Modeling of Hydrogen Production in an Alkaline Electrolyser System Connected with a Solar Photovoltaic Panel or a Wind Turbine: Case Study;Douala-Cameroon

This article is in the field of research into the storage of renewable energy production. One of the main obstacles to the rapid development of renewable energies is the storage of the energy produced at low cost and with good efficiency. The production of hydrogen from renewable energies is a promising solution. The present work evaluates the potential of hydrogen production by electrolysis from solar photovoltaic and wind renewable energies in the city of Douala in Cameroon. The methodological approach used is based on the semi-empirical modelling approach of an alkaline electrolyser associated with the solar panel or the wind turbine. The simulation results obtained on the MATLAB/Simulink platform show that the average hydrogen production potential is estimated at 0.55 Nm3/h for a PV panel supply, which corresponds to average energy efficiency of 70%, and at 0.675 Nm3/h for a wind turbine supply, which corresponds to average energy efficiency of 84%. These results show the need to promote this technology, whose efficiency can be improved depending on the choice of site.

Design and fabrication of bipolar plates for PEM water electrolyser

Hydrogen energy,whether in generation plants or utilization facilities,plays a decisive role in the mission to achieve net-zero greenhouse gas emissions,all to minimize pollution.The growing demand for clean energy carrier steadily accelerates the development of hydrogen production processes,and therein proton exchange membrane(PEM)water electrolysis is deemed a promising long-term strategy for hydrogen preparation and collection.This review retrospects recent developments and applications of bipolar plates(BPs)as key components in PEM fuel cells and water electrolysers.The main content includes multifaceted challenges in the R&D or fabrication of BPs and potential future trends have also been proposed.Specific details cover the BPs matrix(metallic materials and carbon composites)and the surface coating types(metal and compound coatings,carbon-based coatings,and polymer coatings),as well as the influence of flow field design for mass transport.Long-term development and feasible researches of BPs are prospected.Especially in the following aspects:(1)Structural and functional integration of components,such as material fabrication and flow field geometry optimization using 3D printing technology;(2)Introduction of environment-friendly renewable energy for hydrogen production;(3)Research on hydrogen energy reversible systems;(4)Composition optimization of surface coatings based on computational materials science and(5)systematic design expected to evolve into the next generation of BPs.

Novel integrated three-port DC/DC converter for different operating modes between renewable energy,electrolyser and fuel cell/battery

Due to the slow dynamic power-regulation characteristics of the electrolyser(EL),a novel integrated three-port DC/DC converter topology based on a phase-shifted full-bridge converter and dual active-bridge converter is proposed in this paper.Especially,the proposed converter can achieve a fast auxiliary response to the EL.This topology has the features of single-stage conversion,high system integration and compatibility with multiple operation modes.The operational principles and a hybrid modulation scheme of the proposed converter are analysed in detail.In addition,the power-transmission characteristics of each port and the soft-switching range are researched.On these bases,six operation modes suitable for a hydrogen energy-storage system are designed.The simulation and a 2-kW scaled-down experimental prototype are established to verify the feasibility and effectiveness of the proposed topology in different operation modes.

Facilitating Water electrolysers for electricity-grid services in Europe through establishing standardized testing protocols

Electrolysers,which convert electricity into hydrogen,have the potential to offer a variety of electrical-grid services,therefore facilitating the integration of intermittent renewables into electrical grids.Among various activities that aim to unlock this hidden value,the 3-year European Union project QualyGridS launched in 2017 aims to establish standardized testing protocols for electrolysers to perform electricity-grid services.This paper shares experience and intermediate results of QualyGridS with respect to the testing protocols,test benches and testing results.The results of this work facilitate mutual understanding between the electricity industry and the hydrogen industry,support further development of the cross-sector testing standards,guide the design and selection of grid-service-oriented electrolyser applications and foster the transition towards a fossil-free-energy future based on high shares of hydrogen and other renewable solutions.

Perovskite Sr0.9Fe0.9Zr0.1O3-δ:Redox-stable Structure,Oxygen Vacancy,Electrical Properties and Steam Electrolysis Performance

Many researchers have studied on perovskite oxide for its unique structure.Perovskite oxides,ABO3-δ,with different A and B metals have shown wide applications in many fields,in particular solid oxide electrolysers.SrFeO3-δ,typical perovskite oxides,in which iron is the mixed-valence cation with the capacity to change the chemical valence,have a wide range of oxygen nonstoichiometry.In this study,Sr（0.9）Fe（0.9）Zr（0.1）O3-δ（SFZO） is synthesized and then treated in 5%H2/Ar and air at high temperature,exhibiting excellent redox stability.Redox-stable structure,oxygen vacancy and electrical properties of SFZO are investigated.Steam electrolysis is then performed with SFZO cathode under 5%H2O/5%H2/Ar and 5%H2O/Ar atmospheres,respectively.The present results indicate that the SFZO is a novel promising cathode material for solid oxide steam electrolyser.

Efficient CO_2 Electrolysis with Fluorite Structure Nanoparticles Modified Perovskite Structure La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3-δ) Cathode

Perovskite structure La_（0.75）Sr_（0.25）Cr_（0.5）Mn_（0.5）O_（3-δ）（LSCM） cathode with unique structure can electrolyze CO_2 to CO in solid oxide electrolysers（SOEs）.However,the cell performance is restricted by its electro-catalysis activity.In this work,fluorite structure nanoparticles（CeO_（2-δ）） are impregnated on LSCM cathode to improve the electro-catalysis activity.X-ray diffraction（XRD）,scanning electron microscope（SEM） and X-ray photoelectron spectroscopy（XPS） together approve that the fluorite structure nanoparticles are uniformly distributed on the perovskite structure LSCM scaffold.Electrochemical measurements illustrate that direct CO_2 electrolysis with 10%mol CeO_（2-δ） impregnated LSCM cathode exhibits excellent performance for current density（0.5 A×cm^（-2）） and current efficiency（～95%） at 800 ℃ under 1.6 V.It is believed that the enhanced performance of directed CO_2 electrolysis may be due to the synergetic effect of fluorite structure CeO_（2-δ） nanoparticles and perovskite structure LSCM ceramic electrode.

THERMOCOUPLE USED FOR TEMPERATURE MEASUREMENT OF ALUMINIUM CELLS BY DYNAMIC METHOD

ＴＨＥＲＭＯＣＯＵＰＬＥＵＳＥＤＦＯＲＴＥＭＰＥＲＡＴＵＲＥＭＥＡＳＵＲＥＭＥＮＴＯＦＡＬＵＭＩＮＩＵＭＣＥＬＬＳＢＹＤＹＮＡＭＩＣＭＥＴＨＯＤ￥Ｙｕ，Ｘｕｅｂｉｎ（ＩｎｓｔｉｔｕｔｅｏｆＣｏｍｐｏｓｉｔｅＭａｔｅｒｉａｌ，ＪｉａｏＴｏｎｇＵｎｉｖｅ...

具有超高碱性稳定性和尺寸稳定性的聚芳烃N-甲基奎宁基阴离子交换膜

阴离子交换膜水电解槽的阴离子交换膜成本低、无需铂族贵金属催化剂,有望取代高成本的质子交换膜水电解槽.然而,阴离子交换膜的尺寸稳定性差以及在高温、高浓度碱液中的稳定性差,阻碍了阴离子交换膜水电解槽的发展.最近,我们合成了一种具有优异碱性稳定性的聚(三苯基-N-甲基奎宁基)阴离子交换膜,为了进一步提高这种阴离子交换膜的机械强度和尺寸稳定性,在本工作中,我们添加了三氟苯乙酮来制备聚(三苯基-三氟苯乙酮-N-甲基奎宁基)阴离子交换膜.这种共聚阴离子交换膜具有超高的碱性稳定性(在80℃,10 mol L^(-1)的NaOH溶液中浸泡1600小时后OH^(-)电导率和机械强度不发生衰减),优异的尺寸稳定性(30–80℃温度下,纯水中溶胀率不超过7%;10 mol L^(-1)的NaOH溶液中溶胀率不超过2%),高氢氧根电导率(80°C时达134.5 mS cm^(-1))和高机械强度(抗拉伸强度达43.2 MPa).这种阴离子交换膜和镍合金泡沫电极组装的简易水电解槽在80°C下,2.0 V和5 mol L^(-1)的KOH水电解质中具有1780 mA cm^(-2)的优异电流密度,并且具有高耐久性.

Comprehensive Optimization-based Techno-economic Assessment of Hybrid Renewable Electricity-hydrogen Virtual Power Plants

Hydrogen is being considered as an important option to contribute to energy system decarbonization.However,currently its production from renewables is expensive compared with the methods that utilize fossil fuels.This paper proposes a comprehensive optimization-based techno-economic assessment of a hybrid renewable electricity-hydrogen virtual power plant(VPP)that boosts its business case by co-optimizing across multiple markets and contractual services to maximize its profits and eventually deliver hydrogen at a lower net cost.Additionally,multiple possible investment options are considered.Case studies of VPP placement in a renewable-rich,congested area of the Australian network and based on real market data and relevant sensitivities show that multi-market participation can significantly boost the business case for cleaner hydrogen.This highlights the importance of value stacking for driving down the cost of cleaner hydrogen.Due to the participation in multiple markets,all VPP configurations considered are found to be economically viable for a hydrogen price of 3 AUD$/kg(2.25 USD$/kg),which has been identified as a threshold value for Australia to export hydrogen at a competitive price.Additionally,if the high price volatility that has been seen in gas prices in 2022(and by extension electricity prices)continues,the flexibility of hybrid VPPs will further improve their business cases.

Techno-economic analysis of green hydrogen as an energy-storage medium for commercial buildings

Green-hydrogen production is vital in mitigating carbon emissions and is being adopted globally.In its transition to a more diverse energy mix with a bigger share for renewable energy,United Arab Emirates(UAE)has committed to investing billions of dollars in the production of green hydrogen.This study presents the results of the techno-economic assessment of a green-hydrogen-based commercial-building microgrid design in the UAE.The microgrid has been designed based on the building load demand,green-hydrogen production potential utilizing solar photovoltaic(PV)energy and discrete stack reversible fuel cell electricity generation during non-PV hours.Given the current market conditions and the hot humid climate of the UAE,a performance analysis is derived to evaluate the technical and economic feasibility of this microgrid.The study aims at maximizing both the building microgrid’s independence from the main grid and its renewable fraction.Simulation results indicate that the designed system is capable of meeting three-quarters of its load demand independently from the main grid and is supported by a 78%renewable-energy fraction.The economic analysis demonstrates a 3.117-$/kg levelized cost of hydrogen production and a 0.248-$/kWh levelized cost for storing hydrogen as electricity.Additionally,the levelized cost of system energy was found to be less than the current utility costs in the UAE.Sensitivity analysis shows the significant impact of the capital cost and discount rate on the levelized cost of hydrogen generation and storage.

Electrifying the future:the advances and opportunities of electrocatalytic carbon dioxide reduction in acid

Transforming carbon dioxide(CO_(2))into products using renewable electricity is a crucial and captivating quest for a green and circular economy.Compared with commonly used alkali electrolytes,acidic media for electrocatalytic CO_(2) reduction(CO_(2)RR)boasts several advantages,such as high carbon utilization efficiency,high overall energy utilization rate,and low carbonate formation,making it a compelling choice for industrial applications.However,the acidic CO_(2)RR also struggles with formidable hurdles,encompassing the fierce competition with the hydrogen evolution reaction,the low CO_(2) solubility and availability,and the suboptimal performance of catalysts.This review provides a comprehensive overview of the CO_(2)RR in acidic media.By elucidating the underlying regulatory mechanism,we gain valuable insights into the fundamental principles governing the acidic CO_(2)RR.Furthermore,we examine cutting-edge strategies aimed at optimizing its performance and the roles of reactor engineering,especially membrane electrode assembly reactors,in facilitating scalable and carbon efficient conversion.Moreover,we present a forward-looking perspective,highlighting the promising prospects of acidic CO_(2)RR research in ushering us towards a carbon-neutral society.

Enhanced CO2 Electrolysis with Metal-oxide Interface Structures

The ever-decreasing fossil fuels and the increasing greenhouse effect have caused substantial concern.Solid oxide electrolyser cell(SOEC)with La_(0.75)Sr_(0.25)Cr_(0.5 )Mn_(0.5)O_(3-δ)(LSCM)as a cathode was used for CO_(2) electrolysis to CO.In this work,the metal-oxide interface was constructed on the LSCM framework by in-situ exsolution and impregnation,and the uniform distribution of metal nanoparticles on the LSCM framework was confirmed by spectroscopy techniques and electron microscopy techniques.The existence of three-phase boundary promoted the absorption and electrolysis of CO_(2).(La_(0.75) Sr_(0.25))0.9(Cr_(0.5 )Mn_(0.5))_(0.9)(Ni_(0.5) Cu_(0.5))_(0.1) O_(3-δ)(LSCMNC)showed the best electrolytic CO_(2) performance at 850℃and exhibited excellent electrocatalytic activity after 100 hours of long-term testing and 8 redox cycles.

Enhanced CO2 Electrolysis with Mn-doped SrFeO3-δ Cathode

Solid oxide carbon dioxide electrolysers are expected to play a key role in carbon-neutral energy landscape.However,the limited activity of traditional ceramic cathodes still restricts the electrochemical performance.Here we report the doping of Mn at the B site of SrFeO3-δcathode to improve CO2 electrolysis.The oxygen vacancy concentration is increased by^30%with Mn doping while the surface oxygen exchange coefficients are enhanced by^10 times.The chemisorption of CO2 indicates the presence of chemical intermediate state between CO2 molecule and carbonate ion on the oxygen-deficient cathode surface which therefore leads to the desorption temperature of^800℃.The Mn-doped SrFeO3-δenhances CO2 electrolysis with no performance degradation being observed even after high-temperature operation of 100 hours.

Red cabbage washing with acidic electrolysed water:effects on microbial quality and physicochemical properties

The effects of acidic electrolysed water(AEW)as‘green’technology on the microbiological and physicochemical properties of fresh-cut red cabbages were studied.Fresh-cut red cabbages and artificially inoculated red cabbages with Salmonella typhimurium DT104 were washed with distilled water(DW)and different available chlorine concentrations(ACC)of AEW for different times.AEW treatments significantly reduced the populations of native aerobic bacteria,molds,and yeasts,and artificially inoculated S.typhimurium DT104 compared with the DW-treated and untreated red cabbage samples.The effectiveness of AEW treatments was greatly enhanced with increasing ACC and treatment times.S.typhimurium DT104 were not detected in the washing water that were collected after the red cabbages treated by AEW.The surface colour,pH,and total phenolic contents did not significantly change when the red cabbages were washed with DW and AEW containing 100 mg/L available chlorine for 3 min.The anthocyanin contents and antioxidant activities of red cabbage were significantly reduced by 18.5 per cent for cyanidin,22.1 per cent for pelargonidin,and 11.2 per cent for 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity,however,the impacts on the nutritional benefits of red cabbage were considered as limited and acceptable.The optimal process condition of AEW for washing red cabbage was 100 mg/L ACC for 3 min.In these conditions,most of the native microflora were inactivated,and artificially inoculated S.typhimurium DT104 on the red cabbage were reduced by 40.2 per cent[3.67 log CFU/g(log10 colony-forming units per gram)]and with minimal losses of nutrients and antioxidant activity,as well as no requirement of decontamination treatment on the washing water after AEW treatment.

Nanometer-sized passageways within CuTCNQ crystalline grains prepared by spontaneous electrolyses

Since R. S. Potember and his co-operators reported in 1979 that there was a cur-rent-controlled bistable electrical switching phenomenon in the copper charge-transfer (CT)comples of 7, 7’, 8, 8’-tetracyanoquinodimethane (TCNQ), electric, optoelectronic threshold-switching and memory effects have been found in succession within the copper and silverCT complexes of TCNQ and its derivatives. These potential characteristics usually corre-spond to a field-induced partial phase transition in material that generates either a