Production & Supply Chain
Multi-Criteria Optimization of a Biomass-Based Hydrogen Production System Integrated With Organic Rankine Cycle
Oct 2020
Publication
Biomass-based gasification is an attractive and promising pathway for hydrogen production. In this work a biomass-based hydrogen production system integrated with organic Rankine cycle was designed and investigated to predict the performance of hydrogen production yield and electricity generation under various operating conditions. The modified equilibrium model presented desirable results for the produced syngas compositions compared with the experimental data. Hydrogen yields from four types of biomass (wood chips daily manure sorghum and grapevine pruning wastes) were compared under the same operating condition with wood chips exhibiting the maximum hydrogen yield of 11.59 mol/kg. The effects of gasification temperature equivalence ratio and steam-to-biomass ratio on the hydrogen yield and electricity generation were investigated by using the response surface method. Furthermore the system was optimized using a genetic algorithm based on the response surface model. A preferred optimal solution with a hydrogen yield of 39.31 mol/kg and an output power of 3558.08 kW (0.99 kW h/kg) was selected by the linear programming technique for multidimensional analysis of the preference method.
Exploring the Capability of Mayenite (12CaO·7Al2O3) as Hydrogen Storage Material
Mar 2021
Publication
We utilized nanoporous mayenite (12CaO·7Al2O3) a cost-effective material in the hydride state (H−) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H− ions trapped in the structure which could allow the use of this material in future portable applications. Additionally this material is 100% recyclable because the cage structure can be recovered by heat treatment after hydrogen desorption. The presence of hydrogen molecules as H− ions was confirmed by 1H-NMR gas chromatography and neutron diffraction analyses. We confirmed the hydrogen state stability inside the mayenite cage by the first-principles calculations to understand the adsorption mechanism and storage capacity and to provide a key for the use of mayenite as a portable hydrogen storage material. Further we succeeded in introducing H− directly from OH− by a simple process compared with previous studies that used long treatment durations and required careful control of humidity and oxygen gas to form O2 species before the introduction of H−.
Insights into the Principles, Design Methodology and Applications of Electrocatalysts Towards Hydrogen Evolution Reaction
Apr 2021
Publication
The electrolysis of water for sustainable hydrogen producing is a crucial segment of various emerging clean-energy technologies. However pursuing an efficient and cheap alternative catalyst to substitute state-of-the-art platinum-group electrocatalysts remains a prerequisite for the commercialization of this technology. Typically precious-metal-free catalysts have always much lower activities towards hydrogen production than that of Pt-group catalysts. To explore high-performance catalysts maximally exposed active sites rapid charge transfer ability and desirable electronic configuration are essentially demanded. Herein the fundamentals of hydrogen evolution reaction will be briefly described and the main focus will be on the interfacial engineering strategies by means of constructing defect structure creating heterojunction phase engineering lattice strain control designing hierarchical architecture and doping heteroatoms to effectively proliferate the catalytic active sites facilitate the electron diffusion and regulate the electronic configuration of numerous transition metals and their nitrides carbides sulfides phosphides as well as oxides achieving a benchmark performance of platinum-free electrocatalysts for the hydrogen evolution reaction. This review unambiguously offers proof that the conventional cheap and earth-abundant transition metal-based substances can be translated into an active water splitting catalyst by the rational and controllable interfacial designing.
High-Purity and Clean Syngas and Hydrogen Production From Two-Step CH4 Reforming and H2O Splitting Through Isothermal Ceria Redox Cycle Using Concentrated Sunlight
Jul 2020
Publication
The thermochemical conversion of methane (CH4) and water (H2O) to syngas and hydrogen via chemical looping using concentrated sunlight as a sustainable source of process heat attracts considerable attention. It is likewise a means of storing intermittent solar energy into chemical fuels. In this study solar chemical looping reforming of CH4 and H2O splitting over non-stoichiometric ceria (CeO2/CeO2−δ) redox cycle were experimentally investigated in a volumetric solar reactor prototype. The cycle consists of (i) the endothermic partial oxidation of CH4 and the simultaneous reduction of ceria and (ii) the subsequent exothermic splitting of H2O and the simultaneous oxidation of the reduced ceria under isothermal operation at ~1000°C enabling the elimination of sensible heat losses as compared to non-isothermal thermochemical cycles. Ceria-based reticulated porous ceramics with different sintering temperatures (1000 and 1400°C) were employed as oxygen carriers and tested with different methane flow rates (0.1–0.4 NL/min) and methane concentrations (50 and 100%). The impacts of operating conditions on the foam-averaged oxygen non-stoichiometry (reduction extent δ) syngas yield methane conversion solar-to-fuel energy conversion efficiency as well as the effects of transient solar conditions were demonstrated and emphasized. As a result clean syngas was successfully produced with H2/CO ratios approaching 2 during the first reduction step while high-purity H2 was subsequently generated during the oxidation step. Increasing methane flow rate and CH4 concentration promoted syngas yields up to 8.51 mmol/gCeO2 and δ up to 0.38 at the expense of enhanced methane cracking reaction and reduced CH4 conversion. Solar-to-fuel energy conversion efficiency namely the ratio of the calorific value of produced syngas to the total energy input (solar power and calorific value of converted methane) and CH4 conversion were achieved in the range of 2.9–5.6% and 40.1–68.5% respectively.
Green Hydrogen: A New Flexibility Source for Security Constrained Scheduling of Power Systems with Renewable Energies
Apr 2021
Publication
Green hydrogen i.e. the hydrogen generated from renewable energy sources (RES) will significantly contribute to a successful energy transition. Besides to facilitate the integration and storage of RES this promising energy carrier is well capable to efficiently link various energy sectors. By introduction of green hydrogen as a new flexibility source to power systems it is necessary to investigate its possible impacts on the generation scheduling and power system security. In this paper a security-constrained multi-period optimal power flow (SC-MPOPF) model is developed aiming to determine the optimal hourly dispatch of generators as well as power to hydrogen (P2H) units in the presence of large-scale renewable energy sources (RES). The proposed model characterizes the P2H demand flexibility in the proposed SC-MPOPF model taking into account the electrolyzer behavior reactive power support of P2H demands and hydrogen storage capability. The developed SC-MPOPF model is applied to IEEE 39-bus system and the obtained numerical results demonstrate the role of P2H flexibility on cost as well as RES's power curtailment reduction.
A Mountain to Climb? Tracking Progress in Scaling Up Renewable Gas Production in Europe
Oct 2019
Publication
In the last couple of years there has been increasing recognition by key players in the European gas industry that to mitigate the risk of terminal decline in the context of a decarbonising energy system there will need to be rapid scale up of decarbonised gas. This has led to several projections of the scale of decarbonised gas which could potentially be supplied by 2030 2040 or 2050. This paper joint with the Sustainable Gas Institute at Imperial College London considers the very significant rate of scale up and the significant cost reductions contemplated by such projections. Based on a database of actual announced projects (both committed and in earlier stages of development) for production of decarbonised gas it then considers the extent to which project activity is consistent with meeting the ambitious projections. It identifies a significant gap in current levels of activity largely because there is not yet sufficient economic incentive for investors to develop the required projects. It is intended that this paper will form the basis of continued tracking of the level of activity over the coming years to help inform industry players of further actions which may be required.
Experimental and Theoretical Insights to Demonstrate the Hydrogen Evolution Activity of Layered Platinum Dichalcogenides Electrocatalysts
Mar 2021
Publication
Hydrogen is a highly efficient and clean renewable energy source and water splitting through electrocatalytic hydrogen evolution is a most promising approach for hydrogen generation. Layered transition metal dichalcogenides-based nano-structures have recently attracted significant interest as robust and durable catalysts for hydrogen evolution. We systematically investigated the platinum (Pt) based dichalcogenides (PtS2 PtSe2 and PtTe2) as highly energetic and robust hydrogen evolution electrocatalysts. PtTe2 catalyst unveiled the rapid hydrogen evolution process with the low overpotentials of 75 and 92 mV (vs. RHE) at a current density of 10 mA cm−2 and the small Tafel slopes of 64 and 59 mV/dec in acidic and alkaline medium respectively. The fabricated PtTe2 electrocatalyst explored a better catalytic activity than PtS2 and PtSe2. The density functional theory estimations explored that the observed small Gibbs free energy for H-adsorption of PtTe2 was given the prominent role to achieve the superior electrocatalytic and excellent stability activity towards hydrogen evolution due to a smaller bandgap and the metallic nature. We believe that this work will offer a key path to use Pt based dichalcogenides for hydrogen evolution electrocatalysts.
Analyzing the Necessity of Hydrogen Imports for Net-zero Emission Scenarios in Japan
Jun 2021
Publication
With Japan’s current plans to reach a fully decarbonized society by 2050 and establish a hydrogen society substantial changes to its energy system need to be made. Due to the limited land availability in Japan significant amounts of hydrogen are planned to be imported to reach both targets. In this paper a novel stochastic version of the open-source multi-sectoral Global Energy System Model in conjunction with a power system dispatch model is used to analyze the impacts of both availability and price of hydrogen imports on the transformation of the Japanese energy system considering a net-zero emission target. This analysis highlights that hydrogen poses a valuable resource in specific sectors of the energy system. Therefore importing hydrogen can indeed positively impact energy system developments although up to 19mt of hydrogen will be imported in the case with the cheapest available hydrogen. In contrast without any hydrogen imports power demand nearly doubles in 2050 compared to 2019 due to extensive electrification in non-electricity sectors. However hydrogen imports are not necessarily required to reach net-zero emissions. In all cases however large-scale investments into renewable energy sources need to be made.
A Production and Delivery Model of Hydrogen from Solar Thermal Energy in the United Arab Emirates
May 2022
Publication
Hydrogen production from surplus solar electricity as energy storage for export purposes can push towards large-scale application of solar energy in the United Arab Emirates and the Middle East region; this region’s properties of high solar irradiance and vast empty lands provide a good fit for solar technologies such as concentrated solar power and photovoltaics. However a thorough comparison between the two solar technologies as well as investigating the infrastructure of the United Arab Emirates for a well-to-ship hydrogen pathway is yet to be fully carried out. Therefore in this study we aim to provide a full model for solar hydrogen production and delivery by evaluating the potential of concentrated solar power and photovoltaics in the UAE then comparing two different pathways for hydrogen delivery based on the location of hydrogen production sites. A Solid Oxide Cell Electrolyzer (SOEC) is used for technical comparison while the shortest routes for hydrogen transport were analyzed using Geographical Information System (GIS). The results show that CSP technology coupled with SOEC is the most favorable pathway for large-scale hydrogen from solar energy production in the UAE for export purposes. Although PV has a slightly higher electricity potential compared to CSP around 42 GWh/km2 to 41.1 GWh/km2 respectively CSP show the highest productions rates of over 6 megatons of hydrogen when the electrolyzer is placed at the same site as the CSP plant while PV generates 5.15 megatons when hydrogen is produced at the same site with PV plants; meanwhile hydrogen from PV and CSP shows similar levels of 4.8 and 4.6 megatons of hydrogen respectively when electrolyzers are placed at port sites. Even considering the constraints in the UAE’s infrastructure and suggesting new shorter electrical transmission lines that could save up to 0.1 megatons of hydrogen in the second pathway production at the same site with CSP is still the most advantageous scenario.
A Techno-Economic Analysis of Solar Hydrogen Production by Electrolysis in the North of Chile and the Case of Exportation from Atacama Desert to Japan
Aug 2020
Publication
H2 production from solar electricity in the region of the Atacama Desert – Chile – has been identified as strategical for global hydrogen exportation. In this study the full supply chain of solar hydrogen has been investigated for 2018 and projected to scenarios for 2025-2030. Multi-year hourly electrical profiles data have been used from real operating PV plants and simulated Concentrated Solar Power “CSP” plants with Thermal Energy Storage “TES” as well as commercial electricity Power Purchase Agreement “PPA” prices reported in the Chilean electricity market were considered. The Levelized Cost of Hydrogen “LCOH” of each production pathway is calculated by a case-sensitive techno-economic MATLAB/Simulink model for utility scale (multi-MW) alkaline and PEM electrolyser technologies. Successively different distribution storage and transportation configurations are evaluated based on the 2025 Japanese case study according to the declared H2 demand. Transport in the form of liquefied hydrogen (LH2) and via ammonia (NH3) carrier is compared from the port of Antofagasta CL to the port of Osaka JP.
Volumetric Analysis Technique for Analyzing the Transport Properties of Hydrogen Gas in Cylindrical-shaped Rubbery Polymers
Mar 2021
Publication
We report volumetric analysis techniques to analyze the transport properties of hydrogen dissolved in cylindrical-shaped polymers. The techniques utilize the volume measurement of the released hydrogen from rubber by gas collection in a graduated cylinder after charging sample with high-pressure hydrogen and subsequent decompression. We further improve the graduated cylinder with some modifications such as reading the electrical capacitance of the water level using electrodes and changing the sample loading position. From the measurement results the uptake (C∞) diffusion coefficient (D) and solubility (S) of hydrogen are quantified with an upgraded diffusion analysis program. These methods are applied to three cylindrical rubbers. Dual adsorption behaviors with increasing pressure are observed for all the samples. C∞ follows Henry’s law up to ~15 MPa whereas Langmuir model applies up to 90 MPa. D shows Knudsen and bulk diffusion behavior below and above pressure respectively. A COMSOL simulation is compared with experimental observations.
Nuclear-Renewables Energy System for Hydrogen and Electricity Production
May 2011
Publication
In the future the world may have large stranded resources of low-cost wind and solar electricity. Renewable electricity production does not match demand and production is far from major cities. The coupling of nuclear energy with renewables may enable full utilization of nuclear and renewable facilities to meet local electricity demands and export pipeline hydrogen for liquid fuels fertilizer and metals production. Renewables would produce electricity at full capacity in large quantities. The base-load nuclear plants would match electricity production with demand by varying the steam used for electricity versus hydrogen production. High-temperature electrolysis (HTE) would produce hydrogen from water using (a) steam from nuclear plants and (b) electricity from nuclear plants and renewables. During times of peak electricity demand the HTE cells would operate in reverse fuel cell mode to produce power substituting for gas turbines that are used for very few hours per year and that thus have very high electricity costs. The important net hydrogen production would be shipped by pipeline to customers. Local hydrogen storage would enable full utilization of long-distance pipeline capacity with variable production. The electricity and hydrogen production were simulated with real load and wind data to understand under what conditions such systems are economic. The parametric case study uses a wind-nuclear system in North Dakota with hydrogen exported to the Chicago refinery market. North Dakota has some of the best wind conditions in the United States and thus potentially low-cost wind. The methodology allows assessments with different economic and technical assumptions - including what electrolyzer characteristics are most important for economic viability.
Modeling of a High Temperature Heat Exchanger to Supply Hydrogen Required by Fuel Cells Through Reforming Process
Sep 2021
Publication
Hydrogen as a clean fuel and a new energy source can be produced by various methods. One of these common and economical methods of hydrogen production is hydrocarbon vapor modification. This research studies hydrogen production using a propane steam reforming process inside a high temperature heat exchanger. The application of this high temperature heat exchanger in the path of the power supply line is a fuel cell stack unit to supply the required hydrogen of the device. The heat exchanger consists of a set of cylindrical tubes housed inside a packed-bed called a reformer. The energy required to perform the reaction is supplied through these tubes in which high temperature gas is injected and the heat exchanger is insulated to prevent energy loss. The results show that at maximum temperature and velocity of hot gases (900 K and 1.5 m s−1 ) complete consumption of propane can be observed before the outlet of the reformer. Also in the mentioned conditions the maximum hydrogen production (above 92%) is obtained. The best permeability under which the system can perform best is 1×10−9 m2.
Hydrogen Production through Autothermal Reforming of Ethanol: Enhancement of Ni Catalyst Performance via Promotion
Aug 2021
Publication
Autothermal reforming of bioethanol (ATR of C2H5OH) over promoted Ni/Ce0.8La0.2O1.9 catalysts was studied to develop carbon-neutral technologies for hydrogen production. The regulation of the functional properties of the catalysts was attained by adjusting their nanostructure and reducibility by introducing various types and content of M promoters (M = Pt Pd Rh Re; molar ratio M/Ni = 0.003–0.012). The composition–characteristics–activity correlation was determined using catalyst testing in ATR of C2H5OH thermal analysis N2 adsorption X-ray diffraction transmission electron microscopy and EDX analysis. It was shown that the type and content of the promoter as well as the preparation mode (combined or sequential impregnation methods) determine the redox properties of catalysts and influence the textural and structural characteristics of the samples. The reducibility of catalysts improves in the following sequence of promoters: Re < Rh < Pd < Pt with an increase in their content and when using the co-impregnation method. It was found that in ATR of C2H5OH over bimetallic Ni-M/Ce0.8La0.2O1.9 catalysts at 600 ◦C the hydrogen yield increased in the following row of promoters: Pt < Rh < Pd < Re at 100% conversion of ethanol. The introduction of M leads to the formation of a NiM alloy under reaction conditions and affects the resistance of the catalyst to oxidation sintering and coking. It was found that for enhancing Ni catalyst performance in H2 production through ATR of C2H5OH the most effective promotion is with Re: at 600 ◦C over the optimum 10Ni-0.4Re/Ce0.8La0.2O1.9 catalyst the highest hydrogen yield 65% was observed.
The Potential of Green Ammonia Production to Reduce Renewable Power Curtailment and Encourage the Energy Transition in China
Apr 2022
Publication
The pursuing of inter-regional power transmission to address renewable power curtailment in China has resulted in disappointing gains. This paper evaluates the case of local green ammonia production to address this issue. An improved optimization-based simulation model is applied to simulate lifetime green manufacturing and the impacts of main institutional incentives and oxygen synergy on investment are analysed. Levelized cost of ammonia is estimated at around 820 USD/t which is about twice the present price. The operating rate ammonia price the electrical efficiency of electrolysers and the electricity price are found to be the key factors in green ammonia investment. Carbon pricing and value-added tax exemption exert obvious influences on the energy transition in China. A subsidy of approximately 450 USD/t will be required according to the present price; however this can be reduced by 100 USD/t through oxygen synergy. Compared to inter-regional power transmission green ammonia production shows both economic and environmental advantages. Therefore we propose an appropriate combination of both options to address renewable power curtailment and the integration of oxygen manufacturing into hydrogen production. We consider the findings and policy implications will contribute to addressing renewable power curtailment and boosting the hydrogen economy in China.
Recent Progress in Mixed-Matrix Membranes for Hydrogen Separation
Aug 2021
Publication
Membrane separation is a compelling technology for hydrogen separation. Among the different types of membranes used to date the mixed-matrix membranes (MMMs) are one of the most widely used approaches for enhancing separation performances and surpassing the Robeson upper bound limits for polymeric membranes. In this review we focus on the recent progress in MMMs for hydrogen separation. The discussion first starts with a background introduction of the current hydrogen generation technologies followed by a comparison between the membrane technology and other hydrogen purification technologies. Thereafter state-of-the-art MMMs comprising emerging filler materials that include zeolites metal-organic frameworks covalent organic frameworks and graphene-based materials are highlighted. The binary filler strategy which uses two filler materials to create synergistic enhancements in MMMs is also described. A critical evaluation on the performances of the MMMs is then considered in context before we conclude with our perspectives on how MMMs for hydrogen separation can advance moving forward.
Hydrogen Production Possibility using Mongolian Renewable Energy
Jan 2019
Publication
There is widespread popular support for using renewable energy particularly solar and wind energy which provide electricity without giving rise to any carbon dioxide emissions. Harnessing these for electricity depends on the cost and efficiency of the technology which is constantly improving thus reducing costs per peak kilowatt and per kWh. Utilizing solar and wind-generated electricity in a stand-alone system requires corresponding battery or other storage capacity. The possibility of large-scale use of hydrogen in the future as a transport fuel increases the potential for both renewables and base-load electricity supply.
Synthesizing the High Surface Area g-C3N4 for Greatly Enhanced Hydrogen Production
Jul 2021
Publication
Adjusting the structure of g-C3N4 to significantly enhance its photocatalytic activity has attracted considerable attention. Herein a novel sponge-like g-C3N4 with a porous structure is prepared from the annealing of protonated melamine under N2/H2 atmosphere (PH-CN). Compared to bulk g-C3N4 via calcination of melamine under ambient atmosphere (B-CN) PH-CN displays thinner nanosheets and a higher surface area (150.1 m2/g) which is a benefit for shortening the diffusion distance of photoinduced carriers providing more active sites and finally favoring the enhancement of the photocatalytic activity. Moreover it can be clearly observed from the UV-vis spectrum that PH-CN displays better performance for harvesting light compared to B-CN. Additionally the PH-CN is prepared with a larger band gap of 2.88 eV with the Fermi level and conduction band potential increased and valence band potential decreased which could promote the water redox reaction. The application experiment results show that the hydrogen evolution rate on PH-CN was nearly 10 times higher than that of B-CN which was roughly 4104 μmol h−1 g−1. The method shown in this work provides an effective approach to adjust the structure of g-C3N4with considerable photocatalytic hydrogen evolution activity.
Hydrogen Production by Fluidized Bed Reactors: A Quantitative Perspective Using the Supervised Machine Learning Approach
Jul 2021
Publication
The current hydrogen generation technologies especially biomass gasification using fluidized bed reactors (FBRs) were rigorously reviewed. There are involute operational parameters in a fluidized bed gasifier that determine the anticipated outcomes for hydrogen production purposes. However limited reviews are present that link these parametric conditions with the corresponding performances based on experimental data collection. Using the constructed artificial neural networks (ANNs) as the supervised machine learning algorithm for data training the operational parameters from 52 literature reports were utilized to perform both the qualitative and quantitative assessments of the performance such as the hydrogen yield (HY) hydrogen content (HC) and carbon conversion efficiency (CCE). Seven types of operational parameters including the steam-to-biomass ratio (SBR) equivalent ratio (ER) temperature particle size of the feedstock residence time lower heating value (LHV) and carbon content (CC) were closely investigated. Six binary parameters have been identified to be statistically significant to the performance parameters (hydrogen yield (HY)) hydrogen content (HC) and carbon conversion efficiency (CCE) by analysis of variance (ANOVA). The optimal operational conditions derived from the machine leaning were recommended according to the needs of the outcomes. This review may provide helpful insights for researchers to comprehensively consider the operational conditions in order to achieve high hydrogen production using fluidized bed reactors during biomass gasification.
Fuel Cells and Hydrogen Observatory Hydrogen Molecule Market Report
Sep 2021
Publication
The purpose of the hydrogen molecule market analysis is to track changes in the structure of hydrogen supply and demand in Europe. This report is mainly focused on presenting the current landscape - that will allow for future year-on-year comparisons in order to assess the progress Europe is making with regards to deployment of clean hydrogen production capacities as well as development of demand for clean hydrogen from emerging new hydrogen applications in the mobility sector or in industry. The following report summarizes the hydrogen molecule market landscape and contains data about hydrogen production and consumption in the EEA countries (EU countries together with Switzerland Norway Iceland and Liechtenstein). Hydrogen production capacity is presented by country and by technology whereas the hydrogen consumption data is presented by country and by end-use sector. The analysis undertaken for this report was completed using data available at the end of 2019. Hydrogen market (on both the demand and supply side) is dominated by ammonia and refining industries with three countries (DE NL PL) responsible for almost half hydrogen consumption. Today hydrogen is overwhelmingly produced by reforming of fossil fuels (mostly natural gas). Clean hydrogen production capacities are insignificant with blue hydrogen capacities at below 1% and green hydrogen production capacity below 0.1% of total.
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