Security Of Electricity Supply Research Articles

Electricity supply in Ghana: The implications of climate-induced distortions in the water-energy equilibrium and system losses

An important synergy exists between electricity supply security and sustainable economic development. However, distortions in the water-energy equilibrium (especially for electricity systems that heavily depend on hydropower renewable energy) and operational inefficiency in the transmission and distribution networks can affect electricity supply negatively and distort this synergy. Given the irreversible nature of capital investments and the time-dependent nature of learning abilities and information flow, it is critical to delineate the short- and long-run effects of system losses and distortions in the water-energy equilibrium on electricity availability. This study applies an econometric approach to study the case of Ghana from 1970 to 2016. Distortions in the water-energy equilibrium negatively affect electricity supply in the short- and long-run. Investment in storage renewable hydro will ensure operational flexibility and compensate for the variability in water flow. Moreover, storage hydropower is a vital asset for the development of non-flexible renewables (i.e. wind and solar) due to the synergy that exists between them. System losses have a concave effect on electricity supply, with the tolerable rate determined as 6.65%. Current levels suggest that the country should cut down on system losses by 13.35%; this requires a significant investment in transmission and distribution networks and meters.

Shadow Pricing of Electric Power Interruptions for Distribution System Operators in Finland

Increasing distributed generation and intermittencies, along with the increasing frequency of extreme weather events, impose a serious challenge for electric power supply security. Understanding the costs of interruption is vital in terms of enhancing the power system infrastructure and planning the distribution grid. Furthermore, customer rights and demand response techniques are further reasons to study the worth of power reliability. In this paper, the authors make use of directional distance function and shadow pricing methods in a case study of Finland. The aim is to calculate the cost of one minute of power interruption from the perspective of the distribution network operator. The sample consists of 78 distribution network operators from Finland, and uses cost and network information between 2013 and 2015.

Shadow pricing of electric power interruptions for distribution system operators in Finland

Increasing distributed generation and intermittencies, along with the increasing frequency of extreme weather events, impose a serious challenge for electric power supply security. Understanding the costs of interruption is vital in terms of enhancing the power system infrastructure and planning the distribution grid. Furthermore, customer rights and demand response techniques are further reasons to study the worth of power reliability. In this paper, the authors make use of directional distance function and shadow pricing methods in a case study of Finland. The aim is to calculate the cost of one minute of power interruption from the perspective of the distribution network operator. The sample consists of 78 distribution network operators from Finland, and uses cost and network information between 2013 and 2015.

Cooperation or Localization in European Capacity Markets? A Coalitional Game over Graph Approach

Capacity markets, as a means to address the capacity adequacy issue, are constantly becoming an important part of the European internal electricity market. The debate focuses on how the capacity markets will be smoothly integrated in one Pan-European power market, without resulting in multiple national fragmentations and consequently in economic efficiency losses. Cross-border participation and regional cooperation are considered as two sine qua non conditions in this respect. The present paper provides a coalitional game theoretical approach aiming to facilitate the cooperation of neighboring countries, when it comes to the security of electricity supply and the necessity of establishing a capacity market. Such an approach can support respective decisions about capacity markets cooperation as well as stress-test the benefits considering all cooperation possibilities.

Can electricity companies be too big to fail?

The 2008 financial crisis has drawn attention to the concept of “too big to fail” companies, more recently relabelled "system-critical" institutions, referring to situations where the actual or near-bankruptcy of a company threatens the future of a service essential to the functioning of society. But such instances are not limited to the financial sector. We argue that if policymakers and regulators are not vigilant, a similar situation could occur in the electricity sector. So far this industry has only experienced occasional problems, but we can observe several precursory signals indicating that these problems might become more frequent. These include a tendency to globalisation in the absence of a supra-national regulator and the disruption caused by large amounts of renewable energies, resulting in companies being stranded with loss-making thermal generators. Still, these units are essential for the electricity supply security. We discuss several cases illustrating these trends. We conclude with a discussion of how electricity regulators and policymakers should approach the “too big to fail” problem, focussing both on preventive measures that can be taken to keep such a situation from occurring and on proactive actions aimed at avoiding a crisis once a system-critical company seems at risk of collapsing.

Approach for a Risk Analysis of Energy Flexible Production Systems

The steadily growing share of volatile renewable energies in power generation poses a major challenge for energy producers and consumers. One possibility for increasing grid stability and thus the security of electricity supply is Demand-Side-Management (DSM). Since a load adjustment in the manufacturing industry is often followed by an intervention in the production process, logistic targets in production can be adversely affected. In order to evaluate the risk that occurs for energy flexible manufacturing companies, an approach based on existing evaluation methods is developed.

Smart grids: enabler for the energy transition

This paper deals with the concept of “smart grids”. Starting from drivers behind the evolution of the power system, an overview of elements and technologies is given: smart grids have to intelligently integrate the actions of all users connected to it — generators, consumers and those that do both — in order to efficiently deliver sustainable, economic and secure electricity supplies. Examples of solutions from demonstration projects represent the base for discussing methodologies to estimate benefits deriving from smart grid solutions, showing how conflicting goals cannot always be fulfilled simultaneously. Finally, future perspectives are discussed: the main thinking regards the awaited pivot role for customers, in the future scenario with an increased utilization of electricity combined with a high penetration of non-programmable resources.

Hybrid Hydrogen and Mechanical Distributed Energy Storage

Effective energy storage technologies represent one of the key elements to solving the growing challenges of electrical energy supply of the 21st century. Several energy storage systems are available, from ones that are technologically mature to others still at a research stage. Each technology has its inherent limitations that make its use economically or practically feasible only for specific applications. The present paper aims at integrating hydrogen generation into compressed air energy storage systems to avoid natural gas combustion or thermal energy storage. A proper design of such a hybrid storage system could provide high roundtrip efficiencies together with enhanced flexibility thanks to the possibility of providing additional energy outputs (heat, cooling, and hydrogen as a fuel), in a distributed energy storage framework. Such a system could be directly connected to the power grid at the distribution level to reduce power and energy intermittence problems related to renewable energy generation. Similarly, it could be located close to the user (e.g., office buildings, commercial centers, industrial plants, hospitals, etc.). Finally, it could be integrated in decentralized energy generation systems to reduce the peak electricity demand charges and energy costs, to increase power generation efficiency, to enhance the security of electrical energy supply, and to facilitate the market penetration of small renewable energy systems. Different configurations have been investigated (simple hybrid storage system, regenerate system, multistage system) demonstrating the compressed air and hydrogen storage systems effectiveness in improving energy source flexibility and efficiency, and possibly in reducing the costs of energy supply. Round-trip efficiency up to 65% can be easily reached. The analysis is conducted through a mixed theoretical-numerical approach, which allows the definition of the most relevant physical parameters affecting the system performance.

Beyond smart grid—cyber–physical–social system in energy future [point of view

Smart grids (SGs) are electric networks that use innovative and intelligent monitoring, control, communication, and self-healing technologies to deliver better connections and operations for generators and distributors, flexible choices for prosumers, and reliability and security of electricity supply. SGs are a complex cyber–physical system by their very nature, and this has impacted the way energy is generated, transported and used. In our 2016 paper [1] , we examined the SG concept in the context of cyber–physical systems (CPSs), and outlined the challenges ahead alongside with fast development of advanced technologies such as Internet of Things, cloud computing, big data and complex networks.

Evaluation of electricity supply sustainability and security: Multi-criteria decision analysis approach

Electricity supply plays a significantly important role in national economy and society development. Accordingly, the evaluation of electricity supply sustainability and security as an early warning method is beneficial for the decision-makers/policy-makers to take various measures to enhance electricity supply sustainability and security. This study aims at developing a multi-criteria decision analysis framework for electricity supply sustainability and security evaluation, and a total of nine metrics (i.e. Shannon-Weiner index, electricity import dependence, supply adequacy, rural electrification rate, electric power losses ratio, residential consumption ratio, electricity per Gross Domestic Product, electric power consumption per capita, and fossil fuel dependence) in four dimensions including availability and security of supply, affordability and reliability, energy and economic efficiency, and environmental stewardship were employed for electricity supply sustainability and security evaluation. Fuzzy Analytic Hierarchy Process which allows the users to use linguistic terms to express their opinions was used to determine the weights of the criteria which represent their relative importance in the evaluation of electricity supply sustainability and security. Grey Rational Analysis was used to prioritize the status of electricity supply sustainability and security of different countries in different years. The electricity supply sustainability and security of the five major emerging national economies (Brazil, Russia, India, China and South Africa) was studied in Chinese perspective by the proposed method.

Energy Storage and Power Electronics Technologies: A Strong Combination to Empower the Transformation to the Smart Grid

The electric power industry is facing unprecedented transformations and challenges with the implementation of the smart grids. This new grid paradigm has arisen to build a flexible electric power system that better coordinates energy resources and loads aiming at efficiently delivering sustainable, economic and secure electricity supplies. As a part of the smart grids (SGs), microgrids (MGs) have been developed to exploit the full benefits from the integration of distributed energy resources, especially distributed renewable generation based on variable and intermittent sources, such as wind and solar. Nevertheless, meeting all these goal requires the implementation of innovative energy storage technologies integrated with high efficiency and very fast response electronic power conditioning systems to interface with the electrical grid. Power electronics systems play a key role in regulating the raw energy from energy storage systems (ESSs) and connecting to the electrical grid. Hence, this paper performs a comprehensive analysis of major technologies in electrical energy storage systems and their electronic interface for applications in smart grids. The work provides a complete study of the technology profile of both energy storage and power electronics suitable for applications in the evolving grid.

A Review of Wireless and Satellite-Based M2M/IoT Services in Support of Smart Grids

The Smart Grid (SG) is an evolution of the electricity network that dynamically integrates the activities and energy control of power consumers, power generators, distribution systems, and devices connected to the grid (e.g., substations, transformers, and so on). The goal of the SG is to economically and efficiently deliver a sustainable, reliable, and secure electricity supply. Machine-to-Machine (M2M) technology is designed for automated data exchange between devices, and thus has applicability to SGs. With M2M technology, organizations track and manage assets; inventories; transportation fleets; oil and gas pipelines; mines; wide-spread infrastructure; natural phenomena such as weather conditions, crop production, forestry condition, and water flows; and, as noted, SGs. Wireless communication is a staple of M2M. These wireless technologies range from unlicensed local connectivity, to licensed 3G/4G/5G cellular, to Low Earth Orbit (LEO) satellites. All of these technologies are relevant to the SG. Utilities have started to gradually support M2M and Supervisory Control And Data Acquisition (SCADA) systems over satellite links. This article focuses on wireless and satellite-based M2M services, as applicable to the Smart Grid, including the use of Internet of Things (IoT), particularly for the transmission and distribution (TD some comparisons to wireline solutions are also discussed.

Model to simulate medium-voltage active networks with an aggregated view of the low-voltage ends

The integration of renewable energy sources into distribution networks requires a significant change in the traditional planning and operational approach. In medium-voltage (MV) networks, in order to guarantee reliable and secure electricity supply, fostering the connection of new generation, some smart techniques, are based on the integration of operation practices in the set of possible planning alternatives, are being studied. In low-voltage (LV) networks, where distributed generation (DG), mainly photovoltaic producers, are connected in proximity to existing consumers, similar smart control techniques are being considered, either on the producer side (for instance reactive power control) or on the load side (active demand management). One of the main problems associated to the massive connection of DG is represented by the voltage quality. This study aims to describe and apply a model to simulate MV networks, while studying the maximum voltage variations in the underlying LV networks.

Assessing the risk profile to security of supply in the electricity market of Great Britain

Security of electricity supply has been an important topic of growing concern in the United Kingdom as the margin of supply over demand tightens and the risk to security of supply widens. The risk profile to security of supply is presented, in the United Kingdom, in terms of the conventional metrics capacity margin and loss of load expectation. However, increasing levels of disruption in the power sector, arising from a combination of policy, technological and customer change, challenge this traditional approach to characterise the risk to security of supply. The paper presents a framework to evaluate the risk profile to security of supply through a series of probabilistic metrics that establish the expected magnitude (power and energy), likelihood, frequency and duration of encountering supply shortfalls. This detailed characterisation of the risk profile enables risks to be fully identified, assessed and prioritised facilitating effective risk management.

Quantitative analysis on the impact of nuclear energy supply disruption on electricity supply security

Improvement of power supply security is of paramount importance to sustain human activities. Technical and engineering failures of power grid system have been analyzed to evaluate power system reliability hitherto. However, after Fukushima nuclear accident, the sudden electricity supply disruption particularly associated with nuclear energy utilization brings upon a new risk of electricity supply security arising from societal issues, or nuclear vulnerability. As such, a methodology of quantifying nuclear vulnerability is firstly established under varying both the magnitude and time instant of sudden stoppage of nuclear power operation. Through the nuclear vulnerability analysis, a new electricity supply security index dedicated for nuclear power utilization, named System Interruption Nuclear Vulnerability Index (SINVI) is developed. SINVI could be used to predict the risk of electricity supply disruption arising from the sudden stoppage of nuclear power operation corresponding to the different capacity combination of various energy sources. Finally, the widely proposed dimensions of energy security for undisturbed electricity supply – diversification and redundancy – are incorporated with nuclear vulnerability to design the more secured power system taking into account the risk of nuclear energy utilization. The established algorithm can be readily implemented in any other electricity grid network including nuclear power technology.

Flexible operation of thermal plants with integrated energy storage technologies

The energy system in the EU requires today as well as towards 2030 to 2050 significant amounts of thermal power plants in combination with the continuously increasing share of Renewables Energy Sources (RES) to assure the grid stability and to secure electricity supply as well as to provide heat. The operation of the conventional fleet should be harmonised with the fluctuating renewable energy sources and their intermittent electricity production. Flexible thermal plants should be able to reach their lowest minimum load capabilities while keeping the efficiency drop moderate as well as to increase their ramp up and down rates. A novel approach for integrating energy storage as an evolutionary measure to overcome many of the challenges, which arise from increasing RES and balancing with thermal power is presented. Energy storage technologies such as Power to Fuel, Liquid Air Energy Storage and Batteries are investigated in conjunction with flexible power plants.

Automated energy management in distributed electricity systems: An EEPOS approach

ABSTRACTThe increasing capacity of distributed electricity generation brings new challenges in maintaining a high security and quality of electricity supply. New techniques are required for grid support and power balance. The highest potential for these techniques is to be found on the part of the electricity distribution grid.This article addresses this potential and presents the EEPOS project’s approach to the automated management of flexible electrical loads in neighborhoods. The management goals are (i) maximum utilization of distributed generation in the local grid, (ii) peak load shaving/congestion management, and (iii) reduction of electricity distribution losses. Contribution to the power balance is considered by applying two-tariff pricing for electricity.The presented approach to energy management is tested in a hypothetical sensitivity analysis of a distribution feeder with 10 households and 10 photovoltaic (PV) plants with an average daily consumption of electricity of 4.54 kWh per household and a peak PV panel output of 0.38 kW per plant. Energy management shows efficient performance at relatively low capacities of flexible load. At a flexible load capacity of 2.5% (of the average daily electricity consumption), PV generation surplus is compensated by 34–100% depending on solar irradiance. Peak load is reduced by 30% on average. The article also presents the load shifting effect on electricity distribution losses and electricity costs for the grid user.

CO2-to-X and Coal-to-X Concepts in Pulverized Coal Combustion Power Plants

An increasing supply of fluctuating renewable energy sources especially in Germany requires highly flexible conventional power plants in combination with electricity storage to ensure the security of electricity supply. Different options are introduced to improve the part load capability of existing base-load pulverized coal combustion power plants (PCPP). Two concepts are CO2-based methanol synthesis (“Power-to-X”) or small-sized coal-based syngas production (“Annex”). Both act as a power sink during low electricity prices. The net power output of the total plant can be reduced so that lifetime-consuming start-ups and shutdowns of the PCPP become no longer necessary. The techno-economic study compares the concepts regarding efficiency, CO2 emissions, specific investment costs and production costs for methanol generation.

Interdependencies in security of electricity supply

The analysis of security of electricity supply (SoES) is particularly complex due to, among others, the liberalisation process and the increasing penetration of renewable energies. Larsen et al. [1] propose a framework based on twelve dimensions to evaluate SoES for a single jurisdiction. However, actions aimed at improving one dimension might impact others negatively, adversely affecting the overall system. Understanding how these dimensions are interrelated is thus a prerequisite for appropriate planning and resource allocation. We apply a Cross Impact Analysis (CIA) to these dimensions to determine the degree to which the different dimensions depend on each other. From this we derive an influence diagram to visualise the interdependencies and a scatter plot to categorise the dimensions as independent, driver, connector or outcome. Actions targeting the drivers or connectors are potentially the more effective ones a regulator can take, as the consequences will gradually ripple through the system. Having an integral view of the dimensions' interdependencies provides a better understanding of the higher-order changes an intervention may cause. This enables policymakers and regulators to identifying where in the system to intervene to achieve the desired effect with the least amount of resources and with as few undesirable side-effects as possible.

Value of gas network infrastructure flexibility in supporting cost effective operation of power systems

The electricity system balancing is becoming increasingly challenging due to the integration of Renewable Energy Sources (RES). At the same time, the dependency of electricity network on gas supply system is expected to increase, as a result of employing flexible gas generators to support the electricity system balancing. Therefore the capability of the gas supply system to deliver gas to generators under a range of supply and demand scenarios is of a great importance. As potential solutions to improve security of gas and electricity supply, this paper investigates benefits of employing flexible multi-directional compressor stations as well as adopting a fully integrated approach to operate gas and electricity networks. A set of case studies for a GB gas and electricity networks in 2030 have been defined to quantify the value of an integrated operation paradigm versus sequential operation of gas and electricity networks. The results indicate there are significant overall system benefits (up to 65% in extreme cases) to be gained from integrated optimization of gas and electricity systems, emphasizing the important role of gas network infrastructure flexibility in efficiently accommodating the expected expansion of intermittent RES in future power systems.