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Simulation of the Inelastic Deformation of Porous Reservoirs Under Cyclic Loading Relevant for Underground Hydrogen Storage
Dec 2022
Publication
Subsurface geological formations can be utilized to safely store large-scale (TWh) renewable energy in the form of green gases such as hydrogen. Successful implementation of this technology involves estimating feasible storage sites including rigorous mechanical safety analyses. Geological formations are often highly heterogeneous and entail complex nonlinear inelastic rock deformation physics when utilized for cyclic energy storage. In this work we present a novel scalable computational framework to analyse the impact of nonlinear deformation of porous reservoirs under cyclic loading. The proposed methodology includes three diferent time-dependent nonlinear constitutive models to appropriately describe the behavior of sandstone shale rock and salt rock. These constitutive models are studied and benchmarked against both numerical and experimental results in the literature. An implicit time-integration scheme is developed to preserve the stability of the simulation. In order to ensure its scalability the numerical strategy adopts a multiscale fnite element formulation in which coarse scale systems with locally-computed basis functions are constructed and solved. Further the efect of heterogeneity on the results and estimation of deformation is analyzed. Lastly the Bergermeer test case—an active Dutch natural gas storage feld—is studied to investigate the infuence of inelastic deformation on the uplift caused by cyclic injection and production of gas. The present study shows acceptable subsidence predictions in this feld-scale test once the properties of the fnite element representative elementary volumes are tuned with the experimental data.
How Flexible Electricity Demand Stabilizes Wind and Solar Market Values: The Case of Hydrogen Electrolyzers
Nov 2021
Publication
Wind and solar energy are often expected to fall victim to their own success: the higher their share in electricity generation the more their revenue in electricity markets (their “market value”) declines. While market values may converge to zero in conventional power systems this study argues that “green” hydrogen production can effectively and permanently halt the decline by adding flexible electricity demand in low-price hours. To support this argument this article further develops the merit order model and uses price duration curves to include flexible hydrogen electrolysis and to derive an analytical formula for the minimum market value of renewables in the long-term market equilibrium. This hydrogen-induced minimum market value is quantified for a wide range of parameters using Monte Carlo simulations and complemented with results from a more detailed numerical electricity market model. It is shown that—due to flexible hydrogen production alone—market values across Europe will likely stabilize above €19 ± 9 MWh− 1 for solar energy and above €27 ± 8 MWh− 1 for wind energy in 2050 (annual mean estimate ± standard deviation). This is in the range of the projected levelized cost of renewables and other types of flexible electricity demand may further increase renewable market values. Market-based renewables may hence be within reach.
Assessment of Operability and Inspection, Maintenance and Repair Requirements for Transmission Pipelines and Installations in Hydrogen Service
Apr 2021
Publication
This report has been prepared for Hytechnical work programme to support the technical strategy for repurposing existing transmission pipelines and installations for the transportation and distribution of hydrogen and natural gas / hydrogen blends. The aim of the Hytechnical work programme is to support the implementation of the IGEM supplements to the standards TD/1 TD/13 TD/3 and TD/4.<br/>The report covers a desk study into the requirements for the inspection maintenance operation and repair of above 7 bar natural gas pipelines and installations designed and operated in accordance with the standards existing IGEM/TD/1 and IGEM/TD/13 which are repurposed for hydrogen service.
Everything About Hydrogen Podcast: Is Small the Perfect Answer for SMRs?
Jun 2020
Publication
On this week’s episode the team discuss the appeal of modular reforming of biogas and natural gas with Mo Vargas from Bayotech. The company use a proprietary modular reformer technology to help provide low cost decentralise hydrogen production units for onsite demand at various scales using biogas waste gases and natural gas with carbon capture. With large scale steam methane reforming accounting for 95% of hydrogen production in major markets like the US and Europe today the team dive into the good the bad and the unusual considerations behind the growing international demand for modular methane reforming technologies and how Bayotech see the transition from a CO2 intensive process today to a net zero emission future. All this and more on the show!
The podcast can be found on their website
The podcast can be found on their website
Techno-Economic Assessment of Green Hydrogen Production by an Off-Grid Photovoltaic Energy System
Jan 2023
Publication
Green hydrogen production is essential to meeting the conference of the parties’ (COP) decarbonization goals; however this method of producing hydrogen is not as cost-effective as hydrogen production from fossil fuels. This study analyses an off-grid photovoltaic energy system designed to feed a proton-exchange membrane water electrolyzer for hydrogen production to evaluate the optimal electrolyzer size. The system has been analyzed in Baghdad the capital of Iraq using experimental meteorological data. The 12 kWp photovoltaic array is positioned at the optimal annual tilt angle for the selected site. The temperature effect on photovoltaic modules is taken into consideration. Several electrolyzers with capacities in the range of 2–14 kW were investigated to assess the efficiency and effectiveness of the system. The simulation process was conducted using MATLAB and considering the project life span from 2021 to 2035. The results indicate that various potentially cost-competitive alternatives exist for systems with market combinations resembling renewable hydrogen wholesale. It has been found that the annual energy generated by the analyzed photovoltaic system is 18892 kWh at 4313 operating hours and the obtained hydrogen production cost ranges from USD 5.39/kg to USD 3.23/kg. The optimal electrolyzer capacity matches a 12 kWp PV system equal to 8 kW producing 37.5 kg/year/kWp of hydrogen for USD 3.23/kg.
Towards a Unified and Practical Industrial Model for Prediction of Hydrogen Embrittlement and Damage in Steels
Jul 2016
Publication
Bearing in mind the multiple effects of hydrogen in steels the specific mechanism of hydrogen embrittlement (HE) is active depending on the experimental conditions and numerous factors which can be grouped as environmental mechanical and material influences. A large number of contemporary studies and models about hydrogen environment assisted cracking and HE in steels are presented in the form of critical review in this paper. This critical review represent the necessary background for the development of a multiscale structural integrity model based on correlation between simultaneously active HE micro-mechanisms: the hydrogen-enhanced localized plasticity (HELP) and the hydrogen-enhanced decohesion (HEDE) - (HELP+HEDE) and macro-mechanical response of material unevenly enriched with hydrogen during service of boiler tubes in thermal fossil fuel power plant. Several different experimental methods and techniques were used to determine the boiler tube failure mechanism and afterwards also the viable HE mechanisms in the investigated ferritic-pearlitic low carbon steel grade 20 - St.20 (equivalent to AISI 1020). That represent a background for the development of a structural integrity model based on the correlation of material macro-mechanical properties to scanning electron microscopy fractography analysis of fracture surfaces of Charpy specimens in the presence of confirmed and simultaneously active HE micro-mechanisms (HELP+HEDE) in steel. The aim of this paper is to show how to implement what we have learned from theoretical HE models into the field to provide industry with valuable data and practical structural integrity model.
The Potential of Green Ammonia Production to Reduce Renewable Power Curtailment and Encourage the Energy Transition in China
Apr 2022
Publication
The pursuing of inter-regional power transmission to address renewable power curtailment in China has resulted in disappointing gains. This paper evaluates the case of local green ammonia production to address this issue. An improved optimization-based simulation model is applied to simulate lifetime green manufacturing and the impacts of main institutional incentives and oxygen synergy on investment are analysed. Levelized cost of ammonia is estimated at around 820 USD/t which is about twice the present price. The operating rate ammonia price the electrical efficiency of electrolysers and the electricity price are found to be the key factors in green ammonia investment. Carbon pricing and value-added tax exemption exert obvious influences on the energy transition in China. A subsidy of approximately 450 USD/t will be required according to the present price; however this can be reduced by 100 USD/t through oxygen synergy. Compared to inter-regional power transmission green ammonia production shows both economic and environmental advantages. Therefore we propose an appropriate combination of both options to address renewable power curtailment and the integration of oxygen manufacturing into hydrogen production. We consider the findings and policy implications will contribute to addressing renewable power curtailment and boosting the hydrogen economy in China.
Graphene Oxide @ Nickel Phosphate Nanocomposites for Photocatalytic Hydrogen Production
Mar 2021
Publication
The graphene oxide @nickel phosphate (GO:NPO) nanocomposites (NCs) are prepared by using a one-pot in-situ solar energy assisted method by varying GO:NPO ratio i.e. 0.00 0.25 0.50 0.75 1.00 1.25 1.50 and 2.00 without adding any surfactant or a structure-directing reagent. As produced GO:NPO nanosheets exhibited an improved photocatalytic activity due to the spatial seperation of charge carriers through interface where photoinduced electrons transferred from NiPO4 to the GO sheets without charge-recombination. Out of the series the system 1.00 GO:NPO NC show the optimum hydrogen production activity (15.37 μmol H2 h−1) towards water splitting under the visible light irradiation. The electronic environment of the nanocomposite GO-NiO6/NiO4-PO4 elucidated in the light of advance experimental analyses and theoretical DFT spin density calculations. Structural advanmcement of composites are well correlated with their hydrogen production activity.
Planning and Operational Aspects of Individual and Clustered Multi-Energy Microgrid Options
Feb 2022
Publication
With the restructuring of the power system household-level end users are becoming more prominent participants by integrating renewable energy sources and smart devices and becoming flexible prosumers. The use of microgrids is a way of aggregating local end users into a single entity and catering for the consumption needs of shareholders. Various microgrid architectures are the result of the local energy community following different decarbonisation strategies and are frequently not optimised in terms of size technology or other influential factors for energy systems. This paper discusses the operational and planning aspects of three different microgrid setups looking at them as individual market participants within a local electricity market. This kind of implementation enables mutual trade between microgrids without additional charges where they can provide flexibility and balance for one another. The developed models take into account multiple uncertainties arising from photovoltaic production day-ahead electricity prices and electricity load. A total number of nine case studies and sensitivity analyses are presented from daily operation to the annual planning perspective. The systematic study of different microgrid setups operational principles/goals and cooperation mechanisms provides a clear understanding of operational and planning benefits: the electrification strategy of decarbonising microgrids outperforms gas and hydrogen technologies by a significant margin. The value of coupling different types of multi-energy microgrids with the goal of joint market participation was not proven to be better on a yearly level compared to the operation of same technology-type microgrids. Additional analyses focus on introducing distribution and transmission fees to an MG cooperation model and allow us to come to the conclusion of there being a minor impact on the overall operation.
Influence of Carbon Catalysts on the Improvement of Hydrogen Storage Properties in a Body-Centered Cubic Solid Solution Alloy
Jun 2021
Publication
Body-centered cubic (BCC) alloys are considered as promising materials for hydrogen storage with high theoretical storage capacity (H/M ratio of 2). Nonetheless they often suffer from sluggish kinetics of hydrogen absorption and high hydrogen desorption temperature. Carbon materials are efficient hydrogenation catalysts however their influence on the hydrogen storage properties of BCC alloy has not been comprehensively studied. Therefore in this paper composites obtained by milling of carbon catalysts (carbon nanotubes mesoporous carbon carbon nanofibers diamond powder graphite fullerene) and BCC alloy (Ti1.5V0.5) were extensively studied in the non-hydrogenated and hydrogenated state. The structure and microstructure of the obtained materials were studied by scanning and transmission electron microscopes X-ray diffraction (XRD) and Raman spectroscopy. XRD and Raman measurements showed that BCC alloy and carbon structures were in most cases intact after the composite synthesis. The hydrogenation/dehydrogenation studies showed that all of the used carbon catalysts significantly improve the hydrogenation kinetics reduce the activation energy of the dehydrogenation process and decrease the dehydrogenation temperature (by nearly 100 K). The superior kinetic properties were measured for the composite with 5 wt % of fullerene that absorbs 3.3 wt % of hydrogen within 1 min at room temperature.
The Effect of Hydrogen Enrichment, Flame-flame Interaction, Confinement, and Asymmetry on the Acoustic Response of a Model Can Combustor
Apr 2022
Publication
To maximise power density practical gas turbine combustion systems have several injectors which can lead to complex interactions between flames. However our knowledge about the effect of flame-flame interactions on the flame response the essential element to predict the stability of a combustor is still limited. The present study investigates the effect of hydrogen enrichment flame-flame interaction confinement and asymmetries on the linear and non-linear acoustic response of three premixed flames in a simple can combustor. A parametric study of the linear response characterised by the flame transfer function (FTF) is performed for swirling and non-swirling flames. Flame-flame interactions were achieved by changing the injector spacing and the level of hydrogen enrichment by power from 10 to 50%. It was found that the latter had the most significant effect on the flame response. Asymmetry effects were investigated by changing one of the flames by using a different bluff-body to alter both the flame shape and flow field. The global flame response showed that the asymmetric cases can be reconstructed using a superposition of the two symmetric cases where all three bluff-bodies and flames are the same. Overall the linear response characterised by the flame transfer function (FTF) showed that the effect of increasing the level of hydrogen enrichment is more pronounced than the effect of the injector spacing. Increasing hydrogen enrichment results in more compact flames which minimises flame-flame interactions. More compact flames increase the cut-off frequency which can lead to self-excited modes at higher frequencies. Finally the non-linear response was characterised by measuring the flame describing function (FDF) at a frequency close to a self-excited mode of the combustor for different injector spacings and levels of hydrogen enrichment. It is shown that increasing the hydrogen enrichment leads to higher saturation amplitude whereas the effect of injector spacing has a comparably smaller effect.
Gas Goes Green: A System for All Seasons
Oct 2021
Publication
‘A System For All Seasons’ analyses Britain’s electricity generation and consumption trends concluding that the country’s wind and solar farms will have enough spare electricity generated in spring and summer when demand is lower to produce green hydrogen to the equivalent capacity of 25 Hinkley Point C nuclear power plants.
The hydrogen stored would provide the same amount of energy needed for every person in the UK to charge a Tesla Model S electric vehicle more than 21 times in the autumn and winter months when energy demand is highest creating a clean energy buffer that avoids having to manage limited energy supplies on the international markets.
Crucially the research finds that the UK has enough capacity to store the hydrogen in a combination of salt caverns and disused oil and gas fields in the North Sea as well other locations to meet this demand.
The research also finds that using renewable hydrogen will help reduce the total number of wind farms needed in 2050 by more than 75% because it will ensure electricity generated by Britain’s wind farms is used as efficiently as possible by avoiding surplus electricity going to waste.
‘A System For All Seasons’ finds that:
The hydrogen stored would provide the same amount of energy needed for every person in the UK to charge a Tesla Model S electric vehicle more than 21 times in the autumn and winter months when energy demand is highest creating a clean energy buffer that avoids having to manage limited energy supplies on the international markets.
Crucially the research finds that the UK has enough capacity to store the hydrogen in a combination of salt caverns and disused oil and gas fields in the North Sea as well other locations to meet this demand.
The research also finds that using renewable hydrogen will help reduce the total number of wind farms needed in 2050 by more than 75% because it will ensure electricity generated by Britain’s wind farms is used as efficiently as possible by avoiding surplus electricity going to waste.
‘A System For All Seasons’ finds that:
- Britain’s wind and solar farms could generate between 60-80GW of renewable hydrogen - the equivalent capacity of 25 Hinkley Point C nuclear power plants - from spare renewable electricity generated in the spring and summer months between May and October each year.
- Running the energy system this way will reduce the need for the total electricity generating capacity of UK wind farms from 500-600GW by 2050 down to 140-190GW – a reduction of up to 76%.
- It would mean Great Britain would be using spare renewable electricity that would otherwise go to waste to produce green hydrogen. Under the alternative scenario additional wind farms would need to be built to accommodate for autumn and wind energy demand peaks but be left unused during other times of the year.
- With 140-190GW of wind generation capacity 115 to 140TWh of green hydrogen would be stored – enough energy for every person in the UK to charge a Tesla Model S more than 21 times.
- The potential storage volume from Britain’s salt fields ranges from >1TWh up to 30TWh. For disused oil and gas fields the potential storage volume for individual sites ranges from ~1TWh up to 330TWh.
Aspects of Hydrogen and Biomethane Introduction in Natural Gas Infrastructure and Equipment
Aug 2021
Publication
The injection of green hydrogen and biomethane is currently seen as the next step towards the decarbonization of the gas sector in several countries. However the introduction of these gases in existent infrastructure has energetic material and operational implications that should be carefully looked at. With regard to a fully blown green gas grid transport and distribution will require adaptations. Furthermore the adequate performance of end-use equipment connected to the grid must be accounted for. In this paper a technical analysis of the energetic material and operational aspects of hydrogen and biomethane introduction in natural gas infrastructure is performed. Impacts on gas transmission and distribution are evaluated and an interchangeability analysis supported by one-dimensional Cantera simulations is conducted. Existing gas infrastructure seems to be generally fit for the introduction of hydrogen and biomethane. Hydrogen content up to 20% by volume appears to be possible to accommodate in current infrastructure with only minor technical modifications. However at the Distribution System Operator (DSO) level the introduction of gas quality tracking systems will be required due to the distributed injection nature of hydrogen and biomethane. The different tolerances for hydrogen blending of consumers depending on end-use equipment may be critical during the transition period to a 100% green gas grid as there is a risk of pushing consumers off the grid.
Van der Waals Heterostructures - Recent Progress in Electrode Materials for Clean Energy Applications
Jul 2021
Publication
The unique layered morphology of van der Waals (vdW) heterostructures give rise to a blended set of electrochemical properties from the 2D sheet components. Herein an overview of their potential in energy storage systems in place of precious metals is conducted. The most recent progress on vdW electrocatalysis covering the last three years of research is evaluated with an emphasis on their catalytic activity towards the oxygen reduction reaction (ORR) oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). This analysis is conducted in pair with the most active Pt-based commercial catalyst currently utilized in energy systems that rely on the above-listed electrochemistry (metal–air battery fuel cells and water electrolyzers). Based on current progress in HER catalysis that employs vdW materials several recommendations can be stated. First stacking of the two types vdW materials with one being graphene or its doped derivatives results in significantly improved HER activity. The second important recommendation is to take advantage of an electronic coupling when stacking 2D materials with the metallic surface. This significantly reduces the face-to-face contact resistance and thus improves the electron transfer from the metallic surface to the vdW catalytic plane. A dual advantage can be achieved from combining the vdW heterostructure with metals containing an excess of d electrons (e.g. gold). Despite these recent and promising discoveries more studies are needed to solve the complexity of the mechanism of HER reaction in particular with respect to the electron coupling effects (metal/vdW combinations). In addition more affordable synthetic pathways allowing for a well-controlled confined HER catalysis are emerging areas.
HyDeploy2: Appliance Testing Summary and Interpretation
Apr 2021
Publication
In order to inform the Quantified Risk Assessment (QRA) and procedures for the Winlaton trial the HyDeploy 2 project has undertaken a second programme of work focused on assessing the safe operation of gas appliances with hydrogen blended gas. This work extends the initial programme of work undertaken in HyDeploy 1 in 2018. Collectively these two projects provide an evidence base to support the project objective to demonstrate that there are no overarching safety concerns for the addition of up to 20 % mol/mol hydrogen to the GB natural gas distribution network.<br/>Click on the supplements tab to view the other documents from this report
Hydrogen Production in the Light of Sustainability: A Comparative Study on the Hydrogen Production Technologies Using the Sustainability Index Assessment Method
Sep 2021
Publication
Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies fossil fuels have been used in hydrogen production but due to several limitations especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods water or biomass materials are used as the raw material for hydrogen production. In this article after a brief review of different hydrogen production methods concerning the required raw material these methods are examined and ranked from different aspects of economic social environmental and energy and exergy analysis sustainability. In the following the current position of hydrogen production is discussed. Finally according to the introduced methods their advantages and disadvantages solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.
Comprehensive Performance Evaluation of Densified Liquid Hydrogen/Liquid Oxygen as Propulsion Fuel
Jan 2022
Publication
Densified liquid hydrogen/liquid oxygen is a promising propulsion fuel in the future. In order to systematically demonstrate the benefits and challenges of densified liquid hydrogen/liquid oxygen a transient thermodynamical model considering the heat leakage temperature rise engine thrust pressurization pressure of the tank and wall thickness of tank is developed in the present paper and the performance of densified liquid hydrogen/liquid oxygen as propulsion fuel is further evaluated in actual application. For liquid hydrogen/liquid oxygen tanks at different structural dimensions the effects of many factors such as temperature rise during propellant ground parking lift of engine thrust mass reduction of the tank structure and extension of spacecraft in‐orbit time are analyzed to demonstrate the comprehensive performance of liquid hydrogen/liquid oxygen after densification. Meanwhile the problem of subcooling combination matching of liquid hydro‐ gen/liquid oxygen is proposed for the first time. Combining the fuel consumption and engine thrust lifting the subcooling combination matching of liquid hydrogen/liquid oxygen at different mixing ratios and constant mixing ratios are discussed respectively. The results show that the relative engine thrust enhances by 6.96% compared with the normal boiling point state in the condition of slush hydrogen with 50% solid content and enough liquid oxygen. The in‐orbit time of spacecraft can extend about 2–6.5 days and 24–95 days for slush hydrogen with 50% solid content and liquid oxygen in the triple point state in different cryogenic tanks respectively. Due to temperature rise during parking the existing adiabatic storage scheme and filling scheme for densification LH2 need to be redesigned and for densification LO2 are suitable. It is found that there is an optimal subcooling matching relation after densification of liquid hydrogen/liquid oxygen as propulsion fuel. In other words the subcooling temperature of liquid hydrogen/liquid oxygen is not the lower the bet‐ ter but the matching relationship between LH2 subcooling degree and LO2 subcooling degree needs to be considered at the same time. It is necessary that the LO2 was cooled to 69.2 K and 54.5 K when the LH2 of 13.9 K and SH2 with 45% was adopted respectively. This research provides theoretical support for the promotion and application of densification cryogenic propellants.
Cost-optimal Reliable Power Generation in a Deep Decarbonisation Future
Jul 2019
Publication
Considering the targets of the Paris agreement rapid decarbonisation of the power system is needed. In order to study cost-optimal and reliable zero and negative carbon power systems a power system model of Western Europe for 2050 is developed. Realistic future technology costs demand levels and generator flexibility constraints are considered. The optimised portfolios are tested for both favourable and unfavourable future weather conditions using results from a global climate model accounting for the potential impacts of climate change on Europe’s weather. The cost optimal mix for zero or negative carbon power systems consists of firm low-carbon capacity intermittent renewable energy sources and flexibility capacity. In most scenarios the amount of low-carbon firm capacity is around 75% of peak load providing roughly 65% of the electricity demand. Furthermore it is found that with a high penetration of intermittent renewable energy sources a high dependence on cross border transmission batteries and a shift to new types of ancillary services is required to maintain a reliable power system. Despite relatively small changes in the total generation from intermittent renewable energy sources between favourable and unfavourable weather years of 6% emissions differ up to 70 MtCO2 yr−1 and variable systems costs up to 25%. In a highly interconnected power system with significant flexible capacity in the portfolio and minimal curtailment of intermittent renewables the potential role of green hydrogen as a means of electricity storage appears to be limited.
Improved Hydrogen Separation Performance of Asymmetric Oxygen Transport Membranes by Grooving in the Porous Support Layer
Nov 2020
Publication
Hydrogen separation through oxygen transport membranes (OTMs) has attracted much attention. Asymmetric membranes with thin dense layers provide low bulk diffusion resistances and high overall hydrogen separation performances. However the resistance in the porous support layer (PSL) limits the overall separation performance significantly. Engineering the structure of the PSL is an appropriate way to enable fast gas transport and increase the separation performance. There is no relevant research on studying the influence of the PSL on hydrogen separation performance so far. Herein we prepared Ce0.85Sm0.15O1.925 – Sm0.6Sr0.4Cr0.3Fe0.7O3-δ (SDC-SSCF) asymmetric membranes with straight grooves in PSL by tape-casting and laser grooving. A ~30% improvement in the hydrogen separation rate was achieved by grooving in the PSLs. It indicates that the grooves may reduce the concentration polarization resistance in PSL for the hydrogen separation process. This work provides a straight evidence on optimizing the structures of PSL for improving the hydrogen separation performance of the membrane reactors.
Research Progress of Cryogenic Materials for Storage and Transportation of Liquid Hydrogen
Jul 2021
Publication
Liquid hydrogen is the main fuel of large-scale low-temperature heavy-duty rockets and has become the key direction of energy development in China in recent years. As an important application carrier in the large-scale storage and transportation of liquid hydrogen liquid hydrogen cryogenic storage and transportation containers are the key equipment related to the national defense security of China’s aerospace and energy fields. Due to the low temperature of liquid hydrogen (20 K) special requirements have been put forward for the selection of materials for storage and transportation containers including the adaptability of materials in a liquid hydrogen environment hydrogen embrittlement characteristics mechanical properties and thermophysical properties of liquid hydrogen temperature which can all affect the safe and reliable design of storage and transportation containers. Therefore it is of great practical significance to systematically master the types and properties of cryogenic materials for the development of liquid hydrogen storage and transportation containers. With the wide application of liquid hydrogen in different occasions the requirements for storage and transportation container materials are not the same. In this paper the types and applications of cryogenic materials commonly used in liquid hydrogen storage and transportation containers are reviewed. The effects of low-temperature on the mechanical properties of different materials are introduced. The research progress of cryogenic materials and low-temperature performance data of materials is introduced. The shortcomings in the research and application of cryogenic materials for liquid hydrogen storage and transportation containers are summarized to provide guidance for the future development of container materials. Among them stainless steel is the most widely used cryogenic material for liquid hydrogen storage and transportation vessel but different grades of stainless steel also have different applications which usually need to be comprehensively considered in combination with its low temperature performance corrosion resistance welding performance and other aspects. However with the increasing demand for space liquid hydrogen storage and transportation the research on high specific strength cryogenic materials such as aluminum alloy titanium alloy or composite materials is also developing. Aluminum alloy liquid hydrogen storage and transportation containers are widely used in the space field while composite materials have significant advantages in being lightweight. Hydrogen permeation is the key bottleneck of composite storage and transportation containers. At present there are still many technical problems that have not been solved.
Operation of Metal Hydride Hydrogen Storage Systems for Hydrogen Compression Using Solar Thermal Energy
Mar 2016
Publication
By using a newly constructed bench-scale hydrogen energy system with renewable energy ‘Pure Hydrogen Energy System’ the present study demonstrates the operations of a metal hydride (MH) tank for hydrogen compression as implemented through the use solar thermal energy. Solar thermal energy is used to generate hot water as a heat source of the MH tank. Thus 70 kg of LaNi5 one of the most typical alloys used for hydrogen storage was placed in the MH tank. We present low and high hydrogen flow rate operations. Then the operations under winter conditions are discussed along with numerical simulations conducted from the thermal point of view. Results show that a large amount of heat (>100 MJ) is generated and the MH hydrogen compression is available.
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.
Morphological, Structural and Hydrogen Storage Properties of LaCrO3 Perovskite-Type Oxides
Feb 2022
Publication
Recently perovskite-type oxides have attracted researchers as new materials for solid hydrogen storage. This paper presents the performances of perovskite-type oxide LaCrO3 dedicated for hydrogen solid storage using both numerical and experimental methods. Ab initio calculations have been used here with the aim to investigate the electronic mechanical and elastic properties of LaCrO3Hx (x = 0 6) for hydrogen storage applications. Cell parameters crystal structures and mechanical properties are determined. Additionally the cohesive energy indicates the stability of the hydride. Furthermore the mechanical properties showed that both compounds (before and after hydrogenation) are stable. The microstructure and storage capacity at different temperatures of these compounds have been studied. We have shown that storage capacities are around 4 wt%. The properties obtained from this type of hydride showed that it can be used for future applications. XRD analysis was conducted in order to study the structural properties of the compound. Besides morphological thermogravimetric analysis was also conducted on the perovskite-type oxide. Finally a comparison of these materials with other hydrides used for hydrogen storage was carried out.
Liquid Organic Hydrogen Carriers - A Technology to Overcome Common Risks of Hydrogen Storage
Sep 2021
Publication
In transport and storage of hydrogen the risks are mainly seen in its volatile nature its ability to form explosive mixtures with air and the harsh conditions (high pressure or low temperature) for efficient storage. The concept of Liquid Organic Hydrogen Carriers (LOHC) offers a technology to overcome the above mentioned threats. The present submission describes the basics of the LOHC technology. It contains a comparison of a selection of common LOHC materials with a view on physical properties. The advantages of a low viscosity at low temperatures and a high flash point are expressed. LOHCs are also discussed as a concept to import large amounts of energy/hydrogen. A closer look is taken on the environmental and safety aspects of hydrogen storage in LOHCs since here the main differences to pressurized and cryo-storage of hydrogen can be found. The aim of this paper is to provide an overview of the principles of the LOHC technology the different LOHC materials and their risks and opportunities and an impression of a large scale scenario on the basis of the LOHC technology.
Application of Hydrogen and Hydrogen-containing Gases in Internal Combustion Engines
Nov 2019
Publication
The results of studies of the influence of hydrogen and hydrogen-containing gas additives on the parameters of various types of internal combustion engines are analyzed and summarized. It made possible to identify the features of the effect on the combustion of fuel during internal combustion engine operation at partial loads. The dependences of reducing the toxicity and fuel consumption of internal combustion engine on the amount of addition of hydrogen and a hydrogen-containing gas to the air-fuel mixture were obtained. It allowed to establish quantitative effects of free hydrogen in particular to quantify the region of small hydrogen additives and the conditions under which hydrogen exhibits the qualities of a chemically active component of the mixture.
CO2 Emissions Reduction Measures for RO-RO Vessels on Non-Profitable Coastal Liner Passenger Transport
Jun 2021
Publication
Reducing CO2 emissions from ships in unprofitable coastline transport using electricity and hydrogen has potential for island development to improve transport and protect biodiversity and nature. New technologies are a challenge for shipping companies and their introduction should be accompanied by a system of state aid for alternative energy sources. The energy requirements of an electric ferry for a route of up to 6 km were considered as well as the amount of hydrogen needed to generate the electricity required to charge the ferry batteries to enable a state aid scheme. For a daily ferry operation a specific fuel consumption of 60.6 g/kWh of liquid hydrogen is required in the system fuel cell with a total of 342.69 kg of hydrogen. Compared to marine diesel the use of electric ferries leads to a reduction of CO2 emissions by up to 90% including significantly lower NOx Sox and particulate matter (PM) emissions and operating costs by up to 80%.
Modeling and Economic Operation of Energy Hub Considering Energy Market Price and Demand
Feb 2022
Publication
This paper discusses the economic operation strategy of the energy hub which is being established in South Korea. The energy hub has five energy conversion devices: a turbo expander generator a normal fuel cell a fuel cell with a hydrogen outlet a small-scale combined heat and power device and a photovoltaic device. We are developing the most economically beneficial operation strategy for the operators who own the hub without making any systematic improvements to the energy market. First sixteen conversion efficiency matrices can be achieved by turning each device (except the PV) on or off. Next even the same energy must be divided into different energy flows according to price. The energy flow is controlled to obtain the maximum profit considering the internal load of the energy hub and the price fluctuations of the energy market. Using our operating strategy the return on investment period is approximately 9.9 years which is three years shorter than that without the operating strategy.
Implementation of Transition Metal Phosphides as Pt-Free Catalysts for PEM Water Electrolysis
Mar 2022
Publication
Proton Exchange Membrane (PEM) water electrolysis (WE) produces H2 with a high degree of purity requiring only water and energy. If the energy is provided from renewable energy sources it releases “Green H2” a CO2 -free H2 . PEMWE uses expensive and rare noble metal catalysts which hinder their use at a large industrial scale. In this work the electrocatalytic properties of Transition Metal Phosphides (TMP) catalysts supported on Carbon Black (CB) for Hydrogen Evolution Reaction (HER) were investigated as an alternative to Platinum Group Metals. The physico-chemical properties and catalytic performance of the synthesized catalysts were characterized. In the ex situ experiments the 25% FeP/CB 50% FeP/CB and 50% CoP/CB with overpotentials of −156.0 −165.9 and −158.5 mV for a current density of 100 mA cm−2 showed the best catalytic properties thereby progressing to the PEMWE tests. In those tests the 50% FeP/CB required an overpotential of 252 mV for a current density of 10 mA cm−2 quite close to the 220 mV of the Pt catalyst. This work provides a proper approach to the synthesis and characterization of TMP supported on carbon materials for the HER paving the way for further research in order to replace the currently used PGM in PEMWE.
Technology Roadmaps for Transition Management: The Case of Hydrogen Energy
Oct 2011
Publication
Technology roadmaps are increasingly used by governments to inform and promote technological transitions such as a transition to a hydrogen energy system. This paper develops a framework for understanding how current roadmapping practice relates to emerging theories of the governance of systems innovation. In applying this framework to a case study of hydrogen roadmaps the paper finds that roadmapping for transitions needs to place greater emphasis on ensuring good quality and transparent analytic and participatory procedures. To be most useful roadmaps should be embedded within institutional structures that enable the incorporation of learning and re-evaluation but in practice most transition roadmaps are one-off exercises
The Route from Green H2 Production through Bioethanol Reforming to CO2 Catalytic Conversion: A Review
Mar 2022
Publication
Currently a progressively different approach to the generation of power and the production of fuels for the automotive sector as well as for domestic applications is being taken. As a result research on the feasibility of applying renewable energy sources to the present energy scenario has been progressively growing aiming to reduce greenhouse gas emissions. Following more than one approach the integration of renewables mainly involves the utilization of biomass-derived raw material and the combination of power generated via clean sources with conventional power generation systems. The aim of this review article is to provide a satisfactory overview of the most recent progress in the catalysis of hydrogen production through sustainable reforming and CO2 utilization. In particular attention is focused on the route that starting from bioethanol reforming for H2 production leads to the use of the produced CO2 for different purposes and by means of different catalytic processes passing through the water–gas shift stage. The newest approaches reported in the literature are reviewed showing that it is possible to successfully produce “green” and sustainable hydrogen which can represent a power storage technology and its utilization is a strategy for the integration of renewables into the power generation scenario. Moreover this hydrogen may be used for CO2 catalytic conversion to hydrocarbons thus giving CO2 added value.
Climate Action: Prospects of Green Hydrogen in Africa
Feb 2022
Publication
Africa is rich with an abundance of renewable energy sources that can help meeting the continent’s demand for electricity to promote economic growth and meet global targets for CO2 reduction. Green Hydrogen is considered one of the most promising technologies for energy generation transportation and storage. In this paper the prospects of green hydrogen production potential in Africa are investigated along with its usage for future implementation. Moreover an overview of the benefits of shifting to green Hydrogen technology is presented. The current African infrastructure and policies are tested against future targets and goals. Furthermore the study embraces a detailed theoretical environmental technological and economic assessment putting the local energy demands into consideration.
Optimal Day-ahead Dispatch of an Alkaline Electrolyser System Concerning Thermal–electric Properties and State-transitional Dynamics
Oct 2021
Publication
Green hydrogen is viewed as a promising energy carrier for sustainable development goals. However it has suffered from high costs hindering its implementation. For a stakeholder who considers both renewable energy and electrolysis units it is important to exploit the flexibility of such portfolios to maximize system operational revenues. To this end an electrolyser model that can characterize its dynamic behavior is required in both electric and thermal aspects. In this paper we develop a comprehensive alkaline electrolyser model that is capable of describing its hydrogen production properties temperature variations and state transitions (among production stand-by and off states). This model is further used to study the optimal dispatch of an electrolyser based on a real-world hybrid wind/electrolyser system. The results show the model can effectively capture the coupling between thermal–electric dynamics and on–off performance of an electrolyser. The flexible operation strategy based on this model is proven to significantly increase daily revenues under different spot price conditions for electricity. Comparing the model with the ones derived from conventional modeling methods reveals this model offers more operating details and highlights several operational features such as the preference for working at partial load conditions although at the expense of more computing resources. It is suggested to use this model in studies related to energy integration operation planning and control scheme development in which the multi-domain dynamic properties of electrolysers in electricity/gas/heat need to be properly characterized. A sensitivity analysis on key parameters of such electrolyser system is also introduced to connect the daily operation with long-term planning.
Linking the Power and Transport Sectors—Part 2: Modelling a Sector Coupling Scenario for Germany
Jul 2017
Publication
“Linking the power and transport sectors—Part 1” describes the general principle of “sector coupling” (SC) develops a working definition intended of the concept to be of utility to the international scientific community contains a literature review that provides an overview of relevant scientific papers on this topic and conducts a rudimentary analysis of the linking of the power and transport sectors on a worldwide EU and German level. The aim of this follow-on paper is to outline an approach to the modelling of SC. Therefore a study of Germany as a case study was conducted. This study assumes a high share of renewable energy sources (RES) contributing to the grid and significant proportion of fuel cell vehicles (FCVs) in the year 2050 along with a dedicated hydrogen pipeline grid to meet hydrogen demand. To construct a model of this nature the model environment “METIS” (models for energy transformation and integration systems) we developed will be described in more detail in this paper. Within this framework a detailed model of the power and transport sector in Germany will be presented in this paper and the rationale behind its assumptions described. Furthermore an intensive result analysis for the power surplus utilization of electrolysis hydrogen pipeline and economic considerations has been conducted to show the potential outcomes of modelling SC. It is hoped that this will serve as a basis for researchers to apply this framework in future to models and analysis with an international focus.
Control of a Three-Phase Current Source Rectifier for H2 Storage Applications in AC Microgrids
Mar 2022
Publication
The share of electrical energy from renewable sources has increased considerably in recent years in an attempt to reduce greenhouse gas emissions. To mitigate the uncertainties of these sources and to balance energy production with consumption an energy storage system (ESS) based on water electrolysis to produce hydrogen is studied. It can be applied to AC microgrids where several renewable energy sources and several loads may be connected which is the focus of the study. When excess electricity production is converted into hydrogen via water electrolysis low DC voltages and high currents are applied which needs specific power converters. The use of a three-phase buck-type current source converter in a single conversion stage allows for an adjustable DC voltage to be obtained at the terminals of the electrolyzer from a three-phase AC microgrid. The voltage control is preferred to the current control in order to improve the durability of the system. The classical control of the buck-type rectifier is generally done using two loops that correspond only to the control of its output variables. The lack of control of the input variables may generate oscillations of the grid current. Our contribution in this article is to propose a new control for the buck-type rectifier that controls both the input and output variables of the converter to avoid these grid current oscillations without the use of active damping methods. The suggested control method is based on an approach using the flatness properties of differential systems: it ensures the large-signal stability of the converter. The proposed control shows better results than the classical control especially in oscillation mitigation and dynamic performances with respect to the rejection of disturbances caused by a load step.
Life Cycle Greenhouse Gas Emissions of Alternative Fuels and Powertrains for Medium-duty Trucks: A Singapore Case Study
Mar 2022
Publication
Alternatives to conventional diesel engines in medium/heavy-duty commercial trucks offer promising solutions to decarbonize road freight. We compare the life cycle greenhouse gas (GHG) emissions from diesel battery electric (BEV) and hydrogen fuel cell (FCV) medium-duty urban delivery trucks (gross vehicle weight 3.5 – 7 metric tonnes) in Singapore including the vehicle and fuel production use phase and end-of-life stages. Use phase energy demand was estimated by simulating energy consumption on local real-world driving cycles. BEVs powered by the 2019 electricity mix had up to 11% lower GHG emissions than conventional diesel but doubling battery capacity to meet travel range requirements resulted in up to 12% higher emissions. FCVs using gaseous hydrogen via steam methane reforming achieved 23 – 30% GHG reductions while satisfying range requirements. Efforts in obtaining updated and reliable data on vehicle production remain critical for assessments of emerging technologies and enacting evidence-based policies to decarbonize road freight.
Experimental Investigation of the Effect of Hydrogen Addition on Combustion Performance and Emissions Characteristics of a Spark Ignition High Speed Gasoline Engine
Sep 2014
Publication
Considering energy crises and pollution problems today much work has been done for alternative fuels for fossil fuels and lowering the toxic components in the combustion products. Expert studies proved that hydrogen one of the prominent alternative energy source which has many excellent combustion properties that can be used for improving combustion and emissions performance of gasoline-fuelled spark ignition (SI) engines. This article experimentally investigated the performance and emission characteristics of a high speed single cylinder SI engine operating with different hydrogen gasoline blends. For this purpose the conventional carburetted high speed SI engine was modified into an electronically controllable engine with help of electronic control unit (ECU) which dedicatedly used to control the injection timings and injection durations of gasoline. Various hydrogen enrichment levels were selected to investigate the effect of hydrogen addition on engine brake mean effective pressure (Bmep) brake thermal efficiency volumetric efficiency and emission characteristics. The test results demonstrated that combustion performances fuel consumption and brake mean effective pressure were eased with hydrogen enrichment. The experimental results also showed that the brake thermal efficiency was higher than that for the pure gasoline operation. Moreover HC and CO emissions were all reduced after hydrogen enrichment.
Two Generations of Hydrogen Powertrain—An Analysis of the Operational Indicators in Real Driving Conditions (RDC)
Jun 2022
Publication
Hydrogen fuel cells are systems that can be successfully used to partially replace internal combustion propulsion systems. For this reason the article presents an operational analysis of energy flow along with an analysis of individual energy transmission systems. Two generations of the Toyota Mirai vehicle were used for the tests. The operational analyses were carried out on the same route (compliant with RDE test requirements) assessing the system’s operation in three driving sections (urban rural and motorway). Both generations of the drive system with fuel cells are quite different which affects the obtained individual systems operation results as well as the overall energy flow. Research was carried out on the energy flow in the fuel cells FC converter battery and electric motor using a dedicated data acquisition system. The analyses were carried out in relation to the energy of fuel cells battery energy and recovered braking energy. It was found that in the urban drive section of the second-generation system (due to its much larger mass) a slightly higher energy consumption value was obtained (by about 2%). However in the remaining phases of the test consumption was lower (the maximum difference was 18% in the rural phase). Total energy consumption in the research test was 19.64 kWh/100 km for the first-generation system compared to 18.53 kWh/100 km for the second-generation system. Taking into account the increased mass of the second-generation vehicle resulted in significantly greater benefits in the second-generation drive (up to 37% in individual drive sections and about 28% in the entire drive test).
Everything About Hydrogen Podcast: The year-end Round Up! 2020 in Review
Dec 2020
Publication
2020 has been a year for the history books! Some good most of it not so good; but 2020 has been a boom year for the future of hydrogen technologies. Patrick Chris and Andrew do their level best on this episode to talk about all the stories and the highlights of 2020 in under 50 minutes. Have a listen and let us know if we missed anything in our penultimate episode of 2020!
The podcast can be found on their website
The podcast can be found on their website
CFD Modeling on Natural and Forced Ventilation During Hydrogen Leaks in a Pressure Regulator Process of a Residential Area
Mar 2022
Publication
Hydrogen fuel cells have been installed in more than 100 facilities and numerous homes in Ulsan hydrogen town in the Republic of Korea. Despite the advantages of hydrogen accidents can still occur near residential areas. Thus appropriate risk mitigation plans should be established. In this study a computational fluid dynamics (CFD) model of natural and forced ventilation is presented as an emergency response to hydrogen leakages in pressure regulator equipment housing. The CFD model is developed and investigated using three vent configurations: UP CROSS and UP-DOWN. The simulation results indicate that the UPDOWN configuration achieves the lowest internal hydrogen concentration out of the three. In addition the relationship between the total vent size and internal hydrogen concentration is determined. A vent size of 12% of the floor area has the lowest hydrogen concentration. The use of nitrogen for forced ventilation during emergencies is proposed to ensure that the hydrogen concentration of the released gas is less than one-fourth of the lower flammability 2 / 25 limit of hydrogen. Compared to natural ventilation the time required to reach safe conditions is decreased when nitrogen forced ventilation is used.
Proton Exchange Membrane Hydrogen Fuel Cell as the Grid Connected Power Generator
Dec 2020
Publication
In this paper a proton exchange membrane fuel cell (PEMFC) is implemented as a grid-connected electrical generator that uses hydrogen gas as fuel and air as an oxidant to produce electricity through electrochemical reactions. Analysis demonstrated that the performance of the PEMFC greatly depends on the rate of fuel supply and air supply pressure. Critical fuel and air supply pressures of the PEMFC are analysed to test its feasibility for the grid connection. Air and fuel supply pressures are varied to observe the effects on the PEMFC characteristics efficiency fuel supply and air consumption over time. The PEMFC model is then implemented into an electrical power system with the aid of power electronics applications. Detailed mathematical modelling of the PEMFC is discussed with justification. The PEMFC functions as an electrical generator that is connected to the local grid through a power converter and a transformer. Modulation of the converter is controlled by means of a proportional-integral controller. The two-axis control methodology is applied to the current control of the system. The output voltage waveform and control actions of the controller on the current and frequency of the proposed system are plotted as well. Simulation results show that the PEMFC performs efficiently under certain air and fuel pressures and it can effectively supply electrical power to the grid.
Hydrogen Production Possibilities in Slovak Republic
Mar 2022
Publication
Slovak Republic is a member of the European Union and is a part of the European energy market. Although Slovakia contributes only marginally to global emissions there is an effort to meet obligations from the Paris climate agreement to reduce greenhouse gases. As in many countries power industry emissions dominate Slovakia’s emissions output but are partly affected and lowered by the share of nuclear energy. The transition from fossil fuels to renewables is supported by the government and practical steps have been taken to promote the wide use of renewable resources such as biomass or solar energy. Another step in this transition process is the support of new technologies that use hydrogen as the primary energy source. The European Union widely supports this effort and is looking for possible sources for hydrogen generation. One of the main renewable resources is hydropower which is already used in the Slovak Republic. This article presents the current situation of the energy market in Slovakia and possible developments for future hydrogen generation.
A Review of Projected Power-to-Gas Deployment Scenarios
Jul 2018
Publication
Technical economic and environmental assessments of projected power-to-gas (PtG) deployment scenarios at distributed- to national-scale are reviewed as well as their extensions to nuclear-assisted renewable hydrogen. Their collective research trends outcomes challenges and limitations are highlighted leading to suggested future work areas. These studies have focused on the conversion of excess wind and solar photovoltaic electricity in European-based energy systems using low-temperature electrolysis technologies. Synthetic natural gas either solely or with hydrogen has been the most frequent PtG product. However the spectrum of possible deployment scenarios has been incompletely explored to date in terms of geographical/sectorial application environment electricity generation technology and PtG processes products and their end-uses to meet a given energy system demand portfolio. Suggested areas of focus include PtG deployment scenarios: (i) incorporating concentrated solar- and/or hybrid renewable generation technologies; (ii) for energy systems facing high cooling and/or water desalination/treatment demands; (iii) employing high-temperature and/or hybrid hydrogen production processes; and (iv) involving PtG material/energy integrations with other installations/sectors. In terms of PtG deployment simulation suggested areas include the use of dynamic and load/utilization factor-dependent performance characteristics dynamic commodity prices more systematic comparisons between power-to-what potential deployment options and between product end-uses more holistic performance criteria and formal optimizations.
Electric-field-promoted Photo-electrochemical Production of Hydrogen from Water Splitting
Jul 2021
Publication
Given that conversion efficiencies of incident solar radiation to liquid fuels e.g. H2 are of the order of a few percent or less as quantified by ‘solar to hydrogen’ (STH) economically inexpensive and operationally straightforward ways to boost photo-electrochemcial (PEC) H2 production from solar-driven water splitting are important. In this work externally-applied static electric fields have led to enhanced H2 production in an energy-efficient manner with up to ~30–40% increase in H2 (bearing in mind fieldinput energy) in a prototype open-type solar cell featuring rutile/titania and hematite/iron-oxide (Fe2O3) respectively in contact with an alkaline aqueous medium (corresponding to respective relative increases of STH by ~12 and 16%). We have also performed non-equilibrium ab-initio molecular dynamics in both static electric and electromagnetic (e/m) fields for water in contact with a hematite/iron-oxide (0 0 1) surface observing enhanced break-up of water molecules by up to ~70% in the linear-response régime. We discuss the microscopic origin of such enhanced water-splitting based on experimental and simulation-based insights. In particular we external-field direction at the hematite surfaces and scrutinise properties of the adsorbed water molecules and OH– and H3O+ species e.g. hydrogen bonds between water-protons and the hematite surfaces’ bridging oxygen atoms as well as interactions between oxygen atoms in adsorbed water molecules and underlying iron atoms.
Challenges and Prospects of Renewable Hydrogen-based Strategies for Full Decarbonization of Stationary Power Applications
Oct 2021
Publication
The exponentially growing contribution of renewable energy sources in the electricity mix requires large systems for energy storage to tackle resources intermittency. In this context the technologies for hydrogen production offer a clean and versatile alternative to boost renewables penetration and energy security. Hydrogen production as a strategy for the decarbonization of the energy sources mix has been investigated since the beginning of the 1990s. The stationary sector i.e. all parts of the economy excluding the transportation sector accounts for almost three-quarters of greenhouse gases (GHG) emissions (mass of CO2-eq) in the world associated with power generation. While several publications focus on the hybridization of renewables with traditional energy storage systems or in different pathways of hydrogen use (mainly power-to-gas) this study provides an insightful analysis of the state of art and evolution of renewable hydrogen-based systems (RHS) to power the stationary sector. The analysis started with a thorough review of RHS deployments for power-to-power stationary applications such as in power generation industry residence commercial building and critical infrastructure. Then a detailed evaluation of relevant techno-economic parameters such as levelized cost of energy (LCOE) hydrogen roundtrip efficiency (HRE) loss of power supply probability (LPSP) self-sufficiency ratio (SSR) or renewable fraction (fRES) is provided. Subsequently lab-scale plants and pilot projects together with current market trends and commercial uptake of RHS and fuel cell systems are examined. Finally the future techno-economic barriers and challenges for short and medium-term deployment of RHS are identified and discussed.
Thermochemical Recuperation to Enable Efficient Ammonia-Diesel Dual-Fuel Combustion in a Compression Ignition Engine
Nov 2021
Publication
A thermochemical recuperation (TCR) reactor was developed and experimentally evaluated with the objective to improve dual-fuel diesel–ammonia compression ignition engines. The novel system simultaneously decomposed ammonia into a hydrogen-containing mixture to allow high diesel fuel replacement ratios and oxidized unburned ammonia emissions in the exhaust overcoming two key shortcomings of ammonia combustion in engines from the previous literature. In the experimental work a multi-cylinder compression ignition engine was operated in dual-fuel mode using intake-fumigated ammonia and hydrogen mixtures as the secondary fuel. A full-scale catalytic TCR reactor was constructed and generated the fuel used in the engine experiments. The results show that up to 55% of the total fuel energy was provided by ammonia on a lower heating value basis. Overall engine brake thermal efficiency increased for modes with a high exhaust temperature where ammonia decomposition conversion in the TCR reactor was high but decreased for all other modes due to poor combustion efficiency. Hydrocarbon and soot emissions were shown to increase with the replacement ratio for all modes due to lower combustion temperatures and in-cylinder oxidation processes in the late part of heat release. Engine-out oxides of nitrogen (NOx) emissions decreased with increasing diesel replacement levels for all engine modes. A higher concentration of unburned ammonia was measured in the exhaust with increasing replacement ratios. This unburned ammonia predominantly oxidized to NOx species over the oxidation catalyst used within the TCR reactor. Ammonia substitution thus increased post-TCR reactor ammonia and NOx emissions in this work. The results show however that engine-out NH3 -to-NOx ratios were suitable for passive selective catalytic reduction thus demonstrating that both ammonia and NOx from the engine could be readily converted to N2 if the appropriate catalyst were used in the TCR reactor.
Risk Assessment and Mitigation Evaluation for Hydrogen Vehicles in Private Garages. Experiments and Modelling
Sep 2021
Publication
Governments and local authorities introduce new incentives and regulations for cleaner mobility as part of their environmental strategies to address energy challenges. Fuel cell electric vehicles (FCEVs) are becoming increasingly important and will extend beyond captive fleets reaching private users. Research on hydrogen safety issues is currently led in several projects in order to highlight and manage risks of FCEVs in confined spaces such as tunnels underground parkings repair garages etc. But what about private garages - that involve specific geometries volumes congestion ventilation? This study has been carried out in the framework of PRHyVATE JIP project which aims at better understanding hydrogen build-up and distribution in a private garage. The investigation went through different rates and modes of ventilation. As first step an HAZID (Hazard Identification) has been realized for a generic FCEV. This preliminary work allowed to select and prioritize accidental release scenarios to be explored experimentally with helium in a 40-m3 garage. Several configurations of release ventilation modes and congestion – in transient regime and at steady state – have been tested. Then analytical and numerical calculation approaches have been applied and adjusted to develop a simplified methodology. This methodology takes into account natural ventilation for assessment of hydrogen accumulation and mitigation means optimization. Finally a global risk evaluation – including ignition of a flammable hydrogen-air mixture – has been performed to account for the mostly feared events and to evaluate their consequences in a private garage. Thus preliminary recommendations good practices and safety features for safely parking FCEVs in private garages can be proposed.
Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus
May 2018
Publication
The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a “hydrogen city” model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production hydrogen storage and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80 which is above the value of conventional district energy systems and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 ◦C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.
Three-dimensional Simulations of Lean H2-air Flames Propagating in a Narrow Gap: n the Validity of the Quasi-two-dimensional Appoximation
Sep 2021
Publication
The premixed propagation of lean isobaric H2-air flames (φ = 0.3) in Hele-Shaw cells (i.e. two parallel plates separated by a small distance h on the order of the thickness of the planar adiabatic flame δf ∼ 3 mm) is investigated numerically. Three-dimensional (3D) simulations with detailed chemistry and transport are used to examine the effect of h on the flame dynamics and its overall normalized propagation speed (S T /S L) for a semi-closed system of size 25δf × 25δf × h. To determine the validity of an existing quasi-two-dimensional (quasi-2D) formulation (derived in the limit of h → 0) to capture the 3D dynamics results for h = 0.1δf h = 0.5δf and h = δf are reported. For h = 0.1δf strong cell splitting/merging is observed with associated low frequency/high amplitude oscillations in the temporal evolution of S T /S L (10-17Hz; 6 ≤ S T /S L ≤ 10). Larger values of h exhibit a much smoother evolution. For h = 0.5δf the cell splitting/merging is milder relaxing to a steady propagating speed of S T /S L ∼ 6 after an initial transient; for h = 1δf the flame dynamics along the h direction starts to play an important role showing two distinct phases: (i) initial symmetric propagation with a linear increase in S T /S L (from 5.3 to 6.8) as early signs of asymmetry are visible (ii) followed by a fully non-symmetric propagation resulting in an abrupt increase in S T /S L that quickly relaxes to a constant value thereafter (S T /S L ∼ 10). Our preliminary results suggest that for the lean H2-air mixture considered the quasi-2D approximation breaks down for h > 0.1δf .
Design and Performance Assessment of a Solar-to-hydrogen System Thermally Assisted by Recovered Heat from a Molten Carbonate Fuel Cell
Mar 2022
Publication
Solar-to-hydrogen plants are predominantly based on steam electrolysis. Steam electrolysis requires water electricity and heat. The excess electric energy is generally converted into hydrogen via an electrolyser. The use of waste heat in hydrogen generation process promises energy efficiency improvement and production fluctuation reductions. This work investigates the techno-economic performance of the proposed system which recovers the waste heat from molten carbonate fuel cell and uses solar energy to produce steam. Comparison of thermally assisted solar system with corresponding solar system is done. The fuel cell provides 80% of the required thermal energy. The solar PV array provides the required electricity. The thermally assisted solar-to-hydrogen system annual energy efficiency (38.5 %) is higher than that of solar- to- hydrogen system. The investment cost of the proposed system is 2.4 % higher than that using only solar parabolic trough collector for the same required amount of heat. The advantage is that the fuel cell simultaneously produces electricity and heat. The recovery of waste heat allows getting an annual overall efficiency of 63.2 % for the molten carbonate fuel cell. It yields 2152 MWh of electricity per year. The 1 MW electrolysers annually generates 74 tonnes of hydrogen.
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.
Numerical Study of the Effects of Tunnel Inclination and Ventilation on the Dispersion of Hydrogen Released from a Car
Sep 2021
Publication
Hydrogen cars are expected to play an important role in a decarbonised clean-transport future. Safety issues arise though in tunnels due to the possibility of accidental release and accumulation of hydrogen. This Computational Fluid Dynamics (CFD) study focuses on the effect of tunnel inclination and ventilation on hydrogen dispersion. A horseshoe shaped tunnel of 200 m length is considered in all seventeen cases examined. In most cases hydrogen is released from the bottom of a car placed at the center of the tunnel. Various inclinations in-tunnel wind speeds and fuel tank Pressure Relief Device (PRD) diameters were considered in order to assess their influence on safety. It was found that even if the long-term influence of the inclination is positive there is no systematic effect at initial stages nor at the most dangerous ‘nearly-stoichiometric’ cloud volumes (25% - 35% v/v). Adverse effects may also exist like the occasionally higher flammable cloud (4% - 75% v/v). Regarding ventilation it was found that even low wind speeds (e.g. 1 m/s) can reduce the flammable cloud by several times. However no significant effect on the total nearly-stoichiometric volumes was found for most of the cases examined. Ventilation can also cause adverse effects as for example at mid-term of the release duration in some cases. Concerning the PRD diameter a reduction from 4 mm to 2 mm resulted in about five times smaller maximum of the nearly-stoichiometric cloud volume. In addition the effect of release orientation on hydrogen cloud was examined and it was found that the downwards direction presents drawbacks compared to the backwards and upwards release directions.
Import Options for Chemical Energy Carriers from Renewable Sources to Germany
Feb 2024
Publication
Import and export of fossil energy carriers are cornerstones of energy systems world-wide. If energy systems are to become climate neutral and sustainable fossil carriers need to be substituted with carbon neutral alternatives or electrified if possible. We investigate synthetic chemical energy carriers hydrogen methane methanol ammonia and Fischer-Tropsch fuels produced using electricity from Renewable Energy Source (RES) as fossil substitutes. RES potentials are obtained from GIS-analysis and hourly resolved time-series are derived using reanalysis weather data. We model the sourcing of feedstock chemicals synthesis and transport along nine different Energy Supply Chains to Germany and compare import options for seven locations around the world against each other and with domestically sourced alternatives on the basis of their respective cost per unit of hydrogen and energy delivered. We find that for each type of chemical energy carrier there is an import option with lower costs compared to domestic production in Germany. No single exporting country or energy carrier has a unique cost advantage since for each energy carrier and country there are cost-competitive alternatives. This allows exporter and infrastructure decisions to be made based on other criteria than energy and cost. The lowest cost means for importing of energy and hydrogen are by hydrogen pipeline from Denmark Spain and Western Asia and Northern Africa starting at 36 EUR/MWhLHV to 42 EUR/MWhLHV or 1.0 EUR/kgH2 to 1.3 EUR/kgH2 (in 2050 assuming 5% p.a. capital cost). For complex energy carriers derived from hydrogen like methane ammonia methanol or Fischer-Tropsch fuels imports from Argentina by ship to Germany are lower cost than closer exporters in the European Union or Western Asia and Northern Africa. For meeting hydrogen demand direct hydrogen imports are more attractive than indirect routes using methane methanol or ammonia imports and subsequent decomposition to hydrogen because of high capital investment costs and energetic losses of the indirect routes. We make our model and data available under open licenses for adaptation and reuse.
Hy4Heat Annex To Site Specific Safety Case for Hydrogen Community Demonstration - Work Package 7
May 2021
Publication
The Hy4Heat Safety Assessment has focused on assessing the safe use of hydrogen gas in certain types of domestic properties and buildings. The summary reports (the Precis and the Safety Assessment Conclusions Report) bring together all the findings of the work and should be looked to for context by all readers. The technical reports should be read in conjunction with the summary reports. While the summary reports are made as accessible as possible for general readers the technical reports may be most accessible for readers with a degree of technical subject matter understanding. All of the safety assessment reports have now been reviewed by the HSE<br/>Annex prepared to support Site Specific Safety Cases for hydrogen gas community demonstrations based on work undertaken by the Hy4Heat programme. It covers a collection of recommended risk reduction measures for application downstream of the Emergency Control Valve (ECV)
Publication Handbook for Hydrogen Fuelled Vessels
Jun 2021
Publication
Green hydrogen could play a crucial role in the maritime industry’s journey towards decarbonization. Produced through electrolysis hydrogen is emission free and could be widely available across the globe in future – as a marine fuel or a key enabler for synthetic fuels. Many in shipping recognize hydrogen’s potential as a fuel but the barriers to realizing this potential are substantial.<br/>The 1st Edition of the ‘Handbook for Hydrogen-fuelled Vessels’ offers a road map towards safe hydrogen operations using fuel cells. It details how to navigate the complex requirements for design and construction and it covers the most important aspects of hydrogen operations such as safety and risk mitigation engineering details for hydrogen systems and implementation phases for maritime applications based on the current regulatory Alternative Design process framework.<br/>This publication is the result of the 1st phase of the DNV-led Joint Industry Project MarHySafe which has brought together a consortium of 26 leading company and associations. The project is ongoing and this publication will be continually updated to reflect the latest industry expertise on hydrogen as ship fuel.
Potential and Challenges of Low-carbon Energy Options: Comparative Assessment of Alternative Fuels for the Transport Sector
Dec 2018
Publication
The deployment of low-emission alternative fuels is crucial to decarbonise the transport sector. A number of alternatives like hydrogen or dimethyl ether/methanol synthesised using CO2 as feedstock for fuel production (hereafter refer to “CO2-based fuels”) have been proposed to combat climate change. However the decarbonisation potential of CO2-based fuels is under debate because CO2 is re-emitted to the atmosphere when the fuel is combusted; and the majority of hydrogen still relies on fossil resources which makes its prospects of being a low-carbon fuel dependent on its manufacturing process. First this paper investigates the relative economic and environmental performance of hydrogen (produced from conventional steam methane reforming and produced via electrolysis using renewable energy) and CO2- based fuels (dimethyl ether and methanol) considering the full carbon cycle. The results reveal that hydrogen produced from steam methane reforming is the most economical option and that hydrogen produced via electrolysis using renewables has the best environmental profile. Whereas the idea of CO2-based fuels has recently gained much interest it has for the foreseeable future rather limited practical relevance since there is no favourable combination of cost and environmental performance. This will only change in the long run and requires that CO2 is of non-fossil origin i.e. from biomass combustion or captured from air. Second this paper address unresolved methodological issues in the assessment of CO2-based fuels such as the possible allocation of emissions to the different sectors involved. The outcomes indicate that implementing different allocation approaches substantially influences the carbon footprint of CO2-based fuels. To avoid allocation issues expanding the boundaries including the entire system and is therefore recommended.
Converting Sewage Water into H2 Fuel Gas Using Cu/CuO Nanoporous Photocatalytic Electrodes
Feb 2022
Publication
This work reports on H2 fuel generation from sewage water using Cu/CuO nanoporous (NP) electrodes. This is a novel concept for converting contaminated water into H2 fuel. The preparation of Cu/CuO NP was achieved using a simple thermal combustion process of Cu metallic foil at 550 ◦C for 1 h. The Cu/CuO surface consists of island-like structures with an inter-distance of 100 nm. Each island has a highly porous surface with a pore diameter of about 250 nm. X-ray diffraction (XRD) confirmed the formation of monoclinic Cu/CuO NP material with a crystallite size of 89 nm. The prepared Cu/CuO photoelectrode was applied for H2 generation from sewage water achieving an incident to photon conversion efficiency (IPCE) of 14.6%. Further the effects of light intensity and wavelength on the photoelectrode performance were assessed. The current density (Jph) value increased from 2.17 to 4.7 mA·cm−2 upon raising the light power density from 50 to 100 mW·cm−2 . Moreover the enthalpy (∆H*) and entropy (∆S*) values of Cu/CuO electrode were determined as 9.519 KJ mol−1 and 180.4 JK−1 ·mol−1 respectively. The results obtained in the present study are very promising for solving the problem of energy in far regions by converting sewage water to H2 fuel.
Nuclear-Renewables Energy System for Hydrogen and Electricity Production
May 2011
Publication
In the future the world may have large stranded resources of low-cost wind and solar electricity. Renewable electricity production does not match demand and production is far from major cities. The coupling of nuclear energy with renewables may enable full utilization of nuclear and renewable facilities to meet local electricity demands and export pipeline hydrogen for liquid fuels fertilizer and metals production. Renewables would produce electricity at full capacity in large quantities. The base-load nuclear plants would match electricity production with demand by varying the steam used for electricity versus hydrogen production. High-temperature electrolysis (HTE) would produce hydrogen from water using (a) steam from nuclear plants and (b) electricity from nuclear plants and renewables. During times of peak electricity demand the HTE cells would operate in reverse fuel cell mode to produce power substituting for gas turbines that are used for very few hours per year and that thus have very high electricity costs. The important net hydrogen production would be shipped by pipeline to customers. Local hydrogen storage would enable full utilization of long-distance pipeline capacity with variable production. The electricity and hydrogen production were simulated with real load and wind data to understand under what conditions such systems are economic. The parametric case study uses a wind-nuclear system in North Dakota with hydrogen exported to the Chicago refinery market. North Dakota has some of the best wind conditions in the United States and thus potentially low-cost wind. The methodology allows assessments with different economic and technical assumptions - including what electrolyzer characteristics are most important for economic viability.
Extreme Energetic Materials at Ultrahigh Pressures
Jul 2020
Publication
Owing to their extremely high energy density single-bonded polymeric nitrogen and atomic metallic hydrogen are generally regarded as the ultimate energetic materials. Although their syntheses normally require ultrahigh pressures of several hundred gigapascals (GPa) which prohibit direct materials application research on their stability metastability and fundamental properties are valuable for seeking extreme energetic materials through alternative synthetic routes. Various crystalline and amorphous polymeric nitrogens have been discovered between 100 and 200 GPa. Metastability at ambient conditions has been demonstrated for some of these phases. Cubic-gauche and black-phosphorus polymorphs of single-bonded nitrogen are two particularly interesting phases. Their large hystereses warrant further application-inspired basic research of nitrogen. In contrast although metallic hydrogen contains the highest-estimated energy density its picosecond lifetime and picogram quantity make its practical material application impossible at present. “Metallic hydrogen” remains a curiosity-driven basic research pursuit focusing on the pressure-induced evolution of the molecular hydrogen crystal and its electronic band structure from a low-density insulator with a very wide electronic band gap to a semiconductor with a narrow gap to a dense molecular metal and atomic metal and eventually to a previously unknown exotic state of matter. This great experimental challenge is driving relentless advancement in ultrahigh-pressure science and technology.
Analysis of Photon-driven Solar-to-hydrogen Production Methods in the Netherlands
Oct 2021
Publication
Hydrogen is deemed necessary for the realization of a sustainable society especially when renewable energy is used to generate hydrogen. As most of the photon-driven hydrogen production methods are not commercially available yet this study has investigated the techno economic and overall performance of four different solar-to hydrogen methods and photovoltaics-based electrolysis methods in the Netherlands. It was found that the photovoltaics-based electrolysis is the cheapest option with production cost of 9.31 $/kgH2. Production cost based on photo-catalytic water splitting direct bio-photolysis and photoelectrochemical water splitting are found to be 18.32 $/kgH2 18.45 $/kgH2 and 18.98 $/kgH2 respectively. These costs are expected to drop significantly in the future. Direct bio-photolysis (potential cost of 3.10 $/kgH2) and photo-catalytic water splitting (3.12 $/kgH2) may become cheaper than photovoltaics-based electrolysis. Based on preferences of three fictional technology investors i.e. a short-term a green and a visionary investor the overall performance of these methods are determined. Photovoltaics-based electrolysis is the most ideal option with photoelectrochemical water splitting a complementary option. While photovoltaics-based electrolysis has an advantage on the short-term because it is a non-integrated energy system on the long-term this might lead to relatively higher cost and performance limitations. Photochemical water splitting are integrated energy systems and have an advantage on the long-term because they need a relatively low theoretical overpotential and benefit from increasing temperatures. Both methods show performance improvements by the use of quantum dots. Bio-photolysis can be self-sustaining and can use wastewater to produce hydrogen but sudden temperature changes could lead to performance decrease.
Heat Recovery from a PtSNG Plant Coupled with Wind Energy
Nov 2021
Publication
Power to substitute natural gas (PtSNG) is a promising technology to store intermittent renewable electricity as synthetic fuel. Power surplus on the electric grid is converted to hydrogen via water electrolysis and then to SNG via CO2 methanation. The SNG produced can be directly injected into the natural gas infrastructure for long-term and large-scale energy storage. Because of the fluctuating behaviour of the input energy source the overall annual plant efficiency and SNG production are affected by the plant operation time and the standby strategy chosen. The re-use of internal (waste) heat for satisfying the energy requirements during critical moments can be crucial to achieving high annual efficiencies. In this study the heat recovery from a PtSNG plant coupled with wind energy based on proton exchange membrane electrolysis adiabatic fixed bed methanation and membrane technology for SNG upgrading is investigated. The proposed thermal recovery strategy involves the waste heat available from the methanation unit during the operation hours being accumulated by means of a two-tanks diathermic oil circuit. The stored heat is used to compensate for the heat losses of methanation reactors during the hot-standby state. Two options to maintain the reactors at operating temperature have been assessed. The first requires that the diathermic oil transfers heat to a hydrogen stream which is used to flush the reactors in order to guarantee the hot-standby conditions. The second option entails that the stored heat being recovered for electricity production through an Organic Rankine Cycle. The electricity produced is used to compensate the reactors heat losses by using electrical trace heating during the hot-standby hours as well as to supply energy to ancillary equipment. The aim of the paper is to evaluate the technical feasibility of the proposed heat recovery strategies and how they impact on the annual plant performances. The results showed that the annual efficiencies on an LHV basis were found to be 44.0% and 44.3% for the thermal storage and electrical storage configurations respectively.
HyDeploy2 Report: Exemption
Jun 2021
Publication
Exemption is requested by Northern Gas Networks Ltd (NGN) from the obligation set out in Regulation 8(1) of the Gas Safety (Management) Regulations 1996 (GSMR) to convey only natural gas that is compliant with the Interchangeability requirements of Part I of Schedule 3 of the GSMR within a section of the NGN gas distribution network near Winlaton (the “field trial area”). The field trial area is owned and operated by Northern Gas Networks Ltd. The proposed conveyance of non-compliant gas (hereafter called the “Winlaton Field Trial”) will last for one year and is part of the Network Innovation Competition Project “HyDeploy2”.<br/>The project the first two phases of which are funded under the UK Network Innovation Competition scheme aims to demonstrate that natural gas containing levels of hydrogen beyond the upper limit set out in Schedule 3 of in the Gas Safety (Management) Regulations (GSMR) can be distributed and utilised safely and efficiently in the UK gas distribution networks. The first phase of the HyDeploy project is currently underway and includes a 10-month field trial that of hydrogen injection into part of a private gas distribution system owned and operated by Keele University. The second phase of the HyDeploy project (HyDeploy2) continues on from the work of the first phase and is scheduled to conclude with two 12-month field trials in which hydrogen will be injected into public gas networks owned and operated by NGN and Cadent Gas.<br/>Click on the supplements tab to view the other documents from this report
Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization
Feb 2020
Publication
Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side forming an explosive gas. In this study a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement permeation cell pressure current density and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V while above the cell polarization is decisive. In addition a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. This approach indicates that thin membranes do not provide increased safety issues compared to thick membranes. However operating an N212-based system instead of an N117-based one can generate twice the amount of hydrogen at the same system efficiency while only one compressor stage must be added.
Navigating Algeria Towards a Sustainable Green Hydrogen Future to Empower North Africa and Europe's Clean Hydrogen Transition
Mar 2024
Publication
Algeria richly-endowed with renewable resources is well-positioned to become a vital green hydrogen provider to Europe. Aiming to aid policymakers stakeholders and energy sector participants this study embodies the first effort in literature to investigate the viability and cost-effectiveness of implementing green hydrogen production projects destined for exports to Europe via existing pipelines. A land suitability analysis utilizing multi-criteria decision making (MCDM) coupled with geographical information system (GIS) identified that over 43.55% of Algeria is highly-suitable for hydrogen production. Five optimal locations were investigated utilizing Hybrid Optimization of Multiple Electric Renewables (HOMER) with solar-hydrogen proving the most cost-effective option. Wind-based production offering higher output volumes reaching 968 kg/h requires turbine cost reductions of 17.50% (Ain Salah) to 54.50% (Djanet) to achieve a competitive levelized cost of hydrogen (LCOH) of $3.85/kg with PV systems. A techno-economic sensitivity analysis was conducted identifying Djanet as the most promising location for a 100 MW solar-hydrogen plant with a competitive LCOH ranging from $1.96/kg to $4.85/kg.
Study of the Permeation Flowrate of an Innovative Way to Store Hydrogen in Vehicles
Oct 2021
Publication
With the global warming of the planet new forms of energy are being sought as an alternative to fossil fuels. Currently hydrogen (H2) is seen as a strong alternative for fueling vehicles. However the major challenge in the use of H2 arises from its physical properties. An earlier study was conducted on the storage of H2 used as fuel in road vehicles powered by spark ignition engines or stacks of fuel cells stored under high pressure inside small spheres randomly packed in an envelope tank. Additionally the study evaluated the performance of this new storage system and compared it with other storage systems already applied by automakers in their vehicles. The current study aims to evaluate the H2 leaks from the same storage system when inserted in any road vehicle parked in conventional garages and to show the compliance of these leaks with European Standards provided that an appropriate choice of materials is made. The system’s compliance with safety standards was proved. Regarding the materials of each component of the storage system the best option from the pool of materials chosen consists of aluminum for the liner of the spheres and the envelope tank CFEP for the structural layer of the spheres and Si for the microchip.
A Financial Model for Lithium-ion Storage in a Photovoltaic and Biogas Energy System
May 2019
Publication
Electrical energy storage (EES) such as lithium-ion (Li-ion) batteries can reduce curtailment of renewables maximizing renewable utilization by storing surplus electricity. Several techno-economic analyses have been performed on EES but few have investigated the financial performance. This paper presents a state-of-the-art financial model obtaining novel and significative financial and economics results when applied to Li-ion EES. This work is a significant step forward since traditional analysis on EES are based on oversimplified and unrealistic economic models. A discounted cash flow model for the Li-ion EES is introduced and applied to examine the financial performance of three EES operating scenarios. Real-life solar irradiance load and retail electricity price data from Kenya are used to develop a set of case studies. The EES is coupled with photovoltaics and an anaerobic digestion biogas power plant. The results show the impact of capital cost: the Li-ion project is unprofitable in Kenya with a capital cost of 1500 $/kWh but is profitable at 200 $/kWh. The study shows that the EES will generate a higher profit if it is cycled more frequently (hence a higher lifetime electricity output) although the lifetime is reduced due to degradation.
Evaluation of Safety Measures of a Hydrogen Fueling Station Using Physical Modeling
Oct 2018
Publication
Hydrogen fueling stations are essential for operating fuel cell vehicles. If multiple safety measures in a hydrogen fueling station fail simultaneously it could lead to severe consequences. To analyze the risk of such a situation we developed a physical model of a hydrogen fueling station which when using the temperature pressure and flow rate of hydrogen could be simulated under normal and abnormal operating states. The physical model was validated by comparing the analytical results with the experimental results of an actual hydrogen fueling station. By combining the physical model with a statistical method we evaluated the significance of the safety measures in the event wherein multiple safety measures fail simultaneously. We determined the combinations of failures of safety measures that could lead to accidents and suggested a measure for preventing and mitigating the accident scenario.
Graphitic Carbon Nitride Heterojunction Photocatalysts for Solar Hydrogen Production
Sep 2021
Publication
Photocatalytic hydrogen production is considered as an ideal approach to solve global energy crisis and environmental pollution. Graphitic carbon nitride (g-C3N4) has received extensive consideration due to its facile synthesis stable physicochemical properties and easy functionalization. However the pristine g-C3N4 usually shows unsatisfactory photocatalytic activity due to the limited separation efficiency of photogenerated charge carriers. Generally introducing semiconductors or co-catalysts to construct g–C3N4–based heterojunction photocatalysts is recognized as an effective method to solve this bottleneck. In this review the advantages and characteristics of various types of g–C3N4–based heterojunction are analyzed. Subsequently the recent progress of highly efficient g–C3N4–based heterojunction photocatalysts in the field of photocatalytic water splitting is emphatically introduced. Finally a vision of future perspectives and challenges of g–C3N4–based heterojunction photocatalysts in hydrogen production are presented. Predictably this timely review will provide valuable reference for the design of efficient heterojunctions towards photocatalytic water splitting and other photoredox reactions.
Interlinking the Renewable Electricity and Gas Sectors: A Techno-Economic Case Study for Austria
Oct 2021
Publication
Achieving climate neutrality requires a massive transformation of current energy systems. Fossil energy sources must be replaced with renewable ones. Renewable energy sources with reasonable potential such as photovoltaics or wind power provide electricity. However since chemical energy carriers are essential for various sectors and applications the need for renewable gases comes more and more into focus. This paper determines the Austrian green hydrogen potential produced exclusively from electricity surpluses. In combination with assumed sustainable methane production the resulting renewable gas import demand is identified based on two fully decarbonised scenarios for the investigated years 2030 2040 and 2050. While in one scenario energy efficiency is maximised in the other scenario significant behavioural changes are considered to reduce the total energy consumption. A techno-economic analysis is used to identify the economically reasonable national green hydrogen potential and to calculate the averaged levelised cost of hydrogen (LCOH2) for each scenario and considered year. Furthermore roll-out curves for the necessary expansion of national electrolysis plants are presented. The results show that in 2050 about 43% of the national gas demand can be produced nationally and economically (34 TWh green hydrogen 16 TWh sustainable methane). The resulting national hydrogen production costs are comparable to the expected import costs (including transport costs). The most important actions are the quick and extensive expansion of renewables and electrolysis plants both nationally and internationally
A Policy Review of Green Hydrogen Economy in Southern Africa
Nov 2021
Publication
Renewable energy and clean energy have been on the global agenda for energy transition for quite a long time but recently gained strong momentum especially with the anticipated depletion of fossil fuels alongside increasing environmental degradation from their exploitation and the changing climate caused by their excessive carbon emissions. Despite this Africa’s pursuit to transition to a green economy using renewable energy resources still faces constraints that hamper further development and commercialization. These may include socio-economic technical political financial and institutional policy framework barriers. Although hydrogen demand is still low in Southern Africa the region can meet the global demands for green hydrogen as a major supplier because of its enormous renewable energy resource-base. This article reviews existing renewable energy resources and hydrogen energy policies in the Southern African Development Community (SADC). The significance of this review is that it explores how clean energy technologies that utilize renewable energy resources address the United Nations sustainable development goals (UN SDGs) and identifies the hydrogen energy policy gaps. This review further presents policy options and recommends approaches to enhance hydrogen energy production and ramp the energy transition from a fossil fuel-based economy to a hydrogen energy-based economy in Southern Africa. Concisely the transition can be achieved if the existing hydrogen energy policy framework gap is narrowed by formulating policies that are specific to hydrogen development in each country with the associated economic benefits of hydrogen energy clearly outlined.
HydroGenerally - Episode 3: Lift Off for Hydrogen in Aviation
Apr 2022
Publication
In this third episode Steffan Eldred and Hannah Abson from Innovate UK KTN are exploring the scale of the opportunity that hydrogen and aviation present alongside their special guest Katy Milne Head of Industrial Strategy at FlyZero.
The podcast can be found on their website
The podcast can be found on their website
The Impact of Process Heat on the Decarbonisation Potential of Offshore Installations by Hybrid Energy Systems
Dec 2021
Publication
An opportunity to decarbonise the offshore oil and gas sector lies in the integration of renewable energy sources with energy storage in a hybrid energy system (HES). Such concept enables maximising the exploitation of carbon-free renewable power while minimising the emissions associated with conventional power generation systems such as gas turbines. Offshore plants in addition to electrical and mechanical power also require process heat for their operation. Solutions that provide low-emission heat in parallel to power are necessary to reach a very high degree of decarbonisation. This paper investigates different options to supply process heat in offshore HES while the electric power is mostly covered by a wind turbine. All HES configurations include energy storage in the form of hydrogen tied to proton exchange membrane (PEM) electrolysers and fuel cells stacks. As a basis for comparison a standard configuration relying solely on a gas turbine and a waste heat recovery unit is considered. A HES combined with a waste heat recovery unit to supply heat proved efficient when low renewable power capacity is integrated but unable to deliver a total CO2 emission reduction higher than around 40%. Alternative configurations such as the utilization of gas-fired or electric heaters become more competitive at large installed renewable capacity approaching CO2 emission reductions of up to 80%.
What is the Energy Balance of Electrofuels Produced Through Power-to-fuel Integration with Biogas Facilities?
Nov 2021
Publication
The need to reduce the climate impact of the transport sector has led to an increasing interest in the utilisation of alternative fuels. Producing advanced fuels through the integration of anaerobic digestion and power-to-fuel technologies may offer a solution to reduce greenhouse gas emissions from difficult to decarbonise modes of transport such as heavy goods vehicles shipping and commercial aviation while also offering wider system benefits. This paper investigates the energy balance of power-to-fuel (power-to-methane power-to-methanol power-to-Fischer-Tropsch fuels) production integrated with a biogas facility co-digesting grass silage and dairy slurry. Through the integration of power-to-methane with anaerobic digestion an increase in system gross energy of 62.6% was found. Power-to-methanol integration with the biogas system increased the gross energy by 50% while power-to-Fischer-Tropsch fuels increased the gross energy yield by 32%. The parasitic energy demand for hydrogen production was highlighted as the most significant factor for integrated biogas and power-to-fuel facilities. Consuming electricity that would otherwise have been curtailed and optimising the anaerobic digestion process were identified as key to improving the energetic efficiency of all system configurations. However the broad cross-sectoral benefits of the overarching cascading circular economy system such as providing electrical grid stability and utilising waste resources must also be considered for a comprehensive perspective on the integration of anaerobic digestion and power-to-fuel.
Dynamic Mechanical Fatigue Behavior of Polymer Electrolyte Membranes for Fuel Cell Electric Vehicles Using a Gas Pressure-Loaded Blister
Nov 2021
Publication
This study reports on an innovative press-loaded blister hybrid system equipped with gas-chromatography (PBS-GC) that is designed to evaluate the mechanical fatigue of two representative types of commercial Nafion membranes under relevant PEMFC operating conditions (e.g. simultaneously controlling temperature and humidity). The influences of various applied pressures (50 kPa 100 kPa etc.) and blistering gas types (hydrogen oxygen etc.) on the mechanical resistance loss are systematically investigated. The results evidently indicate that hydrogen gas is a more effective blistering gas for inducing dynamic mechanical losses of PEM. The changes in proton conductivity are also measured before and after hydrogen gas pressure-loaded blistering. After performing the mechanical aging test a decrease in proton conductivity was confirmed which was also interpreted using small angle X-ray scattering (SAXS) analysis. Finally an accelerated dynamic mechanical aging test is performed using the homemade PBS-GC system where the hydrogen permeability rate increases significantly when the membrane is pressure-loaded blistering for 10 min suggesting notable mechanical fatigue of the PEM. In summary this PBS-GC system developed in-house clearly demonstrates its capability of screening and characterizing various membrane candidates in a relatively short period of time (<1.5 h at 50 kPa versus 200 h).
Power-to-gas in Electricity Markets Dominated by Renewables
Oct 2018
Publication
This paper analyses the feasibility of power-to-gas in electricity markets dominated by renewables. The business case of a power-to-gas plant that is producing hydrogen is evaluated by determining the willingness to pay for electricity and by comparing this to the level and volatility of electricity prices in a number of European day-ahead markets. The short-term willingness to pay for electricity depends on the marginal costs and revenues of the plant while the long-term willingness to pay for electricity also takes into account investment and yearly fixed operational costs and therefore depends on the expected number of operating hours. The latter ultimately determines whether or not large-scale investments in the power-to-gas technology will take place.<br/>We find that power-to-gas plants are not profitable under current market conditions: even under the most optimistic assumptions for the cost and revenue parameters power-to-gas plants need to run for many hours during the year at very low prices (i.e. the long-term willingness to pay for electricity is very low) that do not currently exist in Europe. In an optimistic future scenario regarding investment costs efficiency and revenues of power-to-gas however the long-term willingness to pay for electricity is higher than the lowest recently observed day-ahead electricity prices. When prices remain at this low level investments in power-to-gas can thus become profitable.
IGEM/TD/13 Edition 3 Supplement 1 - Pressure Regulating Installations for Hydrogen at Pressures Exceeding 7 Bar
Nov 2021
Publication
IGEM/TD/13 Standard applies to the safe design construction inspection testing operation and maintenance of pressure regulating installations (PRIs) in accordance with current knowledge and operational experience.
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations
You can purchase the standard here
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations
- with an upstream maximum operating pressure (MOP) not greater than 100 bar
- with an outlet pressure greater than or equal to 7 bar
- for use with Hydrogen or NG/H blends with a Hydrogen content greater than 10 %
- operating with a temperature range between -20°C and 120°C.
You can purchase the standard here
Conceptual Study and Development of an Autonomously Operating, Sailing Renewable Energy Conversion System
Jun 2022
Publication
With little time left for humanity to reduce climate change to a tolerable level a highly scalable and rapidly deployable solution is needed that can be implemented by any country. Offshore wind energy in international waters is an underused resource and could even be harnessed by landlocked countries. In this paper the use of sailing wind turbines operating autonomously in high seas to harvest energy is proposed. The electrical energy that is generated by the wind turbine is converted to a renewable fuel and stored onboard. Later the fuel will be transferred to shore or to other destinations of use. The presented idea is explored at the system level where the basic subsystems necessary are identified and defined such as energy conversion and storage as well as propulsion subsystems. Moreover various operating possibilities are investigated including a comparison of different sailing strategies and fuels for storage. Existing ideas are also briefly addressed and an example concept is suggested as well. In this paper the proposed sailing renewable energy conversion system is explored at a higher level of abstraction. Following up on this conceptual study more detailed investigations are necessary to determine whether the development of such a sailing renewable energy conversion system is viable from an engineering economic and environmental point of view.
A Novel Framework for Development and Optimisation of Future Electricity Scenarios with High Penetration of Renewables and Storage
May 2019
Publication
Although electricity supply is still dominated by fossil fuels it is expected that renewable sources will have a much larger contribution in the future due to the need to mitigate climate change. Therefore this paper presents a new framework for developing Future Electricity Scenarios (FuturES) with high penetration of renewables. A multi-period linear programming model has been created for power-system expansion planning. This has been coupled with an economic dispatch model PowerGAMA to evaluate the technical and economic feasibility of the developed scenarios while matching supply and demand. Application of FuturES is demonstrated through the case of Chile which has ambitious plans to supply electricity using only renewable sources. Four cost-optimal scenarios have been developed for the year 2050 using FuturES: two Business as usual (BAU) and two Renewable electricity (RE) scenarios. The BAU scenarios are unconstrained in terms of the technology type and can include all 11 options considered. The RE scenarios aim to have only renewables in the mix including storage. The results show that both BAU scenarios have a levelised cost of electricity (LCOE) lower than or equal to today’s costs ($72.7–77.3 vs $77.6/MWh) and include 81–90% of renewables. The RE scenarios are slightly more expensive than today’s costs ($81–87/MWh). The cumulative investment for the BAU scenarios is $123-$145 bn compared to $147-$157 bn for the RE. The annual investment across the scenarios is estimated at $4.0 ± 0.4 bn. Both RE scenarios show sufficient flexibility in matching supply and demand despite solar photovoltaics and wind power contributing around half of the total supply. Therefore the FuturES framework is a powerful tool for aiding the design of cost-efficient power systems with high penetration of renewables.
Russia’s Policy Transition to a Hydrogen Economy and the Implications of South Korea–Russia Cooperation
Dec 2021
Publication
Leading countries are developing clean energy to replace fossil fuels. In this context Russia is changing its energy policy towards fostering new energy resources such as hydrogen and helium. Hydrogen will not only contribute to Russia’s financial revenue by replacing natural gas but will also provide a basis for it to maintain its dominance over the international energy market by pioneering new energy markets. Russia is aiming to produce more than two million tons of hydrogen fuel for export to Europe and Asia by 2035. However it is facing many challenges including developing hydrogen fuel storage systems acquiring the technology required for exporting hydrogen and building trust in the fuel market. Meanwhile South Korea has a foundation for developing a hydrogen industry as it has the highest capacity in the world to produce fuel cells and the ability to manufacture LNG: (liquefied natural gas) carriers. Therefore South Korea and Russia have sufficient potential to create a new complementary and reciprocal cooperation model in the hydrogen fuel field. This study examines the present and future of Russia’s energy policy in this area as well as discusses South Korea and Russia’s cooperation plans in the hydrogen fuel sector and the related implications.
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.
THyGA - Intermediate Report on the Test of Technologies by Segment – Impact of the Different H2 Concentrations on Safety, Efficiency, Emissions and Correct Operation
Jan 2022
Publication
This report is the very first version of the document that will present the THyGA short-term test. These tests are carried out to observe how appliances react in the short term (few minutes to few hours) on different H2NG mixtures and long-term test are observing behaviour over several weeks. The analysis is based on the test of about 20 appliances only and is not yet covering extensively all the segments of the project. However most of the aspects of the testing are included in the present version that shall be considered as a draft working document to prepare the final report. We have tried to incorporate all aspects that are important to us but there may be more aspects and more analyses that could be added and will be added in the light of the comments and corrections we will gather after the dissemination of the document.
H-Mat Hydrogen Compatibility of NBR Elastomers
Sep 2021
Publication
The H2@Scale program of the U.S. Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office (HFTO) is supporting work on the hydrogen compatibility of polymers to improve the durability and reliability of materials for hydrogen infrastructure. The hydrogen compatibility program (H-Mat) seeks “to address the challenges of hydrogen degradation by elucidating the mechanisms of hydrogen-materials interactions with the goal of providing science-based strategies to design materials (micro)structures and morphology with improved resistance to hydrogen degradation.” Previous work on ethylene propylene diene indicated hydrogen interaction with plasticizer increased its migration to the surface and coalescing within the elastomer compound. New research on nitrile butadiene (NBR) has found hydrogen and pressure interactions with a series model rubber-material compounds to behave similarly in some compounds and improved in other compounds that is demonstrated through volume change and compression-set differences in the materials. Further studies were conducted using a helium-ion microscope (HeIM) which revealed significant morphological changes in the plasticizer-incorporating compounds after static exposure and pressure cycling as evidenced by time-of-flight secondary ion mass spectrometry. Additional studies using x-ray chromatography revealed that more micro-voids/-cracks developed after gas decompression in unfilled materials than in filled materials; transmission electron microscopy (TEM) probed at the nano-meter level showing change in filler distribution and morphology around Zinc-based particles.
Role of Hydrogen-based Energy Carriers as an Alternative Option to Reduce Residual Emissions Associated with Mid-century Decarbonization Goals
Mar 2022
Publication
Hydrogen-based energy carriers including hydrogen ammonia and synthetic hydrocarbons are expected to help reduce residual carbon dioxide emissions in the context of the Paris Agreement goals although their potential has not yet been fully clarified in light of their competitiveness and complementarity with other mitigation options such as electricity biofuels and carbon capture and storage (CCS). This study aimed to explore the role of hydrogen in the global energy system under various mitigation scenarios and technology portfolios using a detailed energy system model that considers various energy technologies including the conversion and use of hydrogen-based energy carriers. The results indicate that the share of hydrogen-based energy carriers generally remains less than 5% of global final energy demand by 2050 in the 2 ◦C scenarios. Nevertheless such carriers contribute to removal of residual emissions from the industry and transport sectors under specific conditions. Their share increases to 10–15% under stringent mitigation scenarios corresponding to 1.5 ◦C warming and scenarios without CCS. The transport sector is the largest consumer accounting for half or more of hydrogen production followed by the industry and power sectors. In addition to direct usage of hydrogen and ammonia synthetic hydrocarbons converted from hydrogen and carbon captured from biomass or direct air capture are attractive transport fuels growing to half of all hydrogen-based energy carriers. Upscaling of electrification and biofuels is another common cost-effective strategy revealing the importance of holistic policy design rather than heavy reliance on hydrogen.
Everything About Hydrogen Podcast: High-temperature Fuel Cells at High Altitudes
Jun 2021
Publication
HyPoint led by its CEO and co-founder Alex Ivanenko is at the cutting edge of the industry's efforts to find zero-emissions aircraft propulsion systems that do not sacrifice speed and power in the name of sustainability. HyPoint is a leading producer of high-temperature PEM fuel cells for aviation applications including for logistic drones air taxis electric vertical takeoff and landing vehicles (eVTOLs) and fixed-wing airplanes. On this episode of the EAH podcast the team speaks with Alex about the incredible pace of development and rapid innovation that he and his colleagues are driving in the hydrogen aviation space and how his company is leading the way in a highly complex and competitive race to decarbonize modern air travel.
The podcast can be found on their website
The podcast can be found on their website
An Experimental Study of Propagating Spherical Flames in Unconfined Hydrogen-oxygen Explosions
Sep 2021
Publication
The study to understand the flame propagation behaviors of hydrogen-oxygen explosions is required to make a precise risk assessment. Moreover although research has investigated the propagating spherical flames in unconfined hydrogen-air explosions no study to date has examined the hydrogen-oxygen explosions. The spherical flame propagation in unconfined hydrogen-oxygen explosions have been investigated using a soap bubble method. In the present experiments hydrogen-oxygen mixtures were filled in a 10 cm diameter soap bubble and ignited by an electric spark at the center. The flame propagation behaviors were measured by a high-speed Schlieren photography. The laminar burning velocities and critical flame radii for the onset of flame acceleration in unconfined hydrogen-oxygen explosions were estimated. Results demonstrated that the laminar burning velocities of hydrogenoxygen mixtures were much faster than those of hydrogen-air mixtures. In addition the shift value of maximum laminar burning velocity for hydrogen-oxygen mixtures towards a leaner equivalence ratio is observed. The experimental flame speeds for all experiments were increased owing to diffusionalthermal and Darrieus-Landau instabilities although the measured flame radii were small. The critical flame radius corresponding to the onset of flame acceleration decreased with the decrease in equivalence ratio.
Numerical Simulation of Hydrogen Leakage from Fuel Cell Vehicle in an Outdoor Parking Garage
Aug 2021
Publication
It is significant to assess the hydrogen safety of fuel cell vehicles (FCVs) in parking garages with a rapidly increased number of FCVs. In the present work a Flame Acceleration Simulator (FLACS) a computational fluid dynamics (CFD) module using finite element calculation was utilized to predict the dispersion process of flammable hydrogen clouds which was performed by hydrogen leakage from a fuel cell vehicle in an outdoor parking garage. The effect of leakage diameter (2 mm 3 mm and 4 mm) and parking configurations (vertical and parallel parking) on the formation of flammable clouds with a range of 4–75% by volume was considered. The emission was assumed to be directed downwards from a Thermally Activated Pressure Relief Device (TPRD) of a 70 MPa storage tank. The results show that the 0.7 m parking space stipulated by the current regulations is less than the safety space of fuel cell vehicles. Compared with a vertical parking configuration it is safer to park FCVs in parallel. It was also shown that release through a large TPRD orifice should be avoided as the proportion of the larger hydrogen concentration in the whole flammable domain is prone to more accidental severe consequences such as overpressure.
Current Research Progress in Magnesium Borohydride for Hydrogen Storage (A review)
Nov 2021
Publication
Hydrogen storage in solid-state materials is believed to be a most promising hydrogen-storage technology for high efficiency low risk and low cost. Mg(BH4)2 is regarded as one of most potential materials in hydrogen storage areas in view of its high hydrogen capacities (14.9 wt% and 145–147 kg cm3 ). However the drawbacks of Mg(BH4)2 including high desorption temperatures (about 250 C–580 C) sluggish kinetics and poor reversibility make it difficult to be used for onboard hydrogen storage of fuel cell vehicles. A lot of researches on improving the dehydrogenation reaction thermodynamics and kinetics have been done mainly including: additives or catalysts doping nanoconfining Mg(BH4)2 in nanoporous hosts forming reactive hydrides systems multi-cation/anion composites or other derivatives of Mg(BH4)2. Some favorable results have been obtained. This review provides an overview of current research progress in magnesium borohydride including: synthesis methods crystal structures decomposition behaviors as well as emphasized performance improvements for hydrogen storage.
How to Give a renewed Chance to Natural Gas as Feed for the Production of Hydrogen: Electric MSR Coupled with CO2 Mineralization
Sep 2021
Publication
Recent years have seen a growing interest in water electrolysis as a way to store renewable electric energy into chemical energy through hydrogen production. However today the share of renewable energy is still limited and there is the need to have a continuous use of H2 for industrial chemicals applications. Firstly the paper discusses the use of electrolysis - connected to a conventional grid - for a continuous H2 production in terms of associated CO2 emissions and compares such emissions with conventional methane steam reforming (MSR). Therefore it explores the possibility to use electrical methane steam reforming (eMSR) as a way to reduce the CO2 emissions. As a way to have zero emissions carbon mineralization of CO2 is coupled - instead of in-situ carbon capture and storage technology (CCS) - to eMSR; associated relevant cost of production is evaluated for different scenarios. It appears that to minimize such production cost carbonate minerals must be reused in the making of other industrial products since the amount of carbonates generated by the process is quite significant.
How to Decarbonise the UKs Freight Sector by 2050
Dec 2020
Publication
To achieve the UK’s net zero target vehicles including heavy-duty vehicles (HDVs) will need to be entirely decarbonised. The UK government has announced that it plans to phase out the sale of all new cars and vans with engines between 2030 and 2035. It has also announced its intention to consult on a similar phase-out for diesel-powered heavy-goods vehicles (HGVs). This study analyses policies and technologies which can contribute to the decarbonisation of the UK's inland freight sector.
It comprises an emissions modelling exercise and a cost analysis for total cost of ownership (TCO) of long-haul trucks. The study shows that for urban and regional deliveries battery electric trucks offer the best option to decarbonise. It also shows that battery electric trucks and those using an overhead catenary infrastructure are likely to be the most cost-effective pathway to decarbonise long-haul trucks by 2050 but that renewable hydrogen could also be an option.
Link to Document Download on Transport & Environment website
It comprises an emissions modelling exercise and a cost analysis for total cost of ownership (TCO) of long-haul trucks. The study shows that for urban and regional deliveries battery electric trucks offer the best option to decarbonise. It also shows that battery electric trucks and those using an overhead catenary infrastructure are likely to be the most cost-effective pathway to decarbonise long-haul trucks by 2050 but that renewable hydrogen could also be an option.
Link to Document Download on Transport & Environment website
Electrical Double Layer Mechanism Analysis of PEM Water Electrolysis for Frequency Limitation of Pulsed Currents
Nov 2021
Publication
This paper proposes a method for improving hydrogen generation using pulse current in a proton exchange membrane-type electrolyzer (PEMEL). Traditional methods of electrolysis using direct current are known as the simplest approach to produce hydrogen. However it is highly dependent on environmental variables such as the temperature and catalyst used to enhance the rate of electrolysis. Therefore we propose electrolysis using a pulse current that can apply several dependent variables rather than environmental variables. The proposed method overcomes the difficulties in selecting the frequency of the pulse current by deriving factors affecting hydrogen generation while changing the concentration generated by the cell interface during the pulsed water-electrolysis process. The correlation between the electrolyzer load and the frequency characteristics was analyzed and the limit value of the applicable frequency of the pulse current was derived through electrical modeling. In addition the operating characteristics of PEMEL could be predicted and the PEMEL using the proposed pulse current was verified through experiments.
Everything About Hydrogen Podcast: Toyota's global hydrogen ambitions
Feb 2020
Publication
On this weeks episode the team are talking all things hydrogen with Craig Scott the Group Manager for Toyota North America a global automotive giant and a recognised pioneer in the field of fuel cell mobility. On the show we get into the story of Toyota’s roll out of fuel cell mobility solutions in North America the challenges and opportunities that fuel cell vehicles can offer in the hydrogen market and the challenges around infrastructure. Importantly we also dive into the scaling up work that Toyota is undertaking and some of its plans for next steps on the mission to become the world’s leader in fuel cell mobility solutions. All this and more on the show!
The podcast can be found on their website
The podcast can be found on their website
Law and Policy Review on Green Hydrogen Potential in ECOWAS Countries
Mar 2022
Publication
This paper aims to review existing energy-sector and hydrogen-energy-related legal policy and strategy documents in the ECOWAS region. To achieve this aim current renewable-energyrelated laws acts of parliament executive orders presidential decrees administrative orders and memoranda were analyzed. The study shows that ECOWAS countries have strived to design consistent legal instruments regarding renewable energy in developing comprehensive legislation and bylaws to consolidate it and to encourage investments in renewable energy. Despite all these countries having a legislative basis for regulating renewable energy there are still weaknesses that revolve around the law and policy regarding its possible application in green hydrogen production and use. The central conclusion of this review paper is that ECOWAS member states presently have no official hydrogen policies nor bylaws in place. The hydrogen rise presents a challenge and opportunity for members to play an important role in the fast-growing global hydrogen market. Therefore these countries need to reform their regulatory frameworks and align their policies by introducing green hydrogen production in order to accomplish their green economy transition for the future and to boost the continent’s sustainable development.
Everything About Hydrogen Podcast: Flying Hy!
Feb 2021
Publication
Decarbonizing aviation is a big challenge. It is one of the most carbon intensive business sectors in the modern world and change comes slowly to the aviation industry. Hydrogen and fuel cell technologies offer a pathway to decarbonize regional flights in the not-so-distant future and big names are looking at potential solutions for long-haul flights in the longer term. But even if we build the aircraft that can use hydrogen as a fuel how do we get the fuel to them in a timely reliable and cost-efficient way?
The podcast can be found on their website
The podcast can be found on their website
The Implications of Ambitious Decarbonisation of Heat and Road Transport for Britain’s Net Zero Carbon Energy Systems
Oct 2021
Publication
Decarbonisation of heating and road transport are regarded as necessary but very challenging steps on the pathway to net zero carbon emissions. Assessing the most efficient routes to decarbonise these sectors requires an integrated view of energy and road transport systems. Here we describe how a national gas and electricity transmission network model was extended to represent multiple local energy systems and coupled with a national energy demand and road transport model. The integrated models were applied to assess a range of technologies and policies for heating and transport where the UK’s 2050 net zero carbon emissions target is met. Overall annual primary energy use is projected to reduce by between 25% and 50% by 2050 compared to 2015 due to ambitious efficiency improvements within homes and vehicles. However both annual and peak electricity demands in 2050 are more than double compared with 2015. Managed electric vehicle charging could save 14TWh/year in gas-fired power generation at peak times and associated emissions whilst vehicle-to-grid services could provide 10GW of electricity supply during peak hours. Together managed vehicle charging and vehicle-to-grid supplies could result in a 16% reduction in total annual energy costs. The provision of fast public charging facilities could reduce peak electricity demand by 17GW and save an estimated £650 million annually. Although using hydrogen for heating and transport spreads the hydrogen network costs between homeowners and motorists it is still estimated to be more costly overall compared to an all-electric scenario. Bio-energy electricity generation plants with carbon capture and storage are required to drive overall energy system emissions to net zero utilisation of which is lowest when heating is electrified and road transport consists of a mix of electric and hydrogen fuel-cell vehicles. The analysis demonstrates the need for an integrated systems approach to energy and transport policies and for coordination between national and local governments.
Everything About Hydrogen Podcast: Building Hydrogen Infrastructure with Black & Veatch
Feb 2020
Publication
On this weeks episode the team are talking all things hydrogen with Maryline Daviaud Lewett Director of Business Development for Transformative Technologies at Black & Veatch (B&V). On the show we discuss the role that Engineering Procurement and Construction (EPC) firms are playing in developing hydrogen and fuel cell infrastructure as well as discussing the unique aspects of developing projects in North America. As the leading EPC for hydrogen refuelling stations in North America and a wealth of experience across electric vehicle charging and hydrogen Maryline brings a uniquely well rounded perspective to the discussion and shares a wealth of insights for how the market may evolve. All this and more on the show!
The podcast can be found on their website
The podcast can be found on their website
Life Cycle Assessment and Water Footprint of Hydrogen Production Methods: From Conventional to Emerging Technologies
Oct 2020
Publication
A common sustainability issue arising in production systems is the efficient use of resources for providing goods or services. With the increased interest in a hydrogen (H2) economy the life-cycle environmental performance of H2 production has special significance for assisting in identifying opportunities to improve environmental performance and to guide challenging decisions and select between technology paths. Life cycle impact assessment methods are rapidly evolving to analyze multiple environmental impacts of the production of products or processes. This study marks the first step in developing process-based streamlined life cycle analysis (LCA) of several H2 production pathways combining life cycle impacts at the midpoint (17 problem-oriented) and endpoint (3 damage-oriented) levels using the state-of-the-art impact assessment method ReCiPe 2016. Steam reforming of natural gas coal gasification water electrolysis via proton exchange membrane fuel cell (PEM) solid oxide electrolyzer cell (SOEC) biomass gasification and reforming and dark fermentation of lignocellulosic biomass were analyzed. An innovative aspect is developed in this study is an analysis of water consumption associated with H2 production pathways by life-cycle stage to provide a better understanding of the life cycle water-related impacts on human health and natural environment. For water-related scope Water scarcity footprint (WSF) quantified using Available Water Remaining (AWARE) method was applied as a stand-alone indicator. The paper discusses the strengths and weaknesses of each production pathway identify the drivers of environmental impact quantify midpoint environmental impact and its influence on the endpoint environmental performance. The findings of this study could serve as a useful theoretical reference and practical basis to decision-makers of potential environmental impacts of H2 production systems.
Evaluating the Opportunity to Repurpose Gas Transmission Assets for Hydrogen Transportation
Sep 2021
Publication
The UK National Transmission System (NTS) is a key enabler to decarbonise the gas network in Great Britain (GB) in order to meet the UK government’s target of net-zero emissions by 2050. FutureGrid is National Grid’s research programme assessing the capability of the transmission system to transport hydrogen. Our goal is to accelerate the decarbonisation of power industry and heat by delivering a safe supply of energy to all customers both during and after the energy transition. FutureGrid will lead to a better understanding of what the technical parameters are around the ultimate role of the NTS in the energy system and how the transition can be managed. Under FutureGrid National Grid will construct a NTS hydrogen test facility at DNV’s Spadeadam testing and research site. NTS assets due to be decommissioned in early RIIO2 will be reconstructed to create a test network that can be used to answer some of the fundamental questions around safety and operation of a converted network. Flows of hydrogen/natural gas blends including 100% hydrogen will be tested for the first time in GB at transmission pressures. This system will connect to the existing H21 distribution network test facility at Spadeadam to prove a complete beach-to-meter network can be decarbonised to develop a comprehensive programme for the hydrogen transition. The project will provide a transmission facility which is a key enabler for more advanced hydrogen testing on industrial equipment such as hydrogen separation technology hydrogen compressors and/or purification of hydrogen for transport. Our paper will detail the current position and aims of the project.
Liquid Hydrogen as Prospective Energy Carrier: A Brief Review and Discussion of Underlying Assumptions Applied in Value Chain Analysis
Nov 2021
Publication
In the literature different energy carriers are proposed in future long-distance hydrogen value chains. Hydrogen can be stored and transported in different forms e.g. as compressed dense-phase hydrogen liquefied hydrogen and in chemically bound forms as different chemical hydrides. Recently different high-level value chain studies have made extrapolative investigations and compared such options with respect to energy efficiency and cost. Three recent journal papers overlap as the liquid hydrogen option has been considered in all three studies. The studies are not fully aligned in terms of underlying assumptions and battery limits. A comparison reveals partly vast differences in results for chain energy efficiency for long-distance liquid hydrogen transport which are attributable to distinct differences in the set of assumptions. Our comparison pinpoints the boiloff ratio i.e. evaporation losses due to heat ingress in liquid hydrogen storage tanks as the main cause of the differences and this assumption is further discussed. A review of spherical tank size and attributed boiloff ratios is presented for existing tanks of different vintage as well as for recently proposed designs. Furthermore the prospect for further extension of tanks size and reduction of boiloff ratio is discussed with a complementary discussion about the use of economic assumptions in extrapolative and predictive studies. Finally we discuss the impact of battery limits in hydrogen value chain studies and pinpoint knowledge needs and the need for a detailed bottom-up approach as a prerequisite for improving the understanding for pros and cons of the different hydrogen energy carriers.
Oxygen Carriers for Chemical-looping Water Splitting to Hydrogen Production: A Critical Review
Oct 2021
Publication
Chemical looping water splitting (CLWS) process using metal oxides or perovskites as oxygen carriers (OCs) is capable of producing pure H2 in an efficient simple and flexible way. The OCs are first reduced by hydrocarbon fuels and then oxidized by steam in a cyclic way. After the condensation of the gaseous mixture of steam and H2 from the oxidation step pure H2 is obtained. In recent years great efforts for CLWS have been made to improve the redox activity and stability of OCs. In this paper the development of the OCs for hydrogen production from CLWS were discussed. Effects of supports and additives on the performances of OCs were compared based on redox reactions in CLWS. Fe-based OCs with CeO2 Al2O3 ZrO2 CuO MoO3 Rh etc. are very attractive for the CLWS process. Issues and challenges for the development of OCs were analyzed.
Review of Hydrogen Production Techniques from Water Using Renewable Energy Sources and Its Storage in Salt Caverns
Feb 2022
Publication
Hydrogen is becoming an increasingly important energy carrier in sector integration for fuel cell transportation heat and electricity. Underground salt caverns are one of the most promising ways to store the hydrogen obtained from water electrolysis using power generation from renewable energy sources (RES). At the same time the production of hydrogen can be used to avoid energy curtailments during times of low electricity demand or low prices. The stored hydrogen can also be used during times of high energy demand for power generation e.g. with fuel cells to cover the fluctuations and shortages caused by low RES generation. This article presents an overview of the techniques that were used and proposed for using excess energy from RES for hydrogen production from water and its storage techniques especially in underground salt caverns for the aforementioned purpose and its feasibility. This paper compares and summarizes the competing technologies based on the current state-of-the-art identifies some of the difficulties in hydrogen production and storage and discusses which technology is the most promising. The related analysis compares cost and techno-economic feasibility with regard to hydrogen production and storage systems. The paper also identifies the potential technical challenges and the limitations associated with hydrogen integration into the power grid.
Hydrogen Diffusion and Its Effect on Hydrogen Embrittlement in DP Steels with Different Martensite Content
Dec 2020
Publication
The hydrogen diffusion behavior and hydrogen embrittlement susceptibility of dual phase (DP) steels with different martensite content were investigated using the slow strain-rate tensile test and hydrogen permeation measurement. Results showed that a logarithmic relationship was established between the hydrogen embrittlement index (IHE) and the effective hydrogen diffusion coefficient (Deff). When the martensite content is low ferrite/ martensite interface behaves as the main trap that captures the hydrogen atoms. Also when the Deff decreases IHE increases with increasing martensite content. However when the martensite content reaches approximately 68.3% the martensite grains start to form a continuous network Deff reaches a plateau and IHE continues to increase. This is mainly related to the reduction of carbon content in martensite and the length of ferrite/martensite interface which promotes the diffusion of hydrogen atoms in martensite and the aggregation of hydrogen atoms at the ferrite/martensite interface. Finally a model describing the mechanism of microstructure-driven hydrogen diffusion with different martensite distribution was established.
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