Decision making in energy [electronic resource] : advancing technical, environmental, and economic perspectives
Keywords: Mechanical Engineering

Today, with the supply of conventional energy resources being depleted at their fastest rates and the environmental impacts of their use better understood, there is an increasing desire to develop and employ alternative energy technologies that lessen dependence on these resources and reduce environmental impact. The ability to evaluate and compare potential technologies on a level playing field based on technical, environmental, and economic performance is essential to meeting these objectives while avoiding undesirable consequences. This dissertation presents a critical assessment of the existing methods for evaluating the technical and economic performance of energy systems, and introduces a new framework for evaluating environmental performance. The dissertation first considers the technical component of decision making. It is shown that, while all of the existing thermodynamic analysis techniques are well-established, significant subtlety is required in applying the techniques, understanding their capabilities, and interpreting their results for decision making. A detailed analysis of the production of Fischer-Tropsch liquids is used to illustrate many low-level issues associated with performing technical analysis of energy systems. These issues include the reliance on published data, empirical data, phase relationships, properties, analytical tools, and proprietary information. The analysis highlights that many of these issues are often not properly addressed in published studies and how oversights in these areas can adversely influence the decisions they inform. Following this low-level analysis, a service/carrier/resource view of the space in which energy systems operate is presented to discuss some of the considerations that are commonly not recognized when decision making across energy options. Across all levels of technical decision making, the utility of exergy is demonstrated as an analysis tool for evaluating energy options and providing performance information for decision making. Next, the dissertation considers the environmental component of decision making. In this consideration a new framework for evaluating environmental performance is presented. The framework utilizes the recent recognition that exergy is, in fact, a form of environmental free energy to provide a fundamental basis for valuing environmental interactions independent from their secondary impacts (e.g., global warming, photochemical smog, thermal pollution, etc.). In order to make this extension, modifications were required to the traditional representation of the environment and definition of the dead state used in technical exergy analysis. These modifications are accomplished through a combination of logical extensions and use of non-equilibrium thermodynamic principles. The framework is comprised of two separate analysis components: (1) environmental exergy analysis and (2) anthropocentric sensitivity analysis. Environmental exergy analysis extends the principles of technical analysis to the environment in order to quantify the locations, magnitudes, and types of environmental impact---state change, alteration of natural transfers, and destruction change. Anthropocentric sensitivity analysis enables the results of environmental exergy analysis to be further interpreted for decision making, but at the expense of introducing some subjectivity into the analysis framework. One of the key attributes of the analysis framework is its ability to evaluate and compare the environmental performance of energy systems on a level playing field, regardless of the specifics of the systems (such as resources, products, by-products, sizes, or time scales). The dissertation concludes with a discussion of the economic component of energy decision making. Recognizing the vast space of economics and energy, the discussion focuses on one of the many relevant dimensions of economic analysis---namely the influence costs and cash flow models have on the evaluation of energy systems. It is shown that the ability to accurately estimate the cost---both initial and future---of non-extant energy systems significantly influences economic performance metrics commonly used in decision making.