Publications

Nickel-based catalysts recognized for their cost-efficiency and availability play a critical role in advancing hydrogen production technologies. This study evaluates their optimization in water electrolysis to improve efficiency and system stability. Key findings highlight the enhancement of these catalysts with nickel-iron oxyhydroxide and nickel-molybdenum co-catalysts. Technological innovations such as Perovskite Solar Cells integration for solar-to-hydrogen conversion are explored. The use of nickel foam enhances electrode durability offering valuable insights into designing sustainable and efficient hydrogen production systems.

The fuel cell electric vehicle (FCEV) is a promising transportation technology for resolving the air pollution and climate change issues in the United States. However a large-scale penetration of FCEVs would require a sustained supply of hydrogen which does not exist now. Water electrolysis can produce hydrogen reliably and sustainably if the electricity grid is clean but the impacts of FCEVs on the electricity grid are unknown. In this paper we develop a comprehensive framework to model FCEV-driving and -refueling behaviors the water electrolysis process and electricity grid operation. We chose the Western Electricity Coordinating Council (WECC) region for this case study. We modeled the existing WECC electricity grids and accounted for the additional electricity loads from FCEVs using a Production Cost Model (PCM). Additionally the hydrogen need for five million FCEVs leads to a 3% increase in electricity load for WECC. Our results show that an inflexible hydrogen-producing process leads to a 1.55% increase to the average cost of electricity while a flexible scenario leads to only a 0.9% increase. On the other hand oversized electrolyzers could take advantage of cheaper electricity generation opportunities thus lowering total system costs.

The shift to renewable energy sources requires systems that are not only environmentally sustainable but also cost-effective and reliable. Mitigating the inherent intermittency of renewable energy optimally managing the hybrid energy storage efficiently integrating the microgrid with the power grid and maximizing the lifespan of system components are the significant challenges that need to be addressed. With this aim the paper proposes an economic viability assessment framework with an optimized dynamic operation approach to determine the most stable cost-effective and environmentally sound system for a specific location and demand. The green integrated hybrid microgrid combines photovoltaic (PV) generation battery storage an electrolyzer a hydrogen tank and a fuel cell tailored for deployment in remote areas with limited access to conventional infrastructure. The study’s control strategy focuses on managing energy flows between the renewable energy resources battery and hydrogen storage systems to maximize autonomy considering real-time changes in weather conditions load variations and the state of charge of both the battery and hydrogen storage units. The core system’s components include the interlinking converter which transfers power between AC and DC grids and the decentralized droop control approach which adjusts the converter’s output to ensure balanced and efficient power sharing particularly during overload conditions. A cloud-based Internet of Things (IoT) platform has been employed allowing continuous monitoring and data analysis of the green integrated microgrid to provide insights into the system's health and performance during the dynamic operation. The results presented in this paper confirmed that the proposed framework enabled the strategic use of energy storage particularly hydrogen systems. The optimal operational control of green hydrogen-integrated microgrid can indeed mitigate voltage and frequency fluctuations caused by variable solar input ensuring stable power delivery without reliance on the main grid or fossil fuel backups.

The study presents a complete one-dimensional model to evaluate the parameters that describe the operation of a Proton Exchange Membrane (PEM) electrolyzer and PEM fuel cell. The mathematical modeling is implemented in Matlab/Simulink® software to evaluate the influence of parameters such as temperature pressure and overpotentials on the overall performance. The models are further merged into an integrated electrolyzer-fuel cell system for electrical power generation. The operational description of the integrated system focuses on estimating the overall efficiency as a novel indicator. Additionally the study presents an economic assessment to evaluate the cost-effectiveness based on different economic metrics such as capital cost electricity cost and payback period. The parametric analysis showed that as the temperature rises from 30 to 70 C in both devices the efficiency is improved between 5-20%. In contrast pressure differences feature less relevance on the overall performance. Ohmic and activation overpotentials are highlighted for the highest impact on the generated and required voltage. Overall the current density exhibited an inverse relation with the efficiency of both devices. The economic evaluation revealed that the integrated system can operate at variable load conditions while maintaining an electricity cost between 0.3-0.45 $/kWh. Also the capital cost can be reduced up to 25% while operating at a low current density and maximum temperature. The payback period varies between 6-10 years for an operational temperature of 70 C which reinforces the viability of the system. Overall hydrogen-powered systems stand as a promising technology to overcome energy transition as they provide robust operation from both energetic and economic viewpoints.

Adverse climate change has forced a deeper reflection on the scale of pollution related to human activity including in the aviation industry. As a result fundamental questions have arisen about the characteristics of these pollutants the mechanisms of their formation and potential strategies for reducing them. This paper provides a comprehensive overview of key technical solutions to minimize the environmental impact of aircraft engines. The solutions presented range from fuel innovations to advanced design changes and drive concepts. Particular attention was paid to sustainable aviation fuels (SAFs) which are currently an important element of the environmental strategy regulated by the European Union. It also discusses the potential use of hydrogen as a potential alternative fuel to replace traditional aviation fuels in the long term. The analysis in the article made it possible to characterize in detail possible modifications in the functioning of aircraft engines based both on the current state of technical knowledge and on the anticipated directions of its development which has not been a frequent issue in comprehensive research so far. The analysis shows that the type of raw material used to create SAF has a strong impact on its physical and chemical parameters and the degree of greenhouse gas emissions. This necessitates a broader analysis of the legitimacy of using a given type of fuel from the SAF group in the direction of selected air operations and areas with a higher risk of severe atmospheric pollution. These results provide the basis for further research into sustainable solutions in the aviation sector that can contribute to significantly reducing its impact on climate change.

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.

The global shift toward a green hydrogen economy requires diversifying production beyond the Middle East and North Africa where political logistical and water constraints limit long-term supply. This study provides a comparative socio-economic assessment of Sub-Saharan African and South American countries focusing on their readiness for large-scale green hydrogen development. A Green Economy Index (GEI) was developed integrating political/regulatory efficiency socio-economic status infrastructure and sustainability indicators. In addition public perception was examined through a survey conducted in Nigeria. Results show GEI scores ranging from 0.328 to 0.744 with Germany as the benchmark. Brazil Uruguay and Namibia emerge as the most promising cases due to strong renewable energy potential socio-economic stability and supportive policies though each faces specific challenges such as transport logistics (Brazil and Uruguay) or water scarcity (Namibia). Nigeria demonstrates significant potential but is constrained by weak infrastructure and public safety concerns. Cameroon Angola and Gabon display moderate performance but require policy and investment reforms. By combining macro-level readiness analysis with social acceptance insights the study highlights opportunities and barriers for diversifying global hydrogen supply chains and advancing sustainable energy transitions in emerging regions.

Hydrogen (H2) admixing in Reactivity Controlled Compression Ignition (RCCI) technology engines is touted to enhance indicated efficiency (ITE>50%) optimize combustion and reduce greenhouse gas emissions. However many pending issues remain regarding engine durability nitrogen oxide (NOX) emissions and blending limits. These issues are addressed by employing a novel performance-oriented model which simulates under 3 min combustion physics with similar predictivity (>95% accuracy) as computational fluid dynamic results. This socalled multizone model is parameterized to real-world operating cycles from a dual-fuel mid-speed marine engine. By considering port-fuel injected H2 the simulations show that combustion phasing advances at an average rate of 0.3⁰CA/% H2 accompanied by a peak reduction in methane slip of 80% achievable at 25% H2 energy share. Also engine control oriented issues are addressed by demonstrating either intake temperature or diesel fuel share optimization to negate the drawbacks of combustion harshness and NOX emissions while improving ITE 1–1.5pp over baseline operation.

The present study aims to conduct a thermodynamic analysis of a novel concept that synergistically integrates clean hydrogen and power production with a liquified natural gas (LNG) regasification system. The designed integrated energy system aims to achieve hydrogen production power production liquified natural gas regasification carbon capture storage and in situ recirculation. Hydrogen sulfide (H2S) from industrial waste streams is used as a major feedstock and filtration combustion of H2S is employed as a hydrogen production method. CO2 obtained from the combustion process is liquified and pumped at a high pressure to recirculated back to the CO2 cycle power generation combustion process. The flu gas obtained after expansion on the turbine is condensed and CO2 is captured and pressurized. The entire plant is simulated in the Aspen Plus simulation environment and a comprehensive thermodynamic assessment including the energy and exergy analysis is conducted. Additionally several parametric studies and assessments of various factors influencing the system's performance are conducted. From the sensitivity analyses it is found that at 20% CO2 recirculation the hydrogen production rate decreases by 31.81% when the operating pressure is increased from 0.05 bar to 3 bar. The adiabatic temperature is reduced by 39.72% 35.37% and 32.85% when 50% 60% and 70% CO2 is recirculated in the oxidant stream at an oxygen to natural gas (ONG) ratio of 0.5. The energy and exergy efficiencies of the system are found to be 71.48% and 60.69% respectively. The present system avoids 2571.94 tons/yr of CO2 emissions for clean hydrogen production and 1426.27 tons/yr of CO2 for clean power production which would otherwise be emitted from steam methane reforming and coal gasification.

The temperature rises hydrogen tanks during the fast-filling process could threaten the safety of the hydrogen fuel cell vehicle. In this paper a 2D axisymmetric model of a type III hydrogen for the bus was built to investigate the temperature evolution during the fast-filling process. A test rig was carried out to validate the numerical model with air. It was found significant temperature rise occurred during the filling process despite the temperature of the filling air being cooled down due to the throttling effect. After verification the 2D model of the hydrogen tank was employed to study the temperature distribution and evolution of hydrogen during the fast-filling process. Thermal stratification was observed along the axial direction of the tank. Then the effects of filling parameters were examined and a formula was fitted to predict the final temperature based on the simulated results. At last an effort was paid on trying the improve the temperature distribution by increasing the injector length of the hydrogen tank. The results showed the maximal temperature and mass averaged temperature decreased by 2 K and 3.4 K with the length of the injector increased from 50 mm to 250 mm.

Hydrogen holds an important strategic position in the energy systems of many countries. Many studies have analyzed the acceptance of hydrogen energy technology from the public’s perspective but few have examined it from the corporate perspective. This paper establishes a technology acceptance model and employs structural equation modeling to investigate the factors affecting the acceptance of hydrogen energy technology within enterprises. After conducting questionnaire surveys among employees of energy enterprises electric power companies and new energy vehicle manufacturers the results indicate that while most of the interviewed enterprises have positive attitudes towards hydrogen technology their willingness to develop hydrogen business does not appear to be correspondingly positive. In addition government trust perceived benefit and social influence positively impact corporate acceptability indirectly whereas perceived risk exhibits a negative indirect effect on corporate acceptance. Finally this paper discusses the results of the above studies and makes corresponding policy recommendations.

The article examines the role of green hydrogen in reducing CO2 emissions in the transition to climate neutrality highlighting both its benefits and challenges. It starts by discussing the production of green hydrogen from renewable sources and provides a brief analysis of primary resource structures for energy production in European countries including Romania. Despite progress there remains a significant reliance on fossil fuels in some countries. Economic technologies for green hydrogen production are explored with a note that its production alone does not solve all issues due to complex and costly compression and storage operations. The concept of impure green hydrogen derived from biomass gasification pyrolysis fermentation and wastewater purification is also discussed. Economic efficiency and future trends in green hydrogen production are outlined. The article concludes with an analysis of hydrogen-methane mixture combustion technologies offering a conceptual framework for economically utilizing green hydrogen in the transition to a green hydrogen economy.

This study proposes the SMR Smart Net-Zero City (SSNC) framework—a scalable model for achieving carbon neutrality by integrating Small Modular Reactors (SMRs) renewable energy sources and sector coupling within a microgrid architecture. As deploying renewables alone would require economically and technically impractical energy storage systems SMRs provide a reliable and flexible baseload power source. Sector coupling systems—such as hydrogen production and heat generation—enhance grid stability by absorbing surplus energy and supporting the decarbonization of non-electric sectors. The core contribution of this study lies in its real-time data emulation framework which overcomes a critical limitation in the current energy landscape: the absence of operational data for future technologies such as SMRs and their coupled hydrogen production systems. As these technologies are still in the pre-commercial stage direct physical integration and validation are not yet feasible. To address this the researchers leveraged real-time data from an existing commercial microgrid specifically focusing on the import of grid electricity during energy shortfalls and export during solar surpluses. These patterns were repurposed to simulate the real-time operational behavior of future SMRs (ProxySMR) and sector coupling loads. This physically grounded simulation approach enables highfidelity approximation of unavailable technologies and introduces a novel methodology to characterize their dynamic response within operational contexts. A key element of the SSNC control logic is a day–night strategy: maximum SMR output and minimal hydrogen production at night and minimal SMR output with maximum hydrogen production during the day—balancing supply and demand while maintaining high SMR utilization for economic efficiency. The SSNC testbed was validated through a seven-day continuous operation in Busan demonstrating stable performance and approximately 75% SMR utilization thereby supporting the feasibility of this proxy-based method. Importantly to the best of our knowledge this study represents the first publicly reported attempt to emulate the real-time dynamics of a net-zero city concept based on not-yet-commercial SMRs and sector coupling systems using live operational data. This simulation-based framework offers a forward-looking data-driven pathway to inform the development and control of next-generation carbon-neutral energy systems.

This study conducts a life cycle assessment and exergoenvironmental evaluation of a double-effect vapor absorption chiller (DEAC) with a cooling capacity of 352 kW employing three different energy sources: natural gas biomethane and green hydrogen. The main objectives of this paper are as follows: (i) provide an exergoenvironmental model for DEAC technologies (ii) evaluation of a case-study where a DEAC is used to cover the cooling demand of a specific university building in the Northeast of Brazil and (iii) evaluate the scenario where the DEAC is fed by green hydrogen (GH2) and compare it with conventional energy resources (natural gas and biomethane). In order to develop the exergoenvironmental model two methodologies are essential: a thermodynamic analysis and a Life Cycle Assessment (LCA). The thermodynamic analysis was carried out using the Engineering Equation Solver (EES: 10.998) software. The LCA has been developed through the open-source software openLCA version 1.10.3 with the Ecoinvent 3.7.1 life cycle inventory database whereas the chosen life cycle inventory assessment (LCIA) method was the ReCiPe Endpoint LCA method (Humanitarian medium weighting–H A). The main results indicate that green hydrogen provides a 99.84% reduction in environmental impacts compared to natural gas during the operational phase while biomethane reduces these impacts by 54.21% relative to natural gas. In the context of life cycle assessment (LCA) green hydrogen decreases fossil resource depletion by 18% and climate change-related emissions by 33.16% compared to natural gas. This study contributes to enhancing the understanding of the environmental and exergoenvironmental impacts of a double-effect vapor absorption chiller by varying the fuel usage during the operational phase.

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.

Combustion of hydrogen-enriched natural gas is a valuable short-term strategy for reducing CO2 emissions from high temperature industrial heating. This paper presents several experiments on combustion characteristics and the formation of nitrogen oxides. The experiments included hydrogen contents up to 100% and fuel heat inputs up to 75 kW. Water-cooled lances were used to influence the furnace temperature. The analysis includes the distribution of furnace temperatures the composition of flue gas the cooling capacity of the lances under steady-state operating conditions and OH*-chemiluminescence imaging of the near burner region. The presented results demonstrate the dependence of furnace conditions and NOX formation on various factors such as different air inlet fluxes furnace temperature and fuel composition for constant heat inputs. Efficiency increased by up to 5.5% and significant changes in flame shaped along with a maximum increase in NOX emissions when comparing natural gas to hydrogen was measured at 167%.

The optimization of hybrid renewable multi-generation systems is crucial for enhancing energy efficiency reducing costs and ensuring sustainable power generation. These factors can be significantly affected by system designs optimization methods climate changes and varying energy demands. The optimization of a stand-alone hybrid renewable energy system (HRES) that integrates various combinations of electricity heating cooling hydrogen and freshwater needs has not been reported in a single comprehensive study. Additionally there has been insufficient attention given to the impact of temporal resolution the recovery of excess energy usage and aligning these efforts with the sustainable development goals (SDGs). This study reviews the recent state-of-theart studies on the stand-alone HRES options for meeting electric heating cooling hydrogen electric vehicles and freshwater demands with various combinations. This study further contributes by examining contemporary literature on sizing optimization reliability analysis sensitivity analysis control techniques detailed modelling and techno-environmental-economic features. It also provides justification for selecting configurations suitable for specific geographical locations along with an analysis of the choice of algorithms and power management systems required to meet the various load demands of a self-sufficient community. By highlighting the im provements and potentials of HRES to achieve various United Nations SDGs this review study aims to bridge existing research gaps.

Green hydrogen is a promising energy vector for industrial applications. However hydrogen leaks can occur causing greenhouse effects and posing safety risks for operators and local communities potentially leading to legal liabilities. Industry 4.0 focuses on digital industrial modernization while Industry 5.0 emphasizes collaborative humancentered and sustainable processes. This study developed and analyzed an Industry 5.0 proof of concept as an additional safety layer for hydrogen leak management. The proof of concept was implemented using Raspberry Pi microcomputers integrated computer vision and OpenAI GPT-3 for dynamic email communication. A legal liability analysis for Chile and Spain identified potential challenges in transitioning the system into a marketready product. The findings suggest the system should act as a complementary safety layer rather than a primary detection system to mitigate legal liability risks as operational deployment without full certification and validation could lead to malfunctions. This study illustrated how hydrogen detection and management can be integrated into Industry 5.0 smart systems. With growing global interest in sustainable engineering and AI regulation as reflected in Regulation (EU) 2024/1689 legal considerations over technologies like the one presented in this study are becoming increasingly relevant.

Temporal decomposition methods aim to solve optimisation problems by converting one problem over a large time series into a series of subproblems over shorter time series. This paper introduces one such method where subproblems are defined over a window that moves back and forth repeatedly over the length of the large time series creating a convergent sequence of solutions and mitigating some of the boundary considerations prevalent in other temporal decomposition methods. To illustrate this moving window method it is applied to two models: an energy storage facility trading electricity in a market; and a hydrogen electrolyser powered by renewable electricity produced and potentially stored onsite. The method is simple to implement and it is found that for large optimisation problems it consistently requires less computation time than the base optimisation algorithm used in this study (by factors up to 100 times). In addition it is analytically demonstrated that decomposition methods in which a minimum is attained for each subproblem need not attain a minimum for the overall problem.

The European Union continues to lead global efforts toward climate neutrality by developing a cohesive regulatory and market framework for alternative fuels including renewable hydrogen. This review article critically examines the recent evolution of the EU’s policy landscape specifically for hydrogen as a renewable fuel of non-biological origin (RFNBO) highlighting its growing importance in hard-to-abate sectors such as industry and transportation. We assess the interplay of market-based mechanisms (e.g. EU ETS II) direct mandates (e.g. FuelEU Maritime RED III) and support auction-based measures (e.g. the European Hydrogen Bank) that collectively shape both the demand and the supply of hydrogen as RFNBO fuel. The article also addresses emerging cost capacity and technical barriers—ranging from constrained electrolyzer deployment to complex certification requirements—that hinder large-scale adoption and market rollout. The article aims to discuss advancing and changing regulatory and market environment for the development of infrastructure and market for hydrogen as RFNBO fuel in the EU in 2019–2024. Synthesizing current research and policy developments we propose targeted recommendations including enhanced cross-border coordination and capacity-based incentives to accelerate investment and infrastructure development. This review informs policymakers industry stakeholders and researchers on critical success factors for integrating hydrogen as a cornerstone of the EU’s climate neutrality efforts.

Accidental hydrogen releases from pipelines pose significant risks particularly with the expanding deployment of hydrogen infrastructure. Despite this there has been a lack of thorough investigation into hydrogen leakage from pipelines especially under complex real-world conditions. This study addresses this gap by modeling hydrogen gas dispersion jet fires and explosions based on practical scenarios. Various factors influencing accident consequences such as leak hole size wind speed wind direction and trench presence were systematically examined. The findings reveal that both hydrogen dispersion distance and jet flame thermal radiation distance increase with leak hole size and wind speed. Specifically the longest dispersion and radiation distances occur when the wind direction aligns with the trench which is 110 m where the hydrogen concentration is 4% and 76 m where the radiation is 15.8 kW/m2 in the case of a 325 mm leak hole and wind under 10 m/s. Meanwhile pipelines lacking trenching exhibit the shortest distances 0.17 m and 0.98 m at a hydrogen concentration of 4% and 15.8 kW/m2 radiation with a leak hole size of 3.25 mm and no wind. Moreover under relatively higher wind speeds hydrogen concentration stratification occurs. Notably the low congestion surrounding the pipeline results in an explosion overpressure too low to cause damage; namely the highest overpressure is 8 kPa but this lasts less than 0.2 s. This comprehensive numerical study of hydrogen pipeline leakage offers valuable quantitative insights serving as a vital reference for facility siting and design considerations to eliminate the risk of fire incidents.

China’s coal chemical sector uses coal as both a fuel and feedstock and its increasing greenhouse gas (GHG) emissions are hard to abate by electrification alone. Here we explore the GHG mitigation potential and costs for onsite deployment of green H2 and O2 in China’s coal chemical sector using a lifecycle assessment and techno-economic analyses. We estimate that China’s coal chemical production resulted in GHG emissions of 1.1 gigaton CO2 equivalent (GtCO2eq) in 2020 equal to 9% of national emissions. We project GHG emissions from China’s coal chemical production in 2030 to be 1.3 GtCO2eq ~50% of which can be reduced by using solar or wind power-based electrolytic H2 and O2 to replace coal-based H2 and air separation-based O2 at a cost of 10 or 153 Chinese Yuan (CNY)/tCO2eq respectively. We suggest that provincial regions determine whether to use solar or wind power for water electrolysis based on lowest cost options which collectively reduce 53% of the 2030 baseline GHG emissions at a cost of 9 CNY/tCO2eq. Inner Mongolia Shaanxi Ningxia and Xinjiang collectively account for 52% of total GHG mitigation with net cost reductions. These regions are well suited for pilot policies to advance demonstration projects.

The transition from fossil fuels to the renewable energies (wind solar) is a key factor to face climate change and build a sustainable reliable and secure energy system. To balance the intermittent energy demand and supply affecting the renewable sources the surplus of electrical energy may be converted in hydrogen and then storage in geological formations. While the risks associated to the natural gas storage in the sub-surface are well known from decades those associated with hydrogen underground storage (UHS) are relatively underexplored. This paper presents an inventory of risks related to large H2-storage in depleted gas and oil fields salt caverns and aquifers. Different issues such as integrity and durability of materials H2 leakages and interaction with the reservoir H2 uncontrolled outflow from the wellhead with potential combustion of air-hydrogen mixture (fire and explosion) soil subsidence and induced seismicity are analyzed.

This paper presents work undertaken by the HSE as part of the Hytunnel-CS project a consortium investigating safety considerations for fuel cell hydrogen (FCH) vehicles in tunnels and similar confined spaces. The sudden failure of a pressurised hydrogen vessel was identified as a scenario of concern due to the severity of the consequences associated with such an event. In order to investigate this scenario experimentally HSE designed a bespoke and reusable ‘sudden release’ vessel. This paper presents an overview of the vessel and the results of a series of 13 tests whereby hydrogen was released from the bespoke vessel into a tunnel at pressures up to 65 MPa. The starting pressure and the volume of hydrogen in the vessel were altered throughout the campaign. Four of the tests also included congestion in the tunnel. The tests reliably autoignited. Overpressure measurements and flame arrival times measured with exposed-tip thermocouples enabled analysis of the severity of the events. A high-pressure fast-acting pressure transducer in the body of the vessel showed the pressure decay in the vessel which shows that 90% of the hydrogen was evacuated in between 1.8 and 3.2 ms (depending on the hydrogen inventory). Schlieren flow imagery was also used at the release point of the hydrogen showing the progression of the shock front following initiation of the tests. An assessment of the footage shows an estimated initial velocity of Mach 3.9 at 0.4 m from the release point. Based on this an ignition mechanism is proposed based upon the temperature behind the initial shock front.

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.