Advertisement

Life cycle analysis of algae biodiesel

  • Kyle Sander
  • Ganti S. Murthy
LCA for Energy Systems

Abstract

Background, aim, and scope

Algae biomass has great promise as a sustainable alternative to conventional transportation fuels. In this study, a well-to-pump life cycle assessment (LCA) was performed to investigate the overall sustainability and net energy balance of an algal biodiesel process. The goal of this LCA was to provide baseline information for the algae biodiesel process.

Materials and methods

The functional unit was 1,000 MJ of energy from algal biodiesel using existing technology. Systematic boundary identification was performed using relative mass, energy, and economic value method using a 5% cutoff value. Primary data for this study were obtained from The USLCI database and the Greenhouse Gases, Regulated Emissions and Energy use in Transportation model. Carbohydrates in coproducts from algae biodiesel production were assumed to displace corn as a feedstock for ethanol production.

Results and discussion

For every 24 kg of algal biodiesel produced (1,000 MJ algae biodiesel), 34 kg coproducts are also produced. Total energy input without solar drying is 3,292 and 6,194 MJ for the process with filter press and centrifuge as the initial filtering step, respectively. Net CO2 emissions are −20.9 and 135.7 kg/functional unit for a process utilizing a filter press and centrifuge, respectively. In addition to the −13.96 kg of total air emissions per functional unit, 18.6 kg of waterborne wastes, 0.28 kg of solid waste, and 5.54 Bq are emitted. The largest energy input (89%) is in the natural gas drying of the algal cake. Although net energy for both filter press and centrifuge processes are −6,670 and −3,778 MJ/functional unit, respectively, CO2 emissions are positive for the centrifuge process while they are negative for the filter press process. Additionally, 20.4 m3 of wastewater per functional unit is lost from the growth ponds during the 4-day growth cycle due to evaporation.

Conclusions and recommendations

This LCA has quantified one major obstacle in algae technology: the need to efficiently process the algae into its usable components. Thermal dewatering of algae requires high amounts of fossil fuel derived energy (3,556 kJ/kg of water removed) and consequently presents an opportunity for significant reduction in energy use. The potential of green algae as a fuel source is not a new idea; however, this LCA and other sources clearly show a need for new technologies to make algae biofuels a sustainable, commercial reality.

Keywords

Algae biodiesel Life cycle analysis Coproduct allocation Ethanol GHG emissions 

Supplementary material

11367_2010_194_MOESM1_ESM.pdf (391 kb)
(PDF 390 kb)

References

  1. Akers SM, Conkle JL, Thomas SN, Rider KB (2006) Determination of the heat of combustion of biodiesel using bomb calorimetry. J Chem Edu 83(2):260–262CrossRefGoogle Scholar
  2. Aresta M, Dibenedetto A, Barberio G (2005) Utilization of macro-algae for enhanced CO2 fixation and biofuels production: development of a computing software for an LCA study. Fuel Proc Technol 86:1679–1693CrossRefGoogle Scholar
  3. Borowitzka M, Borowitzka L (eds) (1988) Micro-algal biotechnology. Cambridge University Press, CambridgeGoogle Scholar
  4. CDWR (2007) Evaporation pan data. Tech. Rep., California Department of Water Resources. http://www.sjd.water.ca.gov/landwateruse/evaporation/. Accessed Oct 2009
  5. Ceron MC, Campos I, Acien JSF, Molina E, Fernandez-Sevilla J (2008) Recovery of lutein from microalgae biomass: development of a process for Scenedesmus almeriensis biomass. J Agric Food Chem 56:11761–11766CrossRefGoogle Scholar
  6. Chisti Y (2007) Biodiesel from microalgae. Biotechnol Adv 25:294–306CrossRefGoogle Scholar
  7. Clarens A, Resurreccion E, White M, Colosi L (2010) Environmental life cycle comparison of algae to other bioenergy feedstocks. Environ Sci Technol 44:1813–1819CrossRefGoogle Scholar
  8. Dale B (2008) Biofuels: thinking clearly about the issues. J Agric Food Chem 56:3885–3891CrossRefGoogle Scholar
  9. EIA (2008) Annual energy review 2008. Tech. Rep. 0384, Energy Information Administration, U.S. Department of EnergyGoogle Scholar
  10. GREET (2008) The greenhouse gases, regulated emissions and energy use in transportation model. Tech. Rep., Argonne National Laboratory, U.S. Department of Energy. http://www.transportation.anl.gov/modeling_simulation/GREET/. Version 1.8. Accessed Dec 2008
  11. Grima EM, Belarbi E, Fernandez FA, Medina AR, Chisti Y (2003) Recovery of microalgal biomass and metabolites: process options and economics. Biotechnol Adv 20:491–515CrossRefGoogle Scholar
  12. Hills C, Nakamura H (1978) Food from sunlight; planetary survival for hungry people. University of the Trees Press, Boulder CreekGoogle Scholar
  13. Huo H, Wang M, Bloyd C, Putsche V (2008) Life-cycle assessment of energy and greenhouse gas effects of soybean-derived biodiesel and renewable fuels. Tech. Rep. ANL/ESD/08-2, Argonne National Laboratory, U.S. Department of EnergyGoogle Scholar
  14. Kadam K (2001) Microalgae production from power plant flue gas: environmental implications on a life cycle basis. Tech. Rep. NREL/TP-510-29417, National Renewable Energy LaboratoryGoogle Scholar
  15. Kenny J, Barber N, Hutson S, Linsey K, Lovelace J, Maupin M (2009) Estimated use of water in the united states in 2005. Tech. Rep. Circular 1344, U.S. Geological SurveyGoogle Scholar
  16. Kim S, Dale B (2002) Allocation procedure in ethanol production system from corn grain. Int J LCA 7:237–243CrossRefGoogle Scholar
  17. Kim S, Dale B (2003) Global potential bioethanol production from wasted crops and crop residues. Biomass Bioenergy 26:361–375CrossRefGoogle Scholar
  18. Lardon L, Helias A, Sialve B, Steyer J, Bernard O (2009) Life-cycle assessment of biodiesel production from microalgae. Environ Sci Technol 43:6475–6481CrossRefGoogle Scholar
  19. Lembi C, Waaland J (eds) (1989) Algae and human affairs. Cambridge University Press, Boulder CreekGoogle Scholar
  20. Mehta SK, Gaur JP (2005) Use of algae for removing heavy metal ions from waste water: progress and prospects. Crit Rev Biotechnol 25:113–152CrossRefGoogle Scholar
  21. Nielsen P, Wenzel H (2005) Environmental assessment of ethanol produced from corn starch and used as an alternative to conventional gasoline for car driving. Tech. Rep., The Institute for Product Development, Technical University of DenmarkGoogle Scholar
  22. Raynolds M, Fraser R, Checkel D (2000) The relative mass-energy-economic (RMEE) method for system boundary selection. Int J LCA 5:37–46CrossRefGoogle Scholar
  23. Richmond A (ed) (1986) Handbook of microalgal mass culture. CRC, Boca RatonGoogle Scholar
  24. Sander K, Murthy G (2009) Enzymatic degradation of microalgal cell walls. ASABE paper no: 096054. 2009 ASABE annual international meetingGoogle Scholar
  25. Shapouri H, Salassi M, Fairbanks J (2006) The economic feasibility of ethanol production from sugar in the United States. Tech. Rep., U.S. Department of AgricultureGoogle Scholar
  26. Sheehan J, Camobreco V, Duffield J, Graboski M, Shapouri H (1998a) Life cycle inventory of biodiesel and petroleum diesel for use in an urban bus. Tech. Rep. NREL/SR-580-24089, U.S. Department of Energy and U.S. Department of AgricultureGoogle Scholar
  27. Sheehan J, Dunahay T, Benemann J, Roessler P (1998b) A look back at the US Department of Energy’s aquatic species program-biodiesel from algae. National Renewable Energy Laboratory, Golden CO. Report: NREL/TP–580–24,190Google Scholar
  28. Shelef G, Soder C (eds) (1980) Algae biomass; production and use. Elsevier, AmsterdamGoogle Scholar
  29. USLCI (2008) The U.S. life-cycle inventory database. Tech. Rep., National Renewable Energy Laboratory. http://www.nrel.gov/lci/database/. Accessed Dec 2008
  30. Ververis C, Georghiou K, Danielidis D, Hatzinikolaou D, Santas P, Santas R, Corleti V (2007) Cellulose, hemicelluloses, lignin and ash content of some organic materials and their suitability for use as paper pulp supplements. Biores Technol 98:296–301CrossRefGoogle Scholar
  31. Wang M (2005) Updated energy and greenhouse gas emission results of fuel ethanol. In: The 15th int symp alcohol fuelsGoogle Scholar
  32. Wang M, Wu M, Huo H (2007) Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types. Environ Res Lett 2:1–13CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Oregon State UniversityCorvallisUSA

Personalised recommendations