Norway

Development of efficient and affordable photocatalysts is of great significance for energy production and environmental sustainability. Transition metal chalcogenides (TMCs) with particle sizes in the 1–100 nm have been used for various applications such as photocatalysis photovoltaic and energy storage due to their quantum confinement effect optoelectronic behavior and their stability. In particular TMCs and their heterostructures have great potential as an emerging inexpensive and sustainable alternative to metal-based catalysts for hydrogen evolution. Herein the methods used for the fabrication of TMCs characterization techniques employed and the different methods of solar hydrogen production by using different TMCs as photocatalyst are reviewed. This review provides a summary of TMC photocatalysts for hydrogen production.

The paper applies the multi-level perspective (MLP) in a descriptive study of three Norwegian ports to shed new light on the sociotechnical processes that structure their efforts to develop into zero emission energy hubs. While exogenous pressures cause tensions over port governance the studied ports utilize their full spectre of functions; as landlords operators authorities and community managers to enable transition. The respective approaches vary related to their local context market situation and social networks including port's relations with their owners. Individual orientations and organizational capacity further influence their engagement with radical innovation niches (e.g. OPS hydrogen LNG). The study highlights the active role of ports in sustainability transition. It shows how the interaction between geographical factors and institutional work influences the scope for new solutions around the individual port and how this makes for different feedback loops and contributions to sustainability transition in wider transport and energy systems.

This paper describes a series of numerical simulations with release and ignition of hydrogen. The objective of this work was to re-investigate the accidental explosion in an ammonia plant which happened in Norway in 1985 with modern CFD tools. The severe hydrogen-air explosion led to two fatalities and complete destruction of the factory building where the explosion occurred. A case history of the accident was presented at the 1.st ICHS in Pisa 2005.<br/>The numerical simulations have been performed with FLACS a commercial CFD simulation tool for gas dispersion and gas explosions. The code has in the recent years been validated in the area of hydrogen dispersion and explosions.<br/>The factory building was 100 m long 10 m wide and 7 m high. A blown-out gasket in a water pump led to release of hydrogen from a large reservoir storing gaseous hydrogen at 3.0 MPa. The accident report estimated a total mass of released hydrogen between 10 and 20 kg. The location of the faulty gasket is known but the direction of the accidental release is not well known and has been one of the topics of our investigations. Several simulations have been performed to investigate the mixing process of hydrogen-air clouds and the development of a flammable gas cloud inside the factory building resulting in a simulation matrix with dispersions in all axis directions. Simulations of ignition of the different gas clouds were carried out and resulting pressure examined. These results have been compared with the damages observed during the accident investigation.<br/>We have also performed FLACS simulations to study the effect of natural venting and level of congestion. The height of the longitudinal walls has been varied leading to different vent openings at floor level at the ceiling and a combination of the two. This was done to investigate the effects of congestion with regards to gas cloud formation.<br/>The base case simulation appears to be in good accordance to the observed damages from the accident. The simulations also show that the build up of the gas cloud strongly depends on the direction of the jet and degree of ventilation. The CFD study has given new insights to the accident and the results are a clear reminder of the importance of natural venting in hydrogen safety.

Potential risk exposure of 3rd parties i.e. people not involved in the actual operation of a plant is often a critical factor to gain authority approval and public acceptance for a development project. This is also highly relevant for development of demonstration facilities for hydrogen production and refuelling infrastructure. This paper presents and discusses results for risk exposure of 3rd parties based on risk assessment studies performed for the planned Hydrogen Technology Research Centre Hytrec in Trondheim. The methodology applied is outlined. Key assumptions and study uncertainties are identified and how these might affect the results are discussed.<br/>The purpose of Hytrec is to build a centre for research development and demonstration of hydrogen as an energy carrier. Hydrogen will be produced both by reforming of natural gas with CO2 capture and by electrolysis of water. The plant also includes a SOFC that will run on natural gas or hydrogen and produce heat and electricity for the Hytrec visitor centre. Hytrec will be located in a populated area without access control. Most of the units will be located within cabinets and modules.<br/>The authors acknowledge the Hytrec project and the Hytrec project partners Statoil Statkraft and DNV for their support and for allowing utilisation of results from the Hytrec QRA in this paper.

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.

We use a detailed solid oxide fuel cell (SOFC) model for micro-grid applications to analyze the effect of failure and degradation on system performance. Design and operational constraints on a component and system level are presented. A degrees of freedom analysis identifies controlled and manipulated system variables which are important for control. Experimental data are included to model complex degradation phenomena of the SOFC unit. Rather than using a constant value a spatially distributed degradation rate as function of temperature and current density is used that allows to study trajectory based performance deterioration. The SOFC unit is assumed to consist of multiple stacks. The failure scenario studied is the loss of one individual SOFC stack e.g. due to breakage of sealing or a series of fuel cells. Simulations reveal that degradation leads to significant drifts from the design operating point. Moreover failure of individual stacks may bring the still operating power generation unit into a regime where further failures and accelerated degradation is more likely. It is shown that system design dimensioning operation and control are strongly linked. Apart from specific quantitative results perhaps the main practical contribution are the collected constraints and the degrees of freedom analysis.

The growing number of hydrogen fillings stations and cars increases the need for accurate models to determine risk. The effect on hydrogen flame length was measured by varying the diameter of the spouting nozzle downstream from the chocked nozzle upstream. The results was compared with an existing model for flame length estimations. The experimental rig was setup with sensors that measured accurately temperature mass flow heat radiation and the pressure range from 0.1 to 11 MPa. The flame length was determined with an in-house developed image-processing tool which analyzed a high-speed film of the each experiment. Results show that the nozzle geometry can cause a deviation as high as 50% compared to estimated flame lengths by the model if wrong assumptions are made. Discharge coefficients for different nozzles has been calculated and presented.

This paper summarises the results from a blind-prediction study for models developed for estimating the consequences of vented hydrogen deflagrations. The work is part of the project Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations (HySEA). The scenarios selected for the blind-prediction entailed vented explosions with homogeneous hydrogen-air mixtures in a 20-foot ISO container. The test program included two configurations and six experiments i.e. three repeated tests for each scenario. The comparison between experimental results and model predictions reveals reasonable agreement for some of the models and significant discrepancies for others. It is foreseen that the first blind-prediction study in the HySEA project will motivate developers to improve their models and to update guidelines for users of the models.

Hydrogen is a valuable option of clean fuel to keep the global temperature rise below 2°C. However one of the main barriers in its transport and use is to ensure safety levels that are comparable with traditional fuels. In particular liquid hydrogen accidents may not be fully understood (yet) and excluded by relevant risk assessment. For instance as hydrogen is cryogenically liquefied to increase its energy density during transport Boiling Liquid Expanding Vapor Explosions (BLEVE) is a potential and critical event that is important addressing in the hazard identification phase. Two past BLEVE accidents involving liquid hydrogen support such thesis. For this reason results from consequence analysis of hydrogen BLEVE will not only improve the understanding of the related physical phenomenon but also influence future risk assessment studies. This study aims to show the extent of consequence analysis influence on overall quantitative risk assessment of hydrogen technologies and propose a systematic approach for integration of overall results. The Dynamic Procedure for Atypical Scenario Identification (DyPASI) is used for this purpose. The work specifically focuses on consequence models that are originally developed for other substances and adapted for liquid hydrogen. Particular attention is given to the parameters affecting the magnitude of the accident as currently investigated by a number of research projects on hydrogen safety worldwide. A representative example of consequence analysis for liquid hydrogen release is employed in this study. Critical conditions detected by the numerical simulation models are accurately identified and considered for subsequent update of the overall system risk assessment.

According to European Directive 2014/94/EU hydrogen providers have the responsibility to prove that their hydrogen is of suitable quality for fuel cell vehicles. Contaminants may originate from hydrogen production transportation refuelling station or maintenance operation. This study investigated the probability of presence of the 13 gaseous contaminants (ISO 14687-2) in hydrogen on 3 production processes: steam methane reforming (SMR) process with pressure swing adsorption (PSA) chlor-alkali membrane electrolysis process and water proton exchange membrane electrolysis process with temperature swing adsorption. The rationale behind the probability of contaminant presence according to process knowledge and existing barriers is highlighted. No contaminant was identified as possible or frequent for the three production processes except oxygen (frequent for chlor-alkali membrane process) carbon monoxide (frequent) and nitrogen (possible) for SMR with PSA. Based on it a hydrogen quality assurance plan following ISO 19880-8 can be devised to support hydrogen providers in monitoring the relevant contaminants.