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A Simple and Low-cost Integrative Sensor System for Methane and Hydrogen Measurement
Sep 2020
Publication
Energy production by methanization or gasification of biomass is dependant on the chemical composition of the gas generated. The resistive sensors based on semiconductor metal oxides like the MQ series sensors are inexpensive and frequently used in gas detection. These sensors initially dedicated to detecting gas leaks in safety systems have relatively small measurement ranges (i.e. limited to concentrations below 10000 ppm). It is therefore necessary to find solutions to adapt these categories of sensors for gas measurements in the energy sector where the gas concentration is much more significant. In this article we propose a protocol using an adaptable capsule for MQ-4 and MQ-8 sensors to measure high concentrations of CH4 and H2 respectively. The technique consists of diluting the gas to be studied in a known volume of air. Three methods are proposed and compared regarding the linearity and the repeatability of the measurements. The first method was done in an airtight enclosed chamber the second method consists of directly injecting the gas on the sensor placed in an open environment and the final method was accomplished by direct injection of the gas on the sensor placed in a partially closed capsule. Comparisons show that the first technique provides the best repeatability with a maximum standard deviation of 13.88% for CH4 measurement and 5.1% for H2. However its linearity is weak (i.e. R2 ¼ 0.8637 for CH4 and R2 ¼ 0.5756 for H2). The second technique has better linearity but bad repeatability. The third technique presents the best results with R2 values of 0.9973 for the CH4 measurement and 0.9472 for H2. The use of the partially closed capsule resulted in an acceptable linear response of the sensors by up to 20% concentration of CH4 and until 13.33% concentration of H2 in the studied gas. The use of this simple and low-cost technique facilitates the characterization of combustible gases in isolated areas. It allows local operators of biomass valorization systems to control and improve their installations while avoiding the high costs of conventional measurement devices. This study hence contributes to the development of rural electrification projects in remote areas.
Combustion Characteristics of Hydrogen Direct Injection in a Helium–oxygen Compression Ignition Engine
Jul 2022
Publication
The ignition of hydrogen in compression ignition (CI) engines by adding noble gas as a working gas can yield excellent thermal efficiency due to its high specific heat ratio. This paper emphasizes the potential of helium–oxygen atmosphere for hydrogen combustion in CI engines and provides data on the engine configuration. A simulation was conducted using Converge CFD software based on the Yanmar NF19SK engine parameters. Helium–oxygen atmosphere compression show promising hydrogen autoignition results with the in-cylinder temperature was significantly higher than that of air during the compression stroke. In a compression ignition engine with a low compression ratio (CR) and intake temperature helium–oxygen atmosphere is recognized as the best working gas for hydrogen combustion. The ambient intake temperature was sufficient for hydrogen ignition in low CR with minimal heat flux effect. The best intake temperature for optimum engine efficiency in a low CR engine is 340 K and the engine compression ratio for optimum engine efficiency at ambient intake temperature is CR12 with an acceptable cylinder wall heat flux value. The helium–oxygen atmosphere as a working gas for hydrogen combustion in CI engines should be consider based on the parameter provided for clean energy transition with higher thermal efficiency.
Ammonia as a Carrier for Hydrogen Production by using Lanthanum Based Perovskites
Sep 2021
Publication
LaNiO3 and LaCoO3 perovskites synthesized by self-combustion were characterised and studied in the ammonia decomposition reaction for obtaining hydrogen. Both the fuel to metal nitrates molar ratio and calcination temperature were found to be crucial to synthesize perovskites by self-combustion. Moreover generating non-precursor species during synthesis and small metal size were two factors which significantly influenced catalytic activity. Hence with a citric acid to metal nitrates molar ratio equal to one a LaNiO3 perovskite was obtained with suitable physicochemical properties (specific surface area lower impurities and basicity). In addition a lower calcination temperature (650 ◦C) resulted in small and well-dispersed Ni0 crystallite size after reduction which in turn promoted the catalytic transformation of ammonia into hydrogen. For cobalt perovskites calcination temperature below 900 ◦C did not have a significant influence on the size of the metallic cobalt crystallite size. The nickel and cobalt perovskite-derived catalysts calcined at 650 ◦C and 750 ◦C respectively yielded excellent H2 production from ammonia decomposition. In particular at 450 ◦C almost 100% of the ammonia was converted over the LaNiO3 under study. Furthermore these materials displayed admirable performance and stability after one day of reaction.
Current Legislative Framework for Green Hydrogen Production by Electrolysis Plants in Germany
Mar 2022
Publication
(1) The German energy system transformation towards an entirely renewable supply is expected to incorporate the extensive use of green hydrogen. This carbon-free fuel allows the decarbonization of end-use sectors such as industrial high-temperature processes or heavy-duty transport that remain challenging to be covered by green electricity only. However it remains unclear whether the current legislative framework supports green hydrogen production or is an obstacle to its rollout. (2) This work analyzes the relevant laws and ordinances regarding their implications on potential hydrogen production plant operators. (3) Due to unbundling-related constraints potential operators from the group of electricity transport system and distribution system operators face lacking permission to operate production plants. Moreover ownership remains forbidden for them. The same applies to natural gas transport system operators. The case is less clear for natural gas distribution system operators where explicit regulation is missing. (4) It is finally analyzed if the production of green hydrogen is currently supported in competition with fossil hydrogen production not only by the legal framework but also by the National Hydrogen Strategy and the Amendment of the Renewable Energies Act. It can be concluded that in recent amendments of German energy legislation regulatory support for green hydrogen in Germany was found. The latest legislation has clarified crucial points concerning the ownership and operation of electrolyzers and the treatment of green hydrogen as a renewable energy carrier.
Time-phased Geospatial Siting Analysis for Renewable Hydrogen Production Facilities under a Billion-kilogram-scale Build-out using California as an Example
Jun 2022
Publication
For renewable hydrogen to be a significant part of the future decarbonized energy and transportation sectors a rapid and massive build-out of hydrogen production facilities will be needed. This paper describes a geospatial modeling approach to identifying the optimal locations for renewable hydrogen fuel production throughout the state of California based on least-cost generation and transport. This is accomplished by (1) estimating and projecting California renewable hydrogen demand scenarios through the year 2050 (2) identifying feedstock locations (3) excluding areas not suitable for development and (4) selecting optimal site locations using commercial geospatial modeling software. The findings indicate that there is a need for hundreds of new renewable hydrogen production facilities in the decades preceding the year 2050. In selecting sites for development feedstock availability by technology type is the driving factor."
Hydrogen Storage: Recent Improvements and Industrial Perspectives
Sep 2021
Publication
Efficient storage of hydrogen is crucial for the success of hydrogen energy markets. Hydrogen can be stored either as a compressed gas a refrigerated liquefied gas a cryo-compressed gas or in hydrides. This paper gives an overview of compressed hydrogen storage technologies focusing on high pressure storage tanks in metal and in composite materials. It details specific issues and constraints related to the materials and structure behavior in hydrogen and conditions representative of hydrogen energy uses. This paper is an update of the 2019 version that was presented in Australia. It especially covers recent progress made regarding regulations codes and standards for the design manufacturing periodic inspection and plastic materials’ evaluation of compressed hydrogen storage.
Effect of Flow Speed on Ignition Characteristics of Hydrogen/air Mixtures
Sep 2021
Publication
A fuel cell vehicle has a purging system for exhausting contaminated hydrogen gas. Notwithstanding the allowable hydrogen emissions levels in the purging system are regulated by the GTR a further research on the safety requirement of emissions concentrations is therefore needed for the vehicle design into a more rational system. In the present study the effects of flow speed concentration humidity on ignition characteristics of hydrogen/air mixtures were experimentally investigated. The results demonstrate that the value of Lower Flammable Limit increased with an increase in the velocity of hydrogen/air mixtures and slightly increased with a decrease in oxygen concentration.
A Review on Hydrogen-Based Hybrid Microgrid System: Topologies for Hydrogen Energy Storage, Integration, and Energy Management with Solar and Wind Energy
Oct 2022
Publication
Hydrogen is acknowledged as a potential and appealing energy carrier for decarbonizing the sectors that contribute to global warming such as power generation industries and transportation. Many people are interested in employing low-carbon sources of energy to produce hydrogen by using water electrolysis. Additionally the intermittency of renewable energy supplies such as wind and solar makes electricity generation less predictable potentially leading to power network incompatibilities. Hence hydrogen generation and storage can offer a solution by enhancing system flexibility. Hydrogen saved as compressed gas could be turned back into energy or utilized as a feedstock for manufacturing building heating and automobile fuel. This work identified many hydrogen production strategies storage methods and energy management strategies in the hybrid microgrid (HMG). This paper discusses a case study of a HMG system that uses hydrogen as one of the main energy sources together with a solar panel and wind turbine (WT). The bidirectional AC-DC converter (BAC) is designed for HMGs to maintain power and voltage balance between the DC and AC grids. This study offers a control approach based on an analysis of the BAC’s main circuit that not only accomplishes the function of bidirectional power conversion but also facilitates smooth renewable energy integration. While implementing the hydrogen-based HMG the developed control technique reduces the reactive power in linear and non-linear (NL) loads by 90.3% and 89.4%.
Multi-model Assessment of Heat Decarbonisation Options in the UK Using Electricity and Hydrogen
May 2022
Publication
Delivering low-carbon heat will require the substitution of natural gas with low-carbon alternatives such as electricity and hydrogen. The objective of this paper is to develop a method to soft-link two advanced investment-optimising energy system models RTN (Resource-Technology Network) and WeSIM (Whole-electricity System Investment Model) in order to assess cost-efficient heat decarbonisation pathways for the UK while utilising the respective strengths of the two models. The linking procedure included passing on hourly electricity prices from WeSIM as input to RTN and returning capacities and locations of hydrogen generation and shares of electricity and hydrogen in heat supply from RTN to WeSIM. The outputs demonstrate that soft-linking can improve the quality of the solution while providing useful insights into the cost-efficient pathways for zero-carbon heating. Quantitative results point to the cost-effectiveness of using a mix of electricity and hydrogen technologies for delivering zero-carbon heat also demonstrating a high level of interaction between electricity and hydrogen infrastructure in a zero-carbon system. Hydrogen from gas reforming with carbon capture and storage can play a significant role in the medium term while remaining a cost-efficient option for supplying peak heat demand in the longer term with the bulk of heat demand being supplied by electric heat pumps.
Wind Resource Assessment and Techno-economic Analysis of Wind Energy and Green Hydrogen Production in the Republic of Djibouti
Jul 2022
Publication
The ever increasing energy demand of the Republic of Djibouti leads to the diversification of energy sources. While a few studies have explored the prospects of green hydrogen production from wind energy in developing countries and particularly in Africa the economic risk analysis of wind power production for electricity generation and green hydrogen production has not been assessed for African countries. This study evaluates for the first time the potential of wind energy for electricity and green hydrogen production in the Republic of Djibouti. In this study wind speed characteristics were analyzed using wind data measured at five meteorological stations from 2015 to 2019. The technoeconomic analysis of five wind farms with a total capacity of 450 MW is performed. Levelized cost of energy production (LCOE) levelized cost of green hydrogen production (LCOH) sensitivity analysis Monte Carlo simulation and economic performance indicators are presented. Results reveal that the annual wind speed varies between 5.52 m/s and 9.01 m/s for the five sites. ERA5 wind reanalysis indicates that the seasonal variability of wind is stable between different years. The proposed wind farms estimate 1739 GWh per year of electrical energy with LCOE ranging from 6.94 to 13.30 US cents/kWh which is less than the locale electricity tariff. The production cost of green hydrogen was competitive with LCOH ranging from 1.79 to 3.38 US $/kg H2. The sensitivity analysis shows that the most relevant parameters in the economic analysis are the initial investment cost the interest rate and the factor capacity.
Everything About Hydrogen Podcast: Hydrogen 101
Aug 2019
Publication
A 10-minute tour of hydrogen industry technology and terminology for those who are new to the sector or who would simply like a quick review of the basics behind this burgeoning energy source.
Podcast can be found on their website
Podcast can be found on their website
Utilization of Excess Water Accumulation for Green Hydrogen Production in a Run-ofTiver Hydropower Plant
Jun 2022
Publication
This paper discusses the potential for green-hydrogen production in a run-of-river 9 hydropower plant. This particular hydropower plant has no significant water accumulation but 10 there is the potential for limited hydrogen production due to a mismatch between the daily 11 predefined electricity production (known as the timetable) and the actual water inflows. The 12 timetable for the hydropower plant is prepared by the operator of the electro-energetic system 13 based on a model of the available production capacities forecasted consumption water 14 accumulation state of the river flows weather forecasts and the system operator’s strategy. The 15 uncertainty in the model’s input parameters is reflected in the output timetable for the 16 hydropower plant and for this reason a small reserve of water for potential exploitation is 17 envisaged. By using real data for the timetable and the water inflow we estimate the excess 18 hydropower that can be used for hydrogen cogeneration. Since the primary task of the 19 hydropower plant is to produce electricity according to the timetable the production of 20 hydrogen is only possible to a limited extent. Therefore we present a control algorithm that 21 regulates the amount of hydrogen production while considering the predefined timetable and 22 the real water accumulation. The second part of the paper deals with the economic viability of 23 hydrogen cogeneration in the case-study run-of-river hydropower plant and discusses the 24 possibility of using it for local public transport.
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.
Catalyst Distribution Optimization Scheme for Effective Green Hydrogen Production from Biogas Reforming
Sep 2021
Publication
Green hydrogen technology has recently gained in popularity due to the current economic and ecological trends that aim to remove the fossil fuels share in the energy mix. Among various alternatives biogas reforming is an attractive choice for hydrogen production. To meet the authorities’ requirements reforming biogas-enriched natural gas and sole biogas is tempting. Highly effective process conditions of biogas reforming are yet to be designed. The current state of the art lacks proper optimization of the process conditions. The optimization should aim to allow for maximization of the process effectiveness and limitation of the phenomena having an adverse influence on the process itself. One of the issues that should be addressed in optimization is the uniformity of temperature inside a reactor. Here we show an optimization design study that aims to unify temperature distribution by novel arrangements of catalysts segments in the model biogas reforming reactor. The acquired numerical results confirm the possibility of the enhancement of reaction effectiveness coming from improving the thermal conditions. The used amount of catalytic material is remarkably reduced as a side effect of the presented optimization. To ensure an unhindered perception of the reaction improvement the authors proposed a ratio of the hydrogen output and the amount of used catalyst as a measure.
Promising Technology Analysis and Patent Roadmap Development in the Hydrogen Supply Chain
Oct 2022
Publication
Hydrogen energy one of the energy sources of the future represents a substantial issue which affects the industries and national technologies that will develop in the future. In order to utilize hydrogen energy a hydrogen supply chain is required so that hydrogen can be processed and transported to vehicles. It is helpful for technology and policy development to analyze technologies necessary to charge the hydrogen energy generated into vehicles through the supply chain to discover technologies with high potential for future development. The purpose of this paper is to identify promising technologies required in storing transporting and charging vehicles generated by the hydrogen fuel supply chain. Afterward the promising technologies identified are expected to help researchers set a direction in researching technologies and developing related policies. Therefore we provide technology information that can be used promisingly in the future so that researchers in the related field can utilize it effectively. In this paper data analysis is performed using related patents and research papers for technical analysis. Promising technologies that will be the core of the hydrogen fuel supply chain in the future were identified using the published patents and research paper database (DB) in Korea the United States Europe China and Japan. A text mining technique was applied to preprocess data and then a generic topographic map (GTM) analysis discovered promising technologies. Then a technology roadmap was identified by analyzing the promising technology derived from patents and research papers in parallel. In this study through the analysis of patents and research papers related to the hydrogen supply chain the development status of hydrogen storage/transport/charging technology was analyzed and promising technologies with high potential for future development were found. The technology roadmap derived from the analysis can help researchers in the field of hydrogen research establish policies and research technologies.
Economic Dispatch Model of Nuclear High-Temperature Reactor with Hydrogen Cogeneration in Electricity Market
Dec 2021
Publication
Hydrogen produced without carbon emissions could be a useful fuel as nations look to decarbonize their electricity transport and industry sectors. Using the iodine–sulfur (IS) cycle coupled with a nuclear heat source is one method for producing hydrogen without the use of fossil fuels. An economic dispatch model was developed for a nuclear-driven IS system to determine hydrogen sale prices that would make such a system profitable. The system studied is the HTTR GT/H2 a design for power and hydrogen cogeneration at the Japan Atomic Energy Agency’s High Temperature Engineering Test Reactor. This study focuses on the development of the economic model and the role that input data plays in the final calculated values. Using a historical price duration curve shows that the levelized cost of hydrogen (LCOH) or breakeven sale price of hydrogen would need to be 98.1 JPY/m3 or greater. Synthetic time histories were also used and found the LCOH to be 67.5 JPY/m3 . The price duration input was found to have a significant effect on the LCOH. As such great care should be used in these economic dispatch analyses to select reasonable input assumptions.
Green Hydrogen Production from Raw Biogas: A Techno-Economic Investigation of Conventional Processes Using Pressure Swing Adsorption Unit
Feb 2018
Publication
This paper discusses the techno-economic assessment of hydrogen production from biogas with conventional systems. The work is part of the European project BIONICO whose purpose is to develop and test a membrane reactor (MR) for hydrogen production from biogas. Within the BIONICO project steam reforming (SR) and autothermal reforming (ATR) have been identified as well-known technologies for hydrogen production from biogas. Two biogases were examined: one produced by landfill and the other one by anaerobic digester. The purification unit required in the conventional plants has been studied and modeled in detail using Aspen Adsorption. A pressure swing adsorption system (PSA) with two and four beds and a vacuum PSA (VPSA) made of four beds are compared. VPSA operates at sub-atmospheric pressure thus increasing the recovery: results of the simulations show that the performances strongly depend on the design choices and on the gas feeding the purification unit. The best purity and recovery values were obtained with the VPSA system which achieves a recovery between 50% and 60% at a vacuum pressure of 0.1 bar and a hydrogen purity of 99.999%. The SR and ATR plants were designed in Aspen Plus integrating the studied VPSA model and analyzing the behavior of the systems at the variation of the pressure and the type of input biogas. The SR system achieves a maximum efficiency calculated on the LHV of 52% at 12 bar while the ATR of 28% at 18 bar. The economic analysis determined a hydrogen production cost of around 5 €/kg of hydrogen for the SR case.
Review of the Hydrogen Permeability of the Liner Material of Type IV On-Board Hydrogen Storage Tank
Aug 2021
Publication
The hydrogen storage tank is a key parameter of the hydrogen storage system in hydrogen fuel cell vehicles (HFCVs) as its safety determines the commercialization of HFCVs. Compared with other types the type IV hydrogen storage tank which consists of a polymer liner has the advantages of low cost lightweight and low storage energy consumption but meanwhile higher hydrogen permeability. A detailed review of the existing research on hydrogen permeability of the liner material of type IV hydrogen storage tanks can improve the understanding of the hydrogen permeation mechanism and provide references for following-up researchers and research on the safety of HFCVs. The process of hydrogen permeation and test methods are firstly discussed in detail. This paper then analyzes the factors that affect the process of hydrogen permeation and the barrier mechanism of the liner material and summarizes the prediction models of gas permeation. In addition to the above analysis and comments future research on the permeability of the liner material of the type IV hydrogen storage tank is prospected.
Fire Spread Scenarios Involving Hydrogen Vehicles
Sep 2021
Publication
Fire spread between vehicles provides a potential risk in parking areas with many vehicles. Several reported very large fires caused the loss of a great number of vehicles. These fires seem to be in contradiction to the European design rules for car parks assuming only a very limited number of vehicles may be on fire at the same time. The fire spread in a car park environment is dependent on many factors of both the vehicles and the structure e.g. the latter has an impact on the rate of fire spread due to reradiation of the vehicles heat release. Therefore a CFD model is established to develop a tool to assess vehicles and better understand fire scenarios in different structures. Further the model enables testing of building design to prevent and mitigate such fires scenarios involving hydrogen vehicles. In this study a real layout of a car park is modelled to investigate the effects of hydrogen emergency releases that have used different TPRD diameters. The results provide insight into the behaviour of hydrogen cars and the release pattern of the TPRD's as well as the temperature development of the concrete ceiling and concrete beams above the cars. It shows that the TPRD diameter has a little effect on the TPRD activation time of the no.1 vehicle when the amount of H2 in the tank is the same. For the surface temperature of the ceiling and beam the peak temperature for a 1mm diameter TPRD release is found highest.
“Bigger than Government”: Exploring the Social Construction and Contestation of Net-zero Industrial Megaprojects in England
Jan 2023
Publication
Industry is frequently framed as hard-to-decarbonize given its diversity of requirements technologies and supply chains many of which are unique to particular sectors. Net zero commitments since 2019 have begun to challenge the carbon intensity of these various industries but progress has been slow globally. Against this backdrop the United Kingdom has emerged as a leader in industrial decarbonization efforts. Their approach is based on industrial clusters which cut across engineering spatial and socio-political dimensions. Two of the largest of these clusters in England in terms of industrial emissions are the Humber and Merseyside. In this paper drawn from a rich mixed methods original dataset involving expert interviews (N = 46 respondents) site visits (N = 20) a review of project documents and the academic literature we explore ongoing efforts to decarbonize both the Humber and Merseyside through the lens of spatially expansive and technically complex megaprojects. Both have aggressive implementation plans in place for the deployment of net-zero infrastructure with Zero Carbon Humber seeking billions in investment to build the country’s first large-scale bioenergy with carbon capture and storage (BECCS) plant alongside a carbon transport network and hydrogen production infrastructure and HyNet seeking billions in investment to build green and blue hydrogen facilities along with a carbon storage network near Manchester and Liverpool. We draw from the social construction of technology (SCOT) literature to examine the relevant social groups interpretive flexibility and patterns of closure associated with Zero Carbon Humber and HyNet. We connect our findings to eight interpretive frames surrounding the collective projects and make connections to problems contestation and closure.
Solar Fuel Processing: Comparative Mini-review on Research, Technology Development, and Scaling
Oct 2022
Publication
Solar energy provides an unprecedented potential as a renewable and sustainable energy resource and will substantially reshape our future energy economy. It is not only useful in producing electricity but also (hightemperature) heat and fuel both required for non-electrifiable energy services. Fuels are particularly valuable as they are energy dense and storable and they can also act as a feedstock for the chemical industry. Technical pathways for the processing of solar fuels include thermal pathways (e.g. solar thermochemistry) photo pathways (e.g. photoelectrochemistry) and combinations thereof. A review of theoretical limits indicates that all technical solar fuel processing pathways have the potential for competitive solar-to-fuel efficiencies (>10 %) but require very different operating conditions (e.g. temperature levels or oxygen partial pressures) making them complementary and highly versatile for process integration. Progress in photoelectrochemical devices and solar thermochemical reactors over the last 50 + years are summarized showing encouraging trends in terms of performance technological viability and scaling.
Interaction of Hydrogen Infrastructures with other Sector Coupling Options Towards a Zero-emission Energy System in Germany
Aug 2021
Publication
The flexible coupling of sectors in the energy system for example via battery electric vehicles electric heating or electric fuel production can contribute significantly to the integration of variable renewable electricity generation. For the implementation of the energy system transformation however there are numerous options for the design of sector coupling each of which is accompanied by different infrastructure requirements. This paper presents the extension of the REMix energy system modelling framework to include the gas sector and its application for investigating the cost-optimal design of sector coupling in Germany's energy system. Considering an integrated optimisation of all relevant technologies in their capacities and hourly use a path to a climate-neutral system in 2050 is analysed. We show that the different options for flexible sector coupling are all needed and perform different functions. Even though flexible electrolytic production of hydrogen takes on a very dominant role in 2050 it does not displace other technologies. Hydrogen also plays a central role in the seasonal balancing of generation and demand. Thus large-scale underground storage is part of the optimal system in addition to a hydrogen transport network. These results provide valuable guidance for the implementation of the energy system transformation in Germany.
Experimental Study on Flame Characteristics of Cryogenic Hydrogen Jet Fire
Sep 2021
Publication
In this work cryogenic hydrogen fires at fixed pressures and various initial temperatures were investigated experimentally. Flame length width heat fluxes and temperatures in down-stream regions were measured for the scenarios with 1.6-3 mm jet nozzle 106 to 273 K 2-5 barabs. The results show that the flame size is related to not only the jet nozzle diameter but also the release pressure and initial temperature. The correlations of normalized flame length and width are proposed with the stagnation pressure and the ratio of ambient and stagnation temperatures. Under constant pressure the flame size total radiative power and radiation fraction increase with the decrease of temperature due to lower choked flow velocity and higher density of cryogenic hydrogen. The correlation of radiation fraction proposed by Molina et al. at room temperature is not suitable to predict the cryogenic hydrogen jet fires. Based on piecewise polynomial law
The Role of Natural Gas and its Infrastructure in Mitigating Greenhouse Gas Emissions, Improving Regional Air Quality, and Renewable Resource Integration
Nov 2017
Publication
The pursuit of future energy systems that can meet electricity demands while supporting the attainment of societal environment goals including mitigating climate change and reducing pollution in the air has led to questions regarding the viability of continued use of natural gas. Natural gas use particularly for electricity generation has increased in recent years due to enhanced resource availability from non-traditional reserves and pressure to reduce greenhouse gasses (GHG) from higher-emitting sources including coal generation. While lower than coal emissions current natural gas power generation strategies primarily utilize combustion with higher emissions of GHG and criteria pollutants than other low-carbon generation options including renewable resources. Furthermore emissions from life cycle stages of natural gas production and distribution can have additional detrimental GHG and air quality (AQ) impacts. On the other hand natural gas power generation can play an important role in supporting renewable resource integration by (1) providing essential load balancing services and (2) supporting the use of gaseous renewable fuels through the existing infrastructure of the natural gas system. Additionally advanced technologies and strategies including fuel cells and combined cooling heating and power (CCHP) systems can facilitate natural gas generation with low emissions and high efficiencies. Thus the role of natural gas generation in the context of GHG mitigation and AQ improvement is complex and multi-faceted requiring consideration of more than simple quantification of total or net emissions. If appropriately constructed and managed natural gas generation could support and advance sustainable and renewable energy. In this paper a review of the literature regarding emissions from natural gas with a focus on power generation is conducted and discussed in the context of GHG and AQ impacts. In addition a pathway forward is proposed for natural gas generation and infrastructure to maximize environmental benefits and support renewable resources in the attainment of emission reductions.
Parametric Study and Electrocatalyst of Polymer Electrolyte Membrane (PEM) Electrolysis Performance
Jan 2023
Publication
An investigation was conducted to determine the effects of operating parameters for various electrode types on hydrogen gas production through electrolysis as well as to evaluate the efficiency of the polymer electrolyte membrane (PEM) electrolyzer. Deionized (DI) water was fed to a single-cell PEM electrolyzer with an active area of 36 cm2 . Parameters such as power supply (50–500 mA/cm2 ) feed water flow rate (0.5–5 mL/min) water temperature (25−80 ◦C) and type of anode electrocatalyst (0.5 mg/cm2 PtC [60%] 1.5 mg/cm2 IrRuOx with 1.5 mg/cm2 PtB 3.0 mg/cm2 IrRuOx and 3.0 mg/cm2 PtB) were varied. The effects of these parameter changes were then analyzed in terms of the polarization curve hydrogen flowrate power consumption voltaic efficiency and energy efficiency. The best electrolysis performance was observed at a DI water feed flowrate of 2 mL/min and a cell temperature of 70 ◦C using a membrane electrode assembly that has a 3.0 mg/cm2 IrRuOx catalyst at the anode side. This improved performance of the PEM electrolyzer is due to the reduction in activation as well as ohmic losses. Furthermore the energy consumption was optimal when the current density was about 200 mA/cm2 with voltaic and energy efficiencies of 85% and 67.5% respectively. This result indicates low electrical energy consumption which can lower the operating cost and increase the performance of PEM electrolyzers. Therefore the optimal operating parameters are crucial to ensure the ideal performance and durability of the PEM electrolyzer as well as lower its operating costs.
Performance of Common Rail Direct Injection (CRDi) Engine Using Ceiba Pentandra Biodiesel and Hydrogen Fuel Combination
Nov 2021
Publication
An existing diesel engine was fitted with a common rail direct injection (CRDi) facility to inject fuel at higher pressure in CRDi mode. In the current work rotating blades were incorporated in the piston cavity to enhance turbulence. Pilot fuels used are diesel and biodiesel of Ceiba pentandra oil (BCPO) with hydrogen supply during the suction stroke. Performance evaluation and emission tests for CRDi mode were carried out under different loading conditions. In the first part of the work maximum possible hydrogen substitution without knocking was reported at an injection timing of 15◦ before top dead center (bTDC). In the second part of the work fuel injection pressure (IP) was varied with maximum hydrogen fuel substitution. Then in the third part of the work exhaust gas recirculation (EGR) was varied to study the nitrogen oxides (NOx) generated. At 900 bar HC emissions in the CRDi engine were reduced by 18.5% and CO emissions were reduced by 17% relative to the CI mode. NOx emissions from the CRDi engine were decreased by 28% relative to the CI engine mode. At 20% EGR lowered the BTE by 14.2% and reduced hydrocarbons nitrogen oxide and carbon monoxide by 6.3% 30.5% and 9% respectively compared to the CI mode of operation.
Everything About Hydrogen Podcast: Global Energy Majors in the Hydrogen Space
Jul 2022
Publication
On today’s episode of Everything About Hydrogen we are speaking with Paul Bogers Vice President for Hydrogen at Shell. As a company Shell needs no introduction but the company’s work and investments in the hydrogen space make it a global leader in the energy transition especially when it comes to the hydrogen component. Paul is amongst the executives at Shell that are working to bring their hydrogen vision to fruition and it is great to have him with us on the show today.
The podcast can be found on their website
The podcast can be found on their website
The Potential Role of Ammonia as Marine Fuel—Based on Energy Systems Modeling and Multi-Criteria Decision Analysis
Apr 2020
Publication
To reduce the climate impact of shipping the introduction of alternative fuels is required. There is a range of different marine fuel options but ammonia a potential zero carbon fuel has recently received a lot of attention. The purpose of this paper is to assess the prospects for ammonia as a future fuel for the shipping sector in relation to other marine fuels. The assessment is based on a synthesis of knowledge in combination with: (i) energy systems modeling including the cost-effectiveness of ammonia as marine fuel in relation to other fuels for reaching global climate targets; and (ii) a multi-criteria decision analysis (MCDA) approach ranking marine fuel options while considering estimated fuel performance and the importance of criteria based on maritime stakeholder preferences. In the long-term and to reach global GHG reduction the energy systems modeled indicate that the use of hydrogen represents a more cost-effective marine fuel option than ammonia. However in the MCDA covering more aspects we find that ammonia may be almost as interesting for shipping related stakeholders as hydrogen and various biomass-based fuels. Ammonia may to some extent be an interesting future marine fuel option but many issues remain to be solved before large-scale introduction.
Numerical Analysis on the Mechanism of Blast Mitigation by Water Droplets
Sep 2021
Publication
Hydrogen has a high risk of ignition owing to its extremely low ignition energy and wide range of flammability. Therefore acquiring parameters relating to safe usage is of particular interest. The ignition of hydrogen generates combustion processes such as detonation and deflagration which may produce a blast wave. The severity of injuries sustained from a blast wave is determined by its strength. To reduce the physical hazards caused by explosion there is a need for some concepts for attenuating explosions and blast waves. In the present study we used water droplets as a material to reduce the blast wave strength. Numerical analysis of the interaction between blast waves and water droplets in a shock tube was conducted to understand the mitigation mechanism of blast wave. In this report we numerically modelled the experiment conducted by Mataradze et al. [1] to understand the main factor of blast mitigation by water droplets. In order to quantitatively clarify the mitigation effect of water droplets on the blast wave especially by quasi-steady drag here we conducted parameter studies on water droplet sprayed region. From this calculation it was suggested that the location of water droplet sprayed layer did not affect the blast mitigation effect at far side of the high explosives.
Hydrogen Storage in Pure and Boron-Substituted Nanoporous Carbons—Numerical and Experimental Perspective
Aug 2021
Publication
Nanoporous carbons remain the most promising candidates for effective hydrogen storage by physisorption in currently foreseen hydrogen-based scenarios of the world’s energy future. An optimal sorbent meeting the current technological requirement has not been developed yet. Here we first review the storage limitations of currently available nanoporous carbons then we discuss possible ways to improve their storage performance. We focus on two fundamental parameters determining the storage (the surface accessible for adsorption and hydrogen adsorption energy). We define numerically the values nanoporous carbons have to show to satisfy mobile application requirements at pressures lower than 120 bar. Possible necessary modifications of the topology and chemical compositions of carbon nanostructures are proposed and discussed. We indicate that pore wall fragmentation (nano-size graphene scaffolds) is a partial solution only and chemical modifications of the carbon pore walls are required. The positive effects (and their limits) of the carbon substitutions by B and Be atoms are described. The experimental ‘proof of concept’ of the proposed strategies is also presented. We show that boron substituted nanoporous carbons prepared by a simple arc-discharge technique show a hydrogen adsorption energy twice as high as their pure carbon analogs. These preliminary results justify the continuation of the joint experimental and numerical research effort in this field.
From Microcars to Heavy-Duty Vehicles: Vehicle Performance Comparison of Battery and Fuel Cell Electric Vehicles
Oct 2021
Publication
Low vehicle occupancy rates combined with record conventional vehicle sales justify the requirement to optimize vehicle type based on passengers and a powertrain with zero-emissions. This study compares the performance of different vehicle types based on the number of passengers/payloads powertrain configuration (battery and fuel cell electric configurations) and drive cycles to assess range and energy consumption. An adequate choice of vehicle segment according to the real passenger occupancy enables the least energy consumption. Vehicle performance in terms of range points to remarkable results for the FCEV (fuel cell electric vehicle) compared to BEV (battery electric vehicle) where the former reached an average range of 600 km or more in all different drive cycles while the latter was only cruising nearly 350 km. Decisively the cost analysis indicated that FCEV remains the most expensive option with base cost three-fold that of BEV. The FCEV showed notable results with an average operating cost of less than 7 cents/km where BEV cost more than 10 €/km in addition to the base cost for light-duty vehicles. The cost analysis for a bus and semi-truck showed that with a full payload FCPT (fuel cell powertrain) would be more economical with an average energy cost of ~1.2 €/km while with BPT the energy cost is more than 300 €/km
Enabling the Scale Up of Green Hydrogen in Ireland by Decarbonising the Haulage Sector
Jul 2022
Publication
The current research on green hydrogen can focus from the perspective of production but understanding the demand side is equally important to the initial creation of a hydrogen ecosystem in countries with low industrial activities that can utilise large amounts of hydrogen in the short term. Early movers in these countries must create a demand market in parallel with the green hydrogen plant commissioning. This paper presents research that explores the heavy-duty transport sector as a market-of-interest for early deployment of green hydrogen in Ireland. Conducting a survey-based market research amongst this sector indicate significant interest in hydrogen on the island of Ireland and the barriers the participants presented have been overcome in other jurisdictions. The study develops a model to estimate 1.) the annual hydrogen demand and 2.) the corresponding delivery cost to potential hydrogen consumers either directly or to central hydrogen fuelling hubs.
Combination of b-Fuels and e-Fuels—A Technological Feasibility Study
Aug 2021
Publication
The energy supply in Austria is significantly based on fossil natural gas. Due to the necessary decarbonization of the heat and energy sector a switch to a green substitute is necessary to limit CO2 emissions. Especially innovative concepts such as power-to-gas establish the connection between the storage of volatile renewable energy and its conversion into green gases. In this paper different methanation strategies are applied on syngas from biomass gasification. The investigated syngas compositions range from traditional steam gasification sorption-enhanced reforming to the innovative CO2 gasification. As the producer gases show different compositions regarding the H2/COx ratio three possible methanation strategies (direct sub-stoichiometric and over-stoichiometric methanation) are defined and assessed with technological evaluation tools for possible future large-scale set-ups consisting of a gasification an electrolysis and a methanation unit. Due to its relative high share of hydrogen and the high technical maturity of this gasification mode syngas from steam gasification represents the most promising gas composition for downstream methanation. Sub-stoichiometric operation of this syngas with limited H2 dosage represents an attractive methanation strategy since the hydrogen utilization is optimized. The overall efficiency of the sub-stoichiometric methanation lies at 59.9%. Determined by laboratory methanation experiments a share of nearly 17 mol.% of CO2 needs to be separated to make injection into the natural gas grid possible. A technical feasible alternative avoiding possible carbon formation in the methanation reactor is the direct methanation of sorption-enhanced reforming syngas with an overall process efficiency in large-scale applications of 55.9%.
An Adaptive Renewable Energy Plant (AREP) - To Power Local Premises and Vehicles with 100% Renewables
Aug 2021
Publication
An adaptive response renewable energy plant (AREP) that provides grid balancing services and XeV station fuelling services (where “X” is any type) using renewable energy located in urban centres is described. The AREP has its own primary renewable energy sources and adapts operation in the short term to changing levels of excess or deficient energy on LV and MV electricity grids. The AREP adaptively responds by (1) storing excess energy in batteries for the short term and in hydrogen tanks after energy conversion by electrolysers for the long term; (2) returning power to the grid from either the AREP’s own primary (electron-based) energy sources or batteries and/or from hydrogen via conversion in fuel cells; (3) providing electricity for fast charging BeVs and PHeVs and hydrogen for FCeVs; and (4) exporting excess stored energy as hydrogen to domestic markets. The AREP also adapts over the long term by predictive planning of charging capacity such that the type and capacity of renewable energy equipment is optimised for future operations. A key advantage of this AREP configuration is a flexible “plug and play” capability with modular extension of energy assets. If the AREP footprint is constrained interaction with neighbouring AREPs as a mini-VPP-AREP network can assist in balancing short-term operating requirements. The benefits of this grid balancing and XeV renewable energy filling station or AREP are environmental social and economic through efficient functionality of appropriately sized components. AREPs provide a net zero emissions electricity solution to an existing network with short and long-term storage options as well as a net zero emissions fuel alternative to the transport sector while leveraging existing infrastructure with minimal upfront CAPEX. AREPs can give the flexibility a grid needs to enable high levels of renewable installations while developing green hydrogen production.
Optimal Configuration of Multi-Energy Storage in an Electric–Thermal–Hydrogen Integrated Energy System Considering Extreme Disaster Scenarios
Mar 2024
Publication
Extreme disasters have become increasingly common in recent years and pose significant dangers to the integrated energy system’s secure and dependable energy supply. As a vital part of an integrated energy system the energy storage system can help with emergency rescue and recovery during major disasters. In addition it can improve energy utilization rates and regulate fluctuations in renewable energy under normal conditions. In this study the sizing scheme of multienergy storage equipment in the electric–thermal–hydrogen integrated energy system is optimized; economic optimization in the regular operating scenario and resilience enhancement in extreme disaster scenarios are also considered. A refined model of multi-energy storage is constructed and a two-layer capacity configuration optimization model is proposed. This model is further enhanced by the integration of a Markov two-state fault transmission model which simulates equipment defects and improves system resilience. The optimization process is solved using the tabu chaotic quantum particle swarm optimization (TCQPSO) algorithm to provide reliable and accurate optimization results. The results indicate that addressing severe disaster situations in a capacity configuration fully leverages the reserve energy function of energy storage and enhances system resilience while maintaining economic efficiency; furthermore adjusting the load loss penalty coefficients offers a more targeted approach to the balancing of the system economy and resilience. Thus new algorithmic choices and planning strategies for future research on enhancing the resilience of integrated energy systems under extreme disaster scenarios are provided.
An Investigation into the Change Leakage when Switching from Natural Gas to Hydrogen in the UK Gas Distribution Network
Sep 2021
Publication
The H21 National Innovation Competition project is examining the feasibility of repurposing the existing GB natural gas distribution network for transporting 100% hydrogen. It aims to undertake an experimental testing programme that will provide the necessary data to quantify the comparative risk between a 100% hydrogen network and the natural gas network. The first phase of the project focuses on leakage testing of a strategic set of assets that have been removed from service which provide a representative sample of assets across the network. This paper presents the work undertaken for Phase 1A (background testing) where HSE and industry partners have tested a range of natural gas pipework assets of varying size material age and pressure-rating in a new bespoke open-air testing facility at the HSE Science and Research Centre Buxton. The assets have been pressurised with hydrogen and then methane and the leakage rate from the assets measured in both cases. The main finding of this work is that the assets tested which leak hydrogen also leak methane. None of the assets were found to leak hydrogen but not methane. In addition repair techniques that were effective at stopping methane leaks were also effective at stopping hydrogen leaks. The data from the experiments have been interpreted to obtain a range of leakage ratios between the two gases for releases under different conditions. This has been compared to the predicted ratio of hydrogen to methane volumetric leak rates for laminar (1.2:1) and turbulent (2.9:1) releases and good agreement was observed.
Coupling Combustion Simulation and Primary Evaluation of an Asymmetric Motion Diesel Pilot Hydrogen Engine
Jul 2022
Publication
The thermal efficiency and combustion of conventional hydrogen engines cannot be optimized and improved by its symmetric reciprocating. This article introduces an asymmetric motion hydrogen engine (AHE) and investigates its combustion characteristics using diesel pilot ignition. A dynamic model is firstly proposed to describe the asymmetric motion of the AHE and then it is coupled into a multidimensional model for combustion simulation. The effect of asymmetric motion on the AHE combustion is also analyzed by comparing with a corresponding conventional symmetric hydrogen engine (SHE). The results show that the AHE moves slower in compression and faster in expansion than the SHE which brings about higher hydrogen-air mixing level for combustion. The asymmetric motion delays diesel injection to ignite the AHE and its combustion appears later than the SHE which leads to lower pressure and temperature for reducing NO formation. However the AHE faster expansion has a more severe post-combustion effect to reduce isovolumetric heat release level and decrease the energy efficiency.
Review of Life Cycle Assessments for Steel and Environmental Analysis of Future Steel Production Scenarios
Oct 2022
Publication
The steel industry is focused on reducing its environmental impact. Using the life cycle assessment (LCA) methodology the impacts of the primary steel production via the blast furnace route and the scrap-based secondary steel production via the EAF route are assessed. In order to achieve environmentally friendly steel production breakthrough technologies have to be implemented. With a shift from primary to secondary steel production the increasing steel demand is not met due to insufficient scrap availability. In this paper special focus is given on recycling methodologies for metals and steel. The decarbonization of the steel industry requires a shift from a coal-based metallurgy towards a hydrogen and electricity-based metallurgy. Interim scenarios like the injection of hydrogen and the use of pre-reduced iron ores in a blast furnace can already reduce the greenhouse gas (GHG) emissions up to 200 kg CO2/t hot metal. Direct reduction plants combined with electrical melting units/furnaces offer the opportunity to minimize GHG emissions. The results presented give guidance to the steel industry and policy makers on how much renewable electric energy is required for the decarbonization of the steel industry
NewGasMet - Flow Metering of Renewable Gases (Biogas, Biomethane, Hydrogen, Syngas and Mixtures with Natural Gas): Report on the Impact of Renewable Gases, and Mixtures with Natural Gas, on the Accuracy, Cost and Lifetime of Gas Meters
May 2022
Publication
For the usage of domestic gas meters with combustible gases like hydrogen natural gas or mixtures of hydrogen and natural gas in public grids the metrological behaviour of the gas meters has to fulfil the requirements described in the Measuring Instrument Directive (MID). The MID requires also that a measuring instrument shall be suitable for the application. The tightness of a meter is required in order to obtain correct results in case of accuracy tests but also for an application in the grid or for durability tests to avoid risks such as explosive gas mixtures. Due to the different properties of renewable gases leak tightness to one gas mixtures does not necessarily imply leak tightness for other gases. Hydrogen molecules are smaller than those in conventional natural gas which can more easily result in a gas leakage. The EMPIR project NEWGASMET includes beside metrological investigations also a durability test with hydrogen. In order to carry out these activities but also for further hydrogen leakage investigations for instance the investigation of proper seal materials used in the gas meter installation a reliable gas tightness test was developed.
Coal Decarbonization: A State-of-the-art Review of Enhanced Hydrogen Production in Underground Coal Gasification
Aug 2022
Publication
The world is endowed with a tremendous amount of coal resources which are unevenly distributed in a few nations. While sustainable energy resources are being developed and deployed fossil fuels dominate the current world energy consumption. Thus low-carbon clean technologies like underground coal gasification (UCG) ought to play a vital role in energy supply and ensuring energy security in the foreseeable future. This paper provides a state-of-the-art review of the world's development of UCG for enhanced hydrogen production. It is revealed that the world has an active interest in decarbonizing the coal industry for hydrogen-oriented research in the context of UCG. While research is ongoing in multiple coal-rich nations China dominates the world's efforts in both industrial-scale UCG pilots and laboratory experiments. A variety of coal ranks were tested in UCG for enhanced hydrogen output and the possibilities of linking UCG with other prospective technologies had been proposed and critically scrutinized. Moreover it is found that transborder collaborations are in dire need to propel a faster commercialization of UCG in an ever-more carbon-conscious world. Furthermore governmental and financial support is necessary to incentivize further UCG development for large-scale hydrogen production.
Evidence Base Utilised to Justify a Hydrogen Blend Gas Network Safety Case
Sep 2021
Publication
Blending hydrogen with natural gas up to 20 % mol/mol has been identified as a key enabler of hydrogen deployment within the UK gas network. This work outlines the evidence base generated to form the basis of safety submitted to the Health and Safety Executive (HSE) to justify a demonstration of hydrogen blending on a live public gas network within the UK supplying a hydrogen blend to 668homes over the course of 10 months. An evidence base to demonstrate that gas users are not prejudiced by the addition of hydrogen is required by the Gas Safety (Management) Regulations [1] to allow hydrogen distribution above the 0.1 mol% limit specified within the regulations. The technical evidence generated to support the safety case presented to the HSE concerned the implications of introducing a hydrogen blend on appliance operation materials gas characteristics and operational procedures. The outputs of the technical evidence workstreams provided input data to a Quantitative Risk Assessment (QRA) of the GB gas distribution network. The QRA was developed in support of the safety case to allow a causal understanding of public risk to be understood where harm due to gas usage was defined as risk to life caused either by carbon monoxide poisoning or as a result of fires/explosions. Public records were used to calibrate and validate the base risk model to understand the dynamics of public risk due to natural gas usage. The experimental and analytical results of the technical workstreams were then used to derive risk model inputs relating to a hydrogen blend. This allowed a quantified comparison of risk to be understood to demonstrate parity of safety between natural gas and a hydrogen blend. This demonstration of risk parity is a condition precedent of allowing the distribution and utilisation of hydrogen blends within the GB gas network.
Ultra-Cheap Renewable Energy as an Enabling Technology for Deep Industrial Decarbonization via Capture and Utilization of Process CO2 Emissions
Jul 2022
Publication
Rapidly declining costs of renewable energy technologies have made solar and wind the cheapest sources of energy in many parts of the world. This has been seen primarily as enabling the rapid decarbonization of the electricity sector but low-cost low-carbon energy can have a great secondary impact by reducing the costs of energy-intensive decarbonization efforts in other areas. In this study we consider by way of an exemplary carbon capture and utilization cycle based on mature technologies the energy requirements of the “industrial carbon cycle” an emerging paradigm in which industrial CO2 emissions are captured and reprocessed into chemicals and fuels and we assess the impact of declining renewable energy costs on overall economics of these processes. In our exemplary process CO2 is captured from a cement production facility via an amine scrubbing process and combined with hydrogen produced by a solar-powered polymer electrolyte membrane using electrolysis to produce methanol. We show that solar heat and electricity generation costs currently realized in the Middle East lead to a large reduction in the cost of this process relative to baseline assumptions found in published literature and extrapolation of current energy price trends into the near future would bring costs down to the level of current fossil-fuel-based processes.
Underground Hydrogen Storage: Application of Geochemical Modelling in a Case Study in the Molasse Basin, Upper Austria
Feb 2019
Publication
Hydrogen storage in depleted gas fields is a promising option for the large-scale storage of excess renewable energy. In the framework of the hydrogen storage assessment for the “Underground Sun Storage” project we conduct a multi-step geochemical modelling approach to study fluid–rock interactions by means of equilibrium and kinetic batch simulations. With the equilibrium approach we estimate the long-term consequences of hydrogen storage whereas kinetic models are used to investigate the interactions between hydrogen and the formation on the time scales of typical storage cycles. The kinetic approach suggests that reactions of hydrogen with minerals become only relevant over timescales much longer than the considered storage cycles. The final kinetic model considers both mineral reactions and hydrogen dissolution to be kinetically controlled. Interactions among hydrogen and aqueous-phase components seem to be dominant within the storage-relevant time span. Additionally sensitivity analyses of hydrogen dissolution kinetics which we consider to be the controlling parameter of the overall reaction system were performed. Reliable data on the kinetic rates of mineral dissolution and precipitation reactions specifically in the presence of hydrogen are scarce and often not representative of the studied conditions. These uncertainties in the kinetic rates for minerals such as pyrite and pyrrhotite were investigated and are discussed in the present work. The proposed geochemical workflow provides valuable insight into controlling mechanisms and risk evaluation of hydrogen storage projects and may serve as a guideline for future investigations.
The Role of Hydrogen in Heavy Transport to Operate within Planetary Boundaries
Jul 2021
Publication
Green hydrogen i.e. produced from renewable resources is attracting attention as an alternative fuel for the future of heavy road transport and long-distance driving. However the benefits linked to zero pollution at the usage stage can be overturned when considering the upstream processes linked to the raw materials and energy requirements. To better understand the global environmental implications of fuelling heavy transport with hydrogen we quantified the environmental impacts over the full life cycle of hydrogen use in the context of the Planetary Boundaries (PBs). The scenarios assessed cover hydrogen from biomass gasification (with and without carbon capture and storage [CCS]) and electrolysis powered by wind solar bioenergy with CCS nuclear and grid electricity. Our results show that the current diesel-based-heavy transport sector is unsustainable due to the transgression of the climate change-related PBs (exceeding standalone by two times the global climate-change budget). Hydrogen-fuelled heavy transport would reduce the global pressure on the climate change-related PBs helping the transport sector to stay within the safe operating space (i.e. below one-third of the global ecological budget in all the scenarios analysed). However the best scenarios in terms of climate change which are biomass-based would shift burdens to the biosphere integrity and nitrogen flow PBs. In contrast burden shifting in the electrolytic scenarios would be negligible with hydrogen from wind electricity emerging as an appealing technology despite attaining higher carbon emissions than the biomass routes
The Direct Reduction of Iron Ore with Hydrogen
Aug 2022
Publication
The steel industry represents about 7% of the world’s anthropogenic CO2 emissions due to the high use of fossil fuels. The CO2 -lean direct reduction of iron ore with hydrogen is considered to offer a high potential to reduce CO2 emissions and this direct reduction of Fe2O3 powder is investigated in this research. The H2 reduction reaction kinetics and fluidization characteristics of fine and cohesive Fe2O3 particles were examined in a vibrated fluidized bed reactor. A smooth bubbling fluidization was achieved. An increase in external force due to vibration slightly increased the pressure drop. The minimum fluidization velocity was nearly independent of the operating temperature. The yield of the direct H2 -driven reduction was examined and found to exceed 90% with a maximum of 98% under the vibration of ~47 Hz with an amplitude of 0.6 mm and operating temperatures close to 500 ◦C. Towards the future of direct steel ore reduction cheap and “green” hydrogen sources need to be developed. H2 can be formed through various techniques with the catalytic decomposition of NH3 (and CH4 ) methanol and ethanol offering an important potential towards production cost yield and environmental CO2 emission reductions.
Green Hydrogen in Europe: Do Strategies Meet Expectations?
Dec 2021
Publication
The possibility of producing hydrogen as an energy carrier or raw material through electrolysis of water so-called green hydrogen has been on the table as a technological option for a long time. However low conversion efficiency and a dubious climate balance have stood in the way of large-scale application ever since. Within the last three to four years however this view has changed significantly. In addition to technological improvements the increasing speed of the expansion of volatile renewable energies in Europe has also contributed to this since in principle a nearly climate-neutral utilisation of excess generation is possible through the use of hydrogen as an energy carrier in electrolysis. In addition hydrogen or products derived from it can be used in a variety of ways as a final energy carrier in all energy-intensive activities: industry heating and transport. For this reason green hydrogen production could play a key role in interconnecting all energy consuming sectors (sector coupling) a long-term goal necessary for achieving the decarbonisation of the European economy.
Risks and Opportunities Associated with Decarbonising Rotterdam’s Industrial Cluster
Jun 2019
Publication
The Port of Rotterdam is an important industrial cluster comprising mainly oil refining chemical production and power generation. In 2016 the port’s industry accounted for 19% of the Netherlands’ total CO2 emissions. The Port of Rotterdam Authority is aware that the cluster is heavily exposed to future decarbonisation policies as most of its activities focus on trading handling converting and using fossil fuels. Based on a study for the Port Authority using a mixture of qualitative and quantitative methods our article explores three pathways whereby the port’s industry can maintain its strong position while significantly reducing its CO2 emissions and related risks by 2050. The pathways differ in terms of the EU’s assumed climate change mitigation ambitions and the key technological choices made by the cluster’s companies. The focus of the paper is on identifying key risks associated with each scenario and ways in which these could be mitigated.
Dynamic Quality Tracking of Natural Gas and Hydrogen Mixture in a Portion of Natural Gas Grid
Aug 2015
Publication
Direct injection of alternative fuels (biomethane hydrogen) in the natural gas grid appears to be a promising solution to reach environmental objectives of CO2 emission reduction in the current energy scenario. This approach is justified by the large amount of biogas producible which can be upgraded to biomethane; while another proposed solution to increase renewable energy sources exploitation lies in producing hydrogen from excess wind energy followed by injection in the natural gas grid. Nevertheless compliance with composition limits and quality constraints in the resulting natural gas mixture has to be analysed in both stationary and dynamic operations tracking the gas quality downstream the injection point of the alternative fuels. A model was developed to simulate unsteady operation of a portion of gas grid dealing with realistic industrial and residential consumptions concentrated in offtake points. Two case studies were investigated focusing on the comparison between different amounts of hydrogen injection in the pure natural gas flow yielding composition flow rate and pressure profiles. The analysis shows how imposed quality thresholds can be respected although the hydrogen fraction within the natural gas mixture is highly sensitive to the profile and size of the loads connected to the gas pipeline.
Hubs and Clusters Approach to Unlock the Development of Carbon Capture and Storage - Case Study in Spain
Jul 2021
Publication
Xiaolong Sun,
Juan Alcalde,
Mahdi Bakhtbidar,
Javier Elío,
Víctor Vilarrasa,
Jacobo Canal,
Julio Ballesteros,
Niklas Heinemann,
Stuart Haszeldine,
Andrew Cavanagh,
David Vega-Maza,
Fernando Rubiera,
Roberto Martínez-Orio,
Gareth Johnson,
Ramon Carbonell,
Ignacio Marzan,
Anna Travé and
Enrique Gomez-Rivas
Many countries have assigned an indispensable role for carbon capture and storage (CCS) in their national climate change mitigation pathways. However CCS deployment has stalled in most countries with only limited commercial projects realised mainly in hydrocarbon-rich countries for enhanced oil recovery. If the Paris Agreement is to be met then this progress must be replicated widely including hydrocarbon-limited countries. In this study we present a novel source-to-sink assessment methodology based on a hubs and clusters approach to identify favourable regions for CCS deployment and attract renewed public and political interest in viable deployment pathways. Here we apply this methodology to Spain where fifteen emission hubs from both the power and the hard-to-abate industrial sectors are identified as potential CO2 sources. A priority storage structure and two reserves for each hub are selected based on screening and ranking processes using a multi-criteria decision-making method. The priority source-to-sink clusters are identified indicating four potential development regions with the North-Western and North-Eastern Spain recognised as priority regions due to resilience provided by different types of CO2 sources and geological structures. Up to 68.7 Mt CO2 per year comprising around 21% of Spanish emissions can be connected to clusters linked to feasible storage. CCS especially in the hard-to-abate sector and in combination with other low-carbon energies (e.g. blue hydrogen and bioenergy) remains a significant and unavoidable contributor to the Paris Agreement’s mid-century net-zero target. This study shows that the hubs and clusters approach can facilitate CCS deployment in Spain and other hydrocarbon-limited countries.
NewGasMet - Flow Metering of Renewable Gases (Biogas, Biomethane, Hydrogen, Syngas and Mixtures with Natural Gas): Effect of the Renewable Gases on the Uncertainty Budgets of Gas Meters
Sep 2022
Publication
During the study of the CEN/TC 237 standards “Gas meters” in the European Metrology Programme for Innovation and Research (EMPIR) project named NEWGASMET the impact of the renewable gases (biogas biomethane hydrogen syngas and mixtures with natural gas) on the uncertainty on the gas meter was discussed and described in several recommendation reports. This report is on the activity A2.1.15 where the objective is “Using input from A2.1.2-A2.1.8 FORCE with support from Cesame CMI NEL PTB VSL and ISSI will write a report on the effects of renewable gases on the uncertainty budgets of gas meters.”
A Comprehensive Review of Electrochemical Hybrid Power Supply Systems and Intelligent Energy Managements for Unmanned Aerial Vehicles in Public Services
Jun 2022
Publication
The electric unmanned aerial vehicles (UAVs) are rapidly growing due to their abilities to perform some difficult or dangerous tasks as well as many public services including real-time monitoring wireless coverage search and rescue wildlife surveys and precision agriculture. However the electrochemical power supply system of UAV is a critical issue in terms of its energy/power densities and lifetime for service endurance. In this paper the current power supply systems used in UAVs are comprehensively reviewed and analyzed on the existing power configurations and the energy management systems. It is identified that a single type of electrochemical power source is not enough to support a UAV to achieve a long-haul flight; hence a hybrid power system architecture is necessary. To make use of the advantages of each type of power source to increase the endurance and achieve good performance of the UAVs the hybrid systems containing two or three types of power sources (fuel cell battery solar cell and supercapacitor) have to be developed. In this regard the selection of an appropriate hybrid power structure with the optimized energy management system is critical for the efficient operation of a UAV. It is found that the data-driven models with artificial intelligence (AI) are promising in intelligent energy management. This paper can provide insights and guidelines for future research and development into the design and fabrication of the advanced UAV power systems.
Analysis of the Use of Recycled Aluminum to Generate Green Hydrogen in an Electric Bicycle
Feb 2023
Publication
This article proposes using recycled aluminum generating hydrogen in situ at low pressure to power a 250 W electric bicycle with a fuel cell (FC) to increase the average speed and autonomy compared to a conventional electric bicycle with a battery. To generate hydrogen the aluminum–water reaction with a 6 M NaOH solution is used as a catalyst. This article details the parts of the generation system the electronic configuration used the aluminum- and reagent-loading procedure and the by-products obtained as well as the results of the operation without pedaling with a resistance equivalent to a flat terrain and at maximum power of the accelerator for one and two loads of about 100 g of aluminum each. This allows us to observe different hybrid strategies with a low-capacity battery in each case. The goal is to demonstrate that it is possible to store energy in a long-lasting transportable low-pressure and sustainable manner using recycled-aluminum test tubes and to apply this to mobility
Photocatalytic Water Splitting: How Far Away Are We from Being Able to Industrially Produce Solar Hydrogen?
Oct 2022
Publication
Solar water splitting (SWS) has been researched for about five decades but despite successes there has not been a big breakthrough advancement. While the three fundamental steps light absorption charge carrier separation and diffusion and charge utilization at redox sites are given a great deal of attention either separately or simultaneously practical considerations that can help to increase efficiency are rarely discussed or put into practice. Nevertheless it is possible to increase the generation of solar hydrogen by making a few little but important adjustments. In this review we talk about various methods for photocatalytic water splitting that have been documented in the literature and importance of the thin film approach to move closer to the large-scale photocatalytic hydrogen production. For instance when comparing the film form of the identical catalyst to the particulate form it was found that the solar hydrogen production increased by up to two orders of magnitude. The major topic of this review with thin-film forms is discussion on several methods of increased hydrogen generation under direct solar and one-sun circumstances. The advantages and disadvantages of thin film and particle technologies are extensively discussed. In the current assessment potential approaches and scalable success factors are also covered. As demonstrated by a film-based approach the local charge utilization at a zero applied potential is an appealing characteristic for SWS. Furthermore we compare the PEC-WS and SWS for solar hydrogen generation and discuss how far we are from producing solar hydrogen on an industrial scale. We believe that the currently employed variety of attempts may be condensed to fewer strategies such as film-based evaluation which will create a path to address the SWS issue and achieve sustainable solar hydrogen generation.
Pore-scale Study of Microbial Hydrogen Consumption and Wettability Alteration During Underground Hydrogen Storage
Feb 2023
Publication
Hydrogen can be a renewable energy carrier and is suggested to store renewable energy and mitigate carbon dioxide emissions. Subsurface storage of hydrogen in salt caverns deep saline formations and depleted oil/gas reservoirs would help to overcome imbalances between supply and demand of renewable energy. Hydrogen however is one of the most important electron donors for many subsurface microbial processes including methanogenesis sulfate reduction and acetogenesis. These processes cause hydrogen loss and changes of reservoir properties during geological hydrogen storage operations. Here we report the results of a typical halophilic sulfate-reducing bacterium growing in a microfluidic pore network saturated with hydrogen gas at 35 bar and 37°C. Test duration is 9 days. We observed a significant loss of H2 from microbial consumption after 2 days following injection into a microfluidic device. The consumption rate decreased over time as the microbial activity declined in the pore network. The consumption rate is influenced profoundly by the surface area of H2 bubbles and microbial activity. Microbial growth in the silicon pore network was observed to change the surface wettability from a water-wet to a neutral-wet state. Due to the coupling effect of H2 consumption by microbes and wettability alteration the number of disconnected H2 bubbles in the pore network increased sharply over time. These results may have significant implications for hydrogen recovery and gas injectivity. First pore-scale experimental results reveal the impacts of subsurface microbial growth on H2 in storage which are useful to estimate rapidly the risk of microbial growth during subsurface H2 storage. Second microvisual experiments provide critical observations of bubble-liquid interfacial area and reaction rate that are essential to the modeling that is needed to make long-term predictions. Third results help us to improve the selection criteria for future storage sites.
A Robust Scheduling Methodology for Integrated Electric-Gas System Considering Dynamics of Natural Gas Pipeline and Blending Hydrogen
Mar 2022
Publication
As smart grid develops and renewables advance challenges caused by uncertainties of renewables have been seriously threatening the energy system’s safe operation. Nowadays the integrated electric-gas system (IEGS) plays a significant role in promoting the flexibility of modern grid owing to its great characteristic in accommodating renewable energy and coping with fluctuation and uncertainty of the system. And hydrogen as an emerging and clean energy carrier can further enhance the energy coupling of the IEGS and promote carbon neutralization with the development of power-to-hydrogen (P2H) technology and technology of blending hydrogen in the natural gas system. Dealing with the uncertainty of renewables a robust schedule optimization model for the integrated electric and gas systems with blending hydrogen (IEGSH) considering the dynamics of gas is proposed and the iterative solving method based on column-and-constraint generation (C&CG) algorithm is implemented to solve the problem. Case studies on the IEGSH consisting of IEEE 39-bus power system and 27-node natural gas system validate the effectiveness of the dynamic energy flow model in depicting the transient process of gas transmission. The effectiveness of the proposed robust day-ahead scheduling model in dealing with the intra-day uncertainty of wind power is also verified. Additionally the carbon emission reduction resulting from the blending of hydrogen is evaluated.
Feasibility of Hydrogen Storage in Depleted Hydrocarbon Chalk Reservoirs: Assessment of Biochemical and Chemical Effects
Jul 2022
Publication
Hydrogen storage is one of the energy storage methods that can help realization of an emission free future by saving surplus renewable energy for energy deficit periods. Utilization of depleted hydrocarbon reservoirs for large-scale hydrogen storage may be associated with the risk of chemical/biochemical reactions. In the specific case of chalk reservoirs the principal reactions are abiotic calcite dissolution acetogenesis methanogenesis and biological souring. Here we use PHREEQC to evaluate the dynamics and the extent of hydrogen loss by each of these reactions in hydrogen storage scenarios for various Danish North Sea chalk hydrocarbon reservoirs. We find that: (i) Abiotic calcite dissolution does not occur in the temperature range of 40-180◦ C. (ii) If methanogens and acetogens grow as slow as the slowest growing methanogens and acetogens reported in the literature methanogenesis and acetogenesis cannot cause a hydrogen loss more than 0.6% per year. However (iii) if they proceed as fast as the fastest growing methanogens and acetogens reported in the literature a complete loss of all injected hydrogen in less than five years is possible. (iv) Co-injection of CO2 can be employed to inhibit calcite dissolution and keep the produced methane due to methanogenesis carbon neutral. (v) Biological sulfate reduction does not cause significant hydrogen loss during 10 years but it can lead to high hydrogen sulfide concentrations (1015 ppm). Biological sulfate reduction is expected to impact hydrogen storage only in early stages if the only source of sulfur substrates are the dissolved species in the brine and not rock minerals. Considering these findings we suggest that depleted chalk reservoirs may not possess chemical/biochemical risks and be good candidates for large-scale underground hydrogen storage.
A Study on Green Hydrogen-based Isolated Microgrid
Oct 2022
Publication
This paper assesses the techno-economic feasibility of a green hydrogen-based microgrid for a remote Australian island. Hydrogen can be used to provide clean energy in areas where large-scale renewable energy sources are not feasible owing to geography government regulations or regulatory difficulties. This study not only identifies the appropriate component size for a hydrogen-based microgrid but also provides an economic perspective of decarbonising Thursday Island in Torres Straits Queensland Australia. Due to geographical constraints the green hydrogen production system needs to be distinct from the electrical network. This research shows how to produce green hydrogen transport it and generate power at a low cost. The study was performed utilising the HOMER simulation platform to find the least cost solution. The simulation results demonstrate an AU$0.01 reduction in Levelised Cost of Energy compared to the present electricity generation cost which is AU$0.56. The inclusion of a green hydrogen system will potentially minimise CO2 emissions by 99.6% while ensuring almost 100% renewable penetration. The results of this study will also serve as a guide for the placement of hydrogen-based microgrids in similar remote locations around the world where numerous remote energy systems are located close to each other.
Hydrogen Production through Autothermal Reforming of Ethanol: Enhancement of Ni Catalyst Performance via Promotion
Aug 2021
Publication
Autothermal reforming of bioethanol (ATR of C2H5OH) over promoted Ni/Ce0.8La0.2O1.9 catalysts was studied to develop carbon-neutral technologies for hydrogen production. The regulation of the functional properties of the catalysts was attained by adjusting their nanostructure and reducibility by introducing various types and content of M promoters (M = Pt Pd Rh Re; molar ratio M/Ni = 0.003–0.012). The composition–characteristics–activity correlation was determined using catalyst testing in ATR of C2H5OH thermal analysis N2 adsorption X-ray diffraction transmission electron microscopy and EDX analysis. It was shown that the type and content of the promoter as well as the preparation mode (combined or sequential impregnation methods) determine the redox properties of catalysts and influence the textural and structural characteristics of the samples. The reducibility of catalysts improves in the following sequence of promoters: Re < Rh < Pd < Pt with an increase in their content and when using the co-impregnation method. It was found that in ATR of C2H5OH over bimetallic Ni-M/Ce0.8La0.2O1.9 catalysts at 600 ◦C the hydrogen yield increased in the following row of promoters: Pt < Rh < Pd < Re at 100% conversion of ethanol. The introduction of M leads to the formation of a NiM alloy under reaction conditions and affects the resistance of the catalyst to oxidation sintering and coking. It was found that for enhancing Ni catalyst performance in H2 production through ATR of C2H5OH the most effective promotion is with Re: at 600 ◦C over the optimum 10Ni-0.4Re/Ce0.8La0.2O1.9 catalyst the highest hydrogen yield 65% was observed.
Application of Pipeline QRA Methodologies to Hydrogen Pipelines in Support of the Transition to a Decarbonised Future
Sep 2021
Publication
Hydrogen is expected to play a key role in the decarbonised future of energy. For hydrogen distribution pipelines are seen as the main method for mass transport of hydrogen gas. To support the evaluation of risk related to hydrogen pipelines a revised QRA methodology is presented based on currently available and industry accepted guidance related to natural gas. The QRA approach is primarily taken from HSE UK’s MISHAP methodology [1]. The base methodology is reviewed and modifications suggested to adapt it for use with hydrogen gas transport. Compared to natural gas it was found that the escape distances for hydrogen (based on the degree of heat flux) were lower. However as for the overall risk for both individual and societal the case with hydrogen was more severe close to the pipeline. This was driven by the increased ignition probability of hydrogen. The approach may be used as part of the review and appraisal process of hydrogen projects
Economic Analysis of a Zero-carbon Liquefied Hydrogen Tanker Ship
Jun 2022
Publication
The green hydrogen economy is considered one of the sustainable solutions to mitigate climate change. This study provides an economic analysis of a novel liquified hydrogen (LH2) tanker fuelled by hydrogen with a total capacity of ~280000 m3 of liquified hydrogen named ‘JAMILA’. An established economic method was applied to investigate the economic feasibility of the JAMILA ship as a contribution to the future zero-emission target. The systematic economic evaluation determined the net present value of the LH2 tanker internal rate of return payback period and economic value added to support and encourage shipyards and the industrial sector in general. The results indicate that the implementation of the LH2 tanker ship can cover the capital cost of the ship within no more than 2.5 years which represents 8.3% of the assumed 30-year operational life cycle of the project in the best maritime shipping prices conditions and 6 years in the worst-case shipping marine economic conditions. Therefore the assessment of the economic results shows that the LH2 tankers may be a worthwhile contribution to the green hydrogen economy.
Islanded Ammonia Power Systems: Technology Review & Conceptual Process Design
Aug 2019
Publication
Recent advances in technologies for the decentralized islanded ammonia economy are reviewed with an emphasis on feasibility for long-term practical implementation. The emphasis in this review is on storage systems in the size range of 1–10 MW. Alternatives for hydrogen production nitrogen production ammonia synthesis ammonia separation ammonia storage and ammonia combustion are compared and evaluated. A conceptual process design based on the optimization of temperature and pressure levels of existing and recently proposed technologies is presented for an islanded ammonia energy system. This process design consists of wind turbines and solar panels for electricity generation a battery for short-term energy storage an electrolyzer for hydrogen production a pressure swing adsorption unit for nitrogen production a novel ruthenium-based catalyst for ammonia synthesis a supported metal halide for ammonia separation and storage and an ammonia fueled proton-conducting solid oxide fuel cell for electricity generation. In a generic location in northern Europe it is possible to operate the islanded energy system at a round-trip efficiency of 61% and at a cost of about 0.30–0.35 € kWh−1 .
Comparative Levelized Cost Analysis of Transmitting Renewable Solar Energy
Feb 2023
Publication
A bottom-up cost analysis for delivering utility-scale PV-generated electricity as hydrogen through pipelines and as electricity through power is undertaken. Techno-economic generation and demand data for California are used to calculate the levelized cost of transmitting (LCOT) energy and the levelized cost of electricity (LCOE) prior to distribution. High-voltage levels of 230 kV and 500 kV and 24-inch and 36-inch pipelines for 100 to 700 miles of transmission are considered. At 100 miles of transmission the cost of transmission between each medium is comparable. At longer distances the pipeline scenarios become increasingly cheaper at low utilization levels. The all-electric pathways utilizing battery energy storage systems can meet 95% of the load for as low as 356 USD/MWh whereas when meeting 100% of load with the hydrogen gas turbine and fuel cell pathways the costs are 278 and 322 USD/MWh respectively.
Opportunities and Limitations of Hydrogen Energy in Poland against the Background of the European Union Energy Policy
Jul 2022
Publication
One of the strategic goals of developed countries is to significantly increase the share of renewable energy sources in electricity generation. However the process may be hindered by e.g. the storage and transport of energy from renewable sources. The European Union countries see the development of the hydrogen economy as an opportunity to overcome this barrier. Therefore since 2020 the European Union has been implementing a hydrogen strategy that will increase the share of hydrogen in the European energy mix from the current 2 percent to up to 13–14 percent by 2050. In 2021 following the example of other European countries the Polish government adopted the Polish Hydrogen Strategy until 2030 with an outlook until 2040 (PHS). However the implementation of the strategy requires significant capital expenditure and infrastructure modernisation which gives rise to question as to whether Poland is likely to achieve the goals set out in the Polish Hydrogen Strategy and European Green Deal. The subject of the research is an analysis of the sources of financing for the PHS against the background of solutions implemented by the EU countries and a SWOT/TOWS analysis on the hydrogen economy in Poland. The overall result of the SWOT/TOWS analysis shows the advantage of strengths and related opportunities. This allows for a positive assessment of the prospects for the hydrogen economy in Poland. Poland should continue its efforts to take advantage of the external factors (O/S) such as EU support an increased price competitiveness of hydrogen and the emergence of a competitive cross-border hydrogen market in Europe. At the same time the Polish authorities should not forget about the weaknesses and threats that may inhibit the development of the domestic hydrogen market. It is necessary to modernise the infrastructure; increase the share of renewable energy sources in hydrogen production; increase R&D expenditure and in particular to complete the negotiations related to the adoption of the Fit for 55 package.
Non-Precious Electrodes for Practical Alkaline Water Electrolysis
Apr 2019
Publication
Water electrolysis is a promising approach to hydrogen production from renewable energy sources. Alkaline water electrolyzers allow using non-noble and low-cost materials. An analysis of common assumptions and experimental conditions (low concentrations low temperature low current densities and short-term experiments) found in the literature is reported. The steps to estimate the reaction overpotentials for hydrogen and oxygen reactions are reported and discussed. The results of some of the most investigated electrocatalysts namely from the iron group elements (iron nickel and cobalt) and chromium are reported. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The experimental work is done involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at temperatures between 30 and 100 ◦C which are closer to industrial applications than what is usually found in literature. Stable cell components and a good performance was achieved using Raney nickel as a cathode and stainless steel 316L as an anode by means of a monopolar cell at 75 ◦C which ran for one month at 300 mA cm−2 . Finally the proposed catalysts showed a total kinetic overpotential of about 550 mV at 75 ◦C and 1 A cm−2.
A Review on Industrial Perspectives and Challenges on Material, Manufacturing, Design and Development of Compressed Hydrogen Storage Tanks for the Transportation Sector
Jul 2022
Publication
Hydrogen fuel cell technology is securing a place in the future of advanced mobility and the energy revolution as engineers explore multiple paths in the quest for decarbonization. The feasibility of hydrogen-based fuel cell vehicles particularly relies on the development of safe lightweight and cost-competitive solutions for hydrogen storage. After the demonstration of hundreds of prototype vehicles today commercial hydrogen tanks are in the first stages of market introduction adopting configurations that use composite materials. However production rates remain low and costs high. This paper intends to provide an insight into the evolving scenario of solutions for hydrogen storage in the transportation sector. Current applications in different sectors of transport are covered focusing on their individual requirements. Furthermore this work addresses the efforts to produce economically attractive composite tanks discussing the challenges surrounding material choices and manufacturing practices as well as cutting-edge trends pursued by research and development teams. Key issues in the design and analysis of hydrogen tanks are also discussed. Finally testing and certification requirements are debated once they play a vital role in industry acceptance.
Assessing Damaged Pipelines Transporting Hydrogen
Jun 2022
Publication
There is worldwide interest in transporting hydrogen using both new pipelines and pipelines converted from natural gas service. Laboratory tests investigating the effect of hydrogen on the mechanical properties of pipeline steels have shown that even low partial pressures of hydrogen can substantially reduce properties such as reduction in area and fracture toughness and increase fatigue crack growth rates. However qualitative arguments suggest that the effects on pipelines may not be as severe as predicted from the small scale tests. If the trends seen in laboratory tests do occur in service there are implications for the assessment of damage such as volumetric corrosion dents and mechanical interference. Most pipeline damage assessment methods are semi-empirical and have been calibrated with data from full scale tests that did not involve hydrogen. Hence the European Pipeline Research Group (EPRG) commissioned a study to investigate damage assessment methods in the presence of hydrogen. Two example pipeline designs were considered both were assessed assuming a modern high performance material and an older material. From these analyses the numerical results show that the high toughness material will tolerate damage even if the properties are degraded by hydrogen exposure. However low toughness materials may not be able to tolerate some types of severe damage. If the predictions are realistic operators may have to repair more damage or reduce operating pressures. Furthermore damage involving cracking may not Page 2 of 22 satisfy the ASME B31.12 requirements for preventing time dependent crack growth. Further work is required to determine if the effects predicted using small scale laboratory test data will occur in practice.
Strategic Transport Fleet Analysis of Heavy Goods Vehicle Technology for Net-zero Targets
Jul 2022
Publication
This paper addresses the decarbonisation of the heavy-duty transport sector and develops a strategy towards net-zero greenhouse gas (GHG) emissions in heavy-goods vehicles (HGVs) by 2040. By conducting a literature review and a case study on the vehicle fleet of a large UK food and consumer goods retailer the feasibilities of four alternative vehicle technologies are evaluated from environmental economic and technical perspectives. Socio-political factors and commercial readiness are also examined to capture non-technical criteria that influences decision-makers. Strategic analysis frameworks such as PEST-SWOT models were developed for liquefied natural gas biomethane electricity and hydrogen to allow a holistic comparison and identify their long-term deployment potential. Technology innovation is needed to address range and payload limitations of electric trucks whereas government and industry support are essential for a material deployment of hydrogen in the 2030s. Given the UK government’s plan to phase out new diesel HGVs by 2040 fleet operators should commence new vehicle trials by 2025 and replace a considerable amount of their lighter diesel trucks with zero-emission vehicles by 2030 and the remaining heavier truck fleet by 2035.
Optimization of Energy Management Strategy for Fuel Cell Hybrid Electric Vehicles Based on Dynamic Programming
Jun 2022
Publication
Fuel cell hybrid electric vehicles have attracted a large amount of attention in recent years owing to their advantages of zero emissions high efficiency and low noise. To improve the fuel economy and system durability of vehicles this paper proposes an energy management strategy optimization method for fuel cell hybrid electric vehicles based on dynamic programming. Rule-based and dynamic-programming-based strategies are developed based on building a fuel cell/battery hybrid system model. The rule-based strategy is improved with a power distribution scheme of dynamic programming strategy to improve the fuel economy of the vehicle. Furthermore a limit on the rate of change of the output power of the fuel cell system is added to the rule-based strategy to avoid large load changes to improve the durability of the fuel cell. The simulation results show that the equivalent 100 km hydrogen consumption of the strategy based on the dynamic programming optimization rules is reduced by 6.46% compared with that before the improvement and by limiting the rate of change of the output power of the fuel cell system the times of large load changes are reduced. Therefore the strategy based on the dynamic programming optimization rules effectively improves the fuel economy and system durability of vehicles.
Co-gasification of Refuse-derived Fuels and Bituminous Coal with Oxygen/steam Blend to Hydrogen Rich Gas
May 2022
Publication
The gasification technology of refuse-derived fuels (RDF) can represent a future alternative to the global hydrogen production and a pathway for the development of the circular economy. The paper presents an innovative way of utilizing RDF through their oxygen/steam co-gasification with bituminous coal to hydrogen rich gas. Five different RDF samples (RDF1÷RDF5) were investigated. The in-depth analyses of the co-gasification of bituminous coal blends with different amounts of RDF (10 15 and 20%w/w) under various temperature conditions were conducted with the application of Hierarchical Clustering Analysis (HCA). The results of the research study revealed a decrease in the total gas yield as well as in the hydrogen yield observed with the increase in the RDF fraction in the fuel blend. The lowest hydrogen yield and the highest carbon conversion were noted for the co-gasification tests of coal blends with 20%w/w for all the studied RDFs. The SEM-EDS (Scanning Electron Microscopy with Energy Dispersive Spectroscopy) and WDXRF (Wavelength Dispersive X-ray Fluorescence) results showed a significantly higher H2 yield in RDF2 co-gasification with coal in comparison with all the remaining RDFs due to the higher concentration of calcium in the sample. The molecular structure analysis of polymers using Fourier transform infrared spectroscopy (FTIR) demonstrated that the most prevalent synthetic polymers in RDF2 are polyethylene terephthalate and polyvinyl chloride characterized by the lowest thermal stability compared to polyethylene and polypropylene.
Everything About Hydrogen Podcast: Where Does Hydrogen Fit in the Global Energy Transition?
Apr 2022
Publication
On this episode the EAH team discusses the role of hydrogen in the energy transition with Michael Liebreich Chairman and CEO of Liebreich Associates. Michael is an acknowledged thought leader on clean energy mobility technology climate sustainability and finance. He is the founder and senior contributor to Bloomberg New Energy Finance a member of numerous industry governmental and multilateral advisory boards an angel investor a former member of the board of Transport for London and an Advisor to the UK Board of Trade.
The podcast can be found on their website
The podcast can be found on their website
CFD Study of Dual Fuel Combustion in a Research Diesel Engine Fueled by Hydrogen
Jul 2022
Publication
Superior fuel economy higher torque and durability have led to the diesel engine being widely used in a variety of fields of application such as road transport agricultural vehicles earth moving machines and marine propulsion as well as fixed installations for electrical power generation. However diesel engines are plagued by high emissions of nitrogen oxides (NOx) particulate matter (PM) and carbon dioxide when conventional fuel is used. One possible solution is to use low-carbon gaseous fuel alongside diesel fuel by operating in a dual-fuel (DF) configuration as this system provides a low implementation cost alternative for the improvement of combustion efficiency in the conventional diesel engine. An initial step in this direction involved the replacement of diesel fuel with natural gas. However the consequent high levels of unburned hydrocarbons produced due to non-optimized engines led to a shift to carbon-free fuels such as hydrogen. Hydrogen can be injected into the intake manifold where it premixes with air then the addition of a small amount of diesel fuel auto-igniting easily provides multiple ignition sources for the gas. To evaluate the efficiency and pollutant emissions in dual-fuel diesel-hydrogen combustion a numerical CFD analysis was conducted and validated with the aid of experimental measurements on a research engine acquired at the test bench. The process of ignition of diesel fuel and flame propagation through a premixed air-hydrogen charge was represented the Autoignition-Induced Flame Propagation model included ANSYS-Forte software. Because of the inefficient operating conditions associated with the combustion the methodology was significantly improved by evaluating the laminar flame speed as a function of pressure temperature and equivalence ratio using Chemkin-Pro software. A numerical comparison was carried out among full hydrogen full methane and different hydrogen-methane mixtures with the same energy input in each case. The use of full hydrogen was characterized by enhanced combustion higher thermal efficiency and lower carbon emissions. However the higher temperatures that occurred for hydrogen combustion led to higher NOx emissions.
Multi-Time Scale Optimal Scheduling Model of Wind and Hydrogen Integrated Energy System Based on Carbon Trading
Jan 2023
Publication
In the context of carbon trading energy conservation and emissions reduction are the development directions of integrated energy systems. In order to meet the development requirements of energy conservation and emissions reduction in the power grid considering the different responses of the system in different time periods a wind-hydrogen integrated multi-time scale energy scheduling model was established to optimize the energy-consumption scheduling problem of the system. As the scheduling model is a multiobjective nonlinear problem the artificial fish swarm algorithm–shuffled frog leaping algorithm (AFS-SFLA) was used to solve the scheduling model to achieve system optimization. In the experimental test process the Griewank benchmark function and the Rosenbrock function were selected to test the performance of the proposed AFS-SFL algorithm. In the Griewank environment compared to the SFLA algorithm the AFS-SFL algorithm was able to find a feasible solution at an early stage and tended to converge after 110 iterations. The optimal solution was −4.83. In the test of total electric power deviation results at different time scales the maximum deviation of early dispatching was 14.58 MW and the minimum deviation was 0.56 MW. The overall deviation of real-time scheduling was the minimum and the minimum deviation was 0 and the maximum deviation was 1.89 WM. The integrated energy system adopted real-time scale dispatching with good system stability and low-energy consumption. Power system dispatching optimization belongs to the objective optimization problem. The artificial fish swarm algorithm and frog algorithm were innovatively combined to solve the dispatching model which improved the accuracy of power grid dispatching. The research content provides an effective reference for the efficient use of clean and renewable energy.
Vision for a European Metrology Network for Energy Gases
Mar 2022
Publication
As Europe moves towards decarbonising its energy infrastructure new measurement needs will arise that require collaborative efforts between European National Metrology Institutes and Designated Institutes to tackle. Such measurement needs include flow metering of hydrogen or hydrogen enriched natural gas in the gas grid for billing quality assurance of hydrogen at refuelling stations and equations of state for carbon dioxide in carbon capture and storage facilities. The European metrology network for energy gases for the first time provides a platform where metrology institutes can work together to develop a harmonised strategy prioritise new challenges and share expertise and capabilities to support the European energy gas industry to meet stringent EU targets for climate change and emissions reductions
Artificial Intelligence-Based Machine Learning toward the Solution of Climate-Friendly Hydrogen Fuel Cell Electric Vehicles
Jul 2022
Publication
The rapid conversion of conventional powertrain technologies to climate-neutral new energy vehicles requires the ramping of electrification. The popularity of fuel cell electric vehicles with improved fuel economy has raised great attention for many years. Their use of green hydrogen is proposed to be a promising clean way to fill the energy gap and maintain a zero-emission ecosystem. Their complex architecture is influenced by complex multiphysics interactions driving patterns and environmental conditions that put a multitude of power requirements and boundary conditions around the vehicle subsystems including the fuel cell system the electric motor battery and the vehicle itself. Understanding its optimal fuel economy requires a systematic assessment of these interactions. Artificial intelligence-based machine learning methods have been emerging technologies showing great potential for accelerated data analysis and aid in a thorough understanding of complex systems. The present study investigates the fuel economy peaks during an NEDC in fuel cell electric vehicles. An innovative approach combining traditional multiphysics analyses design of experiments and machine learning is an effective blend for accelerated data supply and analysis that accurately predicts the fuel consumption peaks in fuel cell electric vehicles. The trained and validated models show very accurate results with less than 1% error.
Influences on Hydrogen Production at a Wind Farm
Dec 2022
Publication
If an affordable infrastructure for low-carbon-intensity hydrogen can be developed then hydrogen is expected to become a key factor in decarbonizing the atmosphere. This research focuses on factors an existing wind farm operator would consider when weighing participating in the electricity market the hydrogen market or both. The solutions depend on the state of technology which is changing rapidly the local market structures the local natural resources and the local pre-existing infrastructure. Consequently this investigation used an assessment approach that examined the variation of net present value. The investigation identified profitability conditions under three different scenarios: 1) Make and sell what makes economic sense at the time of production 2) Use electrolyzer and fuel cell to consume power from the grid at times of low net demand and to produce electricity at times of high net demand 3) Same as #2 but also market hydrogen directly when profitable.
Techno-Economic Feasibility of a Solar-Wind-Fuel Cell Energy System in Duqm, Oman
Jul 2022
Publication
Duqm is located in the Al Wasta Governorate in Oman and is currently fed by 10 diesel generators with a total capacity of around 76 MW and other rental power sources with a size of 18 MW. To make the electric power supply come completely from renewables one novel solution is to replace the diesel with hydrogen. The extra energy coming from the PV-wind system can be utilized to produce green hydrogen that will be utilized by the fuel cell. Measured data of solar insolation hourly wind speeds and hourly load consumption are used in the proposed system. Finding an ideal configuration that can match the load demand and be suitable from an economic and environmental point of view was the main objective of this research. The Hybrid Optimization Model for Multiple Energy Resources (HOMER Pro) microgrid software was used to evaluate the technical and financial performance. The findings demonstrated that the suggested hybrid system (PV-wind-fuel cell) will remove CO2 emissions at a cost of energy (COE) of USD 0.436/kWh and will reduce noise. With a total CO2 emission of 205676830 kg/year the levelized cost of energy for the current system is USD 0.196/kWh. The levelized cost for the diesel system will rise to USD 0.243/kWh when taking 100 US dollars per ton of CO2 into account. Due to system advantages the results showed that using solar wind and fuel cells is the most practical and cost-effective technique. The results of this research illustrated the feasibility and effectiveness of utilizing wind and solar resources for both hydrogen and energy production and also suggested that hydrogen is a more cost-effective long-term energy storage option than batteries.
Comparison of Alternative Marine Fuels
Sep 2019
Publication
The overall ambition of the study has been to assess the commercial and operational viability of alternative marine fuels based on review existing academic and industry literature. The approach assesses how well six alternative fuels perform compared to LNG fuel on a set of 11 key parameters. Conventional fuels are not covered in this study however 2020 compliant fuels (HFO+scrubber and low sulphur fuels are included in the conclusion for comparative purposes.
Energy Recovery from Wastewater in Mexico: A Systematic Review
Feb 2023
Publication
The usage of fossil fuels to generate energy and the lack of wastewater treatment in Mexico are two issues that can be addressed at the same time while developing wastewater treatment technologies that incorporate energy recovery in their process train. We carried out a systematic review based on the PRISMA methodology to identify and review studies regarding energy recovery using wastewater as a substrate in Mexico. Peer-reviewed papers were identified through Scopus Web of Knowledge and Google Scholar using a timeframe of 22 years that represented from 2000 to 2022. After applying the selection criteria we identified 31 studies to be included in the final review starting from 2007. The kind of energy product type of technology used substrate wastewater amount of energy produced and main parameters for the operation of the technology were extracted from the papers. The results show that methane is the most researched energy recovery product from wastewater followed by hydrogen and electricity and the technology used to archive it is an up-flow anaerobic sludge bed (UASB) reactor to produce methane and hydrogen. In addition microbial fuel cells (MFCs) were preferred to produce electricity. According to our data more energy per kgCOD removed could be obtained with methane-recovering technologies in the Mexican peer-reviewed studies compared with hydrogen recovery and electricity production.
Fundamentals, Materials, and Machine Learning of Polymer Electrolyte Membrane Fuel Cell Technology
Jun 2020
Publication
Polymer electrolyte membrane (PEM) fuel cells are electrochemical devices that directly convert the chemical energy stored in fuel into electrical energy with a practical conversion efficiency as high as 65%. In the past years significant progress has been made in PEM fuel cell commercialization. By 2019 there were over 19000 fuel cell electric vehicles (FCEV) and 340 hydrogen refueling stations (HRF) in the U.S. (~8000 and 44 respectively) Japan (~3600 and 112 respectively) South Korea (~5000 and 34 respectively) Europe (~2500 and 140 respectively) and China (~110 and 12 respectively). Japan South Korea and China plan to build approximately 3000 HRF stations by 2030. In 2019 Hyundai Nexo and Toyota Mirai accounted for approximately 63% and 32% of the total sales with a driving range of 380 and 312 miles and a mile per gallon (MPGe) of 65 and 67 respectively. Fundamentals of PEM fuel cells play a crucial role in the technological advancement to improve fuel cell performance/durability and reduce cost. Several key aspects for fuel cell design operational control and material development such as durability electrocatalyst materials water and thermal management dynamic operation and cold start are briefly explained in this work. Machine learning and artificial intelligence (AI) have received increasing attention in material/energy development. This review also discusses their applications and potential in the development of fundamental knowledge and correlations material selection and improvement cell design and optimization system control power management and monitoring of operation health for PEM fuel cells along with main physics in PEM fuel cells for physics-informed machine learning. The objective of this review is three fold: (1) to present the most recent status of PEM fuel cell applications in the portable stationary and transportation sectors; (2) to describe the important fundamentals for the further advancement of fuel cell technology in terms of design and control optimization cost reduction and durability improvement; and (3) to explain machine learning physics-informed deep learning and AI methods and describe their significant potentials in PEM fuel cell research and development (R&D).
Prospectivity Analysis for Underground Hydrogen Storage, Taranaki Basin, Aotearoa New Zealand: A Multi-criteria Decision-making Approach
May 2024
Publication
Seasonal underground hydrogen storage (UHS) in porous media provides an as yet untested method for storing surplus renewable energy and balancing our energy demands. This study investigates the technical suitability for UHS in depleted hydrocarbon fields and one deep aquifer site in Taranaki Basin Aotearoa New Zealand. Prospective sites are assessed using a decision tree approach providing a “fast-track” method for identifying potential sites and a decision matrix approach for ranking optimal sites. Based on expert elicitation the most important factors to consider are storage capacity reservoir depth and parameters that affect hydrogen injectivity/withdrawal and containment. Results from both approaches suggest that Paleogene reservoirs from gas (or gas cap) fields provide the best option for demonstrating UHS in Aotearoa New Zealand and that the country’s projected 2050 hydrogen storage demand could be exceeded by developing one or two high ranking sites. Lower priority is assigned to heterolithic and typically finer grained labile and clay-rich Miocene oil reservoirs and to deep aquifers that have no proven hydrocarbon containment.
THyGA - Roadmap H2NG for Europe
May 2023
Publication
This report aims at summarizing the different stakeholders’ opinions on H2NG blends and cross them with the THyGA results to recommend some necessary actions to prepare the field for operational large-scale blending (liability delayed ignition adjustment…).
Hydrogen Refuelling Station Calibration with a Traceable Gravimetric Standard
Apr 2020
Publication
Of all the alternatives to hydrocarbon fuels hydrogen offers the greatest long-term potential to radically reduce the many problems inherent in fuel used for transportation. Hydrogen vehicles have zero tailpipe emissions and are very efficient. If the hydrogen is made from renewable sources such as nuclear power or fossil sources with carbon emissions captured and sequestered hydrogen use on a global scale would produce almost zero greenhouse gas emissions and greatly reduce air pollutant emissions. The aim of this work is to realise a traceability chain for hydrogen flow metering in the range typical for fuelling applications in a wide pressure range with pressures up to 875 bar (for Hydrogen Refuelling Station - HRS with Nominal Working Pressure of 700 bar) and temperature changes from −40 °C (pre-cooling) to 85 °C (maximum allowed vehicle tank temperature) in accordance with the worldwide accepted standard SAE J2601. Several HRS have been tested in Europe (France Netherlands and Germany) and the results show a good repeatability for all tests. This demonstrates that the testing equipment works well in real conditions. Depending on the installation configuration some systematic errors have been detected and explained. Errors observed for Configuration 1 stations can be explained by pressure differences at the beginning and end of fueling in the piping between the Coriolis Flow Meter (CFM) and the dispenser: the longer the distance the bigger the errors. For Configuration 2 where this distance is very short the error is negligible.
Comparative Analysis of Direct Operating Costs: Conventional vs. Hydrogen Fuel Cell 19-Seat Aircraft
Jul 2023
Publication
In this paper a comparative analysis of direct operating costs between a 19-seat conventional and hydrogen-powered fuel cell aircraft is performed by developing a model to estimate direct operating costs and considering the evolution of costs over time from 2030 to 2050. However due to the technology being in its early stages of development and implementation there are still considerable uncertainties surrounding the direct operating costs of hydrogen aircraft. To address this the study considers high and low kerosene growth rates and optimistic and pessimistic development scenarios for hydrogen fuel cell aircraft while also considering the evolution of costs over time. The comparative analysis uses real flight and aircraft data for the airliner Trade Air. The results show that the use of 19-seat hydrogen fuel cell aircraft for air transportation is a viable option when compared to conventional aircraft. Additionally the study suggests potential policies and other measures that could accelerate the adoption of hydrogen fuel cell technology by considering their direct operating costs.
Massive Green Hydrogen Production Using Solar and Wind Energy: Comparison between Europe and the Middle East
Jul 2023
Publication
This comparative study examines the potential for green hydrogen production in Europe and the Middle East leveraging 3MWp solar and wind power plants. Experimental weather data from 2022 inform the selection of two representative cities namely Krakow Poland (Europe) and Diyala Iraq (Middle East). These cities are chosen as industrial–residential zones representing the respective regions’ characteristics. The research optimizes an alkaline water electrolyzer capacity in juxtaposition with the aforementioned power plants to maximize the green hydrogen output. Economic and environmental factors integral to green hydrogen production are assessed to identify the region offering the most advantageous conditions. The analysis reveals that the Middle East holds superior potential for green hydrogen production compared to Europe attributed to a higher prevalence of solar and wind resources coupled with reduced land and labor costs. Hydrogen production costs in Europe are found to range between USD 9.88 and USD 14.31 per kilogram in contrast to the Middle East where costs span from USD 6.54 to USD 12.66 per kilogram. Consequently the Middle East emerges as a more feasible region for green hydrogen production with the potential to curtail emissions enhance air quality and bolster energy security. The research findings highlight the advantages of the Middle East industrial–residential zone ‘Diyala’ and Europe industrial–residential zone ‘Krakow’ in terms of their potential for green hydrogen production.
On the Cost of Zero Carbon Hydrogen: A Techno-economic Analysis of Steam Methane Reforming with Carbon Capture and Storage
May 2023
Publication
This article challenges the view that zero carbon hydrogen from steam methane reforming (SMR) is prohibitively expensive and that the cost of CO2 capture increases exponentially as residual emissions approach zero; a flawed narrative often eliminating SMR produced hydrogen as a route to net zero. We show that the capture and geological storage of 100% of the fossil CO2 produced in a SMR is achievable with commercially available post-combustion capture technology and an open art solvent. The Levelised Cost of Hydrogen (LCOH) of 69£/MWhth HHV (2.7£/kg) for UK production remains competitive to other forms of low carbon hydrogen but retains a hydrogen lifecycle carbon intensity of 5 gCO2e/MJ (LHV) due to natural gas supply chain and embodied greenhouse gas (GHG) emissions. Compensating for the remaining lifecycle GHG emissions via Direct Air Capture with geological CO2 Storage (DACCS) increases the LCOH to 71–86 £/MWhth HHV (+3–25%) for a cost estimate of 100–1000 £/tCO2 for DACCS and the 2022 UK natural gas supply chain methane emission rates. Finally we put in perspective the cost of CO2 avoidance of fuel switching from natural gas to hydrogen with long term price estimates for natural gas use and DACCS and hydrogen produced from electrolysis.
Magnesium-Based Hydrogen Storage Alloys: Advances, Strategies, and Future Outlook for Clean Energy Applications
May 2024
Publication
Magnesium-based hydrogen storage alloys have attracted significant attention as promising materials for solid-state hydrogen storage due to their high hydrogen storage capacity abundant reserves low cost and reversibility. However the widespread application of these alloys is hindered by several challenges including slow hydrogen absorption/desorption kinetics high thermodynamic stability of magnesium hydride and limited cycle life. This comprehensive review provides an in-depth overview of the recent advances in magnesium-based hydrogen storage alloys covering their fundamental properties synthesis methods modification strategies hydrogen storage performance and potential applications. The review discusses the thermodynamic and kinetic properties of magnesium-based alloys as well as the effects of alloying nanostructuring and surface modification on their hydrogen storage performance. The hydrogen absorption/desorption properties of different magnesium-based alloy systems are compared and the influence of various modification strategies on these properties is examined. The review also explores the potential applications of magnesium-based hydrogen storage alloys including mobile and stationary hydrogen storage rechargeable batteries and thermal energy storage. Finally the current challenges and future research directions in this field are discussed highlighting the need for fundamental understanding of hydrogen storage mechanisms development of novel alloy compositions optimization of modification strategies integration of magnesium-based alloys into hydrogen storage systems and collaboration between academia and industry.
PEM Water Electrolysis for Hydrogen Production: Fundamentals, Advances, and Prospects
Jun 2022
Publication
Hydrogen as a clean energy carrier is of great potential to be an alternative fuel in the future. Proton exchange membrane (PEM) water electrolysis is hailed as the most desired technology for high purity hydrogen production and self-consistent with volatility of renewable energies has ignited much attention in the past decades based on the high current density greater energy efficiency small mass-volume characteristic easy handling and maintenance. To date substantial efforts have been devoted to the development of advanced electrocatalysts to improve electrolytic efficiency and reduce the cost of PEM electrolyser. In this review we firstly compare the alkaline water electrolysis (AWE) solid oxide electrolysis (SOE) and PEM water electrolysis and highlight the advantages of PEM water electrolysis. Furthermore we summarize the recent progress in PEM water electrolysis including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts in the acidic electrolyte. We also introduce other PEM cell components (including membrane electrode assembly current collector and bipolar plate). Finally the current challenges and an outlook for the future development of PEM water electrolysis technology for application in future hydrogen production are provided.
Spatial Succession for Degradation of Solid Multicomponent Food Waste and Purification of Toxic Leachate with the Obtaining of Biohydrogen and Biomethane
Jan 2022
Publication
A huge amount of organic waste is generated annually around the globe. The main sources of solid and liquid organic waste are municipalities and canning and food industries. Most of it is disposed of in an environmentally unfriendly way since none of the modern recycling technologies can cope with such immense volumes of waste. Microbiological and biotechnological approaches are extremely promising for solving this environmental problem. Moreover organic waste can serve as the substrate to obtain alternative energy such as biohydrogen (H2 ) and biomethane (CH4 ). This work aimed to design and test new technology for the degradation of food waste coupled with biohydrogen and biomethane production as well as liquid organic leachate purification. The effective treatment of waste was achieved due to the application of the specific granular microbial preparation. Microbiological and physicochemical methods were used to measure the fermentation parameters. As a result a four-module direct flow installation efficiently couples spatial succession of anaerobic and aerobic bacteria with other micro- and macroorganisms to simultaneously recycle organic waste remediate the resulting leachate and generate biogas.
Modelling Hydrogen Storage and Filling Systems: A Dynamic and Customizable Toolkit
Aug 2023
Publication
Hydrogen plays a vital role in decarbonizing the mobility sector. With the number of hydrogen vehicles expected to drastically increase a network of refuelling stations needs to be built to keep up with the hydrogen demand. However further research and development on hydrogen refuelling infrastructure storage and standardization is required to overcome technical and economic barriers. Simulation tools can reduce time and costs during the design phase but existing models do not fully support calculations of complete and arbitrary system layouts. Therefore a flexible simulation toolbox for rapid investigations of hydrogen refuelling and extraction processes as well as development of refuelling infrastructure vehicle tank systems and refuelling protocols for non-standardized applications was developed. Our model library H2VPATT comprises of typical components found in refuelling infrastructure. The key component is the hydrogen tank model. The simulation model was successfully validated with measurement data from refuelling tests of a 320 l type III tank.
Energy Management Strategy Based on Reinforcement Learning and Frequency Decoupling for Fuel Cell Hybrid Powertrain
Apr 2024
Publication
This study presents a Two-Layer Deep Deterministic Policy Gradient (TL-DDPG) energy management strategy for Hydrogen fuel cell hybrid train that aims to solve the problem that traditional reinforcement learning strategies require high initial values and are difficult to optimize global variables. Augmenting the optimization capabilities of the inner layer a frequency decoupling algorithm integrates into the outer layer furnishing a fitting initial value for strategy optimization. This addition aims to bolster the stability of fuel cell output thereby enhancing the overall efficiency of the hybrid power system. In comparison with the traditional reinforcement learning algorithm the proposed approach demonstrates notable improvements: a reduction in hydrogen consumption per 100 km by 16.3 kg a 9.7% increase in the output power stability of the fuel cell and a 1.8% enhancement in its efficiency.
Thermodynamic Evaluation and Carbon Footprint Analysis of the Application of Hydrogen-Based Energy-Storage Systems in Residential Buildings
Sep 2016
Publication
This study represents a thermodynamic evaluation and carbon footprint analysis of the application of hydrogen based energy storage systems in residential buildings. In the system model buildings are equipped with photovoltaic (PV) modules and a hydrogen storage system to conserve excess PV electricity from times with high solar irradiation to times with low solar irradiation. Short-term storages enable a degree of self-sufficiency of approximately 60% for a single-family house (SFH) [multifamily house (MFH): 38%]. Emissions can be reduced by 40% (SFH) (MFH: 30%) compared to households without PV modules. These results are almost independent of the applied storage technology. For seasonal storage the degree of self-sufficiency ranges between 57 and 83% (SFH). The emission reductions highly depend on the storage technology as emissions caused by manufacturing the storage dominate the emission balance. Compressed gas or liquid organic hydrogen carriers are the best options enabling emission reductions of 40%.
The Role of Hydrogen for a Greenhouse Gas-neutral Germany by 2045
May 2023
Publication
This paper aims to provide a holistic analysis of the role of hydrogen for achieving greenhouse gas neutrality in Germany. For that purpose we apply an integrated energy system model which includes all demand sectors of the German energy system and optimizes the transformation pathway from today's energy system to a future cost-optimal energy system. We show that 412 TWh of hydrogen are needed in the year 2045 mostly in the industry and transport sector. Particularly the use of about 267 TWh of hydrogen in industry is essential as there are no cost-effective alternatives for the required emission reduction in the chemical industry or in steel production. Furthermore we illustrate that the German hydrogen supply in the year 2045 requires both an expansion of domestic electrolyzer capacity to 71 GWH2 and hydrogen imports from other European countries and Northern Africa of about 196 TWh. Moreover flexible operation of electrolyzers is cost-optimal and crucial for balancing the intermittent nature of volatile renewable energy sources. Additionally a conducted sensitivity analysis shows that full domestic hydrogen supply in Germany is possible but requires an electrolyzer capacity of 111 GWH2.
Hydrogen Gas Compression for Efficient Storage: Balancing Energy and Increasing Density
May 2024
Publication
This article analyzes the processes of compressing hydrogen in the gaseous state an aspect considered important due to its contribution to the greater diffusion of hydrogen in both the civil and industrial sectors. This article begins by providing a concise overview and comparison of diverse hydrogen-storage methodologies laying the groundwork with an in-depth analysis of hydrogen’s thermophysical properties. It scrutinizes plausible configurations for hydrogen compression aiming to strike a delicate balance between energy consumption derived from the fuel itself and the requisite number of compression stages. Notably to render hydrogen storage competitive in terms of volume pressures of at least 350 bar are deemed essential albeit at an energy cost amounting to approximately 10% of the fuel’s calorific value. Multi-stage compression emerges as a crucial strategy not solely for energy efficiency but also to curtail temperature rises with an upper limit set at 200 ◦C. This nuanced approach is underlined by the exploration of compression levels commonly cited in the literature particularly 350 bar and 700 bar. The study advocates for a three-stage compression system as a pragmatic compromise capable of achieving high-pressure solutions while keeping compression work below 10 MJ/kg a threshold indicative of sustainable energy utilization.
Perspectives for a Sustainable Implementation of Super-green Hydrogen Production by Photoelectrochemical Technology in Hard-to-abate Sectors
May 2023
Publication
The energy transition's success hinges on the effectiveness to curbing carbon emissions from hard-to-abate sectors. Hydrogen (H2) has been proposed as the candidate vector that could be used to replace fossils in such energy-intensive industries. Despite green H2 via solar-powered water electrolysis being a reality today the overall defossilization of the hard-to-abate sectors by electrolytic H2 would be unfeasible as it relies on the availability of renewable electricity. In this sense the unbiassed photoelectrochemical water splitting (PEC) as inspired by natural photosynthesis may be a promising alternative expected in the long term. PEC could be partly or even completely decoupled from renewable electricity and then could produce H2 autonomously. However some remaining challenges still limit PEC water splitting to operate sustainably. These limitations need to be evaluated before the scaling up and implementation. A prospective life cycle assessment (LCA) has been used to elucidate a positive performance scenario in which the so-called super-green H2 or photo-H2 could be a sustainable alternative to electro-H2. The study has defined future scenarios by conducting a set of sensitivity assessments determining the figures of operating parameters such as i) the energy to produce the cell; ii) solar-to-hydrogen efficiency (STH); and iii) lifetime. These parameters have been evaluated based on two impact categories: i) Global Warming Potential (GWP); and ii) fossil Abiotic Depletion Potentials (fADP). The mature water electrolysis was used for benchmarking in order to elucidate the target performance in which PEC technology could be positively implemented at large-scale. Efficiencies over 10% (STH) and 7 years of lifetime are compulsory in the coming developments to achieve a positive scaling-up.
The Hydrogen Storage Challenge: Does Storage Method and Size Affect the Cost and Operational Flexbility of Hydrogen Supply Chains?
Jun 2023
Publication
Hydrogen is seen as a key energy vector in future energy systems due to its ability to be stored in large volumes for long periods providing energy flexibility and security. Despite the importance of storage in hydrogen's potential role in a zero-carbon energy system many techno-economic analyses fail to adequately model different storage methods in hydrogen supply chains often ignoring storage requirements altogether. Therefore this paper uses a data-driven techno-economic analysis (TEA) tool to examine the effect of storage size and cost on three different 2030 hydrogen supply chain scenarios: wind-based solar-based and mixed-source grid electrolysis. For varying storage sizes and specific capital costs the overall levelised cost of hydrogen (LCOH) including production storage and delivery to a constant demand varies significantly. The LCOH ranges from V3.90 e12.40/kgH2 V5.50e12.75/kgH2 and V2.80e15.65/kgH2 for the wind-based solar-based and mixed-source grid scenarios respectively with lower values for scenarios with low-cost storage. This highlights the critical role of low-cost hydrogen storage in realising the energy flexibility and security electrolytic hydrogen can provide.
Techno-Economic Potential of Wind-Based Green Hydrogen Production in Djibouti: Literature Review and Case Studies
Aug 2023
Publication
Disputed supply chains inappropriate weather and low investment followed by the Russian invasion of Ukraine has led to a phenomenal energy crisis especially in the Horn of Africa. Accordingly proposing eco-friendly and sustainable solutions to diversify the access of electricity in the Republic of Djibouti which has no conventional energy resources and is completely energy dependent on its neighboring countries has become a must. Therefore the implementation of sustainable renewable and energy storage systems is nationally prioritized. This paper deals for the first time with the exploitation of such an affordable and carbon-free resource to produce hydrogen from wind energy in the rural areas of Nagad and Bara Wein in Djibouti. The production of hydrogen and the relevant CO2 emission reduction using different De Wind D6 Vestas and Nordex wind turbines are displayed while using Alkaline and Proton Exchange Membrane (PEM) electrolyzers. The Bara Wein and Nagad sites had a monthly wind speed above 7 m/s. From the results the Nordex turbine accompanied with the alkaline electrolyzer provides the most affordable electricity production approximately 0.0032 $/kWh for both sites; this cost is about one per hundred the actual imported hydroelectric energy price. Through the ecological analysis the Nordex turbine is the most suitable wind turbine with a CO2 emission reduction of 363.58 tons for Bara Wein compared to 228.76 tons for Nagad. While integrating the initial cost of wind turbine implementation in the capital investment the mass and the levelized cost of the produced green hydrogen are estimated as (29.68 tons and 11.48 $/kg) for Bara Wein with corresponding values of (18.68 tons and 18.25 $/kg) for Nagad.
Investigations on Pressure Dependence of Coriolis Mass Flow Meters Used at Hydrogen Refueling Stations
Sep 2020
Publication
In the framework of the ongoing EMPIR JRP 16ENG01 ‘‘Metrology for Hydrogen Vehicles’’ a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min−1) and pressures (up to 87.5 MPa).
Biological Hydrogen Methanation with Carbon Dioxide Utilization: Methanation Acting as Mediator in the Hydrogen Economy
May 2023
Publication
Hydrogen is one of the main energy carriers playing a prominent role in the future decarbonization of the economy. However several aspects regarding the transport and storage of this gas are challenging. The intermediary conversion of hydrogen into high-density energy molecules may be a crucial step until technological conditions are ready to attain a significant reduction in fossil fuel use in transport and the industrial sector. The process of transforming hydrogen into methane by anaerobic digestion is reviewed showing that this technology is a feasible option for facilitating hydrogen storage and transport. The manuscript focuses on the role of anaerobic digestion as a technology driver capable of fast adaptation to current energy needs. The use of thermophilic systems and reactors capable of increasing the contact between the H2 -fuel and liquid phase demonstrated outstanding capabilities attaining higher conversion rates and increasing methane productivity. Pressure is a relevant factor of the process allowing for better hydrogen solubility and setting the basis for considering feasible underground hydrogen storage concomitant with biological methanation. This feature may allow the integration of sequestered carbon dioxide as a relevant substrate.
Review on Ammonia as a Potential Fuel: From Synthesis to Economics
Feb 2021
Publication
Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.
Toward Sustainability: An Overview of the Use of Green Hydrogen in the Agriculture and Livestock Sector
Aug 2023
Publication
The agro-livestock sector produces about one third of global greenhouse gas (GHG) emissions. Since more energy is needed to meet the growing demand for food and the industrial revolution in agriculture renewable energy sources could improve access to energy resources and energy security reduce dependence on fossil fuels and reduce GHG emissions. Hydrogen production is a promising energy technology but its deployment in the global energy system is lagging. Here we analyzed the theoretical and practical application of green hydrogen generated by electrolysis of water powered by renewable energy sources in the agro-livestock sector. Green hydrogen is at an early stage of development in most applications and barriers to its large-scale deployment remain. Appropriate policies and financial incentives could make it a profitable technology for the future.
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