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Simulation of a Hydrogen-Air Diffusion Flame under Consideration of Component-Specific Diffusivities
Mar 2022
Publication
This work deals with the numerical investigation of a three-dimensional laminar hydrogenair diffusion flame in which a cylindrical fuel jet is surrounded by in-flowing air. To calculate the distribution of gas molecules the model solves the species conservation equation for N-1 components using infinity fast chemistry and irreversible chemical reaction. The consideration of the component-specific diffusion has a strong influence on the position of the high-temperature zone as well as on the concentration distribution of the individual gas molecules. The calculations of the developed model predict the radial and axial species and temperature distribution in the combustion chamber comparable to those from previous publications. Deviations due to a changed burner geometry and air supply narrow the flame structure by up to 50% and the high-temperature zones merge toward the central axis. Due to the reduced inflow velocity of the hydrogen the high-temperature zones develop closer to the nozzle inlet of the combustion chamber. As the power increases the length of the cold hydrogen jet increases. Furthermore the results show that the axial profiles of temperature and mass fractions scale quantitatively with the power input by the fuel.
A Review on Numerical Simulation of Hydrogen Production from Ammonia Decomposition
Jan 2023
Publication
Ammonia (NH3 ) is regarded as a promising medium of hydrogen storage due to its large hydrogen storage density decent performance on safety and moderate storage conditions. On the user side NH3 is generally required to decompose into hydrogen for utilization in fuel cells and therefore it is vital for the NH3 -based hydrogen storage technology development to study NH3 decomposition processes and improve the decomposition efficiency. Numerical simulation has become a powerful tool for analyzing the NH3 decomposition processes since it can provide a revealing insight into the heat and mass transfer phenomena and substantial guidance on further improving the decomposition efficiency. This paper reviews the numerical simulations of NH3 decomposition in various application scenarios including NH3 decomposition in microreactors coupled combustion chemical reactors solid oxide fuel cells and membrane reactors. The models of NH3 decomposition reactions in various scenarios and the heat and mass transport in the reactor are elaborated. The effects of reactor structure and operating conditions on the performance of NH3 decomposition reactor are analyzed. It can be found that NH3 decomposition in microchannel reactors is not limited by heat and mass transfer and NH3 conversion can be improved by using membrane reactors under the same conditions. Finally research prospects and opportunities are proposed in terms of model development and reactor performance improvement for NH3 decomposition.
Green Hydrogen Production by Anion Exchange Membrane Water Electrolysis: Status and Future Perspectives
Jan 2023
Publication
Green hydrogen production i.e. produced on a CO2 -neutral basis through the electrolysis of water employing renewable electricity has attracted increasing attention. The electricity required is generated from Renewable Energy Sources (RES) for example wind energy hydropower or solar energy. Since neither the process of production nor the end products of H2 and O2 are harmful to the environment green hydrogen is climate neutral. Developing electrolysis technology is therefore a research topic to follow. Anion Exchange Membrane (AEM) Water Electrolysis (WE) is an innovative technology that couples the advantages of the more mature technologies of Proton Exchange Membrane (PEM) and conventional alkaline electrolysis with the potential to eliminate the drawbacks of both. AEMWE technology is in an evolutionary stage and involves more investigation on several research topics such as membrane and catalyst development and stability as well as alternative feeding solutions that do not compromise the availability of fresh water. These topics are addressed in this paper mentioning the state-of-the-art materials new promising ones and providing future research directions to improve AEMWE towards a most mature technology.
Optimization of Operating Hydrogen Storage System for Coal–Wind–Solar Power Generation
Jul 2022
Publication
To address the severity of the wind and light abandonment problem and the economics of hydrogen energy production and operation this paper explores the problem of multi-cycle resource allocation optimization of hydrogen storage systems for coal–wind–solar power generation. In view of the seriousness of the problem of abandoning wind and photovoltaic power and the economy of hydrogen production and operation the node selection and scale setting issues for hydrogen production and storage as well as decision-making problems such as the capacity of new transmission lines and new pipelines and route planning are studied. This research takes the satisfaction of energy supply as the basic constraint and constructs a multi-cycle resource allocation optimization model for an integrated energy system aiming to achieve the maximum benefit of the whole system. Using data from Inner Mongolia where wind abandonment and power limitation are severe and Beijing and Shanxi provinces where hydrogen demand is high this paper analyzes the benefits of the hydrogen storage system for coal–wind–solar power generation and explores the impact of national subsidy policies and technological advances on system economics.
Hydrogen-Enriched Compressed Natural Gas Network Simulation for Consuming Green Hydrogen Considering the Hydrogen Diffusion Process
Sep 2022
Publication
Transporting green hydrogen by existing natural gas networks has become a practical means to accommodate curtailed wind and solar power. Restricted by pipe materials and pressure levels there is an upper limit on the hydrogen blending ratio of hydrogen-enriched compressed natural gas (HCNG) that can be transported by natural gas pipelines which affects whether the natural gas network can supply energy safely and reliably. To this end this paper investigates the effects of the intermittent and fluctuating green hydrogen produced by different types of renewable energy on the dynamic distribution of hydrogen concentration after it is blended into natural gas pipelines. Based on the isothermal steady-state simulation results of the natural gas network two convection–diffusion models for the dynamic simulation of hydrogen injections are proposed. Finally the dynamic changes of hydrogen concentration in the pipelines under scenarios of multiple green hydrogen types and multiple injection nodes are simulated on a seven-node natural gas network. The simulation results indicate that compared with the solar-power-dominated hydrogen productionblending scenario the hydrogen concentrations in the natural gas pipelines are more uniformly distributed in the wind-power-dominated scenario and the solar–wind power balance scenario. To be specific in the solar-power-dominated scenario the hydrogen concentration exceeds the limit for more time whilst the overall hydrogen production is low and the local hydrogen concentration in the natural gas network exceeds the limit for nearly 50% of the time in a day. By comparison in the wind-power-dominated scenario all pipelines can work under safe conditions. The hydrogen concentration overrun time in the solar–wind power balance scenario is also improved compared with the solar-power-dominated scenario and the limit-exceeding time of the hydrogen concentration in Pipe 5 and Pipe 6 is reduced to 91.24% and 91.99% of the solar-power-dominated scenario. This work can help verify the day-ahead scheduling strategy of the electricity-HCNG integrated energy system (IES) and provide a reference for the design of local hydrogen production-blending systems.
Electrified Hydrogen Production from Methane for PEM Fuel Cells Feeding: A Review
May 2022
Publication
The greatest challenge of our times is to identify low cost and environmentally friendly alternative energy sources to fossil fuels. From this point of view the decarbonization of industrial chemical processes is fundamental and the use of hydrogen as an energy vector usable by fuel cells is strategic. It is possible to tackle the decarbonization of industrial chemical processes with the electrification of systems. The purpose of this review is to provide an overview of the latest research on the electrification of endothermic industrial chemical processes aimed at the production of H2 from methane and its use for energy production through proton exchange membrane fuel cells (PEMFC). In particular two main electrification methods are examined microwave heating (MW) and resistive heating (Joule) aimed at transferring heat directly on the surface of the catalyst. For cases the catalyst formulation and reactor configuration were analyzed and compared. The key aspects of the use of H2 through PEM were also analyzed highlighting the most used catalysts and their performance. With the information contained in this review we want to give scientists and researchers the opportunity to compare both in terms of reactor and energy efficiency the different solutions proposed for the electrification of chemical processes available in the recent literature. In particular through this review it is possible to identify the solutions that allow a possible scale-up of the electrified chemical process imagining a distributed production of hydrogen and its consequent use with PEMs. As for PEMs in the review it is possible to find interesting alternative solutions to platinum with the PGM (Platinum Group Metal) free-based catalysts proposing the use of Fe or Co for PEM application.
Studies Concerning Electrical Repowering of a Training Airplane Using Hydrogen Fuel Cells
Mar 2024
Publication
The increase in greenhouse gas emissions as well as the risk of fossil fuel depletion has prompted a transition to electric transportation. The European Union aims to substantially reduce pollutant emissions by 2035 through the use of renewable energies. In aviation this transition is particularly challenging mainly due to the weight of onboard equipment. Traditional electric motors with radial magnetic flux have been replaced by axial magnetic flux motors with reduced weight and volume high efficiency power and torque. These motors were initially developed for electric vehicles with in-wheel motors but have been adapted for aviation without modifications. Worldwide there are already companies developing propulsion systems for various aircraft categories using such electric motors. One category of aircraft that could benefit from this electric motor development is traditionally constructed training aircraft with significant remaining flight resource. Electric repowering would allow their continued use for pilot training preparing them for future electrically powered aircraft. This article presents a study on the feasibility of repowering a classic training aircraft with an electric propulsion system. The possibilities of using either a battery or a hybrid source composed of a battery and a fuel cell as an energy source are explored. The goal is to utilize components already in production to eliminate the research phase for specific aircraft components.
A Hydrogen-Fueled Micro Gas Turbine Unit for Carbon-Free Heat and Power Generation
Oct 2022
Publication
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.
An Overview of Promising Alternative Fuels for Road, Rail, Air, and Inland Waterway Transport in Germany
Feb 2022
Publication
To solve the challenge of decarbonizing the transport sector a broad variety of alternative fuels based on different concepts including Power-to-Gas and Power-to-Liquid and propulsion systems have been developed. The current research landscape is investigating either a selection of fuel options or a selection of criteria a comprehensive overview is missing so far. This study aims to close this gap by providing a holistic analysis of existing fuel and drivetrain options spanning production to utilization. For this purpose a case study for Germany is performed considering different vehicle classes in road rail inland waterway and air transport. The evaluated criteria on the production side include technical maturity costs as well as environmental impacts whereas on the utilization side possible blending with existing fossil fuels and the satisfaction of the required mission ranges are evaluated. Overall the fuels and propulsion systems Methanol-to-Gasoline Fischer–Tropsch diesel and kerosene hydrogen battery-electric propulsion HVO DME and natural gas are identified as promising future options. All of these promising fuels could reach near-zero greenhouse gas emissions bounded to some mandatory preconditions. However the current research landscape is characterized by high insecurity with regard to fuel costs depending on the predicted range and length of value chains.
Safe Design of a Hydrogen-Powered Ship: CFD Simulation on Hydrogen Leakage in the Fuel Cell Room
Mar 2023
Publication
Adopting proton exchange membrane fuel cells fuelled by hydrogen presents a promising solution for the shipping industry’s deep decarbonisation. However the potential safety risks associated with hydrogen leakage pose a significant challenge to the development of hydrogen-powered ships. This study examines the safe design principles and leakage risks of the hydrogen gas supply system of China’s first newbuilt hydrogen-powered ship. This study utilises the computational fluid dynamics tool FLACS to analyse the hydrogen dispersion behaviour and concentration distributions in the hydrogen fuel cell room based on the ship’s parameters. This study predicts the flammable gas cloud and time points when gas monitoring points first reach the hydrogen volume concentrations of 0.8% and 1.6% in various leakage scenarios including four different diameters (1 3 5 and 10 mm) and five different directions. This study’s findings indicate that smaller hydrogen pipeline diameters contribute to increased hydrogen safety. Specifically in the hydrogen fuel cell room a single-point leakage in a hydrogen pipeline with an inner diameter not exceeding 3 mm eliminates the possibility of flammable gas cloud explosions. Following a 10 mm leakage diameter the hydrogen concentration in nearly all room positions reaches 4.0% within 6 s of leakage. While the leakage diameter does not impact the location of the monitoring point that first activates the hydrogen leak alarm and triggers an emergency hydrogen supply shutdown the presence of obstructions near hydrogen detectors and the leakage direction can affect it. These insights provide guidance on the optimal locations for hydrogen detectors in the fuel cell room and the pipeline diameters on hydrogen gas supply systems which can facilitate the safe design of hydrogen-powered ships.
Global Potential of Green Ammonia Based on Hybrid PV-wind Power Plants
Apr 2021
Publication
Ammonia is one of the most commonly used feedstock chemicals globally. Therefore decarbonisation of ammonia production is of high relevance towards achieving a carbon neutral energy system. This study investigates the global potential of green ammonia production from semi-flexible ammonia plants utilising a cost-optimised configuration of hybrid PV-wind power plants as well as conversion and balancing technologies. The global weather data used is on an hourly time scale and 0.45◦ × 0.45◦ spatial resolution. The results show that by 2030 solar PV would be the dominating electricity generation technology in most parts of the world and the role of batteries would be limited while no significant role is found for hydrogen-fuelled gas turbines. Green ammonia could be generated at the best sites in the world for a cost range of 440–630 345–420 300–330 and 260–290 €/tNH3 in 2020 2030 2040 and 2050 respectively for a weighted average capital cost of 7%. Comparing this to the decade-average fossil-based ammonia cost of 300–350 €/t green ammonia could become cost-competitive in niche markets by 2030 and substitute fossil-based ammonia globally at current cost levels. A possible cost decline of natural gas and consequently fossil-based ammonia could be fully neutralised by greenhouse gas emissions cost of about 75 €/tCO2 by 2040. By 2040 green ammonia in China would be lower in cost than ammonia from new coal-based plants even at the lowest coal prices and no greenhouse gas emissions cost. The difference in green ammonia production at the least-cost sites in the world’s nine major regions is less than 50 €/tNH3 by 2040. Thus ammonia shipping cost could limit intercontinental trading and favour local or regional production beyond 2040.
Advances in Hydrogen, Carbon Dioxide, and Hydrocarbon Gas Sensor Technology Using GaN and ZnO-Based Devices
Jun 2009
Publication
In this paper we review our recent results in developing gas sensors for hydrogen using various device structures including ZnO nanowires and GaN High Electron Mobility Transistors (HEMTs). ZnO nanowires are particularly interesting because they have a large surface area to volume ratio which will improve sensitivity and because they operate at low current levels will have low power requirements in a sensor module. GaN-based devices offer the advantage of the HEMT structure high temperature operation and simple integration with existing fabrication technology and sensing systems. Improvements in sensitivity recoverability and reliability are presented. Also reported are demonstrations of detection of other gases including CO2 and C2H4 using functionalized GaN HEMTs. This is critical for the development of lab-on-a-chip type systems and can provide a significant advance towards a market-ready sensor application.
Combustion Characterization in a Diffusive Gas Turbine Burner for Hydrogen-Compliant Applications
Jun 2022
Publication
The target of net-zero emissions set by the 2015 Paris Agreement has strongly commissioned the energy production sector to promote decarbonization renewable sources exploitation and systems efficiency. In this framework the utilization of hydrogen as a long-term energy carrier has great potential. This paper is concerned with the combustion characterization in a non-premixed gas turbine burner originally designed for natural gas when it is fed with NG-H2 blends featuring hydrogen content from 0 to 50% in volume. The final aim is to retrofit a 40 MW gas turbine. Starting from the operational data of the engine a CFD model of the steady-state combustion process has been developed with reference to the base load NG conditions by reducing the fuel mass-flow rate by up to 17% to target the baseline turbine inlet temperature. When the fuel is blended with hydrogen for a given temperature at turbine inlet an increase in the peak temperature up to 800 K is obtained if no countermeasures are taken. Furthermore the flame results are more intense and closer to the injector in the case of hydrogen blending. The results of this work hint at the necessity of carefully analyzing the possible NOx compensation strategies as well as the increased thermal stresses on the injector.
On the Climate Impacts of Blue Hydrogen Production
Nov 2021
Publication
Natural gas based hydrogen production with carbon capture and storage is referred to as blue hydrogen. If substantial amounts of CO2 from natural gas reforming are captured and permanently stored such hydrogen could be a low-carbon energy carrier. However recent research raises questions about the effective climate impacts of blue hydrogen from a life cycle perspective. Our analysis sheds light on the relevant issues and provides a balanced perspective on the impacts on climate change associated with blue hydrogen. We show that such impacts may indeed vary over large ranges and depend on only a few key parameters: the methane emission rate of the natural gas supply chain the CO2 removal rate at the hydrogen production plant and the global warming metric applied. State-of-the-art reforming with high CO2 capture rates combined with natural gas supply featuring low methane emissions does indeed allow for substantial reduction of greenhouse gas emissions compared to both conventional natural gas reforming and direct combustion of natural gas. Under such conditions blue hydrogen is compatible with low-carbon economies and exhibits climate change impacts at the upper end of the range of those caused by hydrogen production from renewable-based electricity. However neither current blue nor green hydrogen production pathways render fully “net-zero” hydrogen without additional CO2 removal.
Economic Evaluation of Renewable Hydrogen Integration into Steelworks for the Production of Methanol and Methane
Jun 2022
Publication
This work investigates the cost-efficient integration of renewable hydrogen into steelworks for the production of methane and methanol as an efficient way to decarbonize the steel industry. Three case studies that utilize a mixture of steelworks off-gases (blast furnace gas coke oven gas and basic oxygen furnace gas) which differ on the amount of used off-gases as well as on the end product (methane and/or methanol) are analyzed and evaluated in terms of their economic performance. The most influential cost factors are identified and sensitivity analyses are conducted for different operating and economic parameters. Renewable hydrogen produced by PEM electrolysis is the most expensive component in this scheme and responsible for over 80% of the total costs. Progress in the hydrogen economy (lower electrolyzer capital costs improved electrolyzer efficiency and lower electricity prices) is necessary to establish this technology in the future.
Research on Multi-Period Hydrogen Refueling Station Location Model in Jiading District
Sep 2021
Publication
The construction of hydrogen refueling stations is an important part of the promotion of fuel cell vehicles. In this paper a multi-period hydrogen refueling station location model is presented that can be applied to the planning and construction of hydrogen infrastructures. Based on the hydrogen demand of fuel cell passenger cars and commercial vehicles the model calculates the hydrogen demand of each zone by a weighting method according to population economic level and education level. Then the hydrogen demand of each period is calculated using the generalized Bass diffusion model. Finally the set covering model is improved to determine the locations of the stations. The new model is applied to the scientific planning of hydrogen refueling stations in Jiading District Shanghai; the construction location and sequence of hydrogen refueling stations in each period are given and the growth trend of hydrogen demand and the promoting effect of hydrogen refueling stations are analyzed. The model adopted in this model is then compared with the other two kinds of node-based hydrogen refueling station location models that have previously been proposed.
Recent Development in Nanoconfined Hydrides for Energy Storage
Jun 2022
Publication
Hydrogen is the ultimate vector for a carbon-free sustainable green-energy. While being the most promising candidate to serve this purpose hydrogen inherits a series of characteristics making it particularly difficult to handle store transport and use in a safe manner. The researchers’ attention has thus shifted to storing hydrogen in its more manageable forms: the light metal hydrides and related derivatives (ammonia-borane tetrahydridoborates/borohydrides tetrahydridoaluminates/alanates or reactive hydride composites). Even then the thermodynamic and kinetic behavior faces either too high energy barriers or sluggish kinetics (or both) and an efficient tool to overcome these issues is through nanoconfinement. Nanoconfined energy storage materials are the current state-of-the-art approach regarding hydrogen storage field and the current review aims to summarize the most recent progress in this intriguing field. The latest reviews concerning H2 production and storage are discussed and the shift from bulk to nanomaterials is described in the context of physical and chemical aspects of nanoconfinement effects in the obtained nanocomposites. The types of hosts used for hydrogen materials are divided in classes of substances the mean of hydride inclusion in said hosts and the classes of hydrogen storage materials are presented with their most recent trends and future prospects.
Geological Hydrogen Storage: Geochemical Reactivity of Hydrogen with Sandstone Reservoirs
Jun 2022
Publication
The geological storage of hydrogen is necessary to enable the successful transition to a hydrogen economy and achieve net-zero emissions targets. Comprehensive investigations must be undertaken for each storage site to ensure their long-term suitability and functionality. As such the systematic infrastructure and potential risks of large-scale hydrogen storage must be established. Herein we conducted over 250 batch reaction experiments with different types of reservoir sandstones under conditions representative of the subsurface reflecting expected time scales for geological hydrogen storage to investigate potential reactions involving hydrogen. Each hydrogen experiment was paired with a hydrogen-free control under otherwise identical conditions to ensure that any observed reactions were due to the presence of hydrogen. The results conclusively reveal that there is no risk of hydrogen loss or reservoir integrity degradation due to abiotic geochemical reactions in sandstone reservoirs.
Energy and Utility Skills - Hydrogen Competency Framework Report
Jul 2021
Publication
In 2020 the Department for Business Enterprise and Industrial Strategy (BEIS) commissioned Energy & Utility Skills to develop and deliver a Hydrogen Competency Framework as part of the Hy4Heat programme. The successful completion of this work is detailed in a new report published today.
The work done by Energy & Utility Skills was underpinned by three key pillars:
Collaboration
The resulting outputs of the design development stages are:
More details about this report can be found on the Energy & Utility Skills website.
The work done by Energy & Utility Skills was underpinned by three key pillars:
Collaboration
- Driving growth in engagement levels across the industry
- Designing the framework for both initial trials and any future rollout
- The framework ensures engineers will have all the skills knowledge and understanding they need
The resulting outputs of the design development stages are:
- A Comparative Analysis of Hydrogen and existing hydrocarbon gases
- A Skills Matrix that translates the analysis into skills knowledge and understanding
- An Interim Hydrogen Technical Standard that defines acceptable parameters and requirements for hydrogen installation work
- A Hydrogen Training Specification that will enable training course consistency and facilitate industry recognition
- An independent Hydrogen Assessment Module that will facilitate the addition of a hydrogen competence category on the Gas Safe Register
More details about this report can be found on the Energy & Utility Skills website.
Electrofuels from Excess Renewable Electricity at High Variable Renewable Shares: Cost, Greenhouse Gas Abatement, Carbon Use and Competition
Nov 2020
Publication
Increasing shares of variable renewable electricity (VRE) generation are necessary for achieving high renewable shares in all energy sectors. This results in increased excess renewable electricity (ERE) at times when supply exceeds demand. ERE can be utilized as a low-emission energy source for sector coupling through hydrogen production via electrolysis which can be used directly or combined with a carbon source to produce electrofuels. Such fuels are crucial for the transport sector where renewable alternatives are scarce. However while ERE increases with raising VRE shares carbon emissions decrease and may become a limited resource with several usage options including carbon storage (CCS). Here we perform a model based analysis for the German case until 2050 with a general analysis for regions with a high VRE reliance. Results indicate that ERE-based electrofuels could achieve a greenhouse gas (GHG) abatement of 74 MtCO2eq yearly (46% of current German transport emissions) by displacing fossil fuels at high fuel-cell electric vehicle (FCEV) shares at a cost of 250–320 V per tCO2eq. The capital expenditure of electrolysers was found not to be crucial for the cost despite low capacity factors due to variable ERE patterns. Carbon will likely become a limiting factor when aiming for stringent climate targets and renewable electricity-based hydrocarbon electrofuels replacing fossil fuels achieve up to 70% more GHG abatement than CCS. Given (1) an unsaturated demand for renewable hydrocarbon fuels (2) a saturated renewable hydrogen demand and (3) unused ERE capacities which would otherwise be curtailed we find that carbon is better used for renewable fuel production than being stored in terms of overall GHG abatement.
The Influence of Hydrogen Sulfide Contaminations on Hydrogen Production in Chemical Looping Processes
Aug 2021
Publication
Chemical looping with iron-based oxygen carriers enables the production of hydrogen from various fossil and biogenic primary energy sources. In applications with real producer gases such as biogas or gasified biomass hydrogen sulfide represents one of the most challenging contaminants. The impact of H2S on the reactivity of a Fe2O3/Al2O3 oxygen carrier material in chemical looping hydrogen production was investigated in the present work. First potential sulfur deactivation mechanisms are discussed in detail on the basis of thermodynamic data. Afterwards an experimental study in a fixed-bed reactor system gave experimental evidence on the fate of sulfur in chemical looping hydrogen systems. The chemisorption of hydrogen sulfide (H2S) was identified as the main cause for the accumulative adsorption of H2S in the reduction phase and was confirmed by ex-situ ICP-EOS analysis. In the subsequent steam oxidation step significant quantities of H2S were released resulting in an undesirable contamination of the hydrogen product gas. The reason was found as weakened sulfur bonds through increasing reactor temperatures caused by the exothermic oxidation reactions. In additional air oxidation steps no further contaminants as sulfur dioxide were identified. A profound interpretation was achieved through the fulfillment of the overall sulfur mass balance within a mean deviation of 3.7%. Quantitative investigations showed that the hydrogen consumption decreased by 12% throughout the reduction phase in the event of 100 ppm H2S in the feed gas
The Challenges of Integrating the Principles of Green Chemistry and Green Engineering to Heterogeneous Photocatalysis to Treat Water and Produce Green H2
Jan 2023
Publication
Nowadays heterogeneous photocatalysis for water treatment and hydrogen production are topics gaining interest for scientists and developers from different areas such as environmental technology and material science. Most of the efforts and resources are devoted to the development of new photocatalyst materials while the modeling and development of reaction systems allowing for upscaling the process to pilot or industrial scale are scarce. In this work we present what is known on the upscaling of heterogeneous photocatalysis to purify water and to produce green H2. The types of reactors successfully used in water treatment plants are presented as study cases. The challenges of upscaling the photocatalysis process to produce green H2 are explored from the perspectives of (a) the adaptation of photoreactors (b) the competitiveness of the process and (c) safety. Throughout the text Green Chemistry and Engineering Principles are described and discussed on how they are currently being applied to the heterogeneous photocatalysis process along with the challenges that are ahead. Lastly the role of automation and high-throughput methods in the upscaling following the Green Principles is discussed.
Energy Saving in Public Transport Using Renewable Energy
Jan 2017
Publication
Hydrogen produced by renewable sources represents an interesting way to reduce the energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study for the production storage and distribution of hydrogen in the western Sicilian context using three different renewable sources: wind biomass and sea wave. The objective of this study is the evaluation of the hydrogen demand needed to replace all diesel supplied buses with electrical buses equipped with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the renewable energy resources present in the territories and to the modern technologies available for the production of hydrogen. The study focuses on the possibility of tapping into the potential of renewable energies (wind biomass and sea wave) for the production of hydrogen by electrolysis. The use of hydrogen would reduce significantly the emissions of particulate and greenhouse gases in the urban districts under analysis.
Fuel Flexibility of Solid Oxide Fuel Cells
Aug 2021
Publication
One of the major advantages of SOFCs is their high fuel flexibility. Next to natural gas and hydrogen which are today’s most common fuels for SOFC-systems and cell-/stack-testing respectively various other fuels are applicable as well. In the literature a number of promising results show that available fuels as propane butane ammonia gasoline diesel etc. can be applied. Here the performance of an anode supported cell operated in specialized single cell test benches with different gaseous and liquid fuels and reformates thereof is presented. Fuels as ammonia dissolved urea (AddBlueTM) methane/steam and ethanol/water mixtures can directly be fed to the cell whereas propane and diesel require external reforming. It is shown that in case of a stable fuel supply the cell performance with such fuels is similar to that of appropriate mixtures of H2 N2 CO CO2 and steam if the impact of endothermic reforming or decomposition reactions is considered. Even though a stable fuel cell operation with such fuels is possible in a single cell test bench it should be pointed out that an appropriate fuel processing will be mandatory on the system level.
Energy-Economic Assessment of Islanded Microgrid with Wind Turbine, Photovoltaic Field, Wood Gasifier, Battery, and Hydrogen Energy Storage
Sep 2022
Publication
Island energy systems are becoming an important part of energy transformation due to the growing needs for the penetration of renewable energy. Among the possible systems a combination of different energy generation technologies is a viable option for local users as long as energy storage is implemented. The presented paper describes an energy-economic assessment of an island system with a photovoltaic field small wind turbine wood chip gasifier battery and hydrogen circuit with electrolyzer and fuel cell. The system is designed to satisfy the electrical energy demand of a tourist facility in two European localizations. The operation of the system is developed and dynamically simulated in the Transient System Simulation (TRNSYS) environment taking into account realistic user demand. The results show that in Gdansk Poland it is possible to satisfy 99% of user demand with renewable energy sources with excess energy equal to 31% while in Agkistro Greece a similar result is possible with 43% of excess energy. Despite the high initial costs it is possible to obtain Simple Pay Back periods of 12.5 and 22.5 years for Gdansk and Agkistro respectively. This result points out that under a high share of renewables in the energy demand of the user the profitability of the system is highly affected by the local cost of energy vectors. The achieved results show that the system is robust in providing energy to the users and that future development may lead to an operation based fully on renewables.
A Review of The Methanol Economy: The Fuel Cell Route
Jan 2020
Publication
This review presents methanol as a potential renewable alternative to fossil fuels in the fight against climate change. It explores the renewable ways of obtaining methanol and its use in efficient energy systems for a net zero-emission carbon cycle with a special focus on fuel cells. It investigates the different parts of the carbon cycle from a methanol and fuel cell perspective. In recent years the potential for a methanol economy has been shown and there has been significant technological advancement of its renewable production and utilization. Even though its full adoption will require further development it can be produced from renewable electricity and biomass or CO2 capture and can be used in several industrial sectors which make it an excellent liquid electrofuel for the transition to a sustainable economy. By converting CO2 into liquid fuels the harmful effects of CO2 emissions from existing industries that still rely on fossil fuels are reduced. The methanol can then be used both in the energy sector and the chemical industry and become an all-around substitute for petroleum. The scope of this review is to put together the different aspects of methanol as an energy carrier of the future with particular focus on its renewable production and its use in high-temperature polymer electrolyte fuel cells (HT-PEMFCs) via methanol steam reforming.
Comparative Life Cycle Assessment of Sustainable Energy Carriers Including Production, Storage, Overseas Transport and Utilization
Aug 2020
Publication
Countries are under increasing pressure to reduce greenhouse gas emissions as an act upon the Paris Agreement. The essential emission reductions can be achieved by environmentally friendly solutions in particular the introduction of low carbon or carbon-free fuels. This study presents a comparative life cycle assessment of various energy carriers namely; liquefied natural gas methanol dimethyl ether liquid hydrogen and liquid ammonia that are produced from natural gas or renewables to investigate greenhouse gas emissions generated from the complete life cycle of energy carriers accounting for the leaks as well as boil-off gas occurring during storage and transportation. The entire fuel life cycle is considered consisting of production storage transportation via an ocean tanker to different distances and finally utilization in an internal combustion engine of a road vehicle. The results show that using natural gas as a feedstock total greenhouse gas emissions during production ocean transportation (over 20000 nmi) by a heavy fuel oil-fueled ocean tanker and utilization in an internal combustion engine are 73.96 95.73 93.76 50.83 and 100.54 g CO2 eq. MJ1 for liquified natural gas methanol dimethyl ether liquid hydrogen and liquid ammonia respectively. Liquid hydrogen produced from solar electrolysis is the cleanest energy carrier (42.50 g CO2 eq. MJ1 fuel). Moreover when liquid ammonia is produced via photovoltaic-based electrolysis (60.76 g CO2 eq. MJ1 fuel) it becomes cleaner than liquified natural gas. Although producing methanol and dimethyl ether from biomass results in a large reduction in total greenhouse gas emissions compared to conventional methanol and dimethyl ether production with a value of 73.96 g CO2 eq. per MJ liquified natural gas still represents a cleaner option than methanol and dimethyl ether considering the full life cycle.
Research on the Hydrogen Consumption of Fuel Cell Electric Vehicles Based on the Flowmeter and Short-cut Method
Sep 2022
Publication
Energy consumption is essential for evaluating the competitiveness of fuel cell electric vehicles. A critical step in energy consumption measurement is measuring hydrogen consumption including the mass method the P/T method and the flowmeter method. The flowmeter method has always been a research focus because of its simple operation low cost and solid real-time performance. Current research has shown the accuracy of the flowmeter method under specific conditions. However many factors in the real scenario will influence the test result such as unintended vibration environment temperature and onboard hydrogen capacity calibration. On the other hand the short-cut method is also researched to replace the run-out method to improve test efficiency. To evaluate whether the flowmeter method basing on the short-cut method can genuinely reflect the hydrogen consumption of an actual vehicle we research and test for New European Driving Cycle (NEDC) and China Light-Duty Vehicle Test Cycle (CLTC) using the same vehicle. The results show that the short-cut method can save at least 50% of the test time compared with the run-out method. The error of the short-cut method based on the flowmeter for the NEDC working condition is less than 0.1% and for the CLTC working conditions is 8.12%. After adding a throttle valve and a 4L buffer tank the error is reduced to 4.76% from 8.12%. The test results show that hydrogen consumption measurement based on the flowmeter and short-cut method should adopt corresponding solutions according to the scenarios.
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.
Cost Assessment of Alternative Fuels for Maritime Transportation in Ireland
Aug 2022
Publication
In this study we investigated the cost-effectiveness of four alternatives: Liquified Natural Gas (LNG) methanol green hydrogen and green ammonia for the case of top 20 most frequently calling ships to Irish ports in 2019 through the Net Present Value (NPV) methodology incorporating the benefits incurred through saved external carbon tax and conventional fuel costs. LNG had the highest NPV (€6166 million) followed by methanol (€1705 million) and green hydrogen (€319 million). Green ammonia utilisation (as a hydrogen carrier) looks inviable due to higher operational costs resulting from its excessive consumption (i.e. losses) during the cracking and purifying processes and its lower net calorific value. Green hydrogen remains the best option to meet future decarbonisation targets although a further reduction in its current fuel price (by 60%) or a significant increment in the proposed carbon tax rate (by 275%) will be required to improve its cost-competitiveness over LNG and methanol.
A Bird’s-Eye View on Polymer-Based Hydrogen Carriers for Mobile Applications
Oct 2022
Publication
Globally reducing CO2 emissions is an urgent priority. The hydrogen economy is a system that offers long-term solutions for a secure energy future and the CO2 crisis. From hydrogen production to consumption storing systems are the foundation of a viable hydrogen economy. Each step has been the topic of intense research for decades; however the development of a viable safe and efficient strategy for the storage of hydrogen remains the most challenging one. Storing hydrogen in polymer-based carriers can realize a more compact and much safer approach that does not require high pressure and cryogenic temperature with the potential to reach the targets determined by the United States Department of Energy. This review highlights an outline of the major polymeric material groups that are capable of storing and releasing hydrogen reversibly. According to the hydrogen storage results there is no optimal hydrogen storage system for all stationary and automotive applications so far. Additionally a comparison is made between different polymeric carriers and relevant solid-state hydrogen carriers to better understand the amount of hydrogen that can be stored and released realistically.
The Effect of Hydrogen Addition on the Pollutant Emissions of a Marine Internal Combustion Engine Genset
Sep 2022
Publication
Hydrogen as a maritime fuel is one of the solutions that will assist the shipping sector in addressing the challenges regarding decarbonization taking into consideration the targets set for 2030 and 2050. The extensive utilization of hydrogen requires massive production of green hydrogen and the development of proper infrastructure to support a sustainable supply chain. An alternative solution is based on the on-board production of hydrogen where production units are installed on-board the vessel. Along these lines the HYMAR project aims to test the utilization of a hydrogen production unit for on-board use. The article deals with the use of hydrogen as a fuel for internal combustion engines taking into consideration reports from literature and the preliminary results of the HYMAR project focusing on the environmental impact and the reduction in emissions. Experimental investigation on a marine auxiliary engine for power generation under the HYMAR project leads to promising results regarding the environmental footprint of the internal combustion engine when hydrogen is added in the fuel mix with increasing percentages.
An Overview of Water Electrolysis Technologies for Green Hydrogen Production
Oct 2022
Publication
Decarbonizing the planet is one of the major goals that countries around the world have set for 2050 to mitigate the effects of climate change. To achieve these goals green hydrogen that can be produced from the electrolysis of water is an important key solution to tackle global decarbonization. Consequently in recent years there is an increase in interest towards green hydrogen production through the electrolysis process for large-scale implementation of renewable energy based power plants and other industrial and transportation applications. The main objective of this study was to provide a comprehensive review of various green hydrogen production technologies especially on water electrolysis. In this review various water electrolysis technologies and their techno-commercial prospects including hydrogen production cost along with recent developments in electrode materials and their challenges were summarized. Further some of the most successful results also were described. Moreover this review aims to identify the gaps in water electrolysis research and development towards the techno-commercial perspective. In addition some of the commercial electrolyzer performances and their limitations also were described along with possible solutions for cost-effective hydrogen production Finally we outlined our ideas and possible solutions for driving cost-effective green hydrogen production for commercial applications. This information will provide future research directions and a road map for the development/implementation of commercially viable green hydrogen projects.
Alternative Vehicular Fuels for Environmental Decarbonization: A Critical Review of Challenges in Using Electricity, Hydrogen, and Biofuels as a Sustainable Vehicular Fuel
Jan 2023
Publication
Using vehicles powered by alternative fuels such as electricity hydrogen and biofuels have been envisioned as the ideal way to curb noxious vehicular emissions. However the availability of resources for the sustainable use of these alternative fuels the possible risks and their fate at the end of their life are frequently questioned necessitating a detailed assessment of factors influencing the use of all three alternative fuels for vehicular use. Though the vehicles powered by batteries and fuel cells are “locally” zero-emission vehicles (ZEVs) they have resource scarcity infrastructure limitations and are relatively expensive thus restricting their market penetration and consumer acceptance. Biofuels though can be used in the existing vehicles procuring the required amounts of feedstock and mitigating food-versus-fuel issues is still a challenge. Overcoming these challenges is a crucial and critical step for the sustained use of these alternative fuels as primary vehicular fuels. To accomplish this all these challenges need to be categorized and a comparative analysis among them is necessary to address them. This work can therefore serve as a ready reference for researchers and policy makers to take appropriate and informed decisions for long-term action to achieve the goals of the Paris agreement to reduce global temperature.
UK Hydrogen Strategy
Aug 2021
Publication
The UK’s first-ever Hydrogen Strategy drives forward the commitments laid out in the Prime Minister’s ambitious 10 Point Plan for a green industrial revolution by setting the foundation for how the UK government will work with industry to meet its ambition for 5GW of low carbon hydrogen production capacity by 2030 – the equivalent of replacing natural gas in powering around 3 million UK homes each year as well as powering transport and businesses particularly heavy industry.<br/>A booming UK-wide hydrogen economy could be worth £900 million and create over 9000 high-quality jobs by 2030 potentially rising to 100000 jobs and worth up to £13 billion by 2050. By 2030 hydrogen could play an important role in decarbonising polluting energy-intensive industries like chemicals oil refineries power and heavy transport like shipping HGV lorries and trains by helping these sectors move away from fossil fuels. Low-carbon hydrogen provides opportunities for UK companies and workers across our industrial heartlands.<br/>With government analysis suggesting that 20-35% of the UK’s energy consumption by 2050 could be hydrogen-based this new energy source could be critical to meet our targets of net zero emissions by 2050 and cutting emissions by 78% by 2035 – a view shared by the UK’s independent Climate Change Committee. In the UK a low-carbon hydrogen economy could deliver emissions savings equivalent to the carbon captured by 700 million trees by 2032 and is a key pillar of capitalising on cleaner energy sources as the UK moves away from fossil fuels.
Levelized Cost of Hydrogen for Refueling Stations with Solar PV and Wind in Sweden: On-grid or Off-grid?
Dec 2021
Publication
The European Union expects that hydrogen will play a vital role in future energy systems. Fuel cell electric vehicles currently present a key development path for electrification of the transport sector which requires infrastructure investments of hydrogen refueling stations preferably powered by renewables such as solar and wind energy. The economic feasibility of refueling stations depends on geographical locations. This study introduces a model to identify the key cost components of renewable hydrogen for refueling stations and simulates the performance using solar radiation wind speed and electricity price data in a selection of Swedish cities. The study demonstrates the importance of integrating the electricity grid in green hydrogen production. Wind speed is crucial in reducing the cost whereas solar radiation has less influence. In addition a combination of solar and wind brings better performance in an off-grid scenario. The most encouraging finding is the cost of 35e72 SEK/kg (3.5e7.2 V/kg) which is competitive with reported costs in other EUcountries especially since this cost excludes any government support scheme. The study provides a reference for investors and policy makers foreseeing the industrial landscape for hydrogen energy development.
The Role of Hydrogen in a Greenhouse Gas-neutral Energy Supply System in Germany
Sep 2022
Publication
Hydrogen is widely considered to play a pivotal role in successfully transforming the German energy system but the German government’s current “National Hydrogen Strategy” does not specify how hydrogen utilization production storage or distribution will be implemented. Addressing key uncertainties for the German energy system’s path to greenhouse gas-neutrality this paper examines hydrogen in different scenarios. This analysis aims to support the concretization of the German hydrogen strategy. Applying a European energy supply model with strong interactions between the conversion sector and the hydrogen system the analysis focuses on the requirements for geological hydrogen storages and their utilization over the course of a year the positioning of electrolyzers within Germany and the contributions of hydrogen transport networks to balancing supply and demand. Regarding seasonal hydrogen storages the results show that hydrogen storage facilities in the range of 42 TWhH2 to 104 TWhH2 are beneficial to shift high electricity generation volumes from onshore wind in spring and fall to winter periods with lower renewable supply and increased electricity and heat demands. In 2050 the scenario results show electrolyzer capacities between 41 GWel and 75 GWel in Germany. Electrolyzer sites were found to follow the low-cost renewable energy potential and are concentrated on the North Sea and Baltic Sea coasts with their high wind yields. With respect to a hydrogen transport infrastructure there were two robust findings: One a domestic German hydrogen transport network connecting electrolytic hydrogen production sites in northern Germany with hydrogen demand hubs in western and southern Germany is economically efficient. Two connecting Germany to a European hydrogen transport network with interconnection capacities between 18 GWH2 and 58 GWH2 is cost-efficient to meet Germany’s substantial hydrogen demand.
The Significance of Formal & Legal Factors in Selecting a Location for a Hydrogen Buffer to Stabilize the Operation of Power Distribution Networks
Oct 2022
Publication
This article presents the conceptual assumptions for the process of identifying and evaluating the formal & legal factors that impact the choice of a hydrogen buffer location to stabilize the operation of power distribution networks. The assumption for the research process was establishing a methodological framework for an in-depth analysis of legislative acts (the EU legislation and the national law) to enable identification of synthetic groups of formal & legal factors to be further analyzed using the DEMATEL method. As a result the cause-and-effect relations between the variables were examined and an in-depth analysis was carried out to investigate the level of impact of the formal & legal factors on the functioning and location of a hydrogen energy buffer.
Combined Effects of Stress and Temperature on Hydrogen Diffusion in Non-hydride Forming Alloys Applied in Gas Turbines
Jul 2022
Publication
Hydrogen plays a vital role in the utilisation of renewable energy but ingress and diffusion of hydrogen in a gas turbine can induce hydrogen embrittlement on its metallic components. This paper aims to investigate the hydrogen transport in a non-hydride forming alloy such as Alloy 690 used in gas turbines inspired by service conditions of turbine blades i.e. under the combined effects of stress and temperature. An appropriate hydrogen transport equation is formulated accounting for both stress and temperature distributions of the domain in the non-hydride forming alloy. Finite element (FE) analyses are performed to predict steady-state hydrogen distribution in lattice sites and dislocation traps of a double notched specimen under constant tensile load and various temperature fields. Results demonstrate that the lattice hydrogen concentration is very sensitive to the temperature gradients whilst the stress concentration only slightly increases local lattice hydrogen concentration. The combined effects of stress and temperature result in the highest concentration of the dislocation trapped hydrogen in low-temperature regions although the plastic strain is only at a moderate level. Our results suggest that temperature gradients and stress concentrations in turbine blades due to cooling channels and holes make the relatively low-temperature regions susceptible to hydrogen embrittlement.
Hydrogen Blending in Gas Pipeline Networks—A Review
May 2022
Publication
Replacing fossil fuels with non-carbon fuels is an important step towards reaching the ultimate goal of carbon neutrality. Instead of moving directly from the current natural gas energy systems to pure hydrogen an incremental blending of hydrogen with natural gas could provide a seamless transition and minimize disruptions in power and heating source distribution to the public. Academic institutions industry and governments globally are supporting research development and deployment of hydrogen blending projects such as HyDeploy GRHYD THyGA HyBlend and others which are all seeking to develop efficient pathways to meet the carbon reduction goal in coming decades. There is an understanding that successful commercialization of hydrogen blending requires both scientific advances and favorable techno-economic analysis. Ongoing studies are focused on understanding how the properties of methane-hydrogen mixtures such as density viscosity phase interactions and energy densities impact large-scale transportation via pipeline networks and enduse applications such as in modified engines oven burners boilers stoves and fuel cells. The advantages of hydrogen as a non-carbon energy carrier need to be balanced with safety concerns of blended gas during transport such as overpressure and leakage in pipelines. While studies on the short-term hydrogen embrittlement effect have shown essentially no degradation in the metal tensile strength of pipelines the long-term hydrogen embrittlement effect on pipelines is still the focus of research in other studies. Furthermore pressure reduction is one of the drawbacks that hydrogen blending brings to the cost dynamics of blended gas transport. Hence techno-economic models are also being developed to understand the energy transportation efficiency and to estimate the true cost of delivery of hydrogen blended natural gas as we move to decarbonize our energy systems. This review captures key large-scale efforts around the world that are designed to increase the confidence for a global transition to methane-hydrogen gas blends as a precursor to the adoption of a hydrogen economy by 2050.
Everything About Hydrogen Podcast: Producing Hydrogen with Wind Energy
Sep 2022
Publication
On this episode of Everything About Hydrogen we are speaking with David Wellard Regulatory Affairs Manager at Orsted. Orsted is a global leader in renewable energy generation projects particularly when it comes to the rapidly expanding wind energy sector. Headquartered in Denmark the company has a global reach across multiple continents and technologies. David helps lead Orsted’s policy and regulatory engagement in the United Kingdom and beyond. We are excited to have him with us to discuss how Orsted is looking at and deploying hydrogen technologies and how they expect to utilized hydrogen in a decarbonized energy future.
The podcast can be found on their website.
The podcast can be found on their website.
Two-Dimensional Photocatalysts for Energy and Environmental Applications
Jun 2022
Publication
The depletion of fossil fuels and onset of global warming dictate the achievement of efficient technologies for clean and renewable energy sources. The conversion of solar energy into chemical energy plays a vital role both in energy production and environmental protection. A photocatalytic approach for H2 production and CO2 reduction has been identified as a promising alternative for clean energy production and CO2 conversion. In this process the most critical parameter that controls efficiency is the development of a photocatalyst. Two-dimensional nanomaterials have gained considerable attention due to the unique properties that arise from their morphology. In this paper examples on the development of different 2D structures as photocatalysts in H2 production and CO2 reduction are discussed and a perspective on the challenges and required improvements is given.
The Influence of the First Filling Period Length and Reservoir Level Depth on the Operation of Underground Hydrogen Storage in a Deep Aquifer
Sep 2022
Publication
Underground storage is a method of storing large amounts of renewable energy that can be converted into hydrogen. One of the fundamental problems associated with this process concerns determining the timing and amount of injected gas in the first filling period for the operation of an underground storage facility. Ascertaining the hydrogen flow rate is essential to ensure that the capillary and fracturing pressures are not exceeded. The value of the flow rate was assessed by modelling the injection of hydrogen into a deep aquifer. The best initial H2 injection period was found to be five months. The volume of the cushion gas and the total storage capacity expanded with the extension of the first filling period length. The working capacity grew as the depth increased reaching maximum values at depths of approximately 1200e1400 m. This depth was considered optimal for storing hydrogen in the analysed structure.
Recent Progress in Mixed-Matrix Membranes for Hydrogen Separation
Aug 2021
Publication
Membrane separation is a compelling technology for hydrogen separation. Among the different types of membranes used to date the mixed-matrix membranes (MMMs) are one of the most widely used approaches for enhancing separation performances and surpassing the Robeson upper bound limits for polymeric membranes. In this review we focus on the recent progress in MMMs for hydrogen separation. The discussion first starts with a background introduction of the current hydrogen generation technologies followed by a comparison between the membrane technology and other hydrogen purification technologies. Thereafter state-of-the-art MMMs comprising emerging filler materials that include zeolites metal-organic frameworks covalent organic frameworks and graphene-based materials are highlighted. The binary filler strategy which uses two filler materials to create synergistic enhancements in MMMs is also described. A critical evaluation on the performances of the MMMs is then considered in context before we conclude with our perspectives on how MMMs for hydrogen separation can advance moving forward.
Integrated Energy System Powered a Building in Sharjah Emirates in the United Arab Emirates
Jan 2023
Publication
In this study a green hydrogen system was studied to provide electricity for an office building in the Sharjah emirate in the United Arab Emirates. Using a solar PV a fuel cell a diesel generator and battery energy storage; a hybrid green hydrogen energy system was compared to a standard hybrid system (Solar PV a diesel generator and battery energy storage). The results show that both systems adequately provided the power needed for the load of the office building. The cost of the energy for both the basic and green hydrogen energy systems was 0.305 USD/kWh and 0.313 USD/kWh respectively. The cost of the energy for both systems is very similar even though the capital cost of the green hydrogen energy system was the highest value; however the replacement and operational costs of the basic system were higher in comparison to the green hydrogen energy system. Moreover the impact of the basic system in terms of the carbon footprint was more significant when compared with the green hydrogen system. The reduction in carbon dioxide was a 4.6 ratio when compared with the basic system.
Sizing Hydrogen Energy Storage in Consideration of Demand Response in Highly Renewable Generation Power Systems
May 2018
Publication
From an environment perspective the increased penetration of wind and solar generation in power systems is remarkable. However as the intermittent renewable generation briskly grows electrical grids are experiencing significant discrepancies between supply and demand as a result of limited system flexibility. This paper investigates the optimal sizing and control of the hydrogen energy storage system for increased utilization of renewable generation. Using a Finnish case study a mathematical model is presented to investigate the optimal storage capacity in a renewable power system. In addition the impact of demand response for domestic storage space heating in terms of the optimal sizing of energy storage is discussed. Finally sensitivity analyses are conducted to observe the impact of a small share of controllable baseload production as well as the oversizing of renewable generation in terms of required hydrogen storage size.
Development and Operation Modes of Hydrogen Fuel Cell Generation System for Remote Consumers’ Power Supply
Aug 2021
Publication
At the present stage of electric power industry development special attention is being paid to the development and research of new efficient energy sources. The use of hydrogen fuel cells is promising for remote autonomous power supply systems. The authors of the paper have developed the structure and determined the optimal composition of a hybrid generation system based on hydrogen fuel cells and battery storage and have conducted studies of its operating modes and for remote consumers’ power supply efficiency. A simulation of the electromagnetic processes was carried out to check the operability of the proposed hybrid generation system structure. The simulation results confirmed the operability of the structure under consideration the calculation of its parameters reliability and the high quality of the output voltage. The electricity cost of a hybrid generation system was estimated according to the LCOE (levelized cost of energy) indicator its value being 1.17 USD/kWh. The factors influencing the electricity cost of a hydrogen generation system have been determined and ways for reducing its cost identified.
Green Hydrogen and Energy Transition: Current State and Prospects in Portugal
Jan 2023
Publication
Hydrogen is a promising commodity a renewable secondary energy source and feedstock alike to meet greenhouse gas emissions targets and promote economic decarbonization. A common goal pursued by many countries the hydrogen economy receives a blending of public and private capital. After European Green Deal state members created national policies focused on green hydrogen. This paper presents a study of energy transition considering green hydrogen production to identify Portugal’s current state and prospects. The analysis uses energy generation data hydrogen production aspects CO2 emissions indicators and based costs. A comprehensive simulation estimates the total production of green hydrogen related to the ratio of renewable generation in two different scenarios. Then a comparison between EGP goals and Portugal’s transport and energy generation prospects is made. Portugal has an essential renewable energy matrix that supports green hydrogen production and allows for meeting European green hydrogen 2030–2050 goals. Results suggest that promoting the conversion of buses and trucks into H2-based fuel is better for CO2 reduction. On the other hand given energy security thermoelectric plants fueled by H2 are the best option. The aggressive scenario implies at least 5% more costs than the moderate scenario considering economic aspects.
Experimental Characterization and Energy Performance Assessment of a Sorption-Enhanced Steam–Methane Reforming System
Aug 2021
Publication
The production of blue hydrogen through sorption-enhanced processes has emerged as a suitable option to reduce greenhouse gas emissions. Sorption-enhanced steam–methane reforming (SESMR) is a process intensification of highly endothermic steam–methane reforming (SMR) ensured by in situ carbon capture through a solid sorbent making hydrogen production efficient and more environmentally sustainable. In this study a comprehensive energy model of SESMR was developed to carry out a detailed energy characterization of the process with the aim of filling a current knowledge gap in the literature. The model was applied to a bench-scale multicycle SESMR/sorbent regeneration test to provide an energy insight into the process. Besides the experimental advantages of higher hydrogen concentration (90 mol% dry basis 70 mol% wet basis) and performance of CO2 capture the developed energy model demonstrated that SESMR allows for substantially complete energy self-sufficiency through the process. In comparison to SMR with the same process conditions (650 ◦C 1 atm) performed in the same experimental rig SESMR improved the energy efficiency by about 10% further reducing energy needs.
Modelling and Simulation of a Hydrogen-Based Hybrid Energy Storage System with a Switching Algorithm
Oct 2022
Publication
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.
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