Netherlands

Direct internal reforming enables optimal heat integration and reduced complexity in solid oxide fuel cell (SOFC) systems but thermal stresses induced by the increased temperature gradients may inflict damage to the stack. Therefore the development of adequate control strategies requires models that can accurately predict the temperature profiles in the stack. A 1D dynamic modelling platform is developed in this study and used to simulate SOFCs in both single cell and stack configurations. The single cell model is used to validate power law and Hougen-Watson reforming kinetics derived from experiments in previous work. The stack model based on the same type of cells accounts for heat transfer in the inactive area and to the environment and is validated with data reported by the manufacturer. The reforming kinetics are then implemented in the stack model to simulate operation with direct internal reforming. Although there are differences between the temperature profiles predicted by the two kinetic models both are more realistic than assuming chemical equilibrium. The results highlight the need to identify rate limiting steps for the reforming and hydrogen oxidation reactions on anodes of functional SOFC assemblies. The modelling approach can be used to study off-design conditions transient operation and system integration as well as to develop adequate energy management and control strategies.

Considering the transition towards the hydrogen economy dependent on hydrogen penetration scenario the cost of a new hydrogen pipeline infrastructure in Europe may amount to several thousands of billions of EURO’s. Therefore the examination of the potential contribution of the existing natural gas assets is a practical and logical first step. As the physical and chemical properties of hydrogen differ significantly from those of natural gas it is not at all possible to simply exchange natural gas by hydrogen in the existing infrastructure. In this paper first a brief overview will be given of the NATURALHY-project. Further the focus will be on the impact of added hydrogen on the performance of existing natural gas domestic end user appliances which is related to the operation of the natural gas grid connecting the different types of appliance. The application of the fundamental insights and carefully designed experiments comparing the behaviour of gases using justified reference conditions have been shown to offer essential progress. The Wobbe index limits of the natural gas distributed pose a first limiting factor upon the maximum allowable hydrogen concentration. Constant-Wobbe index and decreasing-Wobbe index options of H2 admixture have been studied. Considering the appliance light back H2 limiting factor for domestic appliances fuel-rich appliances are the critical ones. Also taking into account stationary gas engines gas turbines industrial applications and natural gas grid management it is not yet justified to present statements on what level of hydrogen concentration could be safely allowed in which specific natural gas distribution region. But more clarity has been obtained on combustion safety aspects of existing domestic appliances on the connection with Wobbe distribution conditions and on the bottlenecks still to be handled.

Although today hydrogen is distributed mainly by trailers in the long terms pipeline distribution will be more suitable if large amounts of hydrogen are produced on industrial scale. Therefore from the safety point of view it is essential to compare hydrogen pipelines to natural gas pipelines which are well established today. Within the paper we compare safety implications in accidental situations. We do not look into technological aspects such as compressors or seals.<br/>Using a CFD (Computational Fluid Dynamics) tool it is possible to investigate the effects of different properties (density diffusivity viscosity and flammability limits) of hydrogen and methane on the dispersion process. In addition CFD tools allow studying the influence of different release scenarios geometrical configurations and atmospheric conditions. An accidental release from a pipeline is modelled. The release is simulated as a flow though a small hole between the high-pressure pipeline and the environment. A part of the pipeline is included in the simulations as high-pressure reservoir. Due to the large pressure difference between the pipeline and the environment the flow conditions at the release become critical.<br/>For the assumed scenarios larger amount of flammable mixture could be observed in case of hydrogen release. On the other hand because of buoyancy and a higher sonic speed at the release the hydrogen clouds are farther from the ground level or buildings than in case of the methane clouds decreasing the probability of ignition and reducing the flame acceleration due to obstacles in case of ignition. Results on the effect of wind in the release scenarios are also described.

Simulation of hydrogen-air mixture explosions in a closed large-scale vessel with uniform and nonuniform mixture compositions was performed by the group of partners within the EC funded project “Hydrogen Safety as an Energy Carrier” (HySafe). Several experiments were conducted previously by Whitehouse et al. in a 10.7 m3 vertically oriented (5.7-m high) cylindrical facility with different hydrogen-air mixture compositions. Two particular experiments were selected for simulation and comparison as a Standard Benchmark Exercise (SBEP) problem: combustion of uniform 12.8% (vol.) hydrogen-air mixture and combustion of non-uniform hydrogen-air mixture with average 12.6% (vol.) hydrogen concentration across the vessel (vertical stratification 27% vol. hydrogen at the top of the vessel 2.5% vol. hydrogen at the bottom of the vessel); both mixtures were ignited at the top of the vessel. The paper presents modelling approaches used by the partners comparison of simulation results against the experiment data and conclusions regarding the non-uniform mixture combustion modelling in real-life applications.

Storage of gases under pressure including hydrogen is a well-known technique. However the use in vehicles of hydrogen at pressures much higher than those applicable in natural gas cars still requires safety and performance studies with respect to the verification of the existing standards and regulations. The JRC-IE has developed a facility GasTeF for carrying out tests on full-scale high pressure vehicle’s tanks for hydrogen or natural gas. Typical tests performed in GasTeF are static permeation measurements of the storage system and hydrogen cycling in which tanks are fast filled and slowly emptied using hydrogen pressurised up to 70 MPa for at least 1000 times according to the requirements of the EU regulation on type-approval of hydrogen-powered motor vehicles. Moreover the temperature evolution of the gas inside and outside the tank is monitored using an ad-hoc designed thermocouples array system. This paper reports the first experimental results on the temperature distribution during hydrogen cycling tests.

The “SUpport to SAfety aNAlysis of Hydrogen and Fuel Cell Technologies (SUSANA)” project aims to support stakeholders using Computational Fluid Dynamics (CFD) for safety engineering design and assessment of FCH systems and infrastructure through the development of a model evaluation protocol. The protocol covers all aspects of safety assessment modelling using CFD from release through dispersion to combustion (self-ignition fires deflagrations detonations and Deflagration to Detonation Transition - DDT) and not only aims to enable users to evaluate models but to inform them of the state of the art and best practices in numerical modelling. The paper gives an overview of the SUSANA project including the main stages of the model evaluation protocol and some results from the on-going benchmarking activities.

Hydrogen sensors are recognized as an important technology for facilitating the safe implementation of hydrogen as an alternative fuel and there are numerous reports of a sensor alarm successfully preventing a potentially serious event. However gaps in sensor metrological specifications as well as in their performance for some applications exist. The U.S. Department of Energy (DOE) Fuel Cell Technologies Office published a short list of critical gaps in the 2007 and 2012 Multiyear Project Plans; more detailed gap analyses were independently performed by the Joint Research Centre (JRC) and the National Renewable Energy Laboratory (NREL). There have been however some significant advances in sensor technologies since these assessments including the commercial availability of hydrogen sensors with fast response times (t90 < 1 s which had been an elusive DOE target since 2007) improved robustness to chemical poisons improved selectivity and improved lifetime and stability. These improvements however have not been universal and typically pertain to select platforms or models. Moreover as hydrogen markets grow and new applications are being explored more demands will be imposed on sensor performance. The hydrogen sensor laboratories at NREL and the JRC are currently updating the hydrogen safety sensor gap analysis through direct interaction with international stakeholders in the hydrogen community especially end users. NREL and the JRC are currently organizing a series of workshops (in Europe and the United States) with sensor developers end-users and other stakeholders in 2017 to identify technology gaps and to develop a path forward to address them. One workshop was held on May 10 in Brussels Belgium at the Headquarters of the Fuel Cell and Hydrogen Joint Undertaking. A second workshop is planned at NREL in Golden CO USA. This paper reviews improvements in sensor technologies in the past 5 to 10 years identifies gaps in sensor performance and use requirements and identifies potential research strategies to address the gaps. The outcomes of the Hydrogen Sensors Workshops are also summarized.

While most hydrogen research focuses on the technical and cost hurdles to a full-scale hydrogen economy little consideration has been given to the geopolitical drivers and consequences of hydrogen developments. The technologies and infrastructures underpinning a hydrogen economy can take markedly different forms and the choice over which pathway to take is the object of competition between different stakeholders and countries. Over time cross-border maritime trade in hydrogen has the potential to fundamentally redraw the geography of global energy trade create a new class of energy exporters and reshape geopolitical relations and alliances between countries. International governance and investments to scale up hydrogen value chains could reduce the risk of market fragmentation carbon lock-in and intensified geo-economic rivalry.

To develop safety strategies for the use of hydrogen indoors the HyIndoor project is studying the behaviour of a hydrogen release deflagration or non-premixed flame in an enclosed space such as a fuel cell or its cabinet a room or a warehouse. The paper proposes a safety approach based on safety objectives that can be used to take various scenarios of hydrogen leaks into account for the safe design of Hydrogen and Fuel Cell (HFC) early market applications. Knowledge gaps on current engineering models and unknown influence of specific parameters were identified and prioritized thereby re-focusing the objectives of the project test campaign and numerical simulations. This approach will enable the improvement of the specification of openings and use of hydrogen sensors for enclosed spaces. The results will be disseminated to all stakeholders including hydrogen industry and RCS bodies.

Short refuelling time and high final state of charge are among the main hydrogen car user's requirements. To meet these requirements without exceeding the tank materials safety limits hydrogen precooling is needed. Filling experiments with different inlet gas temperatures and mass flow rates have been executed using two different types of on-board tanks (type 3 and 4). State of charge has a strong dependency on the inlet gas temperature. This dependency is more visible for type 4 tanks. Lowest precooling temperature (−40 °C) is not always required in order to meet user's requirements so energy savings can be achieved if the initial conditions of the tank are correctly identified. The results of the experiments performed have been compared with the SAE J2601 look-up tables for non-communication fillings. A big safety margin has been observed in these tables. Refuelling could be performed faster and with less demanding precooling requirements if the initial conditions and the configuration of the hydrogen storage system are well known.

Membrane reactors for hydrogen production can increase both the hydrogen production efficiency at small scale and the electric efficiency in micro-cogeneration systems when coupled with Polymeric Electrolyte Membrane fuel cells. This paper discusses the achievements of three European projects (FERRET FluidCELL BIONICO) which investigate the application of the membrane reactor concept to hydrogen production and micro-cogeneration systems using both natural gas and biofuels (biogas and bio-ethanol) as feedstock. The membranes used to selectively separate hydrogen from the other reaction products (CH4 CO2 H2O etc.) are of asymmetric type with a thin layer of Pd alloy (<5 μm) and supported on a ceramic porous material to increase their mechanical stability. In FERRET the flexibility of the membrane reactor under diverse natural gas quality is validated. The reactor is integrated in a micro-CHP system and achieves a net electric efficiency of about 42% (8% points higher than the reference case). In FluidCELL the use of bio-ethanol as feedstock for micro-cogeneration Polymeric Electrolyte Membrane based system is investigated in off-grid applications and a net electric efficiency around 40% is obtained (6% higher than the reference case). Finally BIONICO investigates the hydrogen production from biogas. While BIONICO has just started FERRET and FluidCELL are in their third year and the two prototypes are close to be tested confirming the potentiality of membrane reactor technology at small scale.

Tensile and fatigue tests were performed on an AA2198 aluminum alloy in the T851 condition in ambient air and liquid hydrogen (LH2). All fatigue tests were performed under load control at a frequency of 20 Hz and a stress ratio of R=0.1. The Gecks-Och-Function [1] was fitted on the measured cyclic lifetimes.<br/><br/>The tensile strength in LH2 was measured to be 46 % higher compared to the value determined at ambient conditions and the fatigue limit was increased by approximately 60 %. Both S-N curves show a distinct S-shape but also significant differences. Under LH2 environment the transition from LCF- to HCF-region as well as the transition to the fatigue limit is shifted to higher cyclic lifetimes compared to ambient test results. The investigation of the crack surfaces showed distinct differences between ambient and LH2 conditions. These observed differences are important factors in the fatigue behavior change.

Interest in hydrogen as a carbon-neutral energy carrier is on the rise around the globe including in Europe. In particular power-to-gas as a technology to transform electricity to hydrogen is receiving ample attention. This article scrutinises current updates in the energy law framework of the EU to explain the legal pre-conditions for the various possible applications of power-to-gas technology. It highlights the influence of both electricity and gas legislation on conversion storage and transmission of hydrogen and demonstrates why ‘green’ hydrogen might come with certain legal privileges under the Renewable Energy Directive attached to it as opposed to the European Commission’s so-called ‘clean’ hydrogen. The article concludes by advocating for legal system integration in EU energy law namely merging the currently distinct EU electricity and gas law frameworks into one unified EU Energy Act.

A promising option for storing large-scale quantities of green gases (e.g. hydrogen) is in subsurface rock salt caverns. The mechanical performance of salt caverns utilized for long-term subsurface energy storage plays a signifcant role in long-term stability and serviceability. However rock salt undergoes non-linear creep deformation due to long-term loading caused by subsurface storage. Salt caverns have complex geometries and the geological domain surrounding salt caverns has a vast amount of material heterogeneity. To safely store gases in caverns a thorough analysis of the geological domain becomes crucial. To date few studies have attempted to analyze the infuence of geometrical and material heterogeneity on the state of stress in salt caverns subjected to long-term loading. In this work we present a rigorous and systematic modeling study to quantify the impact of heterogeneity on the deformation of salt caverns and quantify the state of stress around the caverns. A 2D fnite element simulator was developed to consistently account for the non-linear creep deformation and also to model tertiary creep. The computational scheme was benchmarked with the already existing experimental study. The impact of cyclic loading on the cavern was studied considering maximum and minimum pressure that depends on lithostatic pressure. The infuence of geometric heterogeneity such as irregularly-shaped caverns and material heterogeneity which involves diferent elastic and creep properties of the diferent materials in the geological domain is rigorously studied and quantifed. Moreover multi-cavern simulations are conducted to investigate the infuence of a cavern on the adjacent caverns. An elaborate sensitivity analysis of parameters involved with creep and damage constitutive laws is performed to understand the infuence of creep and damage on deformation and stress evolution around the salt cavern confgurations.

This paper presents the results of a demonstration project including building-integrated photovoltaic (BIPV) solar panels a residential building and a hydrogen fuel cell electric vehicle (FCEV) for combined mobility and power generation aiming to achieve a net zero-energy residential building target. The experiment was conducted as part of the Car as Power Plant project at The Green Village in the Netherlands. The main objective was to assess the end-user’s potential of implementing FCEVs in vehicle-to-grid operation (FCEV2G) to act as a local energy source. FCEV2G field test performance with a Hyundai ix35 FCEV are presented. The car was adapted using a power output socket capable of delivering up to 10 kW direct current (DC) to the alternating current (AC) national grid when parked via an off-board (grid-tie) inverter. A Tank-To-AC-Grid efficiency (analogous to Tank- To-Wheel efficiency when driving) of 44% (measured on a Higher Heating Value basis) was obtained when the car was operating in vehicle-to-grid (V2G) mode at the maximum power output. By collecting and analysing real data on the FCEV power production in V2G mode and on BIPV production and household consumption two different operating modes for the FCEV offering balanced services to a residential microgrid were identified namely fixed power output and load following. Based on the data collected one-year simulations of a microgrid consisting of 10 all-electric dwellings and 5 cars with the different FCEV2G modes of operation were performed. Simulation results were evaluated on the factors of autonomy self-consumption of locally produced energy and net-energy consumption by implementing different energy indicators. The results show that utilizing an FCEV working in V2G mode can reduce the annual imported electricity from the grid by approximately 71% over one year and aiding the buildings in the microgrid to achieve a net zero-energy building target. Furthermore the simulation results show that utilizing the FCEV2G setup in both modes analysed could be economically beneficial for the end-user if hydrogen prices at the pump fall below 8.24 €/kg.

The role of hydrogen in future energy systems is widely acknowledged: from fuel for difficult-to-decarbonize applications to feedstock for chemicals synthesis to energy storage for high penetration of undispatchable renewable electricity. While several literature studies investigate such energy systems the details of how electrolysers and renewable technologies optimally behave and interact remain an open question. With this work we study the interplay between (i) renewable electricity generation through wind and solar (ii) electricity storage in batteries (iii) electricity storage via Power-to-H2 and (iv) hydrogen commodity demand. We do so by designing a cost-optimal zero-emission energy system and use the Netherlands as a case study in a mixed integer linear model with hourly resolution for a time horizon of one year. To account for the significant role of wind we also provide an elaborate approach to model broad portfolios of wind turbines. The results show that if electrolyzers can operate flexibly batteries and power-to-H2-to-power are complementary with the latter using renewable power peaks and the former using lower renewable power outputs. If the operating modes of the power-to-H2-to-power system are limited - artificially or technically - the competitive advantage over batteries decreases. The preference of electrolyzers for power peaks also leads to an increase in renewable energy utilization for increased levels of operation flexibility highlighting the importance of capturing this feature both from a technical and a modeling perspective. When adding a commodity hydrogen demand the amount of hydrogen converted to electricity decreases hence decreasing its role as electricity storage medium.

This paper proposes an integration of concentrating solar power (CSP) with a sorption-enhanced steam methane reforming (SE-SMR) process and assesses its overall solar-to-fuel conversion performance. A thermodynamic treatment of the SE-SMR process for H2 production is presented and evaluated in an innovative two reactors system configuration using CSP as a heat input. Four metal carbonate/metal oxide pairs are considered and the equilibrium thermodynamics reveals that CaCO3/CaO pair is the most suitable candidate for this process. Additionally a reactor-scale thermodynamic model is developed to determine the optimum operating conditions for the process. For the carbonation step temperatures between 700 and 900 K and steam-to-methane ratio ≥4 are found to be the most favorable. Furthermore an advanced process model which utilizes operating conditions determined from the reactor-scale model is developed to evaluate the process efficiency. The model predicts that the proposed process can achieve a solar-to-fuel efficiency ~41% for calcination temperature of 1500 K and carbonation temperature of 800 K without considering any solid heat recovery. An additional 2.5% increase in the process efficiency is feasible with the consideration of the solid heat recovery. This study shows the thermodynamic feasibility of integrating the SE-SMR process with CSP technologies.

The design and operation of integrated multi-energy systems require models that adequately describe the behavior of conversion and storage technologies. Typically linear conversion performance or fixed data from technology manufacturers are employed especially for new or advanced technologies. This contribution provides a new modeling framework for electrochemical devices that bridges first-principles models to their simplified implementation in the optimization routine. First thermodynamic models are implemented to determine the on/off-design performance and dynamic behavior of different types of fuel cells and of electrolyzers. Then as such nonlinear models are intractable for use in the optimization of integrated systems different linear approximations are developed. The proposed strategies for the synthesis of reduced order models are compared to assess the impact of modeling approximations on the optimal design of multi-energy systems including fuel cells and electrolyzers. This allows to determine the most suitable level of detail for modeling the underlying electrochemical technologies from an integrated system perspective. It is found that the approximation methodology affects both the design and operation of the system with a significant effect on system costs and violation of the thermal energy demand. Finally the optimization and technology modeling framework is exploited to determine guidelines for the installation of the most suitable fuel cell technology in decentralized multi-energy systems. We show how the installation costs of PEMFC SOFC and MCFC their electrical and thermal efficiencies their conversion dynamics and the electricity price affect the system design and technology selection.

To achieve the Paris Agreement’s long-term temperature goal current energy systems must be transformed. Australia represents an interesting case for energy system transformation modelling: with a power system dominated by fossil fuels and specifically with a heavy coal component there is at the same time a vast potential for expansion and use of renewables. We used the multi-sectoral Australian Energy Modelling System (AUSeMOSYS) to perform an integrated analysis of implications for the electricity transport and selected industry sectors to the mid-century. The state-level resolution allows representation of regional discrepancies in renewable supply and the quantification of inter-regional grid extensions necessary for the physical integration of variable renewables. We investigated the impacts of different CO₂ budgets and selected key factors on energy system transformation. Results indicate that coal-fired generation has to be phased out completely by 2030 and a fully renewable electricity supply achieved in the 2030s according to the cost-optimal pathway implied by the 1.5 °C Paris Agreement-compatible carbon budget. Wind and solar PV can play a dominant role in decarbonizing Australia’s energy system with continuous growth of demand due to the strong electrification of linked energy sectors.

Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys supports deposition/production techniques etc. High flux and cheap membranes yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly when employing the membranes in fluidized bed reactors the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes resistance to hydrogen embrittlement and stability at high temperature.

An ultra low carbon (ULC) steel was subjected to electrochemical hydrogen charging to provoke hydrogen induced damage in the material. The damage characteristics were analyzed for recrystallized partially recrystallized and cold deformed material. The goal of the study is to understand the effect of cold deformation on the hydrogen induced cracking behavior of a material which is subjected to cathodic hydrogen charging. Additionally charging conditions i.e. charging time and current density were varied in order to identify correlations between on the one hand crack initiation and propagation and on the other hand the charging conditions. The obtained hydrogen induced cracks were studied by optical microscopy scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Hydrogen induced cracks were observed to propagate transgranularly independently of the state of the material. Deformed samples were considerably more sensitive to hydrogen induced cracking which implies the important role of dislocations in hydrogen induced damage mechanisms.

The current global consumption of natural gas as a fuel is roughly 4 trillion cubic meters per year. In terms of energy the demand for natural gas exceeds the global demand for fossil fuels for transportation. Despite this observation the challenges to natural gas end use that arise when changing the composition of the fuel are largely absent from public policy and research agendas whereas for transportation fuels the issues are more appreciated. Natural gas is delivered via complex networks of interconnected pipelines to end users for direct and indirect heating in household and industrial sectors and for power generation. This interconnectedness is a crucial aspect of the challenge for introducing new fuels.<br/>In this paper we discuss the issues that arise from changing fuel properties for an existing population of end-use equipment. To illustrate the issues we will consider the changes in (combustion) performance of domestic combustion equipment and gas engines for power generation in response to substituting natural gas by hydrogen or hydrogen/natural gas blends. During the discussion we shall also indicate methods for characterizing the properties of the fuel and identify the combustion challenges that must be addressed for a successful transition from the current fuel mix to whatever the future mix may be.

As the EU energy system transitions to low carbon the technology choices should consider a broader set of criteria. The use of Life Cycle Assessment (LCA) prevents burden shift across life cycle stages or impact categories while the use of Energy System Models (ESM) allows evaluating alternative policies capacity evolution and covering all the sectors. This study does an ex-post LCA analysis of results from JRC-EU-TIMES and estimates the environmental impact indicators across 18 categories in scenarios that achieve 80–95% CO₂ emission reduction by 2050. Results indicate that indirect CO₂ emissions can be as large as direct ones for an 80% CO₂ reduction target and up to three times as large for 95% CO₂ reduction. Impact across most categories decreases by 20–40% as the CO₂ emission target becomes stricter. However toxicity related impacts can become 35–100% higher. The integrated framework was also used to evaluate the Power-to-Methane (PtM) system to relate the electricity mix and various CO₂ sources to the PtM environmental impact. To be more attractive than natural gas the climate change impact of the electricity used for PtM should be 123–181 gCO₂eq/kWh when the CO₂ comes from air or biogenic sources and 4–62 gCO₂eq/kWh if the CO₂ is from fossil fuels. PtM can have an impact up to 10 times larger for impact categories other than climate change. A system without PtM results in ~4% higher climate change impact and 9% higher fossil depletion while having 5–15% lower impact for most of the other categories. This is based on a scenario where 9 parameters favor PtM deployment and establishes the upper bound of the environmental impact PtM can have. Further studies should work towards integrating LCA feedback into ESM and standardizing the methodology.

During the filling of hydrogen tanks high temperatures can be generated inside the vessel because of the gas compression while during the emptying low temperatures can be reached because of the gas expansion. The design temperature range goes from −40 °C to 85 °C. Temperatures outside that range could affect the mechanical properties of the tank materials. CFD analyses of the filling and emptying processes have been performed in the HyTransfer project. To assess the accuracy of the CFD model the simulation results have been compared with new experimental data for different filling and emptying strategies. The comparison between experiments and simulations is shown for the temperatures of the gas inside the tank for the temperatures at the interface between the liner and the composite material and for the temperatures on the external surface of the vessel.

Gas sensors are applied for facilitating the safe use of hydrogen in for example fuel cell and hydrogen fuelled vehicles. New sensor developments aimed at meeting the increasingly stringent performance requirements in emerging applications are presented based on in-house technical developments and a literature study. The strategy of combining different detection principles i.e. sensors based on electrochemical cells semiconductors or field effects in combination with thermal conductivity sensor or catalytic combustion elements in one new measuring system is reported. This extends the dynamic measuring range of the sensor while improving sensor reliability to achieve higher safety integrity through diverse redundancy. The application of new nanoscaled materials nano wires carbon tubes and graphene as well as the improvements in electronic components of field-effect resistive-type and optical systems are evaluated in view of key operating parameters such as sensor response time low energy consumption and low working temperature.