Publications

Proton exchange membrane fuel cells (PEMFCs) are promising clean energy conversion devices in residential transportation and portable applications. Currently a high-pressure tank is the state-of-the-art mode of hydrogen storage; however the energy cost safety and portability (or volumetric hydrogen storage capacity) presents a major barrier to the widespread dissemination of PEMFCs. Here we show an ‘all-polymer type’ rechargeable PEMFC (RCFC) that contains a hydrogen-storable polymer (HSP) which is a solid-state organic hydride as the hydrogen storage media. Use of a gas impermeable SPP-QP (a polyphenylenebased PEM) enhances the operable time reaching up to ca. 10.2 s mg_HSP ⁻¹ which is more than a factor of two longer than that (3.90 s mg_HSP ⁻¹) for a Nafion NRE-212 membrane cell. The RCFCs are cycleable at least up to 50 cycles. The features of this RCFC system including safety ease of handling and light weight suggest applications in mobile light-weight hydrogen-based energy devices.

The key direction of political actions in the field of sustainable development of the energy sector and economy is the process of energy transformation (decarbonization) and increasing the share of renewable energy sources (RES) in the supply of primary energy. Regardless of the indisputable advantages RES are referred to as unstable energy sources. A possible solution might be the development of the concept of hydrogen supply chains especially the so-called green hydrogen obtained in the process of electrolysis from electricity produced from RES. The aim of the research undertaken in the article is to identify the scope of research carried out in the area of hydrogen supply chains and to link this research with the issues of the operation of electricity distribution networks powered by RES. As a result of the scoping review and the application of the text-mining method using the IRaMuTeQ tool which includes the analysis of the content of 12 review articles presenting the current research achievements in this field over the last three years (2016–2020) it was established that the issues related to hydrogen supply chains including green hydrogen are still not significantly associated with the problem of the operation of power grids. The results of the conducted research allow formulating recommendations for further research areas.

Governments around the world are leveraging unprecedented amounts of capital to respond to the pandemic and bailing out struggling industries. Trends in energy-related spending indicate that despite the green push the world’s largest economies have still favoured fossil energy over clean energy.<br/><br/>We evaluate energy-related spending in Canada in 2020 (since the onset of COVID-19) using data from the Energy Policy Tracker. Trends in Canada are then compared to flagship policies in key jurisdictions with recent progressive climate policy announcements including France Germany and the United Kingdom. The brief ends with broad recommendations on how Canada can better align its recovery funding with climate action and fossil fuel subsidy reform.<br/><br/>This brief is one of three International Institute for Sustainable Development (IISD) policy briefs in its Recovery Through Reform series which assesses how efforts to achieve a green recovery from COVID-19 in Canada rely on—and can contribute to—fossil fuel subsidy reform.

Fuel cell technologies have several applications in stationary power production such as units for primary power generation grid stabilization systems adopted to generate backup power and combined-heat-and-power configurations (CHP). The main sectors where stationary fuel cells have been employed are (a) micro-CHP (b) large stationary applications (c) UPS and IPS. The fuel cell size for stationary applications is strongly related to the power needed from the load. Since this sector ranges from simple backup systems to large facilities the stationary fuel cell market includes few kWs and less (micro-generation) to larger sizes of MWs. The design parameters for the stationary fuel cell system differ for fuel cell technology (PEM AFC PAFC MCFC and SOFC) as well as the fuel type and supply. This paper aims to present a comprehensive review of two main trends of research on fuel-cell-based poly-generation systems: tracking the market trends and performance analysis. In deeper detail the present review will list a potential breakdown of the current costs of PEM/SOFC production for building applications over a range of production scales and at representative specifications as well as broken down by component/material. Inherent to the technical performance a concise estimation of FC system durability efficiency production maintenance and capital cost will be presented.

Fracture failure caused by hydrogen embrittlement (HE) is a major concern for the system reliability and safety of hydrogen storage vessels which are generally made of 2.25Cr1Mo0.25V steel. Thus study of the influence of pre-charged hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld is of significant importance. In the current work the influence of hydrogen on fracture toughness of as-received 2.25Cr1Mo0.25V steel and weld was systematically studied. Base metal (BM) and weld metal (WM) specimens under both hydrogen-free and hydrogen-charged conditions were tested using three-point bending tests. Hydrogen was pre-charged inside specimens by the immersion charging method. The J-integral values were calculated for quantitatively evaluating the fracture toughness. In order to investigate the HE mechanisms optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the microstructure of BM and WM specimens. The results revealed that the presence of pre-charged hydrogen caused a significant decrease of the fracture toughness for both BM and WM specimens. Moreover the pre-charged hydrogen led to a remarkable transition of fracture mode from ductile to brittle pattern in 2.25Cr1Mo0.25V steel.

Hydrogen embrittlement (HE) is a critical issue that hinders the reliability of hydrogenation reactors. Hence it is of great significance to investigate the effect of hydrogen on fracture toughness of 2.25Cr-1Mo-0.25V steel and weld. In this work the fracture behavior of 2.25Cr-1Mo-0.25V steel and welds was studied by three-point bending tests under hydrogen-free and hydrogen-charged conditions. The immersion charging method was employed to pre-charge hydrogen inside specimen and the fracture toughness of these joints was evaluated quantitatively. The microstructure and grain size of the specimens were observed by scanning electron microscopy (SEM) and by metallurgical microscopy to investigate the HE mechanisms. It was found that fracture toughness for both the base metal (BM) and the weld zone (WZ) significantly decreased under hydrogen-charged conditions due to the coexistence of the hydrogen-enhanced decohesion (HEDE) and hydrogen-enhanced localized plasticity (HELP) mechanisms. Moreover the formation and growth of primary voids were observed in the BM leading to a superior fracture toughness. In addition the BM compared to the WZ shows superior resistance to HE because the finer grain size in the BM leads to a larger grain boundary area thus distributing more of the diffusive hydrogen trapped in the grain boundary and reducing the hydrogen content.

In the research the corrosion and mechanical properties as well as susceptibility to hydrogen embrittlement of two casing pipe steels were investigated in order to assess their serviceability in corrosive and hydrogenating environments under operation in oil and gas wells. Two carbon steels with different microstructures were tested: the medium carbon steel (MCS) with bainitic microstructure and the medium-high carbon steel (MHCS) with ferrite–pearlite microstructure. The results showed that the corrosion resistance of the MHCS in CO2-containing acid chloride solution simulating formation water was significantly lower than that of the MCS which was associated with microstructure features. The higher strength MCS with the dispersed microstructure was less susceptible to hydrogen embrittlement under preliminary electrolytic hydrogenation than the lower strength MHCS with the coarse-grained microstructure. To estimate the embrittlement of steels the method of the FEM load simulation of the specimens with cracks was used. The constitutive relations of the true stress–strain of the tested steels were defined. The stress and strain dependences in the crack tip were calculated. It was found that the MHCS was characterized by the lower plasticity on the stage of the neck formation of the specimen and the lower fracture toughness than the other one. The obtained results demonstrating the limitations of the usage of casing pipes made of the MHCS with the coarse-grained ferrite/pearlite microstructure in corrosive and hydrogenating environments were discussed.

The Australian transport sector is under increasing pressure to reduce carbon emissions whilst also managing a fuel supply chain that relies heavily on foreign import partners.



Transport in Australia equates to a significant proportion (approximately 18%) of the country’s total greenhouse gas emissions. Due to ongoing population growth these emissions have been steadily rising with the increase of cars on our roads and freight trucks in transit. Coupled with this the transport fuel supply chain is highly reliant on overseas partners – Australia currently imports 90% of its liquid fuel. These two challenges present an interesting dichotomy for the industry incentivising research and development into new technologies that can address one or both of these issues.



Hydrogen is one technology that has the potential to provide a reduction in greenhouse gas emissions as well as a more reliable domestic fuel supply. Hydrogen fuel cell electric vehicles (FCEVs) are an emerging zero-emission alternative for the transport sector which offer a variety of benefits.



You can read the full report on the Aurecon Australasia website at this link

Hydrogen assisted macrodelamination in the pipe elbows of 40-year exploited lateral pipelines located behind the compressor station was studied. The crack on the external surface of the pipe elbow was revealed. Macrodelamination was occurred in the steel being influenced by the joined action of working loads and hydrogen absorbed by metal during long-term operation. The causes of the material degradation were investigated by non-destructive testing using ultrasound thickness meter observing microstructure hydrostatic pressure testing and mechanical properties testing of pipe steel.<br/>Intensive degradation of steel primarily essential reduction of plasticity was revealed. The degradation degree of the pipe elbow steel was higher than of the straight pipe steel regardless of a section was tensioned or compressed. Basing on the tensile tests carried out on cylindrical smooth and notched specimens from the pipe elbow steel it was established that the plasticity of the damaged steel could be measured correctly only on the specimens with a circular notch due to concentration of deformation in the cross section location only. The limitations in using elongation and reduction in area for characterisation of plasticity of the pipe steel with extensive delamination were defined. The diagnostic features of macrodelamination namely an abnormal thickness meter readings and a sharp decrease in hardness and plasticity of the pipe elbow steel were established.

This work reports a numerical investigation of microcombustion in an undulate microchannel using premixed hydrogen and air to understand the effect of the burner design on the flame in order to obtain stability of the flame. The simulations were performed for a fixed equivalence ratio and a hyperbolic temperature profile imposed at the microchannel walls in order to mimic the heat external losses occurred in experimental setups. Due to the complexity of the flow dynamics combined with the combustion behavior the present study focuses on understanding the effect of the fuel inlet rate on the flame characteristics keeping other parameters constant. The results presented stable flame structure regardless of the inlet velocity for this type of design meaning that a significant reduction in the heat flux losses through the walls occurred allowing the design of new simpler systems. The increase in inlet velocity increased the flame extension with the flame being stretched along the microchannel. For higher velocities flame separation was observed with two detected different combustion zones and the temperature profiles along the burner centerline presented a non-monotonic decrease due to the dynamics of the vortices observed in the convex regions of the undulated geometry walls. The geometry effects on the flame structure flow field thermal evolution and species distribution for different inlet velocities are reported and discussed.

This article explains and evaluates contemporary methods for manufacturing bipolar plates (BPPs) for lowtemperature polymer electrolyte membrane fuel cells (LT-PEMFC) and highlights the potential of new improved approaches. BPPs are an essential component of fuel cells responsible for distributing reaction gases to facilitate efficient conversion of gaseous electrochemical energy to electricity. BPPs must balance technical properties such as electrical and thermal conductivities structural strength and corrosion resistance. Graphitic and metallic materials can meet the required specifications with each material offering distinct advantages and disadvantages. Each materials’ performance is complimented by a comparison of its manufacturability including: the material costs production rates and required capital investment. These results are contextualised with respect to the target applications to identify the challenges and advantages of manufacturing methods of choice for BPPs. This analysis shows that the optimal choice of BPP manufacturing method depends entirely on the needs of the target application in particular the relative importance of manufacturing rate cost and the expected operational life of the bipolar plate to the fuel cell designer.

The Australian transport sector is under increasing pressure to reduce carbon emissions whilst also managing a fuel supply chain that relies heavily on foreign import partners.



Transport in Australia equates to a significant proportion (approximately 18%) of the country’s total greenhouse gas emissions. Due to ongoing population growth these emissions have been steadily rising with the increase of cars on our roads and freight trucks in transit. Coupled with this the transport fuel supply chain is highly reliant on overseas partners – Australia currently imports 90% of its liquid fuel. These two challenges present an interesting dichotomy for the industry incentivising research and development into new technologies that can address one or both of these issues.



Hydrogen is one technology that has the potential to provide a reduction in greenhouse gas emissions as well as a more reliable domestic fuel supply. Hydrogen fuel cell electric vehicles (FCEVs) are an emerging zero-emission alternative for the transport sector which offer a variety of benefits.



Available from the Energy Ministers Website link here

In comparison with the power sector large scale decarbonisation of heat has received relatively little attention at the infrastructural scale despite its importance in the global CO2 emissions landscape. In this study we focus on the regional transition of a heating sector from natural gas-based infrastructure to H2 using mathematical optimisation. A discrete spatio-temporal description of the geographical region of Great Britain was used in addition to a detailed description of all network elements for illustrating the key factors in the design of nation-wide H2 and CO2 infrastructure. We have found that the synergistic deployment of H2 production technologies such as autothermal reforming of methane and biomass gasification with CO2 abatement technologies such as carbon capture and storage (CCS) are critical in achieving cost-effective decarbonisation. We show that both large scale underground H2 storage and water electrolysis provide resilience and flexibility to the heating system competing on cost and deployment rates. The optimal regions for siting H2 production infrastructure are characterised by proximity to: (1) underground H2 storage (2) high demands for H2 (3) geological storage for CO2. Furthermore cost-effective transitions based on a methane reforming pathway may necessitate regional expansions in the supply of natural gas with profound implications for security of supply in nations that are already highly reliant potentially creating an infrastructure lock-in during the near term. We found that the total system cost comprising both investment and operational elements is mostly influenced by the natural gas price followed by biomass price and CapEx of underground caverns. Under a hybrid Regulated Asset Base (RAB) commercial framework with private enterprises delivering production infrastructure the total cost of heat supply over the infrastructure lifetime is estimated as 5.2–8.6 pence per kW h. Due to the higher cost relative to natural gas a Contract for Difference payment between d20 per MW h and d53 per MW h will be necessary for H2-derived heat to be competitive in the market.

The aim of the work is a numerical estimation of the conditional probability of damage to the mine personnel during an accidental explosion of a hydrogen-air mixture. The methodology for determining the parameters of the gas-dynamic process of the explosion of a hydrogen-air cloud in an open and closed space taking into account chemical interaction and space clutter is presented. A computational method based on a probit analysis for determining the damage probability fields of a person exposed to the explosion shock wave has been developed. To automate the computational process the tabular dependence “probit-function-damage probability” is replaced by a piecewise cubic spline. Numerical studies of the influence of the drift working space clutter by an electric locomotive on the distribution of the overpressure of the gaseous medium and the conditional probability of the eardrums rupture and lethal damage to personnel in the accidental zone of the coal mine have been carried out. It was obtained that the closed nature of the working space and its blockage significantly changes the shape and size of the danger zone and requires consideration by an expert at the stage of deciding on the safety level at the mine. The scientific novelty of the method proposed in the work is in taking into account in the mathematical model of the movement of a multi-component chemically reacting gas mixture the effect of compressibility of flow complex terrain (space clutter with equipment) three-dimensional nature of the gas-air mixture dispersion process. The model allows obtaining the space-time distributions of the shock-impulse load of the blast wave that is necessary for determining the non-stationary three-dimensional fields of the conditional probability of damage to the staff on the basis of probit analysis. The developed computational method allows analyzing and forecasting in time and space the conditional probability of damage of varying degrees of severity of personnel who are exposed to an explosive shock wave as an indicator of the safety level of a coal mine.

This paper studies the economic feasibility of installing hydrogen networks for decarbonizing heat in urban areas. The study uses the Heat Infrastructure and Technology (HIT) spatially resolved optimization model to trade-off energy supply infrastructure and end-use technology costs for the most important heat-related energy vectors: gas heat electricity and hydrogen. Two model formulations are applied to a UK urban area: one with an independent hydrogen network and one that allows for retrofitting the gas network into hydrogen. Results show that for average hydrogen price projections cost-effective pathways for heat decarbonization toward 2050 include heat networks supplied by a combination of district-level heat pumps and gas boilers in the domestic and commercial sectors and hydrogen boilers in the domestic sector. For a low hydrogen price scenario when retrofitting the gas network into hydrogen a cost-effective pathway is replacing gas by hydrogen boilers in the commercial sector and a mixture of hydrogen boilers and heat networks supplied by district-level heat pumps gas and hydrogen boilers for the domestic sector. Compared to the first modelled year CO₂ emission reductions of 88% are achieved by 2050. These results build on previous research on the role of hydrogen in cost-effective heat decarbonization pathways.

This is a Network Innovation Allowance funded project overseen by a steering group comprising the UK and Ireland gas network operators (Cadent Gas Networks Ireland National Grid Northern Gas Networks SGN Wales and West). The project follows on from previous studies that modelled the role of green gases in decarbonising the GB economy. The role of this study is to understand the transition from the GB economy today to a decarbonised economy in 2050 focusing on how the transition is achieved and the competing and complementary nature of different low and zero emission fuels and technologies over time.

While the project covers the whole economy it focuses on  transport especially trucks as an early adopter of green gases and as a key enabler of the transition. The study and resulting report are aimed at the gas industry and government and tries to build a green gas decarbonisation narrative supported by a wide range of stakeholders in order clarify the path ahead and thereby focus future efforts on delivering decarbonisation through green gases as quickly as possible.

The objectives of the study are:

• Analyse the complete supply chain production distribution and use of electricity biomethane bio-SNG and hydrogen to understand the role of each fuel and the timeline for scaling up of their use.
• Develop a narrative based on these findings to show how the use of these fuels scales up over time and how they compete and complement one another.

Once a clear narrative to 2050 was developed put togethera series of policy asks and stakeholder actions to show what is required to achieve the narrative. The study included analysis of two scenarios a High Green Gas scenario and a Low Green Gas scenario. The narrative presented here focuses on the High Green Gas scenario with commentary on the Low Green Gas scenario covered in Chapter 6.

Green gases

This report discusses the future role of ‘green gases’ which are biomethane and hydrogen produced from low- and zero-carbon sources each produced via two main methods:

Biomethane from Anaerobic Digestion (AD): A mature technology for turning biological material into a non-fossil form of natural gas (methane). AD plants produce biogas which must then be upgraded to biomethane.

Biomethane from Bio-Substitute Natural Gas (Bio-SNG): This technology is at an earlier stage of development than AD but has the potential to unlock other feedstocks for biomethane production such as waste wood and residual household waste.

Blue Hydrogen: Hydrogen from reformation of natural gas which produces hydrogen and carbon monoxide. 90-95% of the carbon is captured and stored making this a low-carbon form of hydrogen.

Green Hydrogen: Water is split into hydrogen and oxygen via electrolysis using electricity generated by renewables. No carbon emissions are produced so this is zero-carbon hydrogen."

This manuscript presents the results of a multi-lateral international activity intended to understand how to execute a cycle stress test as specified in a chosen standard (GTR SAE ISO EIHP …). The purpose of this work was to establish a harmonized test method protocol to ensure that the same results would be achieved regardless of the testing facility. It was found that accurate temperature measurement of the working fluid is necessary to ensure the test conditions remain within the tolerances specified. Continuous operation is possible with adequate cooling of the working fluid but this becomes more demanding if the cycle frequency increases. Recommendations for future test system design and operation are presented.

Transitioning from fossil fuels to sustainable and green energy sources in mobile applications is a difficult challenge and demands sustained and highly multidisciplinary efforts in R&D. Liquid organic hydrogen carriers (LOHC) offer several advantages over more conventional energy storage solutions but have not been yet demonstrated at scale. Herein we describe the development of an integrated and compact 25 kW formic acid-to-power system by a team of BSc and MSc students. We highlight a number of key engineering challenges encountered during scale-up of the technology and discuss several aspects commonly overlooked by academic researchers. Conclusively we provide a critical outlook and suggest a number of developmental areas currently inhibiting further implementation of the technology.

Hydrogen is expected to be a next-generation energy source that does not emit carbon dioxide but when used as a fuel the issue is the increase in the amount of NOx that is caused by the increase in flame temperature. In this study we experimentally investigated NOx emissions rate when hydrogen was burned in a hydrocarbon gas burner which is used in a wide temperature range. As a result of the experiments the amount of NOx when burning hydrogen in a nozzle mixed burner was twice as high as when burning city gas. However by increasing the flow velocity of the combustion air the amount of NOx could be reduced. In addition by reducing the number of combustion air nozzles rather than decreasing the diameter of the air nozzles a larger recirculation flow could be formed into the furnace and the amount of NOx could be reduced by up to 51%. Furthermore the amount of exhaust gas recirculation was estimated from the reduction rate of NOx and the validity was confirmed by the relationship between adiabatic flame temperature and NOx calculated from the equilibrium calculation by chemical kinetics simulator software.

When looking out to 2050 there is huge uncertainty surrounding how gas will be consumed transported and sourced in Great Britain (GB). The extent of the climate change challenge is now widely accepted and the UK Government has introduced a legislative requirement for aggressive reductions in carbon dioxide (CO2) emissions out to 2050. In addition at European Union (EU) level a package of measures has been implemented to reduce greenhouse gas emissions improve energy efficiency and significantly increase the share of energy produced from renewable sources by 2020. These policy developments naturally raise the question of what role gas has to play in the future energy mix.



To help inform this debate the Energy Networks Association Gas Futures Group (ENA GFG) commissioned Redpoint and Trilemma to undertake a long-range scenario-based modelling study of the future utilisation of gas out to 2050 and the consequential impacts of this for gas networks. Our modelling assumptions draw heavily on the Department of Energy and Climate Change (DECC) 2050 Pathways analysis and we consider that our conclusions are fully compatible with both DECC‟s work and current EU policy objectives.



Link to document

Hydrogen embrittlement which severely affects structural materials such as steel comprises several mechanisms at the atomic level. One of them is hydrogen enhanced decohesion (HEDE) the phenomenon of H accumulation between cleavage planes where it reduces the interplanar cohesion. Grain boundaries are expected to play a significant role for HEDE since they act as trapping sites for hydrogen. To elucidate this mechanism we present the results of first-principles studies of the H effect on the cohesive strength of α-Fe single crystal (001) and (111) cleavage planes as well as on the Σ5(310)[001] and Σ3(112)[11¯0] symmetrical tilt grain boundaries. The calculated results show that within the studied range of concentrations the single crystal cleavage planes are much more sensitive to a change in H concentration than the grain boundaries. Since there are two main types of procedures to perform ab initio tensile tests different in whether or not to allow the relaxation of atomic positions which can affect the quantitative and qualitative results these methods are revisited to determine their effect on the predicted cohesive strength of segregated interfaces

Safety is an essential element for realizing the “hydrogen economy” – safe operation in all of its aspects from hydrogen production through storage distribution and use; from research development and demonstration to commercialization. As such safety is given paramount importance in all facets of the research development and demonstration of the U.S Department of Energy’s (DOE) Hydrogen Fuel Cells and Infrastructure Technologies (HFCIT) Program Office. The diversity of the DOE project portfolio is self-evident. Projects are performed by large companies small businesses DOE National Laboratories academic institutions and numerous partnerships involving the same. Projects range from research exploring advances in novel hydrogen storage materials to demonstrations of hydrogen refuelling stations and vehicles. Recognizing the nature of its program and the importance of safety planning DOE has undertaken a number of initiatives to encourage and shape safety awareness. The DOE Hydrogen Safety Review Panel was formed to bring a broad cross-section of expertise from the industrial government and academic sectors to help ensure the success of the program as a whole. The Panel provides guidance on safety-related issues and needs reviews individual DOE-supported projects and their safety plans and explores ways to bring learnings to broadly benefit the DOE program. This paper explores the approaches used for providing safety planning guidance to contractors in the context of their own (and varied) policies procedures and practices. The essential elements that should be included in safety plans are described as well as the process for reviewing project safety plans. Discussion of safety planning during the conduct of safety review site visits is also shared. Safety planning-related learnings gathered from project safety reviews and the Panel’s experience in reviewing safety plans are discussed.

Today it is not known – neither qualitatively not quantitatively - how large the impact can be of the promoters on sensitivity to hydrogen-air detonation in hypothetical accidents at hydrogen-containing installations transport or storage facilities. Report goal is to estimate theoretically an effect of hydrogen-peroxide (as representative promoter) on sensitivity to detonation of the stoichiometric hydrogen-oxygen gas mixtures. The classical H₂-O2-Ar (2:1:7) gas mixture was chosen as reference system with the well established and unambiguously interpreted experimental data. In kinetic simulations it was found that the ignition delay time is sensitive to H₂O₂addition for small initial H₂O₂concentrations and is nearly constant for the large ones. Parametric reactive CFD studies of two dimensional cellular structure of 2H₂-O₂-7Ar-H₂O₂ detonations with variable hydrogen peroxide concentration (up to 10 vol.%) were also performed. Two un-expected results were obtained. First result: detonation cell size is practically independent upon variation of initial hydrogen peroxide concentration. For practical applications it means that presence of hydrogen-peroxide did not change drastically sensitivity of the stoichiometric hydrogen-oxygen gas mixtures. These theoretical speculations require an experimental verification. Second result: for large enough initial H₂O₂concentrations (> 1 vol.% at least) a new element of cellular structure of steady detonation wave was revealed. It is a system of multiple secondary longitudinal shock waves (SLSW) which propagates in the direction opposite to that of the leading shock wave. Detailed mechanism of SLSW formation is proposed.

Hydrogen fuel cell vehicles are expected to come into widespread use in the near future. Accordingly many hydrogen carrying vehicles will begin to pass through tunnels. It is therefore important to predict whether risk from leaked hydrogen accidents in tunnels can be avoided. CFD simulation was carried out on diffusion  of leaked hydrogen in tunnels. Three areas of tunnels were chosen for study. One is the typical longitudinal and lateral areas of tunnels and the others are underground ventilation facilities and electrostatic dust collectors which were simulated with an actual tunnel. The amount of hydrogen leaked was 60m3 (approximately 5.08 kg) which corresponds to the amount necessary for future fuel cell vehicles to achieve their desired running distance. Analytical periods were the time after leaks began until regions of hydrogen above the low flammability limit had almost disappeared or thirty minutes. We found that leaked hydrogen is immediately carried away from leaking area under existing ventilation conditions. We also obtained basic data on behaviour of leaked hydrogen.

This paper shows the experimental results and findings of field explosion tests conducted to obtain fundamental data concerning the explosion of hydrogen-air mixtures. A tent covered with thin plastic sheets was filled with hydrogen/air mixed gas and subsequently ignited by an electric-spark or explosives to induce deflagration and/or detonation. Several experiments with different concentrations and/or volumes of mixture were carried out. The static overpressure of blast waves was measured using piezoelectric pressure sensors. The recorded data show that the shape of the pressure-time histories of the resulting blast waves depends on the difference in the ignition method used. The pictures of the explosion phenomenon (deflagration and/or detonation) were taken by high-speed cameras.