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As a mainstream power storage and supply device, batteries are continuously upgraded. The microfluidic fuel cell has great development potential, and the paper-based microfluidic fuel cell is the latest achievement of its lightweight, which can be applied in the field of medical and biological detection. In this work, the cell models with various folding forms and unconventional absorption pads are creatively constructed, then the influence mechanism on cell performance is revealed by numerical simulation. Both transient and steady-state simulation methods are employed to monitor the whole process of paper-based microfluidic fuel cell. Conclusions show that the cell performance decreases with the increase of folding angle, the peak power density is as low as 1.71 mW/cm2, and the corresponding fuel utilization is only 2.73%. The changes in the absorbent pad shapes have little improvement on cell performance, thus the most direct way is increasing the absorbent pad volume. Moreover, materials with better water absorption capacity can increase the maximum current density to 28.70 mA/cm2, and the appropriate increase of operating temperature can also increase the peak power density to 2.36 mW/cm2, but the effect on the cell is significantly weakened if the temperature exceeds a certain limit. [ABSTRACT FROM AUTHOR]

Gas diffusion layer (GDL), as an important transmission component of gas, electricity and liquid, is usually composed of carbon paper, which needs hydrophobic treatment before it is applied in fuel cell. In the paper, ultrasonic dispersion technique is added to the traditional method of preparing hydrophobic carbon paper, and the effect of ultrasonic dispersion on the PTFE load in hydrophobic carbon paper is studied. The theoretical study shows that the ultrasonic dispersion increases the movement of the liquid, thus improving the diffusion performance of the liquid molecules. The experimental results show that compared with the hydrophobic performance of the original carbon paper, the hydrophobic carbon paper prepared by ultrasonic method improves the hydrophobic performance by 13.24%. However, there is no obvious relationship between the PTFE content of the carbon paper treated by ultrasonic dispersion and the hydrophobicity of the carbon paper surface. In addition, ultrasonic dispersion also has a great influence on the gas permeability of hydrophobic treated carbon paper, but the effect on the surface conductivity of carbon paper is not obvious. The results can provide a guidance for the preparation of hydrophobic carbon paper for fuel cells. • Properties of hydrophobic carbon paper prepared by ultrasonic method are studied. • The Carbon paper prepared by ultrasonic method has better gas permeability. • Ultrasonic method can significantly improve the content of PTFE in carbon paper. • Ultrasonic method can improve the uniformity of PTFE material distribution. [ABSTRACT FROM AUTHOR]

As a rising star, the fuel cell will be applied very broadly. However, when the fuel cell works at a high current, too much water yield and the redundancy water block the air or oxygen enter the fuel cell, then the power reduces sharply. The gas diffusion layer (GDL) in the fuel cell is the critical component to transfer water and gas. A novel GDL was prepared in this paper to improve transferability. The new GDL consists of one carbon paper and two microporous layers. The microporous layer close to carbon paper is modified by pore-former CaCO 3. The total thickness of the new GDL is 270 μm; then, the samples were pressed to 220, 240, and 260 μm by rolling, respectively. The electrochemical impedance spectroscopy tests at a large current (2.5 A/cm2) show that the fuel cell with 240 μm GDL has relatively small transmission impedance regardless of high or low humidity. The results show that the new GDL can significantly improve the water transferability of the proton exchange membrane fuel cell. [ABSTRACT FROM AUTHOR]

Constant electrode (CE) operation of a unitized regenerative fuel cell (URFC) facilitates the optimization of each electrode. In this work, bipolar plates (BPPs) with different flow fields (FFs) are assessed, and a graphite BPP is compared with a titanium BPP in the cathode. Platinum coated titanium felt and carbon cloth and paper gas diffusion layers (GDLs) are tested in the cathode. The carbon BPP and GDLs operated with higher ohmic resistance than the titanium alternatives. However, the titanium GDL caused flooding in FC mode. Carbon GDLs can be applied in the cathode, where carbon paper operated with higher performance than carbon cloth. Titanium GDL is still required in the anode to resist the corrosive environment. A double-serpentine FF in the cathode and a parallel design in the anode were applied. Optimization of the URFC operating conditions under FC mode provided the best results at 80 °C, 2 bar abs , with saturated air and dry hydrogen and stoichiometry ratios of 2 and 8. This resulted in a round-trip efficiency of 56% at 0.1 A cm−2, 48% at 0.3 A cm−2 and 22% at 1 A cm−2. In comparison, 56%, 52% and 37% were obtained with a discrete regenerative fuel cell (DRFC). [ABSTRACT FROM AUTHOR]

Membraneless microfluidic fuel cell (MMFC) has potential application prospects in micro-devices due to the characteristics of considerable output performance, superior cleanliness and easy miniaturization. Whereas, the performance of MMFC is restricted by the mass transfer of two-phase flow, which manifests as the inefficiency transportation in liquid phase and obstruction of gas phase. This paper proposes a novel sinusoidal corrugated channel (SCC) for MMFC though developing a three-dimensional two-phase model by coupling the multi-physics field to improve the cell performance in mass transfer, and further studies the two-phase flow characteristics of geometric parameters of SCC, including the amplitude A and angular frequency ω. Based on the optimal configuration in A of 0.5 mm and ω of 3 rad s−1, compared with the conventional straight channel, the increase ratios of maximum current density, power density, fuel utilization are 13.69%, 8.39% and 13.72%, respectively. Additionally, the gas volume fraction at the maximum power density decreases by 12.62%. This paper provides new insights and theoretical foundations for the study of MMFC flow field configurations, and furnishes references for the mass transfer intensification. [ABSTRACT FROM AUTHOR]

In this paper, a three inputs six-phase Interleaved Boost Converter (IBC) is proposed and designed for Fuel Cell (FC) systems, where the different Polymer Electrolyte Membrane Fuel Cells (PEMFC) systems are employed to validate. Considering that the selected converter is composed of three two-phase IBCs connecting in parallel, it shows many superiorities in topology, such as simple structure, high scalability/flexibility, easy maintenance and good fault-tolerant ability. The whole design process containing the selection of phase numbers, parameters design of the converter's components and steady-state operations analysis is focused in this paper. To further validate the correctness of the designed converter, a test bench is established based on dSPACE1104 , where the issue of the implementation of six-PWM signals from dSPACE1104 is analyzed and a feasible solution is proposed. Last, experimental results are shown by performing the load disturbance rejection, the variable reference voltage and the PEMFC system's failure based on the designed Double-Loop Super-Twisting Sliding Mode (DL-STSM) controller. • Three inputs six-phase interleaved boost converter is designed for fuel cell systems. • The designed converter shows high scalability and good fault-tolerant ability. • A solution is proposed to address the achievement of six-PWM signals in dSPACE1104. • Experimental verification of the designed converter with different fuel cell systems. • Load disturbance rejection, variable reference voltage and FC failure are validated. [ABSTRACT FROM AUTHOR]

The global energy sector is currently undergoing a fundamental transformation as it shifts away from fossil fuels towards renewable energy sources. Green hydrogen is one of the most promising energy carriers of the future in the worldwide effort to reduce the carbon footprint of energy systems. The advancement and uptake of green hydrogen technologies depend on various technological, environmental, and economic factors. In this paper, a comprehensive review of recent studies in green hydrogen energy systems (GHES) is conducted, highlighting technoeconomic aspects from the component to the technology and broader system level. Firstly, the technological principles and recent progress of different green hydrogen generation, storage, and utilization technologies are summarized. Subsequently, an in-depth analysis of various technoeconomic modeling and experimental activities focused on integrated GHES is undertaken. By examining applications in the stationary and transport sectors, this review paper offers an assessment of the current state-of-the-art in terms of development and integration options. The technical challenges, key factors, and future research directions of green hydrogen technologies and systems are outlined, demonstrating that an effective, intelligent, and innovative integration of GHES with other technologies will encourage a more efficient use of resources and enhanced energy system flexibility, resilience, and energy security. • Characteristics, components and configurations of green hydrogen systems are presented. • Technoeconomic studies are collected in tabulated form and exhaustively analyzed. • State-of-the-art applications in stationary and transport sectors are discussed. • A critical review is provided to assess green hydrogen economic viability potential. • Challenges and prospects are evaluated, and future research directions are suggested. [ABSTRACT FROM AUTHOR]

Hydrogen fueling stations (HFSs) with onsite hydrogen production systems, which are usually composed of electrolyzers, hydrogen storage tanks and fuel cells, not only supply hydrogen for hydrogen-powered vehicles but also serve as a dispatchable technology that can bid in electricity markets. Except participating in energy market, joining in reserve market can compensate the cost in energy market and increase the total revenue of HFS. This paper proposes a multi-stage stochastic programming model to find the optimal offering strategy of the HFS in energy, reserve markets taking into account a series of uncertainties: day-ahead price, secondary reserve price, system imbalance price and hydrogen demand. Nonanticipativity constraints are employed to guarantee the decisions are made according to the realized uncertainty information up to the present stage. Compared with traditional stochastic programming model, the proposed model adequately considers the sequential bidding decisions with the gradual revealing of the uncertainty over time. Numerical experiments based on one case study indicate that the participation of reserve market greatly increase the revenue of HFS. In addition, the proposed multi-stage stochastic programming model is effective in characterizing the sequential decision. • This paper proposes a multi-stage stochastic programming model. • To find the optimal offering strategy of the HFS in energy, reserve markets. • A series of uncertainties such as day-ahead price, and hydrogen demand are considered. • Nonanticipativity constraints are employed to guarantee the sequential decisions. [ABSTRACT FROM AUTHOR]

System risks caused by volatility spillover would possibly threaten the stability of financial markets. Effective control of volatility spillover is conducive to prevent of financial system risks. Therefore, this paper studies volatility spillover in the main renewable energy markets from 2010 to 2019 and analyzes how risks spread in hope of finding effective management to reduce financial system risks. For this purpose, this paper identifies the volatility spillover effect from a multidimensional perspective by using the BEKK model and reveals the risk spread path by using the multidimensional analysis method. Further, the risk spread relationships among the renewable energy markets are comprehensively analyzed. The main findings of the paper are: (1) The volatility spillover in the renewable energy markets tends to exist in the high dimensions. (2) In the renewable energy market system, the volatility spillover relationships involving multiple markets are more complicated than those between two markets. (3) The fuel cell energy market and solar energy markets occupy a significant position in the path of risk spread which should be paid more attention by policymakers to prevent financial system risks. [ABSTRACT FROM AUTHOR]

This paper proposes an energy management system (EMS) for nanogrids to balance the power supply and forecasted demand in consideration of forecasting errors arising from high instantaneous demand. The proposed EMS employs a power-balancing optimization process for forecasted demand and a reference power modulation strategy for forecasting errors. This power-balancing optimization utilizes nanogrid sources, such as photovoltaics, fuel cells, and batteries, to meet forecasted demand and a supercapacitor charging process to overcome issues with a low energy density. The proposed reference power modulation strategy is utilized to allocate power from a hybrid energy storage system consisting of a battery and supercapacitor in order to compensate for forecasting errors. In addition, this proposed strategy considers battery and supercapacitor constraints such as the power changing rate and total power limitations. The power-balancing optimization process also operates at faster sampling rate than the reference power modulation process in order to improve the computational efficiency. The performance of the proposed EMS is evaluated using real data obtained from the Korea Electric Power Exchange. • This paper proposes a cascaded structure energy management system (EMS) for nanogrid to balance power for both forecasted demand and forecast errors including high instantaneous demand. • The proposed EMS comprises a power balancing optimization process for forecasted demand and reference power modulation strategy for the forecast errors. The power balancing optimization utilizes nanogrid sources, such as PV, fuel cell, and battery, to meet forecasted demand as well as a supercapacitor charging process for addressing low energy density characteristics. • The proposed reference power modulation strategy is utilized to allocate power from the HESS comprising a battery and supercapacitor, in order to compensate forecast errors. In addition, this proposed strategy is performed considering battery and supercapacitor constraints such as their power changing rate, total power limitation. [ABSTRACT FROM AUTHOR]

Apart from electricity, high-temperature proton exchange membrane fuel cell also produces a lot of waste heat, leading to energy wasting. Harvesting the waste heat for additional cooling production may further improve the commercial competitiveness. In this paper, we propose a novel combined system model that integrates high-temperature proton exchange fuel cell with heat-driven elastocaloric cooling system. Considering different sources of irreversible effects, mathematical formulas of performance indicators for each subsystem and combined system are specified. In addition, energetic and exergetic analyses are conducted to assess the potentiality of elastocaloric cooling system as a waste heat recovery candidate. The maximum power output density of the combined system can be boosted by 9.18% in comparison with that of a single fuel cell. The basic performance features and optimum criteria of the proposed system performance are expounded. Extensive sensitivity analyses and calculation examples have been conducted to check the dependance of the proposed combined system performance on some important design variables and operation conditions. [ABSTRACT FROM AUTHOR]

With the rapid development of new energy vehicles, designing an excellent DC/DC converter to realize the efficient interaction of hydrogen and solar energy is crucial for the power regulation of hybrid electric vehicles driven by both solar energy and hydrogen fuel cells. In this paper, a high-performance multiphase DC/DC boost converter which can be shared by the solar generation system and hydrogen fuel cell in a hybrid vehicle is proposed to achieve light weight, low input current ripple, fast response, minimal power loss, high compactness and high redundancy. It is equipped with a novel high power density active snubber cell that realizes soft-switching of all semiconductor devices, and itself is also characterized by N-phase expansion, the low voltage and current stresses and the short operation time in each switching period. Thus, choosing low voltage and current rated components to achieve high efficiency, high power density and low cost is feasible. Operating principle, design procedure, control strategy and power loss analysis of the proposed converter are given in detail. The performance is evaluated on a 2-phase DC/DC boost converter prototype. The peak conversion efficiency reaches 98.8 % and the experimental results agreed well with the theoretical predictions. [ABSTRACT FROM AUTHOR]

The application of green energy technologies to supply berthed ships in ports with the necessary power instead of using their diesel generators is considered an initiative towards sustainability and climate change mitigation. Therefore, the current paper investigates the implementation of solar panels, offshore wind turbines, and hydrogen fuel cell systems as green technologies to supply the berthed ships with power in three Egyptian ports. The power requirements are determined by analyzing the annual ship traffic data and estimating the energy demand for each ship type. As a relevant result, the annual energy demand for ships berthed in Alexandria, Damietta, and Safaga ports is about 44.2 × 103 MWh, 22 × 103 MWh, and 5.6 × 103 MWh, respectively. The analysis results reveal a potential annual carbon dioxide reduction of 31.7 k-tons, 15.7 k-tons, and 4.2 k-tons in Alexandria, Damietta, and Safaga ports, respectively. From an economic perspective, the levelized cost of energy (LCOE) of solar panels is estimated to be 80.7–90.1 $/MWh, while hydrogen fuel cells have a cost of 166.8–172 $/MWh. On the other hand, LCOE in the case of wind turbines is estimated to be 140.8 $/MWh for Alexandria ports, 178.3 $/MWh for Damietta port, and 103.9 $/MWh for Safaga port. [ABSTRACT FROM AUTHOR]

Ammonia as an energy storage medium is a promising set of technologies for peak shaving due to its carbon-free nature and mature mass production and distribution technologies. In this paper, ammonia energy storage (AES) systems are reviewed and compared with several other energy storage techniques. It is shown that once optimized for commercial use, AES systems have the potential for cost-effectiveness and efficiency. Its independence of topographic or climatic resource availability makes it an ideal option for many locales that has no provisions for pumped-hydro storage or with too harsh a climate for electrochemical batteries to survive. The range of applications for AES systems covers common utility-scale storage and includes electric vehicles applications. In this review, the viability of ammonia as a hydrogen carrier is discussed in detail, especially as a thermochemical energy storage media, and as a fuel for fuel cells and internal combustion engines. The health and safety impacts of ammonia are also highlighted and discussed. • Ammonia offers an attractive energy storage system due to its well-established infrastructure. • Ammonia showed great promise as a viable hydrogen fuel carrier. • Energy can be stored in the chemical bonds of ammonia through the endothermic ammonia synthesis reaction. • Ammonia can be used as a fuel in fuel cells and internal combustion engines. • The challenges as well as future research directions ammonia storage systems are highlighted. [ABSTRACT FROM AUTHOR]

Metallic bipolar plates (BPs) are extensively applied in fuel cell stacks to achieve an extremely high power density, and are thus suitable for vehicle applications. Corrosion of metallic BPs and contamination on membrane electrode assemblies have become key issues. Automotive operating conditions significantly accelerate BP corrosion and surface destruction. Accelerated stress tests, simulating dynamic load and startup-shutdown, are conducted to reveal the operation-induced corrosion mechanisms of typical SS316L BPs. The dynamic potential in the normal range (0.6–0.95 V) accelerates the local breakdown and damage of the passivation layer, leaving pits rich in Cr-species. The abundant Cr-species in the pits prevents further dissolution of Fe-speices and relieves local corrosion. The startup-shutdown condition extends the cathode potential to the trans -passivation and secondary passivation regions. Startup-shutdown drives BP into complex evolution stages of corrosion and passivation. Frequent alternation of potentials between passivation and trans -passivation regions accelerates alternant dissolution of outer Fe-species and Cr-species, thus causing global destruction represented by flocculent microstructure and interlinked pits. The ultrahigh cathode potential in startup-shutdown may induce an obvious surface film via strong secondary passivation. This paper can further guide the test protocols to evaluate the durability of metallic BP and condition optimization to avoid extreme corrosion damage. [ABSTRACT FROM AUTHOR]

Abstract Comprehensive computational modeling based on a full statistical approach is performed to investigate the heterogeneous multi-transport characteristics in the gas diffusion layers of fuel cells. For the purposes, a series of carbon paper gas diffusion layers are randomly generated at a 95% confidence level to reflect the heterogeneous microstructures. A representative element volume is determined based on the relative porosity gradient errors to minimize the uncertainty in the statistical analysis. Subsequently, a single-phase three-dimensional lattice Boltzmann method is applied to obtain the velocity distribution throughout the porous layers, enabling to calculate the average tortuosity. The effective mass diffusivity in the diffusion layers is then derived from the tortuosity factor. Additionally, three directional permeabilities are derived from the pressure gradient to account for the anisotropic characteristics of the porous diffusion layers. The relationship between the permeability and porosity is found to match the modified Kozeny–Carman equations. Further, a path-finding algorithm based on the percolation theory is developed to simulate electron and thermal conduction along the carbon fibers in the in-plane and through-plane directions. The present model can be utilized to investigate the heterogeneous transport characteristics of fibrous porous diffusion media for various electrochemical systems. Highlights • 3D GDL microstructures are generated randomly with nonoverlapping carbon fibers. • A stochastic approach over REV is established to minimize numerical uncertainty. • Typical Bruggeman correlation is not applicable to inhomogeneous carbon paper GDLs. • Effective mass diffusivity is modified due to a lower tortuosity from LBM results. • In-plane electrical and thermal conductances are predicted to be relatively higher. [ABSTRACT FROM AUTHOR]

Converting waste biomass to fuel and coupling it with solid oxide fuel cell to generate electricity cheaply and efficiently is what researchers are pursuing to achieve carbon neutrality. Therefore, a novel scheme of biosyngas-fueled solid oxide fuel cell power generation integrated with carbon capture is proposed in this paper, fully converting woody biomass into syngas. Based on the mathematical modelling, this system is evaluated by multiple evaluation criterion, including thermodynamic, economic and environmental perspectives. The correctness and accuracy of the proposed model are validated against the published literature. The studies on the key operating parameters show that increasing the gasifying temperature can markedly improve the quality of syngas, while the improvement of steam to biomass ratio is not evident, and the conversion ratio of water gas shift reactor is crucial for carbon capture. Moreover, low current density and high fuel utilization ratio are preferable to the high-efficiency power generation of solid oxide fuel cell. After multi-objective optimization, the CO 2 emission ratio and energy efficiency achieve 0.285 t/MWh (is the lowest among various schemes) and 52%, which proves that the proposed scheme is a highly-efficient and eco-friendly power generation system. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic and static characterization of commercial metal hydride tanks is developed based on black box modelling. The objective is to determine the thermodynamic parameters of the hydride, such as enthalpy and entropy, and then to perform an energy management of this hydrogen storage system coupled to a fuel cell generator. Therefore, for this study, a specific test bench was developed around two hydride tanks. The hydrogen temperature and pressure were measured as a function of time and used to evaluate the thermal energy produced and consumed, as well as the amount of hydrogen, stored and released, during the absorption and desorption process respectively. The analysis of the results allowed the determination of a number of parameters such as the maximum reversible hydrogen storage capacity, which was 100 [g] for each tank with a relative capacity of 0.8 [%], the equilibrium pressure between 1 and 4 [bar] for both processes (absorption/desorption) as well as the evaluation of the hysteresis. The black-box approach makes this characterization method suitable for any solid-state hydrogen storage system, regardless of metal hydride type, geometrical shape, and tank size. [ABSTRACT FROM AUTHOR]

Microfluidic fuel cell is an underlying clean power in the future, it is regarded as a new developing direction of power source in portable electronic device with its considerable power output and cleanness, but some challenges hinder it in putting into practical application. Vibration and two-phase flow are the two non-negligible factors which have an impact on the liquid-feed microfluidic fuel cell, but the internal mechanism is not clear, a mechanism study shall be conducted to analyse the coupling effect on cell characteristic. A biphasic model, in this paper, is established with the integration of vibration effect and bubble dynamics theory. Results illustrate that the increases of vibration intensity and frequency cause the CO 2 distortion, and postpone the bubble separation and elimination. The anode activation reaction site is therefore reduced, resulting in the cell performance degeneration. The increased feed liquid flow rates accelerate the bubble behavior and improve the current and power outputs, but the system efficiency is sacrificed. Increasing contact angle is a valid approach to the bubble separation and performance improvement. This study provides a theoretical understanding for the prospective optimisation design via the mechanism study and breaks a new path for novel power source investigation. [Display omitted] [ABSTRACT FROM AUTHOR]

Oxygen side flow channel structures have significant influence on the dynamic response of relevant parameters in operation mode switching procedures of a unitized regenerative fuel cell. In this paper, an unsteady, non-isothermal, two-phase, two-dimensional unitized regenerative fuel cell model is established to study the dynamic response of two-phase species concentration distributions, current density distributions etc. when the cell mode swiches from the fuel cell mode to the electrolyzer when using orientational flow channel at the oxygen side. The influence of eight oxygen-side channels on the mode switching process is compared. Results show that the required time for each parameter reaching the stable state in the fuel cell mode is longer than the dynamic response time after switching to electrolytic cell mode when using orientational flow channels. In addition, different flow channel structures at the oxygen-side affect the time requirement for stabilizing each parameter during mode switching, while they do not change the characteristics of the stable state mode. • An un-steady state model of URFCs with orientational channels is developed. • Dynamic response of operation parameters vary under channel structure effects. • Decreasing channel depth percentage enhances cell performance. • Orientational channels facilitate stabilizing operation parameters of URFCs. [ABSTRACT FROM AUTHOR]

The startup-shutdown behavior of the gas foil bearings-rotor system is vital for proton exchange membrane fuel cells due to the inherently frequent start-stop of hydrogen fuel cell vehicles, which significantly affects the sustainable power generation and efficiency of the fuel cells. In this paper, the effects of three systematic factors including bump foil structure, nominal clearance, and coating on the dynamic response of the bearings-rotor system are first investigated based on startup-shutdown experiments. The mathematical model considering both gas film and thermo-hydrodynamic characteristics is presented to investigate the startup-shutdown behavior further. The influencing mechanisms of the factors on performance are analyzed. The energetic results demonstrate that the bearing structure parameters have a significant influence on the startup-shutdown performance and energy consumption. Considering optimal startup-shutdown performance, a better bearings-rotor system is proposed. Compared to the average values in all cases, the take-off speed, temperature rise, and average energy consumption of the system are decreased by 51.3%, 16.2%, and 60.7%, respectively. This indicates that the startup-shutdown improvement of the bearing-rotor system has great significance for enhancing the energy efficiency of the fuel cell. [ABSTRACT FROM AUTHOR]

Hydrogen fuel has received widespread attention as one of the critical solutions to global energy issues. The popularization of hydrogen fuel cell vehicles (HFCV) requires the deep integration of transportation and energy fields. Considering the complementarity of wind and PV power in remote areas, this paper proposes a planning model of an expressway hydrogen refueling station, including a hydrogen production system (HPS) powered by a wind-PV system and several hydrogen refueling systems (HRSs). The interaction and operation constraints of hydrogen production, storage, delivery, and demand are employed to complete hydrogen supply chain integration in the deterministic planning model. The spatiotemporal distribution of refueling demand at each HRS is obtained by Monte Carlo Simulation. Furthermore, we consider the impact of uncertainty related to renewable energy generation and refueling demand on planning and depict them by ambiguity sets based on Kullback Leibler divergence. The planning problem is transformed into a data-driven distributionally robust model and solved by Value-at-Risk and sample average approximation method. Results indicate that 1) The proposed model can simultaneously collaborate with the segments of the hydrogen supply chain. 2) The proposed method balances the planning reliability and economic efficiency and enhances solution robustness. [ABSTRACT FROM AUTHOR]

In this paper, a novel model of electric-hydrogen integrated charging station (ICS) is proposed, which is composed of battery swapping station (BSS) and hydrogen station (HS). The BSS model, which mainly includes user adaptive response model, battery allocation and scheduling strategy, is established to realize the reasonable management and allocation of batteries. The HS model mainly includes hydrogen production module, hydrogen storage module, hydrogen charging module, fuel cell module and hydrogen scheduling strategy to optimize scheduling from hydrogen production to use. In addition, the BSS can provide energy for HS, and both BSS and HS can feed back the stored energy to the power system during peak load, which is beneficial to the stable operation of the power system. Simulation shows the rationality and correctness of the proposed optimization model. The proposed model and optimization strategy can improve the flexibility and economy of ICS, and help the power system to cut peak and fill valley. [Display omitted] • A model of electric-hydrogen integrated charging station is proposed. • The battery swapping station and hydrogen station are jointly optimized. • The energy transfer of the integrated charging station is more flexible. • The integrated charging station can provide auxiliary services for the power grid. [ABSTRACT FROM AUTHOR]

In this study, the optimization of a multisource hybrid photovoltaic (PV)/Wind/Diesel/Fuel cell (FC) system is performed to meet three realistic loads demand for heavy, medium and small activities observed at Figuil, Cameroon. This paper also examines and compares the techno-economic viability of an off-grid hybrid PV/Wind/Diesel/FC, PV/Diesel/FC and Wind/Diesel/FC systems in terms of net present cost (NPC), cost of energy (COE) and environmental emissions. The effectiveness of different evolutionary algorithms employed in the designing problem of the various hybrid systems is also investigated. The results revealed that, for maximum loss of power supply probability (LPSP) of 5% and minimum renewable energy fraction of 85%, the PV/Wind/Diesel/FC system is economically the best choice for supplying the three types of non-domestic loads demand with corresponding NPC, COE and LPSP values of 159319.4$, 1.087$/kWh and 0.0397 for heavy activity; 150185.8$, 1.753$/kWh and 0.0411 for medium activity; and 144588.0$, 2.384$/kWh and 0.0288 for small activity, respectively. The results also demonstrated that, in terms of pollution emissions minimization, the PV/Wind/Diesel/FC configuration is a preferable option, with an overall yearly CO 2 emissions of 2946.1 kg, 2043.6 kg and 1504.2 kg corresponding to an annual total fuel consumption of 1115.9L, 774.1L and 569.8L for heavy, medium and small activities, respectively. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop an accurate model for the polymer electrolyte membrane fuel cell (PEMFC), that can precisely mimic and simulate the electrical characteristics of actual PEMFC stacks at different operating conditions. Models of PEMFC are empirical, multi-variables and have many non-linear terms that should be estimated accurately to ensure appropriate modeling. In this paper, a novel application based-on a nature-inspired metaheuristic optimization algorithm namely, the grey wolf optimizer (GWO) to identify PEMFC model parameters is addressed. The GWO relies on the principles of metaheuristic techniques, exploration and exploitation phases, in order to avoid sticking in local optima and getting better solution. The proposed GWO-based method is tested on five commercial PEMFCs. Many investigations and performance tests are made to prove the effectiveness of the algorithm to simulate the electrical behavior of those commercial PEMFC stacks based-on experimental data. In addition, parametric and non-parametric statistical tests are in place to assess the effectiveness of the proposed method. For more validation, PEMFC model based-on GWO is compared with other challenging algorithms published in literature, and very competitive results are reported. [ABSTRACT FROM AUTHOR]

The paper focuses on fabricating a white cement brick fuel cell (WC–BFC) using agricultural waste rice husk ash (RHA) for sustainable power generation. The samples from each material with three different compositions 0, 2, and 12% of RHA were analysed. First with (RHA + sand) and (RHA + sand + cement) for commercial brick technology. This study aims to replace the present ordinary old concrete brick with WC-BFC technology in the market. Steel is an essential material used in concrete for longs decades due to its strength and stability. Therefore, the brick cost depends on the type of electrode used for brick fabrication. However, Ammonium chloride 0.3 g/ml was used as fuel with regular intervals of time for WC-BFC. Where steel/graphite electrodes generate a higher power density of 2008.93 mW/m2 with 12% RHA concentration and later for long life electrodes, Graphite/Graphite is also optimised to see the effect on the power. These bricks themselves generate massive free power from their own. The proposed technology is eco-friendly, inexpensive, sustainable, and compatible with generating renewable energy for vast brick commercial applications. On one side work as a regular concrete brick, and another side free power supply. This technology itself is clean, safe, and sustainable. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents the degradation prognosis of Proton Exchange Membrane Fuel Cell (PEMFC) operated under several conditions based on the combination of two types of data: data from postal fuel cell hybrid electric vehicles equipped with PEMFC and carrying out their postal delivery missions and PEMFC degradation data from laboratory. The prognosis is based on wavelet analysis and Nonlinear Autoregressive Exogenous Neural Network (NARX). The influences of historical state, operating conditions (load current, relative humidity, temperature, and hydrogen pressure), global degradation trend, and recovery phenomena on the degradation prognosis of PEMFC are considered. Firstly, the raw voltage degraded waveform of PEMFC is decomposed into multiple sub-waveforms by the wavelet analysis. Then, the degradation prognosis of each sub-waveform is made by NARX. Finally, the overall degradation prognosis of PEMFC is gotten by combing the degradation prognosis of each sub-waveform. Experimental results have shown that the novel prognosis method which exploits the two types of data results in a reliable model that covers PEMFC degradation over a wide range of operating conditions. The proposed prognosis method not only can make an accurate degradation prognosis of PEMFC with less learning data but also can use directly the raw experimental data with large fluctuation. • A degradation prognosis method of PEMFC under different applications is proposed. • Proposed method makes degradation prediction of PEMFC based raw experimental data. • Nonlinear autoregressive exogenous neural network combines with wavelet analysis. • The historical state, operating conditions, and recovery phenomena are considered. • Method is validated by 3 durability tests of PEMFC under different applications. [ABSTRACT FROM AUTHOR]

This paper examines the potential of solar-hydrogen hybrid renewable energy systems as a solution for off-grid applications in areas with heavy rainfall. This study highlights the immense potential of renewable mini grids as a solution to Africa's energy access challenges helping to achieve the sustainable development goal SDG 7. Associated to Photovoltaic primary source (PV), the combination of Lithium-Ion batteries and Alkaline hydrogen system emerges as an effective approach for ensuring uninterrupted electricity supply, especially in rainy seasons. This solution mitigates the need for Diesel Generator, offers protection against fluctuations in diesel fuel prices, and concurrently results in significant reductions in CO2 emissions while optimizing the utilization of PV energy. The uniqueness of this approach is the use of hydrogen as a backup solution. Hydrogen, generated through electrolysis, serves as a reliable energy reservoir during periods of low renewable energy production. This capability enhances the mini-grid's resilience, guaranteeing continuous electricity feeding to off grid critical facilities where power outages can have significant consequences. However, the exclusive use of hydrogen in conjunction with PV energy requires further cost reductions for broader competitiveness, especially concerning Solid Oxide Cell (SoC) electrolyzers. Furthermore, fuel cells, across all hydrogen technologies explored, require continuous development to improve their cost-efficiency and streamline their widespread adoption. Nevertheless, the improvement that can be made to reduce the Hydrogen system CAPEX and enhancing its efficiency would make green hydrogen as a competitive and reliable primary storage solution. [ABSTRACT FROM AUTHOR]

This paper examines the potential of solar-hydrogen hybrid renewable energy systems as a solution for off-grid applications in areas with heavy rainfall. This study highlights the immense potential of renewable mini grids as a solution to Africa's energy access challenges helping to achieve the sustainable development goal SDG 7. Associated to Photovoltaic primary source (PV), the combination of Lithium-Ion batteries and Alkaline hydrogen system emerges as an effective approach for ensuring uninterrupted electricity supply, especially in rainy seasons. This solution mitigates the need for Diesel Generator, offers protection against fluctuations in diesel fuel prices, and concurrently results in significant reductions in CO2 emissions while optimizing the utilization of PV energy. The uniqueness of this approach is the use of hydrogen as a backup solution. Hydrogen, generated through electrolysis, serves as a reliable energy reservoir during periods of low renewable energy production. This capability enhances the mini-grid's resilience, guaranteeing continuous electricity feeding to off grid critical facilities where power outages can have significant consequences. However, the exclusive use of hydrogen in conjunction with PV energy requires further cost reductions for broader competitiveness, especially concerning Solid Oxide Cell (SoC) electrolyzers. Furthermore, fuel cells, across all hydrogen technologies explored, require continuous development to improve their cost-efficiency and streamline their widespread adoption. Nevertheless, the improvement that can be made to reduce the Hydrogen system CAPEX and enhancing its efficiency would make green hydrogen as a competitive and reliable primary storage solution. [ABSTRACT FROM AUTHOR]

Integrated energy system (IES) coupled with renewable energy generation and power-to-gas (P2G) technology provides an effective solution to alleviate the current urgent carbon peak demand. Therefore, This paper develops a novel IES low-carbon economic operation strategy incorporating market mechanism. Firstly, a 24-h joint wind turbine and photovoltaic (WT-PV) output scenario generation method is proposed based on the time-varying Copula function. Secondly, the introduction of carbon capture technology (CCT), electrolyzer (EL), methane reactor (MR) and hydrogen fuel cell (HFC) refines the operation process of p2g into two stages. The combined heat and power (CHP) and HFC variable power operation strategy with adjustable thermoelectric ratio is proposed. Finally, the ladder-type carbon trading mechanism is used to guide IES to control carbon emission. The results of case study show that 1) The time-varying Copula function is effective in improving the scenario accuracy and fitting the data closely to reality 2) The introduction of hydrogen improves the energy utilization efficiency while promoting the consumption of WT-PV. 3) The variable power operation reduces the total cost and carbon emission by 2.4 % and 3.14 %, respectively, compared with the constant thermoelectric ratio. 4) The proposed IES operates reliably and economically under reasonable carbon trading parameters. [ABSTRACT FROM AUTHOR]

Hydrogen has become an important component of the global transition to zero-carbon economies. Low-carbon and green hydrogen gas and fuel cell technology for domestic household use will depend on skilled practitioners, particularly gasfitters, to convert, install, and maintain hydrogen-based appliances. Upskilling gasfitters to work with hydrogen is critical to transitioning from natural gas to hydrogen for heating and cooking. Yet, limited research exists on training and upskilling trade practitioners in the context of renewable energy and low-carbon technologies. This paper makes a novel contribution to research on upskilling for renewable and low-carbon technologies by drawing on the findings from a survey of 1001 plumbers in Australia. The survey, designed using the Theory of Planned Behavior, aimed to predict behaviors regarding hydrogen training and ascertain social and structural enablers for such behavior. The results show that plumbers have limited awareness of hydrogen, yet have positive attitudes towards upskilling to work with the low-carbon fuel. Perceived benefits to business sustainability, customer service and safety underpin the positive attitudes. The research shows that while plumbers are enthusiastic about upskilling for hydrogen, upskilling policies and programs must ensure key stakeholders who inform plumbers' ongoing practice are on board and informed about hydrogen training opportunities. • Plumber/gasfitters expressed a strong positive attitude towards future hydrogen training. • Colleagues/peers and technical regulators were key stakeholders in supporting training. • Behavioral controls do not strongly influence the intention to undertake hydrogen training. • Plumber/gasfitters have limited awareness of hydrogen and transition plans. • Hydrogen training has a dual purpose of upskilling and educating the sector. [ABSTRACT FROM AUTHOR]

Exploring new energy sources for maritime transportation is crucial to address the growing energy crisis and environmental pollution. Full electrified ships have the potential to bring significant economic and environmental benefits. This paper investigates the techno-economics performance such as economic, technical, and emission analyses of three different hybrid systems namely PV/wind/battery (Case I), PV/Wind/battery/Diesel generator (Case II), and PV/Wind/Fuel Cell/battery (Case III) with two different battery technologies (lead acid battery (LAB) and lithium-ion battery (LIB) technologies) for the shipboard microgrid system using HOMER Pro. A load profile of the passenger vessel "FCS Alsterwasser" was considered. Results of the economic analysis from the lead acid batteries combination revealed that Case II emerged as the most cost-effective option, with a net present cost (NPC) of $1.17 million and a levelized electricity (LCOE) cost of $0.295/kWh, while the lithium-ion battery system, Case I proved to be a most economically favorable option, demonstrated the lowest NPC at $1.12 million for and an LCOE of $0.284/kWh. On the contrary, Case I with the LAB system had the highest power production, generating 1,182,870 kWh/yr, and Case III with the LIB system produced the highest power production of 1,368,944 kWh/yr as evident from technical analysis. The emission analysis showed that Case II with the LAB system had higher emissions compared to Case III with the LIB system. The LIB system achieved higher power production and lower emissions than the LAB system. The research study is a step toward sustainable and environmentally friendly energy solutions in maritime transportation. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) are devices that attract the interest for a variety of applications including portable devices, transportation and stationary power. Several models are available in the literature concerning PEMFCs with different modelling approaches. In this paper, two representative dynamic models are examined, one using an electrical equivalent and one based on semi-empirical equations. Moreover, an enhanced model based on semi – empirical equations and a simplified transfer function representation for the dynamic response is proposed. All models can be easily incorporated in power system simulation software. Scope of this paper is to present a parametric analysis method in order to determine the ability of each model to represent accurately the steady – state as well as the slow and fast dynamics of a PEMFC. The influence of each specific parameter is investigated and the tuning procedure is described. Finally, simulation results are presented and the adaptability of all models is evaluated. [ABSTRACT FROM AUTHOR]

The classical boost converter for dc/dc voltage conversion in photovoltaic or fuel cell sources inherits the disadvantage of having a slow dynamical behavior, because of the existence of the right-half plan zero (RHPZ) in its input-to-output transfer function. It is the major challengeable concern in the design of the boost converters needing to work in a continuous-conduction mode. To cancel the right-half plan zero from the transfer function of the classical converters, this paper proposes and analyses a new boost converter with a high voltage gain and minimum phase structure. This converter has a fast dynamic response compared with the conventional boost converter and therefore, it is more suitable for applications with fast dynamic response action to connect an input voltage source to an output load. In order to derive the state-space model of the suggested converter, its steady state performance is studied in details and the essential equations are obtained. The formula of the transfer function is deduced by using the averaging technique and then, the theoretical explanations and assessments are presented to show the main characteristics and superiority of the proposed converter. In addition, a practical hardware system of the designed converter has been built and tested. • Analysis of a new boost converter with capability of the RHPZ elimination and fast dynamic response. • An inclusive comparison between the features of the proposed converter and other minimum phase converters. • Simulations and experimental results are shown to verify the effectiveness of the proposed converter. [ABSTRACT FROM AUTHOR]

In this paper, a phosphoric acid fuel cell integrated with reformer and evaporator is demonstrated. Oxidative steam reforming of methanol (OSRM) process is employed in this system in cooperated with a high efficient evaporator, and the reacted gas is sent into a phosphorus-acid fuel cell (PAFC) for direct power generation after surplus methanol/water filtration. The results show that the maximum power density of this hybrid system achieves 277 mW/cm2 without CO 2 removal, while it achieves 485 mW/cm2 when employing pure hydrogen as the fuel. Image 1 • A phosphoric acid fuel cell integrated with reformer and evaporator is demonstrated. • OSRM Reformer including a high efficient evaporator. • The maximum power density of this system achieves 277 mW/cm2 without CO 2 removal. [ABSTRACT FROM AUTHOR]

In this paper, a phosphoric acid fuel cell integrated with reformer and evaporator is demonstrated. Oxidative steam reforming of methanol (OSRM) process is employed in this system in cooperated with a high efficient evaporator, and the reacted gas is sent into a phosphorus-acid fuel cell (PAFC) for direct power generation after surplus methanol/water filtration. The results show that the maximum power density of this hybrid system achieves 277 mW/cm2 without CO 2 removal, while it achieves 485 mW/cm2 when employing pure hydrogen as the fuel. Image 1 • A phosphoric acid fuel cell integrated with reformer and evaporator is demonstrated. • OSRM Reformer including a high efficient evaporator. • The maximum power density of this system achieves 277 mW/cm2 without CO 2 removal. [ABSTRACT FROM AUTHOR]

The cooling of the open-cathode proton exchange membrane fuel cell (PEMFC) is critical for the operational safety and overall efficiency. However, its control is challenging because of the model uncertainties and frequent disturbances caused by the power adjustment. To this end, this paper proposes a hybrid cooling control strategy by combining the merits of the model-based and data-driven methods. Firstly, a simplified nonlinear mechanistic model is used to exhibit the dynamic perturbations in terms of the different fan speeds and power conditions. Secondly, a modified active disturbance rejection control (ADRC) is developed by incorporating an identified nominal linear model into extended state observer. The external disturbances and the internal uncertainties beyond the nominal model are lumped as a total term, which will be estimated and mitigated in a real-time data-driven manner. The simulation results show that the proposed hybrid method is able to give a faster response with stronger robustness and less noise sensitivity against the uncertainties than the conventional PI and ADRC methods. The experimental test on a 500W open-cathode PEMFC verifies the simulation merits in both set-point tracking and disturbance rejection, depicting a promising prospect of the proposed hybrid method in the open-cathode PEMFC cooling control practice. • The nonlinearity of the fuel cell stack temperature is exhibited. • The uncertainties are accommodated by the data-driven estimation. • The effect of measurement noise is reduced by incorporating model information. • Experiments validate the efficacy of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents new results on the assessment of sustainability indicators for renewable energy (RE) systems (solar PV, wind, phosphoric acid fuel cell, and solid oxide fuel cell). Multi-criteria decision-making (MCDM) model and hybrid Step-wise Weight Assessment Ratio Analysis/Additive Ratio Assessment (SWARA/ARAS) method are used in this study. Five sustainability criteria (resource, environmental, economic, social and technology) and fourteen sub-categories (area, material, energy-construction, energy-fuel, CO 2 -construction, CO 2 -fuel, capital-construction, capital-fuel, delivered cost of energy, current installed capacity, growth rate, capacity factor, system efficiency, and lifetime) are included in this analysis. The extended SWARA and ARAS hybrid method in addition to three energy experts are used in this study for the calculation of sustainability indicators. The final result of this process of ranking the four renewable energy technologies using SWARA-ARAS hybrid method based on the five sustainability criteria and the fourteen subcategories is: (1) wind energy systems (land-based), (2) solid oxide fuel cell, (3) phosphoric acid fuel cell, and (4) solar energy systems (poly-silicon). The MCDM model integrated with the hybrid SWARA/ARAS method is found to be a useful methodology for the sustainability assessment of renewable energy systems, sustainable energy development and decision-making for policy makers. • Sustainability indicators for renewable energy systems: solar PV, wind, and fuel cells. • Multi-criteria decision-making (MCDM) model and hybrid extended SWARA/ARAS method. • Social, environmental, economic, technology and resources criteria were used in this study. • Final ranking of renewable energy systems: (1) wind, (2) fuel cell and (3) solar PV. • Proposed methodology is useful for sustainable energy development and for decision-making for the policy makers. [ABSTRACT FROM AUTHOR]

This paper presents a magnetically coupled hybrid renewable energy system (RES) for residential applications. The proposed system integrates the energies of a set of PV panels, a fuel cell stack, and a battery using a multi-winding magnetic link to supply a residential load. It can operate in multiple grid-connected and off-grid operation modes. An energy management unit including an off-line dynamic programming-based optimization stage and a real-time rule-based controller is designed to optimally control the power flow in the system according to the provided energy plan. The system is designed according to the required standards of the grid-connected residential RES. Different sections of the proposed system including steady-state operation, control techniques, energy management method and hardware design are studied in brief. A prototype of the proposed system is developed and experimentally tested for an energy management scenario considering both sunny and cloudy profiles of the PV generation. The energy distribution and cost analysis approved the benefits of the proposed system for residential consumers. • Combining dynamic programming based optimization and real-time control techniques. • A multi-port multi-operation mode magnetically coupled renewable energy system. • An optimized energy management technique using real-time and forecasted data. • Design of residential renewable energy system according to the recent standards. • Providing energy distribution and energy cost analysis of the system. [ABSTRACT FROM AUTHOR]

The growth mechanism and the corresponding kinetic parameters are valuable to improve the electrodeposition method for preparing Pt-based catalysts. In this paper, the effect of the operation condition on the electrodeposition mechanism has been investigated through experiments and theoretical analysis, and the corresponding kinetic parameters were acquired. The catalytic activity of the deposited Pt catalyst prepared by the pulse current (PC) electrodeposition method was improved, compared with that of the commercial Pt catalyst and the Pt catalyst prepared by the direct current electrodeposition method. The results show that both high current density and high t on /t off in PC electrodeposition could cause large cathode overpotentials, resulting in faster nucleation rate and smaller catalyst particle size, which leads to the better reaction activity of the Pt catalyst. Finally, kinetic parameters including the constants, which relate the nucleation rate with the overpotential, the transfer coefficient and the exchange current density of the electrodeposition process, were determined. • Effect of deposition condition on the electrodeposition mechanism is revealed. • Kinetic parameters for the Pt-electrodeposition are acquired. • PC-deposited Pt shows higher catalytic activity than commercial and DC-deposited Pt. • Increasing applied current and t on / t off lead to small particle and better activity of Pt catalyst. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of different configurations of catalyst (CL), gas diffusion (GDL) and membrane on the performance of the radial flow field fuel cell. To this end, three different radial flow configurations were studied for the first time namely: radial with four channels (R4C), radials with two channels and horizontal MEA (R2CH) and radial with two channels and vertical MEA (R2CV) along with the conventional base fuel cell. Numerical simulations were undertaken for the equal active areas, geometric and boundary conditions including relative humidity and mass flow rates for the cathode and anode sides in all of the configurations. Examining the results of polarization curves, power density and net power demonstrated that the performance of the radial flow fuel cell can be improved significantly without obligating additional cost and only through selecting proper configuration of layers. For instance, the R4C case increases the net power of the fuel cell by 42% compared to the base model, while the R2CV case leads to a power loss by 8% compared to the base model. The results of this work can be adopted to improve the performance of various types of the PEM fuel cells through variation of the layers configuration. • The performance of PEM fuel cell is numerical simulated. • CFD study on reactants distribution, current density and net power was performed. • Three radial flow field configurations were investigated (R4C, R2CH and R2CV). • R4C configuration showed better performance compared to the R2CH and R2CV. [ABSTRACT FROM AUTHOR]

Considering transport applications, there is worldwide an increasing interest in the use of hydrogen-energy for supplying electric powertrains. In order to extend the fuel cell lifespan and to increase its reliability and efficiency, the following features are essential to a fuel cell stack connected DC/DC boost converter: low input current ripple, high voltage gain ratio, high efficiency, high compactness, and high redundancy. Moreover, in order to assess in real time the state-of-health of the fuel cell stack, on-line Electrochemical Impedance Spectroscopy (EIS) functionality integrated with the fuel cell stack connected DC/DC boost converter is a real promising solution requiring no additional measurement equipment. From these points of view, this paper presents a comparison analysis of high voltage gain DC/DC boost converters for fuel cell electric vehicles applications. In addition, some comments and guidelines regarding integration issues are also provided. • The development status of commercialized FCEVs has been generally studied. • Various techniques for FCEV DC/DC converter to gain high performance were compared. • Existed diagnostic methods of fuel cell were comparative studied. • Requirements of converter-based online fuel cell impedance detection were proposed. [ABSTRACT FROM AUTHOR]

Green hydrogen production is facing challenges in balancing economic feasibility with sustainability. Employing efficient hydrogen production designs and benefiting from the potential of hydrogen storage provide two promising strategies to mitigate the economic constraints associated with green hydrogen production. This paper proposes a novel hybrid design for green hydrogen production/utilization based on efficient high-temperature units, including heliostat solar field, solid oxide electrolyzer cell (SOEC), and solid oxide fuel cell (SOFC). The proposed system is comprehensively investigated from thermodynamic and economic perspectives, along with conducting a case study based on hourly electricity prices and actual solar data. The system demonstrates a hydrogen production rate of 7.76 ton/day using the SOEC and a power generation of 54.3 MWh in the SOFC for peak demand shaving, yielding an overall round trip efficiency of 74.2%. The case study results indicate that the economic feasibility is significantly compromised if all the produced hydrogen is sold at prices below 2.75 $/kg; while, implementation of hydrogen storage for peak shaving can yield a promising payback period of less than 2 years. The hydrogen and hourly electricity prices, along with the duration of peak times, are the other critical factors that affect economic viability. [ABSTRACT FROM AUTHOR]

Abstract: This paper evaluates the potential of hybridising renewable technologies to support trigeneration. A model for trigeneration has been developed for simulation and evaluation. The developed trigeneration system aims to be self-sustaining where cooling, heating and power needs of a commercial building are simultaneously fulfilled. The system comprises four key sub-systems, namely, photovoltaic-thermal, solar-thermal, fuel cell, microturbine and absorption chiller-water system. Conventionally, a trigeneration system is analysed based on cost reduction without considering the energy used and the level of carbon dioxide emission. In contrast, this paper presents an analysis of the system using a multi-criteria analysis approach in terms of: (1) operation cost reduction, (2) energy saving; and (3) minimum environmental impact. For the present trigeneration system layout, our result has indicated that a trigeneration system consisting of 80% of microturbine, 10% of photovoltaic-thermal and 10% fuel cell to be the optimum system composition in terms of reducing operational cost, improving energy saving and minimising environment impact. The methodology portrayed in this study provides a pragmatic approach in the design of renewable energy systems to support trigeneration applications. [Copyright &y& Elsevier]

Abstract This paper presents a hybrid power system suitable for powering electric cars, trains and aircraft especially under high fluctuated load demand. The hybrid system includes fuel cells (FC), batteries and supercapacitors (SCs). The energy management strategy (EMS) is a key factor to reduce the total hydrogen consumption and slow down the FC performance degradation. A new EMS based on a recent optimization technique named Salp Swarm Algorithm (SSA) is proposed taking into consideration that the load demand is fully satisfied within the constraints of each energy source. The main objective of the proposed strategy is to minimize the total hydrogen consumption of the system. To minimize the energy obtained from the FC, the energy supplied by the batteries and supercapacitors is maximized. The SSA is an efficient and simple optimizer that needs few numbers of control parameters to be adjusted compared to other optimization algorithms. In order to show the validity of the proposed approach, a comparative study with other conventional approaches such as classical proportional-integral control strategy, frequency decoupling, and state machine (FDSM) control approach, equivalent consumption minimization strategy (ECMS), external energy maximization strategy (EEMS), and genetic algorithm (GA) is presented. In this study, the capstones of the comparison are the total H 2 consumption of the FC and the efficiency of the algorithm. The obtained results confirmed that the proposed SSA approach is superior and efficient than the other strategies. Highlights • SSA is used for optimally distribute the load demand among different components of hybrid power system. • The objective function is maximization of the energy supplied from both batteries and supercapacitors. • The proposed strategy is found superior to the other approaches with consuming 19.9549 gm of hydrogen. • The proposed strategy is found superior to the other approaches with efficiency of 81.22%. • The results confirm SSA has the superiority and validity than the other conventional strategies. [ABSTRACT FROM AUTHOR]

Abstract By using micro-electro-mechanical systems (MEMS), this work develops flexible four-in-one (temperature, voltage, current and flow) micro sensors on a flexible substrate. The flexible four-in-one micro sensors use polyimide as the protective layer, owing to its high temperature resistance. This paper will involve designing and fabricating the flexible four-in-one micro sensors and low-temperature proton exchange membrane fuel cell (LP-PEMFC). A programmable thermal shock tester and a programmable temperature and humidity tester were used to simulate the inner environment of the LP-PEMFC. The calibration curves reveal repeatability and highly linear of the flexible four-in-one micro sensors. After calibrated and its reliability confirmed, the flexible four-in-one micro sensors are inserted into the LP-PEMFC for local microcosmic measurement. In particular, the inside data and performance are monitored to optimize the performance and extend the life of a fuel cell. Highlights • Home-made four-in-one flexible micro sensor can be placed anywhere in a low-temperature proton exchange membrane fuel cell. • Four-in-one flexible micro sensors are four functions, compactness, acid corrosion resistance, good temperature tolerance, quick response. • In-situ diagnosis local temperature, voltage, current and flow information of a low-temperature proton exchange membrane fuel cell. [ABSTRACT FROM AUTHOR]

Abstract For a successful transition to a renewable energy economy, optimisation of renewable energy systems must evolve to take into account not only technical and/or economic objectives, but also environmental and socio-political objectives. A Normalised Weighted Constrained Multi-Objective (NWCMO) meta-heuristic optimisation algorithm has been proposed for achieving a compromise between mutually conflicting technical, economic, environmental and socio-political objectives, in order to simulate and optimise a renewable energy system of any configuration. In this paper, an optimisation methodology based on these four classes of objective is presented. The methodology was implemented using Particle Swarm Optimisation and tested against data from the literature. In the Case Study the original results could be reproduced, but the newly-implemented algorithm was further able to find a more optimal design solution under the same constraints. The influence of additional quantified socio-political inputs was explored. Highlights • Optimisation search technique beyond the traditional approach of techno and/or economic optimisation of energy systems. • Optimisation tool to narrow the gap between research and real-world applications. • More efficient renewable energy system design for technical, economic, environmental and socio-political optimisation. • A novel multi objective optimisation approach of energy systems with conventional and hydrogen fuel cell storage components. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a novel Multi-objective fuzzy self adaptive hybrid particle swarm optimization (MFSAHPSO) evolutionary algorithm to solve the Multi-objective optimal operation management (MOOM) is presented. The purposes of the MOOM problem are to decrease the total electrical energy losses, the total electrical energy cost and the total pollutant emission produced by fuel cells and substation bus. Conventional algorithms used to solve the multi-objective optimization problems convert the multiple objectives into a single objective, using a vector of the user-predefined weights. In this conversion several deficiencies can be detected. For instance, the optimal solution of the algorithms depends greatly on the values of the weights and also some of the information may be lost in the conversion process and so this strategy is not expected to provide a robust solution. This paper presents a new MFSAHPSO algorithm for the MOOM problem. The proposed algorithm maintains a finite-sized repository of non-dominated solutions which gets iteratively updated in the presence of new solutions. Since the objective functions are not the same, a fuzzy clustering technique is used to control the size of the repository, within the limits. The proposed algorithm is tested on a distribution test feeder and the results demonstrate the capabilities of the proposed approach, to generate true and well-distributed Pareto-optimal non-dominated solutions of the MOOM problem. [ABSTRACT FROM AUTHOR]

Abstract: The design of the flow field greatly affects the flow distribution and the final performance of the proton exchange membrane fuel cell (PEMFC) system. The clamping force between the gas diffusion layer (GDL) and the flow field plate (FFP) will cause the inhomogeneous compression of the GDL. Then the GDL will be intruded into the reactant gas channels and eventually change the flow distribution. This paper presents a study on the effect of the intrusion of the GDL on the flow field in a PEMFC, and tries to explain the reason for poor performance of the previous design of the flow field other than those have been studied in other papers such as GDL roughness, porosity, etc. First of all, a linear analytical model is used to analyze the sensitivities of the flow field to the GDL intrusion, and then used to estimate the effect of the GDL intrusion on the flow field distribution. Secondly, a multi-objective optimization model is proposed to eliminate the nonuniform distribution in the flow field with the GDL intrusion taken into consideration. Subsequently, three different designs are analyzed and compared with each other as a demonstration to show the effect of the GDL intrusion. From the analysis results, it is recommended that the effect of the GDL intrusion on the multi-depth flow field should be taken into consideration and the flow field should be insensitive to the GDL intrusion to obtain high robust performance. The results obtained in the study provide the designer some useful guidelines in the concept design of flow field configurations. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the efficiency properties of the single fuel cell and the fuel cell stack have been analyzed theoretically, and the efficiency models of the fuel cell stack and fuel cell engine (FCE) are developed. Through experimental studies, we analyze the relationships between (1) the efficiency of the fuel cell stack and its current, (2) the efficiency of the fuel cell stack and its power, (3) the efficiency of the fuel cell stack and the hydrogen consumption ratio, (4) the efficiency of the FCE and the fuel cell stack current, (5) the efficiency of the FCE and its power, and (6) the efficiency of the FCE and the hydrogen consumption ratio. The factors which affect the efficiency of the fuel cell stack and that of the FCE are discussed. Finally, the efficiency models of the fuel cell stack and the FCE discussed in this paper are verified by test data. The results show that the simulation values fit well with the test data, and they can be applied in the fuel cell vehicle simulation studies. [Copyright &y& Elsevier]