United Kingdom

Underground Hydrogen Storage (UHS) has gathered interest over the past decade as an efficient means of storing energy. Although a significant number of research and demonstration projects have sought to understand the associated technical challenges it is yet to be achieved on commercial scales. We highlight case studies from town gas and blended hydrogen storage focusing on leakage pathways and hydrogen reactivity. Experience from helium storage serves as an analogue for the containment security of hydrogen as the two gases share physiochemical similarities including small molecular size and high diffusivity. Natural gas storage case studies are also investigated to highlight well integrity and safety challenges. Technical parameters identified as having adverse effects on storage containment security efficiency and hydrogen reactivity were then used to develop high-level and site-specific screening criteria. Thirty-two depleted offshore hydrocarbon reservoirs in the UK Continental Shelf (UKCS) are identified as potential storage formations based on the application of our high-level criteria. The screened fields reflect large hydrogen energy capacities low cushion gas requirements and proximity to offshore wind farms thereby highlighting the widespread geographic availability and potential for efficient UHS in the UKCS. Following the initial screening we propose that analysis of existing helium concentrations and investigation of local tectonic settings are key site-specific criteria for identifying containment security of depleted fields for stored hydrogen.

The high efficiency light weight and reliability of hydrogen energy electrochemical equipment are among the future development directions. Membrane electrode assemblies (MEAs) and electrolyzers as key components have structures and strengths that determine the efficiency of their power generation and the hydrogen production efficiency of electrolyzers. This article summarizes the evolution of membrane electrode and electrolyzer structures and their power and efficiency in recent years highlighting the significant role of integrated structures in promoting proton transport and enhancing performance. Finally it proposes the development direction of integrating electrolyte and electrode manufacturing using phase-change methods.

Thermo-chemical conversion of waste plastics offers a sustainable strategy for integrated waste management and clean energy generation. To address the challenges of low gas yield and rapid catalyst deactivation due to coking in conventional gasification processes an innovative three-stage chemical looping gasification (CLG) system specifically designed for enhanced hydrogen-rich syngas production was proposed in this work. A comparative analysis between conventional gasification and the staged CLG system were firstly conducted coupled with online gas analysis for mechanistic elucidation. The influence of Fe/Al molar ratios in oxygen carriers and their cyclic stability were systematically examined through multicycle experiments. Results showed that the three-stage CLG in the presence of Fe1Al2 demonstrated exceptional performance achieving 95.23 mmol/gplastic of H2 and 129.89 mmol/gplastic of syngas respectively representing 1.32-fold enhancement over conventional method. And the increased H2/CO ratio (2.68-2.75) reflected better syngas quality via water-gas shift. Remarkably the oxygen carrier maintained nearly 100% of its initial activity after 7 redox cycles attributed to the incorporation of Al2O3 effectively mitigating sintering and phase segregation through metal-support interactions. These findings establish a three-stage CLG configuration with Fe-Al oxygen carriers as an efficient platform for efficient hydrogen production from waste plastics contributing to sustainable waste valorisation and carbon-neutral energy systems.

Minimizing carbon dioxide emissions is crucial due to the generation of energy from fossil fuels. The significance of carbon capture and storage (CCS) technology which is highly successful in mitigating carbon emissions has increased. On the other hand hydrogen is an important energy carrier for storing and transporting energy and technologies that rely on hydrogen have become increasingly promising as the world moves toward a more environmentally friendly approach. Nevertheless the integration of CCS technologies into power production processes is a significant challenge requiring the enhancement of the combined power generation–CCS process. In recent years there has been a growing interest in process intensification (PI) which aims to create smaller cleaner and more energy efficient processes. The goal of this research is to demonstrate the process intensification potential and to model and simulate a hybrid integrated–intensified adsorptive-membrane reactor process for simultaneous carbon capture and hydrogen production. A comprehensive multi-scale multi-phase dynamic computational fluid dynamics (CFD)-based process model is constructed which quantifies the various underlying complex physicochemical phenomena occurring at the pellet and reactor levels. Model simulations are then performed to investigate the impact of dimensionless variables on overall system performance and gain a better understanding of this cyclic reaction/separation process. The results indicate that the hybrid system shows a steady-state cyclic behavior to ensure flexible operating time. A sustainability evaluation was conducted to illustrate the sustainability improvement in the proposed process compared to the traditional design. The results indicate that the integrated–intensified adsorptive-membrane reactor technology enhances sustainability by 35% to 138% for the chosen 21 indicators. The average enhancement in sustainability is almost 57% signifying that the sustainability evaluation reveals significant benefits of the integrated–intensified adsorptive-membrane reactor process compared to HTSR + LTSR.

As the global demand for energy increases and the transition to renewable and clean sources accelerates microgrid (MG) has emerged as a promising solution. Hydrogen fuel cell vehicles (HFCVs) offer significant advantages over gasoline vehicles in terms of reducing carbon dioxide emissions. However the development of HFCVs is hindered by the substantial up-front costs of hydrogen refueling stations (HRSs) coupled with the high cost of hydrogen transportation and the limitations of the hydrogen supply chain. This research proposes a multimicrogrid (MMG) system that integrates hydrogen energy and utilizes it as the HRS for fuel vehicle refueling. An adaptive hydrogen energy management method is employed for fuel cell vehicles to optimize the coupling between the transportation network and the power system. An integrated transportation state assessment model is developed and a smart MMG system is deployed to receive information from the transportation network. Building on this foundation an adaptive hydrogen scheduling model is developed. HFCVs are influenced by the hydrogen price adjustments leading them to travel to different MGs for refueling which in turn regulates the unit output of the MMG system. The MMG system is then integrated with the IEEE 33 bus distribution system to analyze the daily load balance. This integrated approach results in reduced traffic congestion lower MG costs and optimized power distribution network load balance.

Large-scale H2 storage in depleted hydrocarbon reservoirs offers a practical way to use existing energy infra structure to address renewable energy intermittency. Cushion gases often constitute a large initial investment especially when expensive H2 is used. Cheaper alternatives such as CO2 or in-situ CH4 can reduce costs and in the case of CO2 integrate within carbon capture and storage systems. This study explored cushion and working gas dynamics through numerically modelling a range of storage scenarios in laterally extensive reservoirs – such as those in the Southern North Sea. In all simulations the cushion and working gases were separated laterally to limit contact surface area and therefore mixing. This work provides valuable insights into (i) capacity estima tions of CO2 storage and H2 withdrawal (ii) macro-scale fluid dynamics and (iii) the effects of gas mixing trends on H2 purity. The results underscore key trade-offs between CO2 storage volumes and H2 withdrawal and purity

To meet the new regulation for the deployment of alternative fuels infrastructure which sets targets for electric recharging and hydrogen refuelling infrastructure by 2025 or 2030 a large infrastructure comprising trucksuitable hydrogen refuelling stations will soon be required. However further standardisation is required to support the uptake of hydrogen for heavy-duty transport for Europe’s green energy future. Hydrogen-powered vehicles require pure hydrogen as some contaminants can reduce the performance of the fuel cell even at very low levels. Even if previous projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment sampling systems and methods have yet to be developed for heavy-duty hydrogen refuelling stations (HD-HRS). This study reviews different aspects of the sampling of hydrogen at heavy-duty hydrogen refuelling stations for purity assessment with a focus on the current and future specifications and operations at HD-HRS. This study describes the state-of-the art of sampling systems currently under development for use at HD-HRS and highlights a number of aspects which must be taken into consideration to ensure safe and accurate sampling: risk assessment for the whole sampling exercise selection of cylinders methods to prepare cylinders before the sampling filling pressure and venting of the sampling systems.

In the present study pilot simulations of the phenomena of blast wave and fireball generated by the rupture of a high-pressure (35 MPa) hydrogen tank (volume 72 L) due to fire were carried out. The computational fluid dynamics (CFD) model includes the realizable k-ε model for turbulence and the eddy dissipation model coupled with the one-step chemical reaction mechanism for combustion. The simulation results were compared with experimental data on a stand-alone hydrogen tank rupture in a bonfire test. The simulations provided insights into the interaction between the blast wave propagation and combustion process. The simulated blast wave decay is approximately identical to the experimental data concerning pressure at various distances. Fireball is first ignited at the ground level which is considered to be due to stagnation flow conditions. Subsequently the flame propagates toward the interface between hydrogen and air.

Hydrogen energy is crucial for achieving net zero targets making the resilience of hydrogen supply chains (HSCs) increasingly important. Understanding current research on HSC resilience is key to enhancing it. Few studies summarise HSC resilience evaluation methods and link them to the general supply chain resilience and complex adaptive system (CAS) evaluation approaches. This study addresses this gap by systematically reviewing the literature on HSC resilience evaluations defining HSC resilience and conducting content analysis. It proposes a conceptual framework integrating technical operational and organisational perspectives. Each perspective is further subdivided based on the course of events resulting in a system-based HSC resilience evaluation frame work with three layers of analysis. By linking HSC indicators with CAS theory and supply chain performance metrics the study offers novel insights into HSC resilience evaluations identifies research gaps provides prac tical guidance for practitioners and outlines future research directions for advancing HSC resilience understanding.

Hydrogen (H2) offers a green medium for storing the excess from renewables production instead of dumping it thus being crucial to decarbonisation efforts. Hydrogen also offers a storage medium for the grid’s cheap electricity to be used during grid peak demand or grid power cutoffs. Funded by the Scottish Government’s Emerging Energy Technologies this paper presents the design and performance analysis of a hydrogen uninterruptible power supply (H2GEN) for Cygnas Solutions Ltd. which is intended to enable continuity of supply in the residential sector while eradicating the need for environmentally and health risky lead–acid batteries and diesel generator backup. This paper presents the design optimal sizing and analysis of two H2Gen architectures one powered by the grid alone and the other powered by both the grid and a renewable (PV) source. By developing a model of each architecture in the HOMER space and using residential location weather data the home yearly load–demand profile and the grid yearly power outages profile in the developed models the optimal sizing of each H2Gen design was realised by minimising the costs while ensuring the H2Gen meets the home power demand during grid outages To enable HOMER to optimise its selection the sizes technical specifications and costs of all the market-available H2GEN components were added in the HOMER search space. Moreover the developed models were also used in assessing the sensitivity of the simulation outputs to several changes in the modelled system design and settings. Using a residential home with frequent power outages in New Delhi India as a case study it was found that the optimal sizing of H2Gen Architecture 1 is comprised of a 2 kW electrolyser a 0.2 kg type-I tank and a 2 kW water-cooled fuel cell directly connected to the AC bus offering an operational lifetime of 14.3 years. It was also found that the optimal sizing of Architecture 2 is comprised of a 1 kV PV utilised with the same 2 kW electrolyser 0.2 kg type-I tank and 2 kW water-cooled fuel cell connected to the AC bus. While the second design was found to have a higher capital cost due to the added PV it offered a more cost-effective and environmentally friendly architecture which contributes to the ongoing energy transition. This paper further investigated the capacity expansion of each H2GEN architecture to meet higher load demands or increased grid power outages. From the analysis of the simulation results it has been concluded that the most feasible and cost-effective H2GEN system expansion for meeting increased power demands or increased grid outages can be realised by using the developed models for optimally sizing the expanded H2Gen on a case-by-case basis because the increase in these profiles is highly time-dependent (for example an increased load demand or increased grid outage in the morning can be met by the PV while in the evening it must be met by the H2GEN). Finally this paper investigated the impact of other environmental variables such as the temperature and relative humidity on the H2GEN’s performance and provided further insights into increasing the overall system efficiency and cost benefit through utilising the H2GEN’s exhaust heat in the home space for heating/cooling and selling the electrolyser exhaust’s O2 as a commodity.

This paper aims at the development and validation of a computational fluid dynamic (CFD) model for simulations of the refuelling process through the entire equipment of the hydrogen refuelling station (HRS). The absence of such models hinders the design of inherently safer refuelling protocols for an arbitrary combination of HRS equipment hydrogen storage parameters and environmental conditions. The CFD model is validated against the complete process of refuelling lasting 195s in Test No.1 performed by the National Renewable Energy Laboratory (NREL). The test equipment includes high-pressure tanks of HRS pressure control valve (PCV) valves pipes breakaway hose and nozzle all the way up to three onboard tanks. The model accurately reproduced hydrogen temperature and pressure through the entire line of HRS equipment. A standout feature of the CFD model distinguishing it from simplified models is the capability to predict temperature non-uniformity in onboard tanks a crucial factor with significant safety implications.

The scientific and industrial communities worldwide have recently achieved impressive technical advances in developing innovative electrocatalysts and electrolysers for water and seawater splitting. The viability of water electrolysis for commercial applications however remains elusive and the key barriers are durability cost performance materials manufacturing and system simplicity especially with regard to running on practical water sources like seawater. This paper therefore primarily aims to provide a concise overview of the most recent disruptive water-splitting technologies and materials that could reshape the future of green hydrogen production. Starting from water electrolysis fundamentals the recent advances in developing durable and efficient electrocatalysts for modern types of electrolysers such as decoupled electrolysers seawater electrolysers and unconventional hybrid electrolysers have been represented and precisely annotated in this report. Outlining the most recent advances in water and seawater splitting the paper can help as a quick guide in identifying the gap in knowledge for modern water electrolysers while pointing out recent solutions for cost-effective and efficient hydrogen production to meet zero-carbon targets in the short to near term.

As the global energy transition progresses a range of drivers and barriers will continue to shape consumer attitudes and behavioural intentions towards emerging low-carbon technologies. The innovation-decision process for technologies composing the residential sector such as hydrogen-fuelled heating and cooking appliances is inherently governed by the complex interplay between perceptual cognitive and emotional factors. In response this study responds to the call for an integrated research perspective to advance theoretical and empirical insights on consumer engagement in the domestic hydrogen transition. Drawing on online survey data collected in the United Kingdom where a policy decision on ‘hydrogen homes’ is set for 2026 this study systematically explores whether an integrated modelling approach supports higher levels of explanatory and predictive power. Leveraging the foundations of the unified theory of domestic hydrogen acceptance the analysis suggests that production perceptions public trust perceived relative advantage safety perceptions knowledge and awareness and positive emotions will shape consumer support for hydrogen homes. Conversely perceived disruptive impacts perceived socio-economic costs financial perceptions and negative emotions may impede the domestic hydrogen transition. Consumer acceptance stands to significantly shape deployment prospects for hydrogen boilers and hobs which are perceived to be somewhat advantageous to natural gas appliances from a technological and safety perspective. The study attests to the predictive benefits of adopting an integrated theoretical perspective when modelling the early stages of the innovation-decision process while acknowledging opportunities for leveraging innovative research approaches in the future. As national hydrogen economies gain traction adopting a neuroscience-based approach may help deepen scientific understanding regarding the neural psychological and emotional signatures shaping consumer perspectives towards hydrogen homes.

Gaseous hydrogen storage is the most mature technology for fuel cell vehicles. The main safety concern is the catastrophic consequences of tank rupture in a fire i.e. blast waves fireballs and projectiles. This paper sum marises research on the development and validation of the breakthrough microleaks-no-burst (μLNB) safety technology of explosion-free in any fire self-venting Type IV tanks that do not require a thermally-activate pressure relief device (TPRD). The invention implies the melting of the hydrogen-tight liner of the Type IV tank before the hydrogen-leaky double-composite wall loses load-bearing ability. Hydrogen then flows through the natural microchannels in the composites and burns in microflames or together with resin. The unattainable to competitive products feature of the technology is the ability to withstand any fire from smouldering to extreme impinging hydrogen jet fires. Innovative 70 MPa tanks made of carbon-carbon carbon-glass and carbon-basalt composites were tested in characteristic for gasoline/diesel spill fires with a specific heat release rate of HRR/A = 1 MW/m2 . Standard unprotected Type III and IV tanks will explode in such intensity fire. The technology excludes hydrogen accumulation in naturally ventilated enclosures. It reduces the risk of hydrogen vehicles to an acceptable level below that of fossil fuel cars including underground parking tunnels etc. The performance of self-venting tanks is studied for fire intervention scenarios: removal from fire and fire extinction by water. It is concluded that novel tanks allow standard fire intervention strategies and tactics. Self-venting operation of the 70 MPa tank is demonstrated in extreme jet fire conditions under impinging hydrogen jet fire (70 MPa) with huge HRR/A = 19.5 MW/m2 . This technology excludes tank rupture in fires onboard trains ships and planes where hazard distances cannot be implemented i.e. provides an unprecedented level of life safety and property protection.

This study investigates hydrogen-diesel dual-fuelling specifically for a modern 4.4L 4-cylinder heavy-duty diesel engine using extensive one-dimensional combustion modelling in Ricardo WAVE. Parametric analyses from 900 to 2200 rpm speeds and 0 to 17.5% hydrogen fractions introduced via port injection are undertaken to assess the effect of exhaust gas recirculation (EGR) for controlling NOx. Moreover impacts on key indicators like brake power torque thermal efficiency and emissions are also evaluated. Results revealed that the benefits of hydrogen enrichment are highly dependent on operating conditions. At speeds above 1700 rpm and hydrogen mass fraction of 17.5% remarkable gains were attained increasing brake power and torque by up to 17% and 16.5% respectively. Brake-specific diesel consumption (BSDC) improves by 29% at higher speeds due to hy drogen’s larger energy content. NOx emissions display a trade-off decreasing substantially by 96% at lower speeds but increasing by 43% at 2200 rpm with 17.5% hydrogen.

Industry emits around a quarter of global greenhouse gas (GHG) emissions. This paper presents the first comprehensive review to identify the main decarbonization options for this sector and their abatement potentials. First we identify the important GHG emitting processes and establish a global average baseline for their current emissions intensity and energy use. We then quantify the energy and emissions reduction potential of the most significant abatement options as well as their technology readiness level (TRL). We find that energy-intensive industries have a range of decarbonization technologies available with medium to high TRLs and mature options also exist for decarbonizing low-temperature heat across a wide range of industrial sectors. However electrification and novel process change options to reduce emissions from high-temperature and sector-specific processes have much lower TRLs in comparison. We conclude by highlighting important barriers to the deployment of industrial decarbonization options and identifying future research development and demonstration needs.

Co-optimizing energy and water resources in a microgrid can increase efficiency and improve economic performance. Energy-water storage (EWS) devices are crucial components of a high-efficient energy-water microgrid (EWMG). The state of charge (SoC) at the end of the first day of operation is one of the most significant variables in EWS devices since it is used as a parameter to indicate the starting SoC for the second day which influences the operating cost for the second day. Hence this paper examines the benefits and applicability of a lookahead optimization strategy for an EWMG integrated with multi-type energy conversion technologies and multienergy demand response to supply various energy-water demands related to electric/hydrogen vehicles and commercial/residential buildings with the lowest cost for two consecutive days. In addition a hybrid info-gap/robust optimization technique is applied to cover uncertainties in photovoltaic power and electricity prices as a tri-level optimization framework without generating scenarios and using the probability distribution functions. Duality theory is also used to convert the problem into a single-level MILP so that it can be solved by CPLEX. According to the findings the implemented energy-water storage systems and look-ahead strategy accounted for respectively 4.03% and 0.43% reduction in the total cost.

This study emphasises the growing relevance of hydrogen as a green energy source in meeting the growing need for sustainable energy solutions. It foregrounds the importance of assessing the environmental consequences of hydrogen-generating processes for their long-term viability. The article compares several hydrogen production processes in terms of scalability costeffectiveness and technical improvements. It also investigates the environmental effects of each approach considering crucial elements such as greenhouse gas emissions water use land needs and waste creation. Different industrial techniques have distinct environmental consequences. While steam methane reforming is cost-effective and has a high production capacity it is coupled with large carbon emissions. Electrolysis a technology that uses renewable resources is appealing but requires a lot of energy. Thermochemical and biomass gasification processes show promise for long-term hydrogen generation but further technological advancement is required. The research investigates techniques for improving the environmental friendliness of hydrogen generation through the use of renewable energy sources. Its ultimate purpose is to offer readers a thorough awareness of the environmental effects of various hydrogen generation strategies allowing them to make educated judgements about ecologically friendly ways. It can ease the transition to a cleaner hydrogen-powered economy by considering both technological feasibility and environmental issues enabling a more ecologically conscious and climate-friendly energy landscape.

Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes enabling efficient hydrogen energy utilisation and green hydrogen production. In addition to the essential cell stacks the system of PEMFC or PEMWE consists of four sub-systems for managing gas supply power thermal and water respectively. Due to the system’s complexity even a small fluctuation in a certain sub-system can result in an unexpected response leading to a reduced performance and stability. To improve the system’s robustness and responsiveness considerable efforts have been dedicated to developing advanced control strategies. This paper comprehensively reviews various control strategies proposed in literature revealing that traditional control methods are widely employed in PEMFC and PEMWE due to their simplicity yet they suffer from limitations in accuracy. Conversely advanced control methods offer high accuracy but are hindered by poor dynamic performance. This paper highlights the recent advancements in control strategies incorporating machine learning algorithms. Additionally the paper provides a perspective on the future development of control strategies suggesting that hybrid control methods should be used for future research to leverage the strength of both sides. Notably it emphasises the role of artificial intelligence (AI) in advancing control strategies demonstrating its significant potential in facilitating the transition from automation to autonomy.

Experiments are performed in hydrogen-oxygen mixtures at the cryogenic temperature of 77 K with the equivalence ratio of 1.5 and 2.0. The optical fibers pressure sensors and the smoked foils are used to record the flame velocity overpressure evolution curve and detonation cells respectively. The 1st and 2nd shock waves are captured and they finally merge to form a stronger precursor shock wave prior to the onset of detonation. The cryogenic temperature will cause the larger expansion ratio which results in the occurrence of strong flame acceleration. The stuttering mode the galloping mode and the deflagration mode are observed when the initial pressure decreases from 0.50 atm to 0.20 atm with the equivalence ratio of 1.5 and the detonation limit is within 0.25-0.30 atm. The heat loss effect on the detonation limit is analysed. In addition the regularity of detonation cell is investigated and the larger post-shock specific heat ratio !"" and the lower normalized activation energy # at lower initial pressure will cause the more regular detonation cell. Also the detonation cell width is predicted by a model of = ($) ⋅ Δ# and the prediction results are mainly consistent with the experimental results.

Hydrogen vehicles encompassing fuel cell electric vehicles (FCEVs) are pivotal within the UK’s energy landscape as it pursues the goal of net-zero emissions by 2050. By markedly diminishing dependence on fossil fuels FCEVs including hydrogen vehicles wield substantial influence in shaping the circular economy (CE). Their impact extends to optimizing resource utilization enabling zero-emission mobility facilitating the integration of renewable energy sources supplying adaptable energy storage solutions and interconnecting diverse sectors. The widespread adoption of hydrogen vehicles accelerates the UK’s transformative journey towards a sustainable CE. However to fully harness the benefits of this transition a robust investigation and implementation of safety measures concerning hydrogen vehicle (HV) use are indispensable. Therefore this study takes a holistic approach integrating quantitative risk assessment (QRA) and an adaptive decision-making trial and evaluation laboratory (DEMATEL) framework as pragmatic instruments. These methodologies ensure both the secure deployment and operational excellence of HVs. The findings underscore that the root causes of HV failures encompass extreme environments material defects fuel cell damage delivery system impairment and storage system deterioration. Furthermore critical driving factors for effective safety intervention revolve around cultivating a safety culture robust education/training and sound maintenance scheduling. Addressing these factors is pivotal for creating an environment conducive to mitigating safety and risk concerns. Given the intricacies of conducting comprehensive hydrogen QRAs due to the absence of specific reliability data this study dedicates attention to rectifying this gap. A sensitivity analysis encompassing a range of values is meticulously conducted to affirm the strength and reliability of our approach. This robust analysis yields precise dependable outcomes. Consequently decision-makers are equipped to discern pivotal underlying factors precipitating potential HV failures. With this discernment they can tailor safety interventions that lay the groundwork for sustainable resilient and secure HV operations. Our study navigates the intersection of HVs safety and sustainability amplifying their importance within the CE paradigm. Using the careful amalgamation of QRA and DEMATEL methodologies we chart a course towards empowering decision-makers with the insights to steer the hydrogen vehicle domain to safer horizons while ushering in an era of transformative eco-conscious mobility.

Plastics have become integral to modern life playing crucial roles in diverse industries such as agriculture electronics automotive packaging and construction. However their excessive use and inadequate management have had adverse environmental impacts posing threats to terrestrial and marine ecosystems. Consequently researchers are increasingly searching for more sustainable ways of managing plastic wastes. Pyrolysis a chemical recycling method holds promise for producing valuable fuel sustainably. This study explores the process of the pyrolysis of plastic and incorporates recent advancements. Additionally the study investigates the integration of reforming into the pyrolysis process to improve hydrogen production. Hydrogen a clean and eco-friendly fuel holds significance in transport engines power generation fuel cells and as a major commodity chemical. Key process parameters influencing the final products for pyrolysis and in-line reforming are evaluated. In light of fossil fuel depletion and climate change the pyrolysis and in-line reforming strategy for hydrogen production is anticipated to gain prominence in the future. Amongst the various strategies studied the pyrolysis and in-line steam reforming process is identified as the most effective method for optimising hydrogen production from plastic wastes.

In this study we evaluate the technical viability of storing hydrogen in a deep UKCS aquifer formation through a series of numerical simulations utilising the compositional simulator CMG-GEM. Effects of various operational parameters such as injection and production rates number and length of storage cycles and shut-in periods on the performance of the underground hydrogen storage (UHS) process are investigated in this study. Results indicate that higher H2 operational rates degrade both the aquifer's working capacity and H2 recovery during the withdrawal phase. This can be attributed to the dominant viscous forces at higher rates which lead to H2 viscous fingering and gas gravity override of the native aquifer water resulting in an unstable displacement of water by the H2 gas. Furthermore analysis of simulation results shows that longer and less frequent storage cycles lead to higher storage capacity and decreased H2 retrieval. We conclude that UHS in the studied aquifer is technically feasible however a thorough evaluation of the operational parameters is necessary to optimise both storage capacity and H2 recovery efficiency.

Low-cost green hydrogen production will be key in reaching net zero carbon emissions by 2050. Green hydrogen can be produced by electrolysis using renewable energy including wind energy. However the configuration of offshore wind-to-hydrogen systems is not yet standardised. For example electrolysis can take place onshore or offshore. This work presents a framework to assess and quantify which configuration is more resilient so that security of hydrogen supply is incorporated in strategic decisions with the following key findings. First resilience should be assessed according to hydrogen supply rather than hydrogen production. This allows the framework to be applicable for all identified system configurations. Second resilience can be quantified according to the quantity ratio and lost revenue of the unsupplied hydrogen.

Increasingly stringent emission standards have led shippers and port operators to consider alternative energy sources which can reduce emissions while minimizing capital investment. It is essential to understand whether there is a certain economic investment gap for alternative energy. The present work mainly focuses on the simulation study of ships using ammonia and hydrogen fuels arriving at Guangzhou Port to investigate the emission advantages and cost-benefit analysis of ammonia and hydrogen as alternative fuels. By collecting actual data and fuel consumption emissions of ships arriving at Guangzhou Port the present study calculated the pollutant emissions and cost of ammonia and hydrogen fuels substitution. As expected it is shown that with the increase of NH3 in fuel mixed fuels will effectively reduce CO and CO2 emissions. Compared to conventional fuel the injection of NH3 increases the NOx emission. However the cost savings of ammonia fuel for CO2 SOx and PM10 reduction are higher than that for NOx. In terms of pollutants ammonia is less expensive than conventional fuels when applied to the Guangzhou Port. However the cost of fuel supply is still higher than conventional energy as ammonia has not yet formed a complete fuel supply and storage system for ships. On the other hand hydrogen is quite expensive to store and transport resulting in higher overall costs than ammonia and conventional fuels even if no pollutants are produced. At present conventional fuels still have advantage in terms of cost. With the promotion of ammonia fuel technology and application the cost of supply will be reduced. It is predicted that by 2035 ammonia will not only have emission reduction benefits but also will have a lower overall economic cost than conventional fuels. Hydrogen energy will need longer development and technological breakthroughs due to the limitation of storage conditions.