Search Results (144)

Hydrogen-based Power Systems (H2PSs) are gaining accelerating momentum globally to reduce energy costs and dependency on fossil fuels. A H2PS typically comprises three main parts: hydrogen production, storage, and power generation, called packages. A review of the literature and Original Equipment Manufacturers (OEM) datasheets reveals that no single manufacturer supplies all H2PS components, posing significant challenges in system design, parts integration, and safety assurance. Additionally, both the literature and H2PS projects’ database highlight a gap in a systematic hydrogen equipment and auxiliary sub-systems technology selection process, and how this selection affects the overall H2PS Balance of Plant (BoP). This study addresses that gap by providing a guideline for available technology options and their impact on the H2PS-BoP. The analysis compares packages and auxiliary sub-system technologies to support informed engineering decisions regarding technology and equipment selection. The study finds that each package’s technology influences the selection criteria of the other packages and the associated BoP requirements. Furthermore, the choice of technologies across packages significantly affects overall system integrity and BoP. These interdependencies are illustrated using a cause-and-effect matrix. The study’s significance lies in establishing a structured guideline for engineering design and operations, enhancing the accuracy of feasibility studies, and accelerating the global implementation of H2PS. Full article

The integration of lithium-ion (Li-ion) battery energy storage systems (LiBESSs) with photovoltaic (PV) generation offers a promising solution for powering auxiliary services (ASs) in high-voltage power stations. This study conducts a systematic literature review (SLR) to evaluate the feasibility, benefits, and challenges of this integration. The proposed SLR complies with the PRISMA 2020 statement, and it is also registered on the international PROSPERO platform (ID 1073599). The selected methodology includes the following key steps: definition of the research questions; search strategy development; selection criteria of the studies; quality assessment; data extraction and synthesis; and discussion of the results. Through a comprehensive analysis of scientific publications from 2013 to 2024, trends, advancements, and research gaps are identified. The methodology follows a structured review framework, including data collection, selection criteria, and evaluation of technical feasibility. From 803 identified studies, 107 were eligible in accordance with the assessed inclusion criteria. Then, a custom study impact factor (SIF) framework selected 5 out of 107 studies as the most representative and assertive ones on the topics of this SLR. The findings indicate that Li-ion BESSs combined with PV systems enhance reliability, reduce reliance on conventional sources, and improve grid resilience, particularly in remote or constrained environments. The group of reviewed studies discuss optimization models and multi-objective strategies for system sizing and operation, along with practical case studies validating their effectiveness. Despite these advantages, challenges related to cost, regulatory frameworks, and performance variability remain. The study concludes that further experimental validations, pilot-scale implementations, and assessment of long-term economic impacts are necessary to accelerate the adoption of BESS-PV systems in high-voltage power substations. This study was funded by the R&D program of the Brazilian National Electric Energy Agency (ANEEL) via project number PD-07351-0001/2022. Full article

Since 1 January 2024, newly produced heavy-duty trailers are subject to the assessment of their performance regarding CO₂ and fuel consumption according to Implementing Regulation (EU) 2022/1362. The method is based on the already established approach for the CO₂ and energy consumption evaluation of trucks and buses, i.e., applying a combination of component testing and vehicle simulation using the software VECTO (Vehicle Energy Consumption calculation TOol). For the evaluation of trailers, generic conventional towing vehicles in combination with the specific CO₂ and fuel consumption-relevant properties of the trailer, such as mass, aerodynamics, rolling resistance etc., are simulated in the “VECTO Trailer” software. The corresponding results are used in the European HDV CO₂ standards with which manufacturers must comply to avoid penalty payments (2030: −10% for semitrailers and −7.5% for trailers compared with the baseline year 2025). Methodology and legislation are currently being extended to also cover the effects of electrified trailers (trailers with an electrified axle and/or electrically supplied auxiliaries) on CO₂, electrical energy consumption, and electric range extension (special use case in combination with a battery-electric towing vehicle). This publication gives an overview of the developed regulatory framework and methods to be implemented in a future extension of VECTO Trailer as well as a comparison of different e-trailer configurations and usage scenarios regarding their impact on CO₂, energy consumption, and electric range by applying the developed methods in a preliminary potential analysis. Results from this analysis indicate that e-trailers that use small batteries (5–50 kWh) to power electric refrigeration units achieve a CO₂ reduction of 5–10%, depending primarily on battery capacity. In contrast, e-trailers designed for propulsion support with larger batteries (50–500 kWh) and e-axle(s) (50–500 kW) demonstrate a reduction potential of up to 40%, largely determined by battery capacity and e-axle rating. Despite their reduction potential, market acceptance of e-trailers remains uncertain as the higher number of trailers compared with towing vehicles could lead to slow adoption, especially of the more expensive configurations. Full article

The long-standing need for a modern public transportation system in Lebanon, a developing country of the Middle East with an almost exclusive dependence on costly and polluting passenger cars, has become more pressing in recent years due to the worsening economic crisis and the onset of hyperinflation. This study investigates the potential reductions in energy use, emissions, and costs from the possible introduction of natural gas, hybrid, and battery-electric buses compared to traditional diesel buses in local real driving conditions. Four operating conditions were considered including severe congestion, peak, off-peak, and bus rapid transit (BRT) operation. Battery-electric buses are found to be the best performers in any traffic operation, conditional on having clean energy supply at the power plant and significant subsidy of bus purchase cost. Natural gas buses do not provide significant greenhouse gas emission savings compared to diesel buses but offer substantial reductions in the emission of all major pollutants harmful to human health. Results also show that accounting for additional energy consumption from the use of climate-control auxiliaries in hot and cold weather can significantly impact the performance of all bus technologies by up to 44.7% for electric buses on average. Performance of all considered bus technologies improves considerably in free-flowing traffic conditions, making BRT operation the most beneficial. A vehicle mix of diesel, natural gas, and hybrid bus technologies is found most feasible for the case of Lebanon and similar developing countries lacking necessary infrastructure for a near-term transition to battery-electric technology. Full article

Maritime transportation is crucial for global trade, yet it is a significant source of emissions. This study aims to enhance the operational efficiency and sustainability of container ports by accurately estimating energy needs. Analyzing data from 440 ships visiting a container port within a year, including parameters such as main engine (ME) power, auxiliary engine (AE) power, gross registered tonnage (GRT), twenty-foot equivalent unit (TEU), and hoteling time, regression analysis techniques were employed within MATLAB’s Regression Learner App. The model predicted future energy demands with an accuracy of 82%, providing a robust framework for energy management and infrastructure investment. The strategic planning based on these predictions supports sustainability goals and enhances energy supply reliability. The study highlights the dual benefit for port and ship owners in precise energy need assessments, enabling cost-effective energy management. This research offers valuable insights for stakeholders, paving the way for greener and more efficient port operations. Full article

This paper proposes a high-reliability power conversion system optimized for Urban Air Mobility (UAM) applications, which utilizes silicon carbide (SiC) chopper modules within a hybrid fuel cell and battery structure. The system features a redundant power configuration that employs both a main and an auxiliary battery to ensure continuous and stable power supply, even under emergency or fault conditions. By integrating SiC-based power converters, the proposed system achieves high efficiency, low switching losses, and enhanced thermal performance, which are crucial for the space- and weight-constrained environment of UAM platforms. Furthermore, a robust control strategy is implemented to enable smooth transitions between multiple power sources, maintaining operational stability and safety. System-level simulations were conducted using PowerSIM to validate the performance and reliability of the proposed architecture. The results demonstrate its effectiveness, making it a strong candidate for future UAM power systems requiring lightweight, efficient, and fault-tolerant power solutions. Full article

As our society becomes increasingly digitized, the demand for computing power provided by data centers continues to grow; consequently, operating costs are increasing exponentially. Data centers supply virtualized servers to customers, primarily in the form of lightweight containers. Since the number of containers to be allocated is fixed, they should be optimally placed on physical servers to minimize the number of required servers and reduce costs. However, current data center operations do not prioritize reducing the number of physical servers through optimized container placement. Instead, containers are distributed across existing servers primarily to maintain stability. Therefore, costs associated with servers, auxiliary facilities, and electricity consumption have increased. To address this issue, we propose an optimization method that ensures economic efficiency without compromising system stability. Specifically, we utilize deep reinforcement learning (DRL), which has been widely applied in various fields, to optimize container placement. Our approach outperforms traditional heuristic algorithms and offers the additional advantage of handling fixed-size inputs, enabling flexible operation regardless of the number of containers. Using DRL in container placement has further reduced the number of servers and operating costs while enhancing overall system flexibility. Full article

In order to improve the trading efficiency of virtual power plants (VPPs) participating in the market of multi-type auxiliary services under the gaming environment, an initial trading price setting method based on the information of VPPs’ response characteristics and real-time supply and demand changes is proposed to accelerate the convergence speed of the game. Firstly, a master–slave game trading model is established based on the reference auxiliary service pricing, which consists of a tariff coefficient and a basic tariff. Secondly, the tariff coefficient model is constructed based on response information, including response rate, quality, and reliability. Again, the basic tariff model is constructed based on the real-time supply and demand situation and the real-time grid tariff. Finally, the effectiveness of the proposed method in accelerating the convergence speed of the game is verified by analyzing 12 VPPs under the three auxiliary service scenarios of peaking, frequency regulation, and reserve. Full article

Depending on the type of fuels used by ships in maritime port operations, emissions may contribute more or less to the concentration of greenhouse gases in the atmosphere. The maneuvering of ships at maritime ports uses mainly auxiliary engines, resulting in a significant contribution to emissions. It is understandable that the energy transition in this sector brings benefits and is essential to sustainability, considering its economic and strategic importance. Among the measures established to ensure this transition is the onshore power supply and increased electrification in transportation operations. Maritime ports are not yet prepared for these adjustments, as their heterogeneity and contexts require further research, such as studying the impact of depth on energy consumption, terminal type, and others. The purpose of this paper is to quantify the reduction in greenhouse gas emissions achievable through the implementation of an onshore power supply at the Port of Sines, Portugal. Furthermore, it aims to identify the key factors influencing these adoptions to provide practical recommendations that can guide in advancing energy transition, reducing reliance on fuels, and fostering a sustainable future for the port industry. Full article

The automotive 12 V power net is undergoing significant transitions driven by increasing power demand, higher availability requirements, and the aim to reduce wiring harness complexity. These changes are prompting a transformation of the power net architecture. To understand how future power net topologies will influence component requirements, electrical simulations are essential. They help with analyzing the transient behavior of the future power net, such as under- and over-voltages, over-currents, and other harmful electrical phenomena. The accurate parametrization of simulation models is crucial in order to obtain reliable results. This study focuses on the wiring harness, specifically its resistance and inductance, as well as the loads within the low-voltage power net, including their power profiles and input capacities. The parameters for this study were derived from vehicle measurements in three selected battery electric vehicles from different segments and were enriched by virtual vehicle analyses. As a result, an extensive database of vehicle parameters was created and is presented in this paper, and it can be used for power net simulations. As a next step, the collected data can be utilized to predict the parameters of various configurations in a zonal architecture setup. Full article

In order to obtain acceptable efficiencies, hard-switching techniques and the converters that implement them must operate at relatively low frequencies (tens of kilohertz), which translate into converters of large size, weight, and volume, and therefore higher cost. To improve these characteristics, this work introduces a new transformerless MHz-range DC–DC converter that provides symmetrical bipolar outputs. The developed topology uses a single grounded switch, achieves soft switching (ZVS) over a wide load range, and does not require the use of floating or isolated controllers, reducing cost, size, and complexity. The output voltages are self-regulated to maintain the same value, ensuring balanced bipolar operation. A comprehensive analysis, design, sizing, simulation, implementation and testing are provided on a 150 W prototype operating at a switching frequency of 1 MHz, with step-up and step-down capability and implemented with GaN FET. The evaluated configuration shows an efficiency close to 90% and high power density, making it suitable for compact designs in a variety of applications requiring reliable power management and high efficiency such as lighting, electric vehicles, or auxiliary power supplies. Full article

The evolution of aircraft power systems has been driven by increasing electrical demands and advancements in aviation technology. Background: This study provides a comprehensive review and experimental validation of on-board electrical network development, analyzing power management strategies in both conventional and modern aircraft, including the Mi-24 helicopter, F-22 multirole aircraft, and Boeing 787 passenger airplane. Methods: The research categorizes aircraft electrical systems into three historical phases: pre-1960s with 28.5 V DC networks, up to 2000 with three-phase AC networks (3 × 115 V/200 V, 400 Hz), and post-2000 with 270 V DC networks derived from AC generators via transformer–rectifier units. Beyond theoretical analysis, this work introduces experimental findings on hybrid-electric aircraft power solutions, particularly evaluating the performance of the Modular Power System for Aircraft (MPSZE). The More Electric Aircraft (MEA) concept is analyzed as a key innovation, with a focus on energy efficiency, frequency stability, and ground power applications. The study investigates the integration of alternative energy sources, including photovoltaic-assisted power supplies and fuel-cell-based auxiliary systems, assessing their feasibility for aircraft system checks, engine startups, field navigation, communications, and radar operations. Results: Experimental results demonstrate that hybrid energy storage systems, incorporating lithium-ion batteries, fuel cells, and photovoltaic modules, can enhance MEA efficiency and operational resilience under real-world conditions. Conclusions: The findings underscore the importance of MEA technology in the future of sustainable aviation power solutions, highlighting both global and Polish research contributions, particularly from the Air Force Institute of Technology (ITWL). Full article

The implementation of photovoltaic and home storage systems in multi-family houses (MFHs) in Germany lags significantly behind their development in single-family houses. The Landlord-to-Tenant (L2T) power supply model is meant to reduce this gap, yet few projects have been implemented to date. In this model, the landlord must fulfill the tenants’ power demand through a combination of photovoltaic generation and storage and electricity from the grid, for which the landlord pays an auxiliary electricity price that greatly influences the financial viability of a project. Our contribution focuses on the impact of electricity price variations and recent policy changes on the financial viability of small-scale L2T concepts. We considered component investment costs, building sizes, photovoltaic yields, and future developments. Recent policy changes have improved the financial viability of L2T projects, increasing the maximal auxiliary electricity price for which an investment is viable by 13 ct/kWh for a four-party MFH. Minimal auxiliary electricity prices justifying the installation of home storage systems (HSSs) decreased by 9 ct/kWh from 2020 to 2023. Autarky rates are substantially different across the considered scenarios, with the autarky rate being defined as the percentage of consumption of self-generated energy relative to the total energy consumption. For a 22-party MFH the autarky rate decreases by 17% compared to a 4-party MFH. HSSs have the potential to increase autarky rates while maintaining the financial viability of L2T projects. Full article

This paper proposes a transient energy auxiliary supply circuit architecture based on resonant switched-capacitor principles, aimed at optimizing the system’s transient response to meet the growing power supply demands. This paper first introduces the relevant principles of resonant switched-capacitor converters. Based on this, a transient energy path topology based on resonant principles is designed to achieve bidirectional, fast, and low electromagnetic interference energy transmission. Corresponding system coordination control strategies and high-precision switch control based on delay lines are proposed for the designed circuit topology. A circuit model is built in SIMPLIS (V8.20a) software for system simulation, and a prototype is built based on FPGA to verify circuit functionality and performance. Experimental results demonstrate that the resonant energy auxiliary circuit can operate in conjunction with a six-phase Buck circuit prototype. Under test conditions of a 500 kHz operating frequency, 6.5 V input voltage, and 0.75 V output voltage, the overshoot voltage is reduced by more than 17% across the entire operating range. When the load steps from 200 A to 20 A, the overshoot voltage is reduced to only 85 mV, a decrease of 27.97%, while the recovery time is 28.8 µs, a reduction of 37.66%. These results confirm that the auxiliary circuit can significantly improve the system’s transient response under large load steps, meeting the design requirements. Full article

At present, the development of the global energy internet is occurring in depth and the construction of a distributed power supply is rapid, and the energy router (ER), as a key device for integrating energy flow and information flow, has important application value in microgrids. In this paper, a multi-port energy router based on a 710 V DC bus is designed and developed with a modular structure design, including core components such as a total controller, a power converter, a hybrid energy storage system, and an auxiliary power supply. Flexible access and the management of multiple-voltage-level ports (690 V AC, 380 V AC, 220 V DC, and 24 V DC) are realized through rational topology design. The test results of the device show that the system performance indexes meet the design requirements. The operation is stable and reliable, displaying strong practical engineering value, and at the same time provides a technical solution that can be borrowed for other special scenarios such as the microgrid system. Full article