United Kingdom

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.

An experimental study of hydrogen/air premixed flame propagation in a closed rectangular channel with the inhibitions (N2 or CO2) was conducted to investigate the inhibiting effect of N2 and CO2 on the flame properties during its propagation. Both Schlieren system and the pressure sensor were used to capture the evolution of flame shape and pressure changes in the channel. It was found that both N2 and CO2 have considerable inhibiting effect on hydrogen/air premixed flames. Compared with N2 CO2 has more prominent inhibition which has been interpreted from thermal and kinetic standpoints. In all the flames the classic tulip shape was observed. With different inhibitor concentration the flame demonstrated three types of deformation after the classic tulip inversion. A simple theoretical analysis has also been conducted to indicate that the pressure wave generated upon the first flame-wall contact can affect the flame deformation depending on its meeting moment with the flame front. Most importantly the meeting moment is always behind the start of tulip inversion which suggests the non-dominant role of pressure wave on this featured phenomenon.

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%.

<br/>Cyclic Voltammetry Measurements performed on a Cobaloxime Catalyst designed for photochemical hydrogen production.

Hydrogen vehicles may emerge as a leading contender to replace today’s internal combustion engine powered vehicles. A Phenomena Identification and Ranking Table exercise conducted as part of the European Network of Excellence on Hydrogen Safety (HySafe) identified the use of hydrogen vehicles in road tunnels as a topic of important concern. An internal project called HyTunnel was duly established within HySafe to review identify and analyse the issues involved and to contribute to the wider activity to establish the true nature of the hazards posed by hydrogen vehicles in the confined space of a tunnel and their relative severity compared to those posed by vehicles powered by conventional fuels including compressed natural gas (CNG). In addition to reviewing current hydrogen vehicle designs tunnel design practice and previous research a programme of experiments and CFD modelling activities was performed for selected scenarios to examine the dispersion and explosion hazards potentially posed by hydrogen vehicles. Releases from compressed gaseous hydrogen (CGH2) and liquid hydrogen (LH2) powered vehicles have been studied under various tunnel geometries and ventilation regimes. The findings drawn from the limited work done so far indicate that under normal circumstances hydrogen powered vehicles do not pose a significantly higher risk than those powered by petrol diesel or CNG but this needs to be confirmed by further research. In particular obstructions at tunnel ceiling level have been identified as a potential hazard in respect to fast deflagration or even detonation in some circumstances which warrants further investigation. The shape of the tunnel tunnel ventilation and vehicle pressure relief device (PRD) operation are potentially important parameters in determining explosion risks and the appropriate mitigation measures.

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 objectives of the IDEALHY project which receives funding from the European Union’s 7th Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement No. 278177 are to design a novel process that will significantly increase the efficiency of hydrogen liquefaction and be capable of delivering liquid hydrogen at a rate that is an order of magnitude greater than current plants. The liquid hydrogen could then be delivered to refueling stations in road tankers. As part of the project the safety management of the new large scale process and the transportation of liquid hydrogen by road tanker into urban areas are being considered. Effective safety management requires that the hazards are identified and well understood. This paper describes the scope of the safety work within IDEALHY and presents the output of the work completed so far. Initially a review of available experimental data on the hazards posed by releases of liquid hydrogen was undertaken which identified that generally there is a dearth of data relevant to liquid hydrogen releases. Subsequently HAZIDs have been completed for the new liquefaction process storage of liquid hydrogen and its transportation by road. This included a review of incidents relevant to these activities. The principal causes of the incidents have been analysed. Finally the remaining safety work for the IDEALHY project is outlined.

Shipping is a very important source of pollution worldwide. In recent years numerous actions and measures have been developed trying to reduce the levels of greenhouse gases (GHG) from the marine exhaust emissions in the fight against climate change boosting the Sustainable Development Goal 13. Following this target the action of hydrogen as energy vector makes it a suitable alternative to be used as fuel constituting a very promising energy carrier for energy transition and decarbonization in maritime transport. The objective of this study is to develop an ex-ante environmental evaluation of two promising technologies for vessels propulsion a H2 Polymeric Electrolytic Membrane Fuel Cell (PEMFC) and a H2 Internal Combustion Engine (ICE) in order to determine their viability and eligibility compared to the traditional one a diesel ICE. The applied methodology follows the Life Cycle Assessment (LCA) guidelines considering a functional unit of 1 kWh of energy produced. LCA results reveal that both alternatives have great potential to promote the energy transition particularly the H2 ICE. However as technologies readiness level is quite low it was concluded that the assessment has been conducted at a very early stage so their sustainability and environmental performance may change as they become more widely developed and deployed which can be only achieved with political and stakeholder’s involvement and collaboration.

This paper aims to improve prediction capability of the vent sizing correlation presented in the form of functional dependence of the dimensionless deflagration overpressure on the turbulent Bradley number similar to our previous studies. The correlation is essentially upgraded based on recent advancements in understanding and modelling of combustion phenomena relevant to hydrogen-air vented deflagrations and unique large-scale tests carried out by different research groups. The focus is on hydrogen-air deflagrations in low-strength equipment and buildings when the reduced pressure is accepted to be  below 0.1 MPa. The combustion phenomena accounted for by the correlation include: turbulence generated by the flame front itself; leading point mechanism stemming from the preferential diffusion of hydrogen in air in stretched flames; growth of the fractal area of the turbulent flame surface; initial turbulence in the flammable mixture; as well as effects of enclosure aspect ratio and presence of obstacles. The correlation is validated against the widest range of experimental conditions available to date (76 experimental points). The validation covers a wide range of test conditions: different shape enclosures of volume up to 120 m3; initially quiescent and turbulent hydrogen-air mixtures; hydrogen concentration in air from 6% to 30% by volume; ignition source location at enclosure centre near and far from a vent; empty enclosures and enclosures with obstacles.

Emerging hydrogen energy technologies are creating new avenues for bring hydrogen fuel usage into larger public domain. Identification of possible accidental scenarios and measures to mitigate associated hazards should be well understood for establishing best practice guidelines. Accidentally released hydrogen forms flammable mixtures in a very short time. Ignition of such a mixture in congestion and confinements can lead to greater magnitudes of overpressure catastrophic for both structure and people around. Hence understanding of the permissible level of confinements and congestion around the hydrogen fuel handling and storage unit is essential for process safety. In the present study numerical simulations have been performed for the hydrogen-air turbulent deflagration in a well-defined congestion of repeated pipe rig experimentally studied by [1]. Large Eddy Simulations (LES) have been performed using the in-house modified version of the OpenFOAM code. The Flame Surface Wrinkling Model in the LES context is used for modelling deflagrations. Numerical predictions concerning the effects of hydrogen concentration and congestion on turbulent deflagration overpressure are compared with the measurements [1] to provide validation of the code. Further insight about the flame propagation and trends of the generated overpressures over the range of concentrations are discussed.