Institution of Gas Engineers & Managers

The ultrafine-grained (UFG) duplex microstructure of medium-Mn steel consists of a considerable amount of austenite and ferrite/martensite achieving an extraordinary balance of mechanical properties and alloying cost. In the present work two heat treatment routes were performed on a cold-rolled medium-Mn steel Fe-12Mn-3Al-0.05C (wt.%) to achieve comparable mechanical properties with different microstructural morphologies. One heat treatment was merely austenite-reverted-transformation (ART) annealing and the other one was a successive combination of austenitization (AUS) and ART annealing. The distinct responses to hydrogen ingression were characterized and discussed. The UFG martensite colonies produced by the AUS + ART process were found to be detrimental to ductility regardless of the amount of hydrogen which is likely attributed to the reduced lattice bonding strength according to the H-enhanced decohesion (HEDE) mechanism. With an increase in the hydrogen amount the mixed microstructure (granular + lamellar) in the ART specimen revealed a clear embrittlement transition with the possible contribution of HEDE and H-enhanced localized plasticity (HELP) mechanisms.

The synthesis of a Substitute Natural Gas (SNG) that is compatible with the gas grid composition requirements by using surplus electricity from renewable energy sources looks a favourable solution to store large quantities of electricity and to decarbonise the gas grid network while maintaining the same infrastructure. The most promising layouts for SNG production and the conditions under which SNG synthesis reduces the environmental impacts if compared to its fossil alternative is still largely untapped. In this work six different layouts for the production of SNG and electricity from biomass and fluctuating electricity are compared from the environmental point of view by means of Life Cycle Assessment (LCA) methodology. Global Warming Potential (GWP) Cumulative Energy Demand (CED) and Acidification Potential (AP) are selected as impact indicators for this analysis. The influence of key LCA methodological aspects on the conclusions is also explored. In particular two different functional units are chosen: 1 kg of SNG produced and 1 MJ of output energy (SNG and electricity). Furthermore different approaches dealing with co-production of electricity are also applied. The results show that the layout based on hydrogasification has the lowest impacts on all the considered cases apart from the GWP and the CED with SNG mass as the functional unit and the avoided burden approach. Finally the selection of the multifunctionality approach is found to have a significant influence on technology ranking.

A study was performed to investigate the hydrogen embrittlement behavior of 18-Ni 300 maraging steel produced by selective laser melting and subjected to different heat treatment strategies. Hydrogen was pre-charged into the tensile samples by an electro-chemical method at the constant current density of 1 A m−2 and 50 A m−2 for 48 h at room temperature. Charged and uncharged specimens were subjected to tensile tests and the hydrogen concentration was eventually analysed using quadrupole mass spectroscopy. After tensile tests uncharged maraging samples showed fracture surfaces with dimples. Conversely in H-charged alloys quasi-cleavage mode fractures occurred. A lower concentration of trapped hydrogen atoms and higher elongation at fracture were measured in the H-charged samples that were subjected to solution treatment prior to hydrogen charging compared to the as-built counterparts. Isothermal aging treatment performed at 460 °C for 8 h before hydrogen charging increased the concentration of trapped hydrogen giving rise to higher hydrogen embrittlement susceptibility.

Increased use of renewable energy combined with intensified electrification could prove decisive for the world to meet key climate goals by 2050. This study from the International Renewable Energy Agency (IRENA) highlights immediately deployable cost-effective options for countries to fulfil climate commitments and limit the rise of global temperatures. The envisaged energy transformation would also reduce net costs and bring significant socio-economic benefits such as increased economic growth job creation and overall welfare gains.<br/>The report – the second under the Global Energy Transformation banner – expands IRENA’s comprehensive roadmap which examines technology pathways and policy implications to ensure a sustainable energy future. Ramping up electricity to over half of the global energy mix (up from one-fifth currently) in combination with renewables would reduce the use of fossil fuels responsible for most greenhouse-gas emissions.

During 2020 the Scottish Government in partnership with Highlands and Islands Enterprise and Scottish Enterprise commissioned Arup and E4Tech to carry out a hydrogen assessment to deepen our evidence base in order to inform our policies on hydrogen going forward. The assessment aims to investigate how and where hydrogen may fit within the evolving energy system technically geographically and economically. To assist in this consideration a key part of the Hydrogen Assessment is the development of distinct viable scenarios for hydrogen deployment in Scotland and the economic assessment of those scenarios.<br/>From our assessment it is clear that hydrogen is not just an energy and emissions reduction opportunity; it could also have an important role in generating new economic opportunities in Scotland. The assessment forms an important part of the evidence base that informed the development of the Hydrogen Policy Statement.

Hydrogen is an economical source of clean energy that has been utilized by industry for decades. In recent years demand for hydrogen has risen significantly. Hydrogen sources include water electrolysis hydrocarbon steam reforming and fossil fuels which emit hazardous greenhouse gases and therefore have a negative impact on global warming. The increasing worldwide population has created much pressure on natural fuels with a growing gap between demand for renewable energy and its insufficient supply. As a result the environment has suffered from alarming increases in pollution levels. Biohydrogen is a sustainable energy form and a preferable substitute for fossil fuel. Anaerobic fermentation photo fermentation microbial and enzymatic photolysis or combinations of such techniques are new approaches for producing biohydrogen. For cost-effective biohydrogen production the substrate should be cheap and renewable. Substrates including algal biomass agriculture residue and wastewaters are readily available. Moreover substrates rich in starch and cellulose such as plant stalks or agricultural waste or food industry waste such as cheese whey are reported to support dark- and photo-fermentation. However their direct utilization as a substrate is not recommended due to their complex nature. Therefore they must be pretreated before use to release fermentable sugars. Various pretreatment technologies have been established and are still being developed. This article focuses on pretreatment techniques for biohydrogen production and discusses their efficiency and suitability including hybrid-treatment technology

The present research focuses on the investigation of an in situ hydrogen charging effect during Crack Tip Opening Displacement testing (CTOD) on the fracture toughness properties of X65 pipeline steel. This grade of steel belongs to the broader category of High Strength Low Alloy Steels (HSLA) and its microstructure consists of equiaxed ferritic and bainitic grains with a low volume fraction of degenerated pearlite islands. The studied X65 steel specimens were extracted from pipes with 19.15 mm wall thickness. The fracture toughness parameters were determined after imposing the fatigue pre-cracked specimens on air on a specific electrolytic cell under a slow strain rate bending loading (according to ASTM G147-98 BS7448 and ISO12135 standards). Concerning the results of this study in the first phase the hydrogen cations’ penetration depth the diffusion coefficient of molecular and atomic hydrogen and the surficial density of blisters were determined. Next the characteristic parameters related to fracture toughness (such as J KQ CTODel CTODpl) were calculated by the aid of the Force-Crack Mouth Open Displacement curves and the relevant analytical equations.

The World Energy Transitions Outlook preview outlines a pathway for the world to achieve the Paris Agreement goals and halt the pace of climate change by transforming the global energy landscape. This preview presents options to limit global temperature rise to 1.5°C and bring CO₂ emissions closer to net zero by mid-century offering high-level insights on technology choices investment needs and the socio-economic contexts of achieving a sustainable resilient and inclusive energy future.



Meeting CO₂ reduction targets by 2050 will require a combination of: technology and innovation to advance the energy transition and improve carbon management; supportive and proactive policies; associated job creation and socio-economic improvements; and international co-operation to guarantee energy availability and access.



Among key findings:

• Proven technologies for a net-zero energy system already largely exist today. Renewable power green hydrogen and modern bioenergy will dominate the world of energy of the future.
• A combination of technologies is needed to keep us on a 1.5°C climate pathway. These include increasingly efficient energy production to ensure economic growth; decarbonised power systems that are dominated by renewables; increased use of electricity in buildings industry and transport to support decarbonisation; expanded production and use of green hydrogen synthetic fuels and feedstocks; and targeted use of sustainably sourced biomass.
• In anticipation of the coming energy transition financial markets and investors are already directing capital away from fossil fuels and towards other energy technologies including renewables.
• Energy transition investment will have to increase by 30% over planned investment to a total of USD 131 trillion between now and 2050 corresponding to USD 4.4 trillion on average every year.
• National social and economic policies will play fundamental roles in delivering the energy transition at the speed required to restrict global warming to 1.5°C.

This preview identifies opportunities to support informed policy and decision making to establish a new global energy system. Following this preview and aligned with the UN High-Level Dialogue process the International Renewable Energy Agency (IRENA) will release the full report which will provide a comprehensive vision and accompanying policy measures for the transition.

The conversion of H2 and CO2 to liquid fuels via Power-to-Liquid (PtL) processes is gaining attention. With their higher energy densities compared to gases the use of synthetic liquid fuels is particularly interesting in hard-to-abate sectors for which decarbonisation is difficult. However PtL poses new challenges for the synthesis: away from syngas-based continuously run large-scale plants towards more flexible small-scale concepts with direct CO2-utilisation. This review provides an overview of state of the art synthesis technologies as well as current developments and pilot plants for the most prominent PtL routes for methanol DME and Fischer–Tropsch-fuels. It should serve as a benchmark for future concepts guide researchers in their process development and allow a technological evaluation of alternative reactor designs. In the case of power-to-methanol and power-to-FT-fuels several pilot plants have been realised and the first commercial scale plants are planned or already in operation. In comparison power-to-DME is much less investigated and in an earlier stage of development. For methanol the direct CO2 hydrogenation offers advantages through less by-product formation and lower heat development. However increased water formation and lower equilibrium conversion necessitate new catalysts and reactor designs. While DME synthesis offers benefits with regards to energy efficiency operational experience from laboratory tests and pilot plants is still missing. Furthermore four major process routes for power-to-DME are possible requiring additional research to determine the optimal concept. In the case of Fischer–Tropsch synthesis catalysts for direct CO2 utilisation are still in an early stage. Consequently today’s Fischer–Tropsch-based PtL requires a shift to syngas benefiting from advances in co-electrolysis and reverse water-gas shift reactor design.

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.