Publications

A field test series where a composite pressure vessel for hydrogen is exploded by fire 1) to provide the facts and the data for the safety distance based on overpressure; 2) to validate the current status of mitigation barrier per KGS FP216 and further designs for developments of the codes and standards relating to hydrogen refueling stations. A pair of barriers to be tested are installed approximately 4 m apart standing face to face. The explosion source is a type-4 composite vessel of 175 L filled with compressed hydrogen up to 70 MPa. The vessel is in the middle of the barriers and the body part is heated with an LPG burner until it blows out. The incident overpressures from the blast are measured with 40 high-speed pressure sensors which are respectively installed 2 to 32 m away from the explosion. In the tests with the barrier constructed per the current status of KGS FP216 the explosion of the vessel resulted in partial destruction of the reinforced concrete barrier and made the steel plate barrier dissociated from the foundation then flew away approximately 25 m. The peak overpressure was 14.65 kPa at 32 m. The test data will be further analyzed to select the barriers for the subsequent tests and to develop the codes and standards for hydrogen refueling stations.

Scaling up clean hydrogen supply in the near future is critical to achieving China’s hydrogen development target. This study established an electrolytic hydrogen development mechanism considering the generation mix and operation optimization of power systems with access to hydrogen. Based on the incremental cost principle we quantified the provincial and national clean hydrogen production cost performance levels in 2030. The results indicated that this mechanism could effectively reduce the production cost of clean hydrogen in most provinces with a national average value of less than 2 USD·kg−1 at the 40-megaton hydrogen supply scale. Provincial cooperation via power transmission lines could further reduce the production cost to 1.72 USD·kg−1. However performance is affected by the potential distribution of hydrogen demand. From the supply side competitiveness of the mechanism is limited to clean hydrogen production while from the demand side it could help electrolytic hydrogen fulfil a more significant role. This study could provide a solution for the ambitious development of renewables and the hydrogen economy in China.

Green hydrogen has recently gained importance as a key element in the transition to a low-carbon energy future sparking a boom in possible production regions. This article aims at situating incipient hydrogen production in the Argentine province of Río Negro within a global production network (GPN). The early configuration of the hydrogen-GPN includes several stakeholders and is contested in many ways. To explore the possible materialization of the hydrogen economy in Argentina this article links GPN literature to the concept of sociotechnical imaginaries. In so doing this study finds three energy imaginaries linked to hydrogen development: First advocates of green hydrogen (GH2) project a sociotechnical imaginary in which GH2 is expected to promote scientific and technological progress. Second proponents of blue hydrogen point to Vaca Muerta and the role of natural gas for energy autonomy. Third opponents of the GH2 project question the underlying growth and export model emphasizing conservation and domestic energy sovereignty. The competition between different capital fractions i.e. green and fossil currently poses the risk of pro-fossil path decisions and lock-in effects. Current power constellations have led to the replacement of green with low-emission resulting in the promotion of multi-colored hydrogen. This is particularly evident in the draft for the new national hydrogen law and the actors involved in defining the national hydrogen strategy. The conceptual combination of actors and their interests their current power relations and the sociotechnical imaginaries they deploy illustrates how Argentina's energy future is already being shaped today.

Hydrogen is seen as a key energy carrier to reduce CO2 emissions. Two main production options for hydrogen with low CO2 intensity are water electrolysis and natural gas reforming with Carbon Capture and Storage known as green and blue hydrogen. Northern Norway has a surplus of renewable energy and natural gas availability from the Barents Sea which can be used to produce hydrogen. However exports are challenging due to the large distances to markets and lack of energy infrastructure. This study explores the profitability of hydrogen exports from this Arctic region. It considers necessary investments in hydrogen technology and capacity expansions of wind farms and the power grid. Various scenarios are investigated with different assumptions for investment decisions. The critical question is how exogenous factors shape future regional hydrogen production and export. The results show that production for global export may be profitable above 90 €/MWh excluding costs for storage and transport with blue hydrogen being cheaper than green. Depending on the assumptions a combination of liquid hydrogen and ammonia export might be optimal for seaborne transport. Exports to Sweden can be profitable at prices above 60 €/MWh transported by pipelines. Expanding power generation capacity can be crucial and electricity and hydrogen exports are unlikely to co-exist.

Côte d’Ivoire has substantially neglected crop residues from farms in rural areas so this study aimed to provide strategies for the sustainable conversion of these products to hydrogen. The use of existing data showed that in the Côte d’Ivoire there were up to 16801306 tons of crop residues from 11 crop types in 2019 from which 1296424.84 tons of hydrogen could potentially be derived via theoretical gasification and dark fermentation approaches. As 907497.39 tons of hydrogen is expected annually the following estimations were derived. The three hydrogen-project implementation scenarios developed indicate that Ivorian industries could be supplied with 9026635 gigajoules of heat alongside 17910 cars and 4732 buses in the transport sector. It was estimated that 817293.95 tons of green ammonia could be supplied to farmers. According to the study 5727992 households could be expected to have access to 1718.40 gigawatts of electricity. Due to these changes in the transport energy industry and agricultural sectors a reduction of 1644722.08 tons of carbon dioxide per year could theoretically be achieved. With these scenarios around 263276.87 tons of hydrogen could be exported to other countries. The conversion of crop residues to hydrogen is a promising opportunity with environmental and socio-economic impacts. Therefore this study requires further extensive research.

This study introduces a novel hybrid solar–biomass cogeneration power plant that efficiently produces heat electricity carbon dioxide and hydrogen using concentrated solar power and syngas from cotton stalk biomass. Detailed exergy-based thermodynamic economic and environmental analyses demonstrate that the optimized system achieves an exergy efficiency of 48.67% and an exergoeconomic factor of 80.65% and produces 51.5 MW of electricity 23.3 MW of heat and 8334.4 kg/h of hydrogen from 87156.4 kg/h of biomass. The study explores four scenarios for green hydrogen production pathways including chemical looping reforming and supercritical water gasification highlighting significant improvements in levelized costs and the environmental impact compared with other solar-based hybrid systems. Systems 2 and 3 exhibit superior performance with levelized costs of electricity (LCOE) of 49.2 USD/MWh and 55.4 USD/MWh and levelized costs of hydrogen (LCOH) of between 10.7 and 19.5 USD/MWh. The exergoenvironmental impact factor ranges from 66.2% to 73.9% with an environmental impact rate of 5.4–7.1 Pts/MWh. Despite high irreversibility challenges the integration of solar energy significantly enhances the system’s exergoeconomic and exergoenvironmental performance making it a promising alternative as fossil fuel reserves decline. To improve competitiveness addressing process efficiency and cost reduction in solar concentrators and receivers is crucial.

Hydrogen has the potential to be an important source of clean energy but the development of efficient and cost-effective methods for storing hydrogen is a key challenge that needs to be addressed in order to make widespread use of hydrogen as a possible energy sourc. There are different methods for storing hydrogen (i.e. compressed it at high pressures liquefied by cooling the hydrogen to a temperature of -253°C and stored with a chemical compound) each with its own advantages and disadvantages.<br/>MAST3RBoost (Maturing the Production Standards of Ultraporous Structures for High Density Hydrogen Storage Bank Operating on Swinging Temperatures and Low Compression) is a European project which aims to provide a solid benchmark of cold-adsorbed H2 storage (CAH2) at low compression (100 bar or below) by maturation of a new generation of ultraporous materials for mobility applications i.e. H2-powered vehicles including road and railway air-borne and waterborne transportation. Based on a new generation of Machine Learning-improved ultraporous materials – such as Activated Carbons (ACs) and high-density MOFs (Metal-organic Frameworks) – MAST3RBoost project will enable a disruptive path to meet the industry goals by developing the first worldwide adsorption-based demonstrator at the kg-scale.<br/>The design of the tank is supported by numerical investigation by mean of the use of Computational Fluid Dynamic (CFD) commercial code. In this a paper a preliminary analysis of the refilling of tank is presented focused on the effect of different tank configurations on the hydrogen temperature and on the hydrogen adsorption.

Fuel cells (FCs) and hydrogen technologies are emerging renewable energy sources with promising results when applied to wastewater treatment (WWT). These devices serve not only for power generation but some specific FCs can be employed for degradation of pollutants and synthesis of intermediates needed in WWT. Microbial FCs are potent devices for WWT even containing refractory pollutants. Despite being a nascent technology with high capital expenses the use of cost-effective materials reduction of operational cost and increased generation of energy and value-added chemicals such as hydrogen will facilitate the market penetration through selected niches and hybridization with alternative WWT technologies.

Technological change is often seen as part of the solution to problems of global sustainability. A wide-ranging literature on how path dependent—often fossil fuel-based—socio-technical configurations can be overcome by more sustainable configurations has emerged over the last two decades. One potential transition pathway to transform electricity heat and mobility systems as well as industrial production is the use of hydrogen. In recent years hydrogen has received increasing attention as part of decarbonisation strategies in many countries as well as by international organisations such as the International Energy Agency or the International Renewable Energy Agency. Also in Germany it has become a central component of climate change policy and is seen by some actors almost as a kind of panacea where the use of hydrogen is expected to decarbonise a wide range of sectors. Policy makers have the ambition for Germany to become a leader in hydrogen development and therefore help to contribute to what Grubler called ‘grand patterns of technological change’. The aim of this paper is to analyse whether relevant actors share expectations for transition pathways based on hydrogen which would foster wide diffusion. Our empirical analysis shows that there are multiple contested pathways both in terms of how hydrogen is produced as well as in which applications or sectors it is to be used. This causes uncertainty and slows down hydrogen developments in Germany. We contribute to an emerging literature on the politics of contested transition pathways and also critically engage with Grubler’s ‘grand patterns’ argument. Results support the idea that the concept of socio-technical pathways allows to expose tensions between competing values and interests. The German government is under considerable pressure regarding competing visions on hydrogen transition pathways. A targeted political prioritisation of hydrogen applications could mitigate tensions and support a shared vision.

This paper proposes a systematic optimization framework to jointly determine the optimal location and sizing decisions of renewables and hydrogen storage in a power network to achieve the transition to low-carbon networks efficiently. We obtain these strategic decisions based on the multi-period alternating current optimal power flow (AC MOPF) problem that jointly analyzes power network renewable and hydrogen storage interactions at the operational level by considering the uncertainty of renewable output seasonality of electricity demand and electricity prices. We develop a tailored solution approach based on second-order cone programming within a Benders decomposition framework to provide globally optimal solutions. In a test case we show that the joint integration of renewable sources and hydrogen storage and consideration of the AC MOPF model significantly reduces the operational cost of the power network. In turn our findings can provide quantitative insights to decision-makers on how to integrate renewable sources and hydrogen storage under different settings of the hydrogen selling price renewable curtailment cost emission tax price and conversion efficiency.

To reduce carbon dioxide emissions from the steel industry efforts are made to introduce a steelmaking route based on hydrogen reduction of iron ore instead of the commonly used cokebased reduction in a blast furnace. Changing fundamental pieces of steelworks affects the functions of most every system unit involved and thus warrants the question of how such a transition could optimally take place over time and no rigorous attempts have until now been made to tackle this problem mathematically. This article presents a steel plant optimization model written as a mixed-integer non-linear programming problem where aging blast furnaces and basic oxygen furnaces could potentially be replaced with shaft furnaces and electric arc furnaces minimizing costs or emissions over a long-term time horizon to identify possible transition pathways. Example cases show how various parameters affect optimal investment pathways stressing the necessity of appropriate planning tools for analyzing diverse cases.

A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems namely PV/T- and CPV/T-coupling PEMEC respectively are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00 with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.

Global warming’s major cause is the emission of greenhouse-effect gases (GHG) especially carbon dioxide (CO2) whose main source is the combustion of fossil fuels. Fossil fuels serve as the primary energy source in many industries including shipping which is the focus of this study. One of the measures proposed to tackle GHG emissions is the development of green shipping corridors - carbon-free shipping routes that require the transition to alternative fuels which are gaining competitiveness. One of the reasons for that is carbon pricing which taxes CO2 emissions. However the lack of consensus on the most cost-advantageous alternative fuel in the long run results in the delay of the implementation of green shipping corridors. To make it more accessible for stakeholders to conduct an economic analysis of the various options a framework to determine and minimize the costs of transitioning from fossil fuels to any alternative fuel is proposed over the period of one voyage considering the lost opportunity cost the deployment cost of bunkering vessels at the necessary call ports the cost of converting the vessel the car-bon emissions tax cost and the fuel cost. This will allow stakeholders to choose the most economical alternative fuel accelerating the development of green shipping corridor initiatives. To validate the effectiveness of the framework it was applied in a case study involving a shipowner seeking to transition from heavy fuel oil (HFO) to Ammonia Hydrogen Liquefied Natural Gas (LNG) or Methanol. This study faced limitations due to the unknown costs of installing bunkering vessels for Ammonia and Hydrogen. However it evaluates the cost-effectiveness of alternative fuels providing insights into their short-term economic viability. The results showed that Hydrogen is the most costadvantageous fuel until a deployment cost per bunkering vessel of 1990285$ for a sailing speed of 22 knots and 2190171$ for a sailing speed of 18 knots is reached after which LNG becomes the most economical option regardless of variations in the carbon tax. Moreover a sensitivity analysis was conducted to determine the effects of variations in parameters such as carbon tax fuel prices and vessel conversion costs in the total cost of each fuel option. Results highlighted that even though HFO remains the most economical fuel option even when considering a high increase in carbon tax the cost gap between HFO and alternative fuels narrows significantly with the increase in carbon tax. Furthermore the sailing speed impacts the fuels’ competitiveness as the cost difference between HFO and alternative fuels decreases at higher speeds.

Nanomaterials have attracted great interest in recent years because of the unusual mechanical electrical electronic opticalmagnetic and surface properties. The high surface/volume ratio of these materials has significant implications with respectto energy storage. Both the high surface area and the opportunity for nanomaterial consolidation are key attributes of thisnew class of materials for hydrogen storage devices. Nanostructured systems including carbon nanotubes nano-magnesiumbased hydrides complex hydride/carbon nanocomposites boron nitride nanotubes TiS2/MoS2 nanotubes alanates polymernanocomposites and metal organic frameworks are considered to be potential candidates for storing large quantities of hydrogen.Recent investigations have shown that nanoscale materials may offer advantages if certain physical and chemical effects related tothe nanoscale can be used efficiently. The present review focuses the application of nanostructured materials for storing atomicor molecular hydrogen. The synergistic effects of nanocrystalinity and nanocatalyst doping on the metal or complex hydrides forimproving the thermodynamics and hydrogen reaction kinetics are discussed. In addition various carbonaceous nanomaterialsand novel sorbent systems (e.g. carbon nanotubes fullerenes nanofibers polyaniline nanospheres and metal organic frameworksetc.) and their hydrogen storage characteristics are outlined.

Hydrogen has a key role to play in decarbonising industry and other sectors of society. It is important to develop low-carbon hydrogen production technologies that are cost-effective and energy-efficient. Sorption-enhanced steam methane reforming (SE-SMR) is a developing low-carbon (blue) hydrogen production process which enables combined hydrogen production and carbon capture. Despite a number of key benefits the process is yet to be fully realised in terms of efficiency. In this work a sorption-enhanced steam methane reforming process has been intensified via exergy analysis. Assessing the exergy efficiency of these processes is key to ensuring the effective deployment of low-carbon hydrogen production technologies. An exergy analysis was performed on an SE-SMR process and was then subsequently used to incorporate process improvements developing a process that has theoretically an extremely high CO2 capture rate of nearly 100 % whilst simultaneously demonstrating a high exergy efficiency (77.58 %) showcasing the potential of blue hydrogen as an effective tool to ensure decarbonisation in an energy-efficient manner.

Combining electrolytic hydrogen production with wind–photovoltaic power can effectively smooth the fluctuation of power and enhance the schedulable wind–photovoltaic power which provides an effective solution to solve the problem of wind–photovoltaic power accommodation. In this paper the optimization operation strategy is studied for the wind–photovoltaic power-based hydrogen production system. Firstly to make up for the deficiency of the existing research on the multi-state and nonlinear characteristics of electrolyzers the three-state and power-current nonlinear characteristics of the electrolyzer cell are modeled. The model reflects the difference between the cold and hot starting time of the electrolyzer and the linear decoupling model is easy to apply in the optimization model. On this basis considering the operation constraints of the electrolyzer hydrogen storage tank battery and other equipment the optimization operation model of the wind–photovoltaic power-based hydrogen production system is developed based on the typical scenario approach. It also considers the cold and hot starting time of the electrolyzer with the daily operation cost as the goal. The results show that the operational benefits of the system can be improved through the proposed strategy. The hydrogen storage tank capacity will have an impact on the operation income of the wind–solar hydrogen coupling system and the daily operation income will increase by 0.32% for every 10% (300 kg) increase in the hydrogen storage tank capacity.

This study reviews existing simulation models and describes a selected model for analysing combustion dynamics in hydrogen and natural gas mixtures specifically within non-ferrous melting furnaces. The primary objectives are to compare the combustion characteristics of these two energy carriers and assess the impact of hydrogen integration on furnace operation and efficiency. Using computational fluid dynamics (CFD) simulations incorporating actual furnace geometries and a detailed combustion and NOx emission prediction model this research aims to accurately quantify the effects of hydrogen blending. Experimental tests on furnaces using only natural gas confirmed the validity of these simulations. By providing precise predictions for temperature distribution and NOx emissions this approach reduces the need for extensive laboratory testing facilitates broader exploration of design modifications accelerates the design process and ultimately lowers product development costs.

The goal of achieving a zero-emission energy system by 2050 requires accurate energy planning to minimise the overall cost of the energy transition. Long-term energy models based on cost-optimal solutions are extremely dependent on the cost forecasts of different technologies. However such forecasts are inherently uncertain. The aim of the present work is to identify a cost-optimal pathway for the Italian energy system decarbonisation and assess how renewable cost scenarios can affect the optimal solution. The analysis has been carried out with the H2RES model a single-objective optimisation algorithm based on Linear Programming. Different cost scenarios for photovoltaics on-shore and off-shore wind power and lithium-ion batteries are simulated. Results indicate that a 100% renewable energy system in Italy is technically feasible. Power-to-X technologies are crucial for balancing purposes enabling a share of non-dispatchable generation higher than 90%. Renewable cost scenarios affect the energy mix however both on-shore and off-shore wind saturate the maximum capacity potential in almost all scenarios. Cost forecasts for lithium-ion batteries have a significant impact on their optimal capacity and the role of hydrogen. Indeed as battery costs rise fuel cells emerge as the main solution for balancing services. This study emphasises the importance of conducting cost sensitivity analyses in long-term energy planning. Such analyses can help to determine how changes in cost forecasts may affect the optimal strategies for decarbonising national energy systems.

The increasing demand for energy and the urgent need to reduce carbon emissions have positioned hydrogen as a promising alternative. This review paper explores the potential of hydrogen blending in natural gas pipelines focusing on the compatibility of pipeline materials and the associated safety challenges. Hydrogen blending can significantly reduce carbon emissions from homes and industries as demonstrated by various projects in Canada and globally. However the introduction of hydrogen into natural gas pipelines poses risks such as hydrogenassisted materials degradation which can compromise the integrity of pipeline materials. This study reviews the effects of hydrogen on the mechanical properties of both vintage and modern pipeline steels cast iron copper aluminum stainless steel as well as plastics elastomers and odorants that compose an active natural gas pipeline network. The review highlights the need for updated codes and standards to ensure safe operation and discusses the implications of hydrogen on material selection design and safety considerations. Overall this manuscript aims to provide a comprehensive resource on the current state of pipeline materials in the context of hydrogen blending emphasizing the importance of further research to address the gaps in current knowledge and to develop robust guidelines for the integration of hydrogen into existing natural gas infrastructure.

The interaction of a shock wave with a specific angle or concave wall due to its reflection and focusing is a way to onset the detonation provided sufficiently strong shock wave. In this work we present numerical simulation results of the detonation initiation due to the shock reflection and focusing in a 90-degree wedge for mixtures of H2 and air. The code used was ddtFoam [1–3] that is a component of the larger OpenFOAM open-source CFD package of density-based code for solving the unsteady compressible Navier-Stokes equations. The numerical model represents the 2-D geometry of the experiments performed by Rudy [4]. The numerical results revealed three potential scenarios in the corner after reflection: shock wave reflection without ignition deflagrative ignition with intermediate transient regimes with a delayed transition to detonation in lagging combustion zone at around 1.8 mm from the apex of the wedge and ignition with an instantaneous transition to detonation with the formation of the detonation wave in the corner tip. In the experimental investigation the transition velocity for the stoichiometric mixture was approximately 715 m/s while in the numerical simulation the transition velocity for the stoichiometric mixture was 675.65 m/s 5.5% decrease in velocity.

The maritime sector plays a crucial role in global trade yet its contribution to greenhouse gas emissions remains significant. The adoption of hydrogen as a clean energy solution is gaining traction to address this. This review paper delves into the opportunities and challenges of integrating hydrogen as a marine fuel. The entire hydrogen supply chain is investigated from production to end use highlighting advancements limitations and potential safety risks. Key findings reveal that while hydrogen offers promise for reducing emissions its widespread adoption requires a well-established production storage and distribution infrastructure. Challenges persist in large-scale storage transportation and bunkering particularly in addressing space limitations and ensuring safety protocols. Propulsion systems such as internal combustion engines gas turbines and fuel cells show po tential for hydrogen adoption yet further research is needed to optimize efficiency and address technical con straints. Safety considerations also appear prominently necessitating comprehensive bunkering operations and hazard management protocols. Addressing knowledge gaps is imperative for successfully integrating hydrogen as a marine fuel. Future research should focus on optimizing storage methods developing efficient propulsion systems and enhancing safety measures to enhance hydrogen utilization in the maritime sector.

The transition to cleaner energy sources particularly in hard-to-abate industrial sectors often requires the gradual integration of new technologies. Hydrogen crucial for decarbonization is explored as a fuel in blended combustions. Blending or replacing fuels impacts combustion stability and heat transfer rates due to differing densities. An extensive literature review examines blended combustion focusing on hydrogen/methane mixtures. While industrial burners claim to accommodate up to 20% hydrogen theoretical support is lacking. A novel thermodynamic analysis methodology is introduced evaluating methane/hydrogen combustion using the Wobbe index. The findings highlight practical limitations beyond 25% hydrogen volume necessitating a shift to “totally hydrogen” combustion. Blended combustion can be proposed as a medium-term strategy acknowledging hydrogen’s limited penetration. Higher percentages require burner and infrastructure redesign.

Underground hydrogen storage (UHS) in salt caverns is a sustainable energy solution to reduce global warming. Salt rocks provide an exceptional insulator to store natural hydrogen as they have low porosity and permeability. Nevertheless the salt creeping nature and hydrogeninduced impact on the operational infrastructure threaten the integrity of the injection/production wells. Furthermore the scarcity of global UHS initiatives indicates that investigations on well integrity remain insufficient. This study strives to profoundly detect the research gap and imperative considerations for well integrity preservation in UHS projects. The research integrates the salt critical characteristics the geomechanical and geochemical risks and the necessary measurements to maintain well integrity. The casing mechanical failure was found as the most challenging threat. Furthermore the corrosive and erosive effects of hydrogen atoms on cement and casing may critically put the well integrity at risk. The research also indicated that the simultaneous impact of temperature on the salt creep behavior and hydrogen-induced corrosion is an unexplored area that has scope for further research. This inclusive research is an up-to-date source for analysis of the previous advancements current shortcomings and future requirements to preserve well integrity in UHS initiatives implemented within salt caverns.

Hydrogen is emerging as a promising future energy medium in a wide range of industries. For mobile applica tions it is commonly stored in a gaseous state within high-pressure composite overwrapped pressure vessels (COPVs). The current state of the art pressure vessel technology known as Type V eliminates the internal polymer gas barrier used in Type IV vessels and instead relies on carbon fibre laminate to provide structural properties and prevent gas leakage. Achieving this functionality at high pressure poses several engineering challenges that have thus far prohibited commercial application. Additionally the traditional manufacturing process for COPVs filament winding has several constraints that limit the design space. Automated fibre placement (AFP) a highly flexible robotic composites manufacturing technique has the potential to replace filament winding for composite pressure vessel manufacturing and provide pathways for further vessel optimi sation. A combination of both AFP and Type V technology could provide an avenue for a new generation of highperformance composite pressure vessels. This critical review presents key work on industry-standard Type IV vessels alongside the current state of Type V CPV technology including manufacturing developments challenges cost relevance to commercial standards and future fabrication solutions using AFP. Additionally a novel Type V CPV design concept for a two-piece AFP produced vessel is presented.

This study investigated the cost competitiveness using total cost of ownership (TCO) analysis of hydrogen fuel cell electric vehicles (FCEVs) in heavy duty on and off-road fleet applications as a key enabler in the decarbonisation of the transport sector and compares results to battery electric vehicles (BEVs) and diesel internal combustion engine vehicles (ICEVs). Assessments were carried out for a present day (2021) scenario and a sensitivity analysis assesses the impact of changing input parameters on FCEV TCO. This identified conditions under which FCEVs become competitive. A future outlook is also carried out examining the impact of time-sensitive parameters on TCO when net zero targets are to be reached in the UK and EU. Several FCEVs are cost competitive with ICEVs in 2021 but not BEVs under base case conditions. However FCEVs do have potential to become competitive with BEVs under specific conditions favouring hydrogen including the application of purchase grants and a reduced hydrogen price. By 2050 a number of FCEVs running on several hydrogen scenarios show a TCO lower than ICEVs and BEVs using rapid chargers but for the majority of vehicles considered BEVs remain the lowest in cost unless specific FCEV incentives are implemented. This paper has identified key factors hindering the deployment of hydrogen and conducted comprehensive TCO analysis in heavy duty on and off-road fleet applications. The output has direct contribution to the decarbonisation of the transport sector.