WAY, PROMISING TECHNOLOGIES FOR BIOFUEL FROM MICROALGAE MAY BE DEVELOPED OTHERWISE, CREDIT CAN BE LOST WHEN UNPROVEN (FALSE) EXPECTATIONS ARE NOT ACHIEVED 6) Recommendations

  22. ACKNOWLEDGEMENTS Inst. Bioq. Veg. Fotosíntesis CSIC, Sevilla, SPAIN Dpt. Chemical Engineering University of Almería, SPAIN

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