UVM Theses and Dissertations
Format:
Print
Author:
Hagens, Nathan John
Dept./Program:
Natural Resources
Year:
2010
Degree:
PhD
Abstract:
Energy sources require energy and non-energy inputs in order to find, process, and deliver services to society. The size and quality of the remaining 'net' energy is what powers modern civilization. As fossil fuels deplete this biophysical ratio of energy return on energy input (EROl) tends to decline, gradually freeing up less surplus energy for the productive economy. Due to its reliance on fiat currencies with no resource backing, standard economic analysis does not accurately account for this physical depletion of our resource base. As such, new biophysical frameworks that measure our balance sheet in natural resources terms would be of great value in assessing viable energy trajectories after hydrocarbons peak. However, biophysical analysis in general and EROl in particular are in need of further refinement and development if they are to be used as tools in the upcoming energy transition.
EROl analysis lacks a consistent framework and has yielded apparently conflicting results in the literature. A framework establishing appropriate boundaries of analysis is suggested in this dissertation that would make net energy and life cycle analyses commensurate across studies. Specifically, parsing EROl analysis into two different dimensions based on energy costs included and quantification of non-energy resource inputs (like water or land) would be of great value. Furthermore, incorporating the opportunity costs of internally produced and consumed energy stocks when applied to important chained production technologies would result in a more consistent application of net energy analysis.
Toward these ends, a comparative analysis for estimating the energy return on water invested (EROWI) for several renewable and non-renewable energy technologies reveals that the most water-efficient, fossil-based technologies have an EROWl one to two orders of magnitude greater than the most water-efficient biomass technologies, implying that the development of biomass energy processes in scale sufficient to be a significant source of energy may produce or exacerbate existing water shortages. Furthermore, when a time factor is introduced, many renewable technologies (e.g. wind and solar) experience a large handicap due to their frontloading of energy inputs (and investment).
Additionally, the omission of output variability ignores the preference for energy systems with stable returns and low dispersion versus equivalent returns that are intermittent or volatile. This has a direct relationship to many new energy technologies with outputs of much larger volatility in comparison to traditional energy sources. For instance, the impact of intermittence on the energy return of wind power is significant. Similarly, the constant flow of baseload electricity in the form of nuclear energy also undergoes a net energy handicap relative to fluctuating human demand systems.
This dissertation is a step towards accurate evaluation of our energy balance sheet in resource terms relative to societal demand and usage. By expanding the boundary conditions of net energy analysis to include non-energy inputs, as well as explicitly addressing the timing and risks of energy delivery systems, we can better assess our available means, and therefore invest more wisely in our energy future.
EROl analysis lacks a consistent framework and has yielded apparently conflicting results in the literature. A framework establishing appropriate boundaries of analysis is suggested in this dissertation that would make net energy and life cycle analyses commensurate across studies. Specifically, parsing EROl analysis into two different dimensions based on energy costs included and quantification of non-energy resource inputs (like water or land) would be of great value. Furthermore, incorporating the opportunity costs of internally produced and consumed energy stocks when applied to important chained production technologies would result in a more consistent application of net energy analysis.
Toward these ends, a comparative analysis for estimating the energy return on water invested (EROWI) for several renewable and non-renewable energy technologies reveals that the most water-efficient, fossil-based technologies have an EROWl one to two orders of magnitude greater than the most water-efficient biomass technologies, implying that the development of biomass energy processes in scale sufficient to be a significant source of energy may produce or exacerbate existing water shortages. Furthermore, when a time factor is introduced, many renewable technologies (e.g. wind and solar) experience a large handicap due to their frontloading of energy inputs (and investment).
Additionally, the omission of output variability ignores the preference for energy systems with stable returns and low dispersion versus equivalent returns that are intermittent or volatile. This has a direct relationship to many new energy technologies with outputs of much larger volatility in comparison to traditional energy sources. For instance, the impact of intermittence on the energy return of wind power is significant. Similarly, the constant flow of baseload electricity in the form of nuclear energy also undergoes a net energy handicap relative to fluctuating human demand systems.
This dissertation is a step towards accurate evaluation of our energy balance sheet in resource terms relative to societal demand and usage. By expanding the boundary conditions of net energy analysis to include non-energy inputs, as well as explicitly addressing the timing and risks of energy delivery systems, we can better assess our available means, and therefore invest more wisely in our energy future.