Environmental impacts of conventional plastic and bio-based carrier bags

Part 1: Life cycle production
  • Hsien Hui Khoo
  • Reginald B. H. Tan
  • Kevin W. L. Chng
PACKAGING SYSTEMS

Abstract

Background, aim, and scope

The use of bio-based products as carrier bags, packaging materials, and many other applications has been increasingly replacing conventional polymer products. One of the main driving forces of bio-plastic applications is the perceived depletion and scarcity of fossil fuels, especially petroleum. However, despite being introduced as an environmentally friendly alternative to plastics made from crude oil, the environmental benefits of bio-plastics remain debatable. This article serves to investigate whether or not bio-based materials are environmentally friendlier options compared to plastics and attempts to explain the rationale of the results.

Materials and methods

The production and disposal of both conventional plastic and bio-plastic carrier bags are investigated using life cycle assessment or LCA. A typical bio-based bag (made from polyhydroxyalkanoate or PHA) from the U.S. was selected to be compared with a locally produced polyethylene plastic (PP) bag in Singapore. In the LCA system, the raw materials for making polyethylene came from crude oil imported from Middle East and natural gas piped from Natuna gas field. The refinery and PP bag production processes are based in Singapore. Bio-bag production was entirely in the U.S., and the finished product was shipped to Singapore. The impact assessment results were generated for global warming potential, acidification, and photochemical ozone formation. Next, normalized results were calculated according to the parameters of Singapore’s annual emission inventory.

Results

The total environmental impacts of bio-bags showed considerable differences under various energy scenarios. When the energy expenditures to make bio-bags are supplied by U.S. electricity mix, the production impacts are about 69% higher, compared to the impacts from PP bags. With coal-fired power supply, the production impacts from bio-bag production turned out to be about five times greater than those from conventional plastics. The life cycle production impacts of PP bags are comparable to bio-bags when the energy supplied to the bio-material production chain is supplied by natural gas. Bio-bags are 80% more environmentally friendly than plastic bags when clean and renewable energy (geothermal) is used throughout its life cycle production stages.

Discussions and conclusions

By the use of LCA with different energy scenarios, this article sheds some light on the extent of environmental benefits (or drawbacks) of replacing plastic carrier bags with PHA bags. It was concluded that the life cycle production of bio-bags can only be considered as environmentally friendly alternatives to conventional plastic bags if clean energy sources are supplied throughout its production processes. It was also highlighted that the results should not be viewed as a global representative since the case study scope was for Singapore alone. Additional work by others on different biodegradable and compostable bags vary in results. Some of the complexities of such work lie in what is included or excluded from the scope and the adoption of different environmental impact assessment methods. Nevertheless, the authors’ attempt to compare the two bags may serve as a basis for identifying the major environmental burdens of such materials’ life cycle production.

Recommendations and perspectives

Although bio-based products have been mostly regarded as a sustainable solution for replacing petroleum-based polymers, in most cases, the amounts of resources and energy required to produce them have not been taken into account. Before bio-based plastics can be recommended as a preferred option to plastics, a few challenges have to be overcome. The main issue lies in reducing the energy used in the life cycle production of the bio-material from crops. The environmental benefits and drawbacks of both materials should also be more clearly highlighted by expanding the system boundary to include end-of-life options; this is carried out in part 2 (Khoo and Tan, Int J Life Cycle Assess, in press, 2010).

Keywords

Bio-based bag (PHA) Energy use Environmental impacts Life cycle production Plastic carrier bags Singapore 

References

  1. Akiyama M, Tsuge T, Doi Y (2003) Environmental life cycle comparison of polyhydroxyalkanoates produced from renewable carbon resources by bacterial fermentation. Polym Degrad Stab 80:183–194CrossRefGoogle Scholar
  2. Bertani R (2002) Geothermal power generating plant CO2 emission survey. International Geothermal Association News No. 49Google Scholar
  3. BUWAL (1991) Eco-balance of packaging materials. Environment Report No. 132, Bern, SwitzerlandGoogle Scholar
  4. Chen SS, Hussein WM (2005) Development of life cycle assessment activities in Malaysia. Proceedings of the International Workshop on LCA: Capacity Building in APEC Economies, December 15–16, Bangkok, ThailandGoogle Scholar
  5. Comstock K, Farrell D, Godwin C, Xi Y (2004) From hydrocarbons to carbohydrates: food packaging of the future. Available at http://depts.washington.edu/poeweb/gradprograms/envmgt/2004symposium/GreenPackagingReport.pdf/. Accessed August 2008
  6. Gerngross TU (1999) Can biotechnology move us toward a sustainable society? Nat Biotechnol 17:541–544CrossRefGoogle Scholar
  7. Gross RA, Kalra B (2002) Biodegradable polymer for the environment. Science 297:803–807CrossRefGoogle Scholar
  8. Hatti-Kaul R, Törnvall U, Gustafsson L, Börjesson P (2007) Industrial biotechnology for the production of bio-based chemicals—a cradle-to-grave perspective. Trends Biotechnol 25:119–124CrossRefGoogle Scholar
  9. Hauschild MZ (2005) Assessing environmental impacts in a life cycle perspective. Environ Sci Technol 39:905–912CrossRefGoogle Scholar
  10. Hauschild M, Potting J (2003) Spatial differentiation in life cycle impact assessment—the EDIP2003 methodology. Institute for Product Development Technical University of DenmarkGoogle Scholar
  11. Hetch J (1997) The environmental effects of freight. Organisation for Economic Co-operation and Development (OECD), ParisGoogle Scholar
  12. International Energy Agency (IEA) (2007) Electricity information database 2007 and CO2 emissions from fuel combustion database 2006. International Energy Agency, Paris, Available at http://www.iea.org/. Accessed August 2008CrossRefGoogle Scholar
  13. James K, Grant T (2005) LCA for biodegradable plastic bags. Centre for Design, RMIT, Australia. Available at http://www.cfd.rmit.edu.au/programs/life_cycle_assessment/lca_of_degradable_plastic_bags. Accessed April 2009
  14. Jimenez-Gonzalez C, Overcash M (2000) Life cycle inventory of refinery products: review and comparison of commercially available databases. Environ Sci Technol 34:4789–4796CrossRefGoogle Scholar
  15. Khoo HH, Tan RBH (2010) Environmental impacts of conventional plastic and bio-based carrier bags—part 2: end-of-life options. Int J Life Cycle Assess (in press)Google Scholar
  16. Kim S, Dale BE (2005a) LCA study of biopolymers (PHA) derived from no-tilled corn. Int J Life Cycle Assess 10:200–210CrossRefGoogle Scholar
  17. Kim S, Dale BE (2005b) LCI information of the United States electricity system. Int J Life Cycle Assess 10:294–304CrossRefGoogle Scholar
  18. Landis AE, Miller SA, Theis TL (2007) Life cycle of the corn-soybean agroecosystem for bio-based production. Environ Sci Technol 41:1457–1464CrossRefGoogle Scholar
  19. Murphy R, Bartle I (2004) Biodegradable polymers and sustainability: insights from life cycle assessment. Imperial College, London, Available at http://www.oakdenehollins.co.uk/pdf/biodegradable_polymers.pdf. Accessed April 2009Google Scholar
  20. Narita N, Sagisaka M, Inaba A (2002) Life cycle inventory analysis of CO2 emissions manufacturing commodity plastics in Japan. Int J Life Cycle Assess 7:277–282CrossRefGoogle Scholar
  21. Ohara T, Akimoto H, Kurokawam J, Horii N, Yamaji K, Yan X, Hayasaka T (2007) An Asian emission inventory of anthropogenic emission sources for the period 1980–2020. Atmos Chem Phys 7:4419–4444CrossRefGoogle Scholar
  22. Reed M, Renner J (2004) Environmental compatibility of geothermal energy. In: Sterrett FS (ed) Alternative fuels and the environment. Lewis, Boca Raton, p 25Google Scholar
  23. Shapouri H, Duffield JA, Wang M (2003) The energy balance of corn ethanol revisited. Am Soc Agr Eng 46:959–968Google Scholar
  24. Sheehan J, Camobreco V, Duffield J, Graboski M, Shapouri H (1998) Life cycle inventory of biodiesel and petroleum diesel for use in an urban bus. National Renewable Energy Laboratory, NREL/SR-580-24089 UC Category 1503Google Scholar
  25. Government of Singapore (2008) Statistics Singapore. Available at http://www.singstat.gov.sg/. Accessed August 2008
  26. Spath PL, Mann MK (2000a) Life cycle assessment of a natural gas combined-cycle power generation system. National Renewable Energy Laboratory, NREL/TP-570-27715Google Scholar
  27. Spath PL, Mann MK (2000b) Life cycle assessment of a natural gas combined-cycle power generation system. Report no. NREL/TP-570-27715. National Renewable Energy Laboratory, WashingtonGoogle Scholar
  28. Spath PL, Mann MK, Kerr DR (1999) LCA of coal-fired power production. National Renewable Energy Laboratory (NREL), National Technical Information Service (NTIS), U.S. Department of Commerce, Washington, DCGoogle Scholar
  29. United Nations Statistics Division (2007) Environment statistics country snapshot: Singapore. UN Publications BoardGoogle Scholar
  30. Widiyanto A, Maruyama N, Kato S (2004) Life cycle analysis for electricity grid systems in Japan. Proceedings of 2nd International Energy Conversion Engineering Conference, August 16–19, Rhode Island, New England, USAGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Hsien Hui Khoo
    • 1
  • Reginald B. H. Tan
    • 2
  • Kevin W. L. Chng
    • 2
  1. 1.Institute of Chemical and Engineering Sciences (ICES)Jurong IslandSingapore
  2. 2.Department of Chemical and Biomolecular EngineeringNational University of SingaporeKent RidgeSingapore

Personalised recommendations