Life Cycle Assessment

Environmental sustainability doesn’t just happen. It requires an understanding of the environmental "footprint" of a product, objective support for claims of environmental effectiveness, and a faculty for identifying targets for improvement.

NatureWorks LLC’s primary tool for measuring the sustainability of our products and operations is through Life Cycle Assessment (LCA). Recognized as an international standard-setting process via ISO 14040, LCA involves the compilation of a comprehensive inventory (Life Cycle Inventory, or LCI) of relevant inputs and outputs of a production system. For NatureWorks LLC, this means an evaluation and assessment of the potential environmental impacts associated with the processes as well as with all material and energy inputs and outputs of our NatureWorks® biopolymer (Polylactide - PLA) production system.

Since any discussion relies on definitions of terms let’s first review three key ones used within a Life Cycle Assessment.

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 or process. In addition to the eco-profile for NatureWorks® 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-to-pellet” or “cradle-to-biopolymer-factory gate” data.  An e-print of the eco-profile for NatureWorks® biopolymer is available online.

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). A 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 a LCI of a NatureWorks® biopolymer product. For a LCI one has to define among others the application, the production location and technology, the use phase and waste collection and processing.

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 a LCA is a LCI. In the life cycle assessment the inventory data is converted into a series of impact categories, such as fossil energy use, climate change and acidification, followed by an assessment of how relevant these impacts are.

LCA is a methodology providing data. It is one of the tools that can be used to evaluate a complete system. As an example, if a customer is making the evaluation to switch from biopolymer A to biopolymer B, the alternative biopolymer has to perform from a technical and an economic perspective, but some customers also want to evaluate the environmental perspective in more detail and LCA is the tool that can be used. This evaluation can consist of just sharing the numbers for fossil energy use and climate change up to setting up a full peer reviewed LCA, performed by an external LCA Consultant.

NatureWorks LLC processes renewable raw materials to make our products. In order to perform LCA studies, we develop “cradle-to-factory gate” life cycle inventory data for all the processes from all farming inputs, including tractor fuel and seed, to our NatureWorks® biopolymer production system. This analysis also requires inventory data for all kinds of fuels, raw materials and operating supplies used in our production system. Recognizing that increased transparency is inherent in progress toward sustainability, NatureWorks LLC has undertaken peer-reviewed research evaluating all the inputs and outputs of the NatureWorks® biopolymer production system from the cradle (corn production) to the factory gate and published it as “The eco-profiles of current and near-future NatureWorks® polylactide (PLA) production” in the Industrial Biotechnology journal”.

NatureWorks LLC is focusing in its sustainability program on the reduction of the use of fossil fuel resources and climate change inducing emissions. Both are widely considered as two major challenges for the 21st century. By reducing fossil fuel resources, other emissions such as nitrogen and sulfur oxides, metals and volatile organics are reduced as well. NatureWorks® biopolymer moves away from fossil resources to renewable ones (field corn) to build the NatureWorks® biopolymer chain, and starting with our 2006 production, NatureWorks purchases renewable energy certificates (wind power) to offset a big part of the cradle-to-factory-gate greenhouse emissions and to support the growth of renewable energy production in the US (19th largest corporate purchases of green energy in 2006 in the US).

General Life Cycle Findings
Peer-reviewed and published LCA data indicates that NatureWorks® biopolymer requires fewer fossil resources and emits significantly less greenhouse gases than most of the traditional plastics.

• The cradle-to-factory-gate production process of NatureWorks® biopolymer currently uses 62-68% per cent less fossil fuel resources than the traditional plastic materials such as PET, PS, PP and PE. This reduction is mainly driven by the facts that no fossil fuel resources are required to build the biopolymer chain and that the required electricity is produced via wind power.
• With the purchase of wind power-based Renewable Energy Certificates (RECs) starting in 2006, NatureWorks® biopolymer further significantly reduced the already low emissions of greenhouse gases. Compared with the traditional plastic materials such as PET, PS, PP and PE, NatureWorks® biopolymer reduces greenhouse gas emissions by 80-90%.
• NatureWorks® biopolymer does not contain persistent, bio-accumulative and toxic chemicals.

Why Use Life Cycle Assessment?
NatureWorks uses LCA and compiles Life Cycle Inventories (LCI) for a variety of reasons:

• In general, the tool LCA is used to understand the life cycle of NatureWorks® biopolymer and the products made of it. This information is used for comparison of products made of other biopolymer materials and to make further environmental/economic improvements in the NatureWorks® biopolymer production chain. These would include process improvements and the selection of raw materials, energy sources, production locations and waste management routes.
• LCI data can be used to calculate contributions to particular impact categories. This information is used to benchmark environmental performance against the incumbent products.
• Published LCI/LCA data for NatureWorks® biopolymer can be used by external LCA practitioners (governmental agencies, academics, non-governmental organizations, customers and consumers) in performing and improving their own studies.