Publications

The rare earth metals have been identified by the European Union and the United States as being at greatest supply risk of all the materials for clean energy technologies. Of particular concern are neodymium and dysprosium both of which are employed in neodymium–iron–boron based magnets. Recycling of magnets based on these materials and contained within obsolete electronic equipment could provide an additional and secure supply. In the present work hydrogen has been employed as a processing agent to decrepitate sintered neodymium–iron–boron based magnets contained within hard disk drives into a demagnetised hydrogenated powder. This powder was then extracted mechanically from the devices with an extraction efficiency of 90 ± 5% and processed further using a combination of sieves and ball bearings to produce a powder containing <330 parts per million of nickel contamination. It is then possible for the extracted powder to be re-processed in a number of ways namely directly by blending and re-sintering to form fully dense magnets by Hydrogenation Disproportionation Desorption Recombination processing to produce an anisotropic coercive powder suitable for bonded magnets by re-melting; or by chemical extraction of the rare earth elements from the alloy. For example it was shown that by the re-sintering route it was possible to recover >90% of the magnetic properties of the starting material with significantly less energy than that employed in primary magnet production. The particular route used will depend upon the magnetic properties required the level of contamination of the extracted material and the compositional variation of the feedstock. The various possibilities have been summarised in a flow diagram.

Environmental issues related to global warming are constantly pushing the fossil fuel-based energy sector toward an efficient and economically viable utilization of renewable energy. However challenges related to renewable energy call for alternative routes of its conversion to fuels and chemicals by an emerging Power-to-X approach. Methane is one such high-valued fuel that can be produced through renewables-powered electrolytic routes. Such routes employ alkaline electrolyzers proton exchange membrane electrolyzers and solid oxide electrolyzers commonly known as solid oxide electrolysis cells (SOECs). SOECs have the potential to utilize the waste heat generated from exothermic methanation reactions to reduce the expensive electrical energy input required for electrolysis. A further advantage of an SOEC lies in its capacity to co-electrolyze both steam and carbon dioxide as opposed to only water and this inherent capability of an SOEC can be harnessed for in situ synthesis of methane within a single reactor. However the concept of in situ methanation in SOECs is still at a nascent stage and requires significant advancements in SOEC materials particularly in developing a cathode electrocatalyst that demonstrates activity toward both steam electrolysis and methanation reactions. Equally important is the appropriate reactor design along with optimization of cell operating conditions (temperature pressure and applied potential). This review elucidates those developments along with research and development opportunities in this space. Also presented here is an efficiency comparison of different routes of synthetic methane production using SOECs in various modes that is as a source of hydrogen syngas and hydrogen/carbon dioxide mixture and for in situ methane synthesis.

Tensile and fatigue tests were performed on an AA2198 aluminum alloy in the T851 condition in ambient air and liquid hydrogen (LH2). All fatigue tests were performed under load control at a frequency of 20 Hz and a stress ratio of R=0.1. The Gecks-Och-Function [1] was fitted on the measured cyclic lifetimes.<br/><br/>The tensile strength in LH2 was measured to be 46 % higher compared to the value determined at ambient conditions and the fatigue limit was increased by approximately 60 %. Both S-N curves show a distinct S-shape but also significant differences. Under LH2 environment the transition from LCF- to HCF-region as well as the transition to the fatigue limit is shifted to higher cyclic lifetimes compared to ambient test results. The investigation of the crack surfaces showed distinct differences between ambient and LH2 conditions. These observed differences are important factors in the fatigue behavior change.

Underexpanded jet releases from circular nozzles have been studied extensively both experimentally and numerically. However jet releases from rectangular openings have received much less attention and information on their dispersion behaviour is not as widely available. In this paper Computational Fluid Dynamics (CFD) is used to assess the suitability of using a pseudo-source approach to model jet releases from rectangular openings. A comparative study is performed to evaluate the effect of nozzle shape on jet structure and dispersion characteristics for underexpanded hydrogen jet releases. Jet releases issuing from a circular nozzle and rectangular nozzles with aspect ratios ranging from two to eight are modelled including resolution of the near-field behaviour. The experimental work of Ruggles and Ekoto (2012 2014) is used as a basis for validating the modelling approach used and an additional case study in which jets with a stagnation-to-ambient pressure ratio of 300:1 are modelled is also performed. The CFD results show that for the 10:1 pressure ratio release the hazard volume and hazard distance remain largely unaffected by nozzle shape. For the higher pressure release the hazard volume is larger for the rectangular nozzle releases than the equivalent release through a circular orifice though the distance to lower flammability limit is comparable across the range of nozzle shapes considered. For both of the release pressures simulated the CFD results illustrate that a pseudo-source approach produces conservative results for all nozzle shapes considered. This finding has useful practical implications for consequence analysis in industrial applications such as the assessment of leaks from flanges and connections in pipework.

This study presents an integrated techno-environmental assessment of hydrogen production from natural gas and biomethane combined with CO₂ capture and storage (CCS). We have included steam methane reforming (SMR) and autothermal reforming (ATR) for syngas production. CO₂ is captured from the syngas with a novel vacuum pressure swing adsorption (VPSA) process that combines hydrogen purification and CO₂ separation in one cycle. As comparison we have included cases with conventional amine-based technology. We have extended standard attributional Life Cycle Assessment (LCA) following ISO standards with a detailed carbon balance of the biogas production process (via digestion) and its by-products. The results show that the life-cycle greenhouse gas (GHG) performance of the VPSA and amine-based CO₂ capture technologies is very similar as a result of comparable energy consumption. The configuration with the highest plant-wide CO₂ capture rate (almost 100% of produced CO₂ captured) is autothermal reforming with a two-stage water-gas shift and VPSA CO₂ capture – because the latter has an inherently high CO₂ capture rate of 98% or more for the investigated syngas. Depending on the configuration the addition of CCS to natural gas reforming-based hydrogen production reduces its life-cycle Global Warming Potential by 45–85 percent while the other environmental life-cycle impacts slightly increase. This brings natural gas-based hydrogen on par with renewable electricity-based hydrogen regarding impacts on climate change. When biomethane is used instead of natural gas our study shows potential for net negative greenhouse gas emissions i.e. the net removal of CO₂ over the life cycle of biowaste-based hydrogen production. In the special case where the biogas digestate is used as agricultural fertiliser and where a substantial amount of the carbon in the digestate remains in the soil the biowaste-based hydrogen reaches net-negative life cycle greenhouse gas emissions even without the application of CCS. Addition of CCS to biomethane-based hydrogen production leads to net-negative emissions in all investigated cases.

Hydrogen embrittlement (HE) is a critical issue that affects the reliability of hydrogenation reactors. The hydrogen diffusivity/trap characteristics of 2.25Cr-1Mo-0.25V steel are important parameters mainly used to study the HE mechanism of steel alloys. In this work the hydrogen diffusivity/trap characteristics of heat-treated (annealed) and untreated 2.25Cr-1Mo-0.25V steel were studied using an electrochemical permeation method. The microstructures of both 2.25Cr-1Mo-0.25V steels were investigated by metallurgical microscopy. The effect of cementite on the hydrogen diffusivity/trap mechanisms was studied using thermodynamics-based and Lennard–Jones potential theories. The results revealed that the cementite located at the grain boundaries and at the interfaces of lath ferrite served as a kind of hydrogen trap (i.e. an irreversible hydrogen trap). In addition hydrogen was transported from ferrite to cementite via up-hill diffusion thereby supporting the hypothesis of cementite acting as a hydrogen trap.

The permanent introduction of green hydrogen into the energy economy would require that a discriminating selection be made of its use in the sectors where its value is optimal in terms of relative cost and life cycle reduction in carbon dioxide emissions. Consequently hydrogen can be used as an energy storage medium when intermittent wind and solar power exceed certain penetration in the grid likely above 40% and in road transportation right away to begin displacing gasoline and diesel fuels. To this end the proposed approach is to utilize current technologies represented by PHEV in light-duty and HEV in heavy-duty vehicles where a high-performance internal combustion engine is used with a fuel comprised of 15–20% green hydrogen and 85–89% green methane depending on vehicle type. This fuel designated as RHYME takes advantage of the best attributes of hydrogen and methane results in lower life cycle carbon dioxide emissions than BEVs or FCEVs and offers a cost-effective and pragmatic approach both locally as well as globally in establishing hydrogen as part of the energy economy over the next ten to thirty years.

To understand the effect of surface machining on the resistance of AISI 316L to SCC (stress–corrosion cracking) in marine environments we tested nuts surface-machined by different methods in a seawater-spraying chamber. Two forms of cracks were observed: on the machined surface and underneath it. On the surface cracks connected with the pitting sites were observed to propagate perpendicular to the hoop-stress direction identifying them as stress–corrosion cracks. Under the surface catastrophic transgranular cracks developed likely driven by hydrogen embrittlement caused by the chloride-concentrating level of humidity in the testing environment. Under constant testing conditions significantly different SCC resistance was observed depending on how the nuts had been machined. Statistical evaluation of the nut surface-crack density indicates that machining by a “form” tool yields a crack density one order of magnitude lower than machining by a “single-point” tool. Microstructural analysis of form-tool-machined nuts revealed a homogeneous deformed subsurface zone with nanosized grains leading to enhanced surface hardness. Apparently the reduced grain size and/or the associated mechanical hardening improve resistance to SCC. The nanograin subsurface zone was not observed on nuts machined by a single-point tool. Surface roughness measurements indicate that single-point-tool-machined nuts have a rougher surface than form-tool machined nuts. Apparently surface roughness reduces SCC resistance by increasing the susceptibility to etch attack in Cl--rich solutions. The results of X-ray diffractometry and transmission electron microscopy diffractometry indicate that machining with either tool generates a small volume fraction (< 0.01) of strain-induced martensite. However considering the small volume fraction and absence of martensite in regions of cracking martensite is not primarily responsible for SCC in marine environments.

This report is the public version of the deliverable B.3.7 'Life cycle assessment of Hydrogen and Fuel Cell Technologies - Inventory of work performed by projects funded under FCH JU'; it provides an overview of the progress achieved so far and a comprehensive analysis on Life Cycle Assessment (LCA) for various hydrogen technologies and processes. The review considers 73 Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU) founded projects: for some of those the LCA study was requested in the call topic while other projects decided to perform the LCA study on a voluntary basis. The LCAs have been assessed regarding the adherence to guideline recommendations (e.g. reported properties system boundary definitions goal and scope definitions) methodology and overall quality of the work. Methodology is a critical issue for the comparability of results as this is only possible if all LCAs follow the same guidelines; in addition LCAs were often only partially fulfilling the selected guideline requirements. It is recommended that future FCH 2 JU call topics asking for environmental analysis to be performed are setting out some minimum requirements such as the guidelines to be used and the impacts to be assessed. Based on the outcome of this analysis a harmonisation effort in the approach to LCA for the FCH JU founded projects is proposed; in particular a Life Cycle Inventory (LCI) database useful for the projects is required togheter with the identification of a reference cases to be used as benchmark for future LCAs.

In this study ethylene glycol (EG) and terephthalic acid (TPA) were used to generate hydrogen using copper electrodes in an alkaline aqueous solution and the corresponding reaction mechanism was experimentally investigated. Both EG and TPA produced hydrogen; however TPA consumed OH− inhibiting the production of intermediary compounds of EG and causing EG to actively react with H2O ultimately leading to enhanced hydrogen production. In addition the initiation potential of water decomposition of the EG and TPA alkaline aqueous solution was 1.0 V; when 1.8 V (vs. RHE) was applied the hydrogen production reached 440 mmol L⁻¹ which was substantially greater than the hydrogen production rate of 150 mmol L⁻¹ during water decomposition.

The use of clean hydrogen is likely to form a key part of a net-zero emissions future and has the potential to replace natural gas for end use heating. As part of BDR Thermea Group Baxi Heating UK are at the forefront of hydrogen boiler development. Working with the Hy4Heat programme hydrogen fuelled boilers have been produced for inclusion in trial sites across the UK. This presentation will explore progress to date together with the hydrogen-ready boiler concept.

The National Hydrogen Roadmap provides a blueprint for the development of a hydrogen industry in Australia.

Recently there has been a considerable amount of work undertaken (both globally and domestically) seeking to quantify the economic opportunities associated with hydrogen. The National Hydrogen Roadmap takes that analysis a step further by focusing on how those opportunities can be realised.

National Hydrogen Roadmap

The National Hydrogen Roadmap provides a blueprint for the development of a hydrogen industry in Australia.

The primary objective of the Roadmap is to provide a blueprint for the development of a hydrogen industry in Australia. With a number of activities already underway it is designed to help inform the next series of investment amongst various stakeholder groups (e.g. industry government and research) so that the industry can continue to scale in a coordinated manner.

Pathways to an economically sustainable industry

The low emissions hydrogen value chain now consists of a series of mature technologies. While there is considerable scope for further R&D this level of maturity has meant that the narrative has shifted from one of technology development to market activation.

Barriers to market activation stem from a lack of supporting infrastructure and/or the cost of hydrogen supply. However both barriers can be overcome via a series of strategic investments along the value chain from both the private and public sector.

The report shows that while government assistance is needed to kick-start the industry it can become economically sustainable thereafter. This is demonstrated by first assessing the target price of hydrogen needed for it be competitive with other energy carriers and feedstocks. Second the assessment considers the current state of the industry namely the cost and maturity of the underpinning technologies and infrastructure. It then identifies the material cost drivers and consequently the key priorities and areas for investment needed to make hydrogen competitive in each of the identified markets.

The opportunity for hydrogen to compete favourably on a cost basis in local applications such as transport and remote area power systems is within reach based on potential cost reductions to 2025. Further the development of a hydrogen export industry represents a significant opportunity for Australia and a potential 'game changer' for the local industry and the broader energy sector due to associated increases in scale."

You can read the full report on the CSIRO website at this link

Of all the available resources given to mankind the sunlight is perhaps the most abundant renewable energy resource providing more than enough energy on earth to satisfy all the needs of humanity for several hundred years. Therefore it is transient and sporadic that poses issues with how the energy can be harvested and processed when the sun does not shine. Scientists assume that electro/photoelectrochemical devices used for water splitting into hydrogen and oxygen may have one solution to solve this hindrance. Water electrolysis-generated hydrogen is an optimal energy carrier to store these forms of energy on scalable levels because the energy density is high and no air pollution or toxic gas is released into the environment after combustion. However in order to adopt these devices for readily use they have to be low-cost for manufacturing and operation. It is thus crucial to develop electrocatalysts for water splitting based on low-cost and land-rich elements. In this review I will summarize current advances in the synthesis of low-cost earth-abundant electrocatalysts for overall water splitting with a particular focus on how to be linked with photoelectrocatalytic water splitting devices. The major obstacles that persist in designing these devices. The potential future developments in the production of efficient electrocatalysts for water electrolysis are also described.

Hydrogen interaction with metal atoms is of prime focus for many energy related applications like hydrogen storage hydrogen evolution using catalysis etc. Although hydrogen binding with many main group alkaline and transition metals is quite well understood its binding properties with lanthanides are not well reported. In this article by density functional theory studies we show how a rare earth metal cerium binds with hydrogen when decorated over a heteropolar 2D material hexagonal boron nitride. Each cerium adatom is found to bind eight hydrogen molecules which is a much higher number than has been reported for transition metal atoms. However the highest binding energy occurs at four hydrogen molecules. This anomaly therefore is investigated in the present article using first-principles calculations. The number density of hydrogen molecules adsorbed over the cerium adatom is explained by investigating the electronic charge volume interactions owing to a unique geometrical arrangement of the guest hydrogen molecules. The importance of geometrical encapsulation in enhancing electronic interactions is explained.

Extensive energy consumption has become a major concern due to increase of greenhouse gas emissions and global warming. Hence hydrogen has attracted attention as a green fuel with zero carbon emission for green transportation through production of electric vehicles with hydrogen fuel cells. South Korea has launched a hydrogen society policy with the objective of expanding production of hydrogen from renewable energy sources. The hydrogen economy will play a critical role in reducing atmospheric pollution and global  arming. However new development of infrastructure for hydrogen refuelling and increasing awareness of the hydrogen economy is required together with reduced prices of hydrogen-driven vehicles that are promising options for a sustainable green  hydrogen economy.

It is important to examine in detail how the distribution of academic research topics related to renewable energy is structured and which topics are likely to receive new attention in the future in order for scientists to contribute to the development of renewable energy. This study uses an advanced probabilistic topic modeling to statistically examine the temporal changes of renewable energy topics by using academic abstracts from 2010–2019 and explores the properties of the topics from the perspective of future signs such as weak signals. As a result in strong signals methods for optimally integrating renewable energy into the power grid are paid great attention. In weak signals interest in large-capacity energy storage systems such as hydrogen supercapacitors and compressed air energy storage showed a high rate of increase. In not-strong-but-well-known signals comprehensive topics have been included such as renewable energy potential barriers and policies. The approach of this study is applicable not only to renewable energy but also to other subjects.

The growing of fossil fuel burning leads to increase CO2 and H2 emissions which cause increasing of global warming that has brought big attention. As a result enormous researches have been made to reduce CO2 and H2 build up in the environment. One of the most promising approaches for managing CO2 and H2 gases percentage in the atmosphere is capturing and storage them inside proper materials. Therefore the design of new materials for carbon dioxide and hydrogen storage has received increasing research attention. Four derivatives of coumarine linked to thiazolidinone were synthesized in good yields by reacting 3-(2-Phenylaminoacetyl)coumarine and 2-phenylimino thiazolidinone-4-one in a solution of anhydrous sodium acetate /glacial acetic acid at 120° for 5-6 hours. The synthesised organic compounds were identified by using different techniques such as 1H NMR 13C NMR FTIR and energy dispersive X-ray spectra. The agglomeration shape and porosity of the particles were determined utilizing scanning electron microscopy (SEM) and microscopy images analysis. The capacity of carbon dioxide (CO2) and hydrogen (H2) adsorption on the prepared organic materials at 323 K 50 bar ranged from 22 to 31 cm3 /g and hydrogen from 4 to 12 cm3 /g for the four synthesised compounds which contain phenyl substituted with chloro nitro and bromo groups was found to be the most active adsorbent surfaces for carbon dioxide and hydrogen storage.

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.

Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE) with consequent overpressure fragments projection and eventually a fireball. In this work all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990’s. After the validation the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally future works on the modelling activity of the LH2 BLEVE are suggested.

The high energy consumption and production of undesired oxygen greatly restrict the wide adoption of water electrolysis for hydrogen production. In a paper recently published in Nature Catalysis Wang and coworkers rationally introduce aldehydes for oxidation at anode to replace oxygen evolution reaction which can produce hydrogen and value-added products at low potential realizing efficient bipolar hydrogen production with high-purity. Moreover these aldehydes are biomass-derived and contribute to sustainable hydrogen production

We have designed a new method for electrochemical hydrogen charging which allows us to charge very thin coarse-grained specimens from the bottom and perform nanomechanical testing on the top. As the average grain diameter is larger than the thickness of the sample this setup allows us to efficiently evaluate the mechanical properties of multiple single crystals with similar electrochemical conditions. Another important advantage is that the top surface is not affected by corrosion by the electrolyte. The nanoindentation results show that hydrogen reduces the activation energy for homogenous dislocation nucleation by approximately 15–20% in a (001) grain. The elastic modulus also was observed to be reduced by the same amount. The hardness increased by approximately 4% as determined by load-displacement curves and residual imprint analysis.

New vehicle technologies and fuels will drive the future of road transport in Australia. Increased availability of battery electric vehicles hydrogen fuel cell vehicles biofuels and associated recharging and refuelling infrastructure will:

• give consumers more choice
• provide productivity emissions reduction fuel security and air quality benefits

Our Future Fuels Strategy: Discussion Paper sets out the direction and practical actions to enable the private sector to commercially deploy low emissions road transport technologies at scale."

A multi-scale modeling approach for simulating the tensile behavior of the corroded aluminum alloy 2024 T3 was developed accounting for both the geometrical features of corrosion damage and the effect of corrosion-induced hydrogen embrittlement (HE). The approach combines two Finite Element (FE) models: a model of a three-dimensional Representative Unit Cell (RUC) representing an exfoliated area and its correspondent hydrogen embrittled zone (HEZ) and a model of the tensile specimen. The models lie at the micro- and macro-scales respectively. The characteristics of the HEZ are determined from measurements of nanoindentation hardness conducted on pre-corroded specimens. Using the model of the RUC the local homogenized mechanical behavior of the corroded material is simulated. Then the behavior of the exfoliated areas is assigned into different areas (elements) of the tensile specimen and final analyses are performed to simulate the tensile behavior of the corroded material. The approach was applied to model specimens after 8 16 and 24 h exposure periods of the Exfoliation Corrosion (EXCO) test. For validation of the approach tensile tests were used. The numerical results show that this approach is suitable for accurately simulating the tensile behavior of pre-corroded experimental specimens accounting for both geometrical features of corrosion damage and corrosion-induced HE.

The main objective of the article is to provide a thorough review of currently used AC-DC converters for alkaline and proton exchange membrane (PEM) electrolyzers in power grid or wind energy conversion systems. Based on the current literature this article aims at emphasizing the advantages and drawbacks of AC-DC converters mainly based on thyristor rectifier bridges and chopper-rectifiers. The analysis is mainly focused on the current issues for these converters in terms of specific energy consumption current ripple reliability efficiency and power quality. From this analysis it is shown that thyristors-based rectifiers are particularly fit for high-power applications but require the use of active and passive filters to enhance the power quality. By comparison the association combination of the chopper-rectifier can avoid the use of bulky active and passive filters since it can improve power quality. However the use of a basic chopper (i.e. buck converter) presents several disadvantages from the reliability energy efficiency voltage ratio and current ripple point of view. For this reason new emerging DC-DC converters must be employed to meet these important issues according to the availability of new power switching devices. Finally based on the authors’ experience in power conversion for PEM electrolyzers a discussion is provided regarding the future challenges that must face power electronics for green hydrogen production based on renewable energy sources.

The experimental evidence for the contraction of volume of gold implanted with hydrogen at low doses is presented. The contraction of lattice upon the addition of other elements is very rare and extraordinary in the solid-state not only for gold but also for many other solids. To explain the underlying physics the pure kinetic theory of absorption is not adequate and the detailed interaction of hydrogen in the lattice needs to be clarified. Our analysis points to the importance of the formation of hydride bonds in a dynamic manner and explains why these bonds become weak at higher doses leading to the inverse process of volume expansion frequently seen in metallic hydrogen containers.