Japan
TPR-XAFS Study for Hydrogen Recombination Reaction of Platinum Metal Nanoparticle Catalysts
Sep 2017
Publication
Proper management of hydrogen gas is very important for safety of nuclear power plants. Hydrogen removal system by hydrogen recombination reaction (water formation reaction) on a catalyst is one of the candidates for avoiding hydrogen explosion. We have observed in situ and time-resolved structure change of platinum metal nanoparticle catalyst during hydrogen recombination reaction by using simultaneous measurement of temperature-programmed reaction and X-ray absorption fine structure (TPR-XAFS). A poisoning effect by carbon monoxide on catalytic activity was focused. It was found that the start of hydrogen recombination reaction is closely connected with the occurrence of the decomposition of adsorbed carbon monoxide molecules and creation of surface oxide layer on platinum metal nanoparticles.
Outward Propagation Velocity and Acceleration Characteristics in Hydrogen-air Deflagration
Oct 2015
Publication
Propagation characteristics of hydrogen-air deflagration need to be understood for an accurate risk assessment. Especially flame propagation velocity is one of the most important factors. Propagation velocity of outwardly propagating flame has been estimated from burning velocity of a flat flame considering influence of thermal expansion at a flame front; however this conventional method is not enough to estimate an actual propagation velocity because flame propagation is accelerated owing to cellular flame front caused by intrinsic instability in hydrogen-air deflagration. Therefore it is important to understand the dynamic propagation characteristics of hydrogen-air deflagration. We performed explosion tests in a closed chamber which has 300 mm diameter windows and observed flame propagation phenomena by using Schlieren photography. In the explosion experiments hydrogen-air mixtures were ignited at atmospheric pressure and room temperature and in the range of equivalence ratio from 0.2 to 1.0. Analyzing the obtained Schlieren images flame radius and flame propagation velocity were measured. As the result cellular flame fronts formed and flame propagations of hydrogen–air mixture were accelerated at the all equivalence ratios. In the case of equivalent ratio φ = 0.2 a flame floated up and could not propagate downward because the influence of buoyancy exceeded a laminar burning velocity. Based upon these propagation characteristics a favorable estimation method of flame propagation velocity including influence of flame acceleration was proposed. Moreover the influence of intrinsic instability on propagation characteristics was elucidated.
Hydrogen Storage Mechanism in Sodium-Based Graphene Nanoflakes: A Density Functional Theory Study
Jan 2022
Publication
Carbon materials such as graphene nanoflakes carbon nanotubes and fullerene can be widely used to store hydrogen and doping these materials with lithium (Li) generally increases their H2 -storage densities. Unfortunately Li is expensive; therefore alternative metals are required to realize a hydrogen-based society. Sodium (Na) is an inexpensive element with chemical properties that are similar to those of lithium. In this study we used density functional theory to systematically investigate how hydrogen molecules interact with Na-doped graphene nanoflakes. A graphene nanoflake (GR) was modeled by a large polycyclic aromatic hydrocarbon composed of 37 benzene rings with GR-Na-(H2 )n and GR-Na+ -(H2 )n (n = 0–12) clusters used as hydrogen storage systems. Data obtained for the Na system were compared with those of the Li system. The single-H2 GR-Li and GR-Na systems (n = 1) exhibited binding energies (per H2 molecule) of 3.83 and 2.72 kcal/mol respectively revealing that the Li system has a high hydrogen-storage ability. This relationship is reversed from n = 4 onwards; the Na systems exhibited larger or similar binding energies for n = 4–12 than the Li-systems. The present study strongly suggests that Na can be used as an alternative metal to Li in H2 -storage applications. The H2 -storage mechanism in the Na system is also discussed based on the calculated results.
Fatigue and Fracture of High-hardenability Steels for Thick-walled Hydrogen Pressure Vessels
Sep 2017
Publication
Stationary pressure vessels for the storage of large volumes of gaseous hydrogen at high pressure (>70 MPa) are typically manufactured from Cr-Mo steels. These steels display hydrogen-enhanced fatigue crack growth but pressure vessels can be manufactured using defect-tolerant design methodologies. However storage volumes are limited by the wall thickness that can be reliably manufactured for quench and tempered Cr-Mo steels typically not more than 25-35 mm. High-hardenability steels can be manufactured with thicker walls which enables larger diameter pressure vessels and larger storage volumes. The goal of this study is to assess the fracture and fatigue response of high hardenability Ni-Cr-Mo pressure vessel steels for use in high-pressure hydrogen service at pressure in excess of 1000 bar. Standardized fatigue crack growth tests were performed in gaseous hydrogen at frequency of 1Hz and for R-ratios in the range of 0.1 to 0.7. Elastic-plastic fracture toughness measurements were also performed. The measured fatigue and fracture behavior is placed into the context of previous studies on fatigue and fracture of Cr-Mo steels for gaseous hydrogen.
Numerical Simulation on Low-speed Hydrogen Jet Diffusion
Oct 2015
Publication
The numerical simulation for the hydrogen jet experiments performed by Schefer et al. is conducted using the compressible multicomponent Navier-Stokes equations with the preconditioning method. The simulated results for the hydrogen jet agree with the theoretical results of Tollmien. As far as comparing with the experiments by Schefer et al. the concentration profiles along the radial direction agree with the present numerical results and that along the centerline also agree well with the experimental results after the data are normalized by the equivalent nozzle diameter. It is confirmed that the spread of the jet width from the jet exit to downstream is affected by the Kelvin-Helmholtz instability. It is also confirmed that the jet flow field is formed alternately by the high pressure region and the low pressure one to cause the jet flow fluctuation.
Reversible Ammonia-based and Liquid Organic Hydrogen Carriers for High-density Hydrogen Storage: Recent Progress
Feb 2019
Publication
Liquid hydrogen carriers are considered to be attractive hydrogen storage options because of their ease of integration into existing chemical transportation infrastructures when compared with liquid or compressed hydrogen. The development of such carriers forms part of the work of the International Energy Agency Task 32: Hydrogen-Based Energy Storage. Here we report the state-of-the-art for ammonia-based and liquid organic hydrogen carriers with a particular focus on the challenge of ensuring easily regenerable high-density hydrogen storage.
Effect of Carbon Monoxide on Polymer Electrolyte Fuel Cell Performance with a Hydrogen Circulation System
Feb 2022
Publication
The effect of carbon monoxide (CO) on the performance of polymer electrolyte fuel cells (PEFCs) with either a hydrogen circulation system or a hydrogen one-way pass system is investigated and compared. The voltage drop induced by adding 0.2 ppm of CO to the PEFC with the hydrogen circulation system was less than one-tenth of that observed in the PEFC with the hydrogen one-way pass system at 1000 mA cm–2 and a cell temperature of 60 °C. Gas analysis results showed that CO concentration in the hydrogen circulation system was lower than the initially supplied CO concentration. In the hydrogen circulation system permeated oxygen from the cathode should enhance CO oxidation. This should lead to decrease the CO concentration and mitigate the voltage drop in the hydrogen circulation system.
A Multiobjective Optimization of a Catalyst Distribution in a Methane/Steam Reforming Reactor Using a Genetic Algorithm
May 2020
Publication
The presented research focuses on an optimization design of a catalyst distribution inside a small-scale methane/steam reforming reactor. A genetic algorithm was used for the multiobjective optimization which included the search for an optimum of methane conversion rate and a minimum of the difference between highest and lowest temperatures in the reactor. For the sake of computational time the maximal number of the segment with different catalyst densities was set to be thirty in this study. During the entire optimization process every part of the reactor could be filled either with a catalyst material or non-catalytic metallic foam. In both cases the porosity and pore size was also specified. The impact of the porosity and pore size on the active reaction surface and permeability was incorporated using graph theory and three-dimensional digital material representation. Calculations start with the generation of a random set of possible reactors each with a different catalyst distribution. The algorithm calls reforming simulation over each of the reactors and after obtaining concentration and temperature fields the algorithms calculated fitness function. The properties of the best reactors are combined to generate a new population of solutions. The procedure is repeated and after meeting the coverage criteria the optimal catalyst distribution was proposed. The paper is summarized with the optimal catalyst distribution for the given size and working conditions of the system.
Ammonia as Effective Hydrogen Storage: A Review on Production, Storage and Utilization
Jun 2020
Publication
Ammonia is considered to be a potential medium for hydrogen storage facilitating CO2-free energy systems in the future. Its high volumetric hydrogen density low storage pressure and stability for long-term storage are among the beneficial characteristics of ammonia for hydrogen storage. Furthermore ammonia is also considered safe due to its high auto ignition temperature low condensation pressure and lower gas density than air. Ammonia can be produced from many different types of primary energy sources including renewables fossil fuels and surplus energy (especially surplus electricity from the grid). In the utilization site the energy from ammonia can be harvested directly as fuel or initially decomposed to hydrogen for many options of hydrogen utilization. This review describes several potential technologies in current conditions and in the future for ammonia production storage and utilization. Ammonia production includes the currently adopted Haber–Bosch electrochemical and thermochemical cycle processes. Furthermore in this study the utilization of ammonia is focused mainly on the possible direct utilization of ammonia due to its higher total energy efficiency covering the internal combustion engine combustion for gas turbines and the direct ammonia fuel cell. Ammonia decomposition is also described in order to give a glance at its progress and problems. Finally challenges and recommendations are also given toward the further development of the utilization of ammonia for hydrogen storage.
Materials for Hydrogen-based Energy Storage - Past, Recent Progress and Future Outlook
Dec 2019
Publication
Michael Hirscher,
Volodymyr A. Yartys,
Marcello Baricco,
José Bellosta von Colbe,
Didier Blanchard,
Robert C. Bowman Jr.,
Darren P. Broom,
Craig Buckley,
Fei Chang,
Ping Chen,
Young Whan Cho,
Jean-Claude Crivello,
Fermin Cuevas,
William I. F. David,
Petra E. de Jongh,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
Yaroslav Filinchuk,
George E. Froudakis,
David M. Grant,
Evan MacA. Gray,
Bjørn Christian Hauback,
Teng He,
Terry D. Humphries,
Torben R. Jensen,
Sangryun Kim,
Yoshitsugu Kojima,
Michel Latroche,
Hai-wen Li,
Mykhaylo V. Lototskyy,
Joshua W. Makepeace,
Kasper T. Møller,
Lubna Naheed,
Peter Ngene,
Dag Noreus,
Magnus Moe Nygård,
Shin-ichi Orimo,
Mark Paskevicius,
Luca Pasquini,
Dorthe B. Ravnsbæk,
M. Veronica Sofianos,
Terrence J. Udovic,
Tejs Vegge,
Gavin Walker,
Colin Webb,
Claudia Weidenthaler and
Claudia Zlotea
Globally the accelerating use of renewable energy sources enabled by increased efficiencies and reduced costs and driven by the need to mitigate the effects of climate change has significantly increased research in the areas of renewable energy production storage distribution and end-use. Central to this discussion is the use of hydrogen as a clean efficient energy vector for energy storage. This review by experts of Task 32 “Hydrogen-based Energy Storage” of the International Energy Agency Hydrogen TCP reports on the development over the last 6 years of hydrogen storage materials methods and techniques including electrochemical and thermal storage systems. An overview is given on the background to the various methods the current state of development and the future prospects. The following areas are covered; porous materials liquid hydrogen carriers complex hydrides intermetallic hydrides electro-chemical storage of energy thermal energy storage hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage
Economic Dispatch Model of Nuclear High-Temperature Reactor with Hydrogen Cogeneration in Electricity Market
Dec 2021
Publication
Hydrogen produced without carbon emissions could be a useful fuel as nations look to decarbonize their electricity transport and industry sectors. Using the iodine–sulfur (IS) cycle coupled with a nuclear heat source is one method for producing hydrogen without the use of fossil fuels. An economic dispatch model was developed for a nuclear-driven IS system to determine hydrogen sale prices that would make such a system profitable. The system studied is the HTTR GT/H2 a design for power and hydrogen cogeneration at the Japan Atomic Energy Agency’s High Temperature Engineering Test Reactor. This study focuses on the development of the economic model and the role that input data plays in the final calculated values. Using a historical price duration curve shows that the levelized cost of hydrogen (LCOH) or breakeven sale price of hydrogen would need to be 98.1 JPY/m3 or greater. Synthetic time histories were also used and found the LCOH to be 67.5 JPY/m3 . The price duration input was found to have a significant effect on the LCOH. As such great care should be used in these economic dispatch analyses to select reasonable input assumptions.
Drivers and Barriers to the Adoption of Fuel Cell Passenger Vehicles and Buses in Germany
Feb 2021
Publication
As policymakers and automotive stakeholders around the world seek to accelerate the electrification of road transport with hydrogen this study focuses on the experiences of Germany a world leader in fuel cell technology. Specifically it identifies and compares the drivers and barriers influencing the production and market penetration of privately-owned fuel cell electric passenger vehicles (FCEVs) and fuel cell electric buses (FCEBs) in public transit fleets. Using original data collected via a survey and 17 interviews we elicited the opinions of experts to examine opportunities and obstacles in Germany from four perspectives: (i) the supply of vehicles (ii) refuelling infrastructure (iii) demand for vehicles and (iv) cross-cutting institutional issues. Findings indicate that despite multiple drivers there are significant challenges hampering the growth of the hydrogen mobility market. Several are more pronounced in the passenger FCEV market. These include the supply and cost of production the lack of German automakers producing FCEVs the profitability and availability of refuelling stations and low demand for vehicles. In light of these findings we extract implications for international policymakers and future studies. This study provides a timely update on efforts to spur the deployment of hydrogen mobility in Germany and addresses the underrepresentation of studies examining both buses and passenger vehicles in tandem.
Strategies to Accelerate the Production and Diffusion of Fuel Cell Electric Vehicles: Experiences from California
Sep 2020
Publication
Fuel cell electric vehicles (FCEVs) can play a key role in accelerating the electrification of road transport. Specifically they offer longer driving ranges and shorter refuelling times relative to Battery Electric Vehicles (BEVs) while reducing needs for space-intensive public charging infrastructure. Although the maturity and market penetration of hydrogen is currently trailing batteries transport planners in several countries are looking to both technologies to reduce carbon emissions and air pollution. Home to the world’s largest on-road fleet of FCEVs California is one such jurisdiction. Experiences in California provide an ideal opportunity to address a gap in literature whereby barriers to FCEV diffusion are well understood but knowledge on actual strategies to overcome these has lacked. This study thus examines governance strategies in California to accelerate the production and diffusion of FCEVs key outcomes lessons learned and unresolved challenges. Evidence is sourced from 19 expert interviews and an examination of diverse documents. Strategies are examined from four perspectives: (i) supply-side (i.e. stimulation of vehicle production) (ii) infrastructure (i.e. construction of refuelling stations and hydrogen production) (iii) demand-side (i.e. stimulation of vehicle adoption) and (iv) institutional (i.e. cross-cutting measures to facilitate collaboration innovation and cost-reduction). Findings reveal a comprehensive mix of stringent regulation market and consumer incentives and public–private collaboration. However significant challenges remain for spurring the development of fuel cell transport in line with initial ambitions. Highlighting these provides important cues for public policy to accelerate the deployment of FCEVs and hydrogen in California and elsewhere.
Co-production of Hydrogen and Power from Black Liquor Via Supercritical Water Gasification, Chemical Looping and Power Generation
Mar 2019
Publication
An integrated system to harvest efficiently the energy from the waste of pulp mill industry which is black liquor (BL) is proposed and evaluated. The proposed system consists of the supercritical water gasification (SCWG) of BL syngas chemical looping and power generation. To minimize the exergy loss throughout the system and to optimize the energy efficiency process design and integration is conducted by employing the principles of exergy recovery and process integration methods. Hydrogen is set as the main output while power is produced by utilizing the heat generated throughout the process. Process simulation is conducted using a steady state process simulator Aspen Plus. Energy efficiency is defined into three categories: hydrogen production efficiency power generation efficiency and total energy efficiency. From process simulation both of the integrated systems show very high total energy efficiency of about 73%.
Feasibility Study of "CO2 Free Hydrogen Chain" Utilizing Australian Brown Coal Linked with CCS
Nov 2012
Publication
We had investigated feasible measures to reduce CO2 emission and came to conclusion that introduction of new fuel such as hydrogen with near zero CO2 emission is required for achieving Japan’s commitment of 80% CO2 reduction by 2050. Under this background we are proposing and aiming to realize “CO2 free hydrogen chain” utilizing Australian brown coal linked with CCS. In this chain hydrogen produced from brown coal is liquefied and transported to Japan by liquid hydrogen carrier. We have conducted feasibility study of commercial scale “CO2 free hydrogen chain” whose result shows the chain is technically and economically feasible.
Reduction in Greenhouse Gas and Other Emissions from Ship Engines: Current Trends and Future Options
Nov 2022
Publication
The impact of ship emission reductions can be maximised by considering climate health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships routes and regions. Carbon-neutral fuels including low-carbon and carbon-negative fuels from biogenic or non-biogenic origin (biomass waste renewable hydrogen) could resemble current marine fuels (diesel-type methane and methanol). The carbon-neutrality of fuels depends on their Well-to-Wake (WtW) emissions of greenhouse gases (GHG) including carbon dioxide (CO2) methane (CH4) and nitrous oxide emissions (N2O). Additionally non-gaseous black carbon (BC) emissions have high global warming potential (GWP). Exhaust emissions which are harmful to health or the environment need to be equally removed using emission control achieved by fuel engine or exhaust aftertreatment technologies. Harmful emission species include nitrogen oxides (NOx) sulphur oxides (SOx) ammonia (NH3) formaldehyde particle mass (PM) and number emissions (PN). Particles may carry polyaromatic hydrocarbons (PAHs) and heavy metals which cause serious adverse health issues. Carbon-neutral fuels are typically sulphur-free enabling negligible SOx emissions and efficient exhaust aftertreatment technologies such as particle filtration. The combinations of carbon-neutral drop-in fuels and efficient emission control technologies would enable (near-)zero-emission shipping and these could be adaptable in the short- to mid-term. Substantial savings in external costs on society caused by ship emissions give arguments for regulations policies and investments needed to support this development.
Influence of Renewable Energy Power Fluctuations on Water Electrolysis for Green Hydrogen Production
Nov 2022
Publication
The development of renewable energy technologies is essential to achieve carbon neutrality. Hydrogen can be stably stored and transported in large quantities to maximize power utilization. Detailed understanding of the characteristics and operating methods of water electrolysis technologies in which naturally intermittent fluctuating power is used directly is required for green hydrogen production because fluctuating power-driven water electrolysis processes significantly differ from industrial water electrolysis processes driven by steady grid power. Thus it is necessary to overcome several issues related to the direct use of fluctuating power. This article reviews the characteristics of fluctuating power and its generation as well as the current status and issues related to the operation conditions water electrolyzer configuration system requirements stack/catalyst durability and degradation mechanisms under the direct use of fluctuating power sources. It also provides an accelerated degradation test protocol method for fair catalyst performance comparison and share of effective design directions. Finally it discusses potential challenges and recommendations for further improvements in water electrolyzer components and systems suitable for practical use suggesting that a breakthrough could be realized toward the achievement of a sustainable hydrogen-based society.
A Theoretical Study Using the Multiphase Numerical Simulation Technique for Effective Use of H2 as Blast Furnaces Fuel
Jun 2017
Publication
We present a numerical simulation procedure for analyzing hydrogen oxygen and carbon dioxide gases injections mixed with pulverized coals within the tuyeres of blast furnaces. Effective use of H2 rich gas is highly attractive into the steelmaking blastfurnace considering the possibility of increasing the productivity and decreasing the specific emissions of carbon dioxide becoming the process less intensive in carbon utilization. However the mixed gas and coal injection is a complex technology since significant changes on the inner temperature and gas flow patterns are expected beyond to their effects on the chemical reactions and heat exchanges. Focusing on the evaluation of inner furnace status under such complex operation a comprehensive mathematical model has been developed using the multi interaction multiple phase theory. The BF considered as a multiphase reactor treats the lump solids (sinter small coke pellets granular coke and iron ores) gas liquids metal and slag and pulverized coal phases. The governing conservation equations are formulated for momentum mass chemical species and energy and simultaneously discretized using the numerical method of finite volumes. We verified the model with a reference operational condition using pulverized coal of 215 kg per ton of hot metal (kg thm−1). Thus combined injections of varying concentrations of gaseous fuels with H2 O2 and CO2 are simulated with 220 kg thm−1 and 250 kg thm−1 coals injection. Theoretical analysis showed that stable operations conditions could be achieved with productivity increase of 60%. Finally we demonstrated that the net carbon utilization per ton of hot metal decreased 12%.
Potential Domestic Energy System Vulnerabilities from Major Exports of Green Hydrogen: A Case Study of Australia
Aug 2023
Publication
Australia has clear aspirations to become a major global exporter of hydrogen as a replacement for fossil fuels and as part of the drive to reduce CO2 emissions as set out in the National Hydrogen Strategy released in 2019 jointly by the federal and state governments. In 2021 the Australian Energy Market Operator specified a grid forecast scenario for the first time entitled “hydrogen superpower”. Not only does Australia hope to capitalise on the emerging demand for zero-carbon hydrogen in places like Japan and South Korea by establishing a new export industry but it also needs to mitigate the built-in carbon risk of its export revenue from coal and LNG as major customers such as Japan and South Korea move to decarbonise their energy systems. This places hydrogen at the nexus of energy climate change mitigation and economic growth with implications for energy security. Much of the published literature on this topic concentrates on the details of what being a major hydrogen exporter will look like and what steps will need to be taken to achieve it. However there appears to be a gap in the study of the implications for Australia’s domestic energy system in terms of energy security and export economic vulnerability. The objective of this paper is to develop a conceptual framework for the implications of becoming a major hydrogen exporter on Australia’s energy system. Various green hydrogen export scenarios for Australia were compared and the most recent and comprehensive was selected as the basis for further examination for domestic energy system impacts. In this scenario 248.5 GW of new renewable electricity generation capacity was estimated to be required by 2050 to produce the additional 867 TWh required for an electrolyser output of 2088 PJ of green hydrogen for export which will comprise 55.9% of Australia’s total electricity demand at that time. The characteristics of comparative export-oriented resources and their interactions with the domestic economy and energy system are then examined through the lens of the resource curse hypothesis and the LNG and aluminium industries. These existing resource export frameworks are reviewed for applicability of specific factors to export-oriented green hydrogen production with applicable factors then compiled into a novel conceptual framework for exporter domestic implications from large-scale exports of green hydrogen. The green hydrogen export superpower (2050) scenario is then quantitatively assessed using the established indicators for energy exporter vulnerability and domestic energy security comparing it to Australia’s 2019 energy exports profile. This assessment finds that in almost all factors exporter vulnerability is reduced and domestic energy security is enhanced by the transition from fossil fuel exports to green hydrogen with the exception of an increase in exposure of the domestic energy system to international market forces.
Potential Renewable Hydrogen from Curtailed Electricity to Decarbonize ASEAN’s Emissions: Policy Implications
Dec 2020
Publication
The power generation mix of the Association of Southeast Asian Nations (ASEAN) is dominated by fossil fuels which accounted for almost 80% in 2017 and are expected to account for 82% in 2050 if the region does not transition to cleaner energy systems. Solar and wind power are the most abundant energy resources but contribute negligibly to the power mix. Investors in solar or wind farms face high risks from electricity curtailment if surplus electricity is not used. Employing the policy scenario analysis of the energy outlook modelling results this paper examines the potential scalability of renewable hydrogen production from curtailed electricity in scenarios of high share of variable renewable energy in the power generation mix. The study found that ASEAN has high potential in developing renewable hydrogen production from curtailed electricity. The study further found that the falling cost of renewable hydrogen production could be a game changer to upscaling the large-scale hydrogen production in ASEAN through policy support. The results implied a future role of renewable hydrogen in energy transition to decarbonize ASEAN’s emissions.
Science and Technology of Ammonia Combustion
Nov 2018
Publication
This paper focuses on the potential use of ammonia as a carbon-free fuel and covers recent advances in the development of ammonia combustion technology and its underlying chemistry. Fulfilling the COP21 Paris Agreement requires the de-carbonization of energy generation through utilization of carbon-neutral and overall carbon-free fuels produced from renewable sources. Hydrogen is one of such fuels which is a potential energy carrier for reducing greenhouse-gas emissions. However its shipment for long distances and storage for long times present challenges. Ammonia on the other hand comprises 17.8% of hydrogen by mass and can be produced from renewable hydrogen and nitrogen separated from air. Furthermore thermal properties of ammonia are similar to those of propane in terms of boiling temperature and condensation pressure making it attractive as a hydrogen and energy carrier. Ammonia has been produced and utilized for the past 100 years as a fertilizer chemical raw material and refrigerant. Ammonia can be used as a fuel but there are several challenges in ammonia combustion such as low flammability high NOx emission and low radiation intensity. Overcoming these challenges requires further research into ammonia flame dynamics and chemistry. This paper discusses recent successful applications of ammonia fuel in gas turbines co-fired with pulverize coal and in industrial furnaces. These applications have been implemented under the Japanese ‘Cross-ministerial Strategic Innovation Promotion Program (SIP): Energy Carriers’. In addition fundamental aspects of ammonia combustion are discussed including characteristics of laminar premixed flames counterflow twin-flames and turbulent premixed flames stabilized by a nozzle burner at high pressure. Furthermore this paper discusses details of the chemistry of ammonia combustion related to NOx production processes for reducing NOx and validation of several ammonia oxidation kinetics models. Finally LES results for a gas-turbine-like swirl-burner are presented for the purpose of developing low-NOx single-fuelled ammonia gas turbine combustors.
Design of an Architectural Element Generating Hydrogen Energy by Photosynthesis—Model Case of the Roof and Window
Jun 2022
Publication
As is well known the realization of a zero-waste society is strongly desired in a sustainable society. In particular architectural elements that provide an energy-neutral living environment are attractive. This article presents the novel environmentally friendly architectural elements that generate hydrogen energy by the photosystem II (PSII) solution extracted from waste vegetables. In the present work as an architectural element the window (PSII window panel) and roof (PSII roof panel) were fabricated by injecting a PSII solution into a transparent double-layer panel and the aging properties of the power generation and the appearance of these PSII panels are investigated. It was found that the PSII roof can generate energy for 18 days under the sun shining and can actually drive the electronic device. In addition the PSII window for which light intensity is weaker than that for the PSII roof can maintain power generation for 40 days. These results indicate that the PSII roof and PSII window become the architectural elements generating energy although the lifespan depends on the total light intensity. Furthermore as an additional advantage the roof and window panels composed of the semitransparent PSII panel yield an interior space with the natural color of the leaf which gradually changes over time from green to yellow. Further it was also found that the thermal fluctuation of the PSII window is smaller than that of the typical glass window. These results indicate that the roof and window panels composed of the PSII solution extracted from waste vegetables can be used as the actual architectural elements to produce not only the electrical energy but also the beautiful transparent natural green/yellow spaces.
Effects of Thermomechanical Processing on Hydrogen Embrittlement Properties of Ultrahigh-Strength TRIP-Aided Bainitic Ferrite Steels
Jan 2022
Publication
The effects of thermomechanical processing on the microstructure and hydrogen embrittlement properties of ultrahigh-strength low-alloy transformation-induced plasticity (TRIP)-aided bainitic ferrite (TBF) steels were investigated to apply to automobile forging parts such as engine and drivetrain parts. The hydrogen embrittlement properties were evaluated by conducting conventional tensile tests after hydrogen charging and constant load four-point bending tests with hydrogen charging. The 0.4 mass%C-TBF steel achieved refinement of the microstructure improved retained austenite characteristics and strengthening owing to thermomechanical processing. This might be attributed to dynamic and static recrystallizations during thermomechanical processing in TBF steels. Moreover the hydrogen embrittlement resistances were improved by the thermomechanical processing in TBF steels. This might be caused by the refinement of the microstructure an increase in the stability of the retained austenite and low hydrogen absorption of the thermomechanically processed TBF steels.
Observation of the Hydrogen Dispersion by Using Raman Scattering Measurement and Increase of Measurable Distance
Sep 2017
Publication
Preparing for the arrival of the hydrogen society it is necessary to develop suitable sensors to use hydrogen safely. There are many methods to know the hydrogen concentration by using conventional sensors but it is difficult to know the behavior of hydrogen gas from long distance. This study measured hydrogen dispersion by using Raman scattering light. Generally some delays occur when using conventional sensors but there are almost no delays by using the new Raman sensor. In the experiments 6mm & 1mm diameter holes are used as a spout nozzle to change initial velocities. To ensure the result a special sheets are used which turns transparent when it detected hydrogen and visualized the hydrogen behaviour. As a result the behaviour of the hydrogen gas in the small container was observed. In addition measurable distance is increased by the improvement of the device.
Operation of Metal Hydride Hydrogen Storage Systems for Hydrogen Compression Using Solar Thermal Energy
Mar 2016
Publication
By using a newly constructed bench-scale hydrogen energy system with renewable energy ‘Pure Hydrogen Energy System’ the present study demonstrates the operations of a metal hydride (MH) tank for hydrogen compression as implemented through the use solar thermal energy. Solar thermal energy is used to generate hot water as a heat source of the MH tank. Thus 70 kg of LaNi5 one of the most typical alloys used for hydrogen storage was placed in the MH tank. We present low and high hydrogen flow rate operations. Then the operations under winter conditions are discussed along with numerical simulations conducted from the thermal point of view. Results show that a large amount of heat (>100 MJ) is generated and the MH hydrogen compression is available.
The Roles of Nuclear Energy in Hydrogen Production
Dec 2021
Publication
Fossil resources are unevenly distributed on the earth and are finite primary energy which is widely used in the fields of industry transportation and power generation etc.<br/>Primary energies that can replace fossil resources include renewable energy and nuclear energy. Hydrogen has the potential to be secondary energy that can be widely used in industry for various purposes. Nuclear energy can be used for producing hydrogen; it is becoming more important to convert this primary energies into hydrogen. This paper describes the roles of nuclear energy as a primary energy in hydrogen production from the viewpoint of the basics of energy form conversion.
Effect of Defects and Hydrogen on the Fatigue Limit of Ni-based Superalloy 718
Dec 2019
Publication
Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular the fatigue strength susceptibility to defects varied significantly according to the type of microstructural morphology i.e. a smaller grain size made the alloy more vulnerable to defects. The fatigue limit as a small-crack threshold was successfully predicted using the √area parameter model. Depending on the size of defects the fatigue limit was calculated in relation to three phases: (i) harmless-defect regime (ii) small-crack regime and (iii) large-crack regime. Such a classification enabled comprehensive fatigue limit evaluation in a wide array of defects taking into consideration (a) the defect size over a range of small crack and large crack and (b) the characteristics of the matrix represented by grain size and hardness. In addition the effect of defects and hydrogen on fatigue strength will be comprehensively discussed based on a series of experimental results.
Effect of Flow Speed on Ignition Characteristics of Hydrogen/air Mixtures
Sep 2021
Publication
A fuel cell vehicle has a purging system for exhausting contaminated hydrogen gas. Notwithstanding the allowable hydrogen emissions levels in the purging system are regulated by the GTR a further research on the safety requirement of emissions concentrations is therefore needed for the vehicle design into a more rational system. In the present study the effects of flow speed concentration humidity on ignition characteristics of hydrogen/air mixtures were experimentally investigated. The results demonstrate that the value of Lower Flammable Limit increased with an increase in the velocity of hydrogen/air mixtures and slightly increased with a decrease in oxygen concentration.
Quantitive Risk Assessment of the Model Representing Latest Japanese Hydrogen Refuelling Stations
Sep 2021
Publication
Current safety codes and technical standards related to Japanese hydrogen refueling stations (HRSs) have been established based on qualitative risk assessment and quantitative effectiveness validation of safety measures for more than ten years. In the last decade there has been significant development in the technologies and significant increment in operational experience related to HRSs. We performed a quantitative risk assessment (QRA) of the HRS model representing Japanese HRSs with the latest information in the previous study. The QRA results were obtained by summing risk contours derived from each process unit. They showed that the risk contours of 10-3 and 10-4 per year were confined within the HRS boundaries whereas those of 10-5 and 10-6 per year are still present outside the HRS boundaries. Therefore we analyzed the summation of risk contours derived from each unit and identified the largest risk scenarios outside the station. The HRS model in the previous study did not consider fire and blast protection walls which could reduce the risks outside the station. Therefore we conducted a detailed risk analysis of the identified scenarios using 3D structure modeling. The heat radiation and temperature rise of jet fire scenarios that pose the greatest risk to the physical surroundings in the HRS model were estimated in detail based on computational fluid dynamics with 3D structures including fire protection walls. Results show that the risks spreading outside the north- west- and east-side station boundaries are expected to be acceptable by incorporating the fire protection wall into the Japanese HRS model.
An Experimental Study of Propagating Spherical Flames in Unconfined Hydrogen-oxygen Explosions
Sep 2021
Publication
The study to understand the flame propagation behaviors of hydrogen-oxygen explosions is required to make a precise risk assessment. Moreover although research has investigated the propagating spherical flames in unconfined hydrogen-air explosions no study to date has examined the hydrogen-oxygen explosions. The spherical flame propagation in unconfined hydrogen-oxygen explosions have been investigated using a soap bubble method. In the present experiments hydrogen-oxygen mixtures were filled in a 10 cm diameter soap bubble and ignited by an electric spark at the center. The flame propagation behaviors were measured by a high-speed Schlieren photography. The laminar burning velocities and critical flame radii for the onset of flame acceleration in unconfined hydrogen-oxygen explosions were estimated. Results demonstrated that the laminar burning velocities of hydrogenoxygen mixtures were much faster than those of hydrogen-air mixtures. In addition the shift value of maximum laminar burning velocity for hydrogen-oxygen mixtures towards a leaner equivalence ratio is observed. The experimental flame speeds for all experiments were increased owing to diffusionalthermal and Darrieus-Landau instabilities although the measured flame radii were small. The critical flame radius corresponding to the onset of flame acceleration decreased with the decrease in equivalence ratio.
Numerical Study of Hydrogen Addition Effects on Aluminum Particle Combustion
Sep 2021
Publication
In this study the combustion of submicron-sized Al particles in air was studied numerically with a particular focus on the effect of hydrogen addition. Oxidation of the Al particles and the interaction with hydrogen-related intermediates were considered by regarding them as liquid-phase molecules initially. Zero- and One-dimensional numerical simulations were then carried out to investigate the effect of the hydrogen addition on fundamental combustion characteristics of the Al flame by calculating properties such as ignition delay time and flame speed. Our attention was paid to how the hydrogen chemistry is coupled with the Al oxidation process. Numerical results show that the hydrogen addition generally reduces the reactivity of Al such that the flame speed and temperature decrease while it can greatly shorten ignition delay times of the Al flame depending on initial temperatures.
Significance of Hydrogen as Economic and Environmentally Friendly Fuel
Nov 2021
Publication
The major demand of energy in today’s world is fulfilled by the fossil fuels which are not renewable in nature and can no longer be used once exhausted. In the beginning of the 21st century the limitation of the fossil fuels continually growing energy demand and growing impact of greenhouse gas emissions on the environment were identified as the major challenges with current energy infrastructure all over the world. The energy obtained from fossil fuel is cheap due to its established infrastructure; however these possess serious issues as mentioned above and cause bad environmental impact. Therefore renewable energy resources are looked to as contenders which may fulfil most energy requirements. Among them hydrogen is considered as the most environmentally friendly fuel. Hydrogen is clean sustainable fuel and it has promise as a future energy carrier. It also has the ability to substitute the present energy infrastructure which is based on fossil fuel. This is seen and projected as a solution for the above-mentioned problems including rise in global temperature and environmental degradation. Environmental and economic aspects are the important factors to be considered to establish hydrogen infrastructure. This article describes the various aspects of hydrogen including production storage and applications with a focus on fuel cell based electric vehicles. Their environmental as well as economic aspects are also discussed herein.
Novel Ways for Hydrogen Production Based on Methane Steam and Dry Reforming Integrated with Carbon Capture
Sep 2022
Publication
The combination of methane steam reforming technology and CCS (Carbon Capture and Storage) technology has great potential to reduce carbon emissions in the process of hydrogen production. Different from the traditional idea of capturing CO2 (Carbon Dioxide) in the exhaust gas with high work consumption this study simultaneously focuses on CO2 separation from fuel gas and recycling. A new hydrogen production system is developed by methane steam reforming coupled with carbon capture. Separated and captured high-purity carbon dioxide could be recycled for methane dry reforming; on this basis a new methane-dry-reforming-driven hydrogen production system with a carbon dioxide reinjection unit is innovatively proposed. In this study the energy flow and irreversible loss in the two newly developed systems are analyzed in detail through energy and exergy balance analysis. The advantages are explored from the perspective of hydrogen production rate natural gas consumption and work consumption. In addition in consideration of the integrated performance an optimal design analysis was conducted. In terms of hydrogen production the new system based on dry reforming is better with an advantage of 2.41%; however it is worth noting that the comprehensive thermal performance of the new steam reforming system is better reaching 10.95%. This study provides new ideas for hydrogen production from a low carbon emission perspective and also offers a new direction for future distributed energy system integration.
Design of a Hydrogen Production System Considering Energy Consumption, Water Consumption, CO2 Emissions and Cost
Oct 2022
Publication
CO2 emissions associated with hydrogen production can be reduced replacing steam methane reforming with electrolysis using renewable electricity with a trade-off of increasing energy consumption water consumption and cost. In this research a linear programming optimization model of a hydrogen production system that considers simultaneously energy consumption water consumption CO2 emissions and cost on a cradle-to-gate basis was developed. The model was used to evaluate the impact of CO2 intensity on the optimum design of a hydrogen production system for Japan considering different stakeholders’ priorities. Hydrogen is produced using steam methane reforming and electrolysis. Electricity sources include grid wind solar photovoltaic geothermal and hydro. Independent of the stakeholders’ priorities steam methane reforming dominates hydrogen production for cradle-to-gate CO2 intensities larger than 9 kg CO2/kg H2 while electrolysis using renewable electricity dominates for lower cradle-to-gate CO2 intensities. Reducing the cradle-to-gate CO2 intensity increases energy consumption water consumption and specific cost of hydrogen production. For a cradle-to-gate CO2 intensity of 0 kg CO2/kg H2 the specific cost of hydrogen production varies between 8.81 and 13.6 USD/kg H2; higher than the specific cost of hydrogen production targeted by the Japanese government in 2030 of 30 JPY/Nm3 3.19 USD/kg H2.
A Historical Analysis of Hydrogen Economy Research, Development, and Expectations, 1972 to 2020
Jan 2023
Publication
Global climate change concerns have pushed international governmental actions to reduce greenhouse gas emissions by adopting cleaner technologies hoping to transition to a more sustainable society. The hydrogen economy is one potential long-term option for enabling deep decarbonization for the future energy landscape. Progress towards an operating hydrogen economy is discouragingly slow despite global efforts to accelerate it. There are major mismatches between the present situation surrounding the hydrogen economy and previous proposed milestones that are far from being reached. The overall aim of this study is to understand whether there has been significant real progress in the achievement of a hydrogen economy or whether the current interest is overly exaggerated (hype). This study uses bibliometric analysis and content analysis to historically map the hydrogen economy’s development from 1972 to 2020 by quantifying and analyzing three sets of interconnected data. Findings indicate that interest in the hydrogen economy has significantly progressed over the past five decades based on the growing numbers of academic publications media coverage and projects. However various endogenous and exogenous factors have influenced the development of the hydrogen economy and created hype at different points in time. The consolidated results explore the changing trends and how specific events or actors have influenced the development of the hydrogen economy with their agendas the emergence of hype cycles and the expectations of a future hydrogen economy.
Solid-State Hydrogen Fuel by PSII–Chitin Composite and Application to Biofuel Cell
Dec 2021
Publication
Biomaterials attract a lot of attention as next-generation materials. Especially in the energy field fuel cells based on biomaterials can further develop clean next-generation energy and are focused on with great interest. In this study solid-state hydrogen fuel (PSII–chitin composite) composed of the photosystem II (PSII) and hydrated chitin composite was successfully created. Moreover a biofuel cell consisting of the electrolyte of chitin and the hydrogen fuel using the PSII– chitin composite was fabricated and its characteristic feature was investigated. We found that proton conductivity in the PSII–chitin composite increases by light irradiation. This result indicates that protons generate in the PSII–chitin composite by light irradiation. It was also found that the biofuel cell using the PSII–chitin composite hydrogen fuel and the chitin electrolyte exhibits the maximum power density of 0.19 mW/cm2 . In addition this biofuel cell can drive an LED lamp. These results indicate that the solid-state biofuel cell based on the bioelectrolyte “chitin” and biofuel “the PSII–chitin composite” can be realized. This novel solid-state fuel cell will be helpful to the fabrication of next-generation energy.
Environmental and Socio-Economic Analysis of Naphtha Reforming Hydrogen Energy Using Input-Output Tables: A Case Study from Japan
Aug 2017
Publication
Comprehensive risk assessment across multiple fields is required to assess the potential utility of hydrogen energy technology. In this research we analyzed environmental and socio-economic effects during the entire life cycle of a hydrogen energy system using input-output tables. The target system included hydrogen production by naphtha reforming transportation to hydrogen stations and FCV (Fuel Cell Vehicle) refilling. The results indicated that 31% 44% and 9% of the production employment and greenhouse gas (GHG) emission effects respectively during the manufacturing and construction stages were temporary. During the continuous operation and maintenance stages these values were found to be 69% 56% and 91% respectively. The effect of naphtha reforming was dominant in GHG emissions and the effect of electrical power input on the entire system was significant. Production and employment had notable effects in both the direct and indirect sectors including manufacturing (pumps compressors and chemical machinery) and services (equipment maintenance and trade). This study used data to introduce a life cycle perspective to environmental and socio-economic analysis of hydrogen energy systems and the results will contribute to their comprehensive risk assessment in the future.
Solar Hydrogen Fuel Generation from Wastewater—Beyond Photoelectrochemical Water Splitting: A Perspective
Oct 2022
Publication
Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials however limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however their commercial potential still remains unexploited due to the high hydrogen generation costs. Novel PEC-based simultaneous generation of green hydrogen and wastewater treatment/high-value product production is therefore seen as an alternative to conventional water splitting. Interestingly the organic/inorganic pollutants in wastewater and biomass favourably act as electron donors and facilitate the dual-functional process of recovering green hydrogen while oxidising the organic matter. The generation of green hydrogen through the dual-functional PEC process opens up opportunities for a “circular economy”. It further enables the end-of-life commodities to be reused recycled and resourced for a better life-cycle design while being economically viable for commercialisation. This review brings together and critically analyses the recent trends towards simultaneous wastewater treatment/biomass reforming while generating hydrogen gas by employing the PEC technology. We have briefly discussed the technical challenges associated with the tandem PEC process new avenues techno-economic feasibility and future directions towards achieving net neutrality.
Techno-Economic Analysis of Solar Thermal Hydrogen Production in the United Arab Emirates
Oct 2022
Publication
Solar thermal technology can provide the United Arab Emirates and the Middle East region with abundant clean electricity to mitigate the rising levels of carbon dioxide and satisfy future demand. Hydrogen can play a key role in the large-scale application of solar thermal technologies such as concentrated solar plants in the region by storing the surplus electricity and exporting it to needed countries for profit placing the Middle East and the United Arab Emirates as major future green hydrogen suppliers. However a hydrogen supply chain comparison between hydrogen from CSP and other renewable under the UAE’s technical and economic conditions for hydrogen export is yet to be fully considered. Therefore in this study we provide a techno-economic analysis for well-to-ship solar hydrogen supply chain that compares CSP and PV technologies with a solid oxide water electrolyzer for hydrogen production assuming four different hydrogen delivery pathways based on the location of electrolyzer and source of electricity assuming the SOEC can be coupled to the CSP plant when placed at the same site or provided with electric heaters when placed at PV plant site or port sites. The results show that the PV plant achieves a lower levelized cost of electricity than that of the CSP plant with 5.08 ¢/kWh and 8.6 ¢/kWh respectively. Hydrogen production results show that the scenario where SOEC is coupled to the CSP plant is the most competitive scenario as it achieves the payback period in the shortest period compared to the other scenarios and also provides higher revenues and a cheaper LCOH of 7.85 $/kgH2.
Thermodynamic Analysis of Hydrogen Utilization as Alternative Fuel in Cement Production
Jul 2022
Publication
Growing attention to the environmental aspect has urged the effort to reduce CO2 emission as one of the greenhouse gases. The cement industry is one of the biggest CO2 emitters in this world. Alternative fuel is one of the challenging issues in cement production due to the limited fossil fuel resources and environmental concerns. Meanwhile hydrogen (H2) has been reported as a promising non-carbon fuel with ammonia (NH3) as the main candidate for chemical storage methods. In this work an integrated system of cement production with an alternative H2-based fuel is proposed consisting of the dehydrogenation process of NH3 and the H2 combustion to provide the required thermal energy for clinker production. Different catalysts are employed and evaluated to analyze the specific energy input (SEI). The result shows that the conversion rate strongly determines the SEI with minimum SEI (3829.8 MJ t-clinker-1 ) achieved by Ni-Pt-based catalyst at a reaction temperature of 600 ºC. Compared to the conventional fuel of coal the H2-based integrated cement production system shows a significant decrease of 44% in CO2 emission due to carbon-free combustion using H2 as the fuel. The current study on the proposed integrated system of H2-based cement production also provides an initial thermodynamic analysis and basic observation for the adoption of non-carbon-based H2 including the storage system of NH3 in the cement production process.
CFD Simulation of Pressure Reduction Inside Large-scale Liquefied Hydrogen Tank
Sep 2021
Publication
Building the international hydrogen supply chain requires the large-scale liquefied hydrogen(LH2) carrier. During shipping LH2 with LH2 Carrier the tank is pressurized by LH2 evaporation due to heat ingress from outside. Before unloading LH2 at the receiving terminal reducing the tank pressure is essential for the safe tank operation. However pressure reduction might cause flashing leading to rapid vaporization of liquefied hydrogen liquid leakage. Moreover it was considered that pressure recovery phenomenon which was not preferred in terms of tank pressure management occurred at the beginning of pressure reduction. Hence the purpose of our research is to clarify the phenomenon inside the cargo tank during pressure reduction. The CFD analysis of the pressure reduction phenomenon was conducted with the VOF based in-house CFD code utilizing the C-CUP scheme combined with the hybrid Level Set and MARS method. In our previous research the pressure reduction experiments with the 30 m³ LH2 tank were simulated and the results showed that the pressure recovery was caused by the boiling delay and the tank pressure followed the saturation pressure after the liquid was fully stirred. In this paper the results were re-evaluated in terms of temperature. While pressure reduction was dominant the temperature of vapor-liquid interface decreased. Once the boiling bubble stirred the interface its temperature reached the saturation temperature after pressure recovery occurred. Moreover it was found that the liquid temperature during pressure reduction could not be measured because of the boiling from the wall of the thermometer. The CFD analysis on pressure reduction of 1250 m³ tank for the LH2 Carrier was also very could occur in the case of the 1250 m³ tank in a certain condition. These results provide new insight into the development of the LH2 carrier.
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.
Techno-Economic Analysis of a Novel Hydrogen-Based Hybrid Renewable Energy System for Both Grid-Tied and Off-Grid Power Supply in Japan: The Case of Fukushima Prefecture
Jun 2020
Publication
After the Great East Japan Earthquake energy security and vulnerability have become critical issues facing the Japanese energy system. The integration of renewable energy sources to meet specific regional energy demand is a promising scenario to overcome these challenges. To this aim this paper proposes a novel hydrogen-based hybrid renewable energy system (HRES) in which hydrogen fuel can be produced using both the methods of solar electrolysis and supercritical water gasification (SCWG) of biomass feedstock. The produced hydrogen is considered to function as an energy storage medium by storing renewable energy until the fuel cell converts it to electricity. The proposed HRES is used to meet the electricity demand load requirements for a typical household in a selected residential area located in Shinchi-machi in Fukuoka prefecture Japan. The techno-economic assessment of deploying the proposed systems was conducted using an integrated simulation-optimization modeling framework considering two scenarios: (1) minimization of the total cost of the system in an off-grid mode and (2) maximization of the total profit obtained from using renewable electricity and selling surplus solar electricity to the grid considering the feed-in-tariff (FiT) scheme in a grid-tied mode. As indicated by the model results the proposed HRES can generate about 47.3 MWh of electricity in all scenarios which is needed to meet the external load requirement in the selected study area. The levelized cost of energy (LCOE) of the system in scenarios 1 and 2 was estimated at 55.92 JPY/kWh and 56.47 JPY/kWh respectively
Novel Biofuel Cell Using Hydrogen Generation of Photosynthesis
Nov 2020
Publication
Energies based on biomaterials attract a lot of interest as next-generation energy because biomaterials are environmentally friendly materials and abundant in nature. Fuel cells are also known as the clean and important next-generation source of energy. In the present study to develop the fuel cell based on biomaterials a novel biofuel cell which consists of collagen electrolyte and the hydrogen fuel generated from photochemical system II (PSII) in photosynthesis has been fabricated and its property has been investigated. It was found that the PSII solution in which PSII was extracted from the thylakoid membrane using a surfactant generates hydrogen by the irradiation of light. The typical hydrogen-generating rate is approximately 7.41 × 1014 molecules/s for the light intensity of 0.5 mW/cm2 for the PSII solution of 5 mL. The biofuel cell using the PSII solution as the fuel exhibited approximately 0.12 mW/cm2 . This result indicates that the fuel cell using the collagen electrolyte and the hydrogen fuel generated from PSII solution becomes the new type of biofuel cell and will lead to the development of the next-generation energy
The Role of Hydrogen in Achieving Long Term Japanese Energy System Goals
Sep 2020
Publication
This research qualitatively reviews literature regarding energy system modeling in Japan specific to the future hydrogen economy leveraging quantitative model outcomes to establish the potential future deployment of hydrogen in Japan. The analysis focuses on the four key sectors of storage supplementing the gas grid power generation and transportation detailing the potential range of hydrogen technologies which are expected to penetrate Japanese energy markets up to 2050 and beyond. Alongside key model outcomes the appropriate policy settings governance and market mechanisms are described which underpin the potential hydrogen economy future for Japan. We find that transportation gas grid supplementation and storage end-uses may emerge in significant quantities due to policies which encourage ambitious implementation targets investment in technologies and research and development and the emergence of a future carbon pricing regime. On the other hand for Japan which will initially be dependent on imported hydrogen the cost of imports appears critical to the emergence of broad hydrogen usage particularly in the power generation sector. Further the consideration of demographics in Japan recognizing the aging shrinking population and peoples’ energy use preferences will likely be instrumental in realizing a smooth transition toward a hydrogen economy.
Hydrogen Production Technologies Overview
Jan 2019
Publication
Hydrogen energy became the most significant energy as the current demand gradually starts to increase. Hydrogen energy is an important key solution to tackle the global temperature rise. The key important factor of hydrogen production is the hydrogen economy. Hydrogen production technologies are commercially available while some of these technologies are still under development. This paper reviews the hydrogen production technologies from both fossil and non-fossil fuels such as (steam reforming partial oxidation auto thermal pyrolysis and plasma technology). Additionally water electrolysis technology was reviewed. Water electrolysis can be combined with the renewable energy to get eco-friendly technology. Currently the maximum hydrogen fuel productions were registered from the steam reforming gasification and partial oxidation technologies using fossil fuels. These technologies have different challenges such as the total energy consumption and carbon emissions to the environment are still too high. A novel non-fossil fuel method [ammonia NH3] for hydrogen production using plasma technology was reviewed. Ammonia decomposition using plasma technology without and with a catalyst to produce pure hydrogen was considered as compared case studies. It was showed that the efficiency of ammonia decomposition using the catalyst was higher than ammonia decomposition without the catalyst. The maximum hydrogen energy efficiency obtained from the developed ammonia decomposition system was 28.3% with a hydrogen purity of 99.99%. The development of ammonia decomposition processes is continues for hydrogen production and it will likely become commercial and be used as a pure hydrogen energy source.
Liquid Hydrogen: A Review on Liquefaction, Storage, Transportation, and Safety
Sep 2021
Publication
Decarbonization plays an important role in future energy systems for reducing greenhouse gas emissions and establishing a zero-carbon society. Hydrogen is believed to be a promising secondary energy source (energy carrier) that can be converted stored and utilized efficiently leading to a broad range of possibilities for future applications. Moreover hydrogen and electricity are mutually converted creating high energy security and broad economic opportunities toward high energy resilience. Hydrogen can be stored in various forms including compressed gas liquid hydrogen hydrides adsorbed hydrogen and reformed fuels. Among these liquid hydrogen has advantages including high gravimetric and volumetric hydrogen densities and hydrogen purity. However liquid hydrogen is garnering increasing attention owing to the demand for long storage periods long transportation distances and economic performance. This paper reviews the characteristics of liquid hydrogen liquefaction technology storage and transportation methods and safety standards to handle liquid hydrogen. The main challenges in utilizing liquid hydrogen are its extremely low temperature and ortho- to para-hydrogen conversion. These two characteristics have led to the urgent development of hydrogen liquefaction storage and transportation. In addition safety standards for handling liquid hydrogen must be updated regularly especially to facilitate massive and large-scale hydrogen liquefaction storage and transportation.
Hydrogen Production Cost Forecasts since the 1970s and Implications for Technological Development
Jun 2022
Publication
This study reviews the extant literature on hydrogen production cost forecasts to identify and analyze the historical trend of such forecasts in order to explore the feasibility of wider adoption. Hydrogen is an important energy source that can be used to achieve a carbon-neutral society but the widespread adoption of hydrogen production technologies is hampered by the high costs. The production costs vary depending on the technology employed: gray renewable electrolysis or biomass. The study identifies 174 production cost forecast data points from articles published between 1979 and 2020 and makes a comparative assessment using non-parametric statistical tests. The results show three different cost forecast trends across technologies. First the production cost of gray hydrogen showed an increasing trend until 2015 but started declining after 2015. Second the renewable electrolysis hydrogen cost was the highest of all but has shown a gradual declining trend since 2015. Finally the biomass hydrogen cost has been relatively cheaper up until 2015 after which it became the highest. Renewable electrolysis and biomass hydrogen will be potential candidates (as principal drivers) to reduce CO2 emissions in the future but renewable electrolysis hydrogen is more promising in this regard due to its declining production cost trend. Gray hydrogen can also be an alternative candidate to renewable electrolysis hydrogen because it can be equipped with carbon capture storage (CCS) to produce blue hydrogen although we need to consider additional production costs incurred by the introduction of CCS. The study discusses the technological development and policy implications of the results on hydrogen production costs.
Effects of Hydrogen and Carbon Dioxide on the Laminar Burning Velocities of Methane-air Mixtures
Sep 2021
Publication
The effects of different mole fractions of hydrogen and carbon dioxide on the combustion characteristics of a premixed methane–air mixture are experimentally and numerically investigated. The laminar burning velocity of hydrogen-methane-carbon dioxide-air mixture was measured using the spherically expanding flame method at the initial temperature and pressure of 283 K and 0.1 MPa respectively. Additionally numerical analysis is conducted under steady 1D laminar flow conditions to investigate the adiabatic flame temperature and dominant elementary reactions. The measured velocities correspond with those estimated numerically. The results show that increasing the carbon dioxide mole fraction decreases the laminar burning velocity attributed to the carbon dioxide dilution which decreases the thermal diffusivity and flame temperature. Conversely the velocity increases with the thermal diffusivity as the hydrogen mole fraction increases. Moreover the hydrogen addition leads to chain-branching reactions that produce active H O and OH radicals via the oxidation of hydrocarbons which is the rate-determining reaction.
Graphene Oxide @ Nickel Phosphate Nanocomposites for Photocatalytic Hydrogen Production
Mar 2021
Publication
The graphene oxide @nickel phosphate (GO:NPO) nanocomposites (NCs) are prepared by using a one-pot in-situ solar energy assisted method by varying GO:NPO ratio i.e. 0.00 0.25 0.50 0.75 1.00 1.25 1.50 and 2.00 without adding any surfactant or a structure-directing reagent. As produced GO:NPO nanosheets exhibited an improved photocatalytic activity due to the spatial seperation of charge carriers through interface where photoinduced electrons transferred from NiPO4 to the GO sheets without charge-recombination. Out of the series the system 1.00 GO:NPO NC show the optimum hydrogen production activity (15.37 μmol H2 h−1) towards water splitting under the visible light irradiation. The electronic environment of the nanocomposite GO-NiO6/NiO4-PO4 elucidated in the light of advance experimental analyses and theoretical DFT spin density calculations. Structural advanmcement of composites are well correlated with their hydrogen production activity.
No more items...