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Experimental Aspects of the Hydrogen Use at Diesel Engine
May 2017
Publication
In the global content regarding the impact on the environmental of the gases emissions resulted from the fossil fuels combustion aspect discussed on the 2015 Paris Climate Conference contribute to the necessity of searching of alternative energy from durable and renewable resources. The purpose of the paper is the use of hydrogen fuelling at truck diesel engine in order to improves engine efficiency and pollutant performance hydrogen being injected into the inlet manifold. Experimental results show better energetic and pollution performance of the dual fuelled engine due to the improvement of the combustion process and reduction of carbon content.
Hazard Footprint of Alternative Fuel Storage Concepts for Hydrogen-powered Urban Buses
Nov 2023
Publication
Hydrogen mobility is a powerful strategy to fight climate change promoting the decarbonization of the transportation sector. However the higher flammability of hydrogen in comparison with traditional fuels raises issues concerning the safety of hydrogen-powered vehicles in particular when urban mobility in crowded areas is concerned. In the present study a comparative analysis of alternative hydrogen storage concepts for buses is carried out. A specific inherent safety assessment methodology providing a hazard footprint of alternative hydrogen storage technologies was developed. The approach provides a set of ex-ante safety performance indicators and integrates a sensitivity analysis performed by a Monte Carlo method. Integral models for consequence analysis and a set of baseline frequencies are used to provide a preliminary identification of the worstcase credible fire and explosion scenarios and to rank the inherent safety of alternative concepts. Cryocompressed storage in the supercritical phase resulted as the more hazardous storage concept while cryogenic storage in the liquid phase at ambient pressure scored the highest safety performance. The results obtained support risk-informed decision-making in the shift towards the promotion of sustainable mobility in urban areas.
The Potential of Hydrogen-battery Storage Systems for a Sustainable Renewable-based Electrification of Remote Islands in Norway
Oct 2023
Publication
Remote locations and off-grid regions still rely mainly on diesel generators despite the high operating costs and greenhouse gas emissions. The exploitation of local renewable energy sources (RES) in combination with energy storage technologies can be a promising solution for the sustainable electrification of these areas. The aim of this work is to investigate the potential for decarbonizing remote islands in Norway by installing RES-based energy systems with hydrogen-battery storage. A national scale assessment is presented: first Norwegian islands are characterized and classified according to geographical location number of inhabitants key services and current electrification system. Then 138 suitable installation sites are pinpointed through a multiple-step sorting procedure and finally 10 reference islands are identified as representative case studies. A site-specific methodology is applied to estimate the electrical load profiles of all the selected reference islands. An optimization framework is then developed to determine the optimal system configuration that minimizes the levelized cost of electricity (LCOE) while ensuring a reliable 100% renewable power supply. The LCOE of the RES-based energy systems range from 0.21 to 0.63 €/kWh and a clear linear correlation with the wind farm capacity factor is observed (R2 equal to 0.87). Hydrogen is found to be crucial to prevent the oversizing of the RES generators and batteries and ensure long-term storage capacity. The techno-economic feasibility of alternative electrification strategies is also investigated: the use of diesel generators is not economically viable (0.87–1.04 €/kWh) while the profitability of submarine cable connections is highly dependent on the cable length and the annual electricity consumption (0.14–1.47 €/kWh). Overall the cost-effectiveness of RES-based energy systems for off-grid locations in Northern Europe can be easily assessed using the correlations derived in this analysis.
Necessary and Sufficient Conditions for Deploying Hydrogen Homes: A Consumer-oriented Perspective
May 2024
Publication
As part of its efforts to secure a ‘net-zero society’ the UK government will take a strategic decision on the role of hydrogen in decarbonising homes within the next years. While scholars have recently advanced the social science research agenda on hydrogen technology acceptance studies are yet to engage with the prospective dynamics of adopting ‘hydrogen homes’. In response this study examines the perceived adoption potential of hydrogen heating and cooking technologies as evaluated through the eyes of consumer. Engaging with behavioural and market acceptance this research draws on data from a broadly nationally representative online survey to examine the influence of safety technological economic environmental and emotional factors on the domestic hydrogen transition in the UK context. The analysis follows a multi-stage empirical approach integrating findings from partial least squares structural equation and necessary condition analysis to crystallise insights on this emergent subject. At this juncture perceived adoption potential may hinge primarily on emotional environmental safety and to a lesser extent technological perspectives. However consumers have an expressed preference for hydrogen heating over hydrogen cooking with perceived boiler performance emerging as a necessary condition for enabling adoption potential. At the formative phase of the transition risks associated with energy insecurity and fuel poverty exceed concerns over purchasing and running costs. Nevertheless economic factors remain less critical during the pre-deployment phase of the innovation-decision process. Across the full sample simple slope analysis highlights the moderating effects of gender age and housing tenure. Moreover statistically significant differences from both a sufficiency- and necessity-based perspective are detected between male property owners aged 55+ and female mortgage owners 18–34 years old. By bridging the knowledge gap between social acceptance and adoption intention this contribution reinforces the need for consumer engagement in the hydrogen economy advocating for more fine-grained mixed-methods analyses of technology acceptance dynamics to support decarbonisation strategies.
Renewable-power-assisted Production of Hydrogen and Liquid Hydrocarbons from Natural Gas: Techno-economic Analysis
Jun 2022
Publication
The declining cost of renewable power has engendered growing interest in leveraging this power for the production of chemicals and synthetic fuels. Here renewable power is added to the gas-to-liquid (GTL) process through Fischer–Tropsch (FT) synthesis in order to increase process efficiency and reduce CO2 emissions. Accordingly two realistic configurations are considered which differ primarily in the syngas preparation step. In the first configuration solid oxide steam electrolysis cells (SOEC) in combination with an autothermal reformer (ATR) are used to produce synthesis gas with the right composition while in the second configuration an electrically-heated steam methane reformer (E-SMR) is utilized for syngas production. The results support the idea of adding power to the GTL process mainly by increased process efficiencies and reduced process emissions. Assuming renewable power is available the process emissions would be 200 and 400 gCO2 L1 syncrude for the first and second configurations respectively. Configuration 1 and 2 show 8 and 4 times less emission per liter syncrude produced respectively compared to a GTL plant without H2 addition with a process emission of 1570 gCO2 L1 syncrude. By studying the two designs based on FT production carbon efficiency and FT catalyst volume a better alternative is to add renewable power to the SOEC (configuration 1) rather than using it in an E-SMR (configuration 2). Given an electricity price of $100/MW h and natural gas price of 5 $ per GJ FT syncrude and H2 can be produced at a cost between $15/MW h and $16/MW h. These designs are considered to better utilize the available carbon resources and thus expedite the transition to a low-carbon economy
Conflicts Between Economic and Low-carbon Reorientation Processes: Insights from a Contextual Analysis of Evolving Company Strategies in the United Kingdrom Petrochemical Industry (1970-2021)
Jul 2022
Publication
To situate its low-carbon transition process in longer-term real-world business contexts this article makes a longitudinal analysis of the UK petrochemical industry focusing on changing economic and socio-political environments and company strategies in the last 50 years. Using the Triple Embeddedness Framework the paper identifies two parallel and conflicting reorientation processes in the UK petrochemical industry. The first one which started in the 1970s and is driven by long-standing competitiveness problems led to retrenchment in the 1980s exit of incumbent companies (BP Shell ICI) and the entry of new firms (INEOS SABIC) in the 1990s and 2000s and diversification into upstream fossil fuel production and ethane imports in the 2010s. The second reorientation process which started in the 2010s is driven by climate change considerations and has led petrochemical firms to reluctantly explore low-carbon alternatives. Despite advancing ambitious visions and plans companies are weakly committed to low-carbon reorientation because this is layered on top of and conflicts with the deeper economically-motivated reorientation process. The paper further concludes that the industry's low-carbon plans and visions are partial because they focus more on some innovations (hydrogen-as-fuel CCS) than on other innovations (recycling bio-feedstocks synthetic feedstocks). Despite exploring alternatives firms also use political resistance strategies to hamper and delay deeper low-carbon reorientation
UK HSE Hydrogen for Heating Evidence Review Process
Sep 2023
Publication
As part of the UK Government’s Net Zero targets to tackle Climate Change the Health and Safety Executive (HSE) aims to reach an authoritative view on the safety of using 100% hydrogen for heating across the UK to feed into Government policy decisions by the mid-2020s. This paper describes the background and process of a programme of work led by HSE in support of the Department for Energy Security and Net Zero (formerly BEIS) that will inform strategic policy decisions by 2026. The strategic framework of HSE’s programme of work was defined between BEIS and HSE. HSE’s programme of work follows on from a previous project which engaged with HSE policy regulatory and scientific colleagues working with industry stakeholders identifying knowledge gaps for the safe distribution storage and use of hydrogen gas in domestic industrial and commercial premises. These knowledge gaps were subsequently used in discussions with stakeholders to prioritise research projects and evidence gathering exercises. To review this scientific evidence HSE developed a review framework and convened Evidence Review Groups (ERGs) to cover all evidence areas encompassing topics such as quantified risk assessment material compatibility and operational procedures. These ERGs include representation from relevant divisions across HSE (policy regulation and science). The paper explains the structure of HSE’s input into the hydrogen for heating programme the ERG process and timelines along with the proposed outputs. Additional activities have been undertaken by HSE within the programme to highlight specific issues in support of the review process which will also be discussed.
On-site Hydrogen Refuelling Station Techno-economic Model for a Fleet of Fuel Cell Buses
May 2024
Publication
Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation owing to various advantages such as reliability simplicity better energy efficiency and quietness of operation. However largescale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen is the cost of electricity for its production followed by transportation costs. On the one hand to reduce the investment cost of the electrolyzer high operating hours should be achieved; on the other as the number of operating hours decreases the impact of the electricity costs declines. This paper presents an innovative algorithm for a scalable hydrogen refuelling station (HRS) capable of successfully matching and identifying the most cost-efficient levelized cost of hydrogen (LCOH) produced via electrolysis and connected to the grid based on the HRS components’ cost curves and the hourly average electricity price profile. The objective is to identify the least-cost range of LCOH by considering both the electric energy and the investment costs associated with a hydrogen demand given by different FCB sizes and electrolyzer rated powers. In addition sensitivity analyses have been conducted to quantify the technology cost margins and a cost comparison between the refuelling of an FCB fleet and the recharging infrastructure required for an equivalent fleet of Battery Electric Buse (BEB) has been performed. An LCOH of around 10.5 €/kg varying from 12 €/kg (2 FCB) to 10.2 €/kg (30 FCB) has been found for the best-optimized configurations. The final major conclusion of this paper is that FCB technology is currently not economically competitive. Still a cost contraction of the electric energy price and the electrolyzer capital investment would lead to a 50% decrease in the LCOH. Furthermore increasing renewable energies into the grid may shift the electricity cost curve resulting in higher prices when the BEB recharging demand is more significant. This impact in addition to the peak power load and longer recharging times might contribute to bridging the gap with FCBs.
3D Modeling of the Different Boiling Regimes During Spill and Spreading of Liquid Hydrogen
Nov 2012
Publication
In a future energy generation market the storage of energy is going to become increasingly important. Besides classic ways of storage like pumped storage hydro power stations etc the production of hydrogen will play an important role as an energy storage system. Hydrogen may be stored as a liquefied gas (LH2) on a long term base as well as for short term supply of fuel stations to ensure a so called “green” mobility. The handling with LH2 has been subject to several recent safety studies. In this context reliable simulation tools are necessary to predict the spill and spreading of LH2 during an accidental release. This paper deals with the different boiling regimes: film boiling transition boiling and nucleation boiling after a release and their modeling by means of an inhouse-code for wall evaporation which is implemented in the commercial CFD code ANSYS CFX. The paper will describe the model its implementation and validation against experimental data such as the HSL LH2 spill experiments.
Are Green and Blue Hydrogen Competitive or Complementary? Insights from a Decarbonised European Power System Analysis
Jun 2023
Publication
Hydrogen will be important in decarbonized energy systems. The primary ways to produce low emission hydrogen are from renewable electricity using electrolyzers called green hydrogen and by reforming natural gas and capturing and storing the CO2 known as blue hydrogen. In this study the degrees to which blue and green hydrogen are complementary or competitive are analyzed through a sensitivity analysis on the electrolyzer costs and natural gas price. This analysis is performed on four bases: what is the cost-effective relative share between blue and green hydrogen deployment how their deployment influences the price of hydrogen how the price of CO2 changes with the deployment of these two technologies and whether infrastructure can economically be shared between these two technologies. The results show that the choice of green and blue hydrogen has a tremendous impact where an early deployment of green leads to higher hydrogen costs and CO2 prices in 2030. Allowing for blue hydrogen thus has notable benefits in 2030 giving cheaper hydrogen with smaller wider socioeconomic impacts. In the long term these competitive aspects disappear and green and blue hydrogen can coexist in the European market without negatively influencing one another.
Hydrogen Refueling Stations Powered by Hybrid PV/Wind Renewable Energy Systems: Techno-socio-economic Assessment
Mar 2024
Publication
Hydrogen is considered as an attractive alternative to fossil fuels in the transportation sector. However the penetration of Fuel Cell Electric Vehicles (FCEV) is hindered by the lack of hydrogen refueling station infrastructures. In this study the feasibility of a hybrid PV/wind system for hydrogen refueling station is investigated. Refueling events data is collected in different locations including industrial residential highway and tourist areas. Station Occupancy Fractions (SOF) and Social-to-Solar Fraction (STSF) indicators are developed to assess the level of synchronization between the hydrogen demand and solar potential. Then a validated computer code is used to optimize the renewable system components for off/on-grid cases based on minimizing the Net Present Cost (NPC) and the Loss of Hydrogen Supply Probability (LHSP). For off grid cases the results show that STSF attains maximum value in the industrial area where 0.62 fraction of refueling events occur during the sunshine hours and minimum NPC is achieved. It is observed that when STSF attains lower values of 0.52 0.41 and 0.38 for residential highway and tourist areas NPC increases by 8 16 and 31% respectively. This is associated with lower level of coordination between the hydrogen demand and solar potential. The same conclusion can be stated for the on-grid cases. Therefore for green hydrogen production via solar energy utilization it is recommended that a tariff should be applied to encourage refueling hydrogen vehicles during the availability of solar radiation while reducing the environmental impact storage requirements and eventually the cost of hydrogen production.
Synergy-based Hydrogen Pricing in Hydrogen-Integrated Electric Power System: Sensititivy Analysis
Nov 2024
Publication
Hydrogen price significantly impacts its potential as a viable alternative in the sustainable energy transition. This study introduces a synergy-based Hydrogen Pricing Mechanism (HPM) within an integrated framework. The HPM leverages synergy between a Renewable-Penetrated Electric Power System (RP-EPS) and a Hydrogen Energy System (HES). Utilizing the Alternating Direction Method of Multipliers (ADMM) it facilitates data exchange quantifying integration levels and simplifying the complexities. The study assesses the HPM’s operational sensitivity across various scenarios of hydrogen generation transportation and storage. It also evaluates the benefits of synergy-based versus stand-alone HPMs. Findings indicate that the synergy-based HPM effectively integrates infrastructure and operational improvements from both EPS and HES leading to optimized hydrogen pricing.
Explosion Free in Fire Self-venting (TPRD-less) Composite Tanks: Performance Under Fire Intervention Conditions
Sep 2023
Publication
This paper describes the performance of explosion free in fire self-venting (TPRD-less) composite tanks of Type IV in fires of realistic intensity HRR/A=1 MW/m2 in conditions of first responders’ intervention. This breakthrough safety technology does not require the use of thermally activated pressure relief devices (TPRD). It provides microleaks-no-burst (LNB) performance of high-pressure hydrogen storage tanks in a fire. Two fire intervention strategies are investigated one is the removal of a vehicle with LNB tank from the fire and another is the extinction of the fire. The removal from the fire scenario is investigated for one carbon-carbon and one carbon-basalt double-composite wall tank prototype. The fire extinction scenario is studied for four carbon-basalt prototypes. All six prototypes of 7.5 L volume and nominal working pressure of 70 MPa demonstrated safe release of hydrogen through microchannels of the composite wall after melting a liner. The technology allows fire brigades to apply standard intervention strategies and tactics at the fire scene with hydrogen vehicles if LNB tanks are used in the vehicle.
Methods for Enhancing Electrolysis for Hydrogen Production: The Benefits of Applying Magnetic Fields
Sep 2024
Publication
The electrolysis of water is one of the most promising ways of producing green hydrogen. This produces hydrogen using electricity and does not generate additional carbon dioxide like the more conventional reforming of fossil fuels. However making electrolysis competitive with conventional methods for hydrogen production is a challenge because of the cost of electricity and because of inefficiencies and costs in electrolysis systems. Initially this review looks at the basic design of water electrolysis and asks where energy is lost. Then a selection of the latest results in the area of magnetic field-enhanced water electrolysis are examined and discussed in particular focusing on the empirical results of magnetic field-assisted electrolysis with the aim of comparing findings and identifying limitations of current studies such that recommendations can be made for advanced design of hydrogen producing electrolysis systems.
Review of Common Hydrogen Storage Tanks and Current Manufacturing Methods for Aluminium Tank Liners
Aug 2023
Publication
With the growing concern about climate issues and the urgent need to reduce carbon emissions hydrogen has attracted increasing attention as a clean and renewable vehicle energy source. However the storage of flammable hydrogen gas is a major challenge and it restricts the commercialisation of fuel cell electric vehicles (FCEVs). This paper provides a comprehensive review of common on-board hydrogen storage tanks possible failure mechanisms and typical manufacturing methods as well as their future development trends. There are generally five types of hydrogen tanks according to different materials used with only Type III (metallic liner wrapped with composite) and Type IV (polymeric liner wrapped with composite) tanks being used for vehicles. The metallic liner of Type III tank is generally made from aluminium alloys and the associated common manufacturing methods such as roll forming deep drawing and ironing and backward extrusion are reviewed and compared. In particular backward extrusion is a method that can produce near net-shape cylindrical liners without the requirement of welding and its tool designs and the microstructural evolution of aluminium alloys during the process are analysed. With the improvement and innovation on extrusion tool designs the extrusion force which is one of the most demanding issues in the process can be reduced significantly. As a result larger liners can be produced using currently available equipment at a lower cost.
Identification of Safety Critical Scenarios of Hydrogen Refueling Stations in a Multifuel Context
Sep 2023
Publication
The MultHyFuel Project funded by the Clean Hydrogen Partnership aims to achieve the effective and safe deployment of hydrogen as a carbon-neutral fuel by developing a common strategy for implementing Hydrogen Refueling Stations (HRS) in a multifuel context. The project hopes to contribute to the harmonisation of existing regulations codes and standards (RCS) by generating practical theoretical and experimental data related to HRS.<br/>This paper presents how a set of safety critical scenarios have been identified from the initial preliminary as well as detailed risk analysis of three different hydrogen refueling station configurations. To achieve this a detailed examination of each potential hazardous phenomenon (DPh) or major accident event at or near the hydrogen dispenser was carried out. Particular attention is paid to the scenarios which could affect third parties external to the refueling station.<br/>The paper presents a methodology subdivided into the following steps:<br/>♦ determination of the consequence level and likelihood of each hazardous phenomenon<br/>♦ the classification of major hazard scenarios for the 3 HRS configurations specifically those arising on the dispensing forecourt;<br/>♦ proposal of example preventative control and/or mitigation barriers that could potentially reduce the probability of occurrence and/ or consequences of safety critical scenarios and hence reducing risks to a tolerable level or to as low as reasonably practicable.
An Overview of Hydrogen Storage Technologies - Key Challenges and Opportunities
Jul 2024
Publication
Hydrogen energy has been proposed as a reliable and sustainable source of energy which could play an integral part in demand for foreseeable environmentally friendly energy. Biomass fossil fuels waste products and clean energy sources like solar and wind power can all be employed for producing hydrogen. This comprehensive review paper provides a thorough overview of various hydrogen storage technologies available today along with the benefits and drawbacks of each technology in context with storage capacity efficiency safety and cost. Since safety concerns are among the major barriers to the broad application of H2 as a fuel source special attention has been paid to the safety implications of various H2 storage techniques. In addition this paper highlights the key challenges and opportunities facing the development and commercialization of hydrogen storage technologies including the need for improved materials enhanced system integration increased awareness and acceptance. Finally recommendations for future research and development with a particular focus on advancing these technologies towards commercial viability.
How "Clean" is the Hydrogen Economy? Tracing the Connections Between Hydrogen and Fossil Fuels
Feb 2024
Publication
Hydrogen is experiencing a resurgence in energy transition debates. Before representing a solution however the existing hydrogen economy is still a climate change headache: over 99 % of production depends on fossil fuels oil refining accounts for 42 % of demand and its transportation is intertwined with fossil infrastructure like natural gas pipelines. This article investigates the path-dependent dynamics shaping the hydrogen economy and its interconnections with the oil and gas industry. It draws on the global production networks (GPN) approach and political economy research to provide a comprehensive review of current and prospective enduses of hydrogen modes of transport networks of industrial actors and state strategies along the major production facilities and holders of intellectual property rights. The results presented in this article suggest that the superimposition of private agendas may jeopardise the viability of future energy systems and requires counterbalancing forces to override the negative consequences of path-dependent energy transitions.
Repurposing Natural Gas Pipelines for Hydrogen: Limits and Options from a Case Study in Germany
Jul 2024
Publication
We investigate the challenges and options for repurposing existing natural gas pipelines for hydrogen transportation. Challenges of re-purposing are mainly related to safety and due to the risk of hydrogen embrittlement of pipeline steels and the smaller molecular size of the gas. From an economic perspective the lower volumetric energy density of hydrogen compared to natural gas is a challenge. We investigate three pipeline repurposing options in depth: a) no modification to the pipeline but enhanced maintenance b) use of gaseous inhibitors and c) the pipe-in-pipe approach. The levelized costs of transportation of these options are compared for the case of the German Norddeutsche Erdgasleitung (NEL) pipeline. We find a similar cost range for all three options. This indicates that other criteria such as the sunk costs public acceptance and consumer requirements are likely to shape the decision making for gas pipeline repurposing.
Near-term Infrastructure Rollout and Investment Strategies for Net-zero Hydrogen Supply Chains
Feb 2024
Publication
Low-carbon hydrogen plays a key role in European industrial decarbonization strategies. This work investigates the cost-optimal planning of European low-carbon hydrogen supply chains in the near term (2025–2035) comparing several hydrogen production technologies and considering multiple spatial scales. We focus on mature hydrogen production technologies: steam methane reforming of natural gas biomethane reforming biomass gasification and water electrolysis. The analysis includes carbon capture and storage for natural gas and biomass-derived hydrogen. We formulate and solve a linear optimization model that determines the costoptimal type size and location of hydrogen production and transport technologies in compliance with selected carbon emission targets including the EU fit for 55 target and an ambitious net-zero emissions target for 2035. Existing steam methane reforming capacities are considered and optimal carbon and biomass networks are designed. Findings identify biomass-based hydrogen production as the most cost-efficient hydrogen technology. Carbon capture and storage is installed to achieve net-zero carbon emissions while electrolysis remains costdisadvantageous and is deployed on a limited scale across all considered sensitivity scenarios. Our analysis highlights the importance of spatial resolution revealing that national perspectives underestimate costs by neglecting domestic transport needs and regional resource constraints emphasizing the necessity for highly decarbonized infrastructure designs aligned with renewable resource availabilities.
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