(338a) Comparing Resource Consumption and Sustainability of Biobased Materials Using Eco-LCA

Ecosystem goods and services are essential to all human activity.  In spite of this importance, the Millennium Ecosystem Assessment has found that many ecosystem services are highly degraded.  In many engineering analyses, these necessary goods and services are undervalued, or even ignored completely.  It is therefore crucial to develop and modify existing methods to allow these services to be valued and accounted for in decision making.  Conventional life cycle assessment (LCA) tends to only look at energy consumption and emissions.  However, Ecologically Based LCA (Eco-LCA) is a thermodynamically based LCA that allows for many ecosystem goods and services used throughout our economy to be quantified, in addition to the traditional LCA results of energy consumption and emissions. 

To create the Eco-LCA model, a nationally based economic model must first be obtained, to which the resources will then be added.  Eco-LCA uses the national input-output economic model that the Bureau of Economic Analysis provides every five years.  This current model, based on the 2002 national economy, shows the interactions between different industries and is used to track the use of ecosystem goods and services through the economy, which will be compared with previous research done to create an Eco-LCA inventory for the 1997 economic model.  Resource use must then be added to the model; this is done by finding values for resource use from government agencies and various research groups.  The thermodynamic properties of exergy and emergy allow for the many different units of ecosystem goods and services to be converted to the common basis of thermodynamic work.  This common basis means the results of Eco-LCA analyses can be aggregated and directly compared in metrics such as Cumulative Exergy Consumed and Percent Renewable.  After adding the ecosystem goods and services to the national economic model, resource intensities are calculated for every resource and economic industry by taking into account the resources entering the economy, the interactions between industries, and the total monetary activity of every industry.  This then provides a measure of individual and total resource use per dollar of economic activity in each industry.  These new resource intensities can be directly compared to the resource intensities from the 1997 Eco-LCA model and provide insight as to changes in both resource use and interactions between industries from 1997 to 2002.  

A case study will be presented using Eco-LCA to evaluate biobased materials such as biofuels and biopolymers.  The sustainability of biofuels will be discussed by investigating the resources required and emissions produced for various feedstocks, including changes since 1997. This will allow for a more dynamic view of the progress towards the most viable, sustainable biofuels.  Resource consumption to make biopolymers will be compared to traditional polymers, and conclusions will be drawn as to the most sustainable polymer materials.