Rebecca L. Lankey

Life cycle assessment and green chemistry: the yin and yang of industrial ecology

The practice of life cycle assessment has been well documented as a tool for comparing products and processes or comparing various components within a life cycle. This paper addresses the question of how changes can be made once an assessment has been completed, such as identifying the improvements that can be made to address environmental problems and to decrease impacts on human health and the environment. Green chemistry, a fairly recent approach that addresses environmental concerns at a fundamental level, has already demonstrated examples of what we call ‘life cycle innovation’, that is, improvements at all stages of the product or process life cycle. This paper explores various applications of green chemistry methodologies to all stages of a product or process life cycle.

A Life-Cycle Comparison of Alternative Automobile Fuels

ABSTRACT We examine the life cycles of gasoline, diesel, compressed natural gas (CNG), and ethanol (C2H5OH)-fueled internal combustion engine (ICE) automobiles. Port and direct injection and spark and compression ignition engines are examined. We investigate diesel fuel from both petroleum and biosources as well as C2H5OH from corn, herbaceous bio-mass, and woody biomass. The baseline vehicle is a gasoline-fueled 1998 Ford Taurus. We optimize the other fuel/powertrain combinations for each specific fuel as a part of making the vehicles comparable to the baseline in terms of range, emissions level, and vehicle lifetime. Life-cycle calculations are done using the economic input-output life-cycle analysis (EIO-LCA) software; fuel cycles and vehicle end-of-life stages are based on published model results. We find that recent advances in gasoline vehicles, the low petroleum price, and the extensive gasoline infrastructure make it difficult for any alternative fuel to become commercially viable. The most attractive alternative fuel is compressed natural gas because it is less expensive than gasoline, has lower regulated pollutant and toxics emissions, produces less greenhouse gas (GHG) emissions, and is available in North America in large quantities. However, the bulk and weight of gas storage cylinders required for the vehicle to attain a range comparable to that of gasoline vehicles necessitates a redesign of the engine and chassis. Additional natural gas transportation and distribution infrastructure is required for large-scale use of natural gas for transportation. Diesel engines are extremely attractive in terms of energy efficiency, but expert judgment is divided on whether these engines will be able to meet strict emissions standards, even with reformulated fuel. The attractiveness of direct injection engines depends on their being able to meet strict emissions standards without losing their greater efficiency. Biofuels offer lower GHG emissions, are sustainable, and reduce the demand for imported fuels. Fuels from food sources, such as biodiesel from soybeans and C2H5OH from corn, can be attractive only if the co-products are in high demand and if the fuel production does not diminish the food supply. C2H5OH from herbaceous or woody biomass could replace the gasoline burned in the light-duty fleet while supplying electricity as a co-product. While it costs more than gasoline, bioethanol would be attractive if the price of gasoline doubled, if significant reductions in GHG emissions were required, or if fuel economy regulations for gasoline vehicles were tightened.

A hands-on approach to green design in an introductory engineering class

Few engineering schools offer students an opportunity to learn about the environmental implications of engineering design until late in the curriculum, if at all. However, such implications are becoming increasingly important and complex. Here, the authors describe how they have successfully implemented a hands-on group project for the first-year engineering education course which acquaints students with the concepts of green design. The objectives of the project were to reach students the basic ideas of life cycle analysis and environmentally conscious decision making and to encourage them to think about how products are designed. To examine the effectiveness of this project, a detailed survey was given to the students after the completion of the project. Overall, the project allowed students to discover for themselves the challenges of designing a product to be environmentally benign.