• Energy Research

Wave energy conversion is emerging as a promising technology for generating energy from renewable sources. Large-scale implementation of this technology requires the installation of parks of devices. We study the problem of optimizing the park layout and control for wave energy converters of the oscillating water column type. As a test case, we consider a device with a semi-submerged chamber and a Wells turbine working in the liquid phase. First, a novel model based on a nonlinear ordinary differential equation is derived to describe the behavior of the water column and used to estimate the power matrix of an isolated device. Then, its linearization is derived in order to enable the fast simulation of large parks with a high number of devices. The choice of the hydrodynamic model allows obtaining the gradient of the power with respect to the positions through an adjoint approach, making it especially convenient for optimization. We consider in particular the case of interaction with the piles of a floating wind energy plant. The results from the developed computational framework allow us to draw interesting conclusions that are useful when designing the layout of a park. In particular, we observe that interaction effects can be significant even in parks made up of devices of small size, which would exhibit negligible diffraction and radiation properties in isolated conditions, if the number of devices is large enough. Moreover, results show that wave reflection from the piles of an offshore platform can have positive effects on energy production.

Wave energy conversion is emerging as a promising technology for generating energy from renewable sources. Large-scale implementation of this technology requires the installation of parks of devices. We study the problem of optimizing the park layout and control for wave energy converters of the oscillating water column type. As a test case, we consider a device with a semi-submerged chamber and a Wells turbine working in the liquid phase. First, a novel model based on a nonlinear ordinary differential equation is derived to describe the behavior of the water column and used to estimate the power matrix of an isolated device. Then, its linearization is derived in order to enable the fast simulation of large parks with a high number of devices. The choice of the hydrodynamic model allows obtaining the gradient of the power with respect to the positions through an adjoint approach, making it especially convenient for optimization. We consider in particular the case of interaction with the piles of a floating wind energy plant. The results from the developed computational framework allow us to draw interesting conclusions that are useful when designing the layout of a park. In particular, we observe that interaction effects can be significant even in parks made up of devices of small size, which would exhibit negligible diffraction and radiation properties in isolated conditions, if the number of devices is large enough. Moreover, results show that wave reflection from the piles of an offshore platform can have positive effects on energy production.

This paper provides a synthesis and comparison of methodologies and results obtained in several studies devoted to the impact of climate change on hydropower. By putting into perspective various case studies, we provide a broader context and improved understanding of climate changes on energy production. We also underline the strengths and weaknesses of the approaches used as far as technical, physical and economical aspects are concerned. Although the catchments under investigation are located close to each other in geographic terms (Swiss and Italian Alps), they represent a wide variety of situations which may be affected by differing evolutions for instance in terms of annual runoff. In this study, we also differentiate between run-of-river, storage and pumping-storage power plants. By integrating and comparing various analyses carried out in the framework of the EU-FP7 ACQWA project, this paper discusses the complexity as well as current and future issues of hydropower management in the entire Alpine region.

This paper provides a synthesis and comparison of methodologies and results obtained in several studies devoted to the impact of climate change on hydropower. By putting into perspective various case studies, we provide a broader context and improved understanding of climate changes on energy production. We also underline the strengths and weaknesses of the approaches used as far as technical, physical and economical aspects are concerned. Although the catchments under investigation are located close to each other in geographic terms (Swiss and Italian Alps), they represent a wide variety of situations which may be affected by differing evolutions for instance in terms of annual runoff. In this study, we also differentiate between run-of-river, storage and pumping-storage power plants. By integrating and comparing various analyses carried out in the framework of the EU-FP7 ACQWA project, this paper discusses the complexity as well as current and future issues of hydropower management in the entire Alpine region.

Abstract Among the issues that are most relevant in the study of climate change (CC), hydropower plays a double role. On one hand, it will be affected by the change in water availability for hydropower plants. On the other hand, as the present major source of renewable energy, it is useful to support and increase the energy production and to reduce the human induced CC. The aim of the activity presented in this paper is the impact evaluation of expected CC on future reservoir control, the assessment of variations in hydropower production, and the identification of possible changes in water management. This activity is part of ACQWA project whose aim is the use of advanced modeling techniques to quantify the influence of CC on the major determinants of river discharge and to analyze their impact on society and economy. The activity has been focused on the development of a model of the management of a complex hydropower system as a function of climate conditions and electricity prices. The methodology was applied to a case study, the hydropower system in Valle d’Aosta Region in Italy. A conceptual scheme of the network of plants and reservoirs was developed and its optimal management was computed by means of a simple optimization tool, using energy prices and inflows as the main drivers of the system. The expected variations in reservoir management and power production were quantified through a comparison between optimization results of present and future years. Results show a statistically significant decrease in overall hydropower production; they give indications of variations in monthly production and interannual variability, causing an increase in water deficits and, as a consequence, in possible water conflicts among water uses. These results point out the limits of the current water policy and call for the introduction of a true integrated and adaptive approach.

Abstract Among the issues that are most relevant in the study of climate change (CC), hydropower plays a double role. On one hand, it will be affected by the change in water availability for hydropower plants. On the other hand, as the present major source of renewable energy, it is useful to support and increase the energy production and to reduce the human induced CC. The aim of the activity presented in this paper is the impact evaluation of expected CC on future reservoir control, the assessment of variations in hydropower production, and the identification of possible changes in water management. This activity is part of ACQWA project whose aim is the use of advanced modeling techniques to quantify the influence of CC on the major determinants of river discharge and to analyze their impact on society and economy. The activity has been focused on the development of a model of the management of a complex hydropower system as a function of climate conditions and electricity prices. The methodology was applied to a case study, the hydropower system in Valle d’Aosta Region in Italy. A conceptual scheme of the network of plants and reservoirs was developed and its optimal management was computed by means of a simple optimization tool, using energy prices and inflows as the main drivers of the system. The expected variations in reservoir management and power production were quantified through a comparison between optimization results of present and future years. Results show a statistically significant decrease in overall hydropower production; they give indications of variations in monthly production and interannual variability, causing an increase in water deficits and, as a consequence, in possible water conflicts among water uses. These results point out the limits of the current water policy and call for the introduction of a true integrated and adaptive approach.

Abstract Energy justice has reached a critical mass of contributions in recent years; nevertheless, different definitions of what energy justice is, appear to be competing, or at least they seem to be devoid of a theoretical effort at systematization of the concepts, an effort which could find a common theoretical root underpinning the current energy justice definitions. While tracing a common theoretical root might appear unnecessary to some, we argue that it contributes to strengthening the concept of energy justice and improves its suitability to application in policy design and policy evaluation. In this paper, we attempt to fill this gap, discussing how energy justice is embedded in the tradition of philosophical and political thought, with reference to the concept of equality. Further, we discuss the implications of this thesis.

Abstract Energy justice has reached a critical mass of contributions in recent years; nevertheless, different definitions of what energy justice is, appear to be competing, or at least they seem to be devoid of a theoretical effort at systematization of the concepts, an effort which could find a common theoretical root underpinning the current energy justice definitions. While tracing a common theoretical root might appear unnecessary to some, we argue that it contributes to strengthening the concept of energy justice and improves its suitability to application in policy design and policy evaluation. In this paper, we attempt to fill this gap, discussing how energy justice is embedded in the tradition of philosophical and political thought, with reference to the concept of equality. Further, we discuss the implications of this thesis.