United Kingdom
Divergent Consumer Preferences and Visions for Cooking and Heating Technologies in the United Kingdom: Make Our Homes Clean, Safe, Warm and Smart!
Aug 2023
Publication
Decarbonising the global housing stock is imperative for reaching climate change targets. In the United Kingdom hydrogen is currently being tested as a replacement fuel for natural gas which could be used to supply low-carbon energy to parts of the country. Transitioning the residential sector towards a net-zero future will call for an inclusive understanding of consumer preferences for emerging technologies. In response this paper explores consumer attitudes towards domestic cooking and heating technologies and energy appliances of the future which could include a role for hydrogen hobs and boilers in UK homes. To access qualitative evidence on this topic we conducted ten online focus groups (N = 58) with members of the UK public between February and April 2022. The study finds that existing gas users wish to preserve the best features of gas cooking such as speed responsiveness and controllability but also desire the potential safety and aesthetic benefits of electric systems principally induction hobs. Meanwhile future heating systems should ensure thermal comfort ease of use energy efficiency and smart performance while providing space savings and noise reduction alongside demonstrable green benefits. Mixed-methods multigroup analysis suggests divergence between support levels for hydrogen homes which implies a degree of consumer heterogeneity. Foremost we find that domestic hydrogen acceptance is positively associated with interest and engagement with renewable energy and fuel poverty pressures. We conclude that internalising the perspectives of consumers is critical to enabling constructive socio-technical imaginaries for low-carbon domestic energy futures.
Hydrogen Supply Chain and Refuelling Network Design: Assessment of Alternative Scenarios for the Long-haul Road Freight in the UK
Mar 2023
Publication
Shifting from fossil fuels to clean alternative fuel options such as hydrogen is an essential step in decarbonising the road freight transport sector and facilitating an efficient transition towards zero-emissions goods distribution of the future. Designing an economically viable and competitive Hydrogen Supply Chain (HSC) to support and accelerate the widespread adoption of hydrogen powered Heavy Goods Vehicles (H2-HGVs) is however significantly hindered by the lack of the infrastructure required for producing storing transporting and distributing the required hydrogen. This paper focuses on a bespoke design of a hydrogen supply chain and distribution network for the long-haul road freight transportation in the UK and develops an improved end-to-end and spatially-explicit optimisation tool to perform scenario analysis and provide important first-hand managerial and policy making insights. The proposed methodology improves over existing grid-based methodologies by incorporating spatially-explicit locations of Hydrogen Refuelling Stations (HRSs) and allowing further flexibility and accuracy. Another distinctive feature of the method and the analyses carried out in the paper pertains to the inclusion of bulk geographically agnostic as well as geological underground hydrogen storage options and reporting on significant cost saving opportunities. Finally the curve for H2-HGVs penetration levels safety stock period decisions and the transport mode capacity against hydrogen levelized cost at pump have been generated as important policy making tools to provide decision support and insights into cost resilience and reliability of the HSC.
Performance, Emissions, and Economic Analyses of Hydrogen Fuel Cell Vehicles
May 2024
Publication
The transport sector is considered to be a significant contributor to greenhouse gas emissions as this sector emits about one-fourth of global CO2 emissions. Transport emissions contribute toward climate change and have been linked to adverse health impacts. Therefore alternative and sustainable transport options are urgent for decarbonising the transport sector and mitigating those issues. Hydrogen fuel cell vehicles are a potential alternative to conventional vehicles which can play a significant role in decarbonising the future transport sector. This study critically analyses the recent works related to hydrogen fuel cell integration into vehicles modelling and experimental investigations of hydrogen fuel cell vehicles with various powertrains. This study also reviews and analyses the performance energy management strategies lifecycle cost and emissions of fuel cell vehicles. Previous literature suggested that the fuel consumption and well-to-wheel greenhouse gas emissions of hydrogen fuel cell-powered vehicles are significantly lower than that of conventional internal combustion vehicles. Hydrogen fuel cell vehicles consume about 29–66 % less energy and cause approximately 31–80 % less greenhouse gas emissions than conventional vehicles. Despite this the lifecycle cost of hydrogen fuel cell vehicles has been estimated to be 1.2–12.1 times higher than conventional vehicles. Even though there has been recent progress in energy management in hydrogen fuel cell electric vehicles there are a number of technical and economic challenges to the commercialisation of hydrogen fuel cell vehicles. This study presents current knowledge gaps and details future research directions in relation to the research advancement of hydrogen fuel cell vehicles.
Inspection of Coated Hydrogen Transportation Pipelines
Sep 2023
Publication
The growing need for hydrogen indicates that there is likely to be a demand for transporting hydrogen. Hydrogen pipelines are an economical option but the issue of hydrogen damage to pipeline steels needs to be studied and investigated. So far limited research has been dedicated to determining how the choice of inspection method for pipeline integrity management changes depending on the presence of a coating. Thus this review aims to evaluate the effectiveness of inspection methods specifically for detecting the defects formed uniquely in coated hydrogen pipelines. The discussion will begin with a background of hydrogen pipelines and the common defects seen in these pipelines. This will also include topics such as blended hydrogen-natural gas pipelines. After which the focus will shift to pipeline integrity management methods and the effectiveness of current inspection methods in the context of standards such as ASME B31.12 and BS 7910. The discussion will conclude with a summary of newly available inspection methods and future research directions.
Hydrogen Refuelling Station Calibration with a Traceable Gravimetric Standard
Apr 2020
Publication
Of all the alternatives to hydrocarbon fuels hydrogen offers the greatest long-term potential to radically reduce the many problems inherent in fuel used for transportation. Hydrogen vehicles have zero tailpipe emissions and are very efficient. If the hydrogen is made from renewable sources such as nuclear power or fossil sources with carbon emissions captured and sequestered hydrogen use on a global scale would produce almost zero greenhouse gas emissions and greatly reduce air pollutant emissions. The aim of this work is to realise a traceability chain for hydrogen flow metering in the range typical for fuelling applications in a wide pressure range with pressures up to 875 bar (for Hydrogen Refuelling Station - HRS with Nominal Working Pressure of 700 bar) and temperature changes from −40 °C (pre-cooling) to 85 °C (maximum allowed vehicle tank temperature) in accordance with the worldwide accepted standard SAE J2601. Several HRS have been tested in Europe (France Netherlands and Germany) and the results show a good repeatability for all tests. This demonstrates that the testing equipment works well in real conditions. Depending on the installation configuration some systematic errors have been detected and explained. Errors observed for Configuration 1 stations can be explained by pressure differences at the beginning and end of fueling in the piping between the Coriolis Flow Meter (CFM) and the dispenser: the longer the distance the bigger the errors. For Configuration 2 where this distance is very short the error is negligible.
Review of the Status and Prospects of Fiber Optic Hydrogen Sensing Technology
Aug 2023
Publication
With the unprecedented development of green and renewable energy sources the proportion of clean hydrogen (H2 ) applications grows rapidly. Since H2 has physicochemical properties of being highly permeable and combustible high-performance H2 sensors to detect and monitor hydrogen concentration are essential. This review discusses a variety of fiber-optic-based H2 sensor technologies since the year 1984 including: interferometer technology fiber grating technology surface plasma resonance (SPR) technology micro lens technology evanescent field technology integrated optical waveguide technology direct transmission/reflection detection technology etc. These technologies have been evolving from simply pursuing high sensitivity and low detection limits (LDL) to focusing on multiple performance parameters to match various application demands such as: high temperature resistance fast response speed fast recovery speed large concentration range low cross sensitivity excellent long-term stability etc. On the basis of palladium (Pd)-sensitive material alloy metals catalysts or nanoparticles are proposed to improve the performance of fiberoptic-based H2 sensors including gold (Au) silver (Ag) platinum (Pt) zinc oxide (ZnO) titanium oxide (TiO2 ) tungsten oxide (WO3 ) Mg70Ti30 polydimethylsiloxane (PDMS) graphene oxide (GO) etc. Various microstructure processes of the side and end of optical fiber H2 sensors are also discussed in this review.
Prospectivity Analysis for Underground Hydrogen Storage, Taranaki Basin, Aotearoa New Zealand: A Multi-criteria Decision-making Approach
May 2024
Publication
Seasonal underground hydrogen storage (UHS) in porous media provides an as yet untested method for storing surplus renewable energy and balancing our energy demands. This study investigates the technical suitability for UHS in depleted hydrocarbon fields and one deep aquifer site in Taranaki Basin Aotearoa New Zealand. Prospective sites are assessed using a decision tree approach providing a “fast-track” method for identifying potential sites and a decision matrix approach for ranking optimal sites. Based on expert elicitation the most important factors to consider are storage capacity reservoir depth and parameters that affect hydrogen injectivity/withdrawal and containment. Results from both approaches suggest that Paleogene reservoirs from gas (or gas cap) fields provide the best option for demonstrating UHS in Aotearoa New Zealand and that the country’s projected 2050 hydrogen storage demand could be exceeded by developing one or two high ranking sites. Lower priority is assigned to heterolithic and typically finer grained labile and clay-rich Miocene oil reservoirs and to deep aquifers that have no proven hydrocarbon containment.
Energy Storage Strategy - Phase 2
Feb 2023
Publication
This document is phase 2 of the energy storage strategy study and it covers the storage challenges of the energy transition. We start in section 3 by covering historical and current natural gas imports into the UK and what these could look like in the future. In section 4 we explore what demand for hydrogen could look like – this has a high level of uncertainty and future policy decisions will have significant impacts on hydrogen volumes and annual variations. We generated two hydrogen storage scenarios based on National Grid’s Future Energy Scenarios and the Climate Change Committee’s Sixth Carbon Budget to assess the future need for hydrogen storage in the UK. We also looked at an extreme weather scenario resulting from an area of high-pressure settled over the British Isles resulting in very low ambient temperatures an unusually high demand for heating and almost no wind generation. In section 5 we investigate options for hydrogen storage and build on work previously carried out by SGN. We discuss the differences between the properties of hydrogen and natural gas and how this affects line pack and depletion of line pack. We discuss flexibility on the supply and demand side and how this can impact on hydrogen storage. We provide a summary table which compares the various options for storage. In section 5 we explore hydrogen trade and options for import and export. Using information from other innovation projects we also discuss production of hydrogen from nuclear power and the impact of hybrid appliances on gas demand for domestic heat. In section 7 we discuss the outputs from a stakeholder workshop with about 40 stakeholders across industry academia and government. The workshop covered UK gas storage strategy to date hydrogen demand and corresponding storage scenarios to 2050 including consideration of seasonal variation and storage options.
Detailed Assessment of Dispersion for High-pressure H2 in Multi-fuel Environment
Sep 2023
Publication
The MultHyFuel project notably aims to produce the data missing for usable risk analysis and mitigation activity for Hydrogen Refuelling Stations (HRS) in a multi-fuel context. In this framework realistic releases of hydrogen that could occur in representative multi-fuel forecourts were studied. These releases can occur inside or outside fuel dispensers and they can interact with a complex environment notably made of parked cars and trucks. This paper is focused on the most critical scenarios that were addressed by a sub-group through the use of Computational Fluid Dynamics (CFD) modelling. Once the corresponding source terms for hydrogen releases were known two stages are followed:<br/>♦ Model Validation – to evaluate the CFD models selected by the task partners and to evaluate their performance through comparison to experimental data.<br/>♦ Realistic Release Modelling – to perform demonstration simulations of a range of critical scenarios.<br/>The CFD models selected for the Model Validation have been tested against measured data for a set of experiments involving hydrogen releases. Each experiment accounts for physical features that are encountered in the realistic cases. The selected experiments include an under-expanded hydrogen jet discharging into the open atmosphere with no obstacles or through an array of obstacles. Additionally a very different set-up was studied with buoyancy-driven releases inside a naturally ventilated enclosure. The results of the Model Validation exercise show that the models produce acceptable solutions when compared to measured data and give confidence in the ability of the models and the modellers to capture the behaviour of the realistic releases adequately. The Realistic Release Modelling phase will provide estimation of the flammable gas cloud volume for a set of critical scenarios and will be described at the second stage.
Explosion Free in Fire Self-venting (TPRD-less) Composite Tanks: Performance Under Fire Intervention Conditions
Sep 2023
Publication
This paper describes the performance of explosion free in fire self-venting (TPRD-less) composite tanks of Type IV in fires of realistic intensity HRR/A=1 MW/m2 in conditions of first responders’ intervention. This breakthrough safety technology does not require the use of thermally activated pressure relief devices (TPRD). It provides microleaks-no-burst (LNB) performance of high-pressure hydrogen storage tanks in a fire. Two fire intervention strategies are investigated one is the removal of a vehicle with LNB tank from the fire and another is the extinction of the fire. The removal from the fire scenario is investigated for one carbon-carbon and one carbon-basalt double-composite wall tank prototype. The fire extinction scenario is studied for four carbon-basalt prototypes. All six prototypes of 7.5 L volume and nominal working pressure of 70 MPa demonstrated safe release of hydrogen through microchannels of the composite wall after melting a liner. The technology allows fire brigades to apply standard intervention strategies and tactics at the fire scene with hydrogen vehicles if LNB tanks are used in the vehicle.
Deflagrations of Non-uniform Hydrogen/Air Clouds in a Tunnel
Sep 2023
Publication
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.<br/>Hydrogen vehicles typically have a Thermally activated Pressure Release Device (TPRD) providing protection to the on-board storage of the vehicle. Upon activation the content of the vessel is released in a blowdown. The release of this hydrogen gas poses a significant hazard of ignition. The consequences of such an ignition could also be compounded by confinement or congestion.<br/>HSE undertook a series of experiments investigating the consequences of these events by releasing hydrogen into a tunnel and causing ignitions. A sub-section of these tests involved steel structures providing congestion in the tunnel. The mass of hydrogen released into the tunnel prior to ignition was varied by storage pressure (up to 59 MPa) release diameter and ignition delay. The ignition delays were set based on the expected worst-case predicted by pre-simulation models. To assess the consequences overpressure measurements were made down the tunnel walls and for the tests with congestion at the face and rear of the congestion structures. The flame arrival time was also measured using exposed-tip thermocouples resulting in an estimate for flame speed down the tunnel. The measured overpressure and flame extent results are presented and compared against overpressure levels of concern.
Numerical Simulation of Pressure Recovery Phenomenon in Liquid Ammonia Tank
Sep 2023
Publication
A phase transition develops when a pressurised ammonia vessel is vented through a relieve valve or as a result of shell cracking. Significant pressure recovery in the vessel can occur as a consequence of this phase transition following initial depressurisation and may lead to complete vessel failure. It is critical for safety engineering to predict the flash boiling behaviour and pressure dynamics during the depressurization of liquid ammonia tank. This research aims to develop and compare against available experimental data a CFD model that can predict two-phase behaviour of ammonia and resulting pressure dynamics in the storage tank during its venting to the atmosphere. The CFD model is based on the Volume-of-Fluid (VOF) method and Lee evaporation/condensation approach. The numerical simulation demonstrated that liquid ammonia which is initially at equilibrium state begins to boil throughout due to the decrease of its saturation temperature with the pressure drop during tank venting. In order to understand phenomena underlying the pressure recovery this paper analyses dynamics of superheated ammonia formation its swelling vaporisation contribution to gaseous ammonia mass and volume in ullage space and gaseous ammonia venting. Performed in the study quantitative analysis demonstrated that the flash boiling and gaseous ammonia produced by this phase change were the major reasons behind the pressure recovery. The simulation results of flash boiling delay accurately matched the analytical calculation of bubble rise time. The developed CFD model can be used as a contemporary tool for inherently safer design of ammonia tanks and their depressurisation process.
European Hydrogen Train the Trainer Framework for Responders: Outcomes of the Hyresponder Project
Sep 2023
Publication
Síle Brennan,
Didier Bouix,
Christian Brauner,
Dominic Davis,
Natalie DeBacker,
Alexander Dyck,
André Vagner Gaathaug,
César García Hernández,
Laurence Grand-Clement,
Etienne Havret,
Deborah Houssin-Agbomson,
Petr Kupka,
Laurent Lecomte,
Eric Maranne,
Vladimir V. Molkov,
Pippa Steele,
Adolfo Pinilla,
Paola Russo and
Gerhard Schoepf
HyResponder is a European Hydrogen Train the Trainer programme for responders. This paper describes the key outputs of the project and the steps taken to develop and implement a long-term sustainable train the trainer programme in hydrogen safety for responders across Europe and beyond. This FCH2 JU (now Clean Hydrogen Joint Undertaking) funded project has built on the successful outcomes of the previous HyResponse project. HyResponder has developed further and updated educational operational and virtual reality training for trainers of responders to reflect the state-of-the-art in hydrogen safety including liquid hydrogen and expand the programme across Europe and specifically within the 10 countries represented directly within the project consortium: Austria Belgium the Czech Republic France Germany Italy Norway Spain Switzerland and the United Kingdom. For the first time four levels of educational materials from fire fighter through to specialist have been developed. The digital training resources are available on the e-Platform (https://hyresponder.eu/e-platform/). The revised European Emergency Response Guide is now available to all stakeholders. The resources are intended to be used to support national training programs. They are available in 8 languages: Czech Dutch English French German Italian Norwegian and Spanish. Through the HyResponder activities trainers from across Europe have undertaken joint actions which are in turn being used to inform the delivery of regional and national training both within and beyond the project. The established pan-European network of trainers is shaping the future in the important for inherently safer deployment of hydrogen systems and infrastructure across Europe and enhancing the reach and impact of the programme.
The Global Shift to Hydrogen and Lessons from Outside Industry
Sep 2023
Publication
The recognition of hydrogen as a technically viable combustion fuel and as an alternative to more carbon intensive technologies for all forms of industrial applications has resulted in significant global interest leading to both public and private investment. As with most shifts in technology public acceptance and its safe production and handling will be key to its growth as a widespread energy vector. Specific properties of hydrogen that may prompt concern from the public and that need to be considered in terms of its use and safe handling include the following:<br/>• Hydrogen in its natural state is a colourless odourless and tasteless gas that is combustible with very low ignition energy burns nearly invisibly and is explosive at a very wide range of concentrations with an oxidate.<br/>• Hydrogen as any other gas except oxygen is an asphyxiant in a confined space.<br/>• Hydrogen is an extremely small molecule and interacts with many materials which over time can alter the physical properties and can lead to embrittlement and failure. Additionally due to the small molecular size its permeation and diffusion characteristics make it more difficult to contain compared to other gases.<br/>As hydrogen production use and storage increases these properties will come under greater scrutiny and may raise questions surrounding the cost/benefit of the technology. Understanding how the public sees this technology in relation to their safety and daily lives is important in hydrogen’s adoption as a low carbon alternative. A review of deployable experience relevant to the handling of hydrogen in other industries will help us to understand the technology and experience necessary for ensuring the success of the scaling up of a hydrogen economy. The social considerations of the impacts should also be examined to consider acceptance of the technology as it moves into the mainstream.
Numerical Simulation of Liquid Hydrogen Evaporation in the Pressurized Tank During Venting
Sep 2023
Publication
CFD modelling of liquified hydrogen boiling and evaporation during the pressurised tank venting is presented. The model is based on the volume-of-fluid method for tracking liquid and gas phases and Lee’s model for phase change. The simulation results are compared against the liquid hydrogen evaporation experiment performed by Tani et al. (2021) in a large-scale pressurised storage tank using experimental pressure dynamics and temperatures measured in gas and liquid phases. The study focuses on tank pressure decrease and recovery phenomena during the first 15 s of the venting process. The model sensitivity have been studied applying different Lee’s model evaporisation-condensation coefficients. The CFD model provided reasonable agreement with the observed pressure and gas phase temperature dynamics during the liquid hydrogen storage depressurisation using Lee’s model coefficient =0.05 s-1. Experimentalists’ hypothesis about particularly intensive boiling in the proximity of thermocouples was supported by close agreement between simulated and experimental saturation temperatures obtained from pressure dynamics.
Visualisation and Quantification of Wind-induced Variability in Hydrogen Clouds Following Releases of Liquid Hydrogen
Sep 2023
Publication
Well characterized experimental data for consequence model validation is important in progressing the use of liquid hydrogen as an energy carrier. In 2019 the Health and Safety Executive (HSE) undertook a series of liquid hydrogen dispersion and combustion experiments as a part of the Pre-normative Research for Safe Use of Liquid Hydrogen (PRESLHY) project. In partnership between the National Renewable Energy Laboratory (NREL) and HSE time and spatially varying hydrogen concentration measurements were made in 25 dispersion experiments and 23 congested ignition experiments associated with PRESLHY WP3 and WP5 respectively. These measurements were undertaken using the hydrogen wide area monitoring system developed by NREL. During the 23 congested ignition experiments high variability was observed in the measured explosion severity during experiments with similar initial conditions. This led to the conclusion that wind including localized gusts had a large influence on the dispersion of the hydrogen and therefore the quantity of hydrogen that was present in the congested region of the explosions. Using the hydrogen concentration measurements taken immediately prior to ignition the hydrogen clouds were visualized in an attempt to rationalize the variability in overpressure between the tests. Gaussian process regression was applied to quantify the variability of the measured hydrogen concentrations. This analysis could also be used to guide modifications in experimental designs for future research on hydrogen combustion behavior.
Lessons Learned from Large Scale Hydrogen Production Project
Sep 2023
Publication
In August 2022 Shell started construction of Holland Hydrogen I (HH I) a 200 MW electrolyser plant in the port of Rotterdam’s industrial zone on Maasvlakte II in the Netherlands. HH I will produce up to 60000 kg of renewable hydrogen per day. The development and demonstration of a safe layout and plant design had been challenging due to ambitious HH I project premises many technical novelties common uncertainties in hydrogen leak effect prediction a lack of large-scale water electrolyzer operating history and limited standardization in this industry sector. This paper provides an industry perspective of the major challenges in commercial electrolyzer plant HSSE risk assessment and risk mitigation work processes required to develop and demonstrate a safe design and it describes lessons learned in this area during the HH I project. Furthermore the paper lists major common gaps in relevant knowledge engineering tools standards and OEM deliverables that need closure to enable future commercial electrolyzer plant projects to develop an economically viable and plant design and layout more efficiently and cost-effectively.
The Latest Voyage of Discovery - Quantifying the Consequences of LH2 Releases for the Marine Industry
Sep 2023
Publication
Following a desktop study undertaken in 2021 to identify hazard scenarios associated with the use of liquid and compressed hydrogen on commercial shipping Shell has started a programme of large-scale experiments on the consequences of a release of liquid hydrogen. This work will compliment on-going research Shell has sponsored within several joint industry projects but will also address immediate concerns that the maritime industry has for the transportation of liquid hydrogen (LH2). This paper will describe the first phase of experiments involving the release of LH2 onto various substrates as well as dispersion across an instrumented test pad. These results will be used to address the following uncertainties in risk assessments within the hydrogen economy such as (1) Quantify the impact of low wind speed and high humidity on the buoyancy of both a passive and momentum jet dispersion cloud (2) Gather additional data on liquid hydrogen jet fires (3) Understand the likelihood for the formation of a sustained pool of hydrogen (4) Characterise materials especially passive fire protective coatings that are exposed to LH2. Not only will these experiments generate validation data to provide confidence in the Shell consequence tool FRED but they will also be used by Shell to support updates and new regulations developed by the International Maritime Organisation as it seeks to reduce CO2 intensity in the maritime industry.
IEA TCP Task 43 - Subtask Safety Distances: State of the Art
Sep 2023
Publication
The large deployment of hydrogen technologies for new applications such as heat power mobility and other emerging industrial utilizations is essential to meet targets for CO2 reduction. This will lead to an increase in the number of hydrogen installations nearby local populations that will handle hydrogen technologies. Local regulations differ and provide different safety and/or separation distances in different geographies. The purpose of this work is to give an insight on different methodologies and recommendations developed for hydrogen (mainly) risk management and consequences assessment of accidental scenarios. The first objective is to review available methodologies and to identify the divergent points on the methodology. For this purpose a survey has been launched to obtain the needed inputs from the subtask participants. The current work presents the outcomes of this survey highlighting the gaps and suggesting the prioritization of the actions to take to bridge these gaps.
Explosion Mitigation Techniques in Tunnels and their Applicability to Scenarios of Hydrogen Tank Rupture in a Fire
Sep 2023
Publication
This paper presents a comprehensive review of existing explosion mitigation techniques for tunnels and evaluates their applicability in scenarios of hydrogen tank rupture in a fire. The study provides an overview of the current state of the art in tunnel explosion mitigation and discusses the challenges associated with hydrogen explosions in the context of fire incidents. The review shows that there are several approaches available to decrease the effects of explosions including wrapping the tunnel with a flexible and compressible barrier and introducing energy-absorbing flexible honeycomb elements. However these methods are limited to the mitigation of the action and do not consider either the mitigation of the structural response or the effects on the occupants. The study highlights how the structural response is affected by the duration of the action and the natural period of the structural elements and how an accurate design of the element stiffness can be used in order to mitigate the structural vulnerability to the explosion. The review also presents various passive and active mitigation techniques aimed at mitigating the explosion effects on the occupants. Such techniques include tunnel branching ventilation openings evacuation lanes right-angled bends drop-down perforated plates or high-performance fibre-reinforced cementitious composite (HPFRCC) panels for blast shielding. While some of these techniques can be introduced during the tunnel's construction phase others require changes to the already working tunnels. To simulate the effect of blast wave propagation and evaluate the effectiveness of these mitigation techniques a CFD-FEM study is proposed for future analysis. The study also highlights the importance of considering these mitigation techniques to ensure the safety of the public and first responders. Finally the study identifies the need for more research to understand blast wave mitigation by existing structural elements in the application for potential accidents associated with hydrogen tank rupture in a tunnel.
No more items...