Thermodynamic Input-Output Analysis of economic and ecological systems for sustainable engineering

It is widely recognized that conservation of natural capital is vital for sustainable development. However, techniques for evaluating natural capital flows are not yet satisfactorily developed. Traditional methods in engineering, economics and other disciplines tend to focus on economic capital while ignoring the contribution of ecological resources. In this dissertation a new thermodynamic approach is proposed that addresses this shortcoming. The new approach, called Thermodynamic Input-Output Analysis (TIOA), calculates degradation of energy quality in the economic and ecological stages of the production chain of a process or product. In this analysis energy quality is measured in terms of exergy or available energy. TIOA synthesizes data about natural and human resource consumption and emissions from various public domain databases. It uses concepts from systems ecology to determine exergy flows in the ecological stages and economic input-output analysis to determine exergy flows in the economic stages of a production chain. This dissertation applies TIOA to analyze the 91-sector 1992 and the 488-sector 1997 representations of the US economy. It calculates natural capital throughputs of individual industry sectors in terms of their Ecological Cumulative Exergy Consumption (ECEC). It also juxtaposes natural capital throughputs with economic capital throughputs by calculating ECEC/money ratios. These ratios indicate the discrepancy between thermodynamic work and the willingness of people to pay for economic goods and services. ECEC/money ratios are found to decrease from basic infrastructure industries to value-added service industries suggesting that the service industries are better at valuing ecosystem contribution than the resource extraction and manufacturing industries. These results are shown to have important implications to construction of pro-ecological macroeconomic policies. TIOA also calculates ECEC/ICEC ratios to determine the degree to which conventional thermodynamic techniques underestimate the contribution of ecosystems. The industry-specific ECEC/money and ICEC/money ratios are a major improvement over single economy-wide emergy/{dollar} ratios in emergy analysis and similar aggregate metrics in thermoeconomics. Such industry specific ratios are useful in hybrid thermodynamic analysis of industrial systems and provide a unique insight into their environmental implications. This has been illustrated by comparing alternative electricity generation systems. Industry specific ECEC/money and ICEC/money ratios are also useful in constructing the hierarchical thermodynamic metrics of sustainability. Such metrics have many desirable attributes of ideal sustainability metrics such as stackability, robustness, non-perverseness in indicating progress towards sustainability and communicable to diverse audiences and stake-holders. In the end, this dissertation proposes a multiscale statistical framework for Life Cycle Inventory (LCI) analysis. Such framework treats LCI as a statistical data fusion problem and ensures maximum utilization available data and models. It can also identify missing data, reconcile conflicting data and determine confidence bounds on LCA results by incorporating stochastic and subjective knowledge.