United Kingdom

The HyDeploy project has undertaken a programme of work to assess the effect of hydrogen addition on the safety and performance of gas appliances and installations. A representative set of eight appliances have been assessed in laboratory experiments with a range of test gases that explored high and low Wobbe Index and hydrogen concentrations up to 28.4 % mol/mol. These tests have demonstrated that the addition of hydrogen does not affect the key hazard areas of CO production light back flame out or the operation of flame failure devices. It was identified that for some designs of gas fire appliances the operation of the oxygen depletion sensors may be affected by the addition of hydrogen. Testing of the gas fires that are present at Keele University that use oxygen depletion sensors have been shown to operate satisfactorily.<br/>A comprehensive onsite survey programme at Keele University has assessed 95% of the installations (126 of 133) that will receive the hydrogen blended gas during the HyDeploy trial. Where access to properties was not possible then the information obtained revealed that the appliances were annually checked either through British Gas service contracts or as a result of being rental properties. The onsite testing programme assessed installations for gas tightness and appliance combustion safety and operation with normal line gas G20 reference gas and two hydrogen blended gases. The checks identified a small number instances were remedial work was required to correct poor condition or operation. Only one case was found to be immediately dangerous which was capped off until repair work was undertaken. CO and smoke alarms were fitted in approximately half of properties and alarms were provided as required to the occupants. Gas tightness tests identified leaks in three installations. Where installations are gas tight then analysis has shown that no additional leaks would occur with hydrogen blended gas. There were no issues identified with the combustion performance of those appliances that were operating correctly and results were in line with those obtained in the laboratory testing programme.<br/>The findings of the Appliance and Installation testing program have been used to define the input values into the HyDeploy quantified risk assessment (QRA) where Keele University specific operation is different to GB as a whole or where the findings show the addition of hydrogen will change the risk profile.<br/>Click on supplements to see the other documents from this report

In its new report Making the Hydrogen Economy Possible: Accelerating clean hydrogen in an electrified economy the ETC outlines the role of clean hydrogen in achieving a highly electrified net-zero economy. The report sets out how a combination of private-sector collaboration and policy support can drive the initial ramp up of clean hydrogen production and use to reach 50 million tonnes by 2030.<br/>Clean hydrogen will play a complementary role to decarbonise sectors where direct electrification is likely to be technologically very challenging or prohibitively expensive such as in steel production and long-distance shipping. The report highlights how critical rapid ramp-up of production and use in the 2020s is to unlock cost reductions and to make mid-century growth targets achievable.<br/>This report is part of the ETC’s wider Making Mission Possible Series – a series of reports outlining how to scale up clean energy provision within the next 30 years to meet the needs of a net-zero greenhouse gas emissions (GHG) economy by mid-century. The reports in the series analyse and set out specific actions required in the next decade to put this net-zero by 2050 target within reach.

In the framework of the EU-funded project HyTunnel-CS an inter-comparison among partners CFD simulations  has  been  carried  out.  The simulations  are  based  on  experiments  conducted   within  the project by Pro-Science and involve hydrogen release inside a safety vessel testing different ventilation configurations. The different ventilation configurations that were tested are co-flow counter-flow and cross-flow.  In the  current  study  co-flow  and  counter-flow  tests   along  with  the  no  ventilation  test (m'  = S g/s  d = 4 mm ) are simulated with the aim to validate available and well-known CFD codes against  such  applications  and  to  provide   recommendations  on  modeling  strategies. Special  focus  is given on modeling the velocity field produced by the fan during the experiments. The computational results are compared with the experimental results and a discussion follows regarding the efficiency of each ventilation configuration.

We demonstrate a new approach for producing highly dispersed supported metal phosphide powders with small particle size improved stability and increased electrocatalytic activity towards some useful reactions. The approach involves a one-step conversion of metal supported on high surface area carbon to the metal phosphide utilising a very simple and scalable synthetic process. We use this approach to produce PdP₂ and Pd₅P₂ particles dispersed on carbon with a particle size of 4.5–5.5 nm by converting a commercially available Pd/C powder. The metal phosphide catalysts were tested for the oxygen reduction hydrogen oxidation and evolution and formic acid oxidation reactions. Compared to the unconverted Pd/C material we find that alloying the P at different levels shifts oxide formation on the Pd to higher potentials leading to greater stability during cycling studies (20% more ECSA retained 5k cycles) and in thermal treatment under air. Hydrogen absorption within the PdP₂ and Pd₅P₂ particles is enhanced. The phosphides compare favourably to the most active catalysts reported to date for formic acid oxidation especially PdP₂ and there is a significant decrease in poisoning of the surface compared to Pd alone. The mechanistic changes in the reactions studied are rationalised in terms of increased water activation on the surface phosphorus atoms of the catalyst. One of the catalysts PdP₂/C is tested in a fuel cell as anode and cathode catalyst and shows good performance.

The aim of this project was to review the current purge standards for UK domestic installations in particular IGEM/UP/1B and carry out experiments to assess the validity of those standards for use in hydrogen in order to understand and recommend safe purge practices for hydrogen in a domestic environment.

This report provides the results and conclusions relating to the relative safety of purging domestic installations to hydrogen compared to Natural Gas and the implications of releasing any purged gas

into an enclosed volume representing a small room.

The two high-level findings from this work are:

• changeover to hydrogen will result in an increased risk of flammability inside the installation pipework
• changeover to hydrogen will result in a reduced risk of a build-up of flammable gas in any room where purging occurs.

This work recognises a number of important differences between hydrogen and methane. Hydrogen is more flammable than methane in air particularly at high concentrations. Hydrogen can maintain a flame at 4% but does not support general three dimensional deflagration until about 8.5%. Above about 18% given increased obstruction within the combustion zone or passage of the flame along a pipe the deflagration can transition to detonation. The flame speed suddenly increases to ~2000m/s. It is very important to avoid this situation although the inventory in a domestic pipe is low. This risk of detonation can occur at concentrations up to 59% and the risk of deflagration remains to 75 %.Methane behaves very differently to this with a range of deflagration of about 4.8 to 16% and a detonation range only marginally narrower. Initiating detonation is however much more difficult with methane.

The risks with hydrogen are associated with a wide range of flammability with methane the risks are smaller and mainly in lower concentrations of gas in air. Because of this it is particularly important to ensure hydrogen pipes are appropriately purged.

UK homes are primarily heated by fossil fuels and contribute 13% of UK’s carbon footprint (equivalent to all the UK’s 38.4m cars). The report says this is incompatible with UK climate legislation targeting net-zero economy by 2050. New polling finds that consumers are open to cleaner greener ways to heat their homes into the future but that they are “still in the dark about smarter greener heating solutions and lack access to independent advice to help them make better decisions for their homes pockets and the planet”.<br/><br/>The report – Uncomfortable Home Truths: why Britain urgently needs a low carbon heat strategy – says a bold new national roadmap is needed by 2020 which puts consumers and households at the heart of a revolution in green heat innovation. It recommends the creation of an Olympic-style delivery body to catalyse and coordinate regional innovation and local leadership tailored to different parts of the UK and the nation’s diverse housing stock.<br/><br/>This report is the third in the Future Gas Series which has explored the opportunities and challenges associated with using low carbon gas in the energy system and is backed by cross-party parliamentary co-Chairs

Hydrogen is a convenient energy storage medium; it can be produced from fossil fuels and biomass via chemical conversion processes or from intermittent renewable sources like wind and solar via electrolysis. It is the fuel of choice for the clean fuel-cell vehicles of the future. If the general public are to use hydrogen as a vehicle fuel customers must be able to handle hydrogen with the same degree of confidence and with comparable risk as conventional liquid and gaseous fuels. For the safe design of retail facilities through the development of appropriate codes and standards it is essential to understand all the hazards that could arise following an accidental release of hydrogen. If it is to be stored and used as a high-pressure gas the hazards associated with jet releases from accidental leaks must be considered. This paper describes work by Shell and the Health and Safety Laboratory to characterise the hazards from jet releases of hydrogen. Jet release experiments have been carried out using small leaks (circular holes ranging from 1 mm to 12 mm diameter) at system pressures up to 150 barg. Concentration measurements were made in the unignited free jets to determine the extent of the flammable cloud generated. Ignited jets were observed both in the visible and infrared to determine the flame size and shape. The experimental results for the extent of the flammable cloud and jet flame length were found to be in good agreement with model predictions.

The characterization of liquid hydrogen (LH2) releases has been identified as an international research priority to facilitate the safe use of hydrogen as an energy carrier. Empirical field measurements such as those afforded by Hydrogen Wide Area Monitoring can elucidate the behavior of LH2 releases which can then be used to support and validate dispersion models. Hydrogen Wide Area Monitoring can be defined as the quantitative three-dimensional spatial and temporal profiling of planned or unintentional hydrogen releases. The NREL Sensor Laboratory developed a Hydrogen Wide Area Monitor (HyWAM) based upon a distributed array of hydrogen sensors. The NREL Sensor Laboratory and the Health and Safety Executive (HSE) formally committed to collaborate on profiling GH2 and LH2 releases which allowed for the integration of the NREL HyWAM into the HSE LH2 release behavior investigation supported by the FCH JU Prenormative Research for the Safe Use of Liquid Hydrogen (PRESLHY) program. A HyWAM system was deployed consisting of 32 hydrogen measurement points and co-located temperature sensors distributed downstream of the LH2 release apparatus developed by HSE. In addition the HyWAM deployment was supported by proximal wind and weather monitors. In a separate presentation at this conference “HSE Experimental Summary for the Characterisation Dispersion and Electrostatic Hazards of LH2 for the PRESLHY Project” HSE researchers summarize the experimental apparatus and protocols utilized in the HSE LH2 releases that were performed under the auspices of PRESLHY. As a supplement to the HSE presentation this presentation will focus on the spatial and temporal behavior LH2 releases as measured by the NREL HyWAM. Correlations to ambient conditions such as wind speed and direction plume temperature and hydrogen concentrations will be discussed in addition to the design and performance of the NREL HyWAM and its potential for improving hydrogen facility safety.

A new report to the Secretary of State for Business Energy and Industrial Strategy from the Parliamentary Advisory Group on Carbon Capture and Storage (CCS) advises that that the UK  should kickstart CCS in order to save consumers billions a year from the cost of meeting climate change targets.

The Institution of Gas Engineers & Managers (IGEM) is the UK’s Professional Engineering Institution supporting individuals and businesses working in the global gas industry. IGEM was founded in 1863 with the purpose of advancing the science and relevant knowledge of gas engineering for the benefit of the public.



As a not-for-profit independent organisation IGEM acts as a trusted source of technical information guidance and services for the gas sector. In today’s net zero context IGEM is focused on engineering a sustainable gas future – we do this by:

• Helping our members achieve and uphold the highest standards of professional competence to ensure the safety of the public
• Supporting our members in achieving their career goals by providing high quality products services and personal and professional development opportunities 
• Acting as the voice of the gas industry when working with stakeholders to develop and improve gas policy. 

This document outlines the current UK gas policy landscape our stance and what contribution we are making as an organisation.

Electrical power generation is changing dramatically across the world because of the need to reduce greenhouse gas emissions and to introduce mixed energy sources. The power network faces great challenges in transmission and distribution to meet demand with unpredictable daily and seasonal variations. Electrical Energy Storage (EES) is recognized as underpinning technologies to have great potential in meeting these challenges whereby energy is stored in a certain state according to the technology used and is converted to electrical energy when needed. However the wide variety of options and complex characteristic matrices make it difficult to appraise a specific EES technology for a particular application. This paper intends to mitigate this problem by providing a comprehensive and clear picture of the state-of-the-art technologies available and where they would be suited for integration into a power generation and distribution system. The paper starts with an overview of the operation principles technical and economic performance features and the current research and development of important EES technologies sorted into six main categories based on the types of energy stored. Following this a comprehensive comparison and an application potential analysis of the reviewed technologies are presented.

Water electrolysis supplied by renewable energy is the foremost technology for producing ‘‘green” hydrogen for fuel cell vehicles. In addition the ability to rapidly follow an intermittent load makes electrolysis an ideal solution for grid-balancing caused by differences in supply and demand for energy generation and consumption. Membrane-electrode assemblies (MEAs) designed for polymer electrolyte membrane (PEM) water electrolysis based on a novel short-side chain (SSC) perfluorosulfonic acid (PFSA) membrane Aquivion with various cathode and anode noble metal loadings were investigated in terms of both performance and durability. Utilizing a nanosized Ir_0.7Ru_0.3O solid solution anode catalyst and a supported Pt/C cathode catalyst in combination with the Aquivion membrane gave excellent electrolysis performances exceeding 3.2 A cm^-2 at 1.8 V terminal cell voltage ( 80% efficiency) at 90 ºC in the presence of a total catalyst loading of 1.6 mg cm⁻². A very small loss of efficiency corresponding to 30 mV voltage increase was recorded at 3 A cm 2 using a total noble metal catalyst loading of less than 0.5 mg cm⁻² (compared to the industry standard of 2 mg cm⁻²). Steady-state durability tests carried out for 1000 h at 1 A cm ^-2 showed excellent stability for the MEA with total noble metal catalyst loading of 1.6 mg cm⁻² (cell voltage increase  5 lV/h). Moderate degradation rate (cell voltage increase 15 lV/h) was recorded for the low loading 0.5 mg cm^-2 MEA. Similar stability characteristics were observed in durability tests at 3 A cm⁻². These high performance and stability characteristics were attributed to the enhanced proton conductivity and good stability of the novel membrane the optimized structural properties of the the enhanced proton conductivity and good stability of the novel membrane the optimized structural properties of the the enhanced proton conductivity and good stability of the novel membrane the optimized structural properties of the Ir and Ru oxide solid solution and the enrichment of Ir species on the surface for the anodic catalyst.

This research considers the potential role of hydrogen in meeting the UK’s carbon budgets. It was written by consultancy E4tech.<br/>The CCC develops scenarios for the UK’s future energy system to assess routes to decarbonisation and to advise UK Government on policy options. Uncertainty to 2050 is considerable and so different scenarios are needed to assess different trajectories targets and technology combinations. Some of these scenarios assess specific technologies or fuels which have the potential to make a significant contribution to future decarbonisation.<br/>Hydrogen is one such fuel. It has been included in limited quantities in some CCC scenarios but not extensively examined in part due to perceived or anticipated higher costs than some other options. But as hydrogen technology is developed and deployed the cost projections and other performance indicators have become more favourable.

Heating and hot water for UK buildings make up 40% of our energy consumption and 20% of our greenhouse gas emissions. It will be necessary to largely eliminate these emissions by around 2050 to meet the targets in the Climate Change Act and to maintain the UK contribution to international action under the Paris Agreement.<br/>Progress to date has stalled. The Government needs a credible new strategy and a much stronger policy framework for buildings decarbonisation over the next three decades. Many of the changes that will reduce emissions will also contribute toward modern affordable comfortable homes and workplaces and can be delivered alongside a major expansion in the number of homes. This report considers that challenge and sets out possible steps to meet it.

Energy used for heat accounts (in terms of final consumption) for approximately 45% of our total energy needs and is critical for families to heat their homes on winter days. Decarbonising heat while still meeting peak winter heating demands is recognised as a big perhaps the biggest challenge for the industry. The way heat has been delivered in the UK has not fundamentally changed for decades and huge investments have been made in gas infrastructure assets ranging from import terminals to networks through to the appliances in our homes. Changing how heat is delivered whichever way is chosen will be a major economic and practical challenge affecting families and businesses everywhere. Any plan to decarbonise will need to address power and transport alongside heat. Our report has also looked at potential decarbonisation of power and transport as part of a whole energy system approach.

In this report we explore ways that the heat sector can be decarbonised by looking at four possible future scenarios set in 2050. These stylised scenarios present illustrative snapshots of alternative energy solutions. The scenarios do not present a detailed roadmap – indeed the future may include some elements from each. We have analysed the advantages disadvantages and costs of each scenario. All our scenarios meet the 2050 Carbon emissions targets. In this report we have concentrated on reductions to CO₂ emissions and we have not considered other greenhouse gases.

This document provides guidance on the commercial and strategic elements of a heat network project to support completion of a project business case.

The guidance is intended for local authorities and heat network developers to support their investigations and enable progression from feasibility stage through to business case delivery. The guidance has been drafted with reference to policy legislation and regulation in England and Wales; however much of the guidance is likely also to be relevant to projects in Scotland and Northern Ireland.

The guidance specifically supports the HMT Green Book Five Cases Business Model (the Five Cases Model) and the derived DBEIS Business Case Template (DBEIS BCT) that follows this structure but will also be applicable in other instances. The Five Cases Model (and similarly the DBEIS BCT) considers the viability of the project from five perspectives:

• Strategic
• Economic
• Commercial
• Financial
• Management

Although all five elements are relevant this guide particularly focuses on the Strategic and Commercial cases.

Related Document Heat Networks 2020

In order for fuel cell vehicles to develop a widespread role in society it is essential that hydrogen refuelling stations become established. For this to happen there is a need to demonstrate the safety of the refuelling stations. The work described in this paper was carried out to provide experimental information on hydrogen outflow dispersion and explosion behaviour. In the first phase homogeneous hydrogen-air-mixtures of a known concentration were introduced into an explosion chamber and the resulting flame speed and overpressures were measured. Hydrogen concentration was the dominant factor influencing the flame speed and overpressure. Secondly high-pressure hydrogen releases were initiated in a storage room to study the accumulation of hydrogen. For a steady release with a constant driving pressure the hydrogen concentration varied as the inlet airflow changed depending on the ventilation area of the room the external wind conditions and also the buoyancy induced flows generated by the accumulating hydrogen. Having obtained this basic data the realistic dispersion and explosion experiments were executed at full-scale in the hydrogen station model. High-pressure hydrogen was released from 0.8-8.0mm nozzle at the dispenser position and inside the storage room in the full-scale model of the refuelling station. Also the hydrogen releases were ignited to study the overpressures that can be generated by such releases. The results showed that overpressures that were generated following releases at the dispenser location had a clear correlation with the time of ignition distance from ignition point.

This paper describes research work that has been performed at LSBU using both a laminar burning velocity rig and a small scale cylindrical explosion vessel to explore the use of very fine water fog nitrogen dilution and sodium hydroxide additives in the mitigation of hydrogen deflagrations. The results of the work suggest that using a combination of the three measures together produces the optimal mitigation performance and can be extremely effective in: inhibiting the burning velocity reducing the rate of explosion overpressure rise and narrowing the flammability limits of hydrogen-oxygen-nitrogen mixtures.

Hydrogen technologies are expected to play a key role in implementing the transition from a fossil fuel- based to a more sustainable lower-carbon energy system. To facilitate their widespread deployment the safe operation and hydrogen systems needs to be ensured together with the evaluation of the associated risk.<br/>HIAD has been designed to be a collaborative and communicative web-based information platform holding high quality information of accidents and incidents related to hydrogen technologies. The main goal of HIAD was to become not only a standard industrial accident database but also an open communication platform suitable for safety lessons learned and risk communication as well as a potential data source for risk assessment; it has been set up to improve the understanding of hydrogen unintended events to identify measures and strategies to avoid incidents/accidents and to reduce the consequence if an accident occurs.<br/>In order to achieve that goal the data collection is characterized by a significant degree of detail and information about recorded events (e.g. causes physical consequences lesson learned). Data are related not only to real incident and accidents but also to hazardous situations.<br/>The concept of a hydrogen accident database was generated in the frame of the project HySafe an EC co-funded NoE of the 6th Frame Work Programme. HIAD was built by EC-JRC and populated by many HySafe partners. After the end of the project the database has been maintained and populated by JRC with publicly available events. The original idea was to provide a tool also for quantitative risk assessment able to conduct simple analyses of the events; unfortunately that goal could not be reached because of a lack of required statistics: it was not possible to establish a link with potential event providers coming from private sector not willing to share information considered confidential. Starting from June 2016 JRC has been developing a new version of the database (i.e. HIAD 2.0); the structure of the database and the web-interface have been redefined and simplified resulting in a streamlined user interface compared to the previous version of HIAD. The new version is mainly focused to facilitate the sharing of lessons learned and other relevant information related to hydrogen technology; the database will be public and the events will be anonymized. The database will contribute to improve the safety awareness fostering the users to benefit from the experiences of others as well as to share information from their own experiences.

There has recently been a concerted effort to commence a transition to fuel cell vehicles (FCVs) in Europe. A coalition of companies released an influential McKinsey-coordinated report in 2010 which concluded that FCVs are ready for commercial deployment. Public–private H2Mobility programmes have subsequently been established across Europe to develop business cases for the introduction of FCVs. In this paper we examine the conclusions of these studies from an energy systems perspective using the UK as a case study. Other UK energy system studies have identified only a minor role for FCVs after 2030 but we reconcile these views by showing that the differences are primarily driven by different data assumptions rather than methodological differences. Some energy system models do not start a transition to FCVs until around 2040 as they do not account for the time normally taken for the diffusion of new powertrains. We show that applying dynamic growth constraints to the UK MARKAL energy system model more realistically represents insights from innovation theory. We conclude that the optimum deployment of FCVs from an energy systems perspective is broadly in line with the roadmap developed by UK H2Mobility and that a transition needs to commence soon if FCVs are to become widespread by 2050.

A core theme of the UK Government's new Industrial Strategy is exploiting opportunities for domestic supply chain development. This extends to a special ‘Automotive Sector Deal’ that focuses on the shift to low emissions vehicles (LEVs). Here attention is on electric vehicle and battery production and innovation. In this paper we argue that a more straightforward gain in terms of framing policy around potential economic benefits may be made through supply chain activity to support refuelling of battery/hydrogen vehicles. We set this in the context of LEV refuelling supply chains potentially replicating the strength of domestic upstream linkages observed in the UK electricity and/or gas industries. We use input-output multiplier analysis to deconstruct and assess the structure of these supply chains relative to that of more import-intensive petrol and diesel supply. A crucial multiplier result is that for every £1million of spending on electricity (or gas) 8 full-time equivalent jobs are supported throughout the UK. This compares to less than 3 in the case of petrol/diesel supply. Moreover the importance of service industries becomes apparent with 67% of indirect and induced supply chain employment to support electricity generation being located in services industries. The comparable figure for GDP is 42%.

Spontaneous ignition of compressed hydrogen release through a length of tube with different internal geometries is numerically investigated using our previously developed model. Four types of internal geometries are considered: local contraction local enlargement abrupt contraction and abrupt enlargement. The presence of internal geometries was found to significantly increase the propensity to spontaneous ignition. Shock reflections from the surfaces of the internal geometries and the subsequent shock interactions further increase the temperature of the combustible mixture at the contact region. The presence of the internal geometry stimulates turbulence enhanced mixing between the shock-heated air and the escaping hydrogen resulting in the formation of more flammable mixture. It was also found that forward-facing vertical planes are more likely to cause spontaneous ignition by producing the highest heating to the flammable mixture than backward-facing vertical planes.

Recently ammonia is being considered for fuelling gas turbines as a new sustainable source. It can undergo thermal cracking producing nitrogen hydrogen and unburned ammonia thus enabling the use of these chemicals most efficiently for combustion purposes. Ammonia being carbon-free may allow the transition towards a hydrogen economy. However one of the main constraints of this fuelling technique is that although the combustion of ammonia produces no CO2 there is a large NOx proportion of emissions using this fuel. In this work cracked ammonia obtained from a modified combustion rig designed at Cardiff University was used to simulate a swirl burner under preheating conditions via heat exchangers. The primary objective of this system is to find new ways for the reduction of NOx emissions by injecting various amounts of ammonia/hydrogen at different mixtures downstream of the primary flame zone. The amount of injected ammonia/hydrogen mixture (X) taken from the thermal cracking system was ranged from 0%-4% (vol %) of the total available fuel in the system while the remaining gas (1.00-X) was then employed as primary fuel into the burner. CHEMKIN- PRO calculations were conducted by employing a novel chemical reaction code developed at Cardiff University to achieve the goal of this paper. The predictions were performed under low pressure and rich conditions with an equivalence ratio ϕ =1.2 in a swirl burner previously characterised at output powers of ~10 kW. Ammonia and hydrogen blends were evaluated from 50% NH3 (vol %) with the remaining gas as hydrogen continuing in steps of 10% (vol %) NH3 increments. Results showed that the minimum unburned ammonia and higher flame temperature were achieved at 60%-40% NH3-H2 when compared to other blends but with high NO emissions. These NO levels were reduced by injecting a small amount of NH3/H2 mixture (X=4 %) downstream the primary zone in a generated circulations promoted by the new design of the burner which affecting the residence time hence reducing the NO emission in the exhaust gas.

The development of a ‘Hydrogen Economy’ will see hydrogen fuel cells used in transportation and the generation of power for buildings as part of a decentralised grid with low power units used in domestic and commercial environmental situations. Low power fuel cells will be housed in small protective enclosures which must be ventilated to prevent a build-up of hydrogen gas produced during normal fuel cell operation or a supply pipework leak. Hydrogen’s flammable range (4-75%) is a significant safety concern. With poor enclosure ventilation a low-level leak (below 10 lpm) could quickly create a flammable mixture with potential for an explosion. Mechanical ventilation is effective at managing enclosure hydrogen concentrations but drains fuel cell power and is vulnerable to failure. In many applications (e.g. low power and remote installation) this is undesirable and reliable passive ventilation systems are preferred. Passive ventilation depends upon buoyancy driven flow with the size and shape of ventilation openings critical for producing predictable flows and maintaining low buoyant gas concentrations. Environmentally installed units use louvre vents to protect the fuel cell but the performance of these vents compared to plain vertical vents is not clear. Comparison small enclosure tests of ‘same opening area’ louvre and plain vents with leak rates from 1 to 10 lpm were conducted. A displacement ventilation arrangement was installed on the test enclosure with upper and lower opposing openings. Helium gas was released from a 4mm nozzle at the base of the enclosure to simulate a hydrogen leak. The tests determined that louvre vents increased average enclosure hydrogen concentrations by approximately 10% across the leak range tested but regulated the flow. The test data was used in a SolidWorks CFD simulation model validation exercise. The model provided a good qualitative representation of the flow behaviour but under predicted average concentrations.

An overview of the HyDeploy project at Keele University where hydrogen is being blended with natural gas to demonstrate the feasibility of using hydrogen to heat our homes.

A key challenge for future clean power or hydrogen projects via gasification is the need to reduce the overall cost while achieving significant levels of CO2 capture. The current state of the art technology for capturing CO2 from sour syngas uses a physical solvent absorption process (acid gas removal–AGR) such as Selexol™ or Rectisol® to selectively separate H2S and CO2 from the H2. These two processes are expensive and require significant utility consumption during operation which only escalates with increasing levels of CO2 capture. Importantly Air Products has developed an alternative option that can achieve a higher level of CO2 capture than the conventional technologies at significantly lower capital and operating costs. Overall the system is expected to reduce the cost of CO2 capture by over 25%.<br/>Air Products developed this novel technology by leveraging years of experience in the design and operation of H2 pressure swing adsorption (PSA) systems in its numerous steam methane reformers. Commercial PSAs typically operate on clean syngas and thus need an upstream AGR unit to operate in a gasification process. Air Products recognized that a H2 PSA technology adapted to handle sour feedgas (Sour PSA) would enable a new and enhanced improvement to a gasification system. The complete Air Products CO2 Capture technology (CCT) for sour syngas consists of a Sour PSA unit followed by a low-BTU sour oxycombustion unit and finally a CO2 purification / compression system.

This paper reports experimental results from a series of experiments in which gaseous hydrogen was released into a 31 m3 enclosure and the hydrogen concentrations at a number of points within the enclosure were monitored to assess whether hydrogen accumulation occurred and whether a homogeneous or stratified mixture was formed. The enclosure was located in the open air and therefore subject to realistic and therefore variable wind conditions. The hydrogen release rate and the passive vent arrangements were varied. The experiments were carried out as part of the EU Hyindoor Project.

The characterization of liquid hydrogen (LH2) releases has been identified as an international research priority to expand the safe use of hydrogen as an energy carrier. The elucidation of LH2 release behavior will require the development of dispersion and other models guided and validated by empirical field measurements such as those afforded by Hydrogen Wide Area Monitoring (HyWAM). HyWAM can be defined as the quantitative spatial and temporal three-dimensional monitoring of planned or unintentional hydrogen releases. With support provided through the FCH JU Prenormative Research for the Safe Use of Liquid Hydrogen (PRESLHY) program HSE performed a series of LH2 releases to characterize the dispersion and pooling behavior of cold hydrogen releases. The NREL Sensor Laboratory developed a HyWAM system based upon a distributed array of point sensors that is amenable for profiling cold hydrogen plumes. The NREL Sensor Laboratory and HSE formally committed to collaborate on profiling the LH2 releases. This collaboration included the integration of the NREL HyWAM into the HSE LH2 release hardware. This was achieved through a deployment plan jointly developed by the NREL and HSE personnel. Under this plan the NREL Sensor Laboratory provided multiple HyWAM modules that accommodated 32 sampling points for near-field hydrogen profiling during the HSE PRESLHY LH2 releases. The NREL HyWAM would be utilized throughout the LH2 release study performed under PRESLHY by HSE including Work Package 3 (WP3—Release and Mixing--Rainout) and subsequent work packages (WP4—Ignition and WP5—Combustion). Under the auspices of the PRESLHY WP6 (Implementation) data and findings from the HSE LH2 Releases are to be made available to stakeholders in the hydrogen community. Comprehensive data analysis and dissemination is ongoing but the integration of the NREL HyWAM into the HSE LH2 Release Apparatus and its performance as well as some key outcomes of the LH2 releases in WP3 are presented.

A project overview of HyDeploy project led by Cadent Gas and supported by Northern Gas Networks Progressive Energy Ltd Keele University HSE – Science Division and ITM Power.

First Phase:

HyDeploy at Keele is the first stage of this three stage programme. In November 2019 the UK Health & Safety Executive gave permission to run a live test of blended hydrogen and natural gas on part of the private gas network at Keele University campus in Staffordshire. HyDeploy is the first project in the UK to inject hydrogen into a natural gas network.

Second and Third Phases;

Once the Keele stage has been completed HyDeploy will move to a larger demonstration on a public network in the North East. After that HyDeploy will have another large demonstration in the North West.  These are designed to test the blend across a range of networks and customers so that the evidence is representative of the UK as a whole. With HSE approval and success at Keele these phases will go ahead in the early 2020s.

The longer term goal:

Once the evidence has been submitted to Government policy makers we very much expect hydrogen to take its place alongside other forms of zero carbon energy in meeting the needs of the UK population.

In the event of a fire composite pressure vessels behave very differently from metallic ones: the material is degraded potentially leading to a burst without significant pressure increase. Hence such objects are when necessary protected from fire by using thermally-activated devices (TPRD) and standards require testing cylinder and TPRD together. The pre-normative research project FireComp aimed at understanding better the conditions which may lead to burst through testing and simulation and proposed an alternative way of assessing the fire performance of composite cylinders. This approach is currently used by Air Liquide for the safety of composite bundles carrying large amounts of hydrogen gas.

On October 16-17 2012 the International Association for Hydrogen Safety (HySafe) in cooperation with the Institute for Energy and Transport of the Joint Research Centre of the European Commission (JRC IET Petten) held a two-day workshop dedicated to Hydrogen Safety Research Priorities. The workshop was hosted by Federal Institute for Materials Research and Testing (BAM) in Berlin Germany. The main idea of the Workshop was to bring together stakeholders who can address the existing knowledge gaps in the area of the hydrogen safety including identification and prioritization of such gaps from the standpoint of scientific knowledge both experimental and theoretical including numerical. The experience highlighting these gaps which was obtained during both practical applications (industry) and risk assessment should serve as reference point for further analysis. The program included two sections: knowledge gaps as they are addressed by industry and knowledge gaps and state-of-the-art by research. In the current work the main results of the workshop are summarized and analysed.

The UK has an extensive natural gas pipeline network supplying 84% of homes. Previous studies of decarbonisation pathways using the UK MARKAL energy system model have concluded that the low ­pressure gas networks should be mostly abandoned by 2050. yet most of the iron pipes near buildings are currently being replaced early for safety reasons. Our study suggests that this programme will not lock-in the use of gas in the long-term. We examine potential future uses of the gas network in the UK energy system using an improved version of UK MARKAL that introduces a number of decarbonisation options for the gas network including bio-methane hydrogen injection to the natural gas and conversion of the network to deliver hydrogen.<br/>We conclude that hydrogen conversion is the only gas decarbonisa­tion option that might enable the gas networks to continue supplying energy to most buildings in the long-term from a cost-optimal perspective. There is an opportunity for the government to adopt a long­t erm strategy for the gas distribution networks that either curtails the iron mains replacement programme or alters it to prepare the network for hydrogen conversion; both options could substantially reduce the long-term cost of supplying heat to UK buildings.

If the ‘Hydrogen Economy’ is to progress more hydrogen fuelling stations are required. In the short term and in the absence of a hydrogen distribution network these fuelling stations will have to be supplied by liquid hydrogen (LH2) road tankers. Such a development will increase the number of tanker offloading operations significantly and these may need to be performed in close proximity to the general public. LH2 was first investigated experimentally as large-scale spills of LH2 at a rate of 60 litres per minute. Measurements were made on un-ignited releases which included the concentration of hydrogen in air thermal gradients in the concrete substrate liquid pool formation and temperatures within the pool. Computational modelling on the un-ignited spills was also performed. The experimental work on ignited releases of LH2 detailed in this paper is a continuation of the work performed by Royle and Willoughby. The experimental findings presented are split into three phenomena; jet-fires in high and low wind conditions ‘burn-back’ of ignited clouds and secondary explosions post ‘burn-back’. The aim of this work was to determine the hazards and severity of a realistic ignited spill of LH2 focussing on; flammability limits of an LH2 vapour cloud flame speeds through an LH2 vapour cloud and subsequent radiative heat levels after ignition. An attempt was made to estimate the magnitude of an explosion that occurred during one of the releases. The results of these experiments will inform the wider hydrogen community and contribute to the development of more robust modelling tools. The resulting data were used to propose safety distances for LH2 offloading facilities which will help to update and develop guidance for codes and standards.

The European Commission are funding an investigation of the feasibility of using existing natural gas infrastructures to transport and distribute hydrogen as a mixture of natural gas and hydrogen from the point of hydrogen production to the point of use. Since hydrogen has different chemical and physical properties to that of natural gas and these will affect the integrity and durability of the pipeline network and the ignition and combustion behaviour of released gas it is necessary to assess the change in risk to the public that would result. The subject of this paper is an experimental study of the effect of the hydrogen content of the natural gas-hydrogen mixture on the minimum energy required for ignition and the probability of achieving ignition given a particular level of energy discharge. It was possible to normalize the results for ignition energy such that given information on the minimum ignition energy and the equivalence ratio at which the minimum ignition energy occurs the lowest ignition energy for any other equivalence ratio can be predicted. The results also showed that the ignition process has a probabilistic element and that the probability of ignition is related to the equivalence ratio and the energy level of the source. It was observed that the probability of ignition increased with increasing energy of the source and that the rate of rise in probability was steepest for the equivalence ratios close to the equivalence ratio at which the minimum ignition energy occurs.

The present work is concerned with numerical simulations of large scale hydrogen detonations. Euler equations have been solved along with a single step reaction for the chemistry. Total variation diminishing (TVD) numerical schemes are used for shock capturing. The equations are solved in parallel in a decomposed domain. Predictions were firstly conducted with a small domain to ensure that the reaction scheme has been properly tuned to capture the correct detonation pressure and velocity. On this basis simulations were set up for the detonation tests carried out at the RUT tunnel facilities in Russia. This is one of the standard benchmark test cases selected for HYSAFE [1]. Comparison is made between the predictions and measurements. Reasonably good agreement has been obtained on pressure decay and the propagation speed of detonation. Further simulations were then conducted for a hypothetical hydrogen-air cloud in the open to assess the impulse as well as overpressure. The effects of cloud height width were investigated in the safety context.

Computational Fluid Dynamics solvers are developed for explosion modelling and hazards analysis in Hydrogen air mixtures. The work is presented in two parts. These include firstly a numerical approach to simulate flame acceleration and deflagration to detonation transition (DDT) in hydrogen–air mixture and the second part presents comparisons between two approaches to detonation modelling. The detonation models are coded and the predictions in identical scenarios are compared. The DDT model which is presented here solves fully compressible multidimensional transient reactive Navier–Stokes equations with a chemical reaction mechanism for different stages of flame propagation and acceleration from a laminar flame to a highly turbulent flame and subsequent transition from deflagration to detonation. The model has been used to simulate flame acceleration (FA) and DDT in a 2-D symmetric rectangular channel with 0.04 m height and 1 m length which is filled with obstacles. Comparison has been made between the predictions using a 21-step detailed chemistry as well as a single step reaction mechanism. The effect of initial temperature on the run-up distances to DDT has also been investigated. Comparative study has also been carried out for two detonation solvers. one detonation solver is developed based on the solution of the reactive Euler equations while the other solver has a simpler approach based on Chapman–Jouguet model and the programmed CJ burn method. Comparison has shown that the relatively simple CJ burn approach is unable to capture some very important features of detonation when there are obstacles present in the cloud.

HyDeploy is a pioneering hydrogen energy project designed to help reduce UK CO2 emissions and reach the Government’s net zero target for 2050.

As the first ever live demonstration of hydrogen in homes HyDeploy aims to prove that blending up to 20% volume of hydrogen with natural gas is a safe and greener alternative to the gas we use now.  It is  providing evidence on how customers don’t have to change their cooking or heating appliances to take the blend which means less disruption and cost for them.  It is also confirming initial findings that customers don’t notice any difference when using the hydrogen blend.

This study addresses one of knowledge gaps in hydrogen safety science and engineering i.e. a predictive model for calculation of deterministic separation distances defined by the parameters of a blast wave generated by a high-pressure gas storage tank rupture in a fire. An overview of existing methods to calculate stored in a tank internal (mechanical) energy and a blast wave decay is presented. Predictions by the existing technique and an original model developed in this study which accounts for the real gas effects and combustion of the flammable gas released into the air (chemical energy) are compared against experimental data on high-pressure hydrogen tank rupture in the bonfire test. The main reason for a poor predictive capability of the existing models is the absence of combustion contribution to the blast wave strength. The developed methodology is able to reproduce experimental data on a blast wave decay after rupture of a stand-alone hydrogen tank and a tank under a vehicle. In this study the chemical energy is dynamically added to the mechanical energy and is accounted for in the energy-scaled non-dimensional distance. The fraction of the total chemical energy of combustion released to feed the blast wave is 5% and 9% however it is 1.4 and 30 times larger than the mechanical energy in the stand-alone tank test and the under-vehicle tank test respectively. The model is applied as a safety engineering tool to four typical hydrogen storage applications including onboard vehicle storage tanks and a stand-alone refuelling station storage tank. Harm criteria to people and damage criteria for buildings from a blast wave are selected by the authors from literature to demonstrate the calculation of deterministic separation distances. Safety strategies should exclude effects of fire on stationary storage vessels and require thermal protection of on-board storage to prevent dangerous consequences of high-pressure tank rupture in a fire.

This paper describes experimental and numerical modelling results from an investigation into the flammability profiles associated with high pressure hydrogen jets released in close proximity to surfaces. This work was performed under a Transnational Access Agreement activity funded by the European Research Infrastructure project H2FC.<br/>The experimental programme involved ignited and unignited releases of hydrogen at pressures of 150 and 425 barg through nozzles of 1.06 and 0.64 mm respectively. The proximity of the release to a ceiling or the ground was varied and the results compared with an equivalent free-jet test. During the unignited experiments concentration profiles were measured using hydrogen sensors. During the ignited releases thermal radiation was measured using radiometers and an infra-red camera. The results show that the flammable volume and flame length increase when the release is in close proximity to a surface. The increases are quantified and the safety implications discussed.<br/>Selected experiments were modelled using the CFD model FLACS for validation purposes and a comparison of the results is also included in this paper. Similarly to experiments the CFD results show an increase in flammable volume when the release is close to a surface. The unstable atmospheric conditions during the experiments are shown to have a significant impact on the results.

This paper describes an experimental programme on vented hydrogen deflagrations which formed part of the Hyindoor project carried out for the EU Fuel Cells and Hydrogen Joint Undertaking. The purpose of this study was to investigate the validity of analytical models used to calculate overpressures following a low concentration hydrogen deflagration. Other aspects of safety were also investigated such as lateral flame length resulting from explosion venting. The experimental programme included the investigation of vented hydrogen deflagrations from a 31 m3 enclosure with a maximum internal overpressure target of 10 kPa (100 mbar). The explosion relief was provided by lightly covered openings in the roof or sidewalls. Uniform and stratified initial hydrogen distributions were included in the test matrix and the location of the ignition source was also varied. The maximum hydrogen concentration used within the enclosure was 14% v/v. The hydrogen concentration profile within the enclosure was measured as were the internal and external pressures. Infrared video images were obtained of the gases vented during the deflagrations. Findings show that the analytical models were generally conservative for overpressure predictions. Flame lengths were found to be far less than suggested by some guidance. Along with the findings the methodology test conditions and corresponding results are presented.

This paper describes a 1-D numerical model for the prediction of heat and mass transfer through an intumescent paint that is applied to an on-board high-pressure GH2 storage tank. The intumescent paint is treated as a composite system consisting of three general components decomposing in accordance with independent finite reaction rates. A moving mesh that is employed for a better prediction of the expansion process of the intumescent paint is based on the local changes of heat and mass. The numerical model is validated against experiments by Cagliostro et al. (1975). The overall model results are used to estimate effect of intumescent paint on fire resistance of carbon-fibre reinforced GH2 storage.

The HyDeploy Project seeks to address a key issue for UK customers: how to reduce the carbon they emit in heating their homes. The UK has a world class gas grid delivering heat conveniently and safely to over 83% of homes. Emissions could be reduced by lowering the carbon content of gas through blending with hydrogen. Compared with solutions such as heat pumps this means that customers would not need disruptive and expensive changes in their homes. This Network Innovation Competition (NIC) funded project seeks to establish the level of hydrogen that can be safely blended with natural gas for transport and use in a UK network.

Under its Smart Energy Network Demonstration innovation programme Keele University is establishing its electricity and gas networks as facilities to drive forward innovation in the energy sector. The objective of HyDeploy is to trial natural gas blended with potentially up to 20% volume of hydrogen in a part of the Keele gas network. Before any hydrogen can be blended with natural gas in the network the percentage of hydrogen to be delivered must be approved by the Health and Safety Executive (HSE). It must be satisfied that the approved blended gas will be as safe to use as normal gas. Any approval will be given as an exemption to the Gas Safety (Management) Regulations. These regulations ensure the safe use and management of gas through the gas network in the UK. The evidence presented to the HSE comprises critically appraised literature combined with the results from a specifically commissioned experimental and testing programme. Based on engagement with all local customers this includes detailed safety checks on the network appliances and installations at Keele. Subject to approval by the HSE the hydrogen production and grid injection units will be installed and an extensive trial programme of blending will be undertaken. If hydrogen were blended at 20% volume with natural gas across the UK it would save around 6 million tonnes of carbon dioxide emissions every year the equivalent of taking 2.5 million cars off the road.

This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.

Fuel Cell Vehicles (FCVs) are a disruptive innovation and are currently looking towards niche market entry. However commercialisation has been unsuccessful thus far and there is a limited amount of literature that can guide their market entry. In this paper a historical case study is undertaken which looks at Tesla Motors high-end encroachment market entry strategy. FCVs have been compared to Tesla vehicles due to their similarities; both are disruptive innovations both are high cost and both are zero emission vehicles. Therefore this paper looks at what can be learned form Tesla Motors successful market entry strategy and proposes a market entry strategy for FCVs. It was found that FCVs need to enact a paradigm shift from their current market entry strategy to one of high-end encroachment. When this has been achieved FCVs will have greater potential for market penetration.

As the UK’s largest emitter of greenhouse gases the supply of domestic industrial and commercial heat must be decarbonised if the UK is to meet its climate change targets.<br/><br/>This report publishes the outcomes from Phase 1 of the Energy Technologies Institute’s Smart Systems and Heat programme highlighting that for the UK to transition to a low carbon heating system it must understand consumer needs and behaviours while connecting this with the development and integration of technologies and new business models.<br/><br/>Written by the ETI with support from the Energy Systems Catapult this report tackles three interconnected areas: heating needs and controls within the home; heating infrastructure and building retrofit at a local level; and the operation and governance of the whole system.<br/><br/>The research also shows that as part of a low carbon heating system upgrade advanced controls are critical to performance sizing and operating costs enabling smaller appliances and lower peak electricity demands and maximising the efficiency of existing infrastructure. With significant fabric retrofits potentially required in around 10 million of the existing 28 million dwellings in the UK housing stock the report recommends that building new homes to be both very efficient and “low carbon ready” is a low regret decision which should be progressed with some urgency.

In recent years new-found interest in the hydrogen economy from both industry and academia has helped to shed light on its potential. Hydrogen can enable an energy revolution by providing much needed flexibility in renewable energy systems. As a clean energy carrier hydrogen offers a range of benefits for simultaneously decarbonizing the transport residential commercial and industrial sectors. Hydrogen is shown here to have synergies with other low-carbon alternatives and can enable a more cost-effective transition to de-carbonized and cleaner energy systems. This paper presents the opportunities for the use of hydrogen in key sectors of the economy and identifies the benefits and challenges within the hydrogen supply chain for power-to-gas power-to-power and gas-to-gas supply pathways. While industry players have already started the market introduction of hydrogen fuel cell systems including fuel cell electric vehicles and micro-combined heat and power devices the use of hydrogen at grid scale requires the challenges of clean hydrogen production bulk storage and distribution to be resolved. Ultimately greater government support in partnership with industry and academia is still needed to realize hydrogen's potential across all economic sectors.

Link to document download on Royal Society Website

This study is driven by the need to understand requirements to safe blow-down of hydrogen onboard storage tanks through a pressure relief device (PRD) inside a garage-like enclosure with low natural ventilation. Current composite tanks for high pressure hydrogen storage have been shown to rupture in 3.5–6.5 min in fire conditions. As a result a large PRD venting area is currently used to release hydrogen from the tank before its catastrophic failure. However even if unignited the release of hydrogen from such PRDs has been shown in our previous studies to result in unacceptable overpressures within the garage capable of causing major damage and possible collapse of the structure. Thus to prevent collapse of the garage in the case of a malfunction of the PRD and an unignited hydrogen release there is a clear need to increase blow-down time by reducing PRD venting area. Calculations of PRD diameter to safely blow-down storage tanks with inventories of 1 5 and 13 kg hydrogen are considered here for a range of garage volumes and natural ventilation expressed in air changes per hour (ACH). The phenomenological model is used to examine the pressure dynamics within a garage with low natural ventilation down to the known minimum of 0.03 ACH. Thus with moderate hydrogen flow rate from the PRD and small vents providing ventilation of the enclosure there will be only outflow from the garage without any air intake from outside. The PRD diameter which ensures that the pressure in the garage does not exceed a value of 20 kPa (accepted in this study as a safe overpressure for civil structures) was calculated for varying garage volumes and natural ventilation (ACH). The results are presented in the form of simple to use engineering nomograms. The conclusion is drawn that PRDs currently available for hydrogen-powered vehicles should be redesigned along with either a change of requirements for the fire resistance rating or innovative design of the onboard storage system as hydrogen-powered vehicles are intended for garage parking. Further research is needed to develop safety strategies and engineering solutions to tackle the problem of fire resistance of onboard storage tanks and requirements to PRD performance. Regulation codes and standards in the field should address this issue.

Conditions are examined under which mechanical stimuli produced by striking controlled blows can result in sparking and ignition of hydrogen in air mixtures. The investigation principally concerns magnesium thermite reaction as the ignition source and focuses on the conditions and thermomechanical parameters that are involved in determining the probability of ignition. It is concluded that the notion of using the kinetic energy of impact as the main criterion in determining whether an ignition event is likely or not is much less useful than considering the parameters which determine the maximum temperature produced in a mechanical stimuli event. The most influential parameter in determining ignition frequency or probability is the velocity of sliding movement during mechanical stimuli. It is also clear that the kinetic energy of a moving hammer head is of lesser importance than the normal force which is applied during contact. This explains the apparent discrepancy in previous studies between the minimum kinetic energy thought to be necessary to allow thermite sparking and gas ignition to occur with drop weight impacts and glancing blow impacts. In any analysis of the likelihood of mechanical stimuli to cause ignition the maximum surface temperature generated should be determined and considered in relation to the temperatures that would be required to initiate hot surface reactions sufficient to cause sparking and ignition.

The next decade will see fundamental changes in how people heat their homes. The global energy system is changing in response to the need to transition away from fossil-based generation towards more environmentally sustainable alternatives.

Hydrogen offers one such alternative but currently there is limited understanding of public perceptions of hydrogen the information that people need in order to make an informed choice about using hydrogen in their homes and how misunderstandings could present barriers to the uptake of hydrogen technology. This is crucial to ensure the success of future policy and investment. The H21 concept is to convert the UK gas distribution network to 100% hydrogen over time thereby decarbonising heat and supporting decarbonisation of electric large industrials and transport. This would be achieved using the existing UK gas grid network and technology available across the world today whilst maintaining the benefits of gas and the gas networks in the energy mix for the long-term future. Additionally this would maintain choice of energy for customers i.e. they would be able to use both gas and electricity. The H21 project is being delivered by the UK gas distribution networks Northern Gas Networks Cadent Wales & West Utilities and SGN. As part of the H21 project Leeds Beckett University has been working with Northern Gas Networks to gain insight into public perceptions of hydrogen as a domestic fuel. Using innovative social science methods the research team has explored for the first time public perceptions of moving the UK domestic fuel supply to 100% hydrogen. We identify what people think and feel about a potential conversion the concerns and questions that they have and how to address them clearly. The findings presented in this report will ensure that issues around the current perception of hydrogen are identified and addressed prior to any large-scale technology rollout.

The first stage of the project comprised a series of discovery interviews which explored how to talk to people about hydrogen and the H21 project. We interviewed 12 participants selected to ensure we included people with a range of experiences and domestic settings for example people who live in urban and rural areas those who live alone those who live with children or a partner those who live in their own home and those who rent. Most participants had given very little thought about where their gas and electric comes from and other than switching supplier to get a better tariff had very little interest in it. They had not previously considered their domestic heating as a source of carbon emissions and were surprised that there may be a need in the future to change their gas supply. From the discovery interviews we identified several key areas to explore in the next stage of the work:

• Beliefs about the environment
• Beliefs about inconvenience and cost
• Beliefs about safety
• Beliefs about the economic impact

This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.

Bioenergy with carbon capture and storage (BECCS) removes carbon dioxide (CO2) from the atmosphere i.e. negative CO2 emissions. It will likely have an important role in the transition to a net-zero economy by offsetting hard-to-abate greenhouse gas emissions. However there are concerns about the sustainability of large scale BECCS deployment using bioenergy from predominantly primary biomass sources (i.e. dedicated energy crops). Secondary sources of biomass (e.g. waste biomass municipal solid wastes forest/agricultural residues) are potentially an economical and sustainable alternative resource. Furthermore supplementing primary biomass demand with secondary sources could enable the supply of biomass from solely indigenous sources (i.e. from the UK) which could provide economic advantages in a growing global bio-economy.<br/><br/>There is also a growing interest in biomass-derived hydrogen production with CCS (BHCCS) which generates hydrogen and removes CO2 from the atmosphere. Hydrogen could help decarbonise fuel-dependent sectors such as heat industry or transportation. The aim of this study was to determine whether BHCCS could possibly deliver net negative CO2 emissions making comparisons against the other BECCS technologies.

This paper describes a CFD study of a scenario involving the vertical downward release of hydrogen from a thermally-activated pressure relief device (TPRD) under a fuel cell car. The volumetric source model is applied to simulate hydrogen release dynamics during the tank blowdown process. Simulations are conducted for both unignited and ignited releases from onboard storage at 35 MPa and 70 MPa with TPRD orifice 4.2 mm. Results show that after TPRD opening the hazards associated with the release of hydrogen lasts less than two minutes and the most hazardous timeframe occurs within ten seconds of the initiation of the release. The deterministic separation distances for unignited releases are longer than those for ignited releases indicating that the separation distances are dominated by delayed ignition events rather than immediate ignition events. The deterministic separation distances for both unignited and ignited hydrogen downward releases under the car are significantly shorter than those of free jets. To ensure the safety of people a deterministic separation distance of at least 10 m for 35 MPa releases is required. This distance should be increased to 12 m for the 70 MPa release case. To ensure that the concentration of hydrogen is always less than 4% at the location of the air intake of buildings the deterministic separation distance should be at least 11 m for 35 MPa releases and 13 m for 70 MPa releases.