Design, modelling and valuation of innovative dispatch strategies for energy storage systems

Energy storage has in recent years attracted considerable interest, mainly owing to its potential to support large-scale integration of renewable energy sources (RES). At the same time however, energy storage technologies are called to take over multiple roles across the entire electricity sector, introducing modern applications for both private actors and system operators. In this context, the current thesis focuses on the valuation of emerging energy storage applications, while also proceeding to the design and modelling of novel dispatch strategies, along with the development of financial instruments and support measures for the market uptake of energy storage technologies. In doing so, emphasis is given on mature, bulk energy storage technologies, able to support energy management applications. These include pumped hydro storage, compressed air energy storage and battery technologies. Energy storage applications/dispatch strategies examined are divided into three main categories that focus on private actors, autonomous electricity grids and utility-scale systems. For private energy storage actors, active, profit-seeking participation in energy markets is examined through the evaluation of high-risk arbitrage strategies. Furthermore, the interplay of energy storage and demand side management (DSM) is studied for private actors exposed to increased electricity prices and energy insecurity, designating also the potential for combined strategies of arbitrage and DSM. To reduce the investment risks associated with participation in energy markets, a novel aspect of collaboration between energy storage and RES is accordingly investigated for energy storage investors, proposing the use of storage for the delivery of guaranteed RES power during peak demand periods and stimulating the development of state support instruments such as feed-in tariffs. Next, attention is given on the introduction of energy storage systems in autonomous island grids. Such autonomous systems comprise ideal test-benches for energy storage and smart-grids, owed to the technical challenges they present on the one hand (e.g. low levels of energy diversity and limitations in terms of grid balancing capacity) and the high electricity production cost determining the local energy sector on the other (due to the need for oil imports). To this end, combined operation of RES with energy storage could, under the assumption of appreciable RES potential, prove cost-effective in comparison with the current solution of expensive, oil-based thermal power generation. Moreover, by considering the limited balancing capacity of such autonomous grids, which dictates the oversizing of the storage components in order to achieve increased energy autonomy, the trade-off between DSM and energy storage is next studied, becoming increasingly important as the quality of RES potential decays. With regards to utility-scale energy storage applications, the potential of bulk energy storage to support base-load RES contribution is investigated, proving in this way that the intermittent characteristics of RES power generation could be eliminated. This implies increased energy security at the level of national grids while also challenging the prospect of grid parity for such energy schemes. Furthermore, the market regulating capacity of utility-scale energy storage is reflected through the examination of different market-efficiency criteria, providing system operators with a valuable asset for the improved operation of electricity markets. Finally, the role of utility-scale energy storage in the optimum management of national electricity trade is investigated, designating the underlying problem of embodied carbon dioxide emissions’ exchange over cross-border transmission and paving the way for the consideration of energy storage aspects in electricity grid planning

A Survey on Cryptography Key Management Schemes for Smart Grid

A Smart grid is a modern electricity delivery system. It is an integration of energy systems and other necessary elements including traditional upgrades and new grid technologies with renewable generation and increased consumer storage. It uses information and communication technology (ICT) to operate, monitor and control data between the generation source and the end user. Smart grids have duplex power flow and communication to achieve high efficiency, reliability, environmental, economics, security and safety standards. However, along with unique facilities, smart grids face security challenges such as access control, connectivity, fault tolerance, privacy, and other security issues. Cyber-attacks, in the recent past, on critical infrastructure including smart grids have highlighted security as a major requirement for smart grids. Therefore, cryptography and key management are necessary for smart grids to become secure and realizable. Key management schemes are processes of key organizational frameworks, distribution, generation, refresh and key storage policies. Currently, several secure schemes, related to key management for smart grid have been proposed to achieve end-to-end secure communication. This paper presents a comprehensive survey and discussion on the current state of the key management of smart grids

Smart Grid Technologies in Europe: An Overview

The old electricity network infrastructure has proven to be inadequate, with respect to modern challenges such as alternative energy sources, electricity demand and energy saving policies. Moreover, Information and Communication Technologies (ICT) seem to have reached an adequate level of reliability and flexibility in order to support a new concept of electricity network—the smart grid. In this work, we will analyse the state-of-the-art of smart grids, in their technical, management, security, and optimization aspects. We will also provide a brief overview of the regulatory aspects involved in the development of a smart grid, mainly from the viewpoint of the European Unio

Community-based micro grids: a common property resource problem

This paper introduces a new methodological and theoretical foundation for studying the reasons for successes and failures of community-based micro grids (CBMGs). While technical and financial factors involved are very critical they are comparatively well researched. This analysis argues that further research into, in particular, the institutional design of CBMGs is required in order to improve long-term sustainability. The paper suggests that the electricity in an isolated micro grid can be treated as a common property resource (CPR), which then opens up the established academic literature regarding collective action in the presence of CPRs. More specifically this paper analyses how the rich set of enabling conditions for collective action, which has been established in the context of traditional CPR situations such as water for irrigation or pasture for grazing, can be applied to the context of CBMGs. The goal is to arrive at workable recommendations for policy-makers and practitioners to inform the design and improve the long-term sustainability of CBMGs. Ultimately this has the potential to contribute towards efforts to bring modern energy services to significant parts of rural populations without electricity access

Attributes of Big Data Analytics for Data-Driven Decision Making in Cyber-Physical Power Systems

Big data analytics is a virtually new term in power system terminology. This concept delves into the way a massive volume of data is acquired, processed, analyzed to extract insight from available data. In particular, big data analytics alludes to applications of artificial intelligence, machine learning techniques, data mining techniques, time-series forecasting methods. Decision-makers in power systems have been long plagued by incapability and weakness of classical methods in dealing with large-scale real practical cases due to the existence of thousands or millions of variables, being time-consuming, the requirement of a high computation burden, divergence of results, unjustifiable errors, and poor accuracy of the model. Big data analytics is an ongoing topic, which pinpoints how to extract insights from these large data sets. The extant article has enumerated the applications of big data analytics in future power systems through several layers from grid-scale to local-scale. Big data analytics has many applications in the areas of smart grid implementation, electricity markets, execution of collaborative operation schemes, enhancement of microgrid operation autonomy, management of electric vehicle operations in smart grids, active distribution network control, district hub system management, multi-agent energy systems, electricity theft detection, stability and security assessment by PMUs, and better exploitation of renewable energy sources. The employment of big data analytics entails some prerequisites, such as the proliferation of IoT-enabled devices, easily-accessible cloud space, blockchain, etc. This paper has comprehensively conducted an extensive review of the applications of big data analytics along with the prevailing challenges and solutions

Optimization of the operation of smart rural grids through a novel rnergy management system

The paper proposes an innovative Energy Management System (EMS) that optimizes the grid operation based on economic and technical criteria. The EMS inputs the demand and renewable generation forecasts, electricity prices and the status of the distributed storages through the network, and solves with an optimal quarter-hourly dispatch for controllable resources. The performance of the EMS is quantified through diverse proposed metrics. The analyses were based on a real rural grid from the European FP7 project Smart Rural Grid. The performance of the EMS has been evaluated through some scenarios varying the penetration of distributed generation. The obtained results demonstrate that the inclusion of the EMS from both a technical point of view and an economic perspective for the adopted grid is justified. At the technical level, the inclusion of the EMS permits us to significantly increase the power quality in weak and radial networks. At the economic level and from a certain threshold value in renewables’ penetration, the EMS reduces the energy costs for the grid participants, minimizing imports from the external grid and compensating the toll to be paid in the form of the losses incurred by including additional equipment in the network (i.e., distributed storage).Postprint (published version

Vulnerability Analysis of Modern Electric Grids: A Mathematical Optimization Approach

Electrical power must be transmitted through a vast and complicated network of interconnected grids to arrive at one’s fingertips. The US electric grid network and its components are rapidly advancing and adapting to the advent of smart technologies. Production of electricity is transitioning to sustainable processes derived from renewable energy sources like wind and solar power to decrease dependence on nonrenewable fossil fuels. These newly pervasive natures of smart technology and the variable power supply of renewable energy introduce previously unexamined vulnerabilities into the modern electric grid. Disruption of grid operations is not uncommon, and the effects can be economically and societally severe. Thus, a vulnerability analysis can provide decision makers with the ability to characterize points of improvement in the networks they supervise. This thesis performs a vulnerability analysis of electric grid operations including storage. This vulnerability analysis is achieved through a set of numerical experiments on a multi-period optimal power flow model including storage and variable demand. This model resulted in an analysis indicating storage is helpful in increasing resilience in networks with excess generation, no matter how severe the disruption. Networks with constrained generation benefit little, if at all, from storage. This analysis allows us to conclude careful implementation is the best way to improve electric grid security in the face of widespread use of renewable energy and smart technology

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15