Institution of Gas Engineers & Managers

Across Europe permitted blend levels of hydrogen blending into the gas grid are appreciably higher than that currently permitted in the UK up to 12% mol/mol compared with 0.1% mol/mol. Whilst there is some routine blending undertaking – typically power to gas applications three major projects have been undertaken to demonstrate operation of a gas distribution network at higher blend levels of hydrogen.<br/>A Dutch project was completed in 2011 which demonstrated successful operation into a network with new appliances at 20% mol/mol. A German project was completed in 2015 which demonstrated successful operation into an existing gas network with existing appliances at their permitted level of 10% mol/mol. In France an extensive programme is underway to inject hydrogen into a network at 20% mol/mol due to commence injection in 2018.<br/>Each of these projects undertook extensive pre-trial activities and operational data was collected during the Dutch and German trials. The programme of pre-trial work for the French project was particularly extensive and mirrored the work done by HyDeploy. This led to a permit being granted for the French project at 20% mol/mol with injection into the network imminent.<br/>The HyDeploy team has engaged with each of the project teams who have been very co-operative; this has enabled scientific sharing of best practice. In all cases the projects were successful. The participants in the Dutch project were particularly keen to have been able to undertake a similar trial to HyDeploy; a larger trial into existing appliances. However political changes in Holland have precluded that at this time such progress was not limited by technical findings from the work.<br/>A high level overview of the projects and the data provided is summarised in this report. More detailed information is referenced and covered in more detail where required in the appropriate individual topic reports supporting the Exemption.<br/>Click on supplements tab to view the other documents from this report

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.

Energy management is a critical issue for the advancement of fuel cell vehicles because it significantly influences their hydrogen economy and lifetime. This paper offers a comprehensive investigation of the energy management of heavy-duty fuel cell vehicles for road freight transportation. An important and unique contribution of this study is the development of an extensive and realistic representation of the vehicle operation which includes 1750 hours of real-world driving data and variable truck loading conditions. This framework is used to analyze the potential benefits and drawbacks of heuristic optimal and predictive energy management strategies to maximize the hydrogen economy and system lifetime of fuel cell vehicles for road freight transportation. In particular the statistical evaluation of the effectiveness and robustness of the simulation results proves that it is necessary to consider numerous and realistic driving scenarios to validate energy management strategies and obtain a robust design. This paper shows that the hydrogen economy can be maximized as an individual target using the available driving information achieving a negligible deviation from the theoretical limit. Furthermore this study establishes that heuristic and optimal strategies can significantly reduce fuel cell transients to improve the system lifetime while retaining high hydrogen economies. Finally this investigation reveals the potential benefits of predictive energy management strategies for the multi-objective optimization of the hydrogen economy and system lifetime.

The generation of hydrogen from water using light is currently one of the most promising alternative energy sources for humankind but faces significant barriers for large-scale applications due to the low efficiency of existing photo-catalysts. In this work we propose a new route to fabricate nano-hybrid materials able to deliver enhanced photo-catalytic hydrogen evolution combining within the same nanostructure a plasmonic antenna nanoparticle and semiconductor quantum dots (QDs). For each stage of our fabrication process we probed the chemical composition of the materials with nanometric spatial resolution allowing us to demonstrate that the final product is composed of a silver nanoparticle (AgNP) plasmonic core surrounded by satellite Pt decorated CdS QDs (CdS@Pt) separated by a spacer layer of SiO2 with well-controlled thickness. This new type of photoactive nanomaterial is capable of generating hydrogen when irradiated with visible light displaying efficiencies 300% higher than the constituting photo-active components. This work may open new avenues for the development of cleaner and more efficient energy sources based on photo-activated hydrogen generation.

Dark fermentation is a promising method to produce hydrogen from lignocellulosic biomass. This study assessed the influence of temperature phosphate buffer concentration and substrate concentration on direct hydrogen production form cellulose using response surface methodology. Mixed bacterial culture was successfully enriched on cellulose and used as an inoculum for hydrogen production. The model indicated that the highest cumulative hydrogen production (CHP) of 2.14 L H₂/Lmedium could be obtained at 13.5 gcellulose/L 79.5 mM buffer and 32.6 °C. However hydrogen yield is then only 0.58 mol H₂/molhexose due to low substrate conversion efficiency (SCE). Simultaneous optimization of CHP and SCE with desirability function approach resulted in the H₂ yield of 2.71 ± 0.1 mol H2/molhexose and 93.8 ± 1.8% SCE at 3.35 gcellulose/L 69 mM buffer and 32.9 °C. Phosphate concentration above 80 mM decreased H₂ production but had positive effect on cellulose consumption. The bacterial community analysis showed that Ruminiclostridium papyrosolvens was responsible for cellulose hydrolysis. Lachnoclostridium sp. was positively correlated with ethanol production at high phosphate buffer concentration while Caproiciproducens sp. with caproate production at low buffer concentration. The obtained results opens the possibility of simultaneous hydrogen and caproate production from cellulosic substrates.

We examine the employment implications of a domestic net-zero transition and establishment of clean energy export systems for an historically significant energy exporting country through a case study of Australia. The labour impacts of a multi-decadal transition are simulated across both the domestic and export energy systems considering a wide range of energy technologies resources and activities with assessment according to occupation lifecycle stage education and skill requirements. Across all net-zero scenario pathways by mid-century the total gross employment created for the domestic and export sectors comprises 210–490 thousand jobs and 350–510 thousand jobs respectively. This represents a significant expansion of energy sector employment from the current total of 120 thousand across domestic and export sectors an increase from less than 1 % of the total Australian workforce in 2020 to 3–4 % by 2060. The need to build out energy system infrastructure at large-scale over a number of decades results in construction jobs continuing over that timeframe and a subsequent need for a large ongoing operations and maintenance workforce for new energy system assets. Those employed in domestic energy markets work primarily in utility solar PV onshore wind batteries and electricity transmission and distribution activities while export market jobs are dominated by clean hydrogen production and shipping supply chains. Crucially these export jobs are unevenly distributed across the country in regions of highest quality solar resource. All states and territories experience net job growth across each decade to 2060. However in a few sub-state regions net job losses occur in the short-term.

Although most of researchers agree on the elementary reactions behind the sonolytic formation of molecular hydrogen (H₂) from water namely the radical attack of H₂O and H₂O₂ and the free radicals recombination several recent papers ignore the intervention of the dissolved gas molecules in the kinetic pathways of free radicals and hence may wrongly assess the effect of dissolved gases on the sonochemical production of hydrogen. One may fairly ask to which extent is it acceptable to ignore the role of the dissolved gas and its eventual decomposition inside the acoustic cavitation bubble? The present opinion paper discusses numerically the ways in which the nature of dissolved gas i.e. N₂ O₂ Ar and air may influence the kinetics of sonochemical hydrogen formation. The model evaluates the extent of direct physical effects i.e. dynamics of bubble oscillation and collapse events if any against indirect chemical effects i.e. the chemical reactions of free radicals formation and consequently hydrogen emergence it demonstrates the improvement in the sonochemical hydrogen production under argon and sheds light on several misinterpretations reported in earlier works due to wrong assumptions mainly related to initial conditions. The paper also highlights the role of dissolved gases in the nature of created cavitation and hence the eventual bubble population phenomena that may prevent the achievement of the sonochemical activity. This is particularly demonstrated experimentally using a 20 kHz Sinaptec transducer and a Photron SA 5 high speed camera in the case of CO₂-saturated water where degassing bubbles are formed instead of transient cavitation.

The susceptibility of high strength ferritic steels to hydrogen-assisted fracture in hydrogen gas is usually evaluated by mechanical testing in high-pressure hydrogen gas or testing in air after pre-charging the specimens with hydrogen. We have used this second methodology conventionally known as internal hydrogen. Samples were pre-charged in an autoclave under 195 bar of pure hydrogen at 450ºC for 21 hours.<br/>Different chromium-molybdenum steels submitted to diverse quenching and tempering heat treatments were employed. Diverse specimens were also used: small cylindrical samples to measure hydrogen contents and the kinetics of hydrogen egression at room temperature tensile specimens notched tensile specimens with a sharp notch and also compact fracture toughness specimens. Fractographic examination in SEM was finally performed in order to know the way hydrogen modify fracture micromechanisms.<br/>The presence of hydrogen barely affects the conventional tensile properties of the steels but it clearly alters their notched tensile strength and fracture toughness. This is due to the strong effect that stress triaxiality (dependent also on the steel yield strength) has on the accumulation of hydrogen on the notch/crack front region being the displacement rate used in the test another important variable to be controlled due to its influence on hydrogen diffusion to the embrittled process zone. Moreover the modification of fracture micromechanisms was finally determined being ductile (initiation growth and coalescence of microvoids) in the absence of hydrogen and brittle and intergranular under the material conditions of maximum embrittlement.

The effect of hydrogen on short crack propagation under cyclic loading in SA508 Grade 3 Class I low alloy steel is investigated. This low alloy steel is used in manufacturing of pressure vessel installed in Indian nuclear power plants. During operation these pressure vessels are subjected to continuous supply of pressurized hot water at 600 K and hence are susceptible to hydrogen embrittlement. In past research has been conducted on the effect of hydrogen embrittlement on long fatigue crack propagation in this material but the mechanistic understanding and correlation of hydrogen embrittlement with microstructural features in the material can be understood well by studying the effect of hydrogen embrittlement on short fatigue crack propagation. Short fatigue cracks are of the order of 10 µm to 1 mm and unlike long cracks these short cracks strongly interact with the microstructural features in the material such as grain/phase boundaries. The effect of hydrogen embrittlement on short crack propagation is studied by artificial hydrogen charging of the material through electrochemical process. The single edge notch tension (SENT) specimens with an initial notch of the order of 85 to 90 µm are used to study the short crack propagation. The short cracks in hydrogen charged samples initiated from the notch at lower number of loading cycles as compared to the uncharged notched samples for the same value of applied stress range (Δσ). After initiation the short fatigue crack in hydrogen charged samples propagated at higher rate as compared to uncharged samples. This dissimilarity in crack propagation behavior is due to the difference in the interaction of short fatigue crack with the microstructural features for a hydrogen charged and uncharged samples.

In the field of energy storage recently investigated nanocomposites show promise in terms of high hydrogen uptake and release with enhancement in the reaction kinetics. Among several carbonaceous nanovariants like carbon nanotubes (CNTs) fullerenes and graphitic nanofibers reveal reversible hydrogen sorption characteristics at 77 K due to their van der Waals interaction. The spillover mechanism combining Pd nanoparticles on the host metal-organic framework (MOF) show room temperature uptake of hydrogen. Metal or complex hydrides either in the nanocomposite form and its subset nanocatalyst dispersed alloy phases illustrate the concept of nanoengineering and nanoconfinement of particles with tailor-made properties for reversible hydrogen storage. Another class of materials comprising polymeric nanostructures such as conducting polyaniline and their functionalized nanocomposites are versatile hydrogen storage materials because of their unique size high specific surface-area pore-volume and bulk properties. The salient features of nanocomposite materials for reversible hydrogen storage are reviewed and discussed.