Power Supply Cost Research Articles

Coordinated Multi-Scenario Optimization Strategy for Park Photovoltaic Storage Based on Master-Slave Game.

Optimizing the operation of photovoltaic (PV) storage systems is crucial for meeting the load demands of parks while minimizing curtailment and enhancing economic efficiency. This paper proposes a multi-scenario collaborative optimization strategy for PV storage systems based on a master-slave game model. Three types of energy storage system (ESS) application scenarios are designed to comprehensively stabilize PV fluctuations, compensate for load transfers, and participate in the frequency regulation (FR) market, thereby optimizing the overall operational strategy of PV storage systems in parks. The upper-level objective is to maximize the park operators' profit, while the lower-level objective is to minimize the user's power supply costs. Case studies demonstrate that this strategy can significantly increase the economic benefits for park operators by 25.8%, reduce user electricity expenditures by 5.27%, and lower curtailment through a load response mechanism, thereby promoting the development and construction of PV storage parks.

Параметры, влияющие на стоимость продукции металлургических и трубопрокатных производств в различных регионах РФ

The article considers the market of oil products, the prices of which directly affect the cost of production of the strategically important pipe rolling industry, by years and regions. The geography of metallurgical enterprises location on the territory of the Russian Federation and regional zones are analyzed. Generalized indicators of the Russian steel pipe market are structured by key indicators and federal districts depending on average consumer energy prices in the domestic market. The geographical factor that most strongly influences the final cost of power supply to pipe rolling enterprises-consumers in price zones was identified.

Research and economic evaluation on novel pulse superconducting magnet power supply topology with energy storage for fusion devices

Large capacity fusion devices power supply poses a significant challenge to the stability of power grid, as it can lead to power outages and jeopardize the safety of fusion devices. And traditional distribution methods result in a significant waste of resources. This paper proposes novel topologies with integrated energy storage. In these topologies, high-amplitude pulsed power is supplied by the energy storage devices, while low-amplitude stable power is obtained from the grid. This decouples the pulsed power from power grid, and significantly reducing its impact. Moreover, it can reduce the design capacity of distribution equipment and lowers investment costs. To optimize the deployment of the energy storage device, a hybrid topology is proposed, which further reducing the cost of the novel power supply. Additionally, a cost model for the fusion power supply is developed and validated using simulation data from ITER. Through the case study shows that the HEPS topology saves more than 10 % of the investment cost and about 60 % of the annual operating cost compared to the traditional converter topology.

Potential of hydrogen and thermal storage in the long-term transition of the power sector: A case study of China

Hydrogen and thermal storage can reduce cost of long-term and large-scale energy storage with high efficiency and low or even zero carbon emissions. Their potential in the low-carbon transition pathway of an energy system with rapid growth of energy demand, large shifting of energy supply structure and limited investment budget remains unclear. A long-term power generation planning model is proposed in this paper, featuring detailed technical and economic characteristics of hydrogen and thermal storage. The power supply system of China is selected as a case study, due to its urgent need for low-carbon transition and complex spatial characteristics. Results show that the application of hydrogen and thermal storage can benefit the development of volatile renewable power generation technologies, facilitate the transition towards zero or even negative carbon emissions while simultaneously reducing power supply costs. Hydrogen is expected to be mainly produced in spring and consumed in summer while heat is expected to be primarily generated in autumn and consumed in winter. Shifting from thermal storage to hydrogen storage might happen around 2050 in accordance to the low-carbon transition progress.

An Assessment Method of Deviation Electricity Responsibility in China’s Forward Electricity Market Based on Time-Sharing Trading Prices

Electricity forward market contract trading constitutes a principal trading method in the electricity market. To address deviations from or non-compliance with contracts in China’s forward electricity market, an Energy Deviation Settlement (EDS) mechanism has been implemented. However, the current EDS mechanism is marred by unscientific penalties and imprecise deviation cost assessments. Consequently, this paper proposes a deviation responsibility assessment method based on time-sharing trading prices. Initially, the total annual contracted power is decomposed to derive the hourly deviation power for all 8760 h of the year. Subsequently, considering the power supply cost and load level, this paper proposes four pricing strategies for typical supply–demand scenarios and constructs a time-sharing trading pricing model based on cost pricing. Finally, this paper conducts a simulation using actual electricity data from China’s Province H. The results demonstrate that, compared to the traditional EDS mechanism, the proposed method can more accurately and reasonably measure the value of deviation responsibility. Concurrently, it can be better integrated with the future development of real-time spot market operations.

Energy scheduling method for island micro-grid system based on prediction model

Abstract Renewable energy, due to its characteristics such as volatility and intermittency, brings difficulties to the energy scheduling of renewable energy power generation systems. The main way of island power generation is to use renewable energy power generation. This chapter proposes a hierarchical energy scheduling method based on the prediction model through the research on the energy scheduling method of the island microgrid system to realize the energy optimization between the microgrid sub-systems, to achieve the maximum consumption of renewable energy for power supply, and to reduce the power supply cost and improve user satisfaction. The effectiveness of this method in improving the energy supply-demand balance of the microgrid sub-systems is verified through experiments.

Smart transportation systems using learning method for urban mobility and management in modern cities

The pressing demand for an escalation in renewable energy production arises from the surge in power consumption, escalating environmental concerns, and the exhaustion of fossil fuels. Microgrids, featuring dispersed power sources, exhibit superior resilience, efficiency, and stability in contrast to conventional power grids. Noteworthy investments in eco-friendly initiatives have been made by various major corporations, particularly in institutional structures. The current research advocates for the integration of photovoltaics, energy storage, and electric vehicles (EVs) as pivotal elements in a smart grid. This study introduces an optimal energy management system (EMS) designed to efficiently allocate power from existing sources. To address the challenges within an uncertain and reliable environment, a stochastic framework leveraging the whale optimization algorithm and unscented transform has been formulated. All simulations have been executed using the digital twin of the smart grid components. Results suggest that the proposed EMS ensures uninterrupted power supply, contributing to a substantial 45% reduction in energy costs. Furthermore, the potential of EVs as storage devices is explored. When employed as energy sources, EVs led to a noteworthy 45.58% reduction in power prices, while their use as loads still yielded a significant 19.33% decrease. The study also delves into the analysis of outage effects on the continuous power supply cost.

Multi-scenario research on the low-carbon transition in energy-deficient cities-view from the power supply side

Cities are the places where power supply demand is highly concentrated. How to ensure power supply security while realizing low-carbon transition is the key challenge faced by the construction of new power systems. In large cities with a shortage of local power generation resources, this problem is particularly prominent. The study takes Guangzhou city as a case study area, which has the typical characteristics of “serious energy shortage and extremely high-power load density” in China. This study explores the differences in power supply capacity, structure, carbon emissions, and power supply costs under the six different scenarios set up from the power supply side for future power supply structures. The optimal power supply modes have been matched for cities with different development characteristics and needs. The change in power supply structure and the realization path under the optimal power supply modes are discussed. The results show that the power supply capacity of Guangzhou is constantly improving under different scenarios, with the highest self-sufficiency rates of power production capacity and power production quantity reaching 80% and 50%, respectively, by 2030. Despite this, Guangzhou still does not have the basic conditions for building a new power supply system through the development of local high-proportion renewable energy only due to the limitation of resource endowment. The combination with increasing the ratio of renewable energy in outsourcing power is an inevitable choice for low-carbon transition for the city. This study provides a new idea on how to build a new power supply system for an energy shortage city. It can be used as a reference for safe power supply and low-carbon transition for the power supply sectors of other cities.

An Energy Storage Capacity Configuration Method for a Provincial Power System Considering Flexible Adjustment of the Tie-Line

A high proportion of renewable generators are widely integrated into the power system. Due to the output uncertainty of renewable energy, the demand for flexible resources is greatly increased in order to meet the real-time balance of the system. But the investment cost of flexible resources, such as energy storage equipment, is still high. It is necessary to propose a method for determining the capacity of energy storage scientifically. An optimization and planning method of energy storage capacity is proposed. It is characterized by determining the optimal capacity of energy storage by carrying out 8760 hours of time series simulation for a provincial power grid with energy storage. Firstly, the current situation of power supply and demand for provincial power grids is analyzed. The difficulty of realizing a power balance at different time scales is analyzed. Then, the source load balancing solutions at different time scales are proposed. The difficulty of a long-term power balance can be alleviated by flexibly adjusting the power on the tie-line of the provincial power grid. And the difficulty of a short-term power balance can be met through energy storage. In addition, an optimal planning model of an energy storage system is established with the power supply cost as the objective function. The optimal capacity of the energy storage is determined by comparing the objective function of different planning schemes. Finally, a case study is carried out. It is found that flexible adjustment of interprovincial interconnection lines can reduce the maximum demand for electricity from 8.439 billion kWh to 2.299 billion kWh. At the same time, the curtailment ratio of renewable electricity can be decreased from 12.6% to 5.0% by using energy storage. However, the average power supply cost of the system gradually increases from 0.307 CNY/kWh to 0.485 CNY/kWh. It is necessary to fully tap into the various values of energy storage equipment.

Prosumer solar power and energy storage forecasting in countries with limited data: The case of Thailand

Forecasts of distributed energy resource deployment are becoming increasingly important in electric power purchase plans and difficult for countries with limited data. This study utilizes the Customer Adoption Model to forecast the deployment of behind-the-meter distributed solar photovoltaics and battery energy storage systems until the year 2050 and Thailand is used as a case study of the countries with limited data. Comparing methods and results from this study with those used in past studies shows that methodological choices can produce diverging results that shape investment plans and the estimated cost of power supplies. Several input variables of the Customer Adoption Model are discussed that will require continuous refinements as more data become available. The results show that pairing solar systems with batteries could in principle accelerate solar deployment and carbon emissions reduction but the high cost of batteries lengthens the payback period, raising questions about forecasting methodologies that rely mainly on the payback period. The methodological contribution points to a “chicken-and-egg” problem between forecasting and policy uncertainties: accurate forecasting depends on policy certainty, but getting policy right depends on accurate forecasting. Integrated scenario construction and the determination of a specific timeframe for achieving the adoption goal can help policymakers understand the impacts of different policy designs on distributed energy resource deployment and overcome this problem.

Cloud Computing: a tool for effective records and information management system in Nigerian academic libraries

Academic libraries, as part of their traditional responsibility, engage in the collection and generation of data and records with a various degree of sensitivity and usefulness. This study examined the importance of library record and advocates for the implementation of cloud computing technology as a viable alternative to other mode of record storage. Cloud computing as a record management tool will help preserve the myriad of records generated from the daily activities of libraries. The paper also identified the danger of paper or electronic method of information storage. It argued that information stored in this format is susceptible to loss by theft, fire or computer viruses, hard drive collapse as well as the destruction of local library internet server due to poor maintenance culture on the part of the personnel. Apart from the data backup function, remote accessibility of these record is another key consideration for cloud computing utility in library record management. In view of the vast potential, especially in the area of its elastic storage capability, it is highly recommended for all academic libraries in the country. However, it is observed that the cost of data and irregular power supply are some of the challenges facing its adoption in Nigeria, as along with the vulnerability to cyber-attacks which may lead to a partial or total loss of record. In these regards, it is further recommended that cloud computing, as a service platform, is adopted as a backup platform rather than a sole tool for record and data management in academic libraries.

Optimal design method and benefits research for a regional integrated energy system

Regional integrated energy systems (RIES) have garnered increased attention because they highly utilize renewable energy, comprehensive efficiency, and flexible operation. However, the current research on RIESs is mainly based on burning natural gas and supplemented by renewable energy, which will consumes much primary energy and generates corresponding carbon emissions. Therefore, a RIES contained various renewable energy sources and station energy sharing was constructed in this paper. Both the collaborative optimization model, which considered the operating parameters and system configuration, and the hierarchical optimization model, which optimizes the equipment configuration at the upper layer and the operational parameters at the underlayer, were constructed, respectively. Taking a multi-function low-carbon park as an example, the isolated integrated energy system (IIES) and RIES performances were explored. Finally, the operation cost, carbon emission, and interactive power in the separated production system, IIES and RIES were analyzed and discussed from a long-short time scale perspective. The results showed that the carbon emission, interactive power, and energy supply cost of the RIES's unit area are 7.62 kg/m2, 10.07 kWh/m2, and 40.55 CNY/m2, respectively. Long time scale perspective (Years or months), RIESs could significantly reduce carbon emissions and interactive power. However, on a short time scale viewpoint (Hours), the system's instantaneous energy conservation and carbon reduction effect was general; meanwhile, the maximum grid-connected power in IIES and RIES was 2617.7 and 2712.0 kW, respectively.

Modeling of modes of traction power supply systems equipped with renewable energy sources

The article presents the results of research aimed at developing digital models for power flow analysis of railway power supply systems (RPSS) equipped with distributed generation (DG) units based on renewable energy sources. We employed the technique of modeling in the phase reference frame, which has the following features: system-wide consistency, which enables modeling power flows in a way that takes into account the properties and characteristics of a complex RPSS and the feeding power system; versatility, which allows for modeling of traction networks of various designs; comprehensiveness, which consists in the possibility of power flow analysis of normal, emergency, and special states of a RPSS, such as those occurring during de-icing of overhead contact system wires. Three groups of models have been developed. The first one was designed for power flow analysis RPSSs with DG units based on synchronous generators driven by mini-HPP turbines. It is also possible to apply this model in the case of inverter generation that uses photovoltaic panels. The second group of models provided simulation of RPSS power flows with induction generators. The third group enabled power flow analysis in the case where there are three-phase generators connected to a single-phase traction network by means of Steinmetz converters. Active harmonic conditioners and controlled reactive power sources were used to reduce the negative impact of inferior power quality on voltage deviations and harmonic distortion. Simulation results produced by the software package Fazonord showed that the following positive effects can be obtained on the basis of the use of RES-based DG units: reduced costs of power supply; reduced imbalance on the buses of district windings of traction substations, stabilization of voltage levels on bow collectors of electric locomotives.

The impact of electricity-carbon market coupling on system marginal clearing price and power supply cost.

In this study, we assessed the impacts of the benchmark designs of emissions allowance allocation in China's national carbon emissions trading system with plant-level data and further estimated the marginal clearing price and power supply cost in Guangdong power market under electricity-carbon market coupling with unit commitment and economic dispatch model. We find that the existing allowances benchmark would result in a considerable surplus of allowances at about 222 Mt. But the benchmarking and exemplary levels on the heat rate of power supply would motivate thermal power units to reduce CO2 emissions. Under a tight balance of supply and demand in Guangdong, peaking thermal power plants will become the marginal clearing units and higher clearing prices will add to the revenue of lower cost inframarginal renewable energy power units. However, the combined impact of electricity-carbon market coupling would cause the marginal clearing price fluctuates obviously from 0 to 1159 CNY/MWh. Compared to the baseline scenario with free CO2 allowances allocation, the efficiency of thermal power utilization would decrease by 23%-59% and the net revenue per MWh power supply of coal-fired power units would decrease by 275%-325% under the stress scenario. Our study suggests that setting a more stringent allowances allocation benchmark for carbon price discovery is necessary. As electricity-carbon market coupling changes the role of coal-fired power plants to provide flexibility service and decrease their revenues, it calls for further market designs on proper reimbursement of flexible resources, under which the electricity market can effectively achieve the synergy among accommodating new energy, ensuring resource adequacy, and delivering cost efficiency. In addition, the synergy can be enhanced by formulating a tax program, which can promote renewable energy investment.

Research on Green and Low-Carbon Development Path of the Electric Power Industry

In the analogy where achieving the “carbon peaking and carbon neutrality” goals (the “dual carbon” goals) is compared to a battle, energy is the main battlefield, and electric power the main force. The low-carbon transformation path of the electric power industry exerts fundamental impact on progress towards carbon peaking and carbon neutrality of the whole society. Therefore, this paper first analyzes challenges and opportunities faced by the electric power industry to achieve the “dual carbon” goals; secondly, on the basis of deep low-carbon, zero-carbon and negative-carbon scenarios of the electric power industry, this paper quantifies and delves into the consumption structure of primary energy and final energy, as well as the future development positioning and trend of different categories of energy. Based on the research results, this paper proposes low-carbon transformation path of the electric power system at the stages of carbon peaking, deep low-carbon and carbon neutrality, and analyzes the trend of power supply cost changes in different scenarios. On this basis, a series of implementation key points and measures are proposed to adapt to green and low-carbon transformation of the electric power industry, covering areas such as coal-fired electric power development positioning, new energy development and utilization, diversified supply and demand, new energy industry chain, and power supply costs, and so forth.

Design of 98.8% Efficient 400-to-48-V $LLC$ Converter With Optimized Matrix Transformer and Matrix Inductor

Data centers have seen a rapid increase in power consumption in recent years, and the 48 V power architecture has gained popularity due to its efficiency. However, the cost of efficient power supplies remains challenging due to their complicated magnetic designs. The search for efficient and cost-effective power supplies continues. This paper focuses on the implementation of the DC-DC stage of the power supply unit for the 48 V data center bus architecture. In this paper, we present a design process for a high-efficiency, high-power-density 3 kW 400 V to 48 V LLC converter for use in data centers. Through optimization of the matrix transformer's geometry, turn number, and resonant frequency, we achieve superior efficiency and power density compared to state-of-the-art designs. To address challenges with the printed circuit board PCB-based inductors, we propose the use of a resonant matrix inductor, which reduces the number of stacked PCB layers, simplifies the winding implementation, and lowers the AC loss. By integrating the matrix inductor with the matrix transformer, we create a modular and scalable magnetic structure suitable for a wide range of voltages and currents. We also introduce EMI shielding for the matrix transformer with a full-bridge rectifier, resulting in an 18 dB reduction in common-mode noise. The prototype achieved a peak efficiency of 98.8% and a power density of 600 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> , demonstrating the effectiveness of the proposed design.

Intra-day optimal power flow considering flexible workload scheduling of IDCs

The online interactive workloads and offline batch computing services of Internet data centers (IDCs) have scheduling flexibility. Batch computing tasks with low latency sensitivity and priority can adjust the processing time and provide flexibility temporally. In contrast, interactive workloads with high latency sensitivity and priority can change the physical server for processing and provide flexibility spatially. Considering the change of power supply cost with time and space, the load flexibility of IDCs brought by Internet workload scheduling can be utilized to respond to the power system for more economical operation. To take full advantage of the flexibility of IDCs’ load demand, IDCs coordinated by an Internet service company (ISC) as a special controllable load with both temporal and spatial flexibility potential are considered. Instead of operating separately in normal optimal power flow (OPF) models, a two-stage interactive framework of the distribution system operator (DSO) and ISC is established. The operating state of the ISC is considered in OPF and is introduced as regularization terms into the objective function, thus fully exploiting its load flexibility. Some operation constraints are also added to guarantee the quality of service (QoS) of the ISC. The effectiveness of the model and the interactive framework are evaluated in a typical 33-bus medium-voltage distribution network. The results validate the further reduction of the power grid operation cost compared with the traditional OPF operation.

Electricity Tariff Design: A Survey

In a perfectly competitive market, electricity is priced at the Marginal Cost (MC); MC pricing guarantees economic efficiency (Gunatilake, et al. 2008). In other words, efficient electricity tariffs consider all power supply costs. To a great degree, it also accounts for capital investments for future expansion and up-gradation (Kojima, et al. 2014). In a free market, market forces of demand and supply pushed for MC recovery. In contrast, for a regulated market, the regulator sets the tariff according to the costs and reasonable return determined through the regulatory process. The regulator followed pre-determined guidelines, parameters, and standards set by the government; it may or may not be MC pricing. When a regulated tariff is set at a low level, it distorts the development/ functioning of the market at both the wholesale and retail levels. “If regulated end-user prices are not in line with wholesale market conditions, suppliers without significant low-cost generation capacity or equivalent long-term contracts will not be able to make competitive offers that will allow them to recover their costs. Consequently, with a limited number of suppliers, there will be no development of the wholesale markets. Liquidity will remain at a low level. As a result, neither the wholesale nor retail markets will be competitive” (Cited from Suzzoni, 2009, p. 5).

Subsidy removal, regional trade and CO2 mitigation in the electricity sector in the Middle East and North Africa region

This study analyzes the impacts on the power sector in the Middle East and North Africa region of three policies: removal of fuel subsidies, enhanced cross-border electricity trade, and a cap on carbon dioxide emissions. The analysis uses a power system planning model that minimizes the total electricity supply cost over 2018–2035 by satisfying specified technical, economic, environmental, and policy constraints. The study shows that the region would save between US$26.3 billion and US$27.5 billion, measured in 2018 prices, by removing subsidies to natural gas used for power generation. Cross-border electricity trade would save US$83.6 billion to US$90.9 billion. The two policies together would yield a reduction of 10 percent in cumulative power-sector CO2 emissions in the region, with a net cost savings of US$111 billion. If a carbon emission-constraining policy is considered to achieve the same level of emissions reduction, the power supply costs will increase by US$97 billion. The study also reveals that the removal of fossil fuel subsidies and expanded cross-border electricity trade significantly complement each other and also to achieve climate change mitigation targets in the MENA region.

Institutional repository infrastructure: a survey of Ghanaian public universities

PurposeGhanaian public universities have fully embraced the concept of open access. This is evident in the increasing numbers of institutional repositories (IRs) by universities in Ghana. However, to ensure the sustainability of these IRs, it is vital the current IR infrastructure is capable of responding to current and future demands. The purpose of this study is to investigate the sustainability of the current IR infrastructure of public universities in Ghana.Design/methodology/approachThe convergent parallel mixed methods design was adopted. A total of 830 respondents comprising IR managers, library staff (digitisation and e-resources units), postgraduate students, lecturers and university librarians from five public universities in Ghana were sampled for this study. A questionnaire and a semi-structured interview guide were the main instruments used for data collection.FindingsThe findings of this study revealed that the IR infrastructure of public universities in Ghana is robust and has the capacity to expand when the need arises. However, funding, cost of internet connectivity, personnel and erratic power supply were identified as major challenges confronting IRs in Ghana.Originality/valueThis study highlighted Ghana's existing IR infrastructure situation. This study is a significant contribution to the literature from West Africa because there is not much research on IR infrastructure from this part of the world.