vor 5 Jahren

02 | 2008

  • Text
  • Bioplastics
  • Fibres
  • Natureworks
  • Materials
  • Composites
  • Packaging
  • Automotive
  • Fibre
  • Plastics
  • Environmental

Politics PLA offers the

Politics PLA offers the additional options of industrial composting and chemical recycling. The end-of-life vision in the long term is to maintain a journey to zero waste – keeping the biopolymer, regardless of form, out of the landfill and being able to recycle into the same use or higher valued use if possible. NatureWorks biopolymer – marketed as Ingeo - is today predominantly used in food packaging, food serviceware and fiber-based products. Therefore the end products will be handled in current infrastructures, similar to the handling of PET, HDPE and other traditional polymers. Through innovation, technology and education NatureWorks LLC is looking to build a bridge to a better end-of-life. Today, there is immense value in increasing the use of PLA for food packaging and food serviceware especially where industrial composting has the potential to remove a large portion of the organic food waste stream from landfill disposal. So, where food composting infrastructure exists, PLA packaging and serviceware which is heavily contaminated with food waste can be composted assisting food waste diversion from landfill. These package/food waste streams are generated at many different places within the modern society such as quick-service restaurants, canteens, retailers, music festivals, sport arenas and households. To do this right, clear material identification and separation in the waste stream is required. However, it does not make environmental sense to stop here. While composting is superior to landfill – the fate of most food waste and packaging – it is still not a high form of recycling the carbon and the energy content present in the package. The real cradle-to-cradle potential for PLA is in higher-value applications via recycling. Besides applying mechanical recycling, PLA plastic can also be recycled back into lactic acid through chemical hydrolysis. In the future, as use increases significantly in multiple PLA applications, the demand for recycled PLA should contribute to the emergence of an economically sustainable recycled PLA (rPLA) market. Large-scale PLA recovery and conversion to lactic acid will fulfill the biopolymer’s promise of a closed-loop self-sustaining feedstock model. Summary of the results of the NatureWorks biopolymer eco-profiles Since the early nineties, PlasticsEurope has published the eco-profiles (see Appendix 1) for the traditional plastics. Since NatureWorks biopolymer is often compared in Life Cycle Assessment (Appendices 2 and 3) studies with these traditional plastics, the eco-profiles for current and near future NatureWorks biopolymer were calculated using the same methodology as developed by PlasticsEurope. Dr. Ian Boustead, the consultant of PlasticsEurope was contracted to guide and review the development of the NatureWorks eco-profiles. The NatureWorks eco-profiles were published in the peer reviewed journal Industrial Biotechnology in March 2007. This publication can be downloaded from the NatureWorks website. Two important NatureWorks’ objectives are the reduction of fossil energy consumption and greenhouse gas (GHG) emissions. Before executing the second objective, it is important to know where and in which quantities greenhouse gases are emitted in the production chain. This basic data was collected during the construction of the NatureWorks biopolymer eco-profiles drawing two conclusions: • 41% of the GHG were linked to electricity production used in the cradle-to-pellet production system and • the vast majority of the GHG were emitted during the lactic acid production phase, including the upstream contributions from the direct inputs such as electricity, natural gas, steam and raw material use. Therefore, NatureWorks LLC is following two tracks to reduce the GHG emissions and fossil energy use. The first track consists of the optimization of lactic acid process technology. Within the current technology used one could achieve further reductions using more energy efficient equipment, with changes in raw materials and in energy carriers and looking for on/off-site waste heat stream. Longer term, (2010+) it is the intention to implement major changes in lactic acid production and purification. These first track options are specifically related to those processes under the direct control of Cargill/NatureWorks and require additional technological development, a process which is underway and which will deliver future improvements. Optimized electricity production The second track consists of the optimization of electricity production. There are various methods to replace the electricity from the public grid, including: • On-site renewable generation such as solar photovoltaic systems, wind mills, and bio fueled heat/power installation; • Green power: purchasing both electricity + environmental attributes from a local supplier; and • Renewable energy certificates (RECs) (implemented since January 2006). The first options within the second track are not applicable today from a practical/economical point of view, but that does not mean they are not useful future options. 30 bioplastics MAGAZINE [02/08] Vol. 3

Concerning the second option, NatureWorks made the decision that beginning in 2006 it would purchase renewable based electricity to cover all electricity needs in the cradle-to-polymer-pellet production system. The preference is for the local utility to supply the Green Power directly. During 2006 limited volumes were available, but during 2007 already about 1/3 of the electricity required came from Green Power generated by the local utility. Since this was/is still not sufficient, NatureWorks LLC purchases so called Renewable Energy Certificates (RECs). In this case the renewable energy is not produced by the local supplier, but in a neighboring state which shares the same power grid. However, for the environment itself it does not make a difference where the renewable energy is being produced, as long as it is being produced in increasing quantities. NatureWorks LLC is purchasing RECs since the beginning of 2006 to cover all it electricity needs in its cradle-to-pellet NatureWorks biopolymer production system. NatureWorks LLC has calculated four eco-profiles (see box 1-3 for some explanation) for NatureWorks biopolymer (PLA) production: • PLA5: Represents the 2005 cradle-to-pellet Nature- Works biopolymer production system. • PLA6: Represents the current, 2006/2008, cradle-topellet NatureWorks biopolymer production system. In this eco-profile the fossil fuel-based electricity has been replaced by renewable energy-based electricity through investments in Green Power and RECs. • PLA/NG no WP: Represents the next generation (NG) cradle-to-pellet NatureWorks biopolymer production system. It includes the implementation of major changes in the lactic acid production and purification. This new technology will reduce energy and raw material use and co-product creation and is expected within 3-5 years. Electricity is imported from the public grid and is mainly fossil fuel-based. (‘no WP’ means that no wind or renewable power is used in this eco-profile). • PLA/NG: The same as PLA/NG no WP, but now Green Power is used to supply electricity in the Cargill / NatureWorks controlled production processes. This combination will make the cradle-to-pellet NatureWorks biopolymer a greenhouse gas sink. Renewable Energy Certificates - REC A REC represents the environmental attributes – for example the avoided CO2 emissions – that are created when electricity is generated using renewable resources instead of using fossil fuel sources. NatureWorks purchases Green-e certified RECs. The Center for Resource Solutions operates this certification and auditing program. A certified REC assures that the green energy is being produced and delivered, and that the attributes are being claimed only once. Green-e certified RECs also assure that they are from qualifying ‘new facilities’ (up to several years), Appendix: Politics PLA Plant East Green Grass 1) Eco-profile gives the total energy use, the total raw material use, the total air and water emissions and the total solid waste produced from the cradle to a factory gate. An eco-profile always starts with the extraction of the raw materials from the earth and ends with the production of the product of interest. Eco-profiles are not limited to a particular product. In addition to the eco-profile for Nature- Works biopolymer, eco-profiles can also be calculated for products like lactic acid, dextrose, corn, electricity and steam production. An eco-profile is the same as what is often referred to as ‘cradle-topellet’ or ‘cradle-to-polymer-factory gate’ data. 2) Life cycle inventory (LCI) gives the total energy use, the total raw material use, the total air and water emissions and the total solid waste produced from the cradle to the grave ( = the ultimate disposal). An LCI is basically the same as an eco-profile, but it covers the complete life cycle. So, the LCI of NatureWorks biopolymer ‘pellets’ does not exist, one can only have an LCI of a Ingeo product. For an LCI one has to define among others the application, the production location and technology, the use phase and waste collection and processing. 3) Life Cycle Assessment is a systems analysis tool to account for all the environmental impacts associated with a product or service, covering all stages in a product’s life, from the extraction of resources to ultimate disposal. The basic data set for an LCA is an LCI. In the life cycle assessment the inventory data is converted into a limited series of impact categories, such as fossil energy use, climate change and acidification, followed by an assessment of how relevant these impacts are. bioplastics MAGAZINE [02/08] Vol. 3 31

bioplastics MAGAZINE ePaper