『Abstract
Methods for investigating the role of energy in the economy involve
aggregating different energy flows. A variety of methods have
been proposed, but none has received universal acceptance. This
paper shows that the method of aggregation has crucial effects
on the results of the analysis. we review the principal assumptions
and methods for aggregating energy flows: the basic heat equivalents
approach, economic approaches using prices or marginal product
for aggregation, emergy analysis, and thermodynamic approaches
such as exergy. We argue that economic approaches such as the
index or marginal product method are superior because they account
for differences in quality among fuels. We apply various economic
approaches in three case studies in the US economy. In the first,
we account for energy quality to assess changes in the energy
surplus delivered by the extraction of fossil fuels from 1954
to 1992. The second and third case studies examine the importance
of energy quality in evaluating the relation between energy use
and GDP. First, a quality-adjusted index of energy consumption
is used in an econometric analysis of the causal relation between
energy use and GDP from 1947 to 1996. Second, we account for energy
quality in an econometric analysis of the factors that determine
changes in the energy/GDP ratio from 1947 to 1996. Without adjusting
for energy quality, the results imply that the energy surplus
from petroleum extraction is increasing, that changes in GDP drive
changes in energy use, and that GDP has been decoupled from between
aggregate energy use. All of these conclusions are reversed when
we account for changes in energy quality.
Keywords: Energy aggregation; Energy quality; Economy』
1. Introduction
2. Energy aggregation and energy quality
3. Economic approaches to energy quality
3.1. Price-based aggregation
3.2. Discussion
4. Alternative approaches to energy aggregation
5. Exergy
5.1. Emergy
6. Case study 1: net energy from fossil fuel extraction in the
US
6.1. Methods and data
6.2. Results and conclusions
7. Case study 2: causality in the energy-GDP relationship
7.1. Granger causality and the energy GDP relation
7.2. Cointegration and the energy GDP relation
8. Case study 3: the determinants of the energy-GDP relationship
9. Conclusions and implications
References