Local Power Network Research Articles

Assessment of the Effectiveness of Energy Transfer for Shore-to-Ship Fast Charging Systems

Charging systems from shore to ship are typically designed based on a range of operational and design parameters, encompassing onboard power and propulsion needs, available charging durations, and the capacity of local power networks. In areas with weak grid infrastructure, onshore energy storage is often employed to facilitate high-power charging for vessels requiring short charging intervals. Nevertheless, incorporating on-shore energy storage adds complexity to the system, and the selection of system configuration can profoundly affect the efficiency of energy transfer from the grid to the vessel. This study presents a comparative analysis of energy efficiency among AC, DC, and Inductive shore-to-ship charging solutions for short-distance ferries utilizing both AC and DC-based propulsion systems. Findings illustrate that an increased reliance on onshore battery power correlates with decreased overall energy efficiency during the charging process. Thus, optimizing energy efficiency necessitates careful consideration when distributing the load between the grid and onshore battery. Results indicate that DC charging offers advantages over other solutions for AC-based propulsion systems in terms of energy efficiency. However, for DC-based propulsion systems, the most efficient solution may be either DC or AC charging, contingent upon the distribution of load between the grid and onshore battery. Furthermore, it is inferred that despite adding additional conversion stages and complexity to the system, the energy efficiency of inductive charging is comparable to wired schemes. Considering the added benefits of contactless charging, such as reliability, safety, and robustness, these findings advocate for the adoption of inductive charging as a promising solution.

Review of Community Solar in the United States of America

Due to the increase in demand for electricity during the last several decades and the fact that demand has to be satisfied, a number of power plants that work by utilizing fossil fuel sources have been built to satisfy the increased demand for electricity. As a result of the excessive use of fossil fuel sources, global warming and climate change have become serious issues that affect the entire world. The rise of those issues has put pressure on the entire world to switch from the use of fossil fuel sources energy to the use of green sources energy to generate electricity. Out of various renewable energy sources (wind, hydro, geothermal, and biomass), photovoltaics based on free fuel solar energy has emerged as the technology for generating lowest cost electricity. In addition to utility scale solar farms and rooftop solar, community solar benefits flow to multiple customers such as individuals, businesses, nonprofits, and other groups. The purpose of this paper is to provide a comprehensive review of community solar. A new business model of community solar is proposed where a photovoltaic system and battery energy storage system can work as standalone power system. Further cost reduction can be achieved if the standalone local power network works on direct current (DC) in place of alternating current (AC) power.

The challenge of commodity-centric governance in sacrifice frontiers: Evidence from the Brazilian Cerrado's soy sector

Conservation governance is increasingly globalized, particularly supply chain polices implemented by multinational corporations. However, the ways that local elite narratives and power networks influence the design and implementation of policies is poorly understood. We examine the role that local agribusiness narratives have on producers’ resistance to supply chain policies through the concept of the “sacrifice frontier”. We theorize sacrifice frontiers are regions where reinforcing perceptions that conversion of native vegetation has high economic potential and low conservation importance combine with rapid processes of wealth and power consolidation by agribusiness interests. We posit that these dimensions of a sacrifice frontier make rapid land use change and ongoing social and ecological harm especially probable as they reinforce constraints on sustainability governance. Here, we build on existing theories of environmental sacrifice through the case of the Cerrado biome, Brazil’s most active deforestation frontier. We argue that in the Cerrado, and other sacrifice frontiers like it, interventions that seek to reduce native vegetation loss cannot rely on supply-chain led policies, but instead need to foster more territorial multi-sectoral and multi-stakeholder discussions to alter the narrative of sociocultural and biodiversity sacrifice locally. We suggest this can be achieved by paying attention to local needs in a manner that is inclusive to all land users present within a targeted landscape.

A Comprehensive Review of Digital Twin Technology for Grid-Connected Microgrid Systems: State of the Art, Potential and Challenges Faced

The concept of the digital twin has been adopted as an important aspect in digital transformation of power systems. Although the notion of the digital twin is not new, its adoption into the energy sector has been recent and has targeted increased operational efficiency. This paper is focused on addressing an important gap in the research literature reviewing the state of the art in utilization of digital twin technology in microgrids, an important component of power systems. A microgrid is a local power network that acts as a dependable island within bigger regional and national electricity networks, providing power without interruption even when the main grid is down. Microgrids are essential components of smart cities that are both resilient and sustainable, providing smart cities the opportunity to develop sustainable energy delivery systems. Due to the complexity of design, development and maintenance of a microgrid, an efficient simulation model with ability to handle the complexity and spatio-temporal nature is important. The digital twin technologies have the potential to address the above-mentioned requirements, providing an exact virtual model of the physical entity of the power system. The paper reviews the application of digital twins in a microgrid at electrical points where the microgrid connects or disconnects from the main distribution grid, that is, points of common coupling. Furthermore, potential applications of the digital twin in microgrids for better control, security and resilient operation and challenges faced are also discussed.

Examining the Social, Civic, and Political Impact of Local Newspaper Closure in Outback Australia

Scholars across the globe have focused intently on mapping news deserts and gaps where public interest journalism is lacking or in peril. However, little attention is paid to understanding the impacts and changing media-related practices of people who live in communities that lose a designated news service—notably a local newspaper. This article draws on a focused ethnographic study of a small outback mining town, Lightning Ridge (population 2,284), in central New South Wales, Australia. The research was conducted over a two-month period and involved participant observation, 31 interviews with residents and relevant stakeholders, and examination of several media platforms relevant to the town. The article begins with an overview of Australian policy interventions to address the decline of public interest journalism. It then discusses the impact of a local newspaper’s closure via three themes—social, civic, and political. This is important because much of the policy focus in Australia is on the threat “news gaps” present to democracy. However, it is also necessary to understand the nuances of local media’s role in shaping everyday social connections and ritualistic practices and elevating issues to local networks of power. The article concludes by considering how current policy interventions can learn from failed attempts to fill the news gap in Lightning Ridge.

Co-planning of hydrogen-based microgrids and fuel-cell bus operation centers under low-carbon and resilience considerations

The hydrogen-driven fuel-cell electric buses, which bear the advantages of emission free, high storage content and long mileage range, provide a promising choice for decarbonizing the public transportation system. Also, the operation centers for fuel-cell electric buses can be upgraded as the hydrogen-based microgrids to achieve higher economic benefits and resilience levels. To support the low-carbon and resilience-oriented planning of microgrid-aided bus centers, this paper presents a two-stage robust optimization formulation with integer corrective decisions. In particular, the first-stage problem is to optimize the microgrid siting decisions as well as the capacity configuration of renewable-powered electrolyzers, fuel-cell stacks and hydrogen refueling stations for maximizing the annualized benefits. Then, a min–max problem is introduced in the second-stage to improve the load survival value subject to the planning decisions and the worst-case contingency scenario. Also, various corrective actions, e.g., the emergency response of fuel-cell electric buses using vehicle-to-grid functionality, the energy scheduling of stationary equipment in hydrogen refueling stations and the adaptive network reconfiguration, are considered for resilience enhancement of the local power network. As the resulting robust optimization formulation is with a challenging mixed-integer recourse structure, the nested column-and-constraint generation algorithm is designed. Numerical results on exemplary power network and public transportation system validate the effectiveness of the proposed planning methodology, which has the potential to be profitable under normal operations while improving the load survivability under severe disastrous occasions. Moreover, our customized nested column-and-constraint generation shows a satisfactory solution performance, which facilitates prompt disaster relief actions of energy-transportation network.

Sovereignty and Decentralization – two competing perspectives on the crisis of the French monarchy in the 16th century

The purpose of this paper is to analyze two significant treatises concerning the constitutional structure of the 16th century French monarchy, namely Jean Bodin’s Les Six livres de la République and Vindiciae, contra tyrannos written under the pseudonym of Brutus. The texts were answers to an ongoing institutional crisis of the monarchy, especially in light of the strictly connected issues of decentralization and the weakness of the royal administrative apparatus. The paper portrays how the tension between the royal administration and the complicated structure of the local networks of power not only rendered it impossible for both Bodin and Brutus not to take a stance on the matter but also how it influenced the shape of their theories. An analysis of how Brutus and Bodin tried to incorporate the complex institutional realities of the French kingdom into their own theories sheds some light on the authors’ attitude towards the functioning of the local centres of power, their theoretical disabling or using them on purpose; it also points to how much the actual decentralization of the state influenced the shape of the theories of both authors.

Residential energy trading with blockchain technology

Blockchain technology is a peer-to-peer value transfer technology that guarantees the safety and correctness of transactions between parties who do not trust each other without a universally trusted entity. Because of this characteristic, we study possible integration of blockchain technology with a local neighborhood power grid, to design a truly decentralized energy trading market. The proposed design allows energy producers within the local power networks to safely transact with neighborhood households. In other words, the users who have a redundant amount of power can sell it to users who need power at a fairer price, than is offered by a utility company. We show that such local trades provide benefits to both electricity buyers and sellers. This paper does two things: (1) establishes a mathematical game theory model for the users’ decision to buy or sell power in the peer-to-peer energy market and (2) discuss blockchain software stack for deploying such a system. For the first part, we use a smart algorithm built upon KKT conditions to solve the multi-level game theory model. Secondly, we show how the electricity price offered by the central company is influenced by the introduction of the blockchain to the power transaction system. As supporting evidence we provide experimental data—the simulation of the market and its infrastructure using blockchain Hyperledger’s Fabric framework. Finally, we found that the electricity price can decrease dramatically by allowing peer-to-peer transactions among prosumers and consumers unless the amount of generating power from prosumers is much lower than their demand. We foresee a great future for the applications of blockchain technology in this area with the increasing mass adoption of solar and renewable generation at the consumer level. However, these processes will enact more discussions on power delivery grid ownership and its public access, usage, and management.

IMPACT OF THE FOREIGN EXPERIENCE OF BOARD DIRECTORS ON THE PERFORMANCE OF PUBLICLY TRADED BRAZILIAN COMPANIES

ABSTRACT Purpose: We analyzed the impact of board directors with foreign experience on the accounting and market performance of companies listed on the Brazilian Stock Exchange (B3). Originality/value: We show unpublished empirical evidence about the relationship between the foreign experience of board directors and the performance of Brazilian firms. Knowing this relationship better contributes to the formulation of internal policies for the qualification of senior management, in addition to being valuable to shareholders, especially in a context of weak legal protection, as it is in Brazil. Design/methodology/approach: We collected data from 230 companies between 2010 and 2016, submitted it to unbalanced panel data regressions using the Systemic Generalized Method of Moments (GMM-Sys). Findings: The results suggest that the higher the proportion of board members with academic and professional foreign experience, the lower their accounting and market performance. This finding can be justified by institutional isomorphism, in which having an experience abroad would be a myth, a status institutionalized by the Brazilian society. In addition, foreign owners and directors face cultural barriers and would have less knowledge of the local environment, which would increase information asymmetries, impacting negatively in firms’ performance. On the other hand, an increase in the number of foreigners on the board positively influences the market value of companies, since, by having weaker local power networks and, consequently, less possibility to obtain private benefits, the investors could value companies with this characteristic.

System-Theoretic Process Analysis (STPA) for Hazard Analysis in Complex Systems: The Case of “Demand-Side Management in a Smart Grid”

Inelasticity of demand along with the distributed energy sources and energy market democratization pose significant challenges which have considerable negative impacts on overall grid balance. The need for increased capacity and flexibility in the era of energy market digitalization has introduced new requirements in the energy supply network which could not be satisfied without continuous and costly local power network upgrades. Additionally, with the emergence of Smart Homes (SHs) and Home Energy Management (HEM) systems for monitoring and operating household appliances, opportunities have arisen for automated Demand Response (DR). DR is exploited for the modification of the consumer energy demand, in response to the specific conditions within the electricity system (e.g., peak period network congestion). In order to optimally integrate DR in the broader Smart Grid (SG) system, modelling of the system parameters and safety analysis is required. In this paper, the implementation of STPA (System-Theoretic Process Analysis) structured method, as a relatively new hazard analysis technique for complex systems is presented and the feasibility of STPA implementation for loss prevention on a Demand Response system for home energy management, and within the complex SG context, is examined. The applied method delivers a mechanism useful in understanding where gaps in current operational risk structures may exist. The STPA findings in terms of loss scenarios can be used to generate a variety of safeguards to ensure secure operational control and in implementing targeted strategies through standard approaches of risk assessment.

Local Politics and State-Society Relations: State Officials, Local Elites, and Political Networks in Provincial Urban Centres in the 1930s and 1940s in Turkey

The historiography of Turkey has until recently exhibited a solid state bias in the study of the formative years of the republic. Conversely, the intersection of the state with local power networks has been understudied. This paper studies the dynamics of local political networks as exemplified in the case study of Esat Adil Müstecaplıoğlu, an exceptional case of a local political broker with leftist leanings in a provincial urban setting in the 1930s. Focusing on a local feud he was involved in and its aftermath, the article studies the dynamic relations, simultaneously conciliatory and conflictual, between local power brokers and state elites within local politics; how networks of patronage operated and shaped the relation between state and society. In doing so, the article explores the state’s infrastructural limits to operate without the cooperation of local power brokers and considers the significance of these dynamics for the ongoing Kemalist nation-building programme. Lastly, it argues that in appearing co-optive towards local elites the state acknowledged its low political legitimacy and the weakness of its ‘cultural constituency’—educated middle classes.

Power and energy analysis for a commercial retail refrigeration system responding to a static demand side response

The paper considers the impact of Demand Side Response events on the supply power profile and energy efficiency of widely distributed aggregated loads applied across commercial refrigeration systems. Responses to secondary grid frequency static DSR events are investigated. Experimental trials are conducted on a system of refrigerators representing a small retail store, and subsequently on the refrigerators of an operational superstore in the UK. Energy consumption and energy savings during 3 h of operation pre- and post-secondary DSR, are discussed. In addition, a simultaneous secondary DSR event is realised across three operational retail stores located in different geographical regions of the UK. A Simulink model for a 3Φ power network is used to investigate the impact of a synchronised return to normal operation of the aggregated refrigeration systems post DSR on the local power network. Results show ∼1% drop in line voltage due to the synchronised return to operation. Analysis of energy consumption shows that DSR events can facilitate energy savings of between 3.8% and 9.3% compared to normal operation. This is a result of the refrigerators operating more efficiently during and shortly after the DSR. The use of aggregated refrigeration loads can contribute to the necessary load-shed by 97.3% at the beginning of DSR and 27% during the 30 minutes of a DSR, based on results from a simultaneous DSR event carried out on three retail stores.

(Invited) Emerging Role of Silicon Carbide and Gallium Nitride Based Power Electronics in Power and Transportation Sectors

Free fuel-based energy sources (solar and wind) are demonstrating three long term trends in the electrification of sustainable energy. The three trends point toward a future in which sustainable energy is affordable, abundant and deployed with high energy efficiency. These three trends are going to have major economic, geo-political and environmental benefits to humanity. Driven by advancements in the technology of lithium batteries (cost reduction and increase in energy density), and the availability of low-cost sustainable clean electric power, the electrification of surface and air transportation is going through fundamental disruptive transformation. Volume manufacturing, similar to photovoltaic modules is mainly responsible for the cost reduction of lithium ion batteries. Doubling the volume of cumulative manufacturing leads to a cost reduction of about 22% in lithium ion batteries. Similar to Tesla’s Gigawatt factory in the United States, a number of manufacturers in China, Japan and South Korea are setting up ultra-large-scale manufacturing of lithium ion batteries. The long-term cost of supplying grid electricity from today’s lithium-ion batteries is falling even faster than expected, making them an increasingly cost-competitive alternative to natural-gas-fired power plants across a number of key energy markets. As an example, on March 28, 2019 Florida Power and Light in the United States announced that it would retire two natural gas plants and replace those plants with what is likely to be world’s largest photovoltaics-powered battery bank when it’s completed in 2021. Thus, without any doubt, both power and transportation sectors will provide phenomenal growth of power electronics in the 21st century. What role the silicon Carbide (SiC) and gallium nitride (GaN) based power electronics will play in the power and transportation sectors? The importance of SiC based power devices has been realized almost at the same time when silicon based low power devices were being developed in 50s. In the 21st century both SiC and GaN are drawing the attention as potential replacement of Si based power electronics and may open some new markets where Si based power electronics cannot function either due to power or temperature limitations. Public private funding agencies such as United States of Department of Energy have addressed the challenges and opportunities of wide band gap semiconductor power electronics [1]. According to a report from IHS market, the emerging market for SiC and GaN power semiconductors is expected to reach nearly $1 billion in 2020 [2]. While it is true that there exists a niche market GaN products, the phenomenal growth of WBG power electronics is questionable. To compare the cost of Si and GaN based products, we have plotted the cost of Si and GaN MOSFET’s as a function of volume of purchased devices in Figure [3, 4]. For 250 units (highest volume price listed in reference 4), the cost compared to a single GaN transistor has been reduced by 13.8 %. On the other hand, for 250 units, the cost of a single Si transistor is reduced by 35.6 %. Thus, cost is the major barrier in replacing Si based power electronics by WBG based power electronics. In an earlier publication [5], we have discussed the pathways that can lead to the reduction of manufacturing cost of WBG based products. Photovoltaics generates direct current (DC) power and batteries store DC power. As compared to alternating current power, at least 30 % capital cost and the cost of electric power is saved by local DC power networks. Direct current (DC) power enables fast charging of electric vehicles. Thus, the use of low voltage (<1,500 V) local DC power networks will further reduce the need of inverters but will need DC-DC converters. In this paper we will identify the WBG based key power electronics products that should be focused to see high growth of WBG based power electronics. Cost and performance of 48 V induction cooking device based on Si and GaN MOSFET switches will also be presented. References I. C. Kizilyalli, E. P. Carlson, D. W. Cunningham, J. S. Manser, Y. Xu, A. Y. Liu, March 13, 2018. Available at: https://arpae.energy.gov/sites/default/files/documents/files/ARPA-E_Power_Electronics_Paper-April2018.pdf .R. Aden, April 24, 2018. Available at: https://technology.ihs.com/602187/market-for-gan-and-sic-power-semiconductors-to-top-10-billion-in-2027Available at: https://lcsc.com/product-detail/MOSFET_International-Rectifier_IRFP260MPBF_International-Rectifier-IR-IRFP260MPBF_C2679.htmlAvailable at: https://www.mouser.com/ProductDetail/GaN-Systems/GS66508B-E01-MR?qs=etoTMWSvtH88Sj8NJfVvjg%3D%3D&gclid=EAIaIQobChMI1eHK4_O74QIVEYTICh2L3wLREAAYASAAEgKAzfD_BwER. Singh and A.A. Asif, ECS Transactions, 75(12), 11-18, 2016. Figure 1

Negotiating a Better Life: Emerging Trends in the Politics of Ordinary and Poor Muslims in Kolkata

Since Independence, Muslim politics in India has mainly been framed through the idiom of identity. While political engagements calling for democratization and increased participation in public life have occasionally occurred, scholarly interest in the ongoing shifts in Muslim political demands is recent and new. Simultaneously, the emerging literature on the politics of patronage and post-patronage networks in democracies of the Global South present anthropologists with new tools for studying the changing contours of the political mobilization of the urban poor. Using ethnographic narratives collected during fieldwork in Park Circus—one of Kolkata’s many Muslim-dominated neighbourhoods—which remains stigmatized and socially and spatially set apart, this article highlights the emerging modes of political engagement among poor and lower middle-class Muslims. I carefully document their efforts to negotiate a perceived ‘better’ life within a fast-changing neoliberal urban landscape that is prejudiced against them. For many ordinary Muslims, this has involved a movement away from the traditional elite-led politics of identity towards more plebeian forms of assertion and activism aimed at eking out a respectable living by working through extant structures of the local administration and networks of power in the neighbourhood.

Transformative and disruptive role of local direct current power networks in power and transportation sectors

The power sector is about to undergo a major disruptive transformation. In this paper, we have discussed the best possible energy solution for addressing the challenges of climate change and eradication of energy poverty. This paper focusses on the decentralized power generation, storage and distribution through photovoltaics and lithium batteries. It encompasses the need for local direct current (DC) power through the factors driving this change. The importance of local DC power in the transportation sector is also established. Finally, we conclude with data bolstering our argument towards the paradigm shift in the power network.

POLITISASI LINGKUNGAN OLEH AKTOR PERHUTANI DALAM KASUS KOPERASI TAMBANG INDONESIA III DI KABUPATEN MALANG, JAWA TIMUR

The existence of mining industry namely Koperasi Tambang III (KTI III) in Golo beach, Wojo Village, Gedangan, Malang District, brought negative impact socially and ecologically. Unfortunately, State Forestry Company (Perusahaan Umum Kehutanan Negara/Perum Perhutani) was involved to share their land as location of iron sand mining activity. Perhutani, as a State-Owned Enterprises (Badan Usaha Milik Negara/BUMN), has a contradicting roles at the same time, to manage natural resource of the forest and accumulate profit. The aim of this article is to depict the process of politization of environment done by Perhutani, based on dimensions (daily, episodic, and systemic), scales (local and regional), and power networks (local and regional). Through qualitative method with single instrumental case study approach, we find out that Perhutani has been the subject and object of politization by the bigger economic-political power. On three dimensions (daily, episodic, and systemic), we stated there are two configurations of Perhutani’s roles; first , politizing Golo beach through transform Resort Polisi Hutan (RPH). Second , Golo beach has politized by Malang Government as well as KTI III through transforming the Space Planing (Rencana Tata Ruang Wilayah/RTRW). On the local and regional scale, Perhutani seen by the local community and government, has brought not only the job opportunity, but on contrary the ecological damage. On the local power network, Perhutani was the subject to politize local community and government. However, on the divergent side, it was the object of politization done by KTI III and Malang Government.

Adaptive system model of stabilization of the power factor of actuators of centrifuges for uranium enrichment with structural dynamic model of electric drive with parallel reactive power compensation

Presents an engineering model of adaptive system of automatic stabilization of the power factor Cos φ = 1 as the condition of resonance at the frequency of power supply with parallel compensation of reactive power of electric drive of centrifuges battery of capacitors. The resonance in the power circuit corresponds to an extremum (minimum) of total current was taken as the goal of the algorithm automatic search. The operation of the adaptive control system in conjunction with a structural dynamic model of the object of optimization is presented modeling in terms of a Simulink (MATLAB). It is shown that in the process of automatic stabilization Cos φ = 1 excluded “overcompensation” in the local electric power network, including when disconnect blocs of the centrifuges. The adaptive control system is insensitive to additive errors of the sensor current I, can be realized general technical means and applied in general power networks.

Introduction

Introduction

Resilient and Secure Low-Rate Connectivity for Smart Energy Applications through Power Talk in DC Microgrids

The future smart grid is envisioned as a network of interconnected microgrids (MGs) -- small-scale local power networks composed of generators, storage capacities, and loads. MGs bring unprecedented modularity, efficiency, sustainability, and resilience to the power grid as a whole. Due to a high share of renewable generation, MGs require innovative concepts for control and optimization, giving rise to a novel class of smart energy applications, in which communications represent an integral part. In this article, we review power talk, a communication technique specifically developed for direct current MGs, which exploits the communication potential residing within the MG power equipment. Depending on the smart energy application, power talk can be used as either a primary communication enabler or an auxiliary communication system that provides resilient and secure operation. The key advantage of power talk is that it derives its availability, reliability, and security from the very MG elements, outmatching standard off-the shelf communication solutions.

Optimal power flow calculation for power system with UPFC considering load rate equalization

Unified power flow controller (UPFC) device can change system electrical quantity (such as voltage, impedance, phase angle, etc.) rapidly and flexibly under the premise of maintain security, stability and reliability of power system, thus can improve the transmission power and transmission line utilization, so as to enhance the power supply capacity of the power grid. Based on a thorough study of the steady-state model of UPFC, taking load rate equalization as objective function, the optimal power flow model is established with UPFC, and simplified interior point method is used to solve it. Finally, optimal power flow of 24 continuous sections actual data is calculated on a typical day of Nanjing network. The results show that the optimal power flow calculation with UPFC can optimize the load rate equalization on the basis of eliminating line overload, improving the voltage level of local power network.