Abstract:The analysis of useful exergy (UE), which is the minimum amount of work required to produce a given end-use, provides insights on the relationships between structural changes and energy transitions because it focuses on what energy is used for, i.e., energy services, rather than where it comes from, i.e., energy carriers. In this paper, UE was accounted for Mexico in . It was found that UE experienced a six-fold growth, led by the increasing share of mechanical drive and electric energy uses. Structural changes such as industrialization and complete electrification mainly drove UE transitions. Technological progress, mainly driven by the industrial sector, and electricity availability caused an improvement in the aggregate final-to-useful efficiency of the economy. In addition, the trend of increasing UE economic intensity shows that Mexico became more dependent on UE per unit of economic output during industrialization. The results suggest that UE trends were more influenced by structural transitions while final exergy trends were more influenced by economic fluctuations. It is concluded that energy policy design in developing countries undergoing or starting the process of industrialization should focus on: (1) improvements in final-to-useful efficiency, especially of the transportation sector and (2) growth of the productivity of UE. Keywords: energy transitions; useful exergy; energy decoupling
IntroductionEnergy transitions describe the changes in energy quantity and quality and the way in which energy carriers ("either a substance or a phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes" [1]) are used in the economy [2,3]. These transitions, especially since the 18th century, are strongly related to wealth accumulation, population growth and improvements in the standard of living beyond Malthusian limits [4,5].A fundamental characteristic of energy transitions is that they are endogenous to the economic system, which means that they are both caused and effected by structural changes in the economy, see e.g., Grubler [6], , Feng et al. [8] and Rühl et al. [9]. Therefore, broader knowledge on these transitions may lead to adequate energy and environmental policies that boost sustainable development [10,11]. However, energy transition research has so far provided little understanding of economy-wide effects [12].One reason for this little understanding is that most research studies have been mainly focused on the primary and/or final level of energy use (see Figure 1) Another reason is the predominance of energy-based analysis in the literature compared to exergy-based analysis. Energy-based analysis takes into account the thermodynamic potential of an energy carrier, e.g., enthalpy. On the other hand, exergy-based analysis focuses on the maximum work that is theoretically obtainable from an energy carrier as it approaches equilibrium with its environment, i.e., exergy [20]. The latter analysis, as opposed to the former, is directly related to ...
