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Water Electrolysis: From Textbook Knowledge to the Latest Scientific Strategies and Industrial Developments
May 2022
Publication
Replacing fossil fuels with energy sources and carriers that are sustainable environmentally benign and affordable is amongst the most pressing challenges for future socio-economic development. To that goal hydrogen is presumed to be the most promising energy carrier. Electrocatalytic water splitting if driven by green electricity would provide hydrogen with minimal CO2 footprint. The viability of water electrolysis still hinges on the availability of durable earth-abundant electrocatalyst materials and the overall process efficiency. This review spans from the fundamentals of electrocatalytically initiated water splitting to the very latest scientific findings from university and institutional research also covering specifications and special features of the current industrial processes and those processes currently being tested in large-scale applications. Recently developed strategies are described for the optimisation and discovery of active and durable materials for electrodes that ever-increasingly harness first principles calculations and machine learning. In addition a technoeconomic analysis of water electrolysis is included that allows an assessment of the extent to which a large-scale implementation of water splitting can help to combat climate change. This review article is intended to cross-pollinate and strengthen efforts from fundamental understanding to technical implementation and to improve the ‘junctions’ between the field’s physical chemists materials scientists and engineers as well as stimulate much-needed exchange among these groups on challenges encountered in the different domains.
Towards Net-zero Compatible Hydrogen from Steam Reformation - Techno-economic Analysis of Process Design Options
Dec 2022
Publication
Increased consumption of low-carbon hydrogen is prominent in the decarbonisation strategies of many jurisdictions. Yet prior studies assessing the current most prevalent production method steam reformation of natural gas (SRNG) have not sufficiently evaluated how process design decisions affect life cycle greenhouse gas (GHG) emissions. This techno-economic case study assesses cradle-to-gate emissions of hydrogen produced from SRNG with CO2 capture and storage (CCS) in British Columbia Canada. Four process configurations with amine-based CCS using existing technology and novel process designs are evaluated. We find that cradle-to-gate GHG emission intensity ranges from 0.7 to 2.7 kgCO2e/kgH2 – significantly lower than previous studies of SRNG with CCS and similar to the range of published estimates for hydrogen produced from renewable-powered electrolysis. The levelized cost of hydrogen (LCOH) in this study (US$1.1–1.3/kgH2) is significantly lower than published estimates for renewable-powered electrolysis.
Governing the UK’s Transition to Decarbonised Heating: Lessons from a Systematic Review of Past and Ongoing Heat Transitions
May 2020
Publication
According to the UK’s Committee on Climate Change the economically efficient achievement of Government’s legally-binding carbon-reduction target will require full decarbonisation of all heat in buildings and the decarbonisation of most industrial heat over the next 20 to 30 years (BEIS 2018). This goliath task is not unprecedented. Indeed the scale of this transition is similar to the UK’s former transition from coal to natural gas heating. Albeit the rate of transition away from natural gas will certainly need to be greater than the rate of the transition toward natural gas to achieve net zero greenhouse gas emissions by 2050.<br/><br/>At present Government’s commitment stands in sharp contrast with its inaction on heat decarbonisation to date. Under pressure to progress this agenda Government has charged the Clean Heat Directorate with the task of outlining the process for determining the UK’s long-term heat policy framework to be published in the ‘Roadmap for policy on heat decarbonisation’ in the summer of 2020 (BEIS 2017). This report resulting from one of six EPSRC-funded secondments is designed to support early thinking on the roadmap by answering the research question: How can ‘Transitions’ research informs the roadmap for governing the UK’s heating transition?<br/><br/>‘Transitions’ research is an interdisciplinary field of study within the Social Sciences and Humanities that investigates the co-evolution of social and technological systems (such as the UK heating system) and the dynamics by which fundamental change in these systems occur. To investigate what insights this area of research may hold for the governance of the UK’s heat transition a systematic literature review was conducted focusing specifically on past and ongoing heat transitions across Europe.<br/><br/>The review uncovered learnings about the role of path dependency; power and politics; complexity; cross-sector interactions; multi-level governance; and intermediaries in shaping non-linear transitions toward renewable heat. This report illustrates each learning with real-world examples from case studies undertaken by Transitions researchers and concludes with a long list of policy and process-oriented governance recommendations for the UK Government.
Condensed Phase Explosions Involving Liquid Hydrogen
Sep 2021
Publication
Liquid hydrogen may have an important role in the storage and transportation of hydrogen energy. It may also provide the best option for some users of hydrogen energy notably the aviation sector. In the 1960’s liquid hydrogen spillages in open uncongested conditions sometimes produced violent condensed phase explosions as well as the familiar gas phase flash and sustained pool fire. Testing showed that burning mixtures of LH2 and solid oxygen/nitrogen readily transitioned to detonation for oxygen concentrations in the solid phase at or above 50%. Such explosive events have been observed in more recent research work on LH2 spillage and the pressure effects could be significant in some accident scenarios. There is a need to understand how solids are produced following spillage and what factors determine the level of oxygen enrichment. This paper describes the physical processes involved in the accumulation of solids during a horizontal discharge at ground level based on observations made in a recent HSE test that led to a condensed phase explosion. Areas where solids accumulated but remained in intimate contact with LH2 are identified. The paper also includes a thermodynamic and fluid mechanical analysis of the condensation process that includes the calculation of densities of mixtures of LH2 and air in different proportions. When the difference in flow speed between air and underlying LH2 is low a stable condensation layer can develop above the liquid where the temperature is just under the initial condensation point of air allowing sustained oxygen enrichment of condensate.
Power-to-Gas: Electrolysis and Methanation Status Review
Jun 2019
Publication
This review gives a worldwide overview on Power-to-Gas projects producing hydrogen or renewable substitute natural gas focusing projects in central Europe. It deepens and completes the content of previous reviews by including hitherto unreviewed projects and by combining project names with details such as plant location. It is based on data from 153 completed recent and planned projects since 1988 which were evaluated with regards to plant allocation installed power development plant size shares and amounts of hydrogen or substitute natural gas producing examinations and product utilization phases. Cost development for electrolysis and carbon dioxide methanation was analyzed and a projection until 2030 is given with an outlook to 2050.<br/>The results show substantial cost reductions for electrolysis as well as for methanation during the recent years and a further price decline to less than 500 euro per kilowatt electric power input for both technologies until 2050 is estimated if cost projection follows the current trend. Most of the projects examined are located in Germany Denmark the United States of America and Canada. Following an exponential global trend to increase installed power today's Power-to-Gas applications are operated at about 39 megawatt. Hydrogen and substitute natural gas were investigated on equal terms concerning the number of projects.
A Brief Review of Hydrogen Production Methods and Their Challenges
Jan 2023
Publication
Hydrogen is emerging as a new energy vector outside of its traditional role and gaining more recognition internationally as a viable fuel route. This review paper offers a crisp analysis of the most recent developments in hydrogen production techniques using conventional and renewable energy sources in addition to key challenges in the production of Hydrogen. Among the most potential renewable energy sources for hydrogen production are solar and wind. The production of H2 from renewable sources derived from agricultural or other waste streams increases the flexibility and improves the economics of distributed and semi-centralized reforming with little or no net greenhouse gas emissions. Water electrolysis equipment driven by off-grid solar or wind energy can also be employed in remote areas that are away from the grid. Each H2 manufacturing technique has technological challenges. These challenges include feedstock type conversion efficiency and the need for the safe integration of H2 production systems with H2 purification and storage technologies.
Investigation of an Intensified Thermo-Chemical Experimental Set-Up for Hydrogen Production from Biomass: Gasification Process Performance—Part I
Jun 2021
Publication
Biomass gasification for energy purposes has several advantages such as the mitigation of global warming and national energy independency. In the present work the data from an innovative and intensified steam/oxygen biomass gasification process integrating a gas filtration step directly inside the reactor are presented. The produced gas at the outlet of the 1 MWth gasification pilot plant was analysed in terms of its main gaseous products (hydrogen carbon monoxide carbon dioxide and methane) and contaminants. Experimental test sets were carried out at 0.25–0.28 Equivalence Ratio (ER) 0.4–0.5 Steam/Biomass (S/B) and 780–850 °C gasification temperature. Almond shells were selected as biomass feedstock and supplied to the reactor at approximately 120 and 150 kgdry/h. Based on the collected data the in-vessel filtration system showed a dust removal efficiency higher than 99%-wt. A gas yield of 1.2 Nm3dry/kgdaf and a producer gas with a dry composition of 27–33%v H2 23–29%v CO 31–36%v CO2 9–11%v CH4 and light hydrocarbons lower than 1%v were also observed. Correspondingly a Low Heating Value (LHV) of 10.3–10.9 MJ/Nm3dry and a cold gas efficiency (CGE) up to 75% were estimated. Overall the collected data allowed for the assessment of the preliminary performances of the intensified gasification process and provided the data to validate a simulative model developed through Aspen Plus software.
Effects of Thermomechanical Processing on Hydrogen Embrittlement Properties of Ultrahigh-Strength TRIP-Aided Bainitic Ferrite Steels
Jan 2022
Publication
The effects of thermomechanical processing on the microstructure and hydrogen embrittlement properties of ultrahigh-strength low-alloy transformation-induced plasticity (TRIP)-aided bainitic ferrite (TBF) steels were investigated to apply to automobile forging parts such as engine and drivetrain parts. The hydrogen embrittlement properties were evaluated by conducting conventional tensile tests after hydrogen charging and constant load four-point bending tests with hydrogen charging. The 0.4 mass%C-TBF steel achieved refinement of the microstructure improved retained austenite characteristics and strengthening owing to thermomechanical processing. This might be attributed to dynamic and static recrystallizations during thermomechanical processing in TBF steels. Moreover the hydrogen embrittlement resistances were improved by the thermomechanical processing in TBF steels. This might be caused by the refinement of the microstructure an increase in the stability of the retained austenite and low hydrogen absorption of the thermomechanically processed TBF steels.
Shipping Australian Sunshine: Liquid Renewable Green Fuel Export
Dec 2022
Publication
Renewable green fuels (RGF) such as hydrogen are the global energy future. Air pollution is compounded with climate change as the emissions driving both development problems come largely from the same source of fossil fuel burning. As an energy exporter Australian energy export dominates the total energy production and the RGF has become central to the current proposal of Australian government to reach net zero emission. The hydrogen production from solar panels only on 3% of Australia's land area could compensate 10 times of Germany's non-electricity energy consumption. In the unique geographic position Australia's RGF export attracts significant costs for long distance onboard storage and shipping. While the cost reduction of RGF production relies on technological advancement which needs a long time the storage and shipping costs must be minimised for Australia to remain competitive in the global energy market. The present review concentrates on Australian export pathways of lifecycles of liquid renewable green fuels including renewable liquified hydrogen (LH2) liquified methane (LCH4) ammonia (NH3) and methanol (CH3OH) as liquid RGF have the advantages of adopting the existing infrastructure. This review compares the advantages and disadvantages of discussed renewable energy carriers. It is found that the cost of LH2 pathway can be acceptable for shipping distance of up to 7000 km (Asian countries such as Japan) but ammonia (NH3) or methanol (CH3OH) pathways may be more cost effective for shipping distance above 7000 km for European counties such as Germany. These observations suggest the proper fuel forms to fulfill the requirements to different customers and hence will highlight Australia's position as one of major exporters of renewable energy in the future. Detailed techno-economic analysis is worth to be done for supplying more quantitative results.
Everything About Hydrogen Podcast: M&A in the Modern Hydrogen Economy
Sep 2021
Publication
This week we have Christopher Jackson in the hot seat as he catches up with BayoTech CEO Mo Vargas and BayoTech’s new President Michael Koonce to discuss the acquisition of IGX Group. Mergers & Acquisition activity has been growing in the hydrogen space with commentators suggesting the market is maturing faster than expected and customers seeking more integrated solutions. In this episode we look at the IGX acquisition by BayoTech and ask why the deal made sense what it means for the market and other participants and what listeners can learn from the deal to foreshadow future activity.
The podcast can be found on their website
The podcast can be found on their website
Techno-economic Assessment of a Hybrid Off-grid DC System for Combined Heat and Power Generation in Remote Islands
Mar 2019
Publication
Hybrid renewable energy systems that combine heat and electricity generation is an achievable option for remote areas where grid is uneconomical to extend. In this study a renewable-based system was designed to satisfy the electrical and thermal demands of a remote household in an off-grid Greek island. A hybrid DC system consisted of a combination of photovoltaic modules wind turbine electrolyzer-hydrogen tank fuel cell and batteries were analysed using HOMER Pro software. Based on the optimal obtained system it is found that such a system can satisfy both electrical and thermal load demand throughout the year in a reliable manner.
Is Hydrogen the Future of Nuclear Energy?
Jan 2008
Publication
The traditionally held belief is that the future of nuclear energy is electricity production. However another possible future exists: nuclear energy used primarily for the production of hydrogen. The hydrogen in turn would be used to meet our demands for transport fuels (including liquid fuels) materials such as steel and fertilizer and peak-load electricity production. Hydrogen would become the replacement for fossil fuels in these applications that consume more than half the world’s energy. Such a future would follow from several factors: (a) concerns about climatic change that limit the use of fossil fuels (b) the fundamental technological differences between hydrogen and electricity that may preferentially couple different primary energy sources with either hydrogen or electricity and (c) the potential for other technologies to competitively produce electricity but not hydrogen. Electricity (movement of electrons) is not fundamentally a large-scale centralized technology that requires centralized methods of production distribution or use. In contrast hydrogen (movement of atoms) is intrinsically a large-scale centralized technology. The large-scale centralized characteristics of nuclear energy as a primary energy source hydrogen production systems and hydrogen storage systems naturally couple these technologies. This connection suggests that serious consideration be given to hydrogen as the ultimate product of nuclear energy and that nuclear systems be designed explicitly for hydrogen production.
Artificial Neural Networks for Predicting Hydrogen Production in Catalytic Dry Reforming: A Systematic Review
May 2021
Publication
Dry reforming of hydrocarbons alcohols and biological compounds is one of the most promising and effective avenues to increase hydrogen (H2 ) production. Catalytic dry reforming is used to facilitate the reforming process. The most popular catalysts for dry reforming are Ni-based catalysts. Due to their inactivation at high temperatures these catalysts need to use metal supports which have received special attention from researchers in recent years. Due to the existence of a wide range of metal supports and the need for accurate detection of higher H2 production in this study a systematic review and meta-analysis using ANNs were conducted to assess the hydrogen production by various catalysts in the dry reforming process. The Scopus Embase and Web of Science databases were investigated to retrieve the related articles from 1 January 2000 until 20 January 2021. Forty-seven articles containing 100 studies were included. To determine optimal models for three target factors (hydrocarbon conversion hydrogen yield and stability test time) artificial neural networks (ANNs) combined with differential evolution (DE) were applied. The best models obtained had an average relative error for the testing data of 0.52% for conversion 3.36% for stability and 0.03% for yield. These small differences between experimental results and predictions indicate a good generalization capability.
Everything About Hydrogen Podcast: Hydrogen from Waste
Mar 2021
Publication
On this episode of EAH the team is joined by Tim Yeo Chairman of Powerhouse Energy to talk about the work they are doing in the waste-to-energy space and how they see the sector evolving in the coming years.
The podcast can be found on their website
The podcast can be found on their website
Risk Assessment of the Large-Scale Hydrogen Storage in Salt Caverns
May 2021
Publication
Salt caverns are accepted as an ideal solution for high-pressure hydrogen storage. As well as considering the numerous benefits of the realization of underground hydrogen storage (UHS) such as high energy densities low leakage rates and big storage volumes risk analysis of UHS is a required step for assessing the suitability of this technology. In this work a preliminary quantitative risk assessment (QRA) was performed by starting from the worst-case scenario: rupture at the ground of the riser pipe from the salt cavern to the ground. The influence of hydrogen contamination by bacterial metabolism was studied considering the composition of the gas contained in the salt caverns as time variable. A bow-tie analysis was used to highlight all the possible causes (basic events) as well as the outcomes (jet fire unconfined vapor cloud explosion (UVCE) toxic chemical release) and then consequence and risk analyses were performed. The results showed that a UVCE is the most frequent outcome but its effect zone decreases with time due to the hydrogen contamination and the higher contents of methane and hydrogen sulfide.
Large-scale Stationary Hydrogen Storage via Liquid Organic Hydrogen Carriers
Aug 2021
Publication
Large-scale stationary hydrogen storage is critical if hydrogen is to fulfill its promise as a global energy carrier. While densified storage via compressed gas and liquid hydrogen is currently the dominant approach liquid organic molecules have emerged as a favorable storage medium because of their desirable properties such as low cost and compatibility with existing fuel transport infrastructure. This perspective article analytically investigates hydrogenation systems' technical and economic prospects using liquid organic hydrogen carriers (LOHCs) to store hydrogen at a large scale compared to densified storage technologies and circular hydrogen carriers (mainly ammonia and methanol). Our analysis of major system components indicates that the capital cost for liquid hydrogen storage is more than two times that for the gaseous approach and four times that for the LOHC approach. Ammonia and methanol could be attractive options as hydrogen carriers at a large scale because of their compatibility with existing liquid fuel infrastructure. However their synthesis and decomposition are energy and capital intensive compared to LOHCs. Together with other properties such as safety these factors make LOHCs a possible option for large-scale stationary hydrogen storage. In addition hydrogen transportation via various approaches is briefly discussed. We end our discussions by identifying important directions for future research on LOHCs.
Techno-Economic Feasibility of a Solar-Wind-Fuel Cell Energy System in Duqm, Oman
Jul 2022
Publication
Duqm is located in the Al Wasta Governorate in Oman and is currently fed by 10 diesel generators with a total capacity of around 76 MW and other rental power sources with a size of 18 MW. To make the electric power supply come completely from renewables one novel solution is to replace the diesel with hydrogen. The extra energy coming from the PV-wind system can be utilized to produce green hydrogen that will be utilized by the fuel cell. Measured data of solar insolation hourly wind speeds and hourly load consumption are used in the proposed system. Finding an ideal configuration that can match the load demand and be suitable from an economic and environmental point of view was the main objective of this research. The Hybrid Optimization Model for Multiple Energy Resources (HOMER Pro) microgrid software was used to evaluate the technical and financial performance. The findings demonstrated that the suggested hybrid system (PV-wind-fuel cell) will remove CO2 emissions at a cost of energy (COE) of USD 0.436/kWh and will reduce noise. With a total CO2 emission of 205676830 kg/year the levelized cost of energy for the current system is USD 0.196/kWh. The levelized cost for the diesel system will rise to USD 0.243/kWh when taking 100 US dollars per ton of CO2 into account. Due to system advantages the results showed that using solar wind and fuel cells is the most practical and cost-effective technique. The results of this research illustrated the feasibility and effectiveness of utilizing wind and solar resources for both hydrogen and energy production and also suggested that hydrogen is a more cost-effective long-term energy storage option than batteries.
Hydrogen Fuel for Future Mobility: Challenges and Future Aspects
Jul 2022
Publication
Nowadays the combustion of fossil fuels for transportation has a major negative impact on the environment. All nations are concerned with environmental safety and the regulation of pollution motivating researchers across the world to find an alternate transportation fuel. The transition of the transportation sector towards sustainability for environmental safety can be achieved by the manifestation and commercialization of clean hydrogen fuel. Hydrogen fuel for sustainable mobility has its own effectiveness in terms of its generation and refueling processes. As the fuel requirement of vehicles cannot be anticipated because it depends on its utilization choosing hydrogen refueling and onboard generation can be a point of major concern. This review article describes the present status of hydrogen fuel utilization with a particular focus on the transportation industry. The advantages of onboard hydrogen generation and refueling hydrogen for internal combustion are discussed. In terms of performance affordability and lifetime onboard hydrogen-generating subsystems must compete with what automobile manufacturers and consumers have seen in modern vehicles to date. In internal combustion engines hydrogen has various benefits in terms of combustive properties but it needs a careful engine design to avoid anomalous combustion which is a major difficulty with hydrogen engines. Automobile makers and buyers will not invest in fuel cell technology until the technologies that make up the various components of a fuel cell automobile have advanced to acceptable levels of cost performance reliability durability and safety. Above all a substantial advancement in the fuel cell stack is required.
A Policy Review of Green Hydrogen Economy in Southern Africa
Nov 2021
Publication
Renewable energy and clean energy have been on the global agenda for energy transition for quite a long time but recently gained strong momentum especially with the anticipated depletion of fossil fuels alongside increasing environmental degradation from their exploitation and the changing climate caused by their excessive carbon emissions. Despite this Africa’s pursuit to transition to a green economy using renewable energy resources still faces constraints that hamper further development and commercialization. These may include socio-economic technical political financial and institutional policy framework barriers. Although hydrogen demand is still low in Southern Africa the region can meet the global demands for green hydrogen as a major supplier because of its enormous renewable energy resource-base. This article reviews existing renewable energy resources and hydrogen energy policies in the Southern African Development Community (SADC). The significance of this review is that it explores how clean energy technologies that utilize renewable energy resources address the United Nations sustainable development goals (UN SDGs) and identifies the hydrogen energy policy gaps. This review further presents policy options and recommends approaches to enhance hydrogen energy production and ramp the energy transition from a fossil fuel-based economy to a hydrogen energy-based economy in Southern Africa. Concisely the transition can be achieved if the existing hydrogen energy policy framework gap is narrowed by formulating policies that are specific to hydrogen development in each country with the associated economic benefits of hydrogen energy clearly outlined.
Comprehensive Analysis of the Combustion of Low Carbon Fuels (Hydrogen, Methane and Coke Oven Gas) in a Spark Ignition Engine through CFD Modeling
Nov 2021
Publication
The use of low carbon fuels (LCFs) in internal combustion engines is a promising alternative to reduce pollution while achieving high performance through the conversion of the high energy content of the fuels into mechanical energy. However optimizing the engine design requires deep knowledge of the complex phenomena involved in combustion that depend on the operating conditions and the fuel employed. In this work computational fluid dynamics (CFD) simulation tools have been used to get insight into the performance of a Volkswagen Polo 1.4L port-fuel injection spark ignition engine that has been fueled with three different LCFs coke oven gas (COG) a gaseous by-product of coke manufacture H2 and CH4. The comparison is made in terms of power pressure temperature heat release flame growth speed emissions and volumetric efficiency. Simulations in Ansys® Forte® were validated with experiments at the same operating conditions with optimal spark advance wide open throttle a wide range of engine speed (2000–5000 rpm) and air-fuel ratio (λ) between 1 and 2. A sensitivity analysis of spark timing has been added to assess its impact on combustion variables. COG with intermediate flame growth speed produced the greatest power values but with lower pressure and temperature values at λ = 1.5 reducing the emissions of NO and the wall heat transfer. The useful energy released with COG was up to 16.5% and 5.1% higher than CH4 and H2 respectively. At richer and leaner mixtures (λ = 1 and λ = 2) similar performances were obtained compared to CH4 and H2 combining advantages of both pure fuels and widening the λ operation range without abnormal combustion. Therefore suitable management of the operating conditions maximizes the conversion of the waste stream fuel energy into useful energy while limiting emissions.
Energy Innovation Needs Assessment: Overview
Nov 2019
Publication
This project provides evidence to identify the key innovation needs across the UK’s energy system to inform the prioritisation of public sector investment in low-carbon innovation including any future phases of the Department for Business Energy & Industrial Strategy (BEIS) Energy Innovation1 Programme. The BEIS Energy Innovation Programme aims to accelerate the commercialisation of innovative clean energy technologies and processes into the 2020s and 2030s. The current Programme with a budget of £505 million from 2015-2021 consists of six themes and invests in smart systems industry & CCS (Carbon Capture and Storage) the built environment nuclear renewables and support for energy entrepreneurs and green financing.
Vivid Economics was contracted to lead a consortium with technical expertise in each of the Energy Innovation Needs Assessment (EINA) priority areas. The programme relied on evidence from a programme of workshops with over 180 participants energy system modelling and detailed technical advice. Partners include the Carbon Trust E4tech Imperial College London and Fraser-Nash. The Energy Systems Catapult (ESC) provided analytical evidence using their Energy System Modelling Environment (ESME) to support an early pre-screening of technologies.
Innovations have been prioritised where there is a strong case for UK Government investment. The prioritisation in this report is based on evidence of the potential benefits to the UK via a lower cost energy system and larger export markets. We also consider whether there is a need for UK Government intervention in addition to private and international efforts.
A distinctive feature of this project is its focus on innovation that benefits the whole energy system. Internationally there are other efforts attempting to answer the question of where to target resources to maximise benefits from innovation2. In selecting priorities we identify innovations that can unlock value across electricity heat transport sectors and the rest of the economy.
Vivid Economics was contracted to lead a consortium with technical expertise in each of the Energy Innovation Needs Assessment (EINA) priority areas. The programme relied on evidence from a programme of workshops with over 180 participants energy system modelling and detailed technical advice. Partners include the Carbon Trust E4tech Imperial College London and Fraser-Nash. The Energy Systems Catapult (ESC) provided analytical evidence using their Energy System Modelling Environment (ESME) to support an early pre-screening of technologies.
Innovations have been prioritised where there is a strong case for UK Government investment. The prioritisation in this report is based on evidence of the potential benefits to the UK via a lower cost energy system and larger export markets. We also consider whether there is a need for UK Government intervention in addition to private and international efforts.
A distinctive feature of this project is its focus on innovation that benefits the whole energy system. Internationally there are other efforts attempting to answer the question of where to target resources to maximise benefits from innovation2. In selecting priorities we identify innovations that can unlock value across electricity heat transport sectors and the rest of the economy.
Power-to-hydrogen as Seasonal Energy Storage: An Uncertainty Analysis for Optimal Design of Low-carbon Multi-energy Systems
Jun 2020
Publication
This study analyzes the factors leading to the deployment of Power-to-Hydrogen (PtH2) within the optimal design of district-scale Multi-Energy Systems (MES). To this end we utilize an optimization framework based on a mixed integer linear program that selects sizes and operates technologies in the MES to satisfy electric and thermal demands while minimizing annual costs and CO2 emissions. We conduct a comprehensive uncertainty analysis that encompasses the entire set of technology (e.g. cost efficiency lifetime) and context (e.g. economic policy grid carbon footprint) input parameters as well as various climate-referenced districts (e.g. environmental data and energy demands) at a European-scope.
Minimum-emissions MES with large amounts of renewable energy generation and high ratios of seasonal thermal-to-electrical demand optimally achieve zero operational CO2 emissions by utilizing PtH2 seasonally to offset the long-term mismatch between renewable generation and energy demand. PtH2 is only used to abate the last 5–10% emissions and it is installed along with a large battery capacity to maximize renewable self-consumption and completely electrify thermal demand with heat pumps and fuel cells. However this incurs additional cost. Additionally we show that ‘traditional’ MES comprised of renewables and short-term energy storage are able to decrease emissions by 90% with manageable cost increases.
The impact of uncertainty on the optimal system design reveals that the most influential parameter for PtH2 implementation is (1) heat pump efficiency as it is the main competitor in providing renewable-powered heat in winter. Further battery (2) capital cost and (3) lifetime prove to be significant as the competing electrical energy storage technology. In the face of policy uncertainties a CO2 tax shows large potential to reduce emissions in district MES without cost implications. The results illustrate the importance of capturing the dynamics and uncertainties of short- and long-term energy storage technologies for assessing cost and CO2 emissions in optimal MES designs over districts with different geographical scopes.
Minimum-emissions MES with large amounts of renewable energy generation and high ratios of seasonal thermal-to-electrical demand optimally achieve zero operational CO2 emissions by utilizing PtH2 seasonally to offset the long-term mismatch between renewable generation and energy demand. PtH2 is only used to abate the last 5–10% emissions and it is installed along with a large battery capacity to maximize renewable self-consumption and completely electrify thermal demand with heat pumps and fuel cells. However this incurs additional cost. Additionally we show that ‘traditional’ MES comprised of renewables and short-term energy storage are able to decrease emissions by 90% with manageable cost increases.
The impact of uncertainty on the optimal system design reveals that the most influential parameter for PtH2 implementation is (1) heat pump efficiency as it is the main competitor in providing renewable-powered heat in winter. Further battery (2) capital cost and (3) lifetime prove to be significant as the competing electrical energy storage technology. In the face of policy uncertainties a CO2 tax shows large potential to reduce emissions in district MES without cost implications. The results illustrate the importance of capturing the dynamics and uncertainties of short- and long-term energy storage technologies for assessing cost and CO2 emissions in optimal MES designs over districts with different geographical scopes.
Everything About Hydrogen Podcast: Is Small the Perfect Answer for SMRs?
Jun 2020
Publication
On this week’s episode the team discuss the appeal of modular reforming of biogas and natural gas with Mo Vargas from Bayotech. The company use a proprietary modular reformer technology to help provide low cost decentralise hydrogen production units for onsite demand at various scales using biogas waste gases and natural gas with carbon capture. With large scale steam methane reforming accounting for 95% of hydrogen production in major markets like the US and Europe today the team dive into the good the bad and the unusual considerations behind the growing international demand for modular methane reforming technologies and how Bayotech see the transition from a CO2 intensive process today to a net zero emission future. All this and more on the show!
The podcast can be found on their website
The podcast can be found on their website
Climate Change Impacts of E-fuels for Aviation in Europe Under Present-day Conditions and Future Policy Scenarios
Jan 2023
Publication
‘E-fuels’ or ‘synthetic fuels’ are hydrocarbon fuels synthesized from hydrogen (H2) and carbon dioxide (CO2) where H2 can be produced via electrolysis of water or steam reforming of natural gas and CO2 is captured from the combustion of a fossil or biogenic source or directly from the atmosphere. E-fuels are drop-in substitutes for fossil fuels but their climate change mitigation benefits are largely unclear. This study evaluates the climate change impacts of e-fuels for aviation by combining different sources of CO2 and H2 up to 2050 under two contrasting policy scenarios. The analysis includes different climate metrics and the effects of near-term climate forcers which are particularly relevant for the aviation sector. Results are produced for European average conditions and for Poland and Norway two countries with high and low emission intensity from their electricity production mix. E-fuels can either have higher or lower climate change impacts than fossil fuels depending on multiple factors such as in order of importance the electricity mix the origin of CO2 the technology for H2 production and the electrolyzer efficiency. The climate benefits are generally higher for e-fuels produced from CO2 of biogenic origin while e-fuels produced from CO2 from direct air capture or fossil fuel combustion require countries with clean electricity to outperform fossil fuels. Synthetic fuels produced from H2 derived from natural gas have higher impacts than fossil fuels even when coupled with carbon capture and storage if CO2 is sourced from fossil fuels or the atmosphere. Climate change impacts of e-fuels improve in the future and they can all achieve considerable climate change mitigation in 2050 relative to fossil jet fuel provided that strict climate policy measures are implemented to decarbonize the electricity sector. Under reduced policy efforts future climate impacts in 2050 of e-fuels from atmospheric or fossil CO2 are still higher than those of fossil jet fuels with an average European electricity mix. This study shows the conditions to maximize the climate change mitigation benefits of e-fuels which essentially depend on progressive decarbonization of the electricity sector and on reduced use of CO2 sourced from fossil fuels.
Thermodynamic Performance Comparison of Various Energy Storage Systems from Source-to-electricity for Renewable Energy Resources
Dec 2020
Publication
This study discusses and thermodynamically analyzes several energy storage systems namely; pumped hydro compressed air hot water storage molten salt thermal storage hydrogen ammonia lithium-ion battery Zn-air battery redox flow battery reversible fuel cells supercapacitors and superconducting magnetic storage through the first and second law of thermodynamics. By fixing an electrical output of 100 kW for all systems the energy efficiencies obtained for the considered energy storage methods vary between 10.9% and 74.6% whereas the exergy efficiencies range between 23.1% and 71.9%. The exergy destruction rates are also calculated for each system ranging from 1.640 kW to 356 kW. The highest destruction rate is obtained for the solar-driven molten salt thermal energy storage system since it includes thermal energy conversion via the heliostat field. Furthermore the roundtrip efficiencies for the electrochemical and electromagnetic storage systems are compared with the analyzed systems ranging from 58% to 94%. Renewable sources (solar wind ocean current biomass and geothermal) energy conversion efficiencies are also considered for the final round-trip performances. The molten salt and hot water systems are applicable to solar geothermal and biomass. The highest source-to-electricity efficiency is obtained for the super magnetic storage with 37.6% when using wind ocean current and biomass sources.
How to Give a renewed Chance to Natural Gas as Feed for the Production of Hydrogen: Electric MSR Coupled with CO2 Mineralization
Sep 2021
Publication
Recent years have seen a growing interest in water electrolysis as a way to store renewable electric energy into chemical energy through hydrogen production. However today the share of renewable energy is still limited and there is the need to have a continuous use of H2 for industrial chemicals applications. Firstly the paper discusses the use of electrolysis - connected to a conventional grid - for a continuous H2 production in terms of associated CO2 emissions and compares such emissions with conventional methane steam reforming (MSR). Therefore it explores the possibility to use electrical methane steam reforming (eMSR) as a way to reduce the CO2 emissions. As a way to have zero emissions carbon mineralization of CO2 is coupled - instead of in-situ carbon capture and storage technology (CCS) - to eMSR; associated relevant cost of production is evaluated for different scenarios. It appears that to minimize such production cost carbonate minerals must be reused in the making of other industrial products since the amount of carbonates generated by the process is quite significant.
Impact Assessment of Hydrogen on Transmission Pipeline BPDs in IGEM/TD/1
Jul 2021
Publication
As part of the LTS Futures HyTechnical project IGEM requested that DNV GL undertake an assessment of the possible impact of hydrogen transmission on BPDs to support the development of supplements to the existing suite of natural gas standards to accommodate the possible future use of hydrogen. The current state of knowledge of the behaviour of large scale high pressure hydrogen releases is limited in comparison with the considerable body of data from research and operational experience of natural gas but is adequate to undertake an impact assessment to take account of the different gas outflow and fire characteristics of 100% hydrogen vs. natural gas.<br/>Calculations of the BPDs for 100% hydrogen pipeline fires on an equivalent basis to those in IGEM/TD/1 for natural gas have been performed with a degree of confidence in the results and demonstrated that the equivalent BPDs for 100% hydrogen are approximately 10% smaller than for natural gas. The results are presented graphically in this report.<br/>However hydrogen introduces the potential for substantially higher overpressures than natural gas due to the higher flame speed and wider flammable limits if delayed ignition is a credible event. The overpressure estimates presented in this report are intended to be scoping calculations to put the likely overpressures into context. The results suggest that significant overpressures are possible at the BPDs but there is a lack of evidence to support the estimation of the overpressures following delayed ignition of a large turbulent hydrogen release in the open (in contrast to explosions in confined or congested regions) and there is a high degree of uncertainty in the predictions presented here. It is therefore recommended that large scale pipeline rupture experiments are performed similar to those undertaken previously for hydrogen natural gas and natural gas/hydrogen mixtures but with ignition engineered to take place after a short delay in order to measure the overpressures and provide the means to validate or refine the predictions made.<br/>The analysis has highlighted limitations in the original method of calculating BPDs in IGEM/TD/1 which reflects the techniques available at the time approximately 40 years ago. Since then understanding of the hazards from pipeline failures and the ability to model the consequences and predict the associated risks to people in the surrounding area have advanced very considerably facilitated by software tools and documented in standards such as IGEM/TD/2. These methods allow the highly transient nature of a high pressure gas pipeline rupture release to be modelled more accurately and for the thermal effects of fires on people and buildings to be calculated taking account of the time-varying thermal dose.<br/>For these reasons a simple comparison of the possible overpressure effects of delayed ignition of a 100% hydrogen release at the BPDs can be misleading and implies that the overpressure hazards could be more severe than those for fires which may not be the case. Example calculations have been performed for a representative pipeline case which indicate that using current methods the predicted thermal hazard distances for 100% hydrogen pipeline fires (house burning and escape for people) are substantially greater than those estimated for overpressures following delayed ignition for similar levels of vulnerability. This report addresses buried pipelines only – the potential for more severe explosion overpressure effects for hydrogen releases may be more significant for Above Ground Installations (AGIs) especially where congestion or confinement may be present. It is recommended that similar studies are conducted to quantify the effect of hydrogen conversion on the consequences and risks associated with hydrogen releases at AGIs.<br/>Finally it is stressed that the analysis in this report does not consider the relative risks for 100% hydrogen and the equivalent natural gas pipelines. There remain uncertainties in the failure frequencies for steel pipelines transporting hydrogen and particularly the probability of immediate and delayed ignition. The likelihood of delayed ignition of a large turbulent high pressure hydrogen gas pipeline rupture release may be very low due to the wider flammability limits and lower minimum ignition energy for hydrogen compared with natural gas. Additional research is currently ongoing or planned to address the gaps in knowledge for 100% hydrogen which should allow more robust comparisons of the relative risks to be made in the future.
Observation of the Hydrogen Dispersion by Using Raman Scattering Measurement and Increase of Measurable Distance
Sep 2017
Publication
Preparing for the arrival of the hydrogen society it is necessary to develop suitable sensors to use hydrogen safely. There are many methods to know the hydrogen concentration by using conventional sensors but it is difficult to know the behavior of hydrogen gas from long distance. This study measured hydrogen dispersion by using Raman scattering light. Generally some delays occur when using conventional sensors but there are almost no delays by using the new Raman sensor. In the experiments 6mm & 1mm diameter holes are used as a spout nozzle to change initial velocities. To ensure the result a special sheets are used which turns transparent when it detected hydrogen and visualized the hydrogen behaviour. As a result the behaviour of the hydrogen gas in the small container was observed. In addition measurable distance is increased by the improvement of the device.
Oxford Energy Podcast – Saudi Aramco’s Perspectives on Hydrogen: Opportunities and Challenges
Jun 2021
Publication
As the world’s largest integrated energy and chemicals company Saudi Aramco continues to invest in technologies and innovative business models to enable the sustainable use of hydrocarbon resources across the value chain. In this podcast David Ledesma discusses with Yasser Mufti Vice President Strategy & Market Analysis Saudi Aramco about Saudi Aramco’s perspectives on hydrogen its opportunities and challenges. This wide-ranging interview discusses Saudi Aramco’s investment in new technologies and the sustainable use of its hydrocarbon resources before addressing the role of hydrogen in achieving a low emissions economy possible business models and the barriers to achieving hydrogen’s growth. The podcast then moves on to discuss ammonia carbon capture utilisation and storage finishing up with a forward-looking perspective on the vision for Saudi Aramco asking how will the company look in 2050 and specifically whether it will still be a hydrocarbon company?
The podcast can be found on their website
The podcast can be found on their website
Heat Pumps for Space Heating and Domestic Hot Water Production in Residential Buildings, an Environmental Comparison in a Present and Future Scenario
Nov 2022
Publication
The hydrogen vector stands as a potentially important tool to achieve the decarbonization of the energy sector. It represents an option to store the periodic excesses of energy generation from renewable electrical sources to be used as it is as a substitute for fossil fuels in some applications or reconverted into electricity when needed. In this context hydrogen can significantly decarbonize the building sector as an alternative fuel for gas-driven devices. Along with hydrogen the European strategic vision indicates the electrification of heat among the main energy transition pathways. The potential environmental benefits achievable from renewable hydrogen in thermally-driven appliances and the electrification of residential heat through electric heat pumps were evaluated and compared in this work. The novelty of the research consists of a consequential comparative life cycle assessment (16 impact categories) evaluation for three buildings (old old retrofitted and new) supplied by three different appliances (condensing boiler gas absorption heat pump and electric heat pump) never investigated before. The energy transition was evaluated for 2020 and 2030 scenarios considering the impact of gaseous fuels (natural gas and European green hydrogen) and electricity based on the pathway of the European electricity grid (27 European member states plus the United Kingdom). The results allowed to compare the environmental profile in deterministic and stochastic approaches and confirm if the increase of renewables reduces the impact in the operational phase of the appliances. The results demonstrate that despite the increased renewable share the use phase remains the most significant for both temporal scenarios contributing to 91% of the environmental profile. Despite the higher footprint in 2020 compared to the electric heat pump (198–200 vs. 170–196 gCO2eq/kWhth) the gas absorption heat pump offered a lower environmental profile than the others in all the scenarios analyzed.
Cost Benefits of Optimizing Hydrogen Storage and Methanation Capacities for Power-to-Gas Plants in Dynamic Operation
Oct 2019
Publication
Power-to-Gas technologies offer a promising approach for converting renewable electricity into a molecular form (fuel) to serve the energy demands of non-electric energy applications in all end-use sectors. The technologies have been broadly developed and are at the edge of a mass roll-out. The barriers that Power-to-Gas faces are no longer technical but are foremost regulatory and economic. This study focuses on a Power-to-Gas pathway where electricity is first converted in a water electrolyzer into hydrogen which is then synthetized with carbon dioxide to produce synthetic natural gas. A key aspect of this pathway is that an intermittent electricity supply could be used which could reduce the amount of electricity curtailment from renewable energy generation. Interim storages would then be necessary to decouple the synthesized part from hydrogen production to enable (I) longer continuous operation cycles for the methanation reactor and (II) increased annual full-load hours leading to an overall reduction in gas production costs. This work optimizes a Power-to-Gas plant configuration with respect to the cost benefits using a Monte Carlo-based simulation tool. The results indicate potential cost reductions of up to 17% in synthetic natural gas production by implementing well-balanced components and interim storages. This study also evaluates three different power sources which differ greatly in their optimal system configuration. Results from time-resolved simulations and sensitivity analyses for different plant designs and electricity sources are discussed with respect to technical and economic implications so as to facilitate a plant design process for decision makers.
HydroGenerally - Episode 5: Hydrogen for Glass Production
May 2022
Publication
In this fifth episode Steffan Eldred and Neelam Mughal from Innovate UK KTN discuss how the glass industry is driving new hydrogen developments and research and explore the hydrogen transition opportunities and challenges in this sector alongside their special guest Rob Ireson Innovation and Partnerships Manager at Glass Futures Ltd.
The podcast can be found on their website
The podcast can be found on their website
Research on Multi-Objective Energy Management of Renewable Energy Power Plant with Electrolytic Hydrogen Production
Mar 2024
Publication
This study focuses on a renewable energy power plant equipped with electrolytic hydrogen production system aiming to optimize energy management to smooth renewable energy generation fluctuations participate in peak shaving auxiliary services and increase the absorption space for renewable energy. A multi-objective energy management model and corresponding algorithms were developed incorporating considerations of cost pricing and the operational constraints of a renewable energy generating unit and electrolytic hydrogen production system. By introducing uncertain programming the uncertainty issues associated with renewable energy output were successfully addressed and an improved particle swarm optimization algorithm was employed for solving. A simulation system established on the Matlab platform verified the effectiveness of the model and algorithms demonstrating that this approach can effectively meet the demands of the electricity market while enhancing the utilization rate of renewable energies.
Electrification Versus Hydrogen for UK Road Freight: Conclusions from a Systems Analysis of Transport Energy Transitions
Mar 2022
Publication
Collectively the UK investment in transport decarbonisation is greater than £27B from government for incentivising zero-emission vehicles as part of an urgent response to decarbonise the transport sector. The investments made must facilitate a transition to a long-term solution. The success relies on coordinating and testing the evolution of both the energy and transport systems this avoids the risk of unforeseen consequences in both systems and therefore de-risks investment Here we present a semiquantitative energy and transport system analysis for UK road freight focusing on two primary investment areas for nation-wide decarbonisation namely electrification and hydrogen propulsion. Our study assembles and assesses the potential roadblocks of these energy systems into a concise record and considers the infrastructure in relation to all other components within the energy system. It highlights that for system-wide success and resilience a hydrogen system must overcome hydrogen production and distribution barriers whereas an electric system needs to optimise storage solutions and charging facilities. Without cohesive co-evolving energy networks the planning and operational modelling of transport decarbonisation may fall short of meaningful real-world results. A developed understanding of the dependencies between the energy and transport systems is a necessary step in the development of meaningful operational transport models that could de-risk investment in both the energy and transport systems.
Green Electricity and Medical Electrolytic Oxygen from Solar Energy - A Sustainable Solution for Rural Hospitals.
Oct 2022
Publication
The objective of this paper is to design and simulate for rural areas isolated from the electricity grid a system based on solar energy for the optimal supply of green electricity and medical oxygen to a hospital. The system sized to produce 20 Nm3 /day is constituted of a 37.46 kW photovoltaic farm a 15.47 kW electrolyzer and a 15.47 kW fuel cell. The simulation of the Photovoltaic system is performed using the single diode model solved with the Lambert function defined in MATLAB Software. The daily production of oxygen and hydrogen during the sunniest day of the month is respectively 20.81 Nm3 /day and 41.61 Nm3 /day. The daily energy that can be stored is relevant to the hydrogen production and an electricity storage capacity of 124.89 kWh is feasible. During the least sunny day of the least sunny month the daily production of oxygen and hydrogen is respectively 7.72 Nm3 /day and 15.44 Nm3 /day. The recorded values prove that the system sized can constitute a viable solution to ensure the permanent supply a green electricity and oxygen to the hospital with good energy storage capacity.
A Comprehensive Review of Electrochemical Hybrid Power Supply Systems and Intelligent Energy Managements for Unmanned Aerial Vehicles in Public Services
Jun 2022
Publication
The electric unmanned aerial vehicles (UAVs) are rapidly growing due to their abilities to perform some difficult or dangerous tasks as well as many public services including real-time monitoring wireless coverage search and rescue wildlife surveys and precision agriculture. However the electrochemical power supply system of UAV is a critical issue in terms of its energy/power densities and lifetime for service endurance. In this paper the current power supply systems used in UAVs are comprehensively reviewed and analyzed on the existing power configurations and the energy management systems. It is identified that a single type of electrochemical power source is not enough to support a UAV to achieve a long-haul flight; hence a hybrid power system architecture is necessary. To make use of the advantages of each type of power source to increase the endurance and achieve good performance of the UAVs the hybrid systems containing two or three types of power sources (fuel cell battery solar cell and supercapacitor) have to be developed. In this regard the selection of an appropriate hybrid power structure with the optimized energy management system is critical for the efficient operation of a UAV. It is found that the data-driven models with artificial intelligence (AI) are promising in intelligent energy management. This paper can provide insights and guidelines for future research and development into the design and fabrication of the advanced UAV power systems.
A Review on CO2 Mitigation in the Iron and Steel Industry through Power to X Processes
Feb 2021
Publication
In this paper we present the first systematic review of Power to X processes applied to the iron and steel industry. These processes convert renewable electricity into valuable chemicals through an electrolysis stage that produces the final product or a necessary intermediate. We have classified them in five categories (Power to Iron Power to Hydrogen Power to Syngas Power to Methane and Power to Methanol) to compare the results of the different studies published so far gathering specific energy consumption electrolysis power capacity CO2 emissions and technology readiness level. We also present for the first time novel concepts that integrate oxy-fuel ironmaking and Power to Gas. Lastly we round the review off with a summary of the most important research projects on the topic including relevant data on the largest pilot facilities (2–6 MW).
Operation of Metal Hydride Hydrogen Storage Systems for Hydrogen Compression Using Solar Thermal Energy
Mar 2016
Publication
By using a newly constructed bench-scale hydrogen energy system with renewable energy ‘Pure Hydrogen Energy System’ the present study demonstrates the operations of a metal hydride (MH) tank for hydrogen compression as implemented through the use solar thermal energy. Solar thermal energy is used to generate hot water as a heat source of the MH tank. Thus 70 kg of LaNi5 one of the most typical alloys used for hydrogen storage was placed in the MH tank. We present low and high hydrogen flow rate operations. Then the operations under winter conditions are discussed along with numerical simulations conducted from the thermal point of view. Results show that a large amount of heat (>100 MJ) is generated and the MH hydrogen compression is available.
Effect of Wind on Cryogenic Hydrogen Dispersion from Vent Stacks
Sep 2021
Publication
Liquid hydrogen vent stacks often release hydrogen for example due to pressure relief from an underutilized tank boiling off hydrogen or after hydrogen delivery and transfer (trucks often depressurize through the tank vent stack to meet pressure regulations for on-road transport).<br/>A rapid release of cryogenic hydrogen through a vent stack will condense moisture from the entrained air forming a visible cloud. It is often assumed that the extent of the cold hydrogen is concurrent with the cloud. In this work a laser-based Raman scattering diagnostic was used to map out the hydrogen location during a series of vent stack release experiments. A description of the diagnostic instrument is given followed by a comparison of hydrogen signals to the visible cloud for releases through a liquid hydrogen vent stack. A liquid hydrogen pump was used to vary the flowrate of hydrogen through the vent stack and tests were performed under low and high wind conditions as well as low and high humidity conditions. The hydrogen was observed only where the condensed moisture was located regardless of the humidity level or wind. These measurements are being used to validate models such as those included in Sanda’s HyRAM toolkit and inform safety codes and standards.
Solar Energy: Applications, Trends Analysis, Bibliometric Analysis and Research Contribution to Sustainable Development Goals (SDGs)
Jan 2023
Publication
Over the past decade energy demand has witnessed a drastic increase mainly due to huge development in the industry sector and growing populations. This has led to the global utilization of renewable energy resources and technologies to meet this high demand as fossil fuels are bound to end and are causing harm to the environment. Solar PV (photovoltaic) systems are a renewable energy technology that allows the utilization of solar energy directly from the sun to meet electricity demands. Solar PV has the potential to create a reliable clean and stable energy systems for the future. This paper discusses the different types and generations of solar PV technologies available as well as several important applications of solar PV systems which are “Large-Scale Solar PV” “Residential Solar PV” “Green Hydrogen” “Water Desalination” and “Transportation”. This paper also provides research on the number of solar papers and their applications that relate to the Sustainable Development Goals (SDGs) in the years between 2011 and 2021. A total of 126513 papers were analyzed. The results show that 72% of these papers are within SDG 7: Affordable and Clean Energy. This shows that there is a lack of research in solar energy regarding the SDGs especially SDG 1: No Poverty SDG 4: Quality Education SDG 5: Gender Equality SDG 9: Industry Innovation and Infrastructure SDG 10: Reduced Inequality and SDG 16: Peace Justice and Strong Institutions. More research is needed in these fields to create a sustainable world with solar PV technologies.
Investigation of Hydrogen Leaks from Double Ferrule Fittings
Sep 2021
Publication
The use of hydrogen is expected to increase rapidly in the future. Leakage of hydrogen pipework are the main forms of safety problems in hydrogen utilization. In this paper a numerical model of hydrogen leakage and diffusion in pipe joints was established. The Schlieren + high-speed camera is used in experiments to observe the leakage of hydrogen in the pipe joints. In addition the shape and size of the scratches in the tube were statistically analyzed. Finally the leakage characteristics of double ferrule joints with scratches are experimentally analyzed. For the two scratch sizes the critical pressure values for the vortex transition are 0.2 MPa and 0.03 MPa. Through our experimental process some practical experience and suggestions are given.
A Promising Cobalt Catalyst for Hydrogen Production
Mar 2022
Publication
In this work a metal cobalt catalyst was synthesized and its activity in the hydrogen production process was tested. The substrates were water and ethanol. Activity tests were conducted at a temperature range of 350–600 °C water to ethanol molar ratio of 3 to 5 and a feed flow of 0.4 to 1.2 mol/h. The catalyst had a specific surface area of 1.75 m2/g. The catalyst was most active at temperatures in the range of 500–600 °C. Under the most favorable conditions the ethanol conversion was 97% the hydrogen production efficiency was 4.9 mol (H2)/mol(ethanol) and coke production was very low (16 mg/h). Apart from hydrogen and coke CO2 CH4 CO and traces of C2H2 and C2H4 were formed.
The Roles of Nuclear Energy in Hydrogen Production
Dec 2021
Publication
Fossil resources are unevenly distributed on the earth and are finite primary energy which is widely used in the fields of industry transportation and power generation etc.<br/>Primary energies that can replace fossil resources include renewable energy and nuclear energy. Hydrogen has the potential to be secondary energy that can be widely used in industry for various purposes. Nuclear energy can be used for producing hydrogen; it is becoming more important to convert this primary energies into hydrogen. This paper describes the roles of nuclear energy as a primary energy in hydrogen production from the viewpoint of the basics of energy form conversion.
Accurate Predictions of the Effect of Hydrogen Composition on the Thermodynamics and Transport Properties of Natural Gas
Mar 2024
Publication
This work demonstrates the need for accurate thermodynamic models to reliably quantify changes in the thermophysical properties of natural gas when blended with hydrogen. For this purpose a systematic evaluation was carried out on the predictive accuracy of three well-known models the Peng−Robinson equation of state (EoS) the multiparameter empirical GERG-2008 model and the molecular-based polar softSAFT EoS in describing the thermodynamic behavior of mixtures of hydrogen with commonly found components in natural gas. Deviations between the calculated properties and experimental data for phase equilibria critical loci second-order derivative properties and viscosities are used to determine the accuracy of the models with polar soft-SAFT performing either equally or better than the other two examined models. The evaluation for the effect of H2 content on the properties of methane simulated as natural gas at conditions for transportation reveals higher changes in blend density and speed of sound with increasing H2 content within 5% change per 5 mol % H2 added while viscosity is the least affected property changing by 0.4% for every 5 mol % H2.
Evidence Base Utilised to Justify a Hydrogen Blend Gas Network Safety Case
Sep 2021
Publication
Blending hydrogen with natural gas up to 20 % mol/mol has been identified as a key enabler of hydrogen deployment within the UK gas network. This work outlines the evidence base generated to form the basis of safety submitted to the Health and Safety Executive (HSE) to justify a demonstration of hydrogen blending on a live public gas network within the UK supplying a hydrogen blend to 668homes over the course of 10 months. An evidence base to demonstrate that gas users are not prejudiced by the addition of hydrogen is required by the Gas Safety (Management) Regulations [1] to allow hydrogen distribution above the 0.1 mol% limit specified within the regulations. The technical evidence generated to support the safety case presented to the HSE concerned the implications of introducing a hydrogen blend on appliance operation materials gas characteristics and operational procedures. The outputs of the technical evidence workstreams provided input data to a Quantitative Risk Assessment (QRA) of the GB gas distribution network. The QRA was developed in support of the safety case to allow a causal understanding of public risk to be understood where harm due to gas usage was defined as risk to life caused either by carbon monoxide poisoning or as a result of fires/explosions. Public records were used to calibrate and validate the base risk model to understand the dynamics of public risk due to natural gas usage. The experimental and analytical results of the technical workstreams were then used to derive risk model inputs relating to a hydrogen blend. This allowed a quantified comparison of risk to be understood to demonstrate parity of safety between natural gas and a hydrogen blend. This demonstration of risk parity is a condition precedent of allowing the distribution and utilisation of hydrogen blends within the GB gas network.
Everything About Hydrogen Podcast: Storage for the Future!
Jan 2022
Publication
For our first episode of 2022 we invited Jørn Helge Dahl Global Director of Sales&Marketing at Hexagon Purus to talk about hydrogen storage with the EAH podcast and to explain the types of solutions available today Hexagon's history and plans for the future alongside some commentary on US hydrogen strategy from the gang.
The podcast can be found on their website
The podcast can be found on their website
Research Efforts for the Resolution of Hydrogen Risk
Jan 2015
Publication
During the past 10 years the Korea Atomic Energy Research Institute (KAERI) has performed a study to control hydrogen gas in the containment of the nuclear power plants. Before the Fukushima accident analytical activities for gas distribution analysis in experiments and plants were primarily conducted using a multidimensional code: the GASFLOW. After the Fukushima accident the COM3D code which can simulate a multi-dimensional hydrogen explosion was introduced in 2013 to complete the multidimensional hydrogen analysis system. The code validation efforts of the multidimensional codes of the GASFLOW and the COM3D have continued to increase confidence in the use of codes using several international experimental data. The OpenFOAM has been preliminarily evaluated for APR1400 containment based on experience from coded validation and the analysis of hydrogen distribution and explosion using the multidimensional codes the GASFLOW and the COM3D. Hydrogen safety in nuclear power has become a much more important issue after the Fukushima event in which hydrogen explosions occurred. The KAERI is preparing a large-scale test that can be used to validate the performance of domestic passive autocatalytic recombiners (PARs) and can provide data for the validation of the severe accident code being developed in Korea
Golden Hydrogen
Nov 2022
Publication
Hydrogen is a colorless compound to which symbolic colors are attributed to classify it according to the resources used in production production processes such as electrolysis and energy vectors such as solar radiation. Green hydrogen is produced mainly by electrolysis of water using renewable electricity from an electricity grid powered by wind geothermal solar or hydroelectric power plants. For grid-powered electrolyzers the tendency is to go larger to reach the gigawatt-scale. An evolution in the opposite direction is the integration of the photophysics of sunlight harvesting and the electrochemistry of water molecule splitting in solar hydrogen generator units with each unit working at kilowatt-scale or less. Solar hydrogen generators are intrinsically modular needing multiplication of units to reach gigawatt-scale. To differentiate these two fundamentally different technologies the term ‘golden hydrogen’ is proposed referring to hydrogen produced by modular solar hydrogen generators. Decentralized modular production of golden hydrogen is complementary to centralized energy-intensive green hydrogen production. The differentiation between green hydrogen and golden hydrogen will facilitate the introduction of the additionality principle in clean hydrogen policy.
Gas Turbine Enclosures: Determining Ventilation Safety Criteria using Hydrogen Explosion Modelling
Sep 2021
Publication
Dilution ventilation is the current basis of safety following a flammable gas leak within a gas turbine enclosure and compliance requirements are defined for methane fuels in ISO 21789. These requirements currently define a safety criteria of a maximum flammable gas cloud size within an enclosure. The requirements are based on methane explosion tests conducted during a HSE Joint Industry Project which identified typical pressures associated with a range of gas cloud sizes. The industry standard approach is to assess the ventilation performance of specific enclosure designs against these requirements using CFD modelling. Gas turbine manufacturers are increasingly considering introducing hydrogen/methane fuel mixtures and looking towards operating with hydrogen alone. It is therefore important to review the applicability of current safety standards for these new fuels as the pressure resulting from a hydrogen explosion is expected to be significantly higher than that from a methane explosion. In this paper we replicate the previous methane explosion tests for hydrogen and hydrogen/methane fuel mixtures using the explosion modelling tool FLACS CFD. The results are used to propose updated limiting safety criteria for hydrogen fuels to support ventilation CFD analysis for specific enclosure designs. It is found that significantly smaller gas cloud sizes are likely to be acceptable for gas turbines fueled by hydrogen however significantly more hydrogen than methane is required per unit volume to generate a stoichiometric cloud (as hydrogen has a lower stoichiometric air fuel ratio than methane). This effect results in the total quantity of gas in the enclosure (and as such detectability of the gas) being broadly similar when operating gas turbines on hydrogen when compared to methane.
Optimization of Component Sizing for a Fuel Cell-Powered Truck to Minimize Ownership Cost
Mar 2019
Publication
In this study we consider fuel cell-powered electric trucks (FCETs) as an alternative to conventional medium- and heavy-duty vehicles. FCETs use a battery combined with onboard hydrogen storage for energy storage. The additional battery provides regenerative braking and better fuel economy but it will also increase the initial cost of the vehicle. Heavier reliance on stored hydrogen might be cheaper initially but operational costs will be higher because hydrogen is more expensive than electricity. Achieving the right tradeoff between these power and energy choices is necessary to reduce the ownership cost of the vehicle. This paper develops an optimum component sizing algorithm for FCETs. The truck vehicle model was developed in Autonomie a platform for modelling vehicle energy consumption and performance. The algorithm optimizes component sizes to minimize overall ownership cost while ensuring that the FCET matches or exceeds the performance and cargo capacity of a conventional vehicle. Class 4 delivery truck and class 8 linehaul trucks are shown as examples. We estimate the ownership cost for various hydrogen costs powertrain components ownership periods and annual vehicle miles travelled.
Hydrogen Generation in Europe: Overview of Costs and Key Benefits
May 2021
Publication
The European Commission published its hydrogen strategy for a climate-neutral Europe on the 8th July 2020. This strategy brings different strands of policy action together covering the entire value chain as well as the industrial market and infrastructure angles together with the research and innovation perspective and the international dimension in order to create an enabling environment to scale up hydrogen supply and demand for a climate-neutral economy. The strategy also highlights clean hydrogen and its value chain as one of the essential areas to unlock investment to foster sustainable growth and jobs which will be critical in the context of recovery from the COVID-19 crisis. It sets strategic objectives to install at least 6 GW of renewable hydrogen electrolysers by 2024 and at least 40 GW of renewable hydrogen electrolysers by 2030 and foresees industrial applications and mobility as the two main lead markets. This report provides the evidence base established on the latest publicly available data for identifying investment opportunities in the hydrogen value chain over the period from 2020 to 2050 and the associated benefits in terms of jobs. Considering the dynamics and significant scale-up expected over a very short period of time multiple sources have been used to estimate the different values consistently and transparently. The report covers the full value chain from the production of renewable electricity as the energy source for renewable hydrogen production to the investment needs in industrial applications and hydrogen trucks and buses. Although the values range significantly across the different sources the overall trend is clear. Driving hydrogen development past the tipping point needs critical mass in investment an enabling regulatory framework new lead markets sustained research and innovation into breakthrough technologies and for bringing new solutions to the market a large-scale infrastructure network that only the EU and the single market can offer and cooperation with our third country partners. All actors public and private at European national and regional level must work together across the entire value chain to build a dynamic hydrogen ecosystem in Europe.
A General Vision for Reduction of Energy Consumption and CO2 Emissions from the Steel Industry
Aug 2020
Publication
The 2018 IPCC (The Intergovernmental Panel on Climate Change’s) report defined the goal to limit global warming to 1.5 ◦C by 2050. This will require “rapid and far-reaching transitions in land energy industry buildings transport and cities”. The challenge falls on all sectors especially energy production and industry. In this regard the recent progress and future challenges of greenhouse gas emissions and energy supply are first briefly introduced. Then the current situation of the steel industry is presented. Steel production is predicted to grow by 25–30% by 2050. The dominant iron-making route blast furnace (BF) especially is an energy-intensive process based on fossil fuel consumption; the steel sector is thus responsible for about 7% of all anthropogenic CO2 emissions. In order to take up the 2050 challenge emissions should see significant cuts. Correspondingly specific emissions (t CO2/t steel) should be radically decreased. Several large research programs in big steelmaking countries and the EU have been carried out over the last 10–15 years or are ongoing. All plausible measures to decrease CO2 emissions were explored here based on the published literature. The essential results are discussed and concluded. The specific emissions of “world steel” are currently at 1.8 t CO2/t steel. Improved energy efficiency by modernizing plants and adopting best available technologies in all process stages could decrease the emissions by 15–20%. Further reductions towards 1.0 t CO2/t steel level are achievable via novel technologies like top gas recycling in BF oxygen BF and maximal replacement of coke by biomass. These processes are however waiting for substantive industrialization. Generally substituting hydrogen for carbon in reductants and fuels like natural gas and coke gas can decrease CO2 emissions remarkably. The same holds for direct reduction processes (DR) which have spread recently exceeding 100 Mt annual capacity. More radical cut is possible via CO2 capture and storage (CCS). The technology is well-known in the oil industry; and potential applications in other sectors including the steel industry are being explored. While this might be a real solution in propitious circumstances it is hardly universally applicable in the long run. More auspicious is the concept that aims at utilizing captured carbon in the production of chemicals food or fuels e.g. methanol (CCU CCUS). The basic idea is smart but in the early phase of its application the high energy-consumption and costs are disincentives. The potential of hydrogen as a fuel and reductant is well-known but it has a supporting role in iron metallurgy. In the current fight against climate warming H2 has come into the “limelight” as a reductant fuel and energy storage. The hydrogen economy concept contains both production storage distribution and uses. In ironmaking several research programs have been launched for hydrogen production and reduction of iron oxides. Another global trend is the transfer from fossil fuel to electricity. “Green” electricity generation and hydrogen will be firmly linked together. The electrification of steel production is emphasized upon in this paper as the recycled scrap is estimated to grow from the 30% level to 50% by 2050. Finally in this review all means to reduce specific CO2 emissions have been summarized. By thorough modernization of production facilities and energy systems and by adopting new pioneering methods “world steel” could reach the level of 0.4–0.5 t CO2/t steel and thus reduce two-thirds of current annual emissions.
The Impact of Fuel Cell Electric Freight Vehicles on Fuel Consumption and CO2 Emissions: The Case of Italy
Oct 2022
Publication
The Italian Recovery and Resilience Plan promotes among its many actions the use of hydrogen by the deployment of refuelling stations for heavy-duty vehicles predicting a 5–7% penetration rate of fuel cell electric vehicles (FCEVs) for long-distance freight transport. In this work the impact of this action on the reduction of greenhouse gas emissions and consumption was estimated assuming the plan’s objectives are met. To achieve this aim a national simulation model of the road freight transport system was implemented consisting of a graph of the national road network and an inter-provincial origin-destination matrix; the graph was based on data available from OpenStreetMap while the interprovincial matrix was estimated from the interregional matrix with the use of two linear regression models one for emitted goods and one for attracted goods. The simulation of the system made it possible to estimate the impact of this action on CO2 emissions and fuel consumption under three different scenarios. From 2025 to 2040 a reduction in CO2 emissions ranging from around 9 to around 16.5 million tonnes was estimated and a reduction in consumption ranging from around 3 billion to around 5.6 billion litres of diesel. These results show how this action can be seen as one of the bricks contributing to the fight against global warming.
Numerical Simulations of Suppression Effect of Water Mist on Hydrogen Deflagration in Confined Spaces
Sep 2021
Publication
Hydrogen safety issues attract focuses increasingly as more and more hydrogen powered vehicles are going to be operated in traffic infrastructures of different kinds like tunnels. Due to the confinement feature of traffic tunnels hydrogen deflagration may pose a risk when a hydrogen leak event occurs in a tunnel e.g. failure of the hydrogen storage system caused by a car accident in a tunnel. A water injection system can be designed in tunnels as a mitigation measure to suppress the pressure and thermal loads of hydrogen combustion in accident scenarios. The COM3D is a fully verified three-dimensional finite-difference turbulent flow combustion code which models gas mixing hydrogen combustion and detonation in nuclear containment with mitigation device or other confined facilities like vacuum vessel of fusion and semi-confined hydrogen facilities in industry such as traffic tunnels hydrogen refueling station etc. Therefore by supporting of the European HyTunnel-CS project the COM3D is applied to simulate numerically the hydrogen deflagration accident in a tunnel model being suppressed by water mist injection. The suppression effect of water mist and the suppression mechanism is elaborated and discussed in the study.
Petroleum Sector-Driven Roadmap for Future Hydrogen Economy
Nov 2021
Publication
In the climate change mitigation context based on the blue hydrogen concept a narrative frame is presented in this paper to build the argument for solving the energy trilemma which is the possibility of job loss and stranded asset accumulation with a sustainable energy solution in gas- and oil-rich regions especially for the Persian Gulf region. To this aim scientific evidence and multidimensional feasibility analysis have been employed for making the narrative around hydrogen clear in public and policy discourse so that choices towards acceleration of efforts can begin for paving the way for the future hydrogen economy and society. This can come from natural gas and petroleum-related skills technologies experience and infrastructure. In this way we present results using multidimensional feasibility analysis through STEEP and give examples of oil- and gas-producing countries to lead the transition action along the line of hydrogen-based economy in order to make quick moves towards cost effectiveness and sustainability through international cooperation. Lastly this article presents a viewpoint for some regional geopolitical cooperation building but needs a more full-scale assessment.
Hydrogen Embrittlement in a 2101 Lean Duplex Stainless Steel
Sep 2019
Publication
Duplex Stainless Steels (DSSs) are an attractive class of materials characterized by a strong corrosion resistance in many aggressive environments. Thanks to the high mechanical performances DSSs are widely used for many applications in petrochemical industry chemical and nuclear plants marine environment desalination etc.<br/>Among the DSSs critical aspects concerning the embrittlement process it is possible to remember the steel sensitization and the hydrogen embrittlement.<br/>The sensitization of the DSSs is due to the peculiar chemical composition of these grades which at high temperature are susceptible to carbide nitrides and second phases precipitation processes mainly at grains boundary and in the ferritic grains. The hydrogen embrittlement process is strongly influenced by the duplex (austenitic-ferritic) microstructure and by the loading conditions.<br/>In this work a rolled lean ferritic-austenitic DSS (2101) has been investigated in order to analyze the hydrogen embrittlement mechanisms by means of slow strain rate tensile tests considering the steel after different heat treatments. The damaging micromechanisms have been investigated by means of the scanning electron microscope observations on the fracture surfaces.
Steel Manufacturing Clusters in a Hydrogen Economy – Simulation of Changes in Location and Vertical Integration of Steel Production in Northwestern Europe
Feb 2022
Publication
With the move to a hydrogen-based primary steel production envisioned for the near future in Europe existing regional industrial clusters loose major assets. Such a restructuring of industries may result in a new geographical distribution of the steel industry and also to another quality of vertical integration at sites. Both implications could turn out as drivers or barriers to invest in new technologies and are thus important in respect to vertical integration of sites and to regional policy. This paper describes an approach to model production stock invest for the steel industries in North-Western Europe. Current spatial structures are reproduced with capacity technical and energy efficiency data on the level of single facilities like blast furnaces. With the model developed both investments in specific technologies and at specific production sites can be modelled. The model is used to simulate different possible future scenarios. The case with a clear move to hydrogen-based production is compared to a reference scenario without technological shift. The scenarios show that existing trends like movement of production to the coast may be accelerated by the new technology but that sites in the hinterland can also adapt to a hydrogen economy. Possible effects of business cycles or a circular economy on regional value chains are explored with a Monte-Carlo analysis.
Effect of Defects and Hydrogen on the Fatigue Limit of Ni-based Superalloy 718
Dec 2019
Publication
Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular the fatigue strength susceptibility to defects varied significantly according to the type of microstructural morphology i.e. a smaller grain size made the alloy more vulnerable to defects. The fatigue limit as a small-crack threshold was successfully predicted using the √area parameter model. Depending on the size of defects the fatigue limit was calculated in relation to three phases: (i) harmless-defect regime (ii) small-crack regime and (iii) large-crack regime. Such a classification enabled comprehensive fatigue limit evaluation in a wide array of defects taking into consideration (a) the defect size over a range of small crack and large crack and (b) the characteristics of the matrix represented by grain size and hardness. In addition the effect of defects and hydrogen on fatigue strength will be comprehensively discussed based on a series of experimental results.
Economic Optima for Buffers in Direct Reduction Steelmaking Under Increasing Shares of Renewable Hydrogen
Oct 2021
Publication
While current climate targets demand substantial reductions in greenhouse gas (GHG) emissions the potentials to further reduce carbon dioxide emissions in traditional primary steel-making are limited. One possible solution that is receiving increasing attention is the direct reduction (DR) technology operated either with renewable hydrogen (H2) from electrolysis or with conventional natural gas (NG). DR technology makes it possible to decouple steel and hydrogen production by temporarily using overcapacities to produce and store intermediary products during periods of low renewable electricity prices or by switching between H2 and NG. This paper aims to explore the impact of this decoupling on overall costs and the corresponding dimensioning of production and storage capacities. An optimization model is developed to determine the least-cost operation based on perfect-foresight. This model can determine the minimum costs for optimal production and storage capacities under various assumptions considering fluctuating H2 and NG prices and increasing H2 shares. The model is applied to a case study for Germany and covers the current situation the medium term until 2030 and the long term until 2050. Under the assumptions made the role of using direct reduced iron (DRI) storage as a buffer seems less relevant. DRI mainly serves as long-term storage for several weeks similar to usual balancing storage capacities. Storing H2 on the contrary is used for short-term fluctuations and could balance H2 demand in the hourly range until 2050. From an economic perspective DRI production using NG tends to be cheaper than using H2 in the short term and potential savings from the flexible operation with storages are small at first. However in the long term until 2050 NG and H2 could achieve similar total costs if buffers are used. Otherwise temporarily occurring electricity price spikes imply substantial increases in total costs if high shares of H2 need to be achieved.
Everything About Hydrogen Podcast: Costs, Cost, Costs!
Aug 2020
Publication
On this week's episode of Everything About Hydrogen the team are celebrating the show's one year anniversary with Randy MacEwen the CEO of Ballard Power Systems. On the show the team ask Randy to explain the stunning rise of hydrogen over the last 12-24 months how the use cases for hydrogen are evolving and how the growing capitalisation of listed businesses like Ballard is driving a change in the investor base across the hydrogen & fuel cell sector. We also dive into the future for Ballard where the challenges and focuses for the business lie while the team reflect on what has been a very intense year for the show and the hydrogen industry. All this and more!
The podcast can be found on their website
The podcast can be found on their website
Integration of Hydrogen and Synthetic Natural Gas within Legacy Power Generation Facilities
Jun 2022
Publication
Whilst various new technologies for power generation are continuously being evaluated the owners of almost-new facilities such as combined-cycle gas turbine (CCGT) plants remain motivated to adapt these to new circumstances and avoid the balance-sheet financial impairments of underutilization. Not only are the owners reluctant to decommission the legacy CCGT assets but system operators value the inertia and flexibilities they contribute to a system becoming predominated with renewable generation. This analysis therefore focuses on the reinvestment cases for adapting CCGT to hydrogen (H2 ) synthetic natural gas (SNG) and/or retrofitted carbon capture and utilization systems (CCUS). Although H2 either by itself or as part of SNG has been evaluated attractively for longer-term electricity storage the business case for how it can be part of a hybrid legacy CCGT system has not been analyzed in a market context. This work compares the power to synthetic natural gas to power (PSNGP) adaptation with the simpler and less expensive power to hydrogen to power (P2HP) adaptation. Both the P2HP and PSNGP configurations are effective in terms of decarbonizations. The best results of the feasibility analysis for a UK application with low CCGT load factors (around 31%) were obtained for 100% H2 (P2HP) in the lower range of wholesale electricity prices (less than 178 GBP/MWh) but in the higher range of prices it would be preferable to use the PSNGP configuration with a low proportion of SNG (25%). If the CCGT load factor increased to 55% (the medium scenario) the breakeven profitability point between P2HP and PSNGP decreased to a market price of 145 GBP/MWh. Alternatively with the higher load factors (above 77%) satisfactory results were obtained for PSNGP using 50% SNG if with market prices above 185 GBP/MWh.
Cradle-grave Energy Consumption, Greenhouse Gas and Acidification Emissions in Current and Future Fuel Cell Vehicles: Study Based on Five Hydrogen Production Methods in China
Jun 2022
Publication
Hydrogen fuel cell vehicles (FCVs) are regarded as a promising solution to the problems of energy security and environmental pollution. However the technology is under development and the hydrogen consumption is uncertain. The quantitative evaluation of life cycle energy consumption pollution emissions of current and future FCVs in China involves complex processes and parameters. Therefore this study addresses Life Cycle Assessment (LCA) of FCV and focuses on the key parameters of FCV production and different hydrogen production methods which include steam methane reforming catalysis decomposition methanol steam reforming electrolysis–photovoltaic (PV) and electrolysis Chinese electricity grid mix (CN). Sensitivity analysis of bipolar plate glider mass power density fuel cell system efficiency and energy control strategy are performed whilst accounting for different assumption scenarios. The results show that all impact assessment indicators will decrease by 28.8– 44.3% under the 2030 positive scenario for the production of FCVs. For cradle-grave FCVs the use of hydrogen from electrolysis operated with photovoltaic power reduces global warming potential (GWP) by almost 76.4% relative to steam methane reforming. By contrast the use of hydrogen from electrolysis operated with the Chinese electricity grid mix results in an increase in GWP of almost 158.3%.
Investigation on Cooling Effect of Water Sprays on Tunnel Fires of Hydrogen
Sep 2021
Publication
As one of the most promising renewable green energies hydrogen power is a popularly accepted option to drive automobiles. Commercial application of fuel cell vehicles has been started since 2015. More and more hydrogen safety concerns have been considered for years. Tunnels are an important part of traffic infrastructure with a mostly confined feature. Hydrogen leak followed possibly by a hydrogen fire is a potential accident scenario which can be triggered trivially by a car accident while hydrogen powered vehicles operate in a tunnel. Water spray is recommended traditionally as a mitigation measure against tunnel fires. The interaction between water spray and hydrogen fire is studied in a way of numerical simulations. By using the computer program of Fire Dynamics Simulator (FDS) tunnel fires of released hydrogen in different scales are simulated coupled with water droplet injections featured in different droplet sizes or varying mass flow rates. The cooling effect of spray on hot gases of hydrogen fires is apparently observed in the simulations. However in some circumstance the turbulence intensified by the water injection can prompt hydrogen combustion which is a negative side-effect of the spray.
Experimental Study on Tri-fuel Combustion Using Premixed Methane-hydrogen Mixtures Ignited by a Diesel Pilot
Apr 2021
Publication
A comprehensive investigation on diesel pilot spray ignited methane-hydrogen (CH4–H2) combustion tri-fuel combustion (TF) is performed in a single-cylinder compression ignition (CI) engine. The experiments provide a detailed analysis of the effect of H2 concentration (based on mole fraction MH2) and charge-air temperature (Tair) on the ignition behavior combustion stability cycle-to-cycle (CCV) and engine performance. The results indicate that adding H2 from 0 to 60% shortens the ignition delay time (IDT) and combustion duration (based on CA90) up to 33% and 45% respectively. Thereby H2 helps to increase the indicated thermal efficiency (ITE) by as much as 10%. Furthermore to gain an insight into the combustion stability and CCV the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) methodologies are applied to estimate the combustion stability and CCV of the TF combustion process. The results reveal that the pressure oscillation can be reduced up to 4 dB/Hz and the CCV by 50% when MH2 < 60% and Tair < 55 °C. However when MH2 > 60% and Tair > 40 °C abnormal combustion and knocking are observed.
Development of Risk Mitigation Guidance for Sensor Placement Inside Mechanically Ventilated Enclosures – Phase 1
Sep 2019
Publication
Guidance on Sensor Placement was identified as the top research priority for hydrogen sensors at the 2018 HySafe Research Priority Workshop on hydrogen safety in the category Mitigation Sensors Hazard Prevention and Risk Reduction. This paper discusses the initial steps (Phase 1) to develop such guidance for mechanically ventilated enclosures. This work was initiated as an international collaborative effort to respond to emerging market needs related to the design and deployment equipment for hydrogen infrastructure that is often installed in individual equipment cabinets or ventilated enclosures. The ultimate objective of this effort is to develop guidance for an optimal sensor placement such that when integrated into a facility design and operation will allow earlier detection at lower levels of incipient leaks leading to significant hazard reduction. Reliable and consistent early warning of hydrogen leaks will allow for the risk mitigation by reducing or even eliminating the probability of escalation of small leaks into large and uncontrolled events. To address this issue a study of a real-world mechanically ventilated enclosure containing GH2 equipment was conducted where CFD modelling of the hydrogen dispersion (performed by AVT and UQTR and independently by the JRC) was validated by the NREL Sensor laboratory using a Hydrogen Wide Area Monitor (HyWAM) consisting of a 10-point gas and temperature measurement analyzer. In the release test helium was used as a hydrogen surrogate. Expansion of indoor releases to other larger facilities (including parking structures vehicle maintenance facilities and potentially tunnels) and incorporation into QRA tools such as HyRAM is planned for Phase 2. It is anticipated that results of this work will be used to inform national and international standards such as NFPA 2 Hydrogen Technologies Code Canadian Hydrogen Installation Code (CHIC) and relevant ISO/TC 197 and CEN documents.
Towards the Efficient and Time-accurate Simulations of Early Stages of Industrial Explosions
Sep 2021
Publication
Combustion during a nuclear reactor accident can result in pressure loads that are potentially fatal for the structural integrity of the reactor containment or its safety equipment. Enabling efficient modelling of such safety-critical scenarios is the goal of ongoing work. In this paper attention is given to capturing early phases of flame propagation. Transient simulations that are not prohibitively expensive for use at industrial scale are required given that a typical flame propagation study takes a large number of simulation time steps to complete. An improved numerical method used in this work is based on explicit time integration by means of Strong Stability Preserving (SSP) Runge-Kutta schemes. These allow an increased time step size for a given level of accuracy—reducing the overall computational effort. Furthermore a wide range of flow conditions is encountered in analysis of accelerating flames: from incompressible to potentially supersonic. In contrast numerical schemes for spatial discretization would often prove lacking in either stability or accuracy outside the intended flow regime—with density-based schemes being traditionally designed and applied to compressible (Ma>0.3) flows. In the present work a formulation of an all-speed density-based numerical flux scheme is used for simulation of slow flames starting from ignition. Validation was carried out using experiments with spherical lean hydrogen flames at laboratory scale. Turbulence conditions in the experiments correspond to those that can arise in a nuclear reactor containment during an accident. Results show that the new numerical method has the potential to predict flame speed and pressure rise at a reduced computational effort.
Non-Precious Electrodes for Practical Alkaline Water Electrolysis
Apr 2019
Publication
Water electrolysis is a promising approach to hydrogen production from renewable energy sources. Alkaline water electrolyzers allow using non-noble and low-cost materials. An analysis of common assumptions and experimental conditions (low concentrations low temperature low current densities and short-term experiments) found in the literature is reported. The steps to estimate the reaction overpotentials for hydrogen and oxygen reactions are reported and discussed. The results of some of the most investigated electrocatalysts namely from the iron group elements (iron nickel and cobalt) and chromium are reported. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The experimental work is done involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at temperatures between 30 and 100 ◦C which are closer to industrial applications than what is usually found in literature. Stable cell components and a good performance was achieved using Raney nickel as a cathode and stainless steel 316L as an anode by means of a monopolar cell at 75 ◦C which ran for one month at 300 mA cm−2 . Finally the proposed catalysts showed a total kinetic overpotential of about 550 mV at 75 ◦C and 1 A cm−2.
Operation Potential Evaluation of Multiple Hydrogen Production and Refueling Integrated Stations Under DC Interconnected Environment
Feb 2022
Publication
Hydrogen production and refueling integrated station can play an important role in the development of hydrogen transportation and fuel cell vehicles and actively promote the energy transformation. By using DC system for hydrogen production and refueling the conversion links can be reduced and the system efficiency can be effectively improved. In this paper a new scheme of DC interconnection for hydrogen production and refueling integrated station is proposed and the modular modeling and operation capability evaluation method are proposed including the characteristic analysis of integrated station the modular modeling and evaluation method for multiple integrated stations under DC interconnection. The DC interconnection system of five integrated stations is constructed and operation capability improvement of integrated stations after adopting the innovative DC interconnection scheme is analyzed. On this basis the system simulation model based on MATLAB/Simulink and physical test platform are built to verify the effectiveness of the theoretical analysis.
Effect of Flow Speed on Ignition Characteristics of Hydrogen/air Mixtures
Sep 2021
Publication
A fuel cell vehicle has a purging system for exhausting contaminated hydrogen gas. Notwithstanding the allowable hydrogen emissions levels in the purging system are regulated by the GTR a further research on the safety requirement of emissions concentrations is therefore needed for the vehicle design into a more rational system. In the present study the effects of flow speed concentration humidity on ignition characteristics of hydrogen/air mixtures were experimentally investigated. The results demonstrate that the value of Lower Flammable Limit increased with an increase in the velocity of hydrogen/air mixtures and slightly increased with a decrease in oxygen concentration.
Exploring the Australian Public's Response to Hydrogen
Sep 2021
Publication
Over the past three years there has been a rapid increase in discussions across the different levels of Australia's governments about the role that hydrogen might play in helping the world transition to a low carbon future. While those working in the energy industry are aware of the opportunities and challenges that lay ahead the general public is less engaged. However we know from the introduction of previous technologies that public attitudes towards technologies including whether they view them to be safe can severely impact overall acceptance. Understanding how the public perceives hydrogen both for domestic and export use and the potential benefits it brings to Australia is critical for the industry to progress. In this paper we present the initial findings of a national survey of the Australian public conducted in March 2021 which builds on the results of a previous survey conducted in 2018. The 2021 respondents were drawn from all Australian states and territories (n=3020) and quotas were used to ensure adequate representation of age groups and gender. Overall the respondents have favorable views about using hydrogen for energy in Australia with caveats about production-related environmental impacts and issues such as safety. While there has been a slight increase in support for hydrogen as a possible solution for energy and environmental challenges since the 2018 survey the effect size is very small. This suggests that while hydrogen discussions have increased at a policy level little has been done to improve public understanding of hydrogen in communication strategies will be needed as the Australian hydrogen industry continues to develop and gain more widespread media attention.
Stronger Together: Multi-annual Variability of Hydrogen Production Supported by Wind Power in Sweden
Mar 2021
Publication
Hydrogen produced from renewable electricity will play an important role in deep decarbonisation of industry. However adding large electrolyser capacities to a low-carbon electricity system also increases the need for additional electricity generation from variable renewable energies. This will require hydrogen production to be variable unless other sources provide sufficient flexibility. Existing sources of flexibility in hydro-thermal systems are hydropower and thermal generation which are both associated with sustainability concerns. In this work we use a dispatch model for the case of Sweden to assess the power system operation with large-scale electrolysers assuming that additional wind power generation matches the electricity demand of hydrogen production on average. We evaluate different scenarios for restricting the flexibility of hydropower and thermal generation and include 29 different weather years to test the impact of variable weather regimes. We show that (a) in all scenarios electrolyser utilisation is above 60% on average (b) the inter-annual variability of hydrogen production is substantial if thermal power is not dispatched for electrolysis and (c) this problem is aggravated if hydropower flexibility is also restricted. Therefore either long-term storage of hydrogen or backup hydrogen sources may be necessary to guarantee continuous hydrogen flows. Large-scale dispatch of electrolysis capacity supported by wind power makes the system more stable if electrolysers ramp down in rare hours of extreme events with low renewable generation. The need for additional backup capacities in a fully renewable electricity system will thus be reduced if wind power and electrolyser operation are combined in the system.
Quantitive Risk Assessment of the Model Representing Latest Japanese Hydrogen Refuelling Stations
Sep 2021
Publication
Current safety codes and technical standards related to Japanese hydrogen refueling stations (HRSs) have been established based on qualitative risk assessment and quantitative effectiveness validation of safety measures for more than ten years. In the last decade there has been significant development in the technologies and significant increment in operational experience related to HRSs. We performed a quantitative risk assessment (QRA) of the HRS model representing Japanese HRSs with the latest information in the previous study. The QRA results were obtained by summing risk contours derived from each process unit. They showed that the risk contours of 10-3 and 10-4 per year were confined within the HRS boundaries whereas those of 10-5 and 10-6 per year are still present outside the HRS boundaries. Therefore we analyzed the summation of risk contours derived from each unit and identified the largest risk scenarios outside the station. The HRS model in the previous study did not consider fire and blast protection walls which could reduce the risks outside the station. Therefore we conducted a detailed risk analysis of the identified scenarios using 3D structure modeling. The heat radiation and temperature rise of jet fire scenarios that pose the greatest risk to the physical surroundings in the HRS model were estimated in detail based on computational fluid dynamics with 3D structures including fire protection walls. Results show that the risks spreading outside the north- west- and east-side station boundaries are expected to be acceptable by incorporating the fire protection wall into the Japanese HRS model.
Everything About Hydrogen Podcast: Where Does Hydrogen Fit in the Global Energy Transition?
Apr 2022
Publication
On this episode the EAH team discusses the role of hydrogen in the energy transition with Michael Liebreich Chairman and CEO of Liebreich Associates. Michael is an acknowledged thought leader on clean energy mobility technology climate sustainability and finance. He is the founder and senior contributor to Bloomberg New Energy Finance a member of numerous industry governmental and multilateral advisory boards an angel investor a former member of the board of Transport for London and an Advisor to the UK Board of Trade.
The podcast can be found on their website
The podcast can be found on their website
An Experimental Study of Propagating Spherical Flames in Unconfined Hydrogen-oxygen Explosions
Sep 2021
Publication
The study to understand the flame propagation behaviors of hydrogen-oxygen explosions is required to make a precise risk assessment. Moreover although research has investigated the propagating spherical flames in unconfined hydrogen-air explosions no study to date has examined the hydrogen-oxygen explosions. The spherical flame propagation in unconfined hydrogen-oxygen explosions have been investigated using a soap bubble method. In the present experiments hydrogen-oxygen mixtures were filled in a 10 cm diameter soap bubble and ignited by an electric spark at the center. The flame propagation behaviors were measured by a high-speed Schlieren photography. The laminar burning velocities and critical flame radii for the onset of flame acceleration in unconfined hydrogen-oxygen explosions were estimated. Results demonstrated that the laminar burning velocities of hydrogenoxygen mixtures were much faster than those of hydrogen-air mixtures. In addition the shift value of maximum laminar burning velocity for hydrogen-oxygen mixtures towards a leaner equivalence ratio is observed. The experimental flame speeds for all experiments were increased owing to diffusionalthermal and Darrieus-Landau instabilities although the measured flame radii were small. The critical flame radius corresponding to the onset of flame acceleration decreased with the decrease in equivalence ratio.
Numerical Study of Hydrogen Addition Effects on Aluminum Particle Combustion
Sep 2021
Publication
In this study the combustion of submicron-sized Al particles in air was studied numerically with a particular focus on the effect of hydrogen addition. Oxidation of the Al particles and the interaction with hydrogen-related intermediates were considered by regarding them as liquid-phase molecules initially. Zero- and One-dimensional numerical simulations were then carried out to investigate the effect of the hydrogen addition on fundamental combustion characteristics of the Al flame by calculating properties such as ignition delay time and flame speed. Our attention was paid to how the hydrogen chemistry is coupled with the Al oxidation process. Numerical results show that the hydrogen addition generally reduces the reactivity of Al such that the flame speed and temperature decrease while it can greatly shorten ignition delay times of the Al flame depending on initial temperatures.
Safety Planning and Management in EU Hydrogen and Fuel Cells Projects - Guidance Document
Sep 2021
Publication
The document provides information on safety planning implementation and reporting for projects involving hydrogen and/or fuel cell technologies. It does not intend to replace or contradict existing regulations which prevail under all circumstances. Neither is it meant to conflict with relevant international or national standards or to replace existing company safety policies codes and procedures. Instead this guidance document aims to assist projects and project partners in identifying hazards and associated risks in prevention and/or mitigation of them through a proper safety plan in implementing the safety plan and reporting safety related events. This shall help in safely delivering the project and ultimately producing inherently safer systems processes and infrastructure.
Sustainable Synthetic Carbon Based Fuels for Transport
Sep 2019
Publication
The report considers two types of sustainable synthetic fuels: electro fuels (efuels) and synthetic biofuels. Efuels are made by combining hydrogen (from for example the electrolysis of water) with carbon dioxide (from direct air capture or a point source). Synthetic biofuels can be made from biological material (for example waste from forestry) or from further processing biofuels (for example ethanol).<br/>Whilst synthetic fuels can be “dropped in” to existing engines they are currently more expensive than fossil fuels and in the case of efuels could be thought of as an inefficient use of renewable electricity. However where renewable electricity is cheap and plentiful the manufacture and export of bulk efuels might make economic sense.<br/>Key research challenges identified include improving the fundamental understanding of catalysis; the need to produce cheap low-carbon hydrogen at scale; and developing sources of competitively priced low carbon energy are key to the development of synthetic efuels and biofuels. The UK has the research skills and capacity to improve many of these process steps such as in catalysis and biotechnology and to provide a further area of UK leadership in low-carbon energy.
Simulation Methodology for an Off-grid Solar–battery–water Electrolyzer Plant: Simultaneous Optimization of Component Capacities and System Control
Oct 2021
Publication
The capacity of each component in an off-grid water electrolyzer hydrogen production plant integrated with solar photovoltaics and a battery energy storage system represents a significant factor affecting the viability and reliability of the system. This paper describes a novel method that optimizes simultaneously the component capacities and finite-state machine based control of the system to minimize the cost of green hydrogen production. The components and control in the system are referenced to a proton exchange membrane water electrolyzer stack with a fixed nominal power of 4.5 kW. The end results are thus scalable by changing the nominal power of the electrolyzer. Simulations are carried out based on data collected from a residential solar photovoltaic installation with 300 s time resolution. Optimization of the system is performed with particle swarm optimization algorithm. A sensitivity analysis performed over the prices of the different components reveals that the price of the water electrolyzer has the greatest impact on the green hydrogen production cost. It is found that the price of the battery has to be below 0.3 e/Wh to become a feasible solution as overnight energy storage.
Hydrogen: Enabling A Zero-Emission Society
Nov 2021
Publication
Discover the colours of hydrogen debunk the myths around hydrogen and learn the facts and key moments in history for hydrogen as well as innovative technologies ground-breaking projects state-of-the-art research development and cooperation by members of Hydrogen Europe
Heat Recovery from a PtSNG Plant Coupled with Wind Energy
Nov 2021
Publication
Power to substitute natural gas (PtSNG) is a promising technology to store intermittent renewable electricity as synthetic fuel. Power surplus on the electric grid is converted to hydrogen via water electrolysis and then to SNG via CO2 methanation. The SNG produced can be directly injected into the natural gas infrastructure for long-term and large-scale energy storage. Because of the fluctuating behaviour of the input energy source the overall annual plant efficiency and SNG production are affected by the plant operation time and the standby strategy chosen. The re-use of internal (waste) heat for satisfying the energy requirements during critical moments can be crucial to achieving high annual efficiencies. In this study the heat recovery from a PtSNG plant coupled with wind energy based on proton exchange membrane electrolysis adiabatic fixed bed methanation and membrane technology for SNG upgrading is investigated. The proposed thermal recovery strategy involves the waste heat available from the methanation unit during the operation hours being accumulated by means of a two-tanks diathermic oil circuit. The stored heat is used to compensate for the heat losses of methanation reactors during the hot-standby state. Two options to maintain the reactors at operating temperature have been assessed. The first requires that the diathermic oil transfers heat to a hydrogen stream which is used to flush the reactors in order to guarantee the hot-standby conditions. The second option entails that the stored heat being recovered for electricity production through an Organic Rankine Cycle. The electricity produced is used to compensate the reactors heat losses by using electrical trace heating during the hot-standby hours as well as to supply energy to ancillary equipment. The aim of the paper is to evaluate the technical feasibility of the proposed heat recovery strategies and how they impact on the annual plant performances. The results showed that the annual efficiencies on an LHV basis were found to be 44.0% and 44.3% for the thermal storage and electrical storage configurations respectively.
Recent Developments of Membranes and Electrocatalysts for the Hydrogen Production by Anion Exchange Membrane Water Electrolysers: A Review
Nov 2022
Publication
Hydrogen production using anion exchange membrane water electrolysis (AEMWE) offers hope to the energy crisis faced by humanity. AEM electrolysis can be coupled with intermittent and renewable energy sources as well as with the use of low-cost electrocatalysts and other low-cost stack components. In AEM water electrolysis one of the biggest advantages is the use of low-cost transition metal catalysts instead of traditional noble metal electrocatalysts. AEMWE is still in its infancy despite irregular research on catalysts and membranes. In order to generate commercially viable hydrogen AEM water electrolysis technology must be further developed including energy efficiency membrane stability stack feasibility robustness ion conductivity and cost reduction. An overview of studies that have been conducted on electrocatalysts membranes and ionomers used in the AEMWEs is here reported with the aim that AEMWE research may be made more practical by this review report by bridging technological gaps and providing practical research recommendations leading to the production of scalable hydrogen.
The Path to Net Zero and Progress on Reducing Emissions in Wales
Dec 2020
Publication
These two joint reports required under the Environment (Wales) Act 2016 provide ministers with advice on Wales’ climate targets between now and 2050 and assess progress on reducing emissions to date. Our advice to the Welsh Government is set out in two parts:
Advice Report: The path to a Net Zero Wales provides recommendations on the actions that are needed in Wales including the legislation of a Net Zero target and package of policies to deliver it.
Progress Report: Reducing emissions in Wales looks back at the progress made in Wales since the 2016 Environment (Wales) Act was passed and assesses whether Wales is on track to meet its currently legislated emissions reductions targets.
This work is based on an extensive programme of analysis consultation and consideration by the Committee and its staff building on the evidence published last year for our Net Zero report. It is compatible with our advice on the UK’s Sixth Carbon Budget. In support of the advice in this report we have also published:
Advice Report: The path to a Net Zero Wales provides recommendations on the actions that are needed in Wales including the legislation of a Net Zero target and package of policies to deliver it.
Progress Report: Reducing emissions in Wales looks back at the progress made in Wales since the 2016 Environment (Wales) Act was passed and assesses whether Wales is on track to meet its currently legislated emissions reductions targets.
This work is based on an extensive programme of analysis consultation and consideration by the Committee and its staff building on the evidence published last year for our Net Zero report. It is compatible with our advice on the UK’s Sixth Carbon Budget. In support of the advice in this report we have also published:
- All the charts and data behind the report as well as a separate dataset for the scenarios which sets out more details and data on the pathways than can be included in this report.
- A public Call for Evidence several new research projects three expert advisory groups and deep dives into the roles of local authorities and businesses.
Biomass Steam Gasification with In-Situ CO2 Capture for Enriched Hydrogen Gas Production: A Reaction Kinetics Modelling Approach
Aug 2010
Publication
Due to energy and environmental issues hydrogen has become a more attractive clean fuel. Furthermore there is high interest in producing hydrogen from biomass with a view to sustainability. The thermochemical process for hydrogen production i.e. gasification is the focus of this work. This paper discusses the mathematical modeling of hydrogen production process via biomass steam gasification with calcium oxide as sorbent in a gasifier. A modelling framework consisting of kinetics models for char gasification methanation Boudouard methane reforming water gas shift and carbonation reactions to represent the gasification and CO2 adsorption in the gasifier is developed and implemented in MATLAB. The scope of the work includes an investigation of the influence of the temperature steam/biomass ratio and sorbent/biomass ratio on the amount of hydrogen produced product gas compositions and carbon conversion. The importance of different reactions involved in the process is also discussed. It is observed that hydrogen production and carbon conversion increase with increasing temperature and steam/biomass ratio. The model predicts a maximum hydrogen mole fraction in the product gas of 0.81 occurring at 950 K steam/biomass ratio of 3.0 and sorbent/biomass ratio of 1.0. In addition at sorbent/biomass ratio of 1.52 purity of H2 can be increased to 0.98 mole fraction with all CO2 present in the system adsorbed.
Development of Hydrogen Storage Tank Systems Based on Complex Metal Hydrides
Sep 2015
Publication
This review describes recent research in the development of tank systems based on complex metal hydrides for thermolysis and hydrolysis. Commercial applications using complex metal hydrides are limited especially for thermolysis-based systems where so far only demonstration projects have been performed. Hydrolysis-based systems find their way in space naval military and defense applications due to their compatibility with proton exchange membrane (PEM) fuel cells. Tank design modeling and development for thermolysis and hydrolysis systems as well as commercial applications of hydrolysis systems are described in more detail in this review. For thermolysis mostly sodium aluminum hydride containing tanks were developed and only a few examples with nitrides ammonia borane and alane. For hydrolysis sodium borohydride was the preferred material whereas ammonia borane found less popularity. Recycling of the sodium borohydride spent fuel remains an important part for their commercial viability.
Improve Hydrogen Economy for Vehicular Fuel Cell System via Investigation and Control of Optimal Operating Oxygen Excess Ratio
Apr 2022
Publication
This study investigates and controls the optimal operating oxygen excess ratio (OER) for PEMFC which effectively prevents oxygen starvation and improves the hydrogen economy of proton exchange membrane fuel cells (PEMFC). Firstly the PEMFC output characteristic model and the five-order nonlinear air supply system model are established. Moreover an adaptive algebraic observer was developed to observe the partial pressure of gas in PEMFC and further reconstruct OER. Secondly to achieve the minimum hydrogen consumption under the required power the reference OER is determined by analyzing the PEMFC system output power with its minimum current. Finally the super-twisting algorithm is adopted to track reference OER. Simulation results show that the average absolute observation errors of oxygen nitrogen and cathode pressures under the Highway Fuel Economy Test are 1351.1 Pa (5.1%) 1724.2 Pa (0.9%) and 409.9 Pa (1.6%) respectively. The OER adjust average absolute error is 0.03. Compared with the commonly used fixed OER (e.g. OER of 1.5 and 2.3) the optimal OER strategy can reduce the hydrogen consumption of the PEMFC system by 5.2% and 1.8% respectively. Besides a DSP hardware in loop test is conducted to show the real-time performance of the proposed optimal method.
From Post-Combustion Carbon Capture to Sorption-Enhanced Hydrogen Production: A State-of-the-Art Review of Carbonate Looping Process Feasibility
Oct 2018
Publication
Carbon capture and storage is expected to play a pivotal role in achieving the emission reduction targets established by the Paris Agreement. However the most mature technologies have been shown to reduce the net efficiency of fossil fuel-fired power plants by at least 7% points increasing the electricity cost. Carbonate looping is a technology that may reduce these efficiency and economic penalties. Its maturity has increased significantly over the past twenty years mostly due to development of novel process configurations and sorbents for improved process performance. This review provides a comprehensive overview of the calcium looping concepts and statistically evaluates their techno-economic feasibility. It has been shown that the most commonly reported figures for the efficiency penalty associated with calcium looping retrofits were between 6 and 8% points. Furthermore the calcium-looping-based coal-fired power plants and sorption-enhanced hydrogen production systems integrated with combined cycles and/or fuel cells have been shown to achieve net efficiencies as high as 40% and 50–60% respectively. Importantly the performance of both retrofit and greenfield scenarios can be further improved by increasing the degree of heat integration as well as using advanced power cycles and enhanced sorbents. The assessment of the economic feasibility of calcium looping concepts has indicated that the cost of carbon dioxide avoided will be between 10 and 30 € per tonne of carbon dioxide and 10–50 € per tonne of carbon dioxide in the retrofit and greenfield scenarios respectively. However limited economic data have been presented in the current literature for the thermodynamic performance of calcium looping concepts.
Energy Transition: Measurement Needs Within the Hydrogen Industry
Dec 2017
Publication
Hydrogen in the UK is beginning to shift from hypothetical debates to practical demonstration projects. An ever-growing evidence base has showcased how the costs of hydrogen and its barriers to entry are reducing such that it now has practical potential to contribute to the decarbonisation of the UK's energy sector.
Despite this hydrogen has yet to have wide commercial uptake due in part to a number of barriers where measurement plays a critical role. To accelerate the shift towards the hydrogen economy these challenges have been identified and prioritised by NPL.
The report Energy transition: Measurement needs within the hydrogen industry outlines the challenges identified. The highest priority issues are:
This Document can be downloaded from their website
Despite this hydrogen has yet to have wide commercial uptake due in part to a number of barriers where measurement plays a critical role. To accelerate the shift towards the hydrogen economy these challenges have been identified and prioritised by NPL.
The report Energy transition: Measurement needs within the hydrogen industry outlines the challenges identified. The highest priority issues are:
- Material development for fuel cells and electrolysers to reduce costs and assess critical degradation mechanisms – extending lifetime and durability is key to the commercialisation of these technologies.
- Impact assessment of added odorant to hydrogen to aid leak detection. Measurement of its impact during pipeline transportation and on the end-use application (particularly fuel cell technology) will be important to provide assurance that it will not affect lifetime and durability.
- Determination of the blend ratio when hydrogen is mixed with natural gas in the gas grid. Accurate flow rate measurement and validated metering methods are needed to ensure accurate billing of the consumer.
- Measurement of the combustion properties of hydrogen including flame detection and propagation temperature and nitrogen oxides (NOx) emissions should it be used for heat applications to ensure existing and new appliances are suitable for hydrogen.
- Assessment of the suitability of existing gas infrastructure and materials for hydrogen transportation. Building an understanding of what adaptations might need to be made to avoid for example air permeation metal embrittlement and hydrogen leakage.
- Validated techniques for hydrogen storage which will require measurement of the efficiency and capacity of each mechanism through robust metering leakage detection and purity analysis to ensure they are optimised for the storage of hydrogen gas.
This Document can be downloaded from their website
Boosting Carbon Efficiency of the Biomass to Liquid Process with Hydrogen from Power: The Effect of H2/CO Ratio to the Fischer-Tropsch Reactors on the Production and Power Consumption
Jun 2019
Publication
Carbon efficiency of a biomass to liquid process can be increased from ca. 30 to more than 90% by adding hydrogen generated from renewable power. The main reason is that in order to increase the H2/CO ratio after gasification to the value required for Fischer-Tropsch (FT) synthesis the water gas shift reaction step can be avoided; instead a reversed water gas shift reactor is introduced to convert produced CO2 to CO. Process simulations are done for a 46 t/h FT biofuel production unit. Previous results are confirmed and it is shown how the process can be further improved. The effect of changing the H2/CO ratio to the Fischer-Tropsch synthesis reactors is studied with the use of three different kinetic models. Keeping the CO conversion in the reactors constant at 55% the volume of the reactors decreases with increasing H2/CO ratio because the reaction rates increase with the partial pressure of hydrogen. Concurrently the production of C5+ products and the consumption of hydrogen increases. However the power required per extra produced liter fuel also increases pointing at optimum conditions at a H2/CO feed ratio significantly lower than 2. The trends are the same for all three kinetic models although one of the models is less sensitive to the hydrogen partial pressure. Finally excess renewable energy can be transformed to FT syncrude with an efficiency of 0.8–0.88 on energy basis.
Flexible Electricity Use for Heating in Markets with Renewable Energy
Mar 2020
Publication
Using electricity for heating can contribute to decarbonization and provide flexibility to integrate variable renewable energy. We analyze the case of electric storage heaters in German 2030 scenarios with an open-source electricity sector model. We find that flexible electric heaters generally increase the use of generation technologies with low variable costs which are not necessarily renewables. Yet making customary night-time storage heaters temporally more flexible offers only moderate benefits because renewable availability during daytime is limited in the heating season. Respective investment costs accordingly have to be very low in order to realize total system cost benefits. As storage heaters feature only short-term heat storage they also cannot reconcile the seasonal mismatch of heat demand in winter and high renewable availability in summer. Future research should evaluate the benefits of longer-term heat storage.
Dynamic Modeling of a PEM Fuel Cell Power Plant for Flexibility Optimization and Grid Support
Jun 2022
Publication
The transition toward high shares of non-programmable renewable energy sources in the power grid requires an increase in the grid flexibility to guarantee grid reliability and stability. This work developed within the EU project Grasshopper identifies hydrogen Fuel Cell (FC) power plants based on low temperature PEM cells as a source of flexibility for the power grid. A dynamic numerical model of the flexible FC system is developed and tested against experimental data from a 100-kW pilot plant built within the Grasshopper project. The model is then applied to assess the flexible performance of a 1 MW system in order to optimize the scale-up of the pilot plant to the MW-size. Simulations of load-following operation show the flexibility of the plant which can ramp up and down with a ramp rate depending only on an externally imposed limit. Warm-up simulations allow proposing solutions to limit the warm-up time. Of main importance are the minimization of the water inventory in the system and the construction of a compact system which minimizes the distance between the components.
Experimental Investigation on CO2 Methanation Process for Solar Energy Storage Compared to CO2-Based Methanol Synthesis
Jun 2017
Publication
The utilization of the captured CO2 as a carbon source for the production of energy storage media offers a technological solution for overcoming crucial issues in current energy systems. Solar energy production generally does not match with energy demand because of its intermittent and non-programmable nature entailing the adoption of storage technologies. Hydrogen constitutes a chemical storage for renewable electricity if it is produced by water electrolysis and is also the key reactant for CO2 methanation (Sabatier reaction). The utilization of CO2 as a feedstock for producing methane contributes to alleviate global climate changes and sequestration related problems. The produced methane is a carbon neutral gas that fits into existing infrastructure and allows issues related to the aforementioned intermittency and non-programmability of solar energy to be overcome. In this paper an experimental apparatus composed of an electrolyzer and a tubular fixed bed reactor is built and used to produce methane via Sabatier reaction. The objective of the experimental campaign is the evaluation of the process performance and a comparison with other CO2 valorization paths such as methanol production. The investigated pressure range was 2–20 bar obtaining a methane volume fraction in outlet gaseous mixture of 64.75% at 8 bar and 97.24% at 20 bar with conversion efficiencies of respectively 84.64% and 99.06%. The methanol and methane processes were compared on the basis of an energy parameter defined as the spent energy/stored energy. It is higher for the methanol process (0.45) with respect to the methane production process (0.41–0.43) which has a higher energy storage capability.
Sustainability Indicators for the Manufacturing and Use of a Fuel Cell Prototype and Hydrogen Storage for Portable Uses
Oct 2021
Publication
A sustainability assessment regarding the manufacturing process and the use of a new proton exchange membrane fuel cell (PEMFC) specially designed for portable hydrogen applications is presented. The initial fuel cell prototype has been configured by taking into account exclusively technical issues. However a life cycle analysis considering environmental and socioeconomic impacts is crucial to improve the model to develop a more sustainable product. From the environ‐ mental perspective the durability of the system and its efficiency are key elements required to de‐ crease the potential overall impacts. High electricity consumption for manufacturing requires a commitment to the use of renewable energies due to the high current value of the projected impact of climate change (42.5 tonnes of CO2 eq). From the socioeconomic point of view the dependence of imported components required for the synthesis of some materials displaces the effects of value added and employment in Spain potentially concentrating the largest impact on countries such as Singapore Japan and the UK whereas the cell assembly would have a greater benefit for the country of fabrication. These results provide a basis for new research strategies since they can be considered standard values for improving future upgrades of the fuel cell in terms of sustainability.
An Adaptive Renewable Energy Plant (AREP) - To Power Local Premises and Vehicles with 100% Renewables
Aug 2021
Publication
An adaptive response renewable energy plant (AREP) that provides grid balancing services and XeV station fuelling services (where “X” is any type) using renewable energy located in urban centres is described. The AREP has its own primary renewable energy sources and adapts operation in the short term to changing levels of excess or deficient energy on LV and MV electricity grids. The AREP adaptively responds by (1) storing excess energy in batteries for the short term and in hydrogen tanks after energy conversion by electrolysers for the long term; (2) returning power to the grid from either the AREP’s own primary (electron-based) energy sources or batteries and/or from hydrogen via conversion in fuel cells; (3) providing electricity for fast charging BeVs and PHeVs and hydrogen for FCeVs; and (4) exporting excess stored energy as hydrogen to domestic markets. The AREP also adapts over the long term by predictive planning of charging capacity such that the type and capacity of renewable energy equipment is optimised for future operations. A key advantage of this AREP configuration is a flexible “plug and play” capability with modular extension of energy assets. If the AREP footprint is constrained interaction with neighbouring AREPs as a mini-VPP-AREP network can assist in balancing short-term operating requirements. The benefits of this grid balancing and XeV renewable energy filling station or AREP are environmental social and economic through efficient functionality of appropriately sized components. AREPs provide a net zero emissions electricity solution to an existing network with short and long-term storage options as well as a net zero emissions fuel alternative to the transport sector while leveraging existing infrastructure with minimal upfront CAPEX. AREPs can give the flexibility a grid needs to enable high levels of renewable installations while developing green hydrogen production.
Review of Thermochemical Technologies for Water and Energy Integration Systems: Energy Storage and Recovery
Jun 2022
Publication
Thermochemical technologies (TCT) enable the promotion of the sustainability and the operation of energy systems as well as in industrial sites. The thermochemical operations can be applied for energy storage and energy recovery (alternative fuel production from water/wastewater in particular green hydrogen). TCTs are proven to have a higher energy density and long-term storage compared to standard thermal storage technologies (sensible and latent). Nonetheless these require further research on their development for the increasing of the technology readiness level (TRL). Since TCTs operate with the same input/outputs streams as other thermal storages (for instance wastewater and waste heat streams) these may be conceptually analyzed in terms of the integration in Water and Energy Integration System (WEIS). This work is set to review the techno-economic and environmental aspects related to thermochemical energy storage (sorption and reaction-based) and wastewater-to-energy (particular focus on thermochemical water splitting technology) aiming also to assess their potential into WEIS. The exploited technologies are in general proved to be suitable to be installed within the conceptualization of WEIS. In the case of TCES technologies these are proven to be significantly more potential analogues to standard TES technologies on the scope of the conceptualization of WEIS. In the case of energy recovery technologies although a conceptualization of a pathway to produce usable heat with an input of wastewater further study has to be performed to fully understand the use of additional fuel in combustion-based processes.
Conversion of the UK Gas System to Transport Hydrogen
May 2013
Publication
One option to decarbonise residential heat in the UK is to convert the existing natural gas networks to deliver hydrogen. We review the technical feasibility of this option using semistructured interviews underpinned by a literature review and we assess the potential economic benefits using the UK MARKAL energy systems model. We conclude that hydrogen can be transported safely in the low-pressure pipes but we identify concerns over the reduced capacity of the system and the much lower linepack storage compared to natural gas. New hydrogen meters and sensors would have to be fitted to every building in a hydrogen conversion program and appliances would have to be converted unless the government was to legislate to make them hydrogen-ready in advance. Converting the gas networks to hydrogen is a lower-cost residential decarbonisation pathway for the UK than those identified previously. The cost-optimal share of hydrogen is sensitive to the conversion cost and to variations in the capital costs of heat pumps and micro-CHP fuel cells. With such small cost differentials between technologies the decision to convert the networks will also depend on non-economic factors including the relative performance of technologies and the willingness of the government to organise a conversion program.
Power-to-gas in Electricity Markets Dominated by Renewables
Oct 2018
Publication
This paper analyses the feasibility of power-to-gas in electricity markets dominated by renewables. The business case of a power-to-gas plant that is producing hydrogen is evaluated by determining the willingness to pay for electricity and by comparing this to the level and volatility of electricity prices in a number of European day-ahead markets. The short-term willingness to pay for electricity depends on the marginal costs and revenues of the plant while the long-term willingness to pay for electricity also takes into account investment and yearly fixed operational costs and therefore depends on the expected number of operating hours. The latter ultimately determines whether or not large-scale investments in the power-to-gas technology will take place.<br/>We find that power-to-gas plants are not profitable under current market conditions: even under the most optimistic assumptions for the cost and revenue parameters power-to-gas plants need to run for many hours during the year at very low prices (i.e. the long-term willingness to pay for electricity is very low) that do not currently exist in Europe. In an optimistic future scenario regarding investment costs efficiency and revenues of power-to-gas however the long-term willingness to pay for electricity is higher than the lowest recently observed day-ahead electricity prices. When prices remain at this low level investments in power-to-gas can thus become profitable.
The Effect of Hydrogen Containing Fuel Blends Upon Flashback in Swirl Burners
Feb 2011
Publication
Lean premixed swirl combustion is widely used in gas turbines and many other combustion Processes due to the benefits of good flame stability and blow off limits coupled with low NOx emissions. Although flashback is not generally a problem with natural gas combustion there are some reports of flashback damage with existing gas turbines whilst hydrogen enriched fuel blends especially those derived from gasification of coal and/or biomass/industrial processes such as steel making cause concerns in this area. Thus this paper describes a practical experimental approach to study and reduce the effect of flashback in a compact design of generic swirl burner representative of many systems. A range of different fuel blends are investigated for flashback and blow off limits; these fuel mixes include methane methane/hydrogen blends pure hydrogen and coke oven gas. Swirl number effects are investigated by varying the number of inlets or the configuration of the inlets. The well known Lewis and von Elbe critical boundary velocity gradient expression is used to characterise flashback and enable comparison to be made with other available data. Two flashback phenomena are encountered here. The first one at lower swirl numbers involves flashback through the outer wall boundary layer where the crucial parameter is the critical boundary velocity gradient Gf. Values of Gf are of similar magnitude to those reported by Lewis and von Elbe for laminar flow conditions and it is recognised that under the turbulent flow conditions pertaining here actual gradients in the thin swirl flow boundary layer are much higher than occur under laminar flow conditions. At higher swirl numbers the central recirculation zone (CRZ) becomes enlarged and extends backwards over the fuel injector to the burner baseplate and causes flashback to occur earlier at higher velocities. This extension of the CRZ is complex being governed by swirl number equivalence ratio and Reynolds Number. Under these conditions flashback occurs when the cylindrical flame front surrounding the CRZ rapidly accelerates outwards to the tangential inlets and beyond especially with hydrogen containing fuel mixes. Conversely at lower swirl numbers with a modified exhaust geometry hence restricted CRZ flashback occurs through the outer thin boundary layer at much lower flow rates when the hydrogen content of the fuel mix does not exceed 30%. The work demonstrates that it is possible to run premixed swirl burners with a wide range of hydrogen fuel blends so as to substantially minimise flashback behaviour thus permitting wider used of the technology to reduce NOx emissions.
Controlled Autoignition of Hydrogen in a Direct-injection Optical Engine
Mar 2021
Publication
Research into novel internal combustion engines requires consideration of the diversity in future fuels in an attempt to reduce drastically CO2 emissions from vehicles and promote energy sustainability. Hydrogen has been proposed as a possible fuel for future internal combustion engines and can be produced from renewable sources. Hydrogen’s wide flammability range allows higher engine efficiency than conventional fuels with both reduced toxic emissions and no CO2 gases. Most previous work on hydrogen engines has focused on spark-ignition operation. The current paper presents results from an optical study of controlled autoignition (or homogeneous charge compression ignition) of hydrogen in an engine of latest spark-ignition pentroof combustion chamber geometry with direct injection of hydrogen (100 bar). This was achieved by a combination of inlet air preheating in the range 200–400 C and residual gas recirculated internally by negative valve overlap. Hydrogen fuelling was set to various values of equivalence ratio typically in the range / = 0.40–0.63. Crank-angle resolved flame chemiluminescence images were acquired for a series of consecutive cycles at 1000 RPM in order to calculate in-cylinder rates of flame expansion and motion. Planar Laser Induced Fluorescence (LIF) of OH was also applied to record more detailed features of the autoignition pattern. Single and double (i.e. ‘split’ per cycle) hydrogen injection strategies were employed in order to identify the effect of mixture preparation on autoignition’s timing and spatial development. An attempt was also made to review relevant in-cylinder phenomena from the limited literature on hydrogen-fuelled spark-ignition optical engines and make comparisons were appropriate.
Hydrogen is Essential for Sustainability
Nov 2018
Publication
Sustainable energy conversion requires zero emissions of greenhouse gases and criteria pollutants using primary energy sources that the earth naturally replenishes quickly like renewable resources. Solar and wind power conversion technologies have become cost effective recently but challenges remain to manage electrical grid dynamics and to meet end-use requirements for energy dense fuels and chemicals. Renewable hydrogen provides the best opportunity for a zero emissions fuel and is the best feedstock for production of zero emission liquid fuels and some chemical and heat end-uses. Renewable hydrogen can be made at very high efficiency using electrolysis systems that are dynamically operated to complement renewable wind and solar power dynamics. Hydrogen can be stored within the existing natural gas system to provide low cost massive storage capacity that (1) could be sufficient to enable a 100% zero emissions grid; (2) has sufficient energy density for end-uses including heavy duty transport; (3) is a building block for zero emissions fertilizer and chemicals; and (4) enables sustainable primary energy in all sectors of the economy.
Technical Potential of On-site Wind Powered Hydrogen Producing Refuelling Stations in the Netherlands
Aug 2020
Publication
This study assesses the technical potential of wind turbines to be installed next to existing fuelling stations in order to produce hydrogen. Hydrogen will be used for Fuel Cell Vehicle refuelling and feed-in existing local gas grids. The suitable fuelling stations are selected through a GIS assessment applying buffer zones and taking into account risks associated with wind turbine installation next to built-up areas critical infrastructures and ecological networks. It was found that 4.6% of existing fuelling stations are suitable. Further a hydrogen production potential assessment was made using weather station datasets land cover data and was expressed as potential future Fuel Cell Electric Vehicle demand coverage. It was found that for a 30% FCEV drivetrain scenario these stations can produce 2.3% of this demand. Finally a case study was made for the proximity of those stations in existing gas distribution grids.
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