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Operation of a Solid Oxide Fuel Cell Based Power System with Ammonia as a Fuel: Experimental Test and System Design
Nov 2020
Publication
Ammonia has strong potentialities as sustainable fuel for energy applications. NH3 is carbon free and can be synthetized from renewable energy sources (RES). In Solid Oxide Fuel Cells NH3 reacts electrochemically thereby avoiding the production of typical combustion pollutants such as NOx. In this study an ammonia-fueled solid oxide fuel cells (SOFC) system design is proposed and a thermodynamic model is developed to evaluate its performance. A SOFC short stack was operated with NH3 in a wide range of conditions. Experimental results are implemented in the thermodynamic model. Electrical efficiency of 52.1% based on ammonia Lower Heating Value is calculated at a net power density of 0.36 W cmFC −2 . The operating conditions of the after burner and of the ammonia decomposition reactor are studied by varying the values of specific parameters. The levelized cost of energy of 0.221 $ kWh−1 was evaluated as introduced by the International Energy Agency for a system that operates at nominal conditions and at a reference power output of 100 kW. This supports the feasibility of ammonia-fueled SOFC systems with reference to the carbon free energy market specifically considering the potential development of green ammonia production.
Safety Issues of a Hydrogen Refueling Station and a Prediction for an Overpressure Reduction by a Barrier Using OpenFOAM Software for an SRI Explosion Test in an Open Space
Oct 2022
Publication
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.
IGEM/TD/1 Edition 6 Supplement 2 - High Pressure Hydrogen Pipelines
Nov 2021
Publication
This Supplement gives additional requirements and qualifications for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) pipelines to Hydrogen service. For the purposes of this document any NG/H blend above 10% MOL is considered to be an equivalence to 100% hydrogen. For blends below 10% MOL there is no evidence to confirm that blends containing up to 10 mol.% hydrogen do not cause material degradation but it is considered that the risk is low.
This Supplement covers the design construction inspection testing operation and maintenance of steel pipelines and certain associated installations in Hydrogen service and the repurposing of NG pipelines to Hydrogen service at maximum operating pressure (MOP) exceeding 7 bar and not exceeding 137.9 bar.
This standard can be purchased here
This Supplement covers the design construction inspection testing operation and maintenance of steel pipelines and certain associated installations in Hydrogen service and the repurposing of NG pipelines to Hydrogen service at maximum operating pressure (MOP) exceeding 7 bar and not exceeding 137.9 bar.
This standard can be purchased here
Large-scale Hydrogen Production via Water Electrolysis: A Techno-economic and Environmental Assessment
Jul 2022
Publication
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
Methanol as a Renewable Energy Carrier: An Assessment of Production and Transportation Costs for Selected Global Locations
Jun 2021
Publication
The importing of renewable energy will be one part of the process of defossilizing the energy systems of countries and regions which are currently heavily dependent on the import of fossil-based energy carriers. This study investigates the possibility of importing renewable methanol comprised of hydrogen and carbon dioxide. Based on a methanol synthesis simulation model the net production costs of methanol are derived as a function of hydrogen and carbon dioxide expenses. These findings enable a comparison of the import costs of methanol and hydrogen. For this the hydrogen production and distribution costs for 2030 as reported in a recent study for four different origin/destination country combinations are considered. With the predicted hydrogen production costs of 1.35–2 €/kg and additional shipping costs methanol can be imported for 370–600 €/t if renewable or process-related carbon dioxide is available at costs of 100 €/t or below in the hydrogen-producing country. Compared to the current fossil market price of approximately 400 €/t renewable methanol could therefore become cost-competitive. Within the range of carbon dioxide prices of 30–100 €/t both hydrogen and methanol exhibit comparable energy-specific import costs of 18–30 €/GJ. Hence the additional costs for upgrading hydrogen to methanol are balanced out by the lower shipping costs of methanol compared to hydrogen. Lastly a comparison for producing methanol in the hydrogen’s origin or destination country indicates that carbon dioxide in the destination country must be 181–228 €/t less expensive than that in the origin country to balance out the more expensive shipping costs for hydrogen.
Spatially-resolved Analysis of the Challenges and Opportunities of Power-to-Gas (PtG) in Baden-Württemberg until 2040
Mar 2017
Publication
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
On the Potential of Blue Hydrogen Production in Colombia: A Fossil Resource-Based Assessment for Low-Emission Hydrogen
Sep 2022
Publication
Latin America is starting its energy transition. In Colombia with its abundant natural resources and fossil fuel reserves hydrogen (H2 ) could play a key role. This contribution analyzes the potential of blue H2 production in Colombia as a possible driver of the H2 economy. The study assesses the natural resources available to produce blue H2 in the context of the recently launched National Hydrogen Roadmap. Results indicate that there is great potential for low-emission blue H2 production in Colombia using coal as feedstock. Such potential besides allowing a more sustainable use of non-renewable resources would pave the way for green H2 deployment in Colombia. Blue H2 production from coal could range from 700 to 8000 ktH2 /year by 2050 under conservative and ambitious scenarios respectively which could supply up to 1.5% of the global H2 demand by 2050. However while feedstock availability is promising for blue H2 production carbon dioxide (CO2 ) capture capacities and investment costs could limit this potential in Colombia. Indeed results of this work indicate that capture capacities of 15 to 180 MtCO2 /year (conservative and ambitious scenarios) need to be developed by 2050 and that the required investment for H2 deployment would be above that initially envisioned by the government. Further studies on carbon capture utilization and storage capacity implementation of a clear public policy and a more detailed hydrogen strategy for the inclusion of blue H2 in the energy mix are required for establishing a low-emission H2 economy in the country.
EU Harmonised Terminology for Hydrogen Generated by Electrolysis
Jul 2021
Publication
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.
Environmental Impact Assessment of Hydrogen Production via Steam Methane Reforming Based on Emissions Data
Oct 2022
Publication
Steam methane reforming (SMR) using natural gas is the most commonly used technology for hydrogen production. Industrial hydrogen production contributes to pollutant emissions which may differ from the theoretical estimates due to process conditions type and state of installed pollution control equipment. The aim of this study was to estimate the impacts of hydrogen production using facilitylevel real emissions data collected from multiple US EPA databases. The study applied the ReCiPe2016 impact assessment method and considered 12 midpoint and 14 endpoint impacts for 33 US SMR hydrogen production facilities. Global warming impacts were mostly driven by CO2 emissions and contributed to 94.6% of the endpoint impacts on human health while global warming impact on terrestrial ecosystems contributed to 98.3% of the total endpoint impacts on ecosystems. The impacts estimated by direct emissions from the 33 facilities were 9.35 kg CO2e/kg H2 which increased to 11.2 kg CO2e/kg H2 when the full life cycle of hydrogen production including upstream emissions was included. The average global warming impact could be reduced by 5.9% and 11.1% with increases in hydrogen production efficiency by 5% and 10% respectively. Potential impact reductions are also found when natural gas hydrogen production feedstock is replaced by renewable sources with the greatest reduction of 78.1% found in hydrogen production via biomass gasification followed by 68.2% reduction in landfill gas and 53.7% reduction in biomethane-derived hydrogen production.
CFD Modeling on Natural and Forced Ventilation During Hydrogen Leaks in a Pressure Regulator Process of a Residential Area
Mar 2022
Publication
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.
Sizing and Performance Analysis of Hydrogen- and Battery-Based Powertrains, Integrated into a Passenger Train for a Regional Track, Located in Calabria (Italy)
Aug 2022
Publication
In order to decarbonize the rail industry the development of innovative locomotives with the ability to use multiple energy sources constituting hybrid powertrains plays a central role in transitioning from conventional diesel trains. In this paper four configurations based on suitable combinations of fuel cells and/or batteries are designed to replace or supplement a diesel/overhead line powertrain on a real passenger train (the Hitachi Blues) tested on an existing regional track the Catanzaro Lido–Reggio Calabria line (Italy) managed by Trenitalia SpA. (Italy). The configurations (namely battery–electrified line full-battery fuel cell–battery–electrified line and fuel cell–battery) are first sized with the intention of completing a round trip then integrated on board with diesel engine replacement in mind and finally occupy a portion of the passenger area within two locomotives. The achieved performance is thoroughly examined in terms of fuel cell efficiency (greater than 47%) hydrogen consumption (less than 72 kg) braking energy recovery (approximately 300 kWh) and battery interval SOC.
Sizing of a Fuel Cell–battery Backup System for a University Building Based on the Probability of the Power Outages Length
Jul 2022
Publication
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.
Pathways for Low-Carbon Transition of the Steel Industry—A Swedish Case Study
Jul 2020
Publication
The concept of techno-economic pathways is used to investigate the potential implementation of CO2 abatement measures over time towards zero-emission steelmaking in Sweden. The following mitigation measures are investigated and combined in three pathways: top gas recycling blast furnace (TGRBF); carbon capture and storage (CCS); substitution of pulverized coal injection (PCI) with biomass; hydrogen direct reduction of iron ore (H-DR); and electric arc furnace (EAF) where fossil fuels are replaced with biomass. The results show that CCS in combination with biomass substitution in the blast furnace and a replacement primary steel production plant with EAF with biomass (Pathway 1) yield CO2 emission reductions of 83% in 2045 compared to CO2 emissions with current steel process configurations. Electrification of the primary steel production in terms of H-DR/EAF process (Pathway 2) could result in almost fossil-free steel production and Sweden could achieve a 10% reduction in total CO2 emissions. Finally (Pathway 3) we show that increased production of hot briquetted iron pellets (HBI) could lead to decarbonization of the steel industry outside Sweden assuming that the exported HBI will be converted via EAF and the receiving country has a decarbonized power sector.
Large-scale Long-distance Land-based Hydrogen Transportation Systems: A Comparative Techno-economic and Greenhouse Gas Emission Assessment
Aug 2022
Publication
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.
Carbon-negative Hydrogen from Biomass Using Gas Switching Integrated Gasification: Techno-economic Assessment
Sep 2022
Publication
Ambitious decarbonization pathways to limit the global temperature rise to well below 2 ◦C will require largescale CO2 removal from the atmosphere. One promising avenue for achieving this goal is hydrogen production from biomass with CO2 capture. The present study investigates the techno-economic prospects of a novel biomass-to-hydrogen process configuration based on the gas switching integrated gasification (GSIG) concept. GSIG applies the gas switching combustion principle to indirectly combust off-gas fuel from the pressure swing adsorption unit in tubular reactors integrated into the gasifier to improve efficiency and CO2 capture. In this study these efficiency gains facilitated a 5% reduction in the levelized cost of hydrogen (LCOH) relative to conventional O2-blown fluidized bed gasification with pre-combustion CO2 capture even though the larger and more complex gasifier cancelled out the capital cost savings from avoiding the air separation and CO2 capture units. The economic assessment also demonstrated that advanced gas treatment using a tar cracker instead of a direct water wash can further reduce the LCOH by 12% and that the CO2 prices in excess of 100 €/ton consistent with ambitious decarbonization pathways will make this negative-emission technology economically highly attractive. Based on these results further research into the GSIG concept to facilitate more efficient utilization of limited biomass resources can be recommended.
Electric-field-promoted Photo-electrochemical Production of Hydrogen from Water Splitting
Jul 2021
Publication
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.
Photocatalytic Hydrogen Evolution from Biomass Conversion
Feb 2021
Publication
Biomass has incredible potential as an alternative to fossil fuels for energy production that is sustainable for the future of humanity. Hydrogen evolution from photocatalytic biomass conversion not only produces valuable carbon-free energy in the form of molecular hydrogen but also provides an avenue of production for industrially relevant biomass products. This photocatalytic conversion can be realized with efficient sustainable reaction materials (biomass) and inexhaustible sunlight as the only energy inputs. Reported herein is a general strategy and mechanism for photocatalytic hydrogen evolution from biomass and biomass-derived substrates (including ethanol glycerol formic acid glucose and polysaccharides). Recent advancements in the synthesis and fundamental physical/mechanistic studies of novel photocatalysts for hydrogen evolution from biomass conversion are summarized. Also summarized are recent advancements in hydrogen evolution efciency regarding biomass and biomass-derived substrates. Special emphasis is given to methods that utilize unprocessed biomass as a substrate or synthetic photocatalyst material as the development of such will incur greater benefts towards a sustainable route for the evolution of hydrogen and production of chemical feedstocks.
Research on High-Pressure Hydrogen Pre-Cooling Based on CFD Technology in Fast Filling Process
Dec 2021
Publication
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.
Fostering Macroeconomic Research on Hydrogen-Powered Aviation: A Systematic Literature Review on General Equilibrium Models
Feb 2023
Publication
Hydrogen is a promising fuel to decarbonize aviation but macroeconomic studies are currently missing. Computable general equilibrium (CGE) models are suitable to conduct macroeconomic analyses and are frequently employed in hydrogen and aviation research. The main objective of this paper is to investigate existing CGE studies related to (a) hydrogen and (b) aviation to derive a macroeconomic research agenda for hydrogen-powered aviation. Therefore the well-established method of systematic literature review is conducted. First we provide an overview of 18 hydrogen-related and 27 aviation-related CGE studies and analyze the literature with respect to appropriate categories. Second we highlight key insights and identify research gaps for both the hydrogen and aviation-related CGE literature. Our findings comprise inter alia hydrogen’s current lack of cost competitiveness and the macroeconomic relevance of air transportation. Research gaps include among others a stronger focus on sustainable hydrogen and a more holistic perspective on the air transportation system. Third we derive implications for macroeconomic research on hydrogen-powered aviation including (I) the consideration of existing modeling approaches (II) the utilization of interdisciplinary data and scenarios (III) geographical suitability (IV) the application of diverse policy tools and (V) a holistic perspective. Our work contributes a meaningful foundation for macroeconomic studies on hydrogen-powered aviation. Moreover we recommend policymakers to address the macroeconomic perspectives of hydrogen use in air transportation.
Future Electricity Series Part 3 - Power from Nuclear
Mar 2014
Publication
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 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
Everything About Hydrogen Podcast: The Other Hydrogen Vehicle?
Oct 2019
Publication
For this episode we speak to Amanda Lyne the Managing Director of ULEMCo and the Chair of the UK Hydrogen and Fuel Cell Association (UKHFCA). Below are a few links to some of the content discussed on the show and some further background reading.
The podcast can be found on their website
The podcast can be found on their website
A Review on Ports' Readiness to Facilitate International Hydrogen Trade
Jan 2023
Publication
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.
Moving Toward the Low-carbon Hydrogen Economy: Experiences and Key Learnings from National Case Studies
Sep 2022
Publication
The urgency to achieve net-zero carbon dioxide (CO2) emissions by 2050 as first presented by the IPCC special report on 1.5°C Global Warming has spurred renewed interest in hydrogen to complement electrification for widespread decarbonization of the economy. We present reflections on estimates of future hydrogen demand optimization of infrastructure for hydrogen production transport and storage development of viable business cases and environmental impact evaluations using life cycle assessments. We highlight challenges and opportunities that are common across studies of the business cases for hydrogen in Germany the UK the Netherlands Switzerland and Norway. The use of hydrogen in the industrial sector is an important driver and could incentivise large-scale hydrogen value chains. In the long-term hydrogen becomes important also for the transport sector. Hydrogen production from natural gas with capture and permanent storage of the produced CO2 (CCS) enables large-scale hydrogen production in the intermediate future and is complementary to hydrogen from renewable power. Furthermore timely establishment of hydrogen and CO2 infrastructures serves as an anchor to support the deployment of carbon dioxide removal technologies such as direct air carbon capture and storage (DACCS) and biohydrogen production with CCS. Significant public support is needed to ensure coordinated planning governance and the establishment of supportive regulatory frameworks which foster the growth of hydrogen markets.
Effect of H2 on Blast Furnace Ironmaking: A Review
Nov 2022
Publication
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.
Sector Coupling and Business Models Towards Sustainability: The Case of the Hydrogen Vehicle Industry
Mar 2022
Publication
The concept of sector coupling has been gaining increased momentum in political discourses during 18 the past few years but it has only recently received the attention of international academics. The 19 private sector is particularly relevant to foster sector coupling through entrepreneurial action – 20 specifically innovative business models for more sustainable technologies are needed to promote a 21 transition towards more sustainability. So far however the literature on business models from a 22 sector coupling perspective is scarce yet strongly emerging. To address the identified research gaps 23 and enhance the current knowledge on the emerging hydrogen vehicle industry and sector coupling 24 this study adopts a qualitative and exploratory research approach and builds on information gained 25 in 103 semi-structured interviews to discuss emerging business models in Germany. In particular 33 26 business cases have been analyzed. Anchoring business model theory to the concept of sector 27 coupling this study identifies 12 business model archetypes in the emerging hydrogen vehicle 28 industry and its value chain. It can be shown that while the market is still emerging and the market 29 players are not defined and are evolving companies are currently engaged in finding their position 30 along the value chain fostering vertical integration and promoting cooperation between the 31 different sectors. While this study is relevant for both the academia and the industry it is particularly 2 32 interesting for policy makers shaping the future of sustainable development specifically considering 33 integrated energy systems.
Decarbonizing Natural Gas: A Review of Catalytic Decomposition and Carbon Formation Mechanisms
Apr 2022
Publication
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.
Comparative Cost Assessment of Sustainable Energy Carriers Produced from Natural Gas Accounting for Boil-off Gas and Social Cost of Carbon
Jun 2020
Publication
As a result of particular locations of large-scale energy producers and increases in energy demand transporting energy has become one of the key challenges of energy supply. For a long-distance ocean transportation transfer of energy carriers via ocean tankers is considered as a decent solution compared to pipelines. Due to cryogenic temperatures of energy carriers heat leaks into storage tanks of these carriers causes a problem called boil-off gas (BOG). BOG losses reduce the quantity of energy carriers which affects their economic value. Therefore this study proposes to examine the effects of BOG economically in production and transportation phases of potential energy carriers produced from natural gas namely; liquefied natural gas (LNG) dimethyl-ether (DME) methanol liquid ammonia (NH3) and liquid hydrogen (H2). Mathematical approach is used to calculate production and transportation costs of these energy carriers and to account for BOG as a unit cost within the total cost. The results of this study show that transportation costs of LNG liquid ammonia methanol DME and liquid hydrogen from natural gas accounting for BOG are 0.74 $/GJ 1.09 $/GJ 0.68 $/GJ 0.53 $/GJ and 3.24 $/GJ respectively. DME and methanol can be more economic compared to LNG to transport the energy of natural gas for the same ship capacity. Including social cost of carbon (SCC) within the total cost of transporting the energy of natural gas the transportation cost of liquid ammonia is 1.11 $/GJ whereas LNG transportation cost rises significantly to 1.68 $/GJ at SCC of 137 $/t CO2 eq. Consequently liquid ammonia becomes economically favored compared to LNG. Transportation cost of methanol (0.70 $/GJ) and DME (0.55 $/GJ) are also lower than LNG however liquid hydrogen transportation cost (3.24 $/GJ) is still the highest even though the increment of the cost is about 0.1% as SCC included within the transportation cost.
Can Industrial-Scale Solar Hydrogen Supplied from Commodity Technologies Be Cost Competitive by 2030?
Sep 2020
Publication
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.
Improving the Economics of Fossil-free Steelmaking via Co-production of Methanol
Mar 2022
Publication
Steelmaking is responsible for 7% of the global net emissions of carbon dioxide and heavily reducing emissions from currently dominating steelmaking processes is difficult and costly. Recently new steelmaking processes based on the reduction of iron ore with hydrogen (H2) produced via water electrolysis have been suggested. If the electricity input to such processes is fossil-free near-zero carbon dioxide emissions steelmaking is achievable. However the high electricity demand of electrolysis is a significant implementation barrier. A H2 storage may alleviate this via allowing a larger share of H2 to be produced at low electricity prices. However accurately forecasting the dynamics of electricity markets is challenging. This increases the risk of investment in a H2 storage. Here we evaluate a novel methanol-based H2 storage concept for a H2-based steelmaking process that also allows for the coproduction of methanol. During electricity price peaks the methanol can be reformed to produce H2 for the steelmaking process. During prolonged periods of low electricity prices excess methanol can be produced and sold off thus improving the prospects of storage profitability. We use historical electricity prices and a process model to evaluate methanol-fossil-free steel co-production schemes. Methanol coproduction has the potential to improve the economics of H2 supply to a fossil-free steelmaking process by up to an average of 0.40 €/kg H2 across considered scenarios equivalent to a reduction in H2 production electricity costs of 25.0%
Hydrogen Production and Carbon Sequestration by Steam Methane Reforming and Fracking with Carbon Dioxide
Feb 2020
Publication
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.
Analysis of Performance, Emissions, and Lubrication in a Spark-ignition Engine Fueled with Hydrogen Gas Mixtures
Oct 2022
Publication
Hydrogen is one of the main alternative fuels with the greatest potential to replace fossil fuels due to its renewable and environmentally friendly nature. Due to this the present investigation aims to evaluate the combustion characteristics performance parameters emissions and variations in the characteristics of the lubricating oil. The investigation was conducted in a spark-ignition engine fueled by gasoline and hydrogen gas. Four engine load conditions (25% 50% 75% and 100%) and three hydrogen gas mass concentration conditions (3% 6% and 9%) were defined for the study. The investigation results allowed to demonstrate that the injection of hydrogen gas in the gasoline engine causes an increase of 3.2% and 4.0% in the maximum values of combustion pressure and heat release rates. Additionally hydrogen causes a 2.9% increase in engine BTE. Hydrogen's more efficient combustion process allowed for reducing CO HC and smoke opacity emissions. However hydrogen gas causes an additional increase of 14.5% and 30.4% in reducing the kinematic viscosity and the total base number of the lubricating oil. In addition there was evidence of an increase in the concentration of wear debris such as Fe and Cu which implies higher rates of wear in the engine's internal components.
HyDeploy2: Summary of Procedures for the Trial Network
Jun 2021
Publication
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
A Compilation of Operability and Emissions Performance of Residential Water Heaters Operated on Blends of Natural Gas and Hydrogen Including Consideration for Reporting Bases
Feb 2023
Publication
The impact of hydrogen added to natural gas on the performance of commercial domestic water heating devices has been discussed in several recent papers in the literature. Much of the work focuses on performance at specific hydrogen levels (by volume) up to 20–30% as a near term blend target. In the current work new data on several commercial devices have been obtained to help quantify upper limits based on flashback limits. In addition results from 39 individual devices are compiled to help generalize observations regarding performance. The emphasis of this work is on emissions performance and especially NOx emissions. It is important to consider the reporting bases of the emissions numbers to avoid any unitended bias. For water heaters the trends associated with both mass per fuel energy input and concentration-based representation are similar For carbon free fuels bases such as 12% CO2 should be avoided. In general the compiled data shows that NOx NO UHC and CO levels decrease with increasing hydrogen percentage. The % decrease in NOx and NO is greater for low NOx devices (meaning certified to NOx <10 ng/J using premixing with excess air) compared to conventional devices (“pancake burners” partial premixing). Further low NOx devices appear to be able to accept greater amounts of hydrogen above 70% hydrogen in some cases without modification while conventional water heaters appear limited to 40–50% hydrogen. Reporting emissions on a mass basis per unit fuel energy input is preferred to the typical dry concentration basis as the greater amount of water produced by hydrogen results in a perceived increase in NOx when hydrogen is used. While this effort summarizes emissions performance with added hydrogen additional work is needed on transient operation higher levels of hydrogen system durability/reliability and heating efficiency.
Comparative Sustainability Study of Energy Storage Technologies Using Data Envelopment Analysis
Mar 2022
Publication
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.
Progress of Performance, Emission, and Technical Measures of Hydrogen Fuel Internal-Combustion Engines
Oct 2022
Publication
To achieve the goals of low carbon emission and carbon neutrality some urgent challenges include the development and utilization of low-carbon or zero-carbon internal combustion engine fuels. Hydrogen as a clean efficient and sustainable fuel has the potential to meet the abovementioned challenges. Thereby hydrogen internal combustion engines have been attracting attention because of their zero carbon emissions high thermal efficiency high reliability and low cost. In this paper the opportunities and challenges faced by hydrogen internal-combustion engines were analyzed. The progress of hydrogen internal-combustion engines on the mixture formation combustion mode emission reduction knock formation mechanism and knock suppression measures were summarized. Moreover possible technical measures for hydrogen internal-combustion engines to achieve higher efficiency and lower emissions were suggested.
Contribution of Potential Clean Trucks in Carbon Peak Pathway of Road Freight Based on Scenario Analysis: A Case Study of China
Oct 2022
Publication
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.
Numerical Simulation of Hydrogen Deflagration Using CFD
Sep 2021
Publication
Hydrogen is seen as an important future energy carrier as part of the move away from traditional hydrocarbon sources. Delayed ignition of a hydrogen-air mixture formed from an accidental release of hydrogen in either a confined or congested environment can lead to the generation of overpressure impacting both people and assets. An understanding of the possible overpressures generated is critical in designing facilities and effective mitigation systems against hydrogen explosion hazards. This paper describes the numerical modelling of hydrogen deflagrations using a new application PDRFOAM-R that is part of the wider OpenFOAM open-source CFD package of routines for the solution of systems of partial differential equations. The PDRFOAM-R code solves momentum and continuity equations the combustion model is based on flame area transport and the turbulent burning velocity correlation is based on Markstein and Karlovitz numbers. PDRFOAM-R is derived from publicly available PDRFOAM tool and it resolves small and large obstacles unlike PDRFOAM which is based on the Porosity Distributed Resistance approach. The PDRFOAM-R code is validated against various unconfined-uncongested and semi-confined congested explosion experiments. The flame dynamics and pressure history predicted from the simulation show a reasonable comparison with the experiments.
Critical Materials in PEMFC Systems and a LCA Analysis for the Potential Reduction of Environmental Impacts with EoL Strategies
Jul 2019
Publication
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.
Exploring Supply Chain Design and Expansion Planning of China's Green Ammonia Production with an Optimization-based Simulation Approach
Aug 2021
Publication
Green ammonia production as an important application for propelling the upcoming hydrogen economy has not been paid much attention by China the world's largest ammonia producer. As a result related studies are limited. This paper explores potential supply chain design and planning strategies of green ammonia production in the next decade of China with a case study in Inner Mongolia. A hybrid optimization-based simulation approach is applied considering traditional optimization approaches are insufficient to address uncertainties and dynamics in a long-term energy transition. Results show that the production cost of green ammonia will be at least twice that of the current level due to higher costs of hydrogen supply. Production accounts for the largest share of the total expense of green hydrogen (~80 %). The decline of electricity and electrolyser prices are key in driving down the overall costs. In addition by-product oxygen is also considered in the model to assess its economic benefits. We found that by-product oxygen sales could partly reduce the total expense of green hydrogen (~12 % at a price of USD 85/t) but it also should be noted that the volatile price of oxygen may pose uncertainties and risks to the effectiveness of the offset. Since the case study may represent the favourable conditions in China due to the abundant renewable energy resources and large-scale ammonia industry in this region we propose to take a moderate step towards green ammonia production and policies should be focused on reducing the electricity price and capital investments in green hydrogen production. We assume the findings and implications are informative to planning future green ammonia production in China.
Transient Modeling and Performance Analysis of Hydrogen-Fueled Aero Engines
Jan 2023
Publication
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).
Air Mass Flow and Pressure Optimisation of a PEM Fuel Cell Range Extender System
Aug 2022
Publication
In order to eliminate the local CO2 emissions from vehicles and to combat the associated climate change the classic internal combustion engine can be replaced by an electric motor. The two most advantageous variants for the necessary electrical energy storage in the vehicle are currently the purely electrochemical storage in batteries and the chemical storage in hydrogen with subsequent conversion into electrical energy by means of a fuel cell stack. The two variants can also be combined in a battery electric vehicle with a fuel cell range extender so that the vehicle can be refuelled either purely electrically or using hydrogen. The air compressor a key component of a PEM fuel cell system can be operated at different air excess and pressure ratios which influence the stack as well as the system efficiency. To asses the steady state behaviour of a PEM fuel cell range extender system a system test bench utilising a commercially available 30 kW stack (96 cells 409 cm2 cell area) was developed. The influences of the operating parameters (air excess ratio 1.3 to 1.7 stack temperature 20 °C–60 °C air compressor pressure ratio up to 1.67 load point 122 mA/cm2 to 978 mA/cm2) on the fuel cell stack voltage level (constant ambient relative humidity of 45%) and the corresponding system efficiency were measured by utilising current voltage mass flow temperature and pressure sensors. A fuel cell stack model was presented which correlates closely with the experimental data (0.861% relative error). The air supply components were modelled utilising a surface fit. Subsequently the system efficiency of the validated model was optimised by varying the air mass flow and air pressure. It is shown that higher air pressures and lower air excess ratios increase the system efficiency at high loads. The maximum achieved system efficiency is 55.21% at the lowest continuous load point and 43.74% at the highest continuous load point. Future work can utilise the test bench or the validated model for component design studies to further improve the system efficiency.
A Multi-period Sustainable Hydrogen Supply Chain Model Considering Pipeline Routing and Carbon Emissions: The Case Study of Oman
Nov 2022
Publication
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.
Hybrid Renewable Hydrogen Energy Solution for Application in Remote Mines
Dec 2020
Publication
Mining operations in remote locations rely heavily on diesel fuel for the electricity haulage and heating demands. Such significant diesel dependency imposes large carbon footprints to these mines. Consequently mining companies are looking for better energy strategies to lower their carbon footprints. Renewable energies can relieve this over-reliance on fossil fuels. Yet in spite of their many advantages renewable systems deployment on a large scale has been very limited mainly due to the high battery storage system. Using hydrogen for energy storage purposes due to its relatively cheaper technology can facilitate the application of renewable energies in the mining industry. Such cost-prohibitive issues prevent achieving 100% penetration rate of renewables in mining applications. This paper offers a novel integrated renewable–multi-storage (wind turbine/battery/fuel cell/thermal storage) solution with six different configurations to secure 100% off-grid mining power supply as a stand-alone system. A detailed comparison between the proposed configurations is presented with recommendations for implementation. A parametric study is also performed identifying the effect of different parameters (i.e. wind speed battery market price and fuel cell market price) on economics of the system. The result of the present study reveals that standalone renewable energy deployment in mine settings is technically and economically feasible with the current market prices depending on the average wind speed at the mine location.
Permeability Modeling and Estimation of Hydrogen Loss through Polymer Sealing Liners in Underground Hydrogen Storage
Apr 2022
Publication
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.
Underground Bio-methanation: Concept and Potential
Feb 2020
Publication
As a major part of the energy turn around the European Union and other countries are supporting the development of renewable energy technologies to decrease nuclear and fossil energy production. Therefore efficient use of renewable energy resources is one challenge as they are influenced by environmental conditions and hence the intensity of resources such as wind or solar power fluctuates. To secure constant energy supply suitable energy storage and conversion techniques are required. An upcoming solution is the utilization and storage of hydrogen or hydrogen-rich natural gas in porous formations in the underground. In the past microbial methanation was observed as a side effect during these gas storage operations. The concept of underground bio-methanation arised which uses the microbial metabolism to convert hydrogen and carbon dioxide into methane. The concept consists of injecting gaseous hydrogen and carbon dioxide into an underground structure during energy production peaks which are subsequently partly converted into methane. The resulting methane-rich gas mixture is withdrawn during high energy demand. The concept is comparable to engineered bio-reactors which are already locally integrated into the gas infrastructure. In both technologies the conversion process of hydrogen into methane is driven by hydrogenotrophic methanogenic archaea present in the aqueous phase of the natural underground or above-ground engineered reactor. Nevertheless the porous medium in the underground provides compared to the engineered bio-reactors a larger interface between the gas and aqueous phase caused by the enormous volume in the underground porous media. The following article summarizes the potential and concept of underground methanation and the current state of the art in terms of laboratory investigations and pilot tests. A short system potential analysis shows that an underground bio-reactor with a storage capacity of 850 Mio. Sm3 could deliver methane to more than 600000 households based on a hydrogen production from renewable energies.
Redrawing the EU’s Energy Relations: Getting it Right with African Renewable Hydrogen
Oct 2022
Publication
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
Fuel Cell Development for New Energy Vehicles (NEVs) and Clean Air in China
Apr 2018
Publication
This paper reviews the background to New Energy Vehicles (NEV) policies in China and the key scientific and market challenges that need to be addressed to accelerate fuel cells (FCs) in the rapidly developing NEV market. The global significance of the Chinese market key players core FC technologies and future research priorities are discussed.
Research on Motor Rotor Loss of High-Speed Air Compressor in the Application of Hydrogen Fuel Cell Vehicle
Feb 2023
Publication
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.
Feasibility and Impact of a Swedish Fuel Cell-powered Rescue Boat
Jun 2021
Publication
With the increasing interest for zero-emission vehicles electric boats represent a growing area. Weight is a limiting factor for battery-powered boats therefore the use of fuel cell/battery systems is investigated. The present study examines the power requirements the energy-storage solutions and the sustainability assessment of a light and fast rescue boat operating in the Swedish lake Barken. A weight-optimized hybrid fuel cell/battery system is presented. The results show that if the hydrogen storage is wisely selected the weight of the hybrid system is significantly less than that of a battery system and can compete with an internal combustion engine system. The sustainability assessment highlights and compares the impact in terms of cost and emissions of the different energy storage solutions. The quantification of the emissions for the different energy systems under several scenarios shows a clear advantage for the electric solutions.
Technology Roadmaps for Transition Management: The Case of Hydrogen Energy
Oct 2011
Publication
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
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