83 research outputs found
The role of the power/efficiency misconception in the rebound effect’s size debate: Does efficiency actually lead to a power enhancement?
No full textThis paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument. © 2008 Elsevier Ltd. All rights reserved
Complexity change and space symmetry rupture
No full textIs complexity growth the result of a continuous process or a sudden breakthrough? An increased energy density rate is the effect or the cause of a complexity leap? Should we approach complexity change by the perspective of components behaviour or system's space geometry? In this work we address some of the questions regarding the theoretical approach to complexity change. For this purpose a case study drawn by the productive structure and the transport system is considered. We would like here to propose an example in which the system structure is reshaped in a more energy intensive fashion as to increase the components' interactions due to a symmetry rupture in the space. Flows throughout the system are thereby incremented in a discontinuous way by a complexity leap. In the case study, we analyze how the productive system evolved its structure, between 1970s and 1990s, to increase interactions among its parts and thus further develop the transport sub-system. A two-stage shift has been considered: the fordian and the post-fordian productive structure. The second structure, given the same amount of parts, has been shown to increase the degree of freedom (path length and path diversity) of the system. The underlying evolutionary pattern is then analyzed. This evolutionary pattern relies on the hypothesis that thermodynamic evolutionary systems are characterized by an ever growing influx of energy driven into the system by self-catalytic processes that must find their way through the constraints of the system. The system initially disposes of the energy by expanding, in extent and in the number of components, up to saturation due to inner or outer constraints. The two counteractive forces, constraints and growing energy flux, expose the system to new gradients. Every new (spatial) gradient upon the system represents a symmetry rupture in the components' space. By exploring a new gradient, the system imposes further restrictions on its components and increases its overall degree of freedom. The counteractive effects of reduction/increase of degree of freedom concern two different hierarchical levels and occur at two different space and time scales. (C) 2009 Elsevier B.V. All rights reserved
Evaluation of the energy efficiency evolution in the European road freight transport sector
No full textIn this paper, we evaluate energy efficiency in the European freight transport sector over three decades, according to a variety of indicators, methodologies and databases. The aim is, on the one hand, of determining major drawbacks in energy efficiency metrics, on the other hand, identifying a possible trend in the sector. The present analysis shows that energy efficiency evaluation is generally subject to misinterpretation and distortion with regard to the methods and data source adopted. Two different indicators (energy intensity and fuel economy) were initially taken into account to select the most suitable for evaluating vehicles' efficiency. Fuel economy was then adopted and measured according to two different methodologies (top-down and bottom-up). We then considered all the possible sources of distortion (data sources employed, methods of data detection, speed of detection, power enhancement, size factor) with the aim of accomplishing a sound estimation. Fuel economy was eventually divided with the maximum power available (adjusted fuel economy), to account for the power shift of vehicles, that represents a further efficiency improvement. (C) 2009 Elsevier Ltd. All rights reserved
On the relationship between energy efficiency and complexity: insight on the causality chain
No full textThe relationship between the energy efficiency, energy density and complexity level of the system is here addressed from both thermodynamic and evolutionary perspectives. A case study from economic systems is presented to show that, contrary to widespread opinion, energy efficiency is responsible for energy growth and the complexity leap. This article further examines to what extent complexity, on a historical time scale, may evolve to counterbalance conservative effects brought about by energy efficiency. We analyze structural complexity growth by four different paradigms. An evolutionary pattern is then proposed that may encompass the broad dynamics underlying complexity growth. This evolutionary pattern rests on the hypothesis that thermodynamic evolutionary systems are featured from an ever growing influx of energy driven into the system by self-catalytic processes which must find its way through the constrains of the system. The system initially disposes of the energy by expanding, in extent and in number of components, up to saturation due to inner or outer constraints. The two counteractive forces, constraints and growing energy flux, expose the systems to new gradients. Every new gradient upon the system represents a symmetry rupture in components’ space. By exploring a new gradient the system imposes further restrictions on its components and increases its overall degree of freedom
The Rebound Effect: an evolutionary perspective
No full textThe rebound effect presents a major flaw in to energy conservation policies that aim to reduce energy consumption through energy efficiency development. Economics and energy related disciplines have thus far developed tools to measure such a phenomenon. This paper attempts to explain this seeming paradox using a thermodynamic-evolutionary theoretical framework in addition to the traditional economic approach. We here propose that evolutionary systems, such as biological or even economic systems, may rearrange themselves in a more complex fashion under the pressure of an increasing flux of energy, driven by the higher conversion rate of greater efficiency. Higher complexity, due to a greater energy density rate, counteracts the positive effects of energy efficiency. We investigated this hypothesis in the context of the road freight transport system. and the productive structure. The qualitative analysis in this paper, further substantiated by figures, provides a link between the dynamics of production patterns and the effect of efficiency in the light of the macro-economic effects of increased energy demand. The analysis departs from a rigorous investigation of the actual energy efficiency evolution in the road freight transport system to develop through a survey of the subsequent worldwide economic revolution in the production system, It is then shown how outsourcing, the key feature of globalization, can be identified as the main source of traffic density growth. Finally, four paradigms are used to stress how the shift in the production system must be considered a leap in structural complexity that consequently serves to increase the frequency of components' interactions. (C) 2008 Elsevier B.V. All rights reserved
The Prism of Elasticity in Rebound Effect Modelling: An Insight from the Freight Transport Sector
No full textIf the rebound effect is to be considered a major obstacle to sustainable freight transport, then action and timely policy must be made in advance. This, however, requires a theoretical understanding of the nature of the rebound effect and an empirical grasp of its underlying mechanism. Elasticity is the centrepiece of current models on the rebound effect (or Jevons paradox). Although elasticity is a metric of indisputable usefulness for empirical purposes, it may be misleading when applied to the complex rebound effect. Drawing on the parallel case of the ‘distance puzzle’ in international economics, it will be shown how elasticity can be misinterpreted or how it can misdirect an investigation of the phenomenon by following a predetermined mindset. This particular bias is shown to widen in the long term and evolving systems in which the elasticity metric continues to output a constant number, eliciting a persistent effect. Drawing on previous research, an alternative approach to studying the rebound effect based on complex network theory and statistical mechanics of networks will be described. It will be shown how the interplay between spatial and non-spatial effects in freight transport networks can inform us about the evolution of the effect of distances on trade relationships, upon which a new metric for the rebound effect can be built
Modelling the rebound effect with network theory: An insight into the European freight transport sector
No full textThis paper presents a two pronged approach to the study of the rebound effect, with the aim of assessing the magnitude of the effect in the European freight transport sector and proposing a new modelling framework based on network theory. The (direct) rebound effect is assessed with: 1) an econometric regression; 2) a model based on network theory and statistical mechanics. According to the econometric model the European road freight transport sector undergone a negative rebound between of −74% between 1998 and 2007 and −146% between 1998 and 2011. The network analysis delivers an estimation of network rebound ranging between −29.37% and −7.25. Overall, these results indicate that energy efficiency in Europe, between 1998 and 2011, succeed in reducing the energy consumptions amid an increasing demand for transports. Results on rebound estimation depend on the decision of using GDP as an exogenous variable, an assumption that leaves questions open about the causality chain between growth and transports. Furthermore, the network analysis highlights a structural change –a migration of production factors offshore, that might partially explain this negative effect. In this view, rebound effect analysis on a local or regional scale is becoming more and more uncertain in a globally interconnected economic context
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