Journal of Applied Phycology

, Volume 21, Issue 5, pp 509–517 | Cite as

Biofuels, facts, fantasy, and feasibility

  • David Alan WalkerEmail author


It is frequently claimed that green algae are intrinsically more productive, often by orders of magnitude, than higher plants commonly grown as crops for food. There is no firm evidence for this belief. On the contrary, there is much experience which shows that algae are not more but less productive. Under optimal conditions, all green organisms photosynthesize at the same rate in low light and, whilst commonly cultivated ‘sun’ species show some differences in rate in full light, these do not translate into widely different rates of accumulation of biomass. Accordingly, irrespective of crop, one acre of land, pond or bioreactor, can annually yield about enough biomass to fuel one motor vehicle or meet the calorific requirement of several people. This amount of biomass is not sufficient to make other than a very small contribution to our present road transport requirements and yet contributes significantly to global food shortages and rising prices. Reliable evidence also suggests that, if all of the inputs are taken into account, the net energy gain of liquid biofuels, derived either from algae or terrestrial crops, is either very modest or non-existent and will therefore bring about little or no sparing of carbon dioxide emissions.


Algae Biofuels Energy balance Photosynthesis Productivity 



I am most grateful to John Benemann, Anton Haverkort, Ulrich Heber, and Avigad Vonshak, for advice and much needed criticism.


  1. Barber J, Archer MD (2004) ‘Photosynthesis and photoconversion. In: Series on Photoconversion of Solar Energy - Vol.2 Molecular to Global Photosynthesis. Archer MD. Barber J (eds). Imperial College, UK. pp 1-41.Google Scholar
  2. Baldry CW, Bucke C, Walker DA (1966) Temperature and photosynthesis. I Some effects of temperature on carbon dioxide fixation by isolated chloroplasts. Biochim Biophys Acta 126:207–213. doi: 10.1016/0926-6585(66)90056-2 PubMedCrossRefGoogle Scholar
  3. BBC News Channel (2009) Go-ahead for new Heathrow runway
  4. Belay A (1997) Mass culture of Spirulina outdoors – The Earthrise Experience. In: Vonshak A (ed) Spirulina platensis (Arthrospira): Physiology, Cell-biology and Biotechnology. Taylor & Francis, London UK, pp 131–158Google Scholar
  5. Benemann J (2007) An in-depth look at biofuels from algae. Accessed September 2008
  6. Benemann J (2008) Opportunities & challenges in algae biofuels production'
  7. Benemann J (2009) Microalgae biofuels: a brief introduction.
  8. Benemann JR, Oswald WJ (1996), Systems and economic analysis of microalgae ponds for conversion of CO2 to biomass. Final report. US DOE Accessed September 2008
  9. Bjorkman O, Demmig B (1987) Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. Planta 170:489–504. doi: 10.1007/BF00402983 CrossRefGoogle Scholar
  10. Boardman NK (1980) Energy from the biological conversion of solar energy. Philos Trans R Soc Lond A 295:477–489. doi: 10.1098/rsta.1980.0144 CrossRefGoogle Scholar
  11. Briggs M (2004) Widescale biodiesel production from algae Accessed September 2008
  12. British Potato Council (2007) Provisional estimate of GB potato supply for Accessed September 2008
  13. Bullard MJ (2004) 'Photoconversion and energy crops' Pages 453-519 In:Photoconversion of Solar Energy, Vol.2 Molecular to Global Photosynthesis. Archer MD, Barber J (eds). Imperial College, UK. p 189-220Google Scholar
  14. Dale. BE (2007)‘The Cost of Biofuels’ in Chemical & Engineering News ISSN 0009-2347
  15. Dyer G (2006) How Long Can the World Feed Itself? Accessed September 2008
  16. Edwards GE, Walker DA (1983) C3, C4, Mechanisms, and Cellular and Environmental Regulation of Photosynthesis. Blackwell, Oxford, pp 1–542Google Scholar
  17. Edwards GE, Walker DA, (2004) ‘Photosynthetic Carbon Assimilation’ In Series on Photoconversion of Solar Energy - Vol.2 Molecular to Global Photosynthesis (189-220) Editors MD Archer & J Barber. Imperial College, UKGoogle Scholar
  18. Delieu T, Walker DA (1981) Polarographic measurement of photosynthetic O2 evolution by leaf discs. New Phytol 89:165–175CrossRefGoogle Scholar
  19. Emerson R (1929) Photosynthesis as a function of light intensity and of temperature. J.Gen Physiol 12:623–639CrossRefGoogle Scholar
  20. GreenFuels Online (2007 ) Growth Rates of Emission-Fed Algae Show Viability of New Biomass Crop Growth Rates.pdf
  21. Gressel J (2008) Transgenics are imperative for biofuel crops. Plant Sci 174:246–263CrossRefGoogle Scholar
  22. Haverkort AJ (1990) Ecology of potato cropping systems in relation to latitude and altitude. Agric Syst 32:251–272CrossRefGoogle Scholar
  23. Hodge, N (2008) Investing in Algae Biofuel Accessed September 2008
  24. Huntley ME, Redalje D (2007) CO2 mitigation and renewable oil from photosynthetic microbes: a new appraisal. Mitig Adapt Strat Glob Change 12:573–608CrossRefGoogle Scholar
  25. Johnston M, Foley JA, Holloway T, Kucharik C, Monfreda,C (2009) Resetting global expectations from agricultural biofuels. Env Res Lett 4: doi: 10.1088/1748-9326/4/1/014004
  26. Kania S & Giacomelli, G, (2000) Solar radiation availability for plant growth in Arizona controlled environment agriculture. Accessed March-August 2008
  27. Labate CA, Adcock MD, Leegood RC (1990) Effects of temperature on the regulation of photosynthetic carbon assimilation in leaves of maize and barley. Planta 181:547–554CrossRefGoogle Scholar
  28. Larson ED (2000) In memory of Professor David Hall. Energy for Sustainable Development 4:5–6CrossRefGoogle Scholar
  29. Leach G (1975) Energy and food production. Food Policy 1:62–73CrossRefGoogle Scholar
  30. Long SP, Zhu X, Naidu SL, Ort DR (2006) Can improvement in photosynthesis increase crop yields? Plant cell environ 29:315–330PubMedCrossRefGoogle Scholar
  31. Longhurst A, Sathyendranath S, Platt T, Caverhill C (1995) An estimate of global primary production in the ocean from satellite radiometer data. J Plankton Res 17:1245–1271CrossRefGoogle Scholar
  32. National Farmers Union U.K. (2006) UK biofuels - land required to meet RTFO 2010. Accessed September 2008
  33. Nielsen ES (1957) The chlorophyll content and the light utilization in communities of plankton algae and terrestrial higher plants. Physiol Plant 10:1009–1021CrossRefGoogle Scholar
  34. Noctor G, Foyer CH (1999) Homeostasis of adenylate status during photosynthesis in a fluctuating environment J. Exp. Bot. 51:347–356CrossRefGoogle Scholar
  35. Ort D, Long SP (2003) Converting Solar Energy into Crop Production. In Plants, Genes, and Crop Biotechnology (240-269). Edited by Chrispeels MJ, Sadava DE. Jones and Bartlett Publisher InternationalGoogle Scholar
  36. Pimentel D, Pimentel,M (1990) Land, energy and water: the constraints governing ideal U.S. population size. Accessed March-August 2008
  37. Pimentel D, Patzek TW (2005) Ethanol production using corn, switchgrass, and wood; biodiesel production using soybean and sunflower. Nat Resour Res 14:65–76CrossRefGoogle Scholar
  38. Pimentel D, Patzek TW (2007) Ethanol production: Energy and economic issues related to U.S. and Brazilian Sugarcane Natural Resources Research, In: Biofuels, Solar and wind as renewable systems. Pimentel D. (ed) Springer, Berlin. P 357-371.Google Scholar
  39. Pirt SJ (1986) The thermodynamic efficiency (quantum demand) and dynamics of photosynthetic growth. New Phytol 102:3–37Google Scholar
  40. Potatoes (2007) This article may be downloaded from Accessed September 2008
  41. Pulz, O (2007) Growth Rates of Emission-Fed Algae Show Viability of New Biomass Crop. Growth Rates.pdf. Accessed May 2009
  42. Radmer R, Kok B (1977) Photosynthesis: limited yields, unlimited dreams. BioScience 27:599–605CrossRefGoogle Scholar
  43. Rao KK (1999) Obituary: David Hall, Professor of Biology, King’s College London. Photosynth Res 62:117–119CrossRefGoogle Scholar
  44. Robert Hill Institute at Sheffield,
  45. Rosenberg JN, Oyler GA, Wilkinson L, Betenbaugh MJ (2008) A green light for engineered algae: redirecting metabolism to fuel a biotechnology revolution. Curr Opin Biotechnol 19:1–7CrossRefGoogle Scholar
  46. Roy Soc Policy Document (2008 ) Sustainable biofuels: prospects and challenges.
  47. Sachs J , von (1887) ‘Periodic variations in growth’ In Lectures on the Physiology of Plants. Tr. by H. Marshall Ward. (532-569) Oxford, Clarendon PressGoogle Scholar
  48. Salassi, ME (2007) The Economic Feasibility of Ethanol Production from Sugar Crops. Louisiana Agriculture Magazine Winter Issue. Accessed September 2008
  49. Seaton GGR, Walker DA (1990) Chlorophyll fluorescence as a measure of photosynthetic carbon assimilation. Proc Roy.Soc.B 242:29–35CrossRefGoogle Scholar
  50. Sheehan, J., Dunahay, T., Benemann, J., Roessler, P. Weissman, J. (1998). Look Back at the U.S. Department of Energy's Aquatic Species Program: Biodiesel from Algae; Close-Out Report. 325 pp.; NREL Report No. TP-580-24190Google Scholar
  51. Spalding MH, Edwards GE, Ku MSB (1980) Quantum requirement for photosynthesis in Sedum praealtum during two phases of crassulacean acid metabolism. Plant Physiology 66:463–465PubMedCrossRefGoogle Scholar
  52. Squatriglia C (2008) Virgin Atlantic Biofuel Flight - Green Breakthrough or Greenwash?
  53. US Department of Agriculture (2005) Malaysia: Palm Oil Yields Surprisingly High: Accessed September 2008
  54. Vonshak A, Sivak MN, Walker DA (1989) Use of a solid support in the study of photosynthetic activity of Spirulina platensis. J Appl Phycol 1:131–136CrossRefGoogle Scholar
  55. Vonshak A, Chanawongse L, Bunnag B, Tanticharoen M (1996) Light acclimation and photoinhibition in three Spirulina platensis (Cyanobacteria) isolates. J Appl Phycol 8:35–40CrossRefGoogle Scholar
  56. Walker DA (1987) The use of the oxygen electrode and fluorescence probes in simple measurements of photosynthesis. pp 1-145 Oxygraphics Limited, Sheffield,U.K., Accessed September 5, 2008
  57. Walker DA (1989) Automated measurement of leaf photosynthetic O2 evolution as a function of photon flux density. Phil Trans R Soc Lond B 323:313–326CrossRefGoogle Scholar
  58. Walker DA (1992a) Energy, Plants and Man. , 2Oxygraphics, Brighton, p 277Google Scholar
  59. Walker DA (1992b) Excited leaves. Tansley Review 36. New Phytol 121:325–345CrossRefGoogle Scholar
  60. Walker DA (1995) Manipulating photosynthetic metabolism to improve crops: an inversion of ends and means. J.Exp.Bot 46 Special Issue 1253-1259Google Scholar
  61. Walker DA (1997) Tell me where all past years are. Photosynth Res 51:1–26CrossRefGoogle Scholar
  62. Walker DA (2000) Like clockwork. Oxygraphics, Sheffield, p 129Google Scholar
  63. Walker DA, (2008) ‘A New Leaf in Time’
  64. Walker DA, Osmond B (1986) Measurement of photosynthesis in vivo with a leaf disc electrode: correlations between light dependence of steady-state photosynthetic O2 evolution and chlorophyll a fluorescence transients. Proc R Soc B 227:267–280CrossRefGoogle Scholar
  65. Weissman JC, Goebel RP, Benemann JR (1988) Photobioreactor design: comparison of open ponds and tubular reactors. Bioeng Biotech 31:336–344CrossRefGoogle Scholar
  66. Wikipedia Oil Palms Accessed September 2008
  67. Wikipedia (2009) Net Energy Gain.
  68. Zhu X, Long SP, Ort DR (2008) Converting solar energy into crop production. Curr Opin Biotechnol 19:153–159PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.University of SheffieldSheffieldUK

Personalised recommendations