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Report Application News Meta-analysis of 30 LCAs Bio-based plastics convince with high climate protection potential and low use of fossil resources By Roland Essel Environmental Scientist nova-Institut Hürth, Germany and Michael Carus Managing Director nova-Institut Hürth, Germany The full study “Meta-analysis of life cycle assessments for bio-based polymers in the production of Proganic” (in German language only) can be downloaded free of charge at www.bioplasticsmagazine.de/201202 A meta-analysis of 30 life-cycle assessments by the nova-Institute for innovation and ecology on behalf of the Proganic company shows unambiguously positive results for the widespread biobased plastics PLA and PHA/PHB. Since bio-based plastics have increasingly established themselves and have been showing double-digit growth rates, there is a growing public discussion regarding whether these new plastics, that are based on biomass instead of mineral oil, really do, or do not, have ecological advantages. The Proganic GmbH & Co. KG company from Rain am Lech, Germany, which exclusively relies on bio-based plastics and has already managed to place different product lines such as garden and household goods on the market, wanted to figure it out exactly and entrusted the nova-Institut, Hürth, Germany, with conducting a comprehensive meta-analysis of PLA and PHA/PHB, thus answering the question of ecological assessment based on the latest state of scientific knowledge. Oliver Schmid, managing director of Proganic commented: “More and more customers are interested in bio-based solutions, but only in those that have distinct ecological advantages. We owe it to our customers to generate reliable data and make these available to them.” The Proganic ® material used by Proganic mainly consists of the biobased polymers PLA and PHB, therefore in the Meta-LCA the nova- Institut looked at PLA and PHA materials. The result of the meta-analysis of 30 life cycle assessments of PLA and PHA/PHB The production of the bio-based polymers PLA and PHA/PHB provides ecological advantages compared with the production of petrochemical plastics. The emission of greenhouse gases and also the use of fossil raw materials are definitely diminished. Therefore the substitution of petrochemical plastics with bio-based plastics yields positive impacts in the categories of climate change and depletion of fossil resources – two criteria that are playing a major role in current political and public discussion. Michael Carus, co-author and managing director of the nova-Institut, did express his surprise. “After the excited public debates of recent months we hadn’t expected such a clear result, the more so as bio-based plastics are still at the beginning of their development. So the meta-analysis not only shows the advantages already existing today, but also the substantial ecological potential as a result of further process optimisations.” 46 bioplastics MAGAZINE [02/12] Vol. 7
Report Figure 1 shows three ellipses, separated from each other, that represent the clusters of results. The ellipse on the upper right, which contains data based on using fossil resources of more than 70 megajoules per kilogram of plastics and greenhouse gas emissions of partly clearly more than three kilograms CO 2 equivalent per kilogram of plastics, correlates with petrochemical plastics. The other two ellipses illustrate the results of the bio-based plastics PLA and PHA/PHB, the data of which for the use of fossil resources are lower than 70 megajoules per kilogram of plastics. At the same time the greenhouse gas emissions of bio-based plastics amount to clearly less than three kilograms of CO 2 equivalents per kilogram of plastics. The ellipse of the PHA/PHB material exhibits a considerably wider spread of results than the ellipse of PLA. Figure 2 shows that the production of bio-based polymers, in comparison to all petrochemical plastics examined, leads to savings in fossil resources. The biggest savings potential can be found in comparison with polycarbonate (PC). The average savings potential in the production of PLA amounts to 56 ± 13 megajoules per kilogram of plastics here. The average savings potential in the production of PHA compared with PC amounts to 65 ± 25 megajoules per kilogram of plastics. But also in comparison with PP, HDPE, LDPE, PET and PS, average savings amounting to between 20 and 40 megajoules per kilogram of plastics are to be expected. Figure 3 shows that the production of bio-based polymers in comparison with the production of petrochemical plastics in most cases also leads to greenhouse gas emission savings. The biggest greenhouse gas emission savings can be found again when comparing bio-based polymers to polycarbonate (PC). For PLA, the average savings potential in this case amounts to 4.7 ± 1.5 kilograms of CO 2 equivalents per kilogram of plastics. For PHA, the average savings potential in this case amounts to 5.8 ± 2.7 kilograms of CO 2 equivalents per kilogram of plastics. In comparison with PET and Polystyrene (PS), considerable savings potentials ranging between 2.5 and 4.2 kilograms of CO 2 equivalents per kilogram of plastics are to be found in the production of bio-based polymers. The lowest savings potential are to be found when comparing biobased polymers with polypropylene (PP). Greenhouse gas emissions in kg CO 2 eq./kg 10 8 6 4 2 0 -2 -4 PLA Petroleum based polymers (PP, HDPE, LDPE, PET, PS, PC) 20 40 60 80 100 120 PHA Depletion of fossil resources in MJ/kg Figure 1: Comparison of the environmental impacts of different polymers and Proganic in the impact categories of climate change and fossil resource depletion Savings of fossil resources in MJ/kg 100 90 80 70 60 50 40 30 20 10 PLA PHA 0 Bio-based vs. PP Bio-based vs. HDPE Bio-based vs. LDPE Bio-based vs. PET Bio-based vs. PS Bio-based vs. PC Figure 2: Savings of fossil resources by the production of bio-based polymers in comparison with the production of petrochemical polymers Savings of greenhouse gas emissions in kg CO 2 eq./kg Proganic 9 PLA 8 PHA 7 6 5 4 3 2 1 0 -1 Bio-based vs. PP Bio-based vs. HDPE Bio-based vs. LDPE Bio-based vs. PET Bio-based vs. PS Bio-based vs. PC Figure 3: Reduction of greenhouse gas emissions due to the production of bio-based polymers in comparison with the production of petrochemical polymers bioplastics MAGAZINE [02/12] Vol. 7 47
