1235688 (Skerlos). The objective of this project is to quantify the net greenhouse gas emissions associated with using carbon dioxide (CO2) as an input to sustainable manufacturing operations. CO2-based processes have been found to serve as excellent substitutes for processes utilizing large quantities of toxic and polluting materials in manufacturing. However, companies considering the on-site use of CO2 face an instant and major increase in "carbon footprint" according to current carbon accounting and life cycle assessment (LCA) methodologies. Current accounting and LCA practices make CO2 use appear unfavorable from a sustainability perspective when the import of CO2 to manufacturing operations can provide clear benefits to the economic, environmental, and social dimensions of sustainability. The intellectual merit of this research will be to advance the field of consequential life cycle assessment (cLCA) to enable estimation of the market driven emissions associated with the recovery and use of CO2 in sustainable manufacturing operations. Current economic allocation methods are inadequate for this purpose. Therefore an economic allocation methodology will be created that encompasses market forces, technology selection, and process substitution options. The cLCA methodology will then be exercised using life cycle modeling to permit an estimation of emissions associated with CO2 capture from various sources (e.g., the production of hydrogen, ammonia, and ethanol) as well as from different modes of transportation (e.g., trucking versus pipeline). Then regional supply burdens associated with the supply of recovered CO2 will be estimated for the entire US. Having addressed the supply-side emissions, the project will then estimate demand-side emissions associated with replacing existing manufacturing technologies with CO2 based technologies. Three case studies will be developed: semiconductor manufacturing, machine cleaning, and metalworking. Putting the regional supply side emissions together with the net demand-side emissions will allow the market driven emissions associated with recovered CO2 to be determined for sustainable manufacturing operations. We will extend the methodology to show how the framework for cLCA created for commodity gases can be extended to other commodity and pseudo-commodity materials (e.g., alloys of aluminum) used in sustainable design and manufacturing applications.
The broader impacts of this proposal will include advancements in the general field of cLCA, cLCA education for undergraduate, graduate, and distance learning students at the University of Michigan (UM), cLCA education for LCA students and practitioners world-wide, and the needed development of cLCA graduate student talent in the U.S. UM has recently launched a Program in Sustainable Engineering with a cornerstone undergraduate course in Sustainable Engineering. This course (CEE 265), which teaches approximately 125 students per semester (and growing), already teaches economic and environmental assessment methods and will in future directly teach the cLCA methods developed in this project. Graduate students taking Sustainable Design of Technology Systems (ME 589: approximately 130 students per year) will study the case studies of this project in depth and apply the cLCA methodology in their term projects. In addition to journal and conference publications, a web based portal to cLCA resources will be created that will include at least five 20-minute video short courses and case studies based on this research. As part of the broader impacts of the project, modifications will be proposed to the World Resources Institute and World Business Council for Sustainable Development accounting standards and also a working document will be developed to standardize the cLCA treatment of commodity gases in parallel with existing ISO LCA standards. It is also expected that, by challenging existing LCA and accounting treatments of carbon dioxide, it will be possible to promote the diffusion of CO2-based processes where appropriate as a sustainable manufacturing strategy. The project PI recently led the development of a cLCA methodology for consumer products with market driven design, a methodology that recently attracted national attention via its use to analyze Corporate Average Fuel Economy Standards. The development of an analogous cLCA methodology for industrial commodities, using similar economic methods, is a natural extension that can be anticipated to lead to significant research, education, and technology transfer impacts related to sustainable manufacturing and LCA.
