- Home
- A-Z Publications
- Publications
Publications
Hydrogen Infrastructure Project Risks in The Netherlands
Sep 2021
Publication
This study aims to assess the potential risks of setting up a hydrogen infrastructure in the Netherlands. An integrated risk assessment framework capable of analyzing projects identifying risks and comparing projects is used to identify and analyze the main risks in the upcoming Dutch hydrogen infrastructure project. A time multiplier is added to the framework to develop parameters. The impact of the different risk categories provided by the integrated framework is calculated using the discounted cash flow (DCF) model. Despite resource risks having the highest impact scope risks are shown to be the most prominent in the hydrogen infrastructure project. To present the DCF model results a risk assessment matrix is constructed. Compared to the conventional Risk Assessment Matrix (RAM) used to present project risks this matrix presents additional information in terms of the internal rate of return and risk specifics.
Quantitative Monitoring of the Environmental Hydrogen Embrittlement of Al-Zn-Mg-based Aluminum Alloys via Dnyamic Hydrogen Detection and Digital Image Correlation
Mar 2021
Publication
In this study a novel analytical system was developed to monitor the environmental hydrogen embrittlement of Al-Zn-Mg-based aluminum alloys dynamically and quantitatively under atmospheric air pressure. The system involves gas chromatography using a SnO2-based semiconductor hydrogen sensor a digital image correlation step and the use of a slow strain rate testing machine. Use of this system revealed that hydrogen atoms are generated during the plastic deformation of Al-Zn-Mg alloys caused by the chemical reaction between the water vapor in air and the alloy surface without oxide films. Digital image correlation also clarified that the generated hydrogen atoms caused numerous localized grain boundary cracks on the specimen surface resulting in a localized grain boundary fracture. The amount of hydrogen atoms evolved from the embrittled fracture surface was 2.7 times as high as that from the surface without embrittlement.
Effects of Renewable Energy Unstable Source to Hydrogen Production: Safety Considerations
Sep 2021
Publication
Hydrogen is considered a promising energy carrier for a sustainable future when it is produced by utilizing renewable energy. Nowadays less than 4% of hydrogen production is based on electrolysis processes. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way hydrogen produced by electrolysis processes can be competitive with the conventional fossil energy sources. As conventional electrolysers are designed for operation at fixed process conditions the implementation of fluctuating and highly intermittent renewable energy is challenging. Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. At low power availability conventional alkaline water electrolysers show a limited part-load range due to an increased gas impurity. Explosive mixtures of hydrogen and oxygen must be prevented; thus a safety shutdown is performed when reaching specific gas contamination. The University of Pisa is setting up a dedicated laboratory including a 40-kW commercial alkaline electrolyser: the focus of the study is to analyze the safety of the electrolyser together with its performance and the real energy efficiency analyzing its operational data collected under different operating conditions affected by the unstable energy supply.
Onshore, Offshore or In-turbine Electrolysis? Techno-economic Overview of Alternative Integration Designs for Green Hydrogen Production into Offshore Wind Power Hubs
Aug 2021
Publication
Massive investments in offshore wind power generate significant challenges on how this electricity will be integrated into the incumbent energy systems. In this context green hydrogen produced by offshore wind emerges as a promising solution to remove barriers towards a carbon-free economy in Europe and beyond. Motivated by the recent developments in Denmark with the decision to construct the world’s first artificial Offshore Energy Hub this paper investigates how the lowest cost for green hydrogen can be achieved. A model proposing an integrated design of the hydrogen and offshore electric power infrastructure determining the levelised costs of both hydrogen and electricity is proposed. The economic feasibility of hydrogen production from 2 Offshore Wind Power Hubs is evaluated considering the combination of different electrolyser placements technologies and modes of operations. The results show that costs down to 2.4 €/kg can be achieved for green hydrogen production offshore competitive with the hydrogen costs currently produced by natural gas. Moreover a reduction of up to 13% of the cost of wind electricity is registered when an electrolyser is installed offshore shaving the peak loads.
THyGA - Overview of Relevant Existing Certification Experience and On-going Standardization Activities in the EU and Elsewhere Related to Gas Appliances Using H2NG
Oct 2021
Publication
This 2nd deliverable from WP4 gives an overview of relevant existing certification experience on-going standardization activities and field trials in the European Union and other countries regarding gas appliances using H2NG. It gives a picture of the today’s situation as many of the identified initiatives are ongoing and progressing continuously.
A Catalyst Fusible Link for Hydrogen Detection and Activation of Passive Ventilation Systems
Sep 2021
Publication
This paper presents an experimental study of a hydrogen fusible link developed for use in the detection of hydrogen and in the activation of passive ventilation or other safety systems. Fusible links are commonly used to passively close fire dampers in the event of a fire; they generally consist of two pieces of metal joined together by a low temperature alloy to form a single device. When exposed to fire the link will heat up and eventually melt the alloy causing the metal pieces to separate. The same principle has been adopted for the hydrogen fusible link in which hydrogen recombiner catalyst was coated onto small rectangular brass plates. These plates were then soldered together to create prototypes of the hydrogen fusible link. When the resulting link is exposed to a hydrogen-air mixture an exothermic reaction occurs on the catalyst surface that will heat up the link and melt the solder separating the two sections of the hydrogen fusible link. A series of experiments was performed to characterize the thermal response of the hydrogen fusible links to various hydrogen-air mixtures. The effect of both hydrogen concentration and its rate of accumulation on the increase of catalyst temperature was examined. This study demonstrated the applicability of the hydrogen fusible link for managing hydrogen risk.
The Upfront Cost of Decarbonising Your Home
Nov 2021
Publication
The objective of this report is to analyse the upfront capital costs facing consumers when considering the installation of new low carbon heating technology solutions for their homes today including the cost of any associated home upgrades that will likely be required. The UK Government have recently published its Heat and Buildings Strategy which sets out plans to significantly cut carbon emissions from the existing housing stock and new homes. Whilst the Strategy points to a future role for a variety of technologies such as heat pumps hydrogen and heat networks the success of this Strategy will largely be determined by the ability to achieve installed cost reductions for heat pumps of at least 25-50% by 2025 with the view to achieving cost parity with a gas boiler by 2030. The purpose of this report is to launch a series which tracks the upfront costs of these respective technologies over time to establish whether the cost reduction targets mooted by government and heat pump stakeholders are being delivered and the implications this has on our ability to decarbonise the UK housing stock.
Solar Fuel Processing: Comparative Mini-review on Research, Technology Development, and Scaling
Oct 2022
Publication
Solar energy provides an unprecedented potential as a renewable and sustainable energy resource and will substantially reshape our future energy economy. It is not only useful in producing electricity but also (hightemperature) heat and fuel both required for non-electrifiable energy services. Fuels are particularly valuable as they are energy dense and storable and they can also act as a feedstock for the chemical industry. Technical pathways for the processing of solar fuels include thermal pathways (e.g. solar thermochemistry) photo pathways (e.g. photoelectrochemistry) and combinations thereof. A review of theoretical limits indicates that all technical solar fuel processing pathways have the potential for competitive solar-to-fuel efficiencies (>10 %) but require very different operating conditions (e.g. temperature levels or oxygen partial pressures) making them complementary and highly versatile for process integration. Progress in photoelectrochemical devices and solar thermochemical reactors over the last 50 + years are summarized showing encouraging trends in terms of performance technological viability and scaling.
Assessment of the Economic Efficiency of the Operation of Low-Emission and Zero-Emission Vehicles in Public Transport in the Countries of the Visegrad Group
Nov 2021
Publication
Transport is one of the key sectors of the European economy. However the intensive development of transport caused negative effects in the form of an increase in the emission of harmful substances. The particularly dramatic situation took place in the V4 countries. This made it necessary to implement solutions reducing emissions in transport including passenger transport. Such activities can be implemented in the field of implementation of low-emission and zero-emission vehicles for use. That is why the European Union and the governments of the Visegrad Group countries have developed numerous recommendations communications laws and strategies that order carriers to implement low- and zero-emission mobility. Therefore transport organizers and communication operators faced the choice of the type of buses. From an economic point of view each entrepreneur is guided by the economic efficiency of the vehicles used. Hence the main aim of the article was to conduct an economic evaluation of the operational efficiency of ecological vehicles. As more than 70% of vehicles in use in the European Union are still diesel driven the economic efficiency assessment was also made for vehicles with traditional diesel drive. To conduct the research the method of calculating the total cost of ownership of vehicles in operation was used. As a result of the research it was found that electric buses are the cheapest in the entire period of use (15 years) and then those powered by CNG. On the other hand the cost of using hydrogen buses is the highest. This is due to the high purchase prices of these vehicles. However the EU as well as the governments of individual countries support enterprises and communication operators by offering them financing for investments. The impact of the forecasted fuel and energy prices and the planned inflation on operating costs was also examined. In this case the analyses showed that the forecasted changes in fuel and energy prices as well as the expected inflation will significantly affect the costs of vehicle operation and the economic efficiency of using various types of drives. These changes will have a positive impact on the implementation of zero-emission vehicles into exploitation. Based on the analyses it was found that in 2035 hydrogen buses will have the lowest operating costs.
Establishing the State of the Art for the Definition of Safety Distances for Hydrogen Refuelling Stations
Sep 2021
Publication
Hydrogen is widely considered a clean source of energy from the viewpoint of reduction in carbon dioxide emissions as a countermeasure against global warming and air pollution. Various efforts have been made to develop hydrogen as a viable energy carrier including the implementation of fuel cell vehicles (FCVs) and hydrogen refuelling stations (HRSs). A good network of hydrogen refuelling stations is essential for operating FCVs and several hydrogen refuelling stations have been constructed and are in operation worldwide [1]. However despite the potential benefits of hydrogen its flammability creates significant safety concerns. Furthermore even though the energy density of hydrogen is lower than that of gasoline and there is no carbon present which means the amount of radiant heat flux released during combustion is relatively small hydrogen must be handled at high pressure in order to make the cruising range of a fuel cell vehicle (FCV) equal to that of gasoline-powered vehicles. Therefore it is essential to properly evaluate these safety concerns and take reasonable and effective countermeasures. Approximately 50 accidents and incidents involving HRSs have been reported globally [2]. Sakamoto et al. [2] analysed accidents and incidents at HRSs in Japan and the USA to identify the safety issues. Most types of accidents and incidents are small leakages of hydrogen but some have led to serious consequences such as fire and explosion. Recently there was a serious incident in Norway at Kjørbo where a strong explosion was observed [3] – indeed this was within a short time of two other serious incidents in the USA and South Korea showing that the frequency of such incidents may be higher as deployments increase. Use of hydrogen forklifts (and the associated refuelling infrastructure) is another challenge to consider. Hydrogen refuelling stations are often installed in urban areas facing roads and are readily accessible to everyone. Therefore a key measure to approve the hydrogen refuelling stations is safety distances between the hydrogen infrastructure and the surrounding structures such as office buildings or residential dwellings. Whilst a lot of work has been carried out on safety distances (see e.g. [4-6) the accident scenario assumptions and safety distances varied widely in those studies. As a result no consensus has yet emerged on the safety distances to be used and efforts are still needed to bridge the gap between international standards and local regulations (see e.g. [7-8]). The paper analyses this issue and provides guidance on the way forward.
Blast Wave Generated by Delayed Ignition of Under-Expanded Hydrogen Free Jet at Ambient and Cryogenic Temperatures
Nov 2022
Publication
An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data. The dimensionless blast wave overpressure generated by delayed ignition and the follow-up deflagration or detonation of hydrogen jets at an any location from the jet ∆Pexp/P0 is correlated to the original dimensionless parameter composed of the product of the dimensionless ratio of storage pressure to atmospheric pressure Ps/P0 and the ratio of the jet release nozzle diameter to the distance from the centre of location of the fast-burning near-stoichiometric mixture on the jet axis (30% of hydrogen in the air by volume) to the location of a target (personnel or property) d/Rw. The correlation is built using the analysis of 78 experiments regarding this phenomenon in the wide range of hydrogen storage pressure of 0.5–65.0 MPa and release diameter of 0.5–52.5 mm. The correlation is applicable to hydrogen free jets at ambient and cryogenic temperatures. It is found that the generated blast wave decays inversely proportional to the square of the distance from the fast-burning portion of the jet. The correlation is used to calculate the hazard distances by harm thresholds for five typical hydrogen applications. It is observed that in the case of a vehicle with onboard storage tank at pressure 70 MPa the “no-harm” distance for humans reduces from 10.5 m to 2.6 m when a thermally activated pressure relief device (TPRD) diameter decreases from 2 mm to a diameter of 0.5 mm.
Global Gas Report 2022
May 2022
Publication
This edition of the Global Gas Report covers two very turbulent years in the global gas industry and the wider global energy markets. The Covid-19 pandemic lockdowns with a brief period of excess supply and low prices gave way to tight energy markets extreme price volatility and a compounding geopolitical challenge to energy security. At the time of writing the ongoing Russia-Ukraine conflict has been affecting the flows of gas and has put Europe on a quest to diversify its energy and gas supply that is now opening a new paradigm in the energy industry. This report comes at a time when the situation for global commodity and gas markets is in a state of rapid change and the strategic path forwards for the gas industry and energy policy-makers is continually developing. One thing is clear this is a critical and decisive moment for the gas industry. How it navigates the way through this crisis and charts a path forward will shape its long-term success and the role that it will play in the energy transition and beyond. This is the moment for the gas industry to demonstrate that gas can deliver a sustainable and secure energy future for all and that natural gas and a portfolio of decarbonized low- and zero-carbon gases are key to an achievable energy transition. This year’s report assesses key gas market trends from 2020 and 2021 including Covid-19 outcomes tightness of supply price volatility investments and the upward reversal in the global emissions trend. It then turns to the main topic on the global energy agenda – security – and considers key variables impacting it from industry and policy perspectives as well as considering possible paths to reinforce it. Finally the report looks at the main decarbonization pathways for gas supply as they progressively develop to make gas itself a low or zero-carbon fuel for the future. This report seeks to deliver insights about the global gas sector and to inform its stakeholders partners and importantly global decision-makers about the state of play today and possibilities for the future. It concludes with key insights on how sustainability security and competitiveness can help to deliver a sustainable future in line with the goals of the Paris Agreement and the UN Sustainable Development Agenda.
Influence of Non-equilibrium Conditions on Liquid Hydrogen Storage Tank Behavior
Sep 2021
Publication
In a liquid hydrogen storage tank hydrogen vapor exists above the cryogenic liquid. A common modeling assumption of a liquid hydrogen tank is thermodynamic equilibrium. However this assumption may not hold in all conditions. A non-equilibrium storage tank with a pressure relief valve and a burst disc in parallel was modeled in this work. The model includes different boiling regimes to handle scenarios with high heat transfer. The model was first validated with a scenario where normal boil-off from an unused tank was compared to experimental data. Then four abnormal tank scenarios were explored: a loss of vacuum in the insulation layer a high ambient temperature (to simulate an engulfing fire) a high ambient temperature with a simultaneous loss of vacuum and high conduction through the insulation layer. The burst disc of the tank opened only in the cases with extreme heat transfer to the tank (i.e. fire with a loss of vacuum and high insulation conductivity) quickly releasing the hydrogen. In the cases with only a loss of vacuum or only external heat from fire the pressure relief valve on the tank managed to moderate the pressure below the burst disc activation pressure. The high insulation conductivity case highlights differences between the equilibrium and non-equilibrium tank models. The mass loss from the tank through the burst disc is slower using a non-equilibrium model because mass transfer from the liquid to gas phase within the tank becomes limiting. The implications of this model and how it can be used to help inform safety codes and standards are discussed.
CO2 Emissions Reduction through Increasing H2 Participation in Gaseous Combustible—Condensing Boilers Functional Response
Apr 2022
Publication
Considering the imperative reduction in CO2 emissions both from household heating and hot water producing facilities one of the mainstream directions is to reduce hydrocarbons in combustibles by replacing them with hydrogen. The authors analyze condensing boilers operating when hydrogen is mixed with standard gaseous fuel (CH4 ). The hydrogen (H2 ) volumetric participation in the mixture is considered to vary in the range of 0 to 20%. The operation of the condensing boilers will be numerically modeled by computational programs and prior validated by experimental studies concluded in a European Certified Laboratory. The study concluded that an increase in the combustible flow with 16% will compensate the maximum H2 concentration situation with no other implications on the boiler’s thermal efficiency together with a decrease in CO2 emissions by approximately 7%. By assuming 0.9 (to/year/boiler) the value of CO2 emissions reduction for the condensing boiler determined in the paper and extrapolating it for the estimated number of boilers to be sold for the period 2019–2024 a 254700-ton CO2/year reduction resulted.
Everything About Hydrogen Podcast: Masters of Scale: Mobilizing the Mobility Sector (Around Hydrogen Fuel Cells)
Nov 2020
Publication
We talk a lot on the EAH podcast series about where hydrogen fuel cell electric vehicles (FCEVs) fit into the overall zero emission vehicle (ZEV) ecosystem. From personal passenger vehicles and the family car to commercial trucking and public transportation fleets and everything in between. Different vehicles and different use cases call for different capabilities and that is what makes the future of decarbonized transportation co interesting.
The podcast can be found on their website
The podcast can be found on their website
Effect of Heat Transfer through the Release of Pipe on Simulations of Cryogenic Hydrogen Jet Fires and Hazard Distances
Sep 2021
Publication
Jet flames originated by cryo-compressed ignited hydrogen releases can cause life-threatening conditions in their surroundings. Validated models are needed to accurately predict thermal hazards from a jet fire. Numerical simulations of cryogenic hydrogen flow in the release pipe are performed to assess the effect of heat transfer through the pipe walls on jet parameters. Notional nozzle exit diameter is calculated based on the simulated real nozzle parameters and used in CFD simulations as a boundary condition to model jet fires. The CFD model was previously validated against experiments with vertical cryogenic hydrogen jet fires with release pressures up to 0.5 MPa (abs) release diameter 1.25 mm and temperatures as low as 50 K. This study validates the CFD model in a wider domain of experimental release conditions - horizontal cryogenic jets at exhaust pipe temperature 80 K pressure up to 2 MPa abs and release diameters up to 4 mm. Simulation results are compared against experimentally measured parameters as hydrogen mass flow rate flame length and radiative heat flux at several locations from the jet fire. The CFD model reproduces well experiments with reasonable engineering accuracy. Jet fire hazard distances established using three different criteria - temperature thermal radiation and thermal dose - are compared and discussed based on CFD simulation results.
A Numerical and Graphical Review of Energy Storage Technologies
Dec 2014
Publication
More effective energy production requires a greater penetration of storage technologies. This paper takes a looks at and compares the landscape of energy storage devices. Solutions across four categories of storage namely: mechanical chemical electromagnetic and thermal storage are compared on the basis of energy/power density specific energy/power efficiency lifespan cycle life self-discharge rates capital energy/power costs scale application technical maturity as well as environmental impact. It’s noted that virtually every storage technology is seeing improvements. This paper provides an overview of some of the problems with existing storage systems and identifies some key technologies that hold promise.
Potentials of Hydrogen Technologies for Sustainable Factory Systems
Mar 2021
Publication
The industrial sector is the world’s second largest emitter of greenhouse gases hence a methodology for decarbonizing factory systems is crucial for achieving global climate goals. Hydrogen is an important medium for the transition towards carbon neutral factories due to its broad applicability within the factory including its use in electricity and heat generation and as a process gas or fuel. One of the main challenges is the identification of economically and environmentally suitable design scenarios such as for the entire value chain for hydrogen generation and application. For example the infrastructure for renewable electricity hydrogen generation hydrogen conversion (e.g. into synthetic fuels) storage and transport systems as well as application in the factory. Due to the high volatility of energy generation and the related dynamic interdependencies within a factory system a valid technical economic and environmental evaluation of benefits induced by hydrogen technologies can only be achieved using digital factory models. In this paper we present a framework to integrate hydrogen technologies into factory systems. This enables decision makers to identify promising measures according to their expected impact and collect data for appropriate factory modelling. Furthermore a concept for factory modelling and simulation is presented and demonstrated in a case study from the electronics industry assessing the use of hydrogen for decentralized power and heat generation.
Investigation on the Changes of Pressure and Temperature in High Pressure Filling of Hydrogen Storage Tank
May 2022
Publication
Hydrogen as fuel has been considered as a feasible energy carry and which offers a clean and efficient alternative for transportation. During the high pressure filling the temperature in the hydrogen storage tank (HST) may rise rapidly due to the hydrogen compression. The high temperature may lead to safety problem. Thus for fast and safely refueling the hydrogen several key factors need to be considered. In the present study by the thermodynamics theories a mathematical model is established to simulate and analyze the high pressure filling process of the storage tank for the hydrogen station. In the analysis the physical parameters of normal hydrogen are introduced to make the simulation close to the actual process. By the numerical simulation for 50 MPa compressed hydrogen tank the temperature and pressure trends during filling are obtained. The simulation results for non-adiabatic filling were compared with the theoretically calculated ones for adiabatic conditions and the simulation results for non-adiabatic filling were compared with the simulation ones for adiabatic conditions. Then the influence of working pressure initial temperature mass flow rate initial pressure and inlet temperature on the temperature rise were analyzed. This study provides a theoretical research basis for high pressure hydrogen energy storage and hydrogenation technology.
Baselining the Body of Knowledge for Hydrogen Shock Interactions and Debris Escalation
Sep 2021
Publication
The differences in behaviour of hydrogen when compared to natural gas under deflagration and detonation scenarios are well known. The authors currently work in the area of fire and explosion analysis and have identified what they feel are potential gaps in the current Body of Knowledge (BOK) available to the sector. This is especially related to the behaviour around secondary shock formation and interactions with surrounding structures especially with ‘open’ structures such as steel frameworks typically seen in an offshore environment and practicable methods for determining debris formation and propagation. Whilst the defence sector has extensive knowledge in these areas this is primarily in the area of high explosives where the level of shocks observed is stronger than those resulting from a hydrogen detonation. This information would need to be reviewed and assessed to ensure it is appropriate for application in the hydrogen sector. Therefore with a focus on practicality the authors have undertaken a two-phase approach. The first phase involves carrying out a through literature search and discussions within our professional networks in order to ascertain whether there is a gap in the BOK. If good research guidance and tools to support this area of assessment already exist the authors have attempted to collate and consolidate this into a form that can be made more easily available to the community. Secondly if there is indeed a gap in the BOK the authors have attempted to ensure that all relevant information is collated to act as a reference and provide a consistent baseline for future research and development activities.
No more items...