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On the Green Transformation of the Iron and Steel Industry: Market and Competition Aspects of Hydrogen Biomass Options
Feb 2024
Publication
The iron and steel industry is a major emitter of carbon dioxide globally. To reduce their carbon footprint the iron and steel industry pursue different decarbonization strategies including deploying bio-based materials and energy carriers for reduction carburisation and/or energy purposes along their value-chains. In this study two potential roles for biomass were analysed: (a) substituting for fossil fuels in iron-ore pellets induration and (b) carburisation of DRI (direct reduced iron) produced via fully hydrogen-based reduction. The purpose of the study was to analyse the regional demand-driven price and allocative effects of biomass assortments under different biomass demand scenarios for the Swedish iron and steel industry. Economic modelling was used in combination with spatial biomass supply assessments to predict the changes on relevant biomass markets. The results showed that the estimated demand increases for forest biomass will have significant regional price effects. Depending on scenario the biomass demand will increase up to 25 percent causing regional prices to more than doubling. In general the magnitude of the price effects was driven by the volumes and types of biomasses needed in the different scenarios with larger price effects for harvesting residues and industrial by-products compared to those of roundwood. A small price effect of roundwood means that the incentives for forest-owners to increase their harvests and thus also the availability of harvest residues are small. Flexibility in the feedstock sourcing (both regarding quality and geographic origin) will thus be important if forest biomass is to satisfy demands in iron and steel industry.
Advancing Hydrogen: A Closer Look at Implementation Factors, Current Status and Future Potential
Dec 2023
Publication
This review article provides a comprehensive analysis of the hydrogen landscape outlining the imperative for enhanced hydrogen production implementation and utilisation. It places the question of how to accelerate hydrogen adoption within the broader context of sustainable energy transitions and international commitments to reduce carbon emissions. It discusses influencing factors and policies for best practices in hydrogen energy application. Through an in-depth exploration of key factors affecting hydrogen implementation this study provides insights into the complex interplay of both technical and logistical factors. It also discusses the challenges of planning constructing infrastructure and overcoming geographical constraints in the transition to hydrogen-based energy systems. The drive to achieve net-zero carbon emissions is contingent on accelerating clean hydrogen development with blue and green hydrogen poised to complement traditional fuels. Public–private partnerships are emerging as catalysts for the commercialisation of hydrogen and fuel-cell technologies fostering hydrogen demonstration projects worldwide. The anticipated integration of clean hydrogen into various sectors in the coming years signifies its importance as a complementary energy source although specific applications across industries remain undefined. The paper provides a good reference on the gradual integration of hydrogen into the energy landscape marking a significant step forward toward a cleaner greener future.
Hydrogen Storage as a Key Energy Vector for Car Transportation: A Tutorial Review
Oct 2023
Publication
Hydrogen storage is a key enabling technology for the extensive use of hydrogen as energy carrier. This is particularly true in the widespread introduction of hydrogen in car transportation. Indeed one of the greatest technological barriers for such development is an efficient and safe storage method. So in this tutorial review the existing hydrogen storage technologies are described with a special emphasis on hydrogen storage in hydrogen cars: the current and the ongoing solutions. A particular focus is given on solid storage and some of the recent advances on plasma hydrogen ion implantation which should allow not only the preparation of metal hydrides but also the imagination of a new refluing circuit. From hydrogen discovery to its use as an energy vector in cars this review wants to be as exhaustive as possible introducing the basics of hydrogen storage and discussing the experimental practicalities of car hydrogen fuel. It wants to serve as a guide for anyone wanting to undertake such a technology and to equip the reader with an advanced knowledge on hydrogen storage and hydrogen storage in hydrogen cars to stimulate further researches and yet more innovative applications for this highly interesting field.
OIES Podcast - Hydrogen Pipelines vs. HVDC Lines
Nov 2023
Publication
In this podcast David Ledesma talks to Aliaksei Patonia and Veronika Lenivova about Hydrogen pipelines and high-voltage direct current (HVDC) transmission lines and how Hydrogen pipelines offer the advantage of transporting larger energy volumes but existing projects are dwarfed by the vast networks of HVDC transmission lines. The podcast discusses how advocates for hydrogen pipelines see potential in expanding these networks capitalizing on hydrogen’s physical similarities to natural gas and the potential for cost savings. However hydrogen’s unique characteristics such as its small molecular size and compression requirements present construction challenges. On the other hand HVDC lines while less voluminous excel in efficiently transmitting green electrons over long distances. They already form an extensive global network and their efficiency makes them suitable for various applications. Yet intermittent renewable energy sources pose challenges for both hydrogen and electricity systems necessitating solutions like storage and blending.
The podcast can be found on their website.
The podcast can be found on their website.
The Use of Hydrogen as Alternative Fuel for Ship Propulsion: A Case Study of Full and Partial Retrofitting of Roll-on/Roll-off Vessels for Short Distance Routes
Oct 2023
Publication
Roll-on/Roll-Off (Ro-Ro) vessels including those without and with passenger accommodation Roll-on/roll-off passenger (Ro-Pax) can be totally or partially retrofitted to reduce the greenhouse gas (GHG) emissions in maritime transport not only during hoteling operation at the dock but also during service. This study is based on data of the vessel routes connecting the Port of Piombino to the Elba Island in Italy. Three retrofitting scenarios have been considered: replacement of the main and auxiliary engines with fuel cells (FC) (full retrofitting) replacement of the auxiliary engines with FCs (partial retrofitting) and replacement of the auxiliary engines with FCs and hoteling only with auxiliary engines for one specific vessel. The amount of hydrogen the filling time and the energy needed for production compression and pre-cooling of hydrogen have been calculated for the different scenarios.
Examining Real-Road Fuel Consumption Performance of Hydrogen-Fueled Series Hybrid Vehicles
Oct 2023
Publication
The use of hydrogen fuel produced from renewable energy sources is an effective way to reduce well-to-wheel CO2 emissions from automobiles. In this study the performance of a hydrogen-powered series hybrid vehicle was compared with that of other powertrains such as gasoline-powered hybrid fuel cell and electric vehicles in a simulation that could estimate CO2 emissions under real-world driving conditions. The average fuel consumption of the hydrogenpowered series hybrid vehicle exceeded that of the gasoline-powered series hybrid vehicle under all conditions and was better than that of the fuel cell vehicle under urban and winding conditions with frequent acceleration and deceleration. The driving range was longer than that of the batterypowered vehicle but approximately 60% of that of the gasoline-powered series hybrid. Regarding the life-cycle assessment of CO2 emissions fuel cell and electric vehicles emitted more CO2 during the manufacturing process. Regarding fuel production CO2 emissions from hydrogen and electric vehicles depend on the energy source. However in the future this problem can be solved by using carbon-free energy sources for fuel production. Therefore hydrogen-powered series hybrid vehicles show a high potential to be environmentally friendly alternative fuel vehicles.
Modelling and Operation Strategy Approaches for On-site Hydrogen Refuelling Stations
Aug 2023
Publication
The number of Fuel Cell Electric Vehicles (FCEVs) in circulation has undergone a significant increase in recent years. This trend is foreseen to be stronger in the near future. In correlation with the FCEVs market increase the hydrogen delivery infrastructure must be developed. With this aim many countries have announced ambitious projects. For example Spain has the objective of increasing the number of Hydrogen Refuelling Stations (HRS) with public access from three units in operation currently to about 150 by 2030. HRSs are complex systems with high variability in terms of layout design size of components operational strategy hydrogen generation method or hydrogen generation location. This paper is focused on on-site HRS with electrolysis-based hydrogen production which provides interesting advantages when renewable energy is utilized compared to off-site hydrogen production despite their complexity. To optimize HRS design and operation a simulation model must be implemented. This paper describes a generic on-site HRS with electrolysis-based hydrogen production a cascaded multi-tank storage system with multiple compressors renewable energy sources and multiple types of dispensing formats. A modelling approach of the layout is presented and tested with real-based parameters of an HRS currently under development which is capable of producing 11.34 kg/h of green H2 with irradiation at 1000 W/m2. For the operation an operational strategy is proposed. The modelled system is tested through several simulations. A sensitivity analysis of the effects of hydrogen demand and day-ahead hydrogen production objective on emissions demand satisfaction and variable costs is performed. Simulation results show how the operational strategy has achieved service up to 310 FCEVs refuelling events of heavy duty and light duty FCEVs bringing the total H2 sold up to almost 7200 H2kg in one month of winter. Additionally considering variable costs of the energy from the utility grid the model shows a profit in the range of 21–50 k€ for a daily demand of 60 H2kg/day and 100 H2kg/day respectively. In terms of emissions a year simulation with 60 H2kg/day of demand shows specific emissions in the production of H2 in Spain of 6.26 kgCO2eq/H2kg which represents a greenhouse gas emission intensity of 52.26 kgCO2eq/H2MJ.
Optimal Design and Analysis of a Hybrid Hydrogen Energy Storage System for an Island-Based Renewable Energy Community
Oct 2023
Publication
Installations of decentralised renewable energy systems (RES) are becoming increasing popular as governments introduce ambitious energy policies to curb emissions and slow surging energy costs. This work presents a novel model for optimal sizing for a decentralised renewable generation and hybrid storage system to create a renewable energy community (REC) developed in Python. The model implements photovoltaic (PV) solar and wind turbines combined with a hybrid battery and regenerative hydrogen fuel cell (RHFC). The electrical service demand was derived using real usage data from a rural island case study location. Cost remuneration was managed with an REC virtual trading layer ensuring fair distribution among actors in accordance with the European RED(III) policy. A multi-objective genetic algorithm (GA) stochastically determines the system capacities such that the inherent trade-off relationship between project cost and decarbonisation can be observed. The optimal design resulted in a levelized cost of electricity (LCOE) of 0.15 EUR/kWh reducing costs by over 50% compared with typical EU grid power with a project internal rate of return (IRR) of 10.8% simple return of 9.6%/year and return on investment (ROI) of 9 years. The emissions output from grid-only use was reduced by 72% to 69 gCO2 e/kWh. Further research of lifetime economics and additional revenue streams in combination with this work could provide a useful tool for users to quickly design and prototype future decentralised REC systems.
Power Cost and CO2 Emissions for a Microgrid with Hydrogen Storage and Electric Vehicles
Nov 2023
Publication
Hydrogen is considered the primary energy source of the future. The best use of hydrogen is in microgrids that have renewable energy sources (RES). These sources have a small impact on the environment when it comes to carbon dioxide (CO2 ) emissions and a power generation cost close to that of conventional power plants. Therefore it is important to study the impact on the environment and the power cost. The proposed microgrid comprises loads RESs (micro-hydro and photovoltaic power plants) a hydrogen storage tank an electric battery and fuel cell vehicles. The power cost and CO2 emissions are calculated and compared for various scenarios including the four seasons of the year compared with the work of other researchers. The purpose of this paper is to continuously supply the loads and vehicles. The results show that the microgrid sources and hydrogen storage can supply consumers during the spring and summer. For winter and autumn the power grid and steam reforming of natural gas must be used to cover the demand. The highest power costs and CO2 emissions are for winter while the lowest are for spring. The power cost increases during winter between 20:00 and 21:00 by 336%. The CO2 emissions increase during winter by 8020%.
Enabling Safe and Sustainable Hydrogen Mobility: Circular Economy-Driven Management of Hydrogen Vehicle Safety
Sep 2023
Publication
Hydrogen vehicles encompassing fuel cell electric vehicles (FCEVs) are pivotal within the UK’s energy landscape as it pursues the goal of net-zero emissions by 2050. By markedly diminishing dependence on fossil fuels FCEVs including hydrogen vehicles wield substantial influence in shaping the circular economy (CE). Their impact extends to optimizing resource utilization enabling zero-emission mobility facilitating the integration of renewable energy sources supplying adaptable energy storage solutions and interconnecting diverse sectors. The widespread adoption of hydrogen vehicles accelerates the UK’s transformative journey towards a sustainable CE. However to fully harness the benefits of this transition a robust investigation and implementation of safety measures concerning hydrogen vehicle (HV) use are indispensable. Therefore this study takes a holistic approach integrating quantitative risk assessment (QRA) and an adaptive decision-making trial and evaluation laboratory (DEMATEL) framework as pragmatic instruments. These methodologies ensure both the secure deployment and operational excellence of HVs. The findings underscore that the root causes of HV failures encompass extreme environments material defects fuel cell damage delivery system impairment and storage system deterioration. Furthermore critical driving factors for effective safety intervention revolve around cultivating a safety culture robust education/training and sound maintenance scheduling. Addressing these factors is pivotal for creating an environment conducive to mitigating safety and risk concerns. Given the intricacies of conducting comprehensive hydrogen QRAs due to the absence of specific reliability data this study dedicates attention to rectifying this gap. A sensitivity analysis encompassing a range of values is meticulously conducted to affirm the strength and reliability of our approach. This robust analysis yields precise dependable outcomes. Consequently decision-makers are equipped to discern pivotal underlying factors precipitating potential HV failures. With this discernment they can tailor safety interventions that lay the groundwork for sustainable resilient and secure HV operations. Our study navigates the intersection of HVs safety and sustainability amplifying their importance within the CE paradigm. Using the careful amalgamation of QRA and DEMATEL methodologies we chart a course towards empowering decision-makers with the insights to steer the hydrogen vehicle domain to safer horizons while ushering in an era of transformative eco-conscious mobility.
A Comparative Environmental Life Cycle Assessment Study of Hydrogen Fuel Electricity and Diesel Fuel for Public Buses
Aug 2023
Publication
Hydrogen fuel and electricity are energy carriers viewed as promising alternatives for the modernization and decarbonization of public bus transportation fleets. In order to choose development pathways that will lead transportation systems toward a sustainable future the authors developed an environmental model based on the Life Cycle Assessment approach. The model tested the impact of energy carrier consumption during driving as well as the electricity origin employed to power electric buses and produce hydrogen. Energy sources such as wind solar waste and grid electricity were investigated. The scope of the study included the life cycles of the energy carrier and the necessary infrastructure. The results were presented from two perspectives: the total environmental impact and global warming potential. In order to create a roadmap an original method for choosing sustainable development pathways was prepared. It was shown that the modernization of conventional bus fleets using hydrogen and electrical pathways can provide significant environmental benefits from both perspectives but especially in terms of global warming potential. It was emphasized that attention should be paid to the use of low- and zero-emission energy sources because their impact often strongly influenced the final environmental judgment. The energy carrier consumption also had a strong impact on the results obtained and that is why efforts should be made to reduce it. In addition it was confirmed that hydrogen and electricity production systems based on electricity generated by a waste-to-energy plant could be an environmentally reasonable dual solution for both sustainable waste management and meeting transport needs.
Conceptual Design of an Offshore Hydrogen Platform
Feb 2024
Publication
Offshore green hydrogen emerges as a guiding light in the global pursuit of environmental sustainability and net-zero objectives. The burgeoning expansion of offshore wind power faces significant challenges in grid integration. This avenue towards generating offshore green hydrogen capitalises on its ecological advantages and substantial energy potential to efficiently channel offshore wind power for onshore energy demands. However a substantial research void exists in efficiently integrating offshore wind electricity and green hydrogen. Innovative designs of offshore hydrogen platforms present a promising solution to bridge the gap between offshore wind and hydrogen integration. Surprisingly there is a lack of commercially established offshore platforms dedicated to the hydrogen industry. However the wealth of knowledge from oil and gas platforms contributes valuable insights to hydrogen platform design. Diverging from the conventional decentralised hydrogen units catering to individual turbines this study firstly introduces a pioneering centralised Offshore Green Hydrogen Platform (OGHP) which seamlessly integrates modular production storage and offloading modulars. The modular design of facilitates scalability as wind capacity increases. Through a detailed case study centred around a 100-Megawatt floating wind farm the design process of offshore green hydrogen modulars and its floating sub-structure is elucidated. Stability analysis and hydrodynamic analysis are performed to ensure the safety of the OGHP under the operation conditions. The case study will enhance our understanding OGHP and its modularised components. The conceptual design of modular OGHP offers an alternative solution to ‘‘Power-to-X’’ for offshore renewable energy sector.
Selecting Appropriate Energy Source Options for an Arctic Research Ship
Dec 2023
Publication
Interest in more sustainable energy sources has increased rapidly in the maritime industry and ambitious goals have been set for decreasing ship emissions. All industry stakeholders have reacted to this with different approaches including the optimisation of ship power plants the development of new energy-improving sub-systems for existing solutions or the design of entirely novel power plant concepts employing alternative fuels. This paper assesses the feasibility of different ship energy sources for an icebreaking Arctic research ship. To that end possible energy sources are assessed based on fuel infrastructure availability and operational endurance criteria in the operational area of interest. Promising alternatives are analysed further using the evidence-based Strengths Weaknesses Opportunities and Threats (SWOT) method. Then a more thorough investigation with respect to the required fuel tank space life cycle cost and CO2 emissions is implemented. The results demonstrate that marine diesel oil (MDO) is currently still the most convenient solution due to the space operational range and endurance limitations although it is possible to use liquefied natural gas (LNG) and methanol if the ship’s arrangement is radically redesigned which will also lead to reduced emissions and life cycle costs. The use of liquefied hydrogen as the only energy solution for the considered vessel was excluded from the potential options due to low volumetric energy density and high life cycle and capital costs. Even if it is used with MDO for the investigated ship the reduction in CO2 emissions will not be as significant as for LNG and methanol at a much higher capital and lifecycle cost. The advantage of the proposed approach is that unrealistic alternatives are eliminated in a systematic manner before proceeding to detailed techno-economic analysis facilitating the decision-making and investigation of various options in a more holistic manner.
Energy-exergy Evaluation of Liquefied Hydrogen Production System Based on Steam Methane Reforming and LNG Revaporization
Jul 2023
Publication
The research motivation of this paper is to utilize the large amount of energy wasted during the LNG (liquefied natural gas) gasification process and proposes a synergistic liquefied hydrogen (LH2) production and storage process scheme for LNG receiving station and methane reforming hydrogen production process - SMR-LNG combined liquefied hydrogen production system which uses the cold energy from LNG to pre-cool the hydrogen and subsequently uses an expander to complete the liquefaction of hydrogen. The proposed process is modeled and simulated by Aspen HYSYS software and its efficiency is evaluated and sensitivity analysis is carried out. The simulation results show that the system can produce liquefied hydrogen with a flow rate of 5.89t/h with 99.99% purity when the LNG supply rate is 50t/h. The power consumption of liquefied hydrogen is 46.6kWh/kg LH2; meanwhile the energy consumption of the HL subsystem is 15.9kWh/kg LH2 lower than traditional value of 17~19kWh/kg LH2. The efficiency of the hydrogen production subsystem was 16.9%; the efficiency of the hydrogen liquefaction (HL) subsystem was 29.61% which was significantly higher than the conventional industrial value of 21%; the overall energy efficiency (EE1) of the system was 56.52% with the exergy efficiency (EE2) of 22.2% reflecting a relatively good thermodynamic perfection. The energy consumption of liquefied hydrogen per unit product is 98.71 GJ/kg LH2.
Potential Economic Benefits of Carbon Dioxide (CO2) Reduction Due to Renewable Energy and Electrolytic Hydrogen Fuel Deployment Under Current and Long Term Forecasting of the Social Carbon Cost (SCC)
May 2019
Publication
The 2016 Paris Agreement (UNFCCC Authors 2015) is the latest of initiative to create an international consensus on action to reduce GHG emissions. However the challenge of meeting its targets lies mainly in the intimate relationship between GHG emissions and energy production which in turn links to industry and economic growth. The Middle East and North African region (MENA) particularly those nations rich oil and gas (O&G) resources depend on these as a main income source. Persuading the region to cut down on O&G production or reduce its GHG emissions is hugely challenging as it is so vital to its economic strength. In this paper an alternative option is established by creating an economic link between GHG emissions measured as their CO2 equivalent (CO2e) and the earning of profits through the concept of Social Carbon Cost (SCC). The case study is a small coastal city in Libya where 6% of electricity is assumed to be generated from renewable sources. At times when renewable energy (RE) output exceeds the demand for power the surplus is used for powering the production of hydrogen by electrolysis thus storing the energy and creating an emission-free fuel. Two scenarios are tested based on short and long term SCCs. In the short term scenario the amount of fossil fuel energy saved matches the renewable energy produced which equates to the same amount of curtailed O&G production. The O&G-producing region can earn profits in two ways: (1) by cutting down CO2 emissions as a result of a reduction in O&G production and (2) by replacing an amount of fossil fuel with electrolytically-produced hydrogen which creates no CO2 emissions. In the short term scenario the value of SCC saved is nearly 39% and in the long term scenario this rose to 83%.
Towards Renewable Hydrogen-based Electrolysis: Alkaline vs Proton Exchange Membrane
Jul 2023
Publication
This paper focuses on the battle for a dominant design for renewable hydrogen electrolysis in which the designs alkaline and proton exchange membrane compete for dominance. First a literature review is performed to determine the most relevant factors that influence technology dominance. Following that a Best Worst Method analysis is conducted by interviewing multiple industry experts. The most important factors appear to be: Price Safety Energy consumption Flexibility Lifetime Stack size and Materials used. The opinion of experts on Proton Exchange Membrane and alkaline electrolyser technologies is slightly skewed in favour of alkaline technologies. However the margin is too small to identify a winner in this technology battle. The following paper contributes to the ongoing research on modelling the process of technology selection in the energy sector.
Influence of Capillary Threshold Pressure and Injection Well Location on the Dynamic CO2 and H2 Storage Capacity for the Deep Geological Structure
Jul 2021
Publication
The subject of this study is the analysis of influence of capillary threshold pressure and injection well location on the dynamic CO2 and H2 storage capacity for the Lower Jurassic reservoir of the Sierpc structure from central Poland. The results of injection modeling allowed us to compare the amount of CO2 and H2 that the considered structure can store safely over a given time interval. The modeling was performed using a single well for 30 different locations considering that the minimum capillary pressure of the cap rock and the fracturing pressure should not be exceeded for each gas separately. Other values of capillary threshold pressure for CO2 and H2 significantly affect the amount of a given gas that can be injected into the reservoir. The structure under consideration can store approximately 1 Mt CO2 in 31 years while in the case of H2 it is slightly above 4000 tons. The determined CO2 storage capacity is limited; the structure seems to be more prospective for underground H2 storage. The CO2 and H2 dynamic storage capacity maps are an important element of the analysis of the use of gas storage structures. A much higher fingering effect was observed for H2 than for CO2 which may affect the withdrawal of hydrogen. It is recommended to determine the optimum storage depth particularly for hydrogen. The presented results important for the assessment of the capacity of geological structures also relate to the safety of use of CO2 and H2 underground storage space.
Socio-economic Aspects of Hydrogen Energy: An Integrative Review
Apr 2023
Publication
Hydrogen can be recognized as the most plausible fuel for promoting a green environment. Worldwide developed and developing countries have established their hydrogen research investment and policy frameworks. This analysis of 610 peer-reviewed journal articles from the last 50 years provides quantitative and impartial insight into the hydrogen economy. By 2030 academics and business professionals believe that hydrogen will complement other renewable energy (RE) sources in the energy revolution. This study conducts an integrative review by employing software such as Bibliometrix R-tool and VOSviewer on socio-economic consequences of hydrogen energy literature derived from the Scopus database. We observed that most research focuses on multidisciplinary concerns such as generation storage transportation application feasibility and policy development. We also present the conceptual framework derived from in-depth literature analysis as well as the interlinkage of concepts themes and aggregate dimensions to highlight research hotspots and emerging patterns. In the future factors such as green hydrogen generation hydrogen permeation and leakage management efficient storage risk assessment studies blending and techno-economic feasibility shall play a critical role in the socio-economic aspects of hydrogen energy research.
Minimizing Emissions from Grid-based Hydrogen Production in the United States
Jan 2023
Publication
Low-carbon hydrogen could be an important component of a net-zero carbon economy helping to mitigate emissions in a number of hard-to-abate sectors. The United States recently introduced an escalating production tax credit (PTC) to incentivize production of hydrogen meeting increasingly stringent embodied emissions thresholds. Hydrogen produced via electrolysis can qualify for the full subsidy under current federal accounting standards if the input electricity is generated by carbon-free resources but may fail to do so if emitting resources are present in the generation mix. While use of behind-the-meter carbon-free electricity inputs can guarantee compliance with this standard the PTC could also be structured to allow producers using grid-supplied electricity to qualify subject to certain clean energy procurement requirements. Herein we use electricity system capacity expansion modeling to quantitatively assess the impact of grid-connected electrolysis on the evolution of the power sector in the western United States through 2030 under multiple possible implementations of the clean hydrogen PTC. We find that subsidized grid-connected hydrogen production has the potential to induce additional emissions at effective rates worse than those of conventional fossil-based hydrogen production pathways. Emissions can be minimized by requiring grid-based hydrogen producers to match 100% of their electricity consumption on an hourly basis with physically deliverable ‘additional’ clean generation which ensures effective emissions rates equivalent to electrolysis exclusively supplied by behind-the-meter carbon-free generation. While these requirements cannot eliminate indirect emissions caused by competition for limited clean resources which we find to be a persistent result of large hydrogen production subsidies they consistently outperform alternative approaches relying on relaxed time matching or marginal emissions accounting. Added hydrogen production costs from enforcing an hourly matching requirement rather than no requirements are less than $1 kg−1 and can be near zero if clean firm electricity resources are available for procurement.
Performance and Cost Analysis of Hydrogen Production from Steam Reforming and Dehydrogenation of Ethanol
Aug 2020
Publication
Mitigation of carbon dioxide (CO2) emission has been a worldwide concern. Decreasing CO2 emission by converting it into higher value products such as methanol can be a promising way. However hydrogen (H2) cost and availability are one of key barriers to CO2 conversion. Ethanol can be a sustainable source for H2 due to its renewable nature and easy conversion to H2-rich gas mixtures through ethanol steam reforming process. Nevertheless steam reforming of ethanol generates CO2. Hence this research is focused on different methods of H2 productions about a 1665.47 t/y from ethanol for supplying to methanol plants was performed using Aspen PLUS V10. The ethanol steam reforming process required the lowest required ethanol feed for a certain amount of H2. In contrast the ethanol steam reforming process presented significant amount of CO2 emission from reaction and electricity consumption. But the ethanol dehydrogenation of ethanol not only generates H2 without CO2 emission from the reaction but also ethyl acetate or acetaldehyde which are value chemicals. However ethanol dehydrogenation processes in case II and III presented relatively higher cost because by-products (ethyl acetate or acetaldehyde) were rather difficult to be separated.
A Comprehensive Review on the Power Supply System of Hydrogen Production Electrolyzers for Future Integrated Energy Systems
Feb 2024
Publication
Hydrogen energy is regarded as an ideal solution for addressing climate change issues and an indispensable part of future integrated energy systems. The most environmentally friendly hydrogen production method remains water electrolysis where the electrolyzer constructs the physical interface between electrical energy and hydrogen energy. However few articles have reviewed the electrolyzer from the perspective of power supply topology and control. This review is the first to discuss the positioning of the electrolyzer power supply in the future integrated energy system. The electrolyzer is reviewed from the perspective of the electrolysis method the market and the electrical interface modelling reflecting the requirement of the electrolyzer for power supply. Various electrolyzer power supply topologies are studied and reviewed. Although the most widely used topology in the current hydrogen production industry is still single-stage AC/DC the interleaved parallel LLC topology constructed by wideband gap power semiconductors and controlled by the zero-voltage switching algorithm has broad application prospects because of its advantages of high power density high efficiency fault tolerance and low current ripple. Taking into account the development trend of the EL power supply a hierarchical control framework is proposed as it can manage the operation performance of the power supply itself the electrolyzer the hydrogen energy domain and the entire integrated energy system.
Optimal Energy Management of an Integrated Energy System with Multiple Hydrogen Sources
Sep 2023
Publication
Hydrogen is considered a promising alternative to fossil fuels in an integrated energy system (IES). In order to reduce the cost of hydrogen energy utilization and the carbon emissions of the IES this paper proposes a low-carbon dispatching strategy for a coordinated integrated energy system using green hydrogen and blue hydrogen. The strategy takes into account the economic and low-carbon complementarity between hydrogen production by water electrolysis and hydrogen production from natural gas. It introduces the green hydrogen production–storage–use module (GH-PSUM) and the blue hydrogen production–storage–use module (BH-PSUM) to facilitate the refined utilization of different types of hydrogen energy. Additionally the flexibility in hydrogen load supply is analyzed and the dynamic response mechanism of the hydrogen load supply structure (DRM-HLSS) is proposed to further reduce operating costs and carbon emissions. Furthermore a carbon trading mechanism (CTM) is introduced to constrain the carbon emissions of the integrated energy system. By comprehensively considering the constraints of each equipment the proposed model aims to minimize the total economic cost which includes wind power operation and curtailment penalty costs energy purchase costs blue hydrogen purification costs and carbon transaction costs. The rationality of the established scheduling model is verified through a comparative analysis of the scheduling results across multiple operating scenarios.
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.
Hydrogen Fuel Quality from Two Main Production Processes: Steam Methane Reforming and Proton Exchange Membrane Water Electrolysis
Oct 2019
Publication
Thomas Bacquart,
Karine Arrhenius,
Stefan Persijn,
Andrés Rojo,
Fabien Auprêtre,
Bruno Gozlan,
Abigail Morris,
Andreas Fischer,
Arul Murugan,
Sam Bartlett,
Niamh Moore,
Guillaume Doucet,
François Laridant,
Eric Gernot,
Teresa E. Fernandez,
Concepcion Gomez,
Martine Carré,
Guy De Reals and
Frédérique Haloua
The absence of contaminants in the hydrogen delivered at the hydrogen refuelling station is critical to ensure the length life of FCEV. Hydrogen quality has to be ensured according to the two international standards ISO 14687–2:2012 and ISO/DIS 19880-8. Amount fraction of contaminants from the two hydrogen production processes steam methane reforming and PEM water electrolyser is not clearly documented. Twenty five different hydrogen samples were taken and analysed for all contaminants listed in ISO 14687-2. The first results of hydrogen quality from production processes: PEM water electrolysis with TSA and SMR with PSA are presented. The results on more than 16 different plants or occasions demonstrated that in all cases the 13 compounds listed in ISO 14687 were below the threshold of the international standards. Several contaminated hydrogen samples demonstrated the needs for validated and standardised sampling system and procedure. The results validated the probability of contaminants presence proposed in ISO/DIS 19880-8. It will support the implementation of ISO/ DIS 19880-8 and the development of hydrogen quality control monitoring plan. It is recommended to extend the study to other production method (i.e. alkaline electrolysis) the HRS supply chain (i.e. compressor) to support the technology growth.
Work Efficiency and Economic Efficiency of Actual Driving Test of Proton Exchange Membrane Fuel Cell Forklift
Aug 2023
Publication
A 3.5 tonne forklift containing proton exchange membrane fuel cells (PEMFCs) and lithium-ion batteries was manufactured and tested in a real factory. The work efficiency and economic applicability of the PEMFC forklift were compared with that of a lithium-ion battery-powered forklift. The results showed that the back-pressure of air was closely related to the power density of the stack whose stability could be improved by a reasonable control strategy and membrane electrode assemblies (MEAs) with high consistency. The PEMFC powered forklift displayed 40.6% higher work efficiency than the lithium-ion battery-powered forklift. Its lower use-cost compared to internal engine-powered forklifts is beneficial to the commercialization of this product.
Techno‑Economic Comparative Analysis of Two Hybrid Renewable Energy Systems for Powering a Simulated House, including a Hydrogen Vehicle Load at Jeju Island
Nov 2023
Publication
This work undertakes a techno‑economic comparative analysis of the design of photo‑ voltaic panel/wind turbine/electrolyzer‑H2 tank–fuel cell/electrolyzer‑H2 tank (configuration 1) and photovoltaic panel/wind turbine/battery/electrolyzer‑H2 tank (configuration 2) to supply electricity to a simulated house and a hydrogen‑powered vehicle on Jeju Island. The aim is to find a system that will make optimum use of the excess energy produced by renewable energies to power the hydrogen vehicle while guaranteeing the reliability and cost‑effectiveness of the entire system. In addition to evaluating the Loss of Power Supply Probability (LPSP) and the Levelized Cost of Energy (LCOE) the search for achieving that objective leads to the evaluation of two new performance indicators: Loss of Hydrogen Supply Probability (LHSP) and Levelized Cost of Hydrogen (LCOH). After anal‑ ysis for 0 < LPSP < 1 and 0 < LHSP < 1 used as the constraints in a multi‑objective genetic algorithm configuration 1 turns out to be the most efficient loads feeder with an LCOE of 0.3322 USD/kWh an LPSP of 0% concerning the simulated house load an LCOH of 11.5671 USD/kg for a 5 kg hydrogen storage and an LHSP of 0.0043% regarding the hydrogen vehicle load.
A Computational Study of Hydrogen Dispersion and Explosion after Large-Scale Leakage of Liquid Hydrogen
Nov 2023
Publication
This study employs the FLACS code to analyze hydrogen leakage vapor dispersion and subsequent explosions. Utilizing pseudo-source models a liquid pool model and a hybrid model combining both we investigate dispersion processes for varying leak mass flow rates (0.225 kg/s and 0.73 kg/s) in a large open space. We also evaluate explosion hazards based on overpressure and impulse effects on humans. The computational results compared with experimental data demonstrated reasonable hydrogen vapor cloud concentration predictions especially aligned with the wind direction. For higher mass flow rate of 0.73 kg/s the pseudo-source model exhibited the most reasonable predictive performance for locations near the leak source despite the hybrid model yielded similar results to the pseudo-source model while the liquid pool model was more suitable for lower mass flow rate of 0.225 kg/s. Regarding explosion analyses using overpressure-impulse diagram higher mass flow rates leaded to potentially fatal overpressure and impulse effects on humans. However lower mass flow rates may cause severe eardrum damage at the maximum overpressure point.
CFD Model of Refuelling through the Entire Equipment of a Hydrogen Refuelling Station
Dec 2023
Publication
This paper aims at the development and validation of a computational fluid dynamic (CFD) model for simulations of the refuelling process through the entire equipment of the hydrogen refuelling station (HRS). The absence of such models hinders the design of inherently safer refuelling protocols for an arbitrary combination of HRS equipment hydrogen storage parameters and environmental conditions. The CFD model is validated against the complete process of refuelling lasting 195s in Test No.1 performed by the National Renewable Energy Laboratory (NREL). The test equipment includes high-pressure tanks of HRS pressure control valve (PCV) valves pipes breakaway hose and nozzle all the way up to three onboard tanks. The model accurately reproduced hydrogen temperature and pressure through the entire line of HRS equipment. A standout feature of the CFD model distinguishing it from simplified models is the capability to predict temperature non-uniformity in onboard tanks a crucial factor with significant safety implications.
OIES Podcast - Aviation Fuels and the Potential of Hydrogen
Feb 2024
Publication
In the latest OIES podcast from the Hydrogen Programme James Henderson talks to Abdurahman Alsulaiman about his latest paper entitled “Navigating Turbulence: Hydrogen’s Role in the Decarbonisation of the Aviation Sector.” In the podcast we discuss the current balance of fuels in the aviation sector the importance of increasing efficiency of aero-engines and the impact of increasing passenger miles travelled. The podcast then considers different decarbonisation options for the sector focussing on a change of engine technology to allow the use of alternative fuels such as hydrogen or electricity but also looking at the potential for hydrogen to play an important role in the development of Sustainable Aviation Fuels (SAFs) for use with current engine technology. We also look at Low Carbon Aviation Fuels which are essentially existing fuels derived from a significantly decarbonised supply chain and assess whether they have an important role to play as the aviation sector targets a net zero outcome.
The podcast can be found on their website.
The podcast can be found on their website.
Optimal Hydrogen Infrastructure Planning for Heat Decarbonisation
Feb 2024
Publication
Energy decarbonisation is essential to achieve Net-Zero emissions goal by 2050. Consequently investments in alternative low-carbon pathways and energy carriers for the heat sector are required. In this study we propose an optimisation framework for the transition of heat sector in Great Britain focusing on hydrogen infrastructure decisions. A spatially-explicit mixed-integer linear programming (MILP) evolution model is developed to minimise the total system’s cost considering investment and operational decisions. The optimisation framework incorporates both long-term planning horizon of 5-year steps from 2035 to 2050 and typical days with hourly resolution. Aiming to alleviate the computational effort of such multiscale model two hierarchical solution approaches are suggested that result in computational time reduction. From the optimisation results it is shown that the installation of gas reforming hydrogen production technologies with CCS and biomass gasification with CCS can provide a cost-effective strategy achieving decarbonisation goal. What-if analysis is conducted to demonstrate further insights for future hydrogen infrastructure investments. Results indicate that as cost is highly dependent on natural gas price Water Electrolysis capacity increases significantly when gas price rises. Moreover the introduction of carbon tax policy can lead to lower CO2 net emissions.
Exploring Dilution Potential for Full Load Operation of Medium Duty Hydrogen Engine for the Transport Sector
Jul 2023
Publication
The current political scenario and the concerns for global warming have pushed very harsh regulations on conventional propulsion systems based on the use of fossil fuels. New technologies are being promoted but their current technological status needs further research and development for them to become a competitive substitute for the ever-present internal combustion engine. Hydrogen-fueled internal combustion engines have demonstrated the potential of being a fast way to reach full decarbonization of the transport sector but they still have to face some limitations in terms of the operating range of the engine. For this reason the present work evaluates the potential of reaching full load operation on a conventional diesel engine assuming the minimum modifications required to make it work under H2 combustion. This study shows the methodology through which the combustion model was developed and then used to evaluate a multi-cylinder engine representative of the medium to high duty transport sector. The evaluation included different strategies of dilution to control the combustion performance and the results show that the utilization of EGR brings different benefits to engine operation in terms of efficiency improvement and emissions reduction. Nonetheless the requisites defined for the needed turbocharging system are harsher than expected and result in a potential non-conventional technical solution.
CFD Simulations of Hydrogen Tank Fuelling: Sensitivity to Turbulence Model and Grid Resolution
Dec 2023
Publication
CFD modelling of compressed hydrogen fuelling provides information on the hydrogen and tank structure temperature dynamics required for onboard storage tank design and fuelling protocol development. This study compares five turbulence models to develop a strategy for costeffective CFD simulations of hydrogen fuelling while maintaining a simulation accuracy acceptable for engineering analysis: RANS models k-ε and RSM; hybrid models SAS and DES; and LES model. Simulations were validated against the fuelling experiment of a Type IV 29 L tank available in the literature. For RANS with wall functions and blended models with near-wall treatment the simulated average hydrogen temperatures deviated from the experiment by 1–3% with CFL ≈ 1–3 and dimensionless wall distance y + ≈ 50–500 in the tank. To provide a similar simulation accuracy the LES modelling approach with near-wall treatment requires mesh with wall distance y + ≈ 2–10 and demonstrates the best-resolved flow field with larger velocity and temperature gradients. LES simulation on this mesh however implies a ca. 60 times longer CPU time compared to the RANS modelling approach and 9 times longer compared to the hybrid models due to the time step limit enforced by the CFL ≈ 1.0 criteria. In all cases the simulated pressure histories and inlet mass flow rates have a difference within 1% while the average heat fluxes and maximum hydrogen temperature show a difference within 10%. Compared to LES the k-ε model tends to underestimate and DES tends to overestimate the temperature gradient inside the tank. The results of RSM and SAS are close to those of LES albeit of 8–9 times faster simulations.
Alternatives for Transport, Storage in Port and Bunkering Systems for Offshore Energy to Green Hydrogen
Nov 2023
Publication
Offshore electricity production mainly by wind turbines and eventually floating PV is expected to increase renewable energy generation and their dispatchability. In this sense a significant part of this offshore electricity would be directly used for hydrogen generation. The integration of offshore energy production into the hydrogen economy is of paramount importance for both the techno-economic viability of offshore energy generation and the hydrogen economy. An analysis of this integration is presented. The analysis includes a discussion about the current state of the art of hydrogen pipelines and subsea cables as well as the storage and bunkering system that is needed on shore to deliver hydrogen and derivatives. This analysis extends the scope of most of the previous works that consider port-to-port transport while we report offshore to port. Such storage and bunkering will allow access to local and continental energy networks as well as to integrate offshore facilities for the delivery of decarbonized fuel for the maritime sector. The results of such state of the art suggest that the main options for the transport of offshore energy for the production of hydrogen and hydrogenated vectors are through direct electricity transport by subsea cables to produce hydrogen onshore or hydrogen transport by subsea pipeline. A parametric analysis of both alternatives focused on cost estimates of each infrastructure (cable/pipeline) and shipping has been carried out versus the total amount of energy to transport and distance to shore. For low capacity (100 GWh/y) an electric subsea cable is the best option. For high-capacity renewable offshore plants (TWh/y) pipelines start to be competitive for distances above approx. 750 km. Cost is highly dependent on the distance to land ranging from 35 to 200 USD/MWh.
Energy Transition Technology Comes With New Process Safety Challenges and Risks
Jul 2023
Publication
This paper intends to give an impression of new technologies and processes that are in development for application to achieve decarbonization and about which less or no experience on associated hazards exists in the process industry. More or less an exception is hydrogen technology because its hazards are relatively known and there is industry experience in handling it safely but problems will arise when it is produced stored and distributed on a large scale. So when its use spreads to communities and it becomes as common as natural gas now measures to control the risks will be needed. And even with hydrogen surprise findings have been shown lately e.g. its BLEVE behavior when in a liquified form stored in a vessel heated externally. Substitutes for hydrogen are not without hazard concern either. The paper will further consider the hazards of energy storage in batteries and the problems to get those hazards under control. Relatively much attention will be paid to the electrification of the process industry. Many new processes are being researched which given green energy will be beneficial to reduce greenhouse gases and enhance sustainability but of which hazards are rather unknown. Therefore as last chapter the developments with respect to the concept of hazard identification and scenario definition will be considered in quite detail. Improvements in that respect are also being possible due to the digitization of the industry and the availability of data and considering the entire life cycle all facilitated by the data model standard ISO 15926 with the scope of integration of life-cycle data for process plants including oil and gas production facilities. Conclusion is that the new technologies and processes entail new process and personal hazards and that much effort is going into renewal but safety analyses are scarce. Right in a period of process renewal attention should be focused on possibilities to implement inherently safer design.
A Cost Comparison of Various Hourly-reliable and Net-zero Hydrogen Production Pathways in the United States
Nov 2023
Publication
Hydrogen (H2) as an energy carrier may play a role in various hard-to-abate subsectors but to maximize emission reductions supplied hydrogen must be reliable low-emission and low-cost. Here we build a model that enables direct comparison of the cost of producing net-zero hourly-reliable hydrogen from various pathways. To reach net-zero targets we assume upstream and residual facility emissions are mitigated using negative emission technologies. For the United States (California Texas and New York) model results indicate nextdecade hybrid electricity-based solutions are lower cost ($2.02-$2.88/kg) than fossil-based pathways with natural gas leakage greater than 4% ($2.73-$5.94/ kg). These results also apply to regions outside of the U.S. with a similar climate and electric grid. However when omitting the net-zero emission constraint and considering the U.S. regulatory environment electricity-based production only achieves cost-competitiveness with fossil-based pathways if embodied emissions of electricity inputs are not counted under U.S. Tax Code Section 45V guidance.
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.
Potential-risk and No-regret Options for Urban Energy System Design - A Sensitivity Analysis
Jan 2024
Publication
This study identifies supply options for sustainable urban energy systems which are robust to external system changes. A multi-criteria optimization model is used to minimize greenhouse gas (GHG) emissions and financial costs of a reference system. Sensitivity analyses examine the impact of changing boundary conditions related to GHG emissions energy prices energy demands and population density. Options that align with both financial and emission reduction and are robust to system changes are called “no-regret” options. Options sensitive to system changes are labeled as “potential-risk” options.<br/>There is a conflict between minimizing GHG emissions and financial costs. In the reference case the emission-optimized scenario enables a reduction of GHG emissions (-93%) but involves higher costs (+160%) compared to the financially-optimized scenario.<br/>No-regret options include photovoltaic systems decentralized heat pumps thermal storages electricity exchange between sub-systems and with higher-level systems and reducing energy demands through building insulation behavioral changes or the decrease of living space per inhabitant. Potential-risk options include solar thermal systems natural gas technologies high-capacity battery storages and hydrogen for buildiing energy supply.<br/>When energy prices rise financially-optimized systems approach the least-emission system design. The maximum profitability of natural gas technologies was already reached before the 2022 European energy crisis.
A Review of Hydrogen-based Hybrid Renewable Energy Systems: Simulation and Optimization with Artificial Intelligence
Nov 2021
Publication
With the massive use of traditional fossil fuels greenhouse gas emissions are increasing and environmental pollution is becoming an increasingly serious problem which led to an imminent energy transition. Therefore the development and application of renewable energy are particularly important. This paper reviews a wide range of issues associated with hybrid renewable energy systems (HRESs). The issues concerning system configurations energy storage options simulation and optimization with artificial intelligence are discussed in detail. Storage technology options are introduced for stand-alone (off-grid) and grid-connected (on-grid) HRESs. Different optimization methodologies including classical techniques intelligent techniques hybrid techniques and software tools for sizing system components are presented. Besides the artificial intelligence methods for optimizing the solar/wind HRESs are discussed in detail.
Hydrogen–Natural Gas Mix—A Viable Perspective for Environment and Society
Aug 2023
Publication
The increase in demand and thus the need to lower its price has kept C-based fuels as the main source. In this context the use of oil and gas has led to increased climate change resulting in greenhouse gases. The high percentage of emissions over 40% is due to the production of electricity heat or/and energy transport. This is the main reason for global warming and the extreme and increasingly common climate change occurrences with all of nature being affected. Due to this reason in more and more countries there is an increased interest in renewable energies from sustainable sources with a particular emphasis on decarbonisation. One of the energies analysed for decarbonisation that will play a role in future energy systems is hydrogen. The development of hydrogen–natural gas mixtures is a major challenge in the field of energy and fuel technology. This article aims to highlight the major challenges associated with researching hydrogen–natural gas blends. Meeting this challenge requires a comprehensive research and development effort including exploring appropriate blending techniques optimising performance addressing infrastructure requirements and considering regulatory considerations. Overcoming this challenge will enable the full potential of hydrogen–natural gas blends to be realised as a clean and sustainable energy source. This will contribute to the global transition to a greener and more sustainable future. Several international European and Romanian studies projects and legislative problems are being analysed. The mix between H2 and natural gas decreases fugitive emissions. In contrast using hydrogen increases the risk of fire more than using natural gas because hydrogen is a light gas that easily escapes and ignites at almost any concentration in the air.
Integration of Air-cooled Multi-stack Polymer Electrolyte Fuel Cell Systems into Renewable Microgrids
May 2022
Publication
Currently there is a growing interest in increasing the power range of air-cooled fuel cells (ACFCs) as they are cheaper easier to use and maintain than water-cooled fuel cells (WCFCs). However air-cooled stacks are only available up to medium power (<10 kW). Therefore a good solution may be the development of ACFCs consisting of several stacks until the required power output is reached. This is the concept of air-cooled multi-stack fuel cell (AC-MSFC). The objective of this work is to develop a turnkey solution for the integration of AC-MSFCs in renewable microgrids specifically those with high-voltage DC (HVDC) bus. This is challenging because the AC-MSFCs must operate in the microgrid as a single ACFC with adjustable power depending on the number of stacks in operation. To achieve this the necessary power converter (ACFCs operate at low voltages so high conversion rates are required) and control loops must be developed. Unlike most designs in the literature the proposed solution is compact forming a system (AC-MSFCS) with a single input (hydrogen) and a single output (high voltage regulated power or voltage) that can be easily integrated into any microgrid and easily scalable depending on the power required. The developed AC-MSFCS integrates stacks balance of plant data acquisition and instrumentation power converters and local controllers. In addition a virtual instrument (VI)has been developed which connected to the energy management system (EMS) of the microgrid allows monitoring of the entire AC-MSFCS (operating temperature purging cell voltage monitoring for degradation evaluation stacks operating point control and alarm and event management) as well as serving as a user interface. This allows the EMS to know the degradation of each stack and to carry out energy distribution strategies or specific maintenance actions which improves efficiency lifespan and of course saves costs. The experimental results have been excellent in terms of the correct operation of the developed AC-MSFCS. Likewise the accumulated degradation of the stacks was quantified showing cells with a degradation of >80%. The excellent electrical and thermal performance of the developed power converter was also validated which allowed the correct and efficient supply of regulated power (average efficiency above 90%) to the HVDC bus according to the power setpoint defined by the EMS of the microgrid.
Climate Change Mitigation Potentials of on Grid-connected Power-to-X Fuels and Advanced Biofuels for the European Maritime Transport
Jul 2023
Publication
This study proposes a country-based life-cycle assessment (LCA) of several conversion pathways related 10 to both on grid-connected Power-to-X (PtX) fuels and advanced biofuel production for maritime transport 11 in Europe. We estimate the biomass resource availability (both agricultural and forest residues and 12 second-generation energy crops from abandoned cropland) electricity mix and a future-oriented 13 prospective LCA to assess how future climate change mitigation policies influence the results. Our results 14 indicate that the potential of PtX fuels to achieve well-to-wake greenhouse gas intensities lower than 15 those of fossil fuels is limited to countries with a carbon intensity of the electricity mix below 100 gCO2eq kWh-1 16 . The more ambitious FuelEU Maritime goal could be achieved with PtX only if connected to electricity sources below ca. 17 gCO2eq kWh-1 17 which can become possible for most of the national 18 electricity mix in Europe by 2050 if renewable energy sources will become deployed at large scales. For 19 drop-in and hydrogen-based biofuels biomass residues have a higher potential to reduce emissions than 20 dedicated energy crops. In Europe the potentials of energy supply from all renewable and low-carbon 21 fuels (RLFs) range from 32-149% of the current annual fuel consumption in European maritime transport. 22 The full deployment of RLFs with carbon capture and storage technologies could mitigate up to 184% of 23 the current well-to-wake shipping emissions in Europe. Overall our study highlights how the strategic use 24 of both hydrogen-based biofuels and PtX fuels can contribute to the climate mitigation targetsfor present 25 and future scenarios of European maritime transport.
Hopes and Fears for a Sustainable Energy Future: Enter the Hydrogen Acceptance Matrix
Feb 2024
Publication
Hydrogen-fuelled technologies for home heating and cooking may provide a low-carbon solution for decarbonising parts of the global housing stock. For the transition to transpire the attitudes and perceptions of consumers must be factored into policy making efforts. However empirical studies are yet to explore potential levels of consumer heterogeneity regarding domestic hydrogen acceptance. In response this study explores a wide spectrum of consumer responses towards the prospect of hydrogen homes. The proposed spectrum is conceptualised in terms of the ‘domestic hydrogen acceptance matrix’ which is examined through a nationally representative online survey conducted in the United Kingdom. The results draw attention to the importance of interest and engagement in environmental issues knowledge and awareness of renewable energy technologies and early adoption potential as key drivers of domestic hydrogen acceptance. Critically strategic measures should be taken to convert hydrogen scepticism and pessimism into hope and optimism by recognising the multidimensional nature of consumer acceptance. To this end resources should be dedicated towards increasing the observability and trialability of hydrogen homes in proximity to industrial clusters and hubs where the stakes for consumer acceptance are highest. Progress towards realising a net-zero society can be supported by early stakeholder engagement with the domestic hydrogen acceptance matrix.
Towards Energy Freedom: Exploring Sustainable Solutions for Energy Independence and Self-sufficiency using Integrated Renewable Energy-driven Hydrogen System
Jan 2024
Publication
n the pursuit of sustainable energy solutions the integration of renewable energy sources and hydrogen technologies has emerged as a promising avenue. This paper introduces the Integrated Renewable Energy-Driven Hydrogen System as a holistic approach to achieve energy independence and self-sufficiency. Seamlessly integrating renewable energy sources hydrogen production storage and utilization this system enables diverse applications across various sectors. By harnessing solar and/or wind energy the Integrated Renewable EnergyDriven Hydrogen System optimizes energy generation distribution and storage. Employing a systematic methodology the paper thoroughly examines the advantages of this integrated system over other alternatives emphasizing its zero greenhouse gas emissions versatility energy resilience and potential for large-scale hydrogen production. Thus the proposed system sets our study apart offering a distinct and efficient alternative compared to conventional approaches. Recent advancements and challenges in hydrogen energy are also discussed highlighting increasing public awareness and technological progress. Findings reveal a payback period ranging from 2.8 to 6.7 years depending on the renewable energy configuration emphasizing the economic attractiveness and potential return on investment. This research significantly contributes to the ongoing discourse on renewable energy integration and underscores the viability of the Integrated Renewable EnergyDriven Hydrogen System as a transformative solution for achieving energy independence. The employed model is innovative and transferable to other contexts.
Renewable Hydrogen Standards, Certifications, and Labels: A State-of-the-art Review from a Sustainability Systems Governance Perspective
Feb 2024
Publication
A range of existing and newly developed hydrogen standards certification and labelling (SCL) schemes aim to promote the role of ‘renewable’ ‘clean’ or ‘green’ hydrogen in decarbonising energy transitions. This paper analyses a sample of these SCLs to assess their role in the scaling up of renewable hydrogen and its derivatives. To analyse these hydrogen SCLs we embellish a novel conceptual framework that brings together Sustainability Systems Thinking and Governance (SSG) literatures. The results reveal noteworthy scheme differences in motivation approach criteria and governance; highlighting the complex interconnected and dynamic reality within which energy systems are embedded. We consider whether the sustainable utilisation of renewable hydrogen is well-served by the proliferation of SCLs and recommend an SSG-informed approach. An SSG approach will better promote collaboration towards an authoritative global multistakeholder compromise on hydrogen certification that balances economic considerations with social and environmental dimensions.
Multi-criteria Site Selection Workflow for Geological Storage of Hydrogen in Depleted Gas Fields: A Case for the UK
Oct 2023
Publication
Underground hydrogen storage (UHS) plays a critical role in ensuring the stability and security of the future clean energy supply. However the efficiency and reliability of UHS technology depend heavily on the careful and criteria-driven selection of suitable storage sites. This study presents a hybrid multi-criteria decision-making framework integrating the Analytical Hierarchy Process (AHP) and Preference Ranking Organisation Method for Enrichment of Evaluations (PROMETHEE) to identify and select the best hydrogen storage sites among depleted gas reservoirs in the UK. To achieve this a new set of site selection criteria is proposed in light of the technical and economic aspects of UHS including location reservoir rock quality and tectonic characteristics maximum achievable hydrogen well deliverability rate working gas capacity cushion gas volume requirement distance to future potential hydrogen clusters and access to intermittent renewable energy sources (RESs). The framework is implemented to rank 71 reservoirs based on their potential and suitability for UHS. Firstly the reservoirs are thoroughly evaluated for each proposed criterion and then the AHP-PROMETHEE technique is employed to prioritise the criteria and rank the storage sites. The study reveals that the total calculated working gas capacity based on single-well plateau withdrawal rates is around 881 TWh across all evaluated reservoirs. The maximum well deliverability rates for hydrogen withdrawal are found to vary considerably among the sites; however 22 % are estimated to have deliverability rates exceeding 100 sm3 /d and 63 % are located within a distance of 100 km from a major hydrogen cluster. Moreover 70 % have access to nearby RESs developments with an estimated cumulative RESs capacity of approximately 181 GW. The results highlight the efficacy of the proposed multicriteria site selection framework. The top five highest-ranked sites for UHS based on the evaluated criteria are the Cygnus Hamilton Saltfleetby Corvette and Hatfield Moors gas fields. The insights provided by this study can contribute to informed decision-making sustainable development and the overall progress of future UHS projects within the UK and globally.
Management of Hybrid Wind and Photovoltaic System Electrolyzer for Green Hydrogen Production and Storage in the Presence of a Small Fleet of Hydrogen Vehicles— An Economic Assessment
Dec 2023
Publication
Nowadays with the need for clean and sustainable energy at its historical peak new equipment strategies and methods have to be developed to reduce environmental pollution. Drastic steps and measures have already been taken on a global scale. Renewable energy sources (RESs) are being installed with a growing rhythm in the power grids. Such installations and operations in power systems must also be economically viable over time to attract more investors thus creating a cycle where green energy e.g. green hydrogen production will be both environmentally friendly and economically beneficial. This work presents a management method for assessing wind–solar– hydrogen (H2 ) energy systems. To optimize component sizing and calculate the cost of the produced H2 the basic procedure of the whole management method includes chronological simulations and economic calculations. The proposed system consists of a wind turbine (WT) a photovoltaic (PV) unit an electrolyzer a compressor a storage tank a fuel cell (FC) and various power converters. The paper presents a case study of green hydrogen production on Sifnos Island in Greece through RES together with a scenario where hydrogen vehicle consumption and RES production are higher during the summer months. Hydrogen stations represent H2 demand. The proposed system is connected to the main power grid of the island to cover the load demand if the RES cannot do this. This study also includes a cost analysis due to the high investment costs. The levelized cost of energy (LCOE) and the cost of the produced H2 are calculated and some future simulations correlated with the main costs of the components of the proposed system are pointed out. The MATLAB language is used for all simulations.
Investigation of a Community-based Clean Energy System Holistically with Renewable and Hydrogen Energy Options for Better Sustainable Development
Jan 2024
Publication
This study develops a novel community-based integrated energy system where hydrogen and a combination of renewable energy sources are considered uniquely for implementation. In this regard three different communities situated in Kenya the United States and Australia are studied for hydrogen production and meeting the energy demands. To provide a variety of energy demands this study combines a multigenerational geothermal plant with a hybrid concentrated solar power and photovoltaic solar plant. Innovations in hydrogen production and renewable energy are essential for reducing carbon emissions. By combining the production of hydrogen with renewable energy sources this system seeks to move away from the reliance on fossil fuels and toward sustainability. The study investigates various research subjects using a variety of methods. The performance of the geothermal source is considered through energetic and exergetic thermodynamic analysis. The software System Advisor Model (SAM) and RETscreen software packages are used to analyze the other sub-systems including Concentrate Solar PV solar and Combined Heat and Power Plant. Australian American and Kenyan communities considered for this study were found to have promising potential for producing hydrogen and electricity from renewable sources. The geothermal output is expected to be 35.83 MW 122.8 MW for space heating 151.9 MW for industrial heating and 64.25 MW for hot water. The overall geothermal energy and exergy efficiencies are reported as 65.15% and 63.54% respectively. The locations considered are expected to have annual solar power generation and hydrogen production capacities of 158MW 237MW 186MW 235 tons 216 tons and 313 tons respectively.
Split Injection Strategies for a High-pressure Hydrogen Direct Injection in a Small-bore Dual-fuel Diesel Engine
Jan 2024
Publication
Hydrogen-diesel dual direct-injection (H2DDI) engines present a promising pathway towards cleaner and more efficient transportation. In this study hydrogen split injection strategies were explored in an automotive-size single-cylinder compression ignition (CI) engine with a focus on varying the injection timings and energy fractions. The engine was operated at an intermediate load with fixed combustion phasing through adjustments of pilot diesel injection timing. An energy substitution principle guided the variation in energy fraction between the two hydrogen injections and then diesel injection while keeping the total energy input constant. The findings demonstrate that early first hydrogen injection timings lead to characteristics indicative of premixed combustion reflecting a high homogeneity of the hydrogen-air mixture. In contrast hydrogen stratification levels were predominantly influenced by later second injection timings with mixing-controlled combustion behaviour apparent for very late injections near top dead centre or when the second hydrogen injection held high energy fractions which led to decreased nitrogen oxides (NOx: NO and NO2) emissions. The carbon dioxide (CO2) emissions did not show high sensitivity to the hydrogen split injection strategies exhibiting about 77 % reduction compared to the diesel baseline due primarily to increased hydrogen energy fraction of up to 90 %
Advancing a Hydrogen Economy in Australia: Public Perceptions and Aspirations
Nov 2023
Publication
Supporters of hydrogen energy urge scaling up technology and reducing costs for competitiveness. This paper explores how hydrogen energy technologies (HET) are perceived by Australia’s general population and considers the way members of the public imagine their role in the implementation of hydrogen energy now and into the future. The study combines a nationally representative survey (n = 403) and semi-structured interviews (n = 30). Results show age and gender relationships with self-reported hydrogen knowledge. Half of the participants obtained hydrogen information from televised media. Strong support was observed for renewable hydrogen while coal (26%) and natural gas (41%) versions had less backing. Participants sought more safety-related information (41% expressed concern). Most felt uncertain about influencing hydrogen decisions and did not necessarily recognise they had agency beyond their front fence. Exploring the link between political identity and agency in energy decision-making is needed with energy democracy a potentially productive direction.
Suitability and Energy Sustainability of Atmospheric Water Generation Technology for Green Hydrogen Production
Sep 2023
Publication
This research investigated the suitability of air-to-water generator (AWG) technology to address one of the main concerns in green hydrogen production namely water supply. This study specifically addresses water quality and energy sustainability issues which are crucial research questions when AWG technology is intended for electrolysis. To this scope a reasoned summary of the main findings related to atmospheric water quality has been provided. Moreover several experimental chemical analyses specifically focused on meeting electrolysis process requirements on water produced using a real integrated AWG system equipped with certified materials for food contact were discussed. To assess the energy sustainability of AWGs in green hydrogen production a case study was presented regarding an electrolyzer plant intended to serve as energy storage for a 2 MW photovoltaic field on Iriomote Island. The integrated AWG used for the water quality analyses was studied in order to determine its performance in the specific island climate conditions. The production exceeded the needs of the electrolyzer; thus the overproduction was considered for the panels cleaning due to the high purity of the water. Due to such an operation the efficiency recovery was more than enough to cover the AWG energy consumption. This paper on the basis of the quantity results provides the first answers to the said research questions concerning water quality and energy consumption establishing the potential of AWG as a viable solution for addressing water scarcity and enhancing the sustainability of electrolysis processes in green hydrogen production.
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