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.