Publications

Safety issues arising from a hydrogen explosion accident in Korea are discussed herein. In order to increase the safety of hydrogen refueling stations (HRSs) the Korea Gas Safety Corporation (KGS) decided to install a damage-mitigation wall also referred to as a barrier around the storage tanks at the HRSs after evaluating the consequences of hypothetical hydrogen explosion accidents based on the characteristics of each HRS. To propose a new regulation related to the barrier installation at the HRSs which can ensure a proper separation distance between the HRS and its surrounding protected facilities in a complex city KGS planned to test various barrier models under hypothetical hydrogen explosion accidents to develop a standard model of the barrier. A numerical simulation to investigate the effect of the recommended barrier during hypothetical hydrogen explosion accidents in the HRS will be performed before installing the barrier at the HRSs. A computational fluid dynamic (CFD) code based on the open-source software OpenFOAM will be developed for the numerical simulation of various accident scenarios. As the first step in the development of the CFD code we conducted a hydrogen vapor cloud explosion test with a barrier in an open space which was conducted by the Stanford Research Institute (SRI) using the modified XiFoam solver in OpenFOAMv1912. A vapor cloud explosion (VCE) accident may occur due to the leakage of gaseous hydrogen or liquefied hydrogen owing to a failure of piping connected to the storage tank in an HRS. The analysis results using the modified XiFoam predicted the peak overpressure variation from the near field to the far field of the explosion site through the barrier with an error range of approximately ±30% if a proper analysis methodology including the proper mesh distribution in the grid model is chosen. In addition we applied the proposed analysis methodology using the modified XiFoam to barrier shapes that varied from that used in the test to investigate its applicability to predict peak overpressure variations with various barrier shapes. Through the application analysis we concluded that the proposed analysis methodology is sufficient for evaluating the safety effect of the barrier which will be recommended through experimental research during VCE accidents at the HRSs.

Low-carbon (green) hydrogen can be generated via water electrolysis using photovoltaic wind hydropower or decarbonized grid electricity. This work quantifies current and future costs as well as environmental burdens of large-scale hydrogen production systems on geographical islands which exhibit high renewable energy potentials and could act as hydrogen export hubs. Different hydrogen production configurations are examined considering a daily hydrogen production rate of 10 tonnes on hydrogen production costs life cycle greenhouse gas emissions material utilization and land transformation. The results demonstrate that electrolytic hydrogen production costs of 3.7 Euro per kg H2 are within reach today and that a reduction to 2 Euro per kg H2 in year 2040 is likely hence approaching cost parity with hydrogen from natural gas reforming even when applying ‘‘historical’’ natural gas prices. The recent surge of natural gas prices shows that cost parity between green and grey hydrogen can already be achieved today. Producing hydrogen via water electrolysis with low costs and low GHG emissions is only possible at very specific locations nowadays. Hybrid configurations using different electricity supply options demonstrate the best economic performance in combination with low environmental burdens. Autonomous hydrogen production systems are especially effective to produce low-carbon hydrogen although the production of larger sized system components can exhibit significant environmental burdens and investments. Some materials (especially iridium) and the availability of land can be limiting factors when scaling up green hydrogen production with polymer electrolyte membrane (PEM) electrolyzers. This implies that decision-makers should consider aspects beyond costs and GHG emissions when designing large-scale hydrogen production systems to avoid risks coming along with the supply of for example scarce materials

The increasing penetration of renewable energies will make new storage technologies indispensable in the future. Power-to-Gas (PtG) is one long-term storage technology that exploits the existing gas infrastructure. However this technology faces technical economic environmental challenges and questions. This contribution presents the final results of a large research project which attempted to address and provide answers to some of these questions for Baden-Württemberg (south west Germany). Three energy scenarios out to 2040 were defined one oriented towards the Integrated Energy and Climate Protection Concept of the Federal State Government and two alternatives. Timely-resolved load profiles for gas and electricity for 2015 2020 2030 and 2040 have been generated at the level of individual municipalities. The profiles include residential and industrial electrical load gas required for heating (conventional and current-controlled CHP) as well as gas and electricity demand for mobility. The installation of rooftop PV-plants and wind power plants is projected based on bottom up cost-potential analyses which account for some social acceptance barriers. Residential load profiles are derived for each municipality. In times with negative residual load the PtG technology could be used to convert electricity into hydrogen or methane. The detailed analysis of four structurally-different model regions delivered quite different results. While in large cities no negative residual load is likely due to the continuously high demand and strong networks rural areas with high potentials for renewables could encounter several thousand hours of negative residual load. A cost-effective operation of PtG would only be possible under favorable conditions including high full load hours a strong reduction in costs and a technical improvement of efficiency. Whilst these conditions are not expected to appear in the short to mid-term but may occur in the long term in energy systems with very high shares of renewable energy sources

The objective of this pre-normative research (PNR) document entitled EU harmonised terminology for hydrogen generated by electrolysis is to present an open and comprehensive compendium of harmonised terminology for electrolysis applications. This report is prepared under the FWC between JRC and FCH2JU as the result of a collaborative effort between European partners from industry research and development (R&D) organisations and academia participating to FCH2JU funded R&D projects6 in electrolysis applications.7 The commonly accepted definitions of terms may be used in RD&D project documents test and measurement methods test procedures and test protocols scientific publications and technical documentation. This compendium is primarily intended for use by those involved in conducting RD&D as well as in drafting and evaluating R&I programme. The terms and definitions presented cover many aspects of electrolysis including materials research modelling design & engineering analysis characterisation measurements laboratory testing prototype development field tests and demonstration as well as quality assurance (QA). Also it contains information useful for others e. g. auditors manufacturer designers system integrators testing centres service providers and educators. In future it may be expanded to account for possible power-to-hydrogen (P2H2) developments in energy storage (ES) particularly electrical energy storage (EES) hydrogen-to-power (H2P) hydrogen-to-industry (H2I) and hydrogen-to-substance (H2X) applications.

Hydrogen fuel cells have been installed in more than 100 facilities and numerous homes in Ulsan hydrogen town in the Republic of Korea. Despite the advantages of hydrogen accidents can still occur near residential areas. Thus appropriate risk mitigation plans should be established. In this study a computational fluid dynamics (CFD) model of natural and forced ventilation is presented as an emergency response to hydrogen leakages in pressure regulator equipment housing. The CFD model is developed and investigated using three vent configurations: UP CROSS and UP-DOWN. The simulation results indicate that the UPDOWN configuration achieves the lowest internal hydrogen concentration out of the three. In addition the relationship between the total vent size and internal hydrogen concentration is determined. A vent size of 12% of the floor area has the lowest hydrogen concentration. The use of nitrogen for forced ventilation during emergencies is proposed to ensure that the hydrogen concentration of the released gas is less than one-fourth of the lower flammability  2 / 25 limit of hydrogen. Compared to natural ventilation the time required to reach safe conditions is decreased when nitrogen forced ventilation is used.

Hydrogen is a bright energy vector that could be crucial to decarbonise and combat climate change. This energy evolution involves several sectors including power backup systems to supply priority facility loads during power outages. As buildings now integrate complex automation domotics and security systems energy backup systems cause interest. A hydrogen-based backup system could supply loads in a multi-day blackout; however the backup system should be sized appropriately to ensure the survival of essential loads and low cost. In this sense this work proposes a sizing of fuel cell (FC) backup systems for low voltage (LV) buildings using the history of power outages. Historical data allows fitting a probability function to determine the appropriate survival of loads. The proposed sizing is applied to a university building with a photovoltaic generation system as a case study. Results show that the sizing of an FC–battery backup system for the installation is 7.6% cheaper than a battery-only system under a usual 330-minutes outage scenario. And 59.3% cheaper in the case of an unusual 48-hours outage scenario. It ensures a 99% probability of supplying essential load during power outages. It evidences the pertinence of an FC backup system to attend to outages of long-duration and the integration of batteries to support the abrupt load variations. This research is highlighted by using historical data from actual outages to define the survival of essential loads with total service probability. It also makes it possible to determine adequate survival for non-priority loads. The proposed sizing is generalisable and scalable for other buildings and allows quantifying the reliability of the backup system tending to the resilience of electrical systems.

Interest in hydrogen as an energy carrier is growing as countries look to reduce greenhouse gas (GHG) emissions in hard-to-abate sectors. Previous works have focused on hydrogen production well-to-wheel analysis of fuel cell vehicles and vehicle refuelling costs and emissions. These studies use high-level estimates for the hydrogen transportation systems that lack sufficient granularity for techno-economic and GHG emissions analysis. In this work we assess and compare the unit costs and emission footprints (direct and indirect) of 32 systems for hydrogen transportation. Process-based models were used to examine the transportation of pure hydrogen (hydrogen pipeline and truck transport of gaseous and liquified hydrogen) hydrogen-natural gas blends (pipeline) ammonia (pipeline) and liquid organic hydrogen carriers (pipeline and rail). We used sensitivity and uncertainty analyses to determine the parameters impacting the cost and emission estimates. At 1000 km the pure hydrogen pipelines have a levelized cost of $0.66/kg H2 and a GHG footprint of 595 gCO2eq/kg H2. At 1000 km ammonia liquid organic hydrogen carrier and truck transport scenarios are more than twice as expensive as pure hydrogen pipeline and hythane and more than 1.5 times as expensive at 3000 km. The GHG emission footprints of pure hydrogen pipeline transport and ammonia transport are comparable whereas all other transport systems are more than twice as high. These results may be informative for government agencies developing policies around clean hydrogen internationally.

Given that conversion efficiencies of incident solar radiation to liquid fuels e.g. H2 are of the order of a few percent or less as quantified by ‘solar to hydrogen’ (STH) economically inexpensive and operationally straightforward ways to boost photo-electrochemcial (PEC) H2 production from solar-driven water splitting are important. In this work externally-applied static electric fields have led to enhanced H2 production in an energy-efficient manner with up to ~30–40% increase in H2 (bearing in mind fieldinput energy) in a prototype open-type solar cell featuring rutile/titania and hematite/iron-oxide (Fe2O3) respectively in contact with an alkaline aqueous medium (corresponding to respective relative increases of STH by ~12 and 16%). We have also performed non-equilibrium ab-initio molecular dynamics in both static electric and electromagnetic (e/m) fields for water in contact with a hematite/iron-oxide (0 0 1) surface observing enhanced break-up of water molecules by up to ~70% in the linear-response régime. We discuss the microscopic origin of such enhanced water-splitting based on experimental and simulation-based insights. In particular we external-field direction at the hematite surfaces and scrutinise properties of the adsorbed water molecules and OH– and H3O+ species e.g. hydrogen bonds between water-protons and the hematite surfaces’ bridging oxygen atoms as well as interactions between oxygen atoms in adsorbed water molecules and underlying iron atoms.

In the fast filling process in order to control the temperature of the vehicle-mounted storage tank not to exceed the upper limit of 85 ◦C it is an effective method to add a hydrogen pre-cooling system upstream of the hydrogenation machine. In this paper Fluent is used to simulate the heat transfer process of high-pressure hydrogen in a shell-and-tube heat exchanger and the phase change process of refrigerant R23. The accuracy of the model is proven by a comparison with the data in the references. Using this model the temperature field and gas volume fraction in the heat transfer process are obtained which is helpful to analyze the heat transfer mechanism. At the same time the influence of hydrogen inlet temperature hydrogen inlet pressure and refrigerant flow rate on the refrigeration performance was studied. The current work shows that the model can be used to determine the best working parameters in the pre-cooling process and reduce the operating cost of the hydrogen refueling station.

This independent cross-party report highlights the key role that political consensus can play in helping to reduce the costs of nuclear power in the UK as well as other low carbon technologies. This political consensus has never been more important than in this ‘defining decade’ for the power sector. The report highlights that an immediate challenge facing the UK’s new build programme is agreeing with the European Commission a regime for supporting new nuclear power. Changing the proposed support package would not be an impossible task if made necessary but maintaining broad political consensus and considering the implications of delay are also important. The State Aid process is an important opportunity for scrutiny with the report demonstrating that shareholders for Hinkley Point C could see bigger returns (19-21%) than those typically expected for PFI projects (12-15%). However it is too early to conclude on the value for money of the Hinkley Point C agreement. Both the negotiation process and the resulting investment contract are important but there has been little transparency over either so far and the negotiations were not competitive. The inquiry calls for more urgency and better coordination in seizing the opportunity to reuse the UK’s plutonium stockpile.



The UK’s stockpile of separated plutonium presents opportunities to tackle a number of national strategic priorities including implementing long term solutions for nuclear waste developing new technologies that could redefine the sector laying the ground for new nuclear power and pursuing nuclear non-proliferation.  Government has identified three ‘credible solutions’ for reuse and the report recommends that it now sets clearer criteria against which to assess options and identifies budgetary requirements to help expediate the process. The report also argues that Government should do more on new nuclear technologies that could redefine the sector – such as considering smaller reactors nuclear for industrial heat or hydrogen production and closed or thorium fuel cycles. The Government’s initial response to a review of nuclear R&D a year ago by the then Chief Scientific Advisor Sir John Beddington has been welcome and it needs to build on this. In particular the UK should capitalise upon its existing expertise and past experience to focus efforts where there is most strategic value. Nulcear waste. Having failed to date the Government must urgently revisit plans for finding a site to store nuclear waste underground for thousands of years. Implementing this is a crucial part of demonstrating that nuclear waste is a manageable challenge. Despite being rejected by Cumbria County Council the continuing strong support amongst communities in West Cumbria for hosting a site is a promising sign.



On affordability the report finds that it is not yet clear which electricity generation technologies will be cheapest in the 2020s and beyond. Coal and gas could get more expensive if fossil fuel and carbon prices rise whilst low carbon technologies could get cheaper as technology costs fall with more deployment. This is the main reason for adopting an ‘all of the above’ strategy including nuclear power until costs become clearer and there is broad consensus behind this general approach.  



On security of supply the inquiry says that deployment of nuclear power is likely to be influenced more by the economics of system balancing rather than technical system balancing challenges which can be met with greater deployment of existing balancing tools. The cost of maintaining system security is likely to mean that the UK maintains at least some baseload capacity such as nuclear power to limit system costs.



On sustainability the report finds that the environmental impacts of nuclear power are comparable to some generation technologies and favourable to others although the long lived nature of some radioactive nuclear waste and the dual use potential of nuclear technology for civil and military applications create unique sustainability challenges which the UK is a world leader in managing.



It is the final report of the Future Electricity Series an independent and cross party inquiry into the UK power sector sponsored by the Institution of Gas Engineers and Managers

The existing literature on the hydrogen supply chains has knowledge gaps. Most studies focus on hydrogen production storage transport and utilisation but neglect ports which are nexuses in the supply chains. To fill the gap this paper focuses on ports' readiness for the upcoming hydrogen international trade. Potential hydrogen exporting and importing ports are screened. Ports' readiness for hydrogen export and import are reviewed from perspectives of infrastructure risk management public acceptance regulations and standards and education and training. The main findings are: (1) liquid hydrogen ammonia methanol and LOHCs are suitable forms for hydrogen international trade; (2) twenty ports are identified that could be first movers; among them twelve are exporting ports and eight are importing ports; (3) ports’ readiness for hydrogen international trade is still in its infancy and the infrastructure construction or renovation risk management measures establishment of regulations and standards education and training all require further efforts.

Under the background of “carbon peaking” and “carbon neutralization” the green transformation of iron and steel enterprises is imminent. The hydrogen-rich smelting technology of blast furnaces is very important for reducing energy consumption and CO2 emission in ironmaking systems and it is one of the important directions of green and low-carbon development of iron and steel enterprises. In this paper the research status of the thermal state reduction mechanism of iron-bearing burden coke degradation behavior and formation of the cohesive zone in various areas of blast furnace after hydrogen-rich smelting is summarized which can make a more clear and comprehensive understanding for the effect of H2 on blast furnace ironmaking. Meanwhile based on the current research situation it is proposed that the following aspects should be further studied in the hydrogen-rich smelting of blast furnaces: (1) the utilization rate of hydrogen and degree of substitution for direct reduction (2) combustion behavior of fuel in raceway (3) control of gas flow distribution in the blast furnace (4) operation optimization of the blast furnace.

In the context of energy conservation and the reduction of CO2 emissions inconsistencies between the inevitable emission of CO2 in traditional hydrogen production methods and eco-friendly targets have become more apparent over time. The catalytic decomposition of methane (CDM) is a novel technology capable of producing hydrogen without releasing CO2 . Since hydrogen produced via CDM is neither blue nor green the term “turquoise” is selected to describe this technology. Notably the by-products of methane cracking are simply carbon deposits with different structures which can offset the cost of hydrogen production cost should they be harvested. However the encapsulation of catalysts by such carbon deposits reduces the contact area between said catalysts and methane throughout the CDM process thereby rendering the continuous production of hydrogen impossible. This paper mainly covers the CDM reaction mechanisms of the three common metal-based catalysts (Ni Co Fe) from experimental and modelling approaches. The by-products of carbon modality and the key parameters that affect the carbon formation mechanisms are also discussed.

Expanding decarbonization efforts beyond the power sector are contingent on cost-effective production of energy carriers like H2 with near-zero life-cycle carbon emissions. Here we assess the levelized cost of continuous H2 supply (95% availability) at industrial-scale quantities (100 tonnes/day) in 2030 from integrating commodity technologies for solar photovoltaics electrolysis and energy storage. Our approach relies on modeling the least-cost plant design and operation that optimize component sizes while adhering to hourly solar availability production requirements and component inter-temporal operating constraints. We apply the model to study H2 production costs spanning the continental United States and through extensive sensitivity analysis explore system configurations that can achieve $2.5/kg levelized costs or less for a range of plausible 2030 technology projections at high-irradiance locations. Notably we identify potential sites and system configurations where PV-electrolytic H2 could substitute natural gas-derived H2 at avoided CO2 costs (%$120/ton) similar to the cost of deploying carbon capture and sequestration.

An opportunity to sequester large amounts of carbon dioxide (CO2) is made possible because hydraulic fracturing is used to produce most of America's natural gas. CO2 could be extracted from natural gas and water using steam methane reforming pressurized to its supercritical phase and used instead of water to fracture additional hydrocarbon-bearing rock. The useful energy carrier that remains is hydrogen with carbon returned to the ground. Research on the use of supercritical CO2 is reviewed with proppant entrainment identified as the major area where technical advances may be needed. The large potential for greenhouse-gas reduction through sequestration of CO2 and avoidance of methane leakage from the natural gas system is quantified.

The assessment of appropriate operational procedures to govern the injection of a hydrogen/natural gas blend into Northern Gas Networks’ (NGN) Winlaton gas distribution network was a key requirement of the HyDeploy2 project. To perform this assessment the review was broken down into two areas procedures upstream of the emergency control valve (owned by NGN) and procedures downstream of the Emergency Control Valve (procedures which would be performed by Gas Safe registered individuals). Assessment of the upstream procedures was led by NGN (own and carry out all upstream procedures on NGN’s gas network) and assessment of the downstream procedures was led by Blue Flame Associates (an industry expert on downstream gas procedures).<br/>Methodologies were adopted to be able to highlight procedures that could potentially be used on the Winlaton trial network during the hydrogen blended gas injection period and if they were impacted by the changing of the gas within the network from natural gas to hydrogen blended gas. This method determined that for downstream gas procedures a total of 56 gas procedures required expert review resulting in 80 technical questions to be assessed and for the upstream gas procedures a total of 80 gas procedures required expert review resulting in 266 technical questions to be assessed.<br/>The operational procedures assessment has led to a determination as to whether a change is or is not required for relevant operational procedures where a basis of concern existed with respect to the injection of hydrogen blended gas. Any requirements to modify an existing procedure has been given in this report referencing the source as to where the detailed analysis for the change/no change recommendation has been given.<br/>The assessment took into account the associated experimental and research carried out as part of the HyDeploy and HyDeploy2 projects such as the assessment of gas characteristics materials impact appliance survey of assets on the Winlaton network and impact of hydrogen blended gas on gas detection equipment references to these studies have been given accordingly to associated impacted operational procedures.<br/>The conclusion of the assessment is that for upstream gas procedures there are some operational procedures that are unchanged some that require an increase in the frequency as to how often they are performed and some procedures which require a technical modification. For downstream domestic gas procedures all procedures applicable to a domestic gas installation were deemed to not be detrimentally affected by the introduction of a 20 mol% hydrogen blend.<br/>For upstream gas procedures an appropriate training package will be built off the back of the results presented in this report and disseminated accordingly to all relevant Operatives that will be responsible for the safety operation and maintenance of the Winlaton network during the hydrogen blend injection period. For downstream gas procedures the Gas Safe community have been fully engaged and informed about the trial.<br/>Click on the supplements tab to view the other documents from this report

The transition to energy systems with a high share of renewable energy depends on the availability of technologies that can connect the physical distances or bridge the time differences between the energy supply and demand points. This study focuses on energy storage technologies due to their expected role in liberating the energy sector from fossil fuels and facilitating the penetration of intermittent renewable sources. The performance of 27 energy storage alternatives is compared considering sustainability aspects by means of data envelopment analysis. To this end storage alternatives are first classified into two clusters: fast-response and long-term. The levelized cost of energy energy and water consumption global warming potential and employment are common indicators considered for both clusters while energy density is used only for fast-response technologies where it plays a key role in technology selection. Flywheel reveals the highest efficiency between all the fast-response technologies while green ammonia powered with solar energy ranks first for long-term energy storage. An uncertainty analysis is incorporated to discuss the reliability of the results. Overall results obtained and guidelines provided can be helpful for both decision-making and research and development purposes. For the former we identify the most appealing energy storage options to be promoted while for the latter we report quantitative improvement targets that would make inefficient technologies competitive if attained. This contribution paves the way for more comprehensive studies in the context of energy storage by presenting a powerful framework for comparing options according to multiple sustainability indicators.

Reducing the carbon emissions from trucks is critical to achieving the carbon peak of road freight. Based on the prediction of truck population and well-to-wheel (WTW) emission analysis of traditional diesel trucks and potential clean trucks including natural gas battery-electric plug-in hybrid electric and hydrogen fuel cell the paper analyzed the total greenhouse gas (GHG) emissions of China's road freight under four scenarios including baseline policy facilitation (PF) technology breakthrough (TB) and PF-TB. The truck population from 2021 to 2035 is predicted based on regression analysis by selecting the data from 2002 to 2020 of the main variables such as the GDP scale road freight turnover road freight volume and the number of trucks. The study forecasts the truck population of different segments such as mini-duty trucks (MiDT) light-duty trucks (LDT) medium-duty trucks (MDT) and heavy-duty trucks (HDT). Relevant WTW emissions data are collected and adopted based on the popular truck in China's market PHEVs have better emission intensity especially in the HDT field which reduces by 51% compared with ICEVs. Results show that the scenario of TB and PF-TB can reach the carbon peak with 0.13% and 1.5% total GHG emissions reduction per year. In contrast the baseline and PF scenario fail the carbon peak due to only focusing on the number of clean trucks while lacking the restrictions on the GHG emission factors of energy and ignoring the improvement of trucks' energy efficiency and the total emissions increased by 29.76% and 16.69% respectively compared with 2020. As the insights adopting clean trucks has an important but limited effect which should coordinate with the transition to low carbon energy and the melioration of clean trucks to reach the carbon peak of road freight in China.

Commonly used materials constituting the core components of polymer electrolyte membrane fuel cells (PEMFCs) including the balance‐of‐plant were classified according to the EU criticality methodology with an additional assessment of hazardousness and price. A life‐cycle assessment (LCA) of the materials potentially present in PEMFC systems was performed for 1  g of each material. To demonstrate the importance of appropriate actions at the end of life (EoL) for critical materials a LCA study of the whole life cycle for a 1‐kW PEMFC system and 20000 operating hours was performed. In addition to the manufacturing phase four different scenarios of hydrogen production were analyzed. In the EoL phase recycling was used as a primary strategy with energy extraction and landfill as the second and third. The environmental impacts for 1 g of material show that platinum group metals and precious metals have by far the largest environmental impact; therefore it is necessary to pay special attention to these materials in the EoL phase. The LCA results for the 1‐kW PEMFC system show that in the manufacturing phase the major environmental impacts come from the fuel cell stack where the majority of the critical materials are used. Analysis shows that only 0.75 g of platinum in the manufacturing phase contributes on average 60% of the total environmental impacts of the manufacturing phase. In the operating phase environmentally sounder scenarios are the hydrogen production with water electrolysis using hydroelectricity and natural gas reforming. These two scenarios have lower absolute values for the environmental impact indicators on average compared with the manufacturing phase of the 1‐kW PEMFC system. With proper recycling strategies in the EoL phase for each material and by paying a lot of attention to the critical materials the environmental impacts could be reduced on average by 37.3% for the manufacturing phase and 23.7% for the entire life cycle of the 1‐kW PEMFC system.

With the combustor burning hydrogen as well as the strongly coupled fuel and cooling system the configuration of a hydrogen-fueled aero engine is more complex than that of a conventional aero engine. The performance and especially the dynamic behavior of a hydrogen-fueled aero engine need to be fully understood for engine system design and optimization. In this paper both the transient modeling and performance analysis of hydrogen-fueled engines are presented. Firstly the models specific to the hydrogen-fueled engine components and systems including the hydrogen-fueled combustor the steam injection system a simplified model for a quick NOx emission assessment and the heat exchangers are developed and then integrated to a conventional engine models. The simulations with both Simulink and Speedgoat-based hardware in the loop system are carried out. Secondly the performance analysis is performed for a typical turbofan engine configuration CF6 and for the two hydrogen-fueled engine configurations ENABLEH2 and HySIITE which are currently under research and development by the European Union and Pratt & Whitney respectively. At last the simulation results demonstrate that the developed transient models can effectively reflect the characteristics of hydrogen burning heat exchanging and NOx emission for hydrogen-fueled engines. In most cases the hydrogen-fueled engines show lower specific fuel consumption lower turbine entry temperature and less NOx emissions compared with conventional engines. For example at max thrust state the advanced hydrogen-fueled engine can reduce the parameters mentioned above by about 68.5% 3.7% and 12.7% respectively (a mean value of two configurations).

This paper presents a mathematical model for a multi-period hydrogen supply chain design problem considering several design features not addressed in other studies. The model is formulated as a mixed-integer program allowing the production and storage facilities to be extended over time. Pipeline and tube trailer transport modes are considered for carrying hydrogen. The model also allows finding the optimal pipeline routes and the number of transport units. The objective is to obtain an efficient supply chain design within a given time frame in a way that the demand and carbon dioxide emissions constraints are satisfied and the total cost is minimized. A computer program is developed to ease the problem-solving process. The computer program extracts the geographical information from Google Maps and solves the problem using an optimization solver. Finally the applicability of the proposed model is demonstrated in a case study from Oman.

Fluctuations in renewable energy production especially from solar and wind plants can be solved by large‐scale energy storage. One of the possibilities is storing energy in the form of hydrogen or methane–hydrogen blends. A viable alternative for storing hydrogen in salt caverns is Lined Rock Cavern (LRC) underground energy storage. One of the most significant challenges in LRC for hydrogen storage is sealing liners which need to have satisfactory sealing and mechanical properties. An experimental study of hydrogen permeability of different kinds of polymers was conducted followed by modeling of hydrogen permeability of these materials with different additives (graphite halloysite and fly ash). Fillers in polymers can have an impact on the hydrogen permeability ratio and reduce the amount of polymer required to make a sealing liner in the reservoir. Results of this study show that hydrogen permeability coefficients of polymers and estimated hydrogen leakage through these materials are similar to the results of salt rock after the salt creep process. During 60 days of hydrogen storage in a tank of 1000 m2 inner surface 1 cm thick sealing liner and gas pressure of 1.0 MPa only approx. 1 m3STP of hydrogen will diffuse from the reservoir. The study also carries out the modeling of the hydrogen permeability of materials using the Max‐ well model. The difference between experimental and model results is up to 17% compared to the differences exceeding 30% in some other studies.

In this paper we will explore the state of play with renewable hydrogen development in Africa through some case studies from AGHA members and the scope for growth moving forward. In so doing we will address some of the prevailing challenges to build out of a clean hydrogen economy that could be foreseen already at this early stage and look for potential solutions building on what is already in place in other sectors. We make the case that there should be four key areas of focus moving forward on African-EU hydrogen collaboration. Firstly (i) foreign direct investment (FDI) should be de-risked through offtake mechanisms and public-private partnerships (ii) flagship projects should lead the way (iii) large parts of the value chain should remain in Africa (iv) wider ‘democratisation’ and accessibility of the sector should be encouraged

As an important component of hydrogen fuel cell vehicles the air compressor with an air foil bearing rotates at tens of thousands of revolutions per minute. The heat generation concentration problem caused by the high-speed motor loss seriously affects the safe and normal operation of the motor so it is very important to clarify the loss distribution of the high-speed motor and adopt a targeted loss reduction design for air compressor heat dissipation. In this paper for an air compressor with a foil bearing with a rated speed of 80000 rpm an empirical formula and a three-dimensional transient magnetic field finite element model are used to model and calculate the air friction loss stator core loss winding loss and permanent magnet eddy current loss. The accuracy of the analytical calculation method is verified by torque test experiments under different revolutions and the average simulation accuracy can reach 91.1%. Then the distribution of the air friction loss stator core loss winding loss and eddy current loss of the air compressor motor at different revolutions is obtained by using this method. The results show that the proposed method can effectively calculate the motor rotor loss of a high-speed air compressor with air foil bearing. Although the motor efficiency increases with the increase in motor speed the absolute value of loss also increases with the increase in motor speed. Stator core loss and air friction loss are the main sources of loss accounting for 55.64% and 29% of the total motor loss respectively. The electromagnetic loss of winding the eddy current and other alloys account for a relatively small proportion which is 15% in total. The conclusions obtained in this paper can effectively guide calculations of motor loss the motor heat dissipation design of a high-speed air compressor with an air foil bearing.

Technology roadmaps are increasingly used by governments to inform and promote technological transitions such as a transition to a hydrogen energy system. This paper develops a framework for understanding how current roadmapping practice relates to emerging theories of the governance of systems innovation. In applying this framework to a case study of hydrogen roadmaps the paper finds that roadmapping for transitions needs to place greater emphasis on ensuring good quality and transparent analytic and participatory procedures. To be most useful roadmaps should be embedded within institutional structures that enable the incorporation of learning and re-evaluation but in practice most transition roadmaps are one-off exercises

To provide an effective energy transition hydrogen is required to decarbonize the hard-toabate industries. As a case study this paper provides a holistic view of the hydrogen energy transition in the United Arab Emirates (UAE). By utilizing the directional distance function undesirable data envelopment analysis model the energy economic and environmental efficiency of UAE sectors are estimated from 2001 to 2020 to prioritize hydrogen sector coupling. Green hydrogen production efficiency is analyzed from 2020 to 2050. The UAE should prioritize the industry and transportation sectors with average efficiency scores of 0.7 and 0.74. The decomposition of efficiency into pure technical efficiency and scale efficiency suggests policies and strategies should target upscaling the UAE’s low-carbon hydrogen production capacity to expedite short-term and overall production efficiency. The findings of this study can guide strategies and policies for the UAE’s low-carbon hydrogen transition. A framework is developed based on the findings of the study.

In this study four energy storage systems (Power-to-Gas-to-Power) were analysed that allow electrolysis products to be fully utilized immediately after they are produced. For each option the electrolysis process was supplied with electricity from a wind farm during the off-peak demand periods. In the first two variants the produced hydrogen was directed to a natural gas pipeline while the third and fourth options assumed the use of hydrogen for synthetic natural gas production. All four variants assumed the use of a gas expander powered by high-temperature exhaust gases generated during gas combustion. In the first two options gas was supplied from a natural gas network while synthetic natural gas produced during methanation was used in the other two options. A characteristic feature of all systems was the combustion of gaseous fuels within a ballast-free oxidant atmosphere without nitrogen which is the fundamental component of air in conventional systems. The fifth variant was a reference for the systems equipped with gas expanders and assumed the use of fuel cells for power generation. To evaluate the individual variants the energy storage efficiency was defined and determined and the calculated overall efficiency ranged from 17.08 to 23.79% which may be comparable to fuel cells.

The energy transition with transformation into predominantly renewable sources requires technology development to secure power production at all times despite the intermittent nature of the renewables. Micro gas turbines (MGTs) are small heat and power generation units with fast startup and load-following capability and are thereby suitable backup for the future’s decentralized power generation systems. Due to MGTs’ fuel flexibility a range of fuels from high-heat to lowheat content could be utilized with different greenhouse gas generation. Developing micro gas turbines that can operate with carbon-free fuels will guarantee carbon-free power production with zero CO2 emission and will contribute to the alleviation of the global warming problem. In this paper the redevelopment of a standard 100-kW micro gas turbine to run with methane/hydrogen blended fuel is presented. Enabling micro gas turbines to run with hydrogen blended fuels has been pursued by researchers for decades. The first micro gas turbine running with pure hydrogen was developed in Stavanger Norway and launched in May 2022. This was achieved through a collaboration between the University of Stavanger (UiS) and the German Aerospace Centre (DLR). This paper provides an overview of the project and reports the experimental results from the engine operating with methane/hydrogen blended fuel with various hydrogen content up to 100%. During the development process the MGT’s original combustor was replaced with an innovative design to deal with the challenges of burning hydrogen. The fuel train was replaced with a mixing unit new fuel valves and an additional controller that enables the required energy input to maintain the maximum power output independent of the fuel blend specification. This paper presents the test rig setup and the preliminary results of the test campaign which verifies the capability of the MGT unit to support intermittent renewable generation with minimum greenhouse gas production. Results from the MGT operating with blended methane/hydrogen fuel are provided in the paper. The hydrogen content varied from 50% to 100% (volume-based) and power outputs between 35 kW to 100kW were tested. The modifications of the engine mainly the new combustor fuel train valve settings and controller resulted in a stable operation of the MGT with NOx emissions below the allowed limits. Running the engine with pure hydrogen at full load has resulted in less than 25 ppm of NOx emissions with zero carbon-based greenhouse gas production.

Currently transitioning from fossil fuels to renewable sources of energy is needed considering the impact of climate change on the globe. From this point of view there is a need for development in several stages such as storage transmission and conversion of power. In this paper we demonstrate a simulation of a hybrid energy storage system consisting of a battery and fuel cell in parallel operation. The novelty in the proposed system is the inclusion of an electrolyser along with a switching algorithm. The electrolyser consumes electricity to intrinsically produce hydrogen and store it in a tank. This implies that the system consumes electricity as input energy as opposed to hydrogen being the input fuel. The hydrogen produced by the electrolyser and stored in the tank is later utilised by the fuel cell to produce electricity to power the load when needed. Energy is therefore stored in the form of hydrogen. A battery of lower capacity is coupled with the fuel cell to handle transient loads. A parallel control algorithm is developed to switch on/off the charging and discharging cycle of the fuel cell and battery depending upon the connected load. Electrically equivalent circuits of a polymer electrolyte membrane electrolyser polymer electrolyte membrane fuel cell necessary hydrogen oxygen water tanks and switching controller for the parallel operation were modelled with their respective mathematical equations in MATLAB® Simulink®. In this paper we mainly focus on the modelling and simulation of the proposed system. The results showcase the simulated system’s mentioned advantages and compare its ability to handle loads to a battery-only system.

The environment is seriously threatened by the rising energy demand and the use of conventional energy sources. Renewable energy sources including hydro solar and wind have been the focus of extensive research due to the proliferation of energy demands and technological advancement. Wind energy is mostly harvested in coastal areas and little work has been done on energy extraction from winds in a suburban environment. The fickle behavior of wind makes it a less attractive renewable energy source. However an energy storage method may be added to store harvested wind energy. The purpose of this study is to evaluate the feasibility of extracting wind energy in terms of hydrogen energy in a suburban environment incorporating artificial intelligence techniques. To this end a site was selected latitude 33.64◦ N longitude 72.98◦ N and elevation 500 m above mean sea level in proximity to hills. One year of wind data consisting of wind speed wind direction and wind gust was collected at 10 min intervals. Subsequently long short-term memory (LSTM) support vector regression (SVR) and linear regression models were trained on the empirically collected data to estimate daily hydrogen production. The results reveal that the overall prediction performance of LSTM was best compared to that of SVR and linear regression models. Furthermore we found that an average of 6.76 kg/day of hydrogen can be produced by a 1.5 MW wind turbine with the help of an artificial intelligence method (LSTM) that is well suited for time-series data to classify process and predict.

Owing to the complexity of the sector industrial activities are often represented with limited technological resolution in integrated energy system models. In this study we enriched the technological description of industrial activities in the integrated energy system analysis optimisation (IESA-Opt) model a peer-reviewed energy system optimisation model that can simultaneously provide optimal capacity planning for the hourly operation of all integrated sectors. We used this enriched model to analyse the industrial decarbonisation of the Netherlands for four key activities: high-value chemicals hydrocarbons ammonia and steel production. The analyses performed comprised 1) exploring optimality in a reference scenario; 2) exploring the feasibility and implications of four extreme industrial cases with different technological archetypes namely a bio-based industry a hydrogen-based industry a fully electrified industry and retrofitting of current assets into carbon capture utilisation and storage; and 3) performing sensitivity analyses on key topics such as imported biomass hydrogen and natural gas prices carbon storage potentials technological learning and the demand for olefins. The results of this study show that it is feasible for the energy system to have a fully bio-based hydrogen-based fully electrified and retrofitted industry to achieve full decarbonisation while allowing for an optimal technological mix to yield at least a 10% cheaper transition. We also show that owing to the high predominance of the fuel component in the levelled cost of industrial products substantial reductions in overnight investment costs of green technologies have a limited effect on their adoption. Finally we reveal that based on the current (2022) energy prices the energy transition is cost-effective and fossil fuels can be fully displaced from industry and the national mix by 2050

In recent years the stability of the distribution network has declined due to the large proportion of the uses of distributed generation (DG) with the continuous development of renewable energy power generation technology. Meanwhile the traditional distribution network operation mode cannot keep the balance of the source and load. The operation mode of the active distribution network (ADN) can effectively reduce the decline in operation stability caused by the high proportion of DG. Therefore this work proposes a bi-layer model for the planning of the electricity–hydrogen hybrid energy storage system (ESS) considering demand response (DR) for ADN. The upper layer takes the minimum load fluctuation maximum user purchase cost satisfaction and user comfort as the goals. Based on the electricity price elasticity matrix model the optimal electricity price formulation strategy is obtained for the lower ESS planning. In the lower layer the optimal ESS planning scheme is obtained with the minimum life cycle cost (LCC) of ESS the voltage fluctuation of ADN and the load fluctuation as the objectives. Finally the MOPSO algorithm is used to test the model and the correctness of the proposed method is verified by the extended IEEE-33 node test system. The simulation results show that the fluctuation in the voltage and load is reduced by 62.13% and 37.06% respectively.

New energy vehicles (NEVs) especially electric vehicles (EVs) address the important task of reducing the greenhouse effect. It is particularly important to measure the environmental efficiency of new energy vehicles and the life cycle analysis (LCA) model provides a comprehensive evaluation method of environmental efficiency. To provide researchers with knowledge regarding the research trends of LCA in NEVs a total of 282 related studies were counted from the Web of Science database and analyzed regarding their research contents research preferences and research trends. The conclusion drawn from this research is that the stages of energy resource extraction and collection carrier production and energy transportation maintenance and replacement are not considered to be research links. The stages of material equipment and car transportation and operation equipment settling and forms of use need to be considered in future research. Hydrogen fuel cell electric vehicles (HFCEVs) vehicle type classification the water footprint battery recovery and reuse and battery aging are the focus of further research and comprehensive evaluation combined with more evaluation methods is the direction needed for the optimization of LCA. According to the results of this study regarding EV and hybrid power vehicles (including plug-in hybrid electric vehicles (PHEV) fuel-cell electric vehicles (FCEV) hybrid electric vehicles (HEV) and extended range electric vehicles (EREV)) well-to-wheel (WTW) average carbon dioxide (CO2 ) emissions have been less than those in the same period of gasoline internal combustion engine vehicles (GICEV). However EV and hybrid electric vehicle production CO2 emissions have been greater than those during the same period of GICEV and the total CO2 emissions of EV have been less than during the same period of GICEV.

In the case of a severe nuclear power plant accident hydrogen gas formation may occur from the core degradation and cooling water evaporation and subsequent oxidation of zircaloy. These phenomena increase the risk of hazardous combustion events in the reactor especially when combined with an ignition source. If not handled carefully these types of accidents can cause severe damage to the reactor building with potential radioactive effects on the environment. Although hydrogen-air combustion has been investigated before hydrogen-air-steam mixtures remain unstudied under reactor-like conditions. Thus this study investigated such mixtures’ combustion regimes. A closed tube of 318 liters (7.65m tall and 0.23m inner diameter) measures the flame speed flame propagation and shock wave behaviors for 11-15 %vol hydrogen mixtures combined with 0 20 or 30 %vol steam and air. Thus both the effect of steam and hydrogen content was investigated and compared. The experimental setup combined photomultiplier tubes pressure sensors and shock detectors to give a full view of the different combustion regimes. A number of obstacles changed the in-chamber turbulence during flame propagation to provide further reactor-like environments. This changed turbulence affected the combustion regimes and enhanced the flame speed for some cases. The results showed varying combustion behaviors depending on the water vapor concentration where a higher concentration meant a lower flame speed reduced pressure load and sometimes combustion extinction. At 0 %vol steam dilution the flame speed remained supersonic for all H2 concentrations while at 30 %vol steam dilution the flame speed remained subsonic for all H2 concentrations. Thus with high levels of steam dilution the risk for shock waves leading to potential reactor building destruction decreases."

During the study of the CEN/TC 237 standards “Gas meters” in the European Metrology Programme for Innovation and Research (EMPIR) project named NEWGASMET the impact of the renewable gases (biogas biomethane hydrogen syngas and mixtures with natural gas) on the uncertainty on the gas meter was discussed and described in several recommendation reports. This report is on the activity A2.1.15 where the objective is “Using input from A2.1.2-A2.1.8 FORCE with support from Cesame CMI NEL PTB VSL and ISSI will write a report on the effects of renewable gases on the uncertainty budgets of gas meters.”

Hydrogen (H2) is a low-carbon carrier. Hence measuring the impact of its supply chain is key to guaranteeing environmental benefits. This research proposes a classification of H2 in Colombia based on its carbon footprint and source. Such environmental characterization enables the design of regulatory instruments to incentivize the demand for low carbon-H2. Life cycle assessment (LCA) was used to determine the carbon footprint of H2 production technologies. Based on our LCA four classes of H2 were defined based on the emission threshold: (i) gray-H2 (21.8 - 17.0 kg CO2-eq/kg H2) (ii) low carbon-H2 (4.13 – 17.0 kg CO2-eq/kg H2) (iii) blue-H2 (<4.13 kg CO2-eq/kg H2) and (iv) green-H2 (<4.13 kg CO2-eq/kg H2). While low carbon-H2 could be employed to reduce 22% of the national greenhouse gas (GHG) emissions as defined in the National Determined Contribution (NDC) both blue and green-H2 could be employed for national and international trade since the standard emissions are aligned with international schemes such as CertifHy and the Chinese model. Besides gasification of biomass results in environmental savings indicating that biomass is a promising feedstock for international and local trade. Furthermore combinations of H2 production technologies such as renewable-based electrolysis natural gas steam reforming with CCS and ethanol conversion were evaluated to explore the production of a combination of green- and blue-H2 to meet the current and future demand of low carbon emission H2 in Colombia. However to comply with the proposed carbon emission threshold the installed capacities of solar and wind energies must be increase.

Carbon dioxide is an important medium of the global carbon cycle and has the dual properties of realizing the conversion of organic matter in the ecosystem and causing the greenhouse effect. The fixed or available carbon dioxide in the atmosphere is defined as “gray carbon” while the carbon dioxide that cannot be fixed or used and remains in the atmosphere is called “black carbon”. Carbon neutral is the consensus of human development but its implementation still faces many challenges in politics resources technology market and energy structure etc. It is proposed that carbon replacement carbon emission reduction carbon sequestration and carbon cycle are the four main approaches to achieve carbon neutral among which carbon replacement is the backbone. New energy has become the leading role of the third energy conversion and will dominate carbon neutral in the future. Nowadays solar energy wind energy hydropower nuclear energy and hydrogen energy are the main forces of new energy helping the power sector to achieve low carbon emissions. “Green hydrogen” is the reserve force of new energy helping further reduce carbon emissions in industrial and transportation fields. Artificial carbon conversion technology is a bridge connecting new energy and fossil energy effectively reducing the carbon emissions of fossil energy. It is predicted that the peak value of China’s carbon dioxide emissions will reach 110108 t in 2030. The study predicts that China's carbon emissions will drop to 22108 t 33108 t and 44108 t respectively in 2060 according to three scenarios of high medium and low levels. To realize carbon neutral in China seven implementation suggestions have been put forward to build a new “three small and one large” energy structure in China and promote the realization of China's energy independence strategy.

Fuel transition can decarbonize shipping and help meet IMO 2050 goals. In this paper HFO with CCS LNG with CCS bio-methanol biodiesel hydrogen ammonia and electricity were studied using empirical ship design models from a fleet-level perspective and at the Tank-ToWake level to assist operators technology developers and policy makers. The cargo attainment rate CAR (i.e. cargo that must be displaced due to the low-C propulsion system) the ES (i.e. TTW energy needed per ton*n.m.) the CS (economic cost per ton*n.m.) and the carbon intensity index CII (gCO2 per ton*n.m.) were calculated so that the potential of the various alternatives can be compared quantitatively as a function of different criteria. The sensitivity of CAR towards ship type fuel type cargo type and voyage distance were investigated. All ship types had similar CAR estimates which implies that considerations concerning fuel transition apply equally to all ships (cargo containership tankers). Cargo type was the most sensitive factor that made a ship either weight or volume critical indirectly impacting on the CAR of different fuels; for example a hydrogen ship is weight-critical and has 2.3% higher CAR than the reference HFO ship at 20000 nm. Voyage distance and fuel type could result in up to 48.51% and 11.75% of CAR reduction. In addition to CAR the ES CS and CII for a typical mission were calculated and it was found that HFO and LNG with CCS gave about 20% higher ES and CS than HFO and biodiesel had twice the cost while ammonia methanol and hydrogen had 3–4 times the CS of HFO and electricity about 20 times suggesting that decarbonisation of the world’s fleet will come at a large cost. As an example of including all factors in an effort to create a normalized scoring system an equal weight was allocated to each index (CAR ES CS and CII). Biodiesel achieved the highest score (80%) and was identified as the alternative with the highest potential for a deep-seagoing containership followed by ammonia hydrogen bio-methanol and CCS. Electricity has the lowest normalized score of 33%. A total of 100% CAR is achievable by all alternative fuels but with compromises in voyage distance or with refuelling. For example a battery containership carrying an equal amount of cargo as an HFO-fuelled containership can only complete 13% of the voyage distance or needs refuelling seven times to complete 10000 n.m. The results can guide decarbonization strategies at the fleet level and can help optimise emissions as a function of specific missions.

Nowadays decarbonization of energy economy is a topical theme and several pathways are under discussion. Gaseous fuels will play a primary role during this transition and the production of renewable or low carbon-impact gaseous fuels is necessary to deal with this challenge. Decarbonization will be sustained by an increasing share of renewables which production intermittency can be critical for the energy system. Renewable hydrogen generation is a viable solution since this energy vector can be produced from electricity with a fast response and injected in the existing natural gas infrastructures granting storage capacity and easy transport. Parallelly to the renewable-based energy production fossil-based energy can be exploited with a low carbon impact using methane from reservoirs to produce hydrogen capturing CO2. The mentioned scenarios will lead to hydrogen enrichment of natural gas which impact on the infrastructures is being actively studied. The effect on end-user devices instead is poorly analysed but is fundamental to be assessed. This paper highlights the impact on the widely used premixed condensing boilers which will be fired with hydrogen enriched natural gas in the near future and the changes required to components.

Liquid hydrogen (LH2) has the potential to form part of the UK energy strategy in the future and therefore could see widespread use due to the relatively high energy density when compared to other renewable energy sources. To study the feasibility of this the European Fuel Cells and Hydrogen Joint Undertaking (FCH JU) funded project PRESLHY undertook pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. Several key scenarios were identified as knowledge gaps and both theoretical and experimental studies were conducted to provide insight into these scenarios. This included experiments studying the effect of congestion on an ignited hydrogen plume that develops from a release of LH2; this paper describes the objectives experimental setup and a summary of the results from these activities. Characterisation of the LH2 release hydrogen concentration and temperatures measurements within the resulting gas cloud was undertaken along with pressure measurements both within the cloud and further afield. Various release conditions and congestion levels were studied. Results showed that at high levels of congestion increased overpressures occurred with the higher flow rates studied including one high order event. Data generated from these experiments is being taken forward to generate and validate theoretical models ultimately to contribute to the development of regulations codes and standards (RCS) for LH2."

This study reports on an innovative press-loaded blister hybrid system equipped with gas-chromatography (PBS-GC) that is designed to evaluate the mechanical fatigue of two representative types of commercial Nafion membranes under relevant PEMFC operating conditions (e.g. simultaneously controlling temperature and humidity). The influences of various applied pressures (50 kPa 100 kPa etc.) and blistering gas types (hydrogen oxygen etc.) on the mechanical resistance loss are systematically investigated. The results evidently indicate that hydrogen gas is a more effective blistering gas for inducing dynamic mechanical losses of PEM. The changes in proton conductivity are also measured before and after hydrogen gas pressure-loaded blistering. After performing the mechanical aging test a decrease in proton conductivity was confirmed which was also interpreted using small angle X-ray scattering (SAXS) analysis. Finally an accelerated dynamic mechanical aging test is performed using the homemade PBS-GC system where the hydrogen permeability rate increases significantly when the membrane is pressure-loaded blistering for 10 min suggesting notable mechanical fatigue of the PEM. In summary this PBS-GC system developed in-house clearly demonstrates its capability of screening and characterizing various membrane candidates in a relatively short period of time (<1.5 h at 50 kPa versus 200 h).

An eco-friendly green synthesis of mesoporous iron oxide (hematite) using pomegranate peels through a low-cost and massive product method was investigated. The mass of pomegranate peels was varied to control the morphology of the produced hematite (Fe2O3). The structures textures and optical properties of the products were investigated by FTIR XRD FE-SEM and UV–Vis spectroscopy. Three different Fe2O3 morphologies were obtained; Fe2O3(I) nanorod like shape Fe2O3(II) nanoparticles and Fe2O3(III) nanoporous structured layer. The bandgap values for Fe2O3 (I) (II) and (III) were 2.71 2.95 and 2.29 eV respectively. The newly hematite samples were used as promising photoelectrodes supported on graphite substrate for the photoelectrochemical (PEC) water splitting toward the efficient production of solar hydrogen. The number of generated hydrogen moles was calculated per active area to be 50 molh−1 cm−2 for electrode III which decreased to 15.3molh−1 cm−2 for electrode II. The effects of temperature (30–70 ◦C) on the PEC behavior of the three electrodes were addressed. Different thermodynamic parameters were calculated for the three electrodes which showed activation energies of 13.4 16.8 and 15.2 kJmol−1 respectively. The electrode stability was addressed as a function of the number of runs and exposure time in addition to electrochemical impedance study. Finally the conversion efficiency of the incident photon to-current(IPCE) was estimated under the monochromatic illumination. The optimum value was ∼11% @ 390nm for Fe2O3(III) electrode

Solid oxide fuel cells are an emerging energy conversion technology suitable for high-temperature power generation with proper auxiliary heat. Combining SOFCs and polygeneration has produced practical applications for modern energy system designs. Even though many researchers have reviewed these systems’ technologies opportunities and challenges reviews regarding the optimal strategy for designing and operating the systems are limited. Polygeneration is more complicated than any other energy generation type due to its ability to generate many types of energy from various prime movers. Moreover integration with other applications such as vehicle charging and fueling stations increases the complication in making the system optimally serve the loads. This study elaborates on the energy planning and guidelines for designing a polygeneration system especially for residential applications. The review of polygeneration technologies also aligns with the current research trend of developing green technology for modern and smart homes in residential areas. The proposed guideline is expected to solve the complication in other applications and technologies and design the polygeneration system optimally.

This article proposes a new model of power supply for mobile low power machines applications between 10 W and 30 W such as radio-controlled (RC) electric cars. This power supply is based on general hydrogen from residual aluminum and water with NaOH so it is proposed energy valorization of aluminum waste. In the present research a theoretical model allows us to predict the requested aluminum surface and the required flow of hydrogen has been developed also considering in addition to the geometry and purity of the material two key variables as the temperature and the molarity of the alkaline solution used in the hydrogen production process. Focusing on hydrogen production isopropyl alcohol plays a key role in the reactor’s fuel cell vehicle as it filters out NaOH particles and maintains a constant flow of hydrogen for the operation of the machine keeping the reactor temperature controlled. Finally a comparison of the theoretical and experimental data has been used to validate the developed model using aluminum sheets from ring cans to generate hydrogen which will be used as a source of hydrogen in a power fuel cell of an RC car. Finally the manuscript shows the parts of the vehicle’s powertrain its behavior and mode of operation.

This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government’s national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA the authors have analysed the technology sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options including demand response and energy storage. Hydrogen also becomes an important energy carrier notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH2) the use of hydrogen increases especially in the built environment.

The price of constructing hydrogen generation units is very high and sometimes it is not possible to build them in the desired location so the transfer of hydrogen from the hydrogen generation system to the units that need it is justified. Since the storage of hydrogen gas needs a large volume and its transportation is very complex so if hydrogen is stored in liquid form this problem can be resolved. In transporting liquid hydrogen (LH2) over long distances owing to heat transfer to the environment the LH2 vaporizes forming boil-off gas (BOG). Herein in lieu of only reliquifying the BOG this study proposes and assesses a system employing the BOG partially as feed for a novel liquefaction process and also the remaining utilized in a proton exchange membrane fuel cell (PEMFC) to generate power. Using the cold energy of the onsite liquid oxygen utility of the LH2 cargo vessel the mixed refrigerant liquefaction cycle is further cooled down. In this regard by using 130 kg/h BOG as input 60.37 kg/h of liquid hydrogen is produced and the rest enters PEMFC with 552.7 kg/h oxygen to produce 1592 kW of power. The total thermal efficiency of the integrated system and electrical efficiency of the PEMFC is 83.18% and 68.76% respectively. Regarding the liquefaction cycle its specific power consumption (SPC) and coefficient of performance (COP) were achieved at 3.203 kWh/kgLH2 and 0.1876 respectively. The results of exergy analysis show that the exergy destruction of the whole system is 937.4 kW and also its exergy efficiency is calculated to be 58.38%. Exergoeconomic and Markov analyses have also been applied to the integrated system. Also by changing the important parameters of PEMFC its optimal performance has been extracted.

This paper describes a generic and systematic method to calculate the efficiency and the annual performance for Power-to-Gas (PtG) systems. This approach gives the basis to analytically compare different PtG systems using different technologies under different boundary conditions. To have a comparable basis for efficiency calculations a structured break down of the PtG system is done. Until now there has not been a universal approach for efficiency calculations. This has resulted in a wide variety of efficiency calculations used in feasibility studies and for business-case calculations. For this the PtG system is divided in two sub-systems: the electrolysis and the methanation. Each of the two sub-systems consists of several subsystem boundary levels. Staring from the main unit i.e. the electrolysis stack and/or methanation reactor further units that are required to operate complete PtG system are considered with their respective subsystem boundary conditions. The paper provides formulas how the efficiency of each level can be calculated and how efficiency deviations can be integrated which are caused by the extended energy flow calculations to and from energy users and thermal losses. By this a sensitivity analysis of the sub-systems can be gained and comprehensive goal functions for optimizations can be defined. In a second step the annual performance of the system is calculated as the ratio of useable output and energetic input over one year. The input is the integral of the annual need of electrical and thermal energy of a PtG system depending on the different operation states of the plant. The output is the higher heating value of the produced gas and – if applicable – heat flows that are used externally. The annual performance not only evaluates the steady-state operating efficiency under full load but also other states of the system such as cold standby or service intervals. It is shown that for a full system operation assessment and further system concept development the annual performance is of much higher importance than the steady-state system efficiency which is usually referred to. In a final step load profiles are defined and the annual performance is calculated for a specific system configuration. Using this example different operation strategies are compared.

Britain’s Hydrogen Blending Delivery Plan which sets out how all five of Britain’s gas grid companies will meet the Government’s target for Britain’s network of gas pipes to be ready to deliver 20% hydrogen to homes and businesses from 2023 as a replacement for natural gas.

Hydrogen production by electrolysis is considered an essential means of consuming renewable energy in the future. However the current assessment of the potential of renewable energy electrolysis for hydrogen production is relatively simple and the perspective is not comprehensive. Here we established a Combined Wind and Solar Electrolytic Hydrogen system considering the influence of regional wind-solar-load characteristics and transmission costs to evaluate the hydrogen production potential of 31 provincial-level regions in China in 2050. The results show that in 2050 the levelized cost of hydrogen (LCOH) in China’s provincial regions will still be higher than 10 ¥/kg which is not cost-competitive compared to the current hydrogen production from fossil fuels. It is more cost-effective to deploy wind turbines than photovoltaic in areas with similar wind and solar resources or rich in wind resources. Wind-solar differences impact LCOH equipment capacity configuration and transmission cost composition while load fluctuation significantly impacts LCOH and electricity storage configuration. In addition the sensitivity analysis of 11 technical and economic parameters showed differences in the response performance of LCOH changes to different parameters and the electrolyzer conversion efficiency had the most severe impact. The analysis of subsidy policy shows that for most regions (except Chongqing and Xizang) subsidizing the unit investment cost of wind turbines can minimize LCOH. Nevertheless from the perspective of comprehensive subsidy effect subsidy cost and hydrogen energy development it is more cost-effective to take subsidies for electrolysis equipment with the popularization of hydrogen

In this third episode Steffan Eldred and Hannah Abson from Innovate UK KTN are exploring the scale of the opportunity that hydrogen and aviation present alongside their special guest Katy Milne Head of Industrial Strategy at FlyZero.

The podcast can be found on their website