Denmark
Investigation of Turbulent Premixed Methane/Air and Hydrogen-enriched Methane/Air Flames in a Laboratory-scale Gas Turbine Model Combustor
Feb 2021
Publication
Methane and hydrogen-enriched (25 vol% and 50 vol% H2 -enriched CH4) methane/air premixed flames were investigated in a gas turbine model combustor under atmospheric conditions. The flame operability ranges were mapped at different Reynold numbers (Re) showing the dependence on Re and H2 concentrations. The effects of equivalence ratio (Ί) Re and H2 enrichment on flame structure were examined employing OH-PLIF measurement. For CH4/air cases the flame was stabilized with an M shape; while for H2 -enriched cases the flame transitions to a Рshape above a specific Ί. This transition was observed to influence significantly the flashback limits. The flame shape transition is most likely a result of H2 enrichment occurring due to the increase in flame speed higher resistance of the flame to the strain rate and change in the inner recirculation zone. Flow fields of CH4/air flames were compared between low and high Re cases employing high-speed PIV. The flashback events led by two mechanisms (combustion-induced vortex breakdown CIVB and boundary-layer flashback BLF) were observed and recorded using high-speed OH chemiluminescence imaging. It was found that the CIVB flashback occurred only for CH4 flames with M shape whereas the BLF occurs for all H2 -enriched flames with Рshape.
Life Cycle Assessment of Hydrogen Production and Consumption in an Isolated Territory
Apr 2018
Publication
Hydrogen produced from renewables works as an energy carrier and as energy storage medium and thus hydrogen can help to overcome the intermittency of typical renewable energy sources. However there is no comprehensive environmental performance study of hydrogen production and consumption. In this study detailed cradle to grave life cycle analyses are performed in an isolated territory. The hydrogen is produced on-site by Polymer Electrolyte Membrane (PEM) water electrolysis based on electricity from wind turbines that would otherwise have been curtailed and subsequently transported with gas cylinder by road and ferry. The hydrogen is used to provide electricity and heat through fuel cell stacks as well as hydrogen fuel for fuel cell vehicles. In order to evaluate the environmental impacts related to the hydrogen production and utilisation this work conducts an investigation of the entire life cycle of the described hydrogen production transportation and utilisation. All the processes related to the equipment manufacture operation maintenance and disposal are considered in this study.
A Survey Among Experts of Safety Related to the Use of Hydrogen as an Energy Carrier
Sep 2005
Publication
Based on the increasing need of energy for the future and the related risks to the environments due to burning of fossils fuels hydrogen is seen as an efficient and application related clean energy carrier that may be derived from renewable energy sources. A variety of applications connected with production and use of hydrogen and the related risks have been identified and a survey has been conducted among a number of experts as an internet exercise for unveiling the potential lack of necessary knowledge in order to handle hydrogen in a safe way concerning the various applications. The main results concern hazardous situations related to release and explosions of hydrogen in confined and semi-confined areas tunnels and garages and mitigation of hazardous situations i.e. preventions of accidents and reduction of consequences from accidents happening anyway.
Safety Aspects of Land-Use Planning Scenarios for a Future Infrastructure with Hydrogen Re-Fuelling Stations
Sep 2005
Publication
Hydrogen is currently gaining much attention as a possible future substitute for oil in the transport sector. Hydrogen is not a primary energy source but can be produced from other sources of energy. A future hydrogen economy will need the establishment of new infrastructures for producing storing distributing dispensing and using hydrogen. Hydrogen can be produced in large-scale centralized facilities or in smaller scale on-site systems. Large-scale production requires distribution in pipelines or trucks. A major challenge is to plan the new infrastructures to approach an even safer society regarding safe use of hydrogen. The paper will on the basis of some scenarios for hydrogen deployment highlight and evaluate safety aspects related to future hydrogen economy infrastructures.
Optimal Operation of the Hydrogen-based Energy Management System with P2X Demand Response and Ammonia Plant
Jul 2021
Publication
Hydrogen production is the key in utilizing an excess renewable energy. Many studies and projects looked at the energy management systems (EMSs) that allow to couple hydrogen production with renewable generation. In the majority of these studies however hydrogen demand is either produced for powering fuel cells or sold to the external hydrogen market. Hydrogen demand from actual industrial plants is rarely considered. In this paper we propose an EMS based on the industrial cluster of GreenLab Skive (GLS) that can minimize the systemâs operational cost or maximize its green hydrogen production. EMS utilizes a conventional and P2X demand response (DR) flexibility from electrolysis plant hydrogen storage tank electric battery and hydrogen-consuming plants to design the optimal schedule with maximized benefits. A potential addition to the existing components at GLS - an ammonia plant is modelled to identify its P2X potential and assess the economic viability of its construction. The results show a potential reduction of 51.5â61.6% for the total operational cost of the system and an increase of the share of green hydrogen by 10.4â37.6% due to EMS operation.
Power-to-fuels Via Solid-oxide Electrolyzer: Operating Window and Techno-economics
May 2019
Publication
Power-to-fuel systems via solid-oxide electrolysis are promising for storing excess renewable electricity by efficient electrolysis of steam (or co-electrolysis of steam and CO2) into hydrogen (or syngas) which can be further converted into synthetic fuels with plant-wise thermal integration. Electrolysis stack performance and durability determine the system design performance and long-term operating strategy; thus solid-oxide electrolyzer based power-to-fuels were investigated from the stack to system levels. At the stack level the data from a 6000-h stack testing under laboratory isothermal conditions were used to calibrate a quasi-2D model which enables to predict practical isothermal stack performance with reasonable accuracy. Feasible stack operating windows meeting various design specifications (e.g. specific syngas composition) were further generated to support the selection of operating points. At the system level with the chosen similar stack operating points various power-to-fuel systems including power-to-hydrogen power-to-methane power-to-methanol (dimethyl ether) and power-to-gasoline were compared techno-economically considering system-level heat integration. Several operating strategies of the stack were compared to address the increase in stack temperature due to degradation. The modeling results show that the system efficiency for producing H2 methane methanol/dimethyl ether and gasoline decreases sequentially from 94% (power-to-H2) to 64% (power-to-gasoline) based on a higher heating value. Co-electrolysis which allows better heat integration can improve the efficiency of the systems with less exothermic fuel-synthesis processes (e.g. methanol/dimethyl ether) but offers limited advantages for power-to-methane and power-to-gasoline systems. In a likely future scenario where the growing amount of electricity from renewable sources results in increasing periods of a negative electricity price solid oxide electrolyser based power-to-fuel systems are highly suitable for levelling the price fluctuations in an economic way.
Bridging the Maritime-Hydrogen Cost-Gap: Real Options Analysis of Policy Alternatives
May 2022
Publication
Alternative and especially renewable marine fuels are needed to reduce the environmental and climate impacts of the shipping sector. This paper investigates the business case for hydrogen as an alternative fuel in a new-built vessel utilizing fuel cells and liquefied hydrogen. A real option approach is used to model the optimal time and costs for investment as well as the value of deferring an investment as a result of uncertainty. This model is then used to assess the impact of a carbon tax on a ship ownerâs investment decision. A low carbon tax results in ship owners deferring investments which then slows the uptake of the technology. We recommend that policymakers set a high carbon tax at an early stage in order to help hydrogen compete with fossil fuels. A clear and timely policy design promotes further investments and accelerates the uptake of new technologies that can fulfill decarbonization targets.
Hydrogen - A Sustainable Energy Carrier
Jan 2017
Publication
Hydrogen may play a key role in a future sustainable energy system as a carrier of renewable energy to replace hydrocarbons. This review describes the fundamental physical and chemical properties of hydrogen and basic theories of hydrogen sorption reactions followed by the emphasis on state-of-the-art of the hydrogen storage properties of selected interstitial metallic hydrides and magnesium hydride especially for stationary energy storage related utilizations. Finally new perspectives for utilization of metal hydrides in other applications will be reviewed.
The Impact of Hydrogen Admixture into Natural Gas on Residential and Commercial Gas Appliances
Jan 2022
Publication
Hydrogen as a carbon-free fuel is commonly expected to play a major role in future energy supply e.g. as an admixture gas in natural gas grids. Which impacts on residential and commercial gas appliances can be expected due to the significantly different physical and chemical properties of hydrogen-enriched natural gas? This paper analyses and discusses blends of hydrogen and natural gas from the perspective of combustion science. The admixture of hydrogen into natural gas changes the properties of the fuel gas. Depending on the combustion system burner design and other boundary conditions these changes may cause higher combustion temperatures and laminar combustion velocities while changing flame positions and shapes are also to be expected. For appliances that are designed for natural gas these effects may cause risk of flashback reduced operational safety material deterioration higher nitrogen oxides emissions (NOx) and efficiency losses. Theoretical considerations and first measurements indicate that the effects of hydrogen admixture on combustion temperatures and the laminar combustion velocities are often largely mitigated by a shift towards higher air excess ratios in the absence of combustion control systems but also that common combustion control technologies may be unable to react properly to the presence of hydrogen in the fuel.
A Barrier Analysis of a Generic Hydrogen Refuelling Station
Sep 2009
Publication
Any technical installation need appropriate safety barriers installed to prevent or mitigate any adverse effects concerning people property and environment. In this context a safety barrier is a series of elements each consisting of a technical system or human action that implement a planned barrier function to prevent control or mitigate the propagation of a condition or event into an undesired condition or event. This is also important for new technologies as hydrogen refuelling stations being operated at very high pressures up to 900bar. In order to establish the needed barriers a hazard identification of the installation has to be carried out to identify the possible hazardous events. In this study this identification was done using the generic layout of a future large hydrogen refuelling station that has been developed by the EU NoE HySafe. This was based on experiences with smaller scale refuelling stations that has been in operation for several years e.g. being used in the former CUTE and ECTOS projects. Using this approach the object of the study is to support activities to further improve the safety performance of future larger refuelling stations. This will again help to inform the authorities and the public to achieve a proper public awareness and to support building up a realistic risk and safety perception of the safety on such future refuelling stations. In the second step the hazardous events that may take place and the barriers installed to stop hazards and their escalation are analysed also using in-house developed software to model the barriers and to quantify their performance. The paper will present an overview and discuss the state-of-the-art of the barriers established in the generic refuelling station.
The Role of Lock-in Mechanisms in Transition Processes: The Case of Energy for Road Transport
Jul 2015
Publication
This paper revisits the theoretical concepts of lock-in mechanisms to analyse transition processes in energy production and road transportation in the Nordic countries focussing on three technology platforms: advanced biofuels e-mobility and hydrogen and fuel cell electrical vehicles. The paper is based on a comparative analysis of case studies.<br/>The main lock-in mechanisms analysed are learning effects economies of scale economies of scope network externalities informational increasing returns technological interrelatedness collective action institutional learning effects and the differentiation of power.<br/>We show that very different path dependencies have been reinforced by the lock-in mechanisms. Hence the characteristics of existing regimes set the preconditions for the development of new transition pathways. The incumbent socio-technical regime is not just fossil-based but may also include mature niches specialised in the exploitation of renewable sources. This implies a need to distinguish between lock-in mechanisms favouring the old fossil-based regime well-established (mature) renewable energy niches or new pathways.
Estimation of Uncertainty in Risk Assessment of Hydrogen Applications
Sep 2011
Publication
Hydrogen technologies such as hydrogen fuelled vehicles and refuelling stations are being tested in practice in a number of projects (e.g. HyFleet-Cute and Whistler project) giving valuable information on the reliability and maintenance requirements. In order to establish refuelling stations the permitting authorities request qualitative and quantitative risk assessments to show the safety and acceptability in terms of failure frequencies and respective consequences. For new technologies not all statistical data can be established or are available in good quality causing assumptions and extrapolations to be made. Therefore the risk assessment results contain varying degrees of uncertainty as some components are well established while others are not. The paper describes a methodology to evaluate the degree of uncertainty in data for hydrogen applications based on the bias concept of the total probability and the NUSAP concept to quantify uncertainties of new not fully qualified hydrogen technologies and implications to risk management.
Hydrogen Fueling Standardization: Enabling ZEVs with "Same as Today" Fueling and FCEV Range and Safety
Oct 2015
Publication
Zero Emission Vehicles (ZEVs) are necessary to help reduce the emissions in the transportation sector which is responsible for 40% of overall greenhouse gas emissions. There are two types of ZEVs Battery Electric Vehicles (BEVs) and Fuel Cell Electric Vehicles (FCEVs) Commercial Success of BEVs has been challenging thus far also due to limited range and very long charging duration. FCEVs using H2 infrastructure with SAE J2601 and J2799 standards can be consistently fuelled in a safe manner fast and resulting in a range similar to conventional vehicles. Specifically fuelling with SAE J2601 with the SAE J2799 enables FCEVs to fill with hydrogen in 3-5 minutes and to achieve a high State of Charge (SOC) resulting in 300+ mile range without exceeding the safety storage limits. Standardized H2 therefore gives an advantage to the customer over electric charging. SAE created this H2 fuelling protocol based on modelling laboratory and field tests. These SAE standards enable the first generation of commercial FCEVs and H2 stations to achieve a customer acceptable fueling similar to today's experience. This report details the advantages of hydrogen and the validation of H2 fuelling for the SAE standards.
The Role of Effectiveness Factor on the Modeling of Methanol Steam Reforming Over CuO/ZnO/Al2O3 Catalyst in a Multi-tubular Reactor
Jan 2022
Publication
A pseudo-homogeneous model for the methanol steam reforming process was developed based on reaction kinetics over a CuO/ZnO/Al2O3 catalyst and non-adiabatic heat and mass transfer performances in a co-current packed-bed reactor. A Thiele modulus method and an intraparticle distribution method were applied for predicting the effectiveness factors for main reactions and providing insights into the diffusion-reaction process in a cylindrical catalyst pellet. The results of both methods are validated and show good agreements with the experimental data but the intraparticle distribution method provides better predictions. Results indicate that increases in catalyst size and bulk fluid temperature amplify the impact of intraparticle diffusion limitations showing a decrease in effectiveness factors. To satisfy the requirements of a high temperature polymer electrolyte membrane fuel cell stack the optimized operating conditions which bring the methanol and CO concentrations to less than 1% vol in the reformate stream are determined based on the simulation results.
Complex Metal Hydrides for Hydrogen, Thermal and Electrochemical Energy Storage
Oct 2017
Publication
Hydrogen has a very diverse chemistry and reacts with most other elements to form compounds which have fascinating structures compositions and properties. Complex metal hydrides are a rapidly expanding class of materials approaching multi-functionality in particular within the energy storage field. This review illustrates that complex metal hydrides may store hydrogen in the solid state act as novel battery materials both as electrolytes and electrode materials or store solar heat in a more efficient manner as compared to traditional heat storage materials. Furthermore it is highlighted how complex metal hydrides may act in an integrated setup with a fuel cell. This review focuses on the unique properties of light element complex metal hydrides mainly based on boron nitrogen and aluminum e.g. metal borohydrides and metal alanates. Our hope is that this review can provide new inspiration to solve the great challenge of our time: efficient conversion and large-scale storage of renewable energy.
Technical and Economic Analysis of One-Stop Charging Stations for Battery and Fuel Cell EV with Renewable Energy Sources
Jun 2020
Publication
Currently most of the vehicles make use of fossil fuels for operations resulting in one of the largest sources of carbon dioxide emissions. The need to cut our dependency on these fossil fuels has led to an increased use of renewable energy sources (RESs) for mobility purposes. A technical and economic analysis of a one-stop charging station for battery electric vehicles (BEV) and fuel cell electric vehicles (FCEV) is investigated in this paper. The hybrid optimization model for electric renewables (HOMER) software and the heavy-duty refueling station analysis model (HDRSAM) are used to conduct the case study for a one-stop charging station at Technical University of Denmark (DTU)-RisĂž campus. Using HOMER a total of 42 charging station scenarios are analyzed by considering two systems (a grid-connected system and an off-grid connected system). For each system three different charging station designs (design A-hydrogen load; design B-an electrical load and design C-an integrated system consisting of both hydrogen and electrical load) are set up for analysis. Furthermore seven potential wind turbines with different capacity are selected from HOMER database for each system. Using HDRSAM a total 18 scenarios are analyzed with variation in hydrogen delivery option production volume hydrogen dispensing option and hydrogen dispensing option. The optimal solution from HOMER for a lifespan of twenty-five years is integrated into design C with the grid-connected system whose cost was $986065. For HDRSAM the optimal solution design consists of tube trailer as hydrogen delivery with cascade dispensing option at 350 bar together with high production volume and the cost of the system was $452148. The results from the two simulation tools are integrated and the overall cost of the one-stop charging station is achieved which was $2833465. The analysis demonstrated that the one-stop charging station with a grid connection is able to fulfil the charging demand cost-effectively and environmentally friendly for an integrated energy system with RESs in the investigated locations.
Risk Analysis of Complex Hydrogen Infrastructures
Oct 2015
Publication
Building a network of hydrogen refuelling stations is essential to develop the hydrogen economy within transport. Additional hydrogen is regarded a likely key component to store and convert back excess electrical power to secure future energy supply and to improve the quality of biomass-based fuels. Therefore future hydrogen supply and distribution chains will have to address several objectives. Such a complexity is a challenge for risk assessment and risk management of these chains because of the increasing interactions. Improved methods are needed to assess the supply chain as a whole. The method of âFunctional modellingâ is discussed in this paper. It will be shown how it could be a basis for other decision support methods for comprehensive risk and sustainability assessments.
Safety-Barrier Diagrams for Documenting Safety of Hydrogen Applications
Sep 2007
Publication
Safety-barrier diagrams have proven to be a useful tool in documenting the safety measures taken to prevent incidents and accidents in process industry. In Denmark they are used to inform the authorities and the nonexperts on safety relevant issues as safety-barrier diagrams are less complex compared to fault trees and are easy to understand. Internationally there is a growing interest in this concept with the use of so-called âbowtieâ diagrams which are a special case of safety-barrier diagrams. Especially during the on-going introduction of new hydrogen technologies or applications as e.g. hydrogen refueling stations this technique is considered a valuable tool to support the communication with authorities and other stakeholders during the permitting process. Another advantage of safety-barrier diagrams is that there is a direct focus on those system elements that need to be subject to safety management in terms of design and installation operational use inspection and monitoring and maintenance. Safety-barrier diagrams support both quantitative and qualitative or deterministic approaches. The paper will describe the background and syntax of the methodology and thereafter the use of such diagrams for hydrogen technologies are demonstrated.
A Modeling Study of Lifetime and Performance Improvements of Solid Oxide Fuel Cell by Reversed Pulse Operation
Jan 2022
Publication
Chromium poisoning of the air electrode is a primary degradation mechanism for solid oxide cells (SOCs) operating under fuel cell mode. Recent experimental findings show that reversed pulse operation for SOCs operated as electrolyser cells can reverse this degradation and extend the lifetime. Here we use a multiphysics model of an SOC to investigate the effects of reversed pulse operation for alleviating chromium poisoning of the air electrode. We study the effects of time fraction of the operation under fuel cell and electrolysis modes cyclic operation starting after a certain duration and fuel cell and electrolysis current densities on the cell lifetime total power and hydrogen production. Our modeling shows that reversed pulse operation enhances cell lifetime and total power for all different cases considered in this study. Moreover results suggest that the cell lifetime total power and hydrogen production can be increased by reversed pulse operation at longer operation times under electrolysis mode cyclic operation starting from the beginning and lower electrolysis current densities. All in all this paper documents and establishes a computational framework that can serve as a platform to assess and quantify the increased profitability of SOCs operating under a co-production operation through reversed pulse operation.
Overview of Power Electronic Converter Topologies Enabling Large-Scale Hydrogen Production via Water Electrolysis
Feb 2022
Publication
Renewable power-to-hydrogen (P2H) technology is one of the most promising solutions for fulfilling the increasing global demand for hydrogen and to buffer large-scale fluctuating renewable energies. The high-power high-current ac/dc converter plays a crucial role in P2H facilities transforming medium-voltage (MV) ac power to a large dc current to supply hydrogen electrolyzers. This work introduces the general requirements and overviews several power converter topologies for P2H systems. The performances of different topologies are evaluated and compared from multiple perspectives. Moreover the future trend of eliminating the line frequency transformer (LFT) is discussed. This work can provide guidance for future designing and implementing of power-electronics-based P2H systems.
Magnesium Based Materials for Hydrogen Based Energy Storage: Past, Present and Future
Jan 2019
Publication
Volodymyr A. Yartys,
Mykhaylo V. Lototskyy,
Etsuo Akiba,
Rene Albert,
V. E. Antonov,
Jose-RamĂłn Ares,
Marcello Baricco,
Natacha Bourgeois,
Craig Buckley,
José Bellosta von Colbe,
Jean-Claude Crivello,
Fermin Cuevas,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
David M. Grant,
BjĂžrn Christian Hauback,
Terry D. Humphries,
Isaac Jacob,
Petra E. de Jongh,
Jean-Marc Joubert,
Mikhail A. Kuzovnikov,
Michel Latroche,
Mark Paskevicius,
Luca Pasquini,
L. Popilevsky,
Vladimir M. Skripnyuk,
Eugene I. Rabkin,
M. Veronica Sofianos,
Alastair D. Stuart,
Gavin Walker,
Hui Wang,
Colin Webb,
Min Zhu and
Torben R. Jensen
Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The âMagnesium groupâ of international experts contributing to IEA Task 32 âHydrogen Based Energy Storageâ recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH2 nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH2 are presented.
Artificial Neural Network Based Optimization of a Six-step Two-bed Pressure Swing Adsorption System for Hydrogen Purification
Apr 2021
Publication
The pressure swing adsorption (PSA) system is widely applied to separate and purify hydrogen from gaseous mixtures. The extended Langmuir equation fitted from the extended Langmuir-Freundlich isotherm has been used to predict the adsorption isothermal of hydrogen and methane on the zeolite 5A adsorbent bed. A six-step two-bed PSA model for hydrogen purification is developed and validated by comparing its simulation results with other works. The effects of the adsorption pressure the P/F ratio the adsorption step time and the pressure equalization time on the performance of the hydrogen purification system are studied. A four-step two-bed PSA model is taken into consideration and the six-step PSA system shows higher about 13% hydrogen recovery than the four-step PSA system. The performance of the vacuum pressure swing adsorption (VPSA) system is compared with that of the PSA system the VPSA system shows higher hydrogen purity than the PSA system. Based on the validated PSA model a dataset has been produced to train the artificial neural network (ANN) model. The effects of the number of neurons in the hidden layer and the number of samples used for training ANN model on the predicted performance of ANN model are investigated. Then the well-trained ANN model with 6 neurons in the hidden layer is applied to predict the performance of the PSA system for hydrogen purification. Multi-objective optimization of hydrogen purification system is performed based on the trained ANN model. The artificial neural network can be considered as a very effective method for predicting and optimizing the performance of the PSA system for hydrogen purification.
Optimization of Geothermal- and Solar-driven Clean Electricity and Hydrogen Production Multi-generation Systems to Address the Energy Nexus
Jan 2022
Publication
Given the limited sources of fossil fuels mankind should find new ways to meet its energy demands. In this regard geothermal and solar energy are acknowledged as reliable safe promising and clean means for this purpose. In this research study a comparative analysis is applied on geothermal and solar-driven multi-generation systems for clean electricity and hydrogen production through energy and exergy assessments. The system consists of an organic Rankine cycle a proton electrolyte membrane electrolyzer and a thermoelectric generator subsystem. The Engineering Equation Solver software has been utilized in order to model the system and obtain the output contours sensitivity analysis and exergy destruction. The results were calculated considering the ambient temperature of Bandar Abbas city as a case study considering the geothermal system due to better performance in comparison to the solar system. According to the sensitivity analysis the turbine efficiency evaporator inlet temperature thermoelectric generator suitability criterion pump efficiency and evaporator inlet mass flow rate are the most influential parameters. Also the exergy analysis showed that the utmost system's exergy destruction is pertinent to the evaporator and the least is related to the pump. In addition the system produces 352816 kWh and 174.913 kg of electrical power and hydrogen during one year.
Hydrogen-fueled Car Fire Spread to Adjacent Vehicles in Car Parks
Sep 2019
Publication
Car park fires are known to be dangerous due to the risk of fast fire spread from one car to another. In general no fatalities are recorded in such fires but they may have a great cost in relation to damaged cars and structural repair. A very recent example is the Liverpool multi-storey car park fire from December 31 2017. It destroyed 1400 cars and parts of the building structure collapsed. This questions the validity of current design praxis of car parks. Literature studies assumes a 12 minutes period for the fire spread from one gasoline fuelled car to another. Statistical research and test from the European commission of steel structures states that in an open car park at most 3-4 vehicles are expected to be on fire at the same time.<br/>A number of investigations have been made concerning vehicles performance in car park fires but only a few are concerned with hydrogen-fuelled vehicles (HFV). It is therefore important to investigate how these new vehicles may contribute to potential fire spread scenario. The aim of the paper is to report the outcome of car park fire spread simulations involving common fuelled and hydrogen fuelled cars. The case study is based on a typical car park found in Denmark. The simulation applied numerical models implemented in the Fire Dynamic Simulator (FDS). In particular the focus of the study is on the influence of the parking distance to fire spread to adjacent vehicles in case a TPRD is activated during a car fire. The results help understanding whether different design rules should be envisaged for such structures or how a sufficient safety level can be obtained by ensuring specific parking condition for the hydrogen-fuelled cars.
Analysing Long-term Opportunities for Offshore Energy System Integration in the Danish North Sea
Aug 2021
Publication
This study analyzes future synergies between the Oil and Gas (O&G) and renewables sectors in a Danish context and explores how exploiting these synergies could lead to economic and environmental benefits. We review and highlight relevant technologies and related projects and synthesize the state of the art in offshore energy system integration. All of these preliminary results serve as input data for a holistic energy system analysis in the Balmorel modeling framework. With a timeframe out to 2050 and model scope including all North Sea neighbouring countries this analysis explores a total of nine future scenarios for the North Sea energy system. The main results include an immediate electrification of all operational Danish platforms by linking them to the shore and/or a planned Danish energy island. These measures result in cost and CO2 emissions savings compared to a BAU scenario of 72% and 85% respectively. When these platforms cease production this is followed by the repurposing of the platforms into hydrogen generators with up to 3.6 GW of electrolysers and the development of up to 5.8 GW of floating wind. The generated hydrogen is assumed to power the future transport sector and is delivered to shore in existing and/or new purpose-built pipelines. The contribution of the O&G sector to this hydrogen production amounts to around 19 TWh which represents about 2% of total European hydrogen demand for transport in 2050. The levelized costs (LCOE) of producing this hydrogen in 2050 are around 4 âŹ2020/kg H2 which is around twice those expected in similar studies. But this does not account for energy policies that may incentivize green hydrogen production in the future which would serve to reduce this LCOE to a level that is more competitive with other sources.
Market Segmentation of Domestic and Commercial Natural Gas Appliances
Jan 2021
Publication
The main goal of the project is to enable the wide adoption of H2NG (hydrogen in natural gas) blends by closing knowledge gaps regarding technical impacts on residential and commercial gas appliances. The project consortium will identify and recommend appropriate codes and standards that should be adapted to answer the needs and develop a strategy for addressing the challenges for new and existing appliances.<br/>This deliverable on market segmentation is part of work package 2 and provides a quantitative segmentation of the gas appliance market in terms of appliance population numbers. It therefore prepares the project partners to perform the subsequent selection of the most representative product types to be tested in the laboratories of the THyGA partners.<br/>The classification is developed to categorise appliances installed in the field based on available statistics calculation methods and estimations. As a result appliance populations are provided for each technology segment that draw a representative picture of the installed end-use appliances within the European Union in 2020.
International Association for Hydrogen Safety âResearch Priorities Workshopâ, September 2018, Buxton, UK
Sep 2018
Publication
Hydrogen has the potential to be used by many countries as part of decarbonising the future energy system. Hydrogen can be used as a fuel âvectorâ to store and transport energy produced in low-carbon ways. This could be particularly important in applications such as heating and transport where other solutions for low and zero carbon emission are difficult. To enable the safe uptake of hydrogen technologies it is important to develop the international scientific evidence base on the potential risks to safety and how to control them effectively. The International Association for Hydrogen Safety (known as IA HySAFE) is leading global efforts to ensure this. HSE hosted the 2018 IA HySAFE Biennial Research Priorities Workshop. A panel of international experts presented during nine key topic sessions: (1) Industrial and National Programmes; (2) Applications; (3) Storage; (4) Accident Physics â Gas Phase; (5) Accident Physics â Liquid/ Cryogenic Behaviour; (6) Materials; (7) Mitigation Sensors Hazard Prevention and Risk Reduction; (8) Integrated Tools for Hazard and Risk Assessment; (9) General Aspects of Safety.<br/>This report gives an overview of each topic made by the session chairperson. It also gives further analysis of the totality of the evidence presented. The workshop outputs are shaping international activities on hydrogen safety. They are helping key stakeholders to identify gaps in knowledge and expertise and to understand and plan for potential safety challenges associated with the global expansion of hydrogen in the energy system.
Determination Of Hazardous Zones For A Generic Hydrogen Station â A Case Study
Sep 2007
Publication
A method for determination of hazardous zones for hydrogen installations has been studied. This work has been carried out within the NoE HySafe. The method is based on the Italian Method outlined in Guide 31-30(2004) Guide 31â35(2001) Guide 31-35/A(2001) and Guide 31-35/A; V1(2003). Hazardous zones for a âgeneric hydrogen refuelling stationâ(HRS) are assessed based on this method. The method is consistent with the EU directive 1999/92/EC âSafety and Health Protection of Workers potentially at risk from explosive atmospheresâ which is the basis for determination of hazardous zones in Europe. This regulation is focused on protection of workers and is relevant for hydrogen installations such as hydrogen refuelling stations repair shops and other stationary installations where some type of work operations will be involved. The method is also based on the IEC standard and European norm IEC/EN60079-10 âElectrical apparatus for explosive gas atmospheres. Part 10 Classification of hazardous areasâ. This is a widely acknowledged international standard/norm and it is accepted/approved by Fire and Safety Authorities in Europe and also internationally. Results from the HySafe work and other studies relevant for hydrogen and hydrogen installations have been included in the case study. Sensitivity studies have been carried out to examine the effect of varying equipment failure frequencies and leak sizes as well as environmental condition (ventilation obstacles etc.). The discharge and gas dispersion calculations in the Italian Method are based on simple mathematical formulas. However in this work also CFD (Computational Fluid Dynamics) and other simpler numerical tools have been used to quantitatively estimate the effect of ventilation and of different release locations on the size of the flammable gas cloud. Concentration limits for hydrogen to be used as basis for the extent of the hazardous zones in different situations are discussed.
Discrete Event Simulation in Support to Hydrogen Supply Reliability
Sep 2009
Publication
Discrete Event Simulation (DES) environments are rapidly developing and they appear to be promising tools for developing reliability and risk analysis models of safety-critical systems. DES models are an alternative to the conventional methods such as fault and event trees Bayesian networks and cause-consequence diagrams that could be used to assess the reliability of fuel supply. DES models can rather easily account for the dynamic dimensions and other important features that can hardly be captured by the conventional models. The paper describes a novel approach to estimate gas supply security and the reliability/safety of gas installations and argues that this approach can be transferred to estimate future hydrogen supply reliability. The core of the approach is a DES model of gas or other fuel propulsion through a pipeline to the customers and failures of the components of the pipeline. We will argue in the paper that the experience gained in the modelling of gas supply reliability is very relevant to the security and safety of a future hydrogen supply and worth being employed in this area.
Uncertainties in Risk Assessment of Hydrogen Discharges from Pressurized Storage Vessels Ranging from Cryogenic to Ambient Temperatures
Sep 2013
Publication
Evaluations of the uncertainties resulting from risk assessment tools to predict releases from the various hydrogen storage types are important to support risk informed safety management. The tools have to predict releases from a wide range of storage pressures (up to 80 MPa) and temperatures (at 20K) e.g. the cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types. The vessel dynamics are modelled to evaluate the performance of various EOS to predict exit pressures and temperatures. The results are compared to experimental data and results from CFD calculations.
Development of a Generalized Integral Jet Model
Sep 2017
Publication
Integral type models to describe stationary plumes and jets in cross-flows (wind) have been developed since about 1970. These models are widely used for risk analysis to describe the consequences of many different scenarios. Alternatively CFD codes are being applied but computational requirements still limit the number of scenarios that can be dealt with using CFD only. The integral models however are not suited to handle transient releases such as releases from pressurized equipment where the initially high release rate decreases rapidly with time. Further on gas ignition a second model is needed to describe the rapid combustion of the flammable part of the plume (flash fire) and a third model has to be applied for the remaining jet fire. The objective of this paper is to describe the first steps of the development of an integral-type model describing the transient development and decay of a jet of flammable gas after a release from a pressure container. The intention is to transfer the stationary models to a fully transient model capable to predict the maximum extension of short-duration high pressure jets. The model development is supported by conducting a set of transient ignited and unignited spontaneous releases at initial pressures between 25bar and 400bar. These data forms the basis for the presented model development approach.
Application of Hydrides in Hydrogen Storage and Compression: Achievements, Outlook and Perspectives
Feb 2019
Publication
José Bellosta von Colbe,
Jose-RamĂłn Ares,
Jussara Barale,
Marcello Baricco,
Craig Buckley,
Giovanni Capurso,
Noris Gallandat,
David M. Grant,
Matylda N. Guzik,
Isaac Jacob,
Emil H. Jensen,
Julian Jepsen,
Thomas Klassen,
Mykhaylo V. Lototskyy,
Kandavel Manickam,
Amelia Montone,
Julian Puszkiel,
Martin Dornheim,
Sabrina Sartori,
Drew Sheppard,
Alastair D. Stuart,
Gavin Walker,
Colin Webb,
Heena Yang,
Volodymyr A. Yartys,
Andreas ZĂŒttel and
Torben R. Jensen
Metal hydrides are known as a potential efficient low-risk option for high-density hydrogen storage since the late 1970s. In this paper the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s interstitial metal hydrides are known as base materials for Ni â metal hydride rechargeable batteries. For hydrogen storage metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units i. e. for stationary applications.<br/>With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004 the use of metal hydrides for hydrogen storage in mobile applications has been established with new application fields coming into focus.<br/>In the last decades a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more partly less extensively characterized.<br/>In addition based on the thermodynamic properties of metal hydrides this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles.<br/>In the frame of the âHydrogen Storage Systems for Mobile and Stationary Applicationsâ Group in the International Energy Agency (IEA) Hydrogen Task 32 âHydrogen-based energy storageâ different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.
Reversible Ammonia-based and Liquid Organic Hydrogen Carriers for High-density Hydrogen Storage: Recent Progress
Feb 2019
Publication
Liquid hydrogen carriers are considered to be attractive hydrogen storage options because of their ease of integration into existing chemical transportation infrastructures when compared with liquid or compressed hydrogen. The development of such carriers forms part of the work of the International Energy Agency Task 32: Hydrogen-Based Energy Storage. Here we report the state-of-the-art for ammonia-based and liquid organic hydrogen carriers with a particular focus on the challenge of ensuring easily regenerable high-density hydrogen storage.
Power-to-X in Energy Hubs: A Danish Case Study of Renewable Fuel Production
Feb 2023
Publication
The European Commission recently proposed requirements for the production of renewable fuels as these are required to decarbonize the hard-to-electrify parts of the industrial and heavy transport sectors. Power-to-X (P2X) energy hubs enable efficient synergies between energy infrastructures production facilities and storage options. In this study we explore the optimal operation of an energy hub by leveraging the flexibility of P2X including hydrogen methanol and ammonia synthesizers by analyzing potential revenue streams such as the day-ahead and ancillary services markets. We propose EnerHub2X a mixed-integer linear program that maximizes the hubâs profit based on current market prices considering the technical constraints of P2X such as unit commitment and non-linear efficiencies. We investigate a representative Danish energy hub and find that without price incentives it mainly sells renewable electricity and produces compressed hydrogen. A sufficient amount of renewable ammonia and methanol is only produced by adding a price premium of about 50% (0.16 e/kg) to the conventional fuel prices. To utilize production efficiently on-site renewable energy sources and P2X must be carefully aligned. We show that renewable power purchase agreements can provide flexibility while complying with the rules set by the European Commission.
A Review of The Methanol Economy: The Fuel Cell Route
Jan 2020
Publication
This review presents methanol as a potential renewable alternative to fossil fuels in the fight against climate change. It explores the renewable ways of obtaining methanol and its use in efficient energy systems for a net zero-emission carbon cycle with a special focus on fuel cells. It investigates the different parts of the carbon cycle from a methanol and fuel cell perspective. In recent years the potential for a methanol economy has been shown and there has been significant technological advancement of its renewable production and utilization. Even though its full adoption will require further development it can be produced from renewable electricity and biomass or CO2 capture and can be used in several industrial sectors which make it an excellent liquid electrofuel for the transition to a sustainable economy. By converting CO2 into liquid fuels the harmful effects of CO2 emissions from existing industries that still rely on fossil fuels are reduced. The methanol can then be used both in the energy sector and the chemical industry and become an all-around substitute for petroleum. The scope of this review is to put together the different aspects of methanol as an energy carrier of the future with particular focus on its renewable production and its use in high-temperature polymer electrolyte fuel cells (HT-PEMFCs) via methanol steam reforming.
Materials for Hydrogen-based Energy Storage - Past, Recent Progress and Future Outlook
Dec 2019
Publication
Michael Hirscher,
Volodymyr A. Yartys,
Marcello Baricco,
José Bellosta von Colbe,
Didier Blanchard,
Robert C. Bowman Jr.,
Darren P. Broom,
Craig Buckley,
Fei Chang,
Ping Chen,
Young Whan Cho,
Jean-Claude Crivello,
Fermin Cuevas,
William I. F. David,
Petra E. de Jongh,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
Yaroslav Filinchuk,
George E. Froudakis,
David M. Grant,
Evan MacA. Gray,
BjĂžrn Christian Hauback,
Teng He,
Terry D. Humphries,
Torben R. Jensen,
Sangryun Kim,
Yoshitsugu Kojima,
Michel Latroche,
Hai-wen Li,
Mykhaylo V. Lototskyy,
Joshua W. Makepeace,
Kasper T. MĂžller,
Lubna Naheed,
Peter Ngene,
Dag Noreus,
Magnus Moe NygÄrd,
Shin-ichi Orimo,
Mark Paskevicius,
Luca Pasquini,
Dorthe B. RavnsbĂŠk,
M. Veronica Sofianos,
Terrence J. Udovic,
Tejs Vegge,
Gavin Walker,
Colin Webb,
Claudia Weidenthaler and
Claudia Zlotea
Globally the accelerating use of renewable energy sources enabled by increased efficiencies and reduced costs and driven by the need to mitigate the effects of climate change has significantly increased research in the areas of renewable energy production storage distribution and end-use. Central to this discussion is the use of hydrogen as a clean efficient energy vector for energy storage. This review by experts of Task 32 âHydrogen-based Energy Storageâ of the International Energy Agency Hydrogen TCP reports on the development over the last 6 years of hydrogen storage materials methods and techniques including electrochemical and thermal storage systems. An overview is given on the background to the various methods the current state of development and the future prospects. The following areas are covered; porous materials liquid hydrogen carriers complex hydrides intermetallic hydrides electro-chemical storage of energy thermal energy storage hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage
Life Cycle Assessment Integration into Energy System Models: An Application for Power-to-Methane in the EU
Nov 2019
Publication
As the EU energy system transitions to low carbon the technology choices should consider a broader set of criteria. The use of Life Cycle Assessment (LCA) prevents burden shift across life cycle stages or impact categories while the use of Energy System Models (ESM) allows evaluating alternative policies capacity evolution and covering all the sectors. This study does an ex-post LCA analysis of results from JRC-EU-TIMES and estimates the environmental impact indicators across 18 categories in scenarios that achieve 80â95% CO2Â emission reduction by 2050. Results indicate that indirect CO2Â emissions can be as large as direct ones for an 80% CO2Â reduction target and up to three times as large for 95% CO2Â reduction. Impact across most categories decreases by 20â40% as the CO2Â emission target becomes stricter. However toxicity related impacts can become 35â100% higher. The integrated framework was also used to evaluate the Power-to-Methane (PtM) system to relate the electricity mix and various CO2 sources to the PtM environmental impact. To be more attractive than natural gas the climate change impact of the electricity used for PtM should be 123â181 gCO2eq/kWh when the CO2Â comes from air or biogenic sources and 4â62 gCO2eq/kWh if the CO2 is from fossil fuels. PtM can have an impact up to 10 times larger for impact categories other than climate change. A system without PtM results in ~4% higher climate change impact and 9% higher fossil depletion while having 5â15% lower impact for most of the other categories. This is based on a scenario where 9 parameters favor PtM deployment and establishes the upper bound of the environmental impact PtM can have. Further studies should work towards integrating LCA feedback into ESM and standardizing the methodology.
The Role of Electrification and Hydrogen in Breaking the Biomass Bottleneck of the Renewable Energy System â A Study on the Danish Energy System
Jun 2020
Publication
The aim of this study is to identify the technical solution space for future fully renewable energy systems that stays within a sustainable biomass demand. In the transition towards non-fossil energy and material systems biomass is an attractive source of carbon for those demands that also in the non-fossil systems depend on high density carbon containing fuels and feedstocks. However extensive land use is already a sustainability challenge and an increase in future demands threat to exceed global sustainable biomass potentials which according to an international expert consensus is around 10 â 30 GJ/person/year in 2050. Our analytical review of 16 scenarios from 8 independent studies of fully renewable energy system designs and synthesis of 9 generic system designs reveals the significance of the role of electrification and hydrogen integration for building a fully renewable energy system which respects the global biomass limitations. The biomass demand of different fully renewable energy system designs was found to lie in the range of 0 GJ/person/year for highly integrated electrified pure electro-fuel scenarios with up to 25 GJ/person/year of hydrogen to above 200 GJ/person/year for poorly integrated full bioenergy scenarios with no electrification or hydrogen integration. It was found that a high degree of system electrification and hydrogen integration of at least 15 GJ/person/year is required to stay within sustainable biomass limits.
Hubs and Clusters Approach to Unlock the Development of Carbon Capture and Storage - Case Study in Spain
Jul 2021
Publication
Xiaolong Sun,
Juan Alcalde,
Mahdi Bakhtbidar,
Javier ElĂo,
VĂctor Vilarrasa,
Jacobo Canal,
Julio Ballesteros,
Niklas Heinemann,
Stuart Haszeldine,
Andrew Cavanagh,
David Vega-Maza,
Fernando Rubiera,
Roberto MartĂnez-Orio,
Gareth Johnson,
Ramon Carbonell,
Ignacio Marzan,
Anna Travé and
Enrique Gomez-Rivas
Many countries have assigned an indispensable role for carbon capture and storage (CCS) in their national climate change mitigation pathways. However CCS deployment has stalled in most countries with only limited commercial projects realised mainly in hydrocarbon-rich countries for enhanced oil recovery. If the Paris Agreement is to be met then this progress must be replicated widely including hydrocarbon-limited countries. In this study we present a novel source-to-sink assessment methodology based on a hubs and clusters approach to identify favourable regions for CCS deployment and attract renewed public and political interest in viable deployment pathways. Here we apply this methodology to Spain where fifteen emission hubs from both the power and the hard-to-abate industrial sectors are identified as potential CO2 sources. A priority storage structure and two reserves for each hub are selected based on screening and ranking processes using a multi-criteria decision-making method. The priority source-to-sink clusters are identified indicating four potential development regions with the North-Western and North-Eastern Spain recognised as priority regions due to resilience provided by different types of CO2 sources and geological structures. Up to 68.7 Mt CO2 per year comprising around 21% of Spanish emissions can be connected to clusters linked to feasible storage. CCS especially in the hard-to-abate sector and in combination with other low-carbon energies (e.g. blue hydrogen and bioenergy) remains a significant and unavoidable contributor to the Paris Agreementâs mid-century net-zero target. This study shows that the hubs and clusters approach can facilitate CCS deployment in Spain and other hydrocarbon-limited countries.
A Novel Scheme to Allocate the Green Energy Transportation CostsâApplication to Carbon Captured and Hydrogen
Mar 2023
Publication
Carbon dioxide (CO2 ) and hydrogen (H2 ) are essential energy vectors in the green energy transition. H2 is a fuel produced by electrolysis and is applied in heavy transportation where electrification is not feasible yet. The pollutant substance CO2 is starting to be captured and stored in different European locations. In Denmark the energy vision aims to use this CO2 to be reacted with H2 producing green methanol. Typically the production units are not co-located with consumers and thus the required transportation infrastructure is essential for meeting supply and demand. This work presents a novel scheme to allocate the transportation costs of CO2 and H2 in pipeline networks which can be applied to any network topology and with any allocation method. During the tariff formation process coordinated adjustments are made by the novel scheme on the original tariffs produced by the allocation method employed considering the location of each customer connected to pipeline network. Locational tariffs are provided as result and the total revenue recovery is guaranteed to the network owner. Considering active customers the novel scheme will lead to a decrease of distant pipeline flows thereby contributing to the prevention of bottlenecks in the transportation network. Thus structural reinforcements can be avoided reducing the total transportation cost paid by all customers in the long-term.
Potential Role of Renewable Gas in the Transition of Electricity and District Heating Systems
Dec 2019
Publication
With the constant increase in variable renewable energy production in electricity and district heating systems integration with the gas system is a way to provide flexibility to the overall energy system. In the sustainable transition towards a zero-emission energy system traditional natural gas can be substituted by renewable gasses derived from anaerobic digestion or thermal gasification and hydrogen. In this paper we present a methodology for modelling renewable gas options and limits on biomass resources across sectors in the energy optimisation model Balmorel. Different scenarios for socio-economic pathways to emission neutral electricity and district heating systems in Denmark Sweden Norway and Germany show that a renewable based energy system benefits from a certain percentage of gas as a supplement to other flexibility options like interconnectors. Especially upgraded biogas from anaerobic digestion serves as a substitute for natural gas in all scenarios. Allocating only 10% of available biomass to the electricity and district heating sector leads to full exploitation of the scarce biomass resource by boosting biogas and syngas with hydrogen. The need for renewable gasses is highest in Germany and least in Norway where hydro-power provides flexibility in terms of storable and dispatchable electricity production. The scenarios show that a required ââlate sprint" from fossils to achieve a zero-emission energy system in 2050 causes (1) significant higher accumulated emissions and (2) a system which strongly relies on fuels also in an emission free system instead of stronger integration of the electricity and district heating systems through electrification as well as stronger integration of the power systems across countries through interconnectors.
Low-carbon and Cost-efficient Hydrogen Optimisation through a Grid-connected Electrolyser: The Case of GreenLab Skive
Nov 2022
Publication
Power-to-X technologies are a promising means to achieve Denmarkâs carbon emission reduction targets. Water electrolysis can potentially generate carbon-neutral fuels if powered with renewable electricity. However the high variability of renewable sources threatens the Power-to-X plantâs cost-efficiency instead favouring high and constant operation rates. Therefore a diversified electricity supply is often an option to maximise the load factor of the Power-to-X systems. This paper analyses the impact of using different power sources on the cost of production and the carbon intensity of hydrogen produced by a Power-to-X system. GreenLab Skive the worldâs first industrial facility with Power-to-X integrated into an industrial symbiosis network has been used as a case study. Results show that the wind/PV/grid-connected electrolyser for hydrogen and electricity production can reduce operational costs and emissions saving 30.6 Ă 107 kgCO2 and having a Net Present Value twice higher than a grid-connected electrolyser. In addition the carbon emission coefficient for this configuration is 3.5 Ă 10â 2 kgH2/kgCO2 against 7.0 gH2/gCO2 produced by Steam Methane Reforming. A sensitivity analysis detects the optimal capacity ratio between the renewables and the electrolyser. A plateau is reached for carbon emission performances suggesting a wind/grid-connected electrolyser setup with a wind farm three times the size of the electrolyser. Results demonstrate that hydrogen cost is not competitive yet with the electricity suggesting an investment cost reduction but can be competitive with the current hydrogen price if the wind capacity is less than three times the electrolyser capacity.
Review of Energy Portfolio Optimization in Energy Markets Considering Flexibility of Power-to-X
Mar 2023
Publication
Power-to-X is one of the most attention-grabbing topics in the energy sector. Researchers are exploring the potential of harnessing power from renewable technologies and converting it into fuels used in various industries and the transportation sector. With the current market and research emphasis on Power-to-X and the accompanying substantial investments a review of Power-to-X is becoming essential. Optimization will be a crucial aspect of managing an energy portfolio that includes Power-to-X and electrolysis systems as the electrolyzer can participate in multiple markets. Based on the current literature and published reviews none of them adequately showcase the state-of-the-art optimization algorithms for energy portfolios focusing on Power-to-X. Therefore this paper provides an in-depth review of the optimization algorithms applied to energy portfolios with a specific emphasis on Power-to-X aiming to uncover the current state-of-the-art in the field.
Source-to-sink Efficiency of Blue and Green District Heating and Hydrogen-based Heat Supply Systems
Apr 2022
Publication
Hydrogen is commonly mentioned as a future proof energy carrier. Hydrogen supporters 6 advocate for repurposing existing natural gas grids for a sustainable hydrogen supply. While the 7 long-term vision of the hydrogen community is green hydrogen the community acknowledges that 8 in the short term it will be to large extent manufactured from natural gas but in a decarbonized 9 way giving it the name blue hydrogen. While hydrogen has a role to play in hard to decarbonize 10 sectors its role for building heating demands is doubtful as mature and more energy efficient alter- 11 natives exist. As building heat supply infrastructures built today will operate for the decades to 12 come it is of highest importance to ensure that the most efficient and sustainable infrastructures are 13 chosen. This paper compares the source to sink efficiencies of hydrogen-based heat supply system 14 to a district heating system operating on the same primary energy source. The results show that a 15 natural gas-based district heating could be 267% more efficient and consequently have significantly 16 lower global warming potential than a blue hydrogen-based heat supply A renewable power-based 17 district heating could achieve above 440% higher efficiency than green hydrogen-based heat supply 18 system.
Safety and Other Considerations in the Development of a Hydrogen Fueling Protocol for Heavy-duty Vehicles
Sep 2021
Publication
Several manufacturers are developing heavy duty (HD) hydrogen stations and vehicles as zeroemissions alternatives to diesel and gasoline. In order to meet customer demands the new technology must be comparable to conventional approaches including safety reliability fueling times and final fill levels. For a large HD vehicle with a storage rated to 70 MPa nominal working pressure the goal to meet liquid fuel parity means providing 100 kg of hydrogen in 10 minutes. This paper summarizes the results to date of the PRHYDE project efforts to define the concepts of HD fueling which thereby lays the groundwork for the development of the safe and effective approach to filling these large vehicles. The project starts by evaluating the impact of several different assumptions such as the availability of static vehicle data (e.g. vehicle tank type and volume) and station data (e.g. expected station precooling capability) but also considers using real time dynamic data (e.g. vehicle tank gas temperature and pressure station gas temperature etc.) for optimisation to achieve safety and efficiency improvements. With this information the vehicle or station can develop multiple maps of fill time versus the hydrogen delivery temperature which are used to determine the speed of fueling. This will also allow the station or vehicle to adjust the rate of fueling as the station pre-cooling levels and other conditions change. The project also examines different steps for future protocol development such as communication of data between the vehicle and station and if the vehicle or station is controlling the fueling.
NewGasMet - Â Flow Metering of Renewable Gases (Biogas, Biomethane, Hydrogen, Syngas and Mixtures with Natural Gas): Report on the Usable Technologies for Calibrating Gas Meters with Renewable Gases and Currently Available Flow Standards Suitable for Use with Methane, Crude Biogas, Hydrogen and Mixtures of these gases
Mar 2021
Publication
The main goal stated at the Paris agreement is to limit the global temperature rise well below 2 °C above pre-industrial levels. Limiting the increase of global average temperature to 1.5 °C is striven since risks and impacts of the climate change would be reduced drastically. To face these challenges the European Green Deal was invented by the European Commission. The âGreen Dealâ is a growth strategy which aims to transform the economy of the EU into a resource-efficient modern and competitive one [1-1 1-2]. Figure 1: The key elements of the European Green Deal [1-2] In this context the European Commission proposed that the amount of renewable energy within the EUâs overall energy mix should reach 20 % by 2020 and therefore producing energy by solar and wind plants become even more important. For example the cumulative installed wind farm capacity increased from 117.3 GW in 2013 to a total capacity of 182.163 GW in 2018 within the EU [1-4-1-6]. Due to the fluctuations in energy produced by wind farms storage of electricity is crucial. One possibility for storage is the production of hydrogen via electrolysis using renewable energy sources like wind farms. The hydrogen is then either directly added to the gas distribution grid or is converted to methane with external CO or CO2 which is then added to the gas distribution grid as a substitute [1-4]. Increasing the knowledge about the impact of renewable gases on available gas meters in terms of accuracy and durability is the main object of the EMPIR NEWGASMET project. Therefore in activity A3.1.1 a literature study was performed to provide information on which technologies can be used to calibrate gas meters when using renewable gases.
A Review of the MSCA ITN ECOSTOREâNovel Complex Metal Hydrides for Efficient and Compact Storage of Renewable Energy as Hydrogen and Electricity
Mar 2020
Publication
Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+ Mg2+ and Ca2+ while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie SkĆodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed.
Hydrogen Deep Ocean Link: A Global Sustainable Interconnected Energy Grid
Mar 2022
Publication
The world is undergoing a substantial energy transition with an increasing share of intermittent sources of energy on the grid which is increasing the challenges to operate the power grid reliably. An option that has been receiving much focus after the COVID pandemic is the development of a hydrogen economy. Challenges for a hydrogen economy are the high investment costs involved in compression storage and long-distance transportation. This paper analyses an innovative proposal for the creation of hydrogen ocean links. It intends to fill existing gaps in the creation of a hydrogen economy with the increase in flexibility and viability for hydrogen production consumption compression storage and transportation. The main concept behind the proposals presented in this paper consists of using the fact that the pressure in the deep sea is very high which allows a thin and cheap HDPE tank to store and transport large amounts of pressurized hydrogen in the deep sea. This is performed by replacing seawater with pressurized hydrogen and maintaining the pressure in the pipes similar to the outside pressure. Hydrogen Deep Ocean Link has the potential of increasing the interconnectivity of different regional energy grids into a global sustainable interconnected energy system.
NewGasMet - Â Flow Metering of Renewable Gases (Biogas, Biomethane, Hydrogen, Syngas and Mixtures with Natural Gas): Criteria and Proposals for EMC Tests on Ultrasonic Meters with Non-conventional Gases
Oct 2022
Publication
The NEWGASMET project has the overall objective to increase knowledge about the accuracy and durability of commercially available gas meters after exposure to renewable gases. This should lead to the improvement of existing meter designs and flow calibration standards. One of the recently released results is a proposal for a set of test gases to represent the range of non-conventional gases in the scope of the revision of the gas meter standards. In details these were proposed to be used in the CEN/TC237 standards and the OIML-R137:2014. During the project meetings concerns have been raised regarding the applicability of such test gases to EMC tests for static meters. Today such tests are performed in air but there is a clear agreement that the behaviour of the meter during EMC tests can be influenced by the renewable gas type. At least this agreement exists for the ultrasonic measurement technology while further discussion might be needed for the mass flow. However it is not simply possible to redesign the current EMC tests by replacing air with the defined gas mixtures as this would be quite impractical especially considering the explosive nature of the test gases.
From Renewable Energy to Sustainable Protein Sources: Advancement, Challenges, and Future Roadmaps
Jan 2022
Publication
The concerns over food security and protein scarcity driven by population increase and higher standards of living have pushed scientists toward finding new protein sources. A considerable proportion of resources and agricultural lands are currently dedicated to proteinaceous feed production to raise livestock and poultry for human consumption. The 1st generation of microbial protein (MP) came into the market as land-independent proteinaceous feed for livestock and aquaculture. However MP may be a less sustainable alternative to conventional feeds such as soybean meal and fishmeal because this technology currently requires natural gas and synthetic chemicals. These challenges have directed researchers toward the production of 2nd generation MP by integrating renewable energies anaerobic digestion nutrient recovery biogas cleaning and upgrading carbon-capture technologies and fermentation. The fermentation of methane-oxidizing bacteria (MOB) and hydrogen-oxidizing bacteria (HOB) i.e. two protein rich microorganisms has shown a great potential on the one hand to upcycle effluents from anaerobic digestion into protein rich biomass and on the other hand to be coupled to renewable energy systems under the concept of Power-to-X. This work compares various production routes for 2nd generation MP by reviewing the latest studies conducted in this context and introducing the state-of-the-art technologies hoping that the findings can accelerate and facilitate upscaling of MP production. The results show that 2nd generation MP depends on the expansion of renewable energies. In countries with high penetration of renewable electricity such as Nordic countries off-peak surplus electricity can be used within MP-industry by supplying electrolytic H2 which is the driving factor for both MOB and HOB-based MP production. However nutrient recovery technologies are the heart of the 2nd generation MP industry as they determine the process costs and quality of the final product. Although huge attempts have been made to date in this context some bottlenecks such as immature nutrient recovery technologies less efficient fermenters with insufficient gas-to-liquid transfer and costly electrolytic hydrogen production and storage have hindered the scale up of MP production. Furthermore further research into techno-economic feasibility and life cycle assessment (LCA) of coupled technologies is still needed to identify key points for improvement and thereby secure a sustainable production system.
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