Modeling of energy storage: technical-economic investigation of gravity energy storage

Abstract

To address challenges associated with global climate change, several countries started restructuring their energy production systems. Policy makers are struggling to identify workable solutions to face the continuous increase of greenhouse gas (GHG) emissions. Alternative methods to the use of fossil fuels have been proposed to achieve sustainable energy systems; these include the development of renewable energy sources. This latter is projected to globally play a significant role in the energy portfolio. However, the increasing penetration of renewable energy in power systems entails several challenges due to the intermittent nature of these resources. Therefore, flexible options need to be implemented to overcome these issues. Examples of solutions include expansion of the electric grid, import and export of electricity, and management of the demand side. However, substantial interests in the deployment of energy storage technologies have been shown. These are mostly due to the increasing share of renewable energy systems, the need to balance the demand and supply of energy, as well as the high capital incurred for maintaining the reliability of power supply. The field of energy storage still requires more exploration and it is considered a subject of great interest for the development of renewable energy. A well proven storage technology that is commonly used is pumped hydro storage (PHS). However, such a system needs specific height difference which is not always available. Based on the well-established concept of this storage system, several types of hydraulic energy storage systems are under development among them gravity energy storage. Research is needed to investigate the realization of such storage technology. This is addressed in this work by combining technical, economic and political approaches. Models have been developed to examine the different aspects of this storage system which include profitability, feasibility, operation, behavior, and performance. In addition, political considerations and barriers have been discussed to complements these approaches. This thesis concludes that gravity energy storage is an attractive technology which offers interesting technical and economical perspectives. If energy storage is to play an effective role as part of a low carbon transition, research and development of new storage system is necessary. Barriers facing the development of such systems need to be considered.