- Home
- A-Z Publications
- Publications
Publications
Porosity and Thickness Effect of Pd–Cu–Si Metallic Glasses on Electrocatalytic Hydrogen Production and Storage
Aug 2021
Publication
This contribution places emphasis on tuning pore architecture and film thickness of mesoporous Pd–Cu–Si thin films sputtered on Si/SiO2 substrates for enhanced electrocatalytic and hydrogen sorption/desorption activity and their comparison with the state-of-the-art thin film electrocatalysts. Small Tafel slope of 43 mV dec–1 for 1250 nm thick coatings with 2 µm diameter pores with 4.2 µm interspacing (H2) electrocatalyst with comparable hydrogen overpotentials to the literature suggests its use for standard fuel cells. The largest hydrogen sorption has been attained for the 250 nm thick electrocatalyst on 5 µm pore diameter and 12 µm interspacing (2189 µC cm–2 per CV cycle) making it possible for rapid storage systems. Moreover the charge transfer resistance described by an equivalent circuit model has an excellent correlation with Tafel slopes. Along with its very low Tafel slope of 42 mV dec–1 10 nm thick H2 pore design electrocatalyst has the highest capacitive response of ∼0.001 S sn cm–2 and is promising to be used as a nano-charger and hydrogen sensor.
Flammability Reduction in a Pressurised Water Electrolyser Based on a Thin Polymer Electrolyte Membrane through a Pt-alloy Catalytic Approach
Jan 2019
Publication
Various Pt-based materials (unsupported Pt PtRu PtCo) were investigated as catalysts for recombining hydrogen and oxygen back into water. The recombination performance correlated well with the surface Pt metallic state. Alloying cobalt to platinum was observed to produce an electron transfer favouring the occurrence of a large fraction of the Pt metallic state on the catalyst surface. Unsupported PtCo showed both excellent recombination performance and dynamic behaviour. In a packed bed catalytic reactor when hydrogen was fed at 4% vol. in the oxygen stream (flammability limit) 99.5% of the total H2 content was immediately converted to water in the presence of PtCo thus avoiding safety issues. The PtCo catalyst was thus integrated in the anode of the membrane-electrode assembly of a polymer electrolyte membrane electrolysis cell. This catalyst showed good capability to reduce the concentration of hydrogen in the oxygen stream under differential pressure operation (1–20 bar) in the presence of a thin (90 μm) Aquivion® membrane. The modified system showed lower hydrogen concentration in the oxygen flow than electrolysis cells based on state-of-the-art thick polymer electrolyte membranes and allowed to expand the minimum current density load down to 0.15 A cm−2 . This was mainly due to the electrochemical oxidation of permeated H2 to protons that were transported back to the cathode. The electrolysis cell equipped with a dual layer PtCo/IrRuOx oxidation catalyst achieved a high operating current density (3 A cm−2 ) as requested to decrease the system capital costs under high efficiency conditions (about 77% efficiency at 55 °C and 20 bar). Moreover the electrolysis system showed reduced probability to reach the flammability limit under both high differential pressure (20 bar) and partial load operation (5%) as needed to properly address grid-balancing service
Thermodynamic Analysis of Hydrogen Production via Chemical Looping Steam Methane Reforming Coupled with In Situ CO2 Capture
Dec 2014
Publication
A detailed thermodynamic analysis of the sorption enhanced chemical looping reforming of methane (SE-CL-SMR) using CaO and NiO as CO2 sorbent and oxygen transfer material (OTM) respectively was conducted. Conventional reforming (SMR) and sorption enhanced reforming (SE-SMR) were also investigated for comparison reasons. The results of the thermodynamic analysis show that there are significant advantages of both sorption enhanced processes compared to conventional reforming. The presence of CaO leads to higher methane conversion and hydrogen purity at low temperatures. Addition of the OTM in the SECL-SMR process concept minimizes the thermal requirements and results in superior performance compared to SE-SMR and SMR in a two-reactor concept with use of pure oxygen as oxidant/sweep gas.
Risk-adjusted Preferences of Utility Companies and Institutional Investors for Battery Storage and Green Hydrogen Investment
Feb 2022
Publication
Achieving climate-neutrality requires considerable investment in energy storage systems (ESS) to integrate variable renewable energy sources into the grid. However investments into ESS are often unprofitable in particular for grid-scale battery storage and green hydrogen technologies prompting many actors to call for policy intervention. This study investigates investor-specific risk-return preferences for ESS investment and derives policy recommendations. Insights are drawn from 1605 experimental investment-related decisions obtained from 42 high-level institutional investors and utility representatives. Results reveal that both investor groups view revenue stacking as key to making ESS investment viable. While the expected return on investment is the most important project characteristic risk-return preferences for other features diverge between groups. Institutional investors appear more open to exploring new technological ventures (20% of utility respondents would not consider making investments into solar photovoltaic-hydrogen) whereas utilities seem to prefer greenfield projects (23% of surveyed institutional investors rejected such projects). Interestingly both groups show strong aversion towards energy market price risk. Institutional investors require a premium of 6.87 percentage points and utilities 5.54 percentage points for moving from a position of fully hedged against market price risk to a scenario where only 20% of revenue is fixed underlining the need for policy support.
Experimental Study on Tri-fuel Combustion Using Premixed Methane-hydrogen Mixtures Ignited by a Diesel Pilot
Apr 2021
Publication
A comprehensive investigation on diesel pilot spray ignited methane-hydrogen (CH4–H2) combustion tri-fuel combustion (TF) is performed in a single-cylinder compression ignition (CI) engine. The experiments provide a detailed analysis of the effect of H2 concentration (based on mole fraction MH2) and charge-air temperature (Tair) on the ignition behavior combustion stability cycle-to-cycle (CCV) and engine performance. The results indicate that adding H2 from 0 to 60% shortens the ignition delay time (IDT) and combustion duration (based on CA90) up to 33% and 45% respectively. Thereby H2 helps to increase the indicated thermal efficiency (ITE) by as much as 10%. Furthermore to gain an insight into the combustion stability and CCV the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) methodologies are applied to estimate the combustion stability and CCV of the TF combustion process. The results reveal that the pressure oscillation can be reduced up to 4 dB/Hz and the CCV by 50% when MH2 < 60% and Tair < 55 °C. However when MH2 > 60% and Tair > 40 °C abnormal combustion and knocking are observed.
Fuel Cells and Hydrogen Observatory Standards Report
Sep 2021
Publication
Purpose: The Standards module of the FCHO presents a large number of standards relevant for the deployment of hydrogen and fuel cells. The standards are categorized in order to enhance ease of access and usability. The development of sector-relevant standards facilitates and enhances economies of scale interoperability comparability safety and many other issues. Scope: The database presents European and International standards. Standards from the following standards developing organizations are included: CEN CENELEC ISO IEC OIML. The report spans January 2019 – December 2019. Key Findings: The development of sector relevant standards on an international level continued to grow in 2019 on European level many standards are still in the process of being drafted. The recently established CEN-CLC JTC 6 (Hydrogen in energy systems) has not published standards yet but is working on drafting standards on for example Guarantees of Origin.
Recent Advances in Carbon Dioxide Conversion: A Circular Bioeconomy Perspective
Jun 2021
Publication
Managing the concentration of atmospheric CO2 requires a multifaceted engineering strategy which remains a highly challenging task. Reducing atmospheric CO2 (CO2R) by converting it to value-added chemicals in a carbon neutral footprint manner must be the ultimate goal. The latest progress in CO2R through either abiotic (artificial catalysts) or biotic (natural enzymes) processes is reviewed herein. Abiotic CO2R can be conducted in the aqueous phase that usually leads to the formation of a mixture of CO formic acid and hydrogen. By contrast a wide spectrum of hydrocarbon species is often observed by abiotic CO2R in the gaseous phase. On the other hand biotic CO2R is often conducted in the aqueous phase and a wide spectrum of value-added chemicals are obtained. Key to the success of the abiotic process is understanding the surface chemistry of catalysts which significantly governs the reactivity and selectivity of CO2R. However in biotic CO2R operation conditions and reactor design are crucial to reaching a neutral carbon footprint. Future research needs to look toward neutral or even negative carbon footprint CO2R processes. Having a deep insight into the scientific and technological aspect of both abiotic and biotic CO2R would advance in designing efficient catalysts and microalgae farming systems. Integrating the abiotic and biotic CO2R such as microbial fuel cells further diversifies the spectrum of CO2R.
Hydrogen Production in Methane Decomposition Reactor Using Solar Thermal Energy
Nov 2021
Publication
This study investigates the decomposition of methane using solar thermal energy as a heat source. Instead of the direct thermal decomposition of the methane at a temperature of 1200 ◦C or higher a catalyst coated with carbon black on a metal foam was used to lower the temperature and activation energy required for the reaction and to increase the yield. To supply solar heat during the reaction a reactor suitable for a solar concentrating system was developed. In this process a direct heating type reactor with quartz was initially applied and a number of problems were identified. An indirect heating type reactor with an insulated cavity and a rotating part was subsequently developed followed by a thermal barrier coating application. Methane decomposition experiments were conducted in a 40 kW solar furnace at the Korea Institute of Energy Research. Conversion rates of 96.7% and 82.6% were achieved when the methane flow rate was 20 L/min and 40 L/min respectively.
Hydrogen for Net Zero - A Critical Cost-competitive Energy Vector
Nov 2021
Publication
The report “Hydrogen for Net Zero” presents an ambitious yet realistic deployment scenario until 2030 and 2050 to achieve Net Zero emissions considering the uses of hydrogen in industry power mobility and buildings. The scenario is described in terms of hydrogen demand supply infrastructure abatement potential and investments required and then compared with current momentum and investments in the industry to identify the investment gaps across value chains and geographies.
The report is based on the technoeconomic data of cost and performance of hydrogen technologies provided by Hydrogen Council members and McKinsey & Company as well as the Hydrogen Council investment tracker which covers all large-scale investments into hydrogen globally.
Link to their website
The report is based on the technoeconomic data of cost and performance of hydrogen technologies provided by Hydrogen Council members and McKinsey & Company as well as the Hydrogen Council investment tracker which covers all large-scale investments into hydrogen globally.
Link to their website
Analysing Future Demand, Supply, and Transport of Hydrogen
Jun 2021
Publication
Hydrogen is crucial to Europe’s transformation into a climate-neutral continent by mid-century. This study concludes that the European Union (EU) and UK could see a hydrogen demand of 2300 TWh (2150-2750 TWh) by 2050. This corresponds to 20-25% of EU and UK final energy consumption by 2050. Achieving this future role of hydrogen depends on many factors including market frameworks legislation technology readiness and consumer choice.
The document can be download on their website
The document can be download on their website
A Perspective on Hydrogen Investment, Deployment and Cost Competitiveness
Feb 2021
Publication
Deployment and investments in hydrogen have accelerated rapidly in response to government commitments to deep decarbonisation establishing hydrogen as a key component in the energy transition.
To help guide regulators decision-makers and investors the Hydrogen Council collaborated with McKinsey & Company to release the report ‘Hydrogen Insights 2021: A Perspective on Hydrogen Investment Deployment and Cost Competitiveness’. The report offers a comprehensive perspective on market deployment around the world investment momentum as well as implications on cost competitiveness of hydrogen solutions.
The document can be downloaded from their website
To help guide regulators decision-makers and investors the Hydrogen Council collaborated with McKinsey & Company to release the report ‘Hydrogen Insights 2021: A Perspective on Hydrogen Investment Deployment and Cost Competitiveness’. The report offers a comprehensive perspective on market deployment around the world investment momentum as well as implications on cost competitiveness of hydrogen solutions.
The document can be downloaded from their website
Fatigue Crack Growth in Operated Gas Pipeline Steels
Jun 2020
Publication
Regularities of fatigue crack growth for pipeline steels of different strength are presented and the changes in fatigue behavior of these steels after long term operation are analyzed. Threshold values of stress intensity factor range are lower for operated steels comparing to the corresponding values for as received ones. During the testing in the simulated soil solution NS4 a barely noticeable tendency to increase the threshold values of SIF was traced. It was explained by the appearance of intergranular fracture elements on the backgrownd of the typical flat fatigue relief already in the near-threshold region of fatigue crack growth curves in the soil solution. A higher relief of intergranular facets provided favorable conditions for occurrence of crack closure effect.<br/>Fatigue testing was performed using steel specimens after in-laboratory and in-service degradation and it was shown that results for both degraded steels are very close to each other proving the validity of the method of in-laboratory degradation. A new methodic approach to fatigue testing of pipe steels is presented which allows simulating working conditions of gas pipelines namely the hydrogen diffusion through the pipe wall to its external surface and estimating its possible effect on SCC. It consists in evaluation of the influence of hydrogen reached the crack tip only due to its diffusion on the crack growth. It is found that hydrogen absorbed by metal during the test providing such conditions causes a leap of crack growth rate in the Paris region of the fatigue crack growth curve of the tested 17H1S steel. Intergranular mechanism of fracture detected on the specimen fracture surface is suggested as a clear evidence of embrittlement of grain boundaries as a result of its hydrogenation.
A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium—Palladium Nanoparticles
Jun 2021
Publication
The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition reaching conversion to 81%. The reported process could potentially be used in commercial applications.
Effect of Hydrogen and Strain-Induced Martensite on Mechanical Properties of AISI 304 Stainless Steel
Jul 2016
Publication
Plastic deformation and strain-induced martensite (SIM α′) transformation in metastable austenitic AISI 304 stainless steel were investigated through room temperature tensile tests at strain rates ranging from 2 × 10−6 to 2 × 10−2/s. The amount of SIM was measured on the fractured tensile specimens using a feritscope and magnetic force microscope. Elongation to fracture tensile strength hardness and the amount of SIM increased with decreasing the strain rate. The strain-rate dependence of RT tensile properties was observed to be related to the amount of SIM. Specifically SIM formed during tensile tests was beneficial in increasing the elongation to fracture hardness and tensile strength. Hydrogen suppressed the SIM formation leading to hydrogen softening and localized brittle fracture.
Optimal Scheduling of Multi-energy Type Virtual Energy Storage System in Reconfigurable Distribution Networks for Congestion Management
Jan 2023
Publication
The virtual energy storage system (VESS) is one of the emerging novel concepts among current energy storage systems (ESSs) due to the high effectiveness and reliability. In fact VESS could store surplus energy and inject the energy during the shortages at high power with larger capacities compared to the conventional ESSs in smart grids. This study investigates the optimal operation of a multi-carrier VESS including batteries thermal energy storage (TES) systems power to hydrogen (P2H) and hydrogen to power (H2P) technologies in hydrogen storage systems (HSS) and electric vehicles (EVs) in dynamic ESS. Further demand response program (DRP) for electrical and thermal loads has been considered as a tool of VESS due to the similar behavior of physical ESS. In the market three participants have considered such as electrical thermal and hydrogen markets. In addition the price uncertainties were calculated by means of scenarios as in stochastic programming while the optimization process and the operational constraints were considered to calculate the operational costs in different ESSs. However congestion in the power systems is often occurred due to the extreme load increments. Hence this study proposes a bi-level formulation system where independent system operators (ISO) manage the congestion in the upper level while VESS operators deal with the financial goals in the lower level. Moreover four case studies have considered to observe the effectiveness of each storage system and the simulation was modeled in the IEEE 33-bus system with CPLEX in GAMS.
A Model for Hydrogen Detonation Diffraction or Transmission to a Non-confined Layer
Sep 2021
Publication
One strategy for arresting propagating detonation waves in pipes is by imposing a sudden area enlargement which provides a rapid lateral divergence of the gases in the reaction zone and attenuates the leading shock. For sufficiently small tube diameter the detonation decays to a deflagration and the shock decays to negligible strengths. This is known as the critical tube diameter problem. In the present study we provide a closed form model to predict the detonation quenching for 2D channels. This problem also applies to the transmission of a detonation wave from a confined layer to a weakly-confined layer. Whitham’s geometric shock dynamics coupled with a shock evolution law based on shocks sustained by a constant source obtained by the shock change equations of Radulescu is shown to capture the lateral shock dynamics response to the failure wave originating at the expansion corner. A criterion for successful detonation transmission to open space is that the lateral strain rate provided by the failure wave not exceed the critical strain rate of steady curved detonations. Using the critical lateral strain rate obtained by He and Clavin a closed form solution is obtained for the critical channel opening permitting detonation transmission. The predicted critical channel width is found in excellent agreement with our recent experiments and simulations of diffracting H2/O2/Ar detonations. Model comparison with available data for H2/air detonation diffraction into open space at ambient conditions or for transmission into a weakly confined layer by air is also found in good agreement within a factor never exceeding 2 for the critical opening or layer dimension.
Hydrogen Fuel Cell Vehicles; Current Status and Future Prospect
Jun 2019
Publication
The hazardous effects of pollutants from conventional fuel vehicles have caused the scientific world to move towards environmentally friendly energy sources. Though we have various renewable energy sources the perfect one to use as an energy source for vehicles is hydrogen. Like electricity hydrogen is an energy carrier that has the ability to deliver incredible amounts of energy. Onboard hydrogen storage in vehicles is an important factor that should be considered when designing fuel cell vehicles. In this study a recent development in hydrogen fuel cell engines is reviewed to scrutinize the feasibility of using hydrogen as a major fuel in transportation systems. A fuel cell is an electrochemical device that can produce electricity by allowing chemical gases and oxidants as reactants. With anodes and electrolytes the fuel cell splits the cation and the anion in the reactant to produce electricity. Fuel cells use reactants which are not harmful to the environment and produce water as a product of the chemical reaction. As hydrogen is one of the most efficient energy carriers the fuel cell can produce direct current (DC) power to run the electric car. By integrating a hydrogen fuel cell with batteries and the control system with strategies one can produce a sustainable hybrid car
Hydrogen Storage Using a Hot Pressure Swing Reactor
Jun 2017
Publication
Our contribution demonstrates that hydrogen storage in stationary Liquid Organic Hydrogen Carrier (LOHC) systems becomes much simpler and significantly more efficient if both the LOHC hydrogenation and the LOHC dehydrogenation reaction are carried out in the same reactor using the same catalyst. The finding that the typical dehydrogenation catalyst for hydrogen release from perhydro dibenzyltoluene (H18-DBT) Pt on alumina turns into a highly active and very selective dibenzyltoluene hydrogenation catalyst at temperatures above 220 °C paves the way for our new hydrogen storage concept. Herein hydrogenation of H0-DBT and dehydrogenation of H18-DBT is carried out at the same elevated temperature between 290 and 310 °C with hydrogen pressure being the only variable for shifting the equilibrium between hydrogen loading and release. We demonstrate that the heat of hydrogenation can be provided at a temperature level suitable for effective dehydrogenation catalysis. Combined with a heat storage device of appropriate capacity or a high pressure steam system this heat could be used for dehydrogenation.
Phase Field Modelling of Formation and Fracture of Expanding Precipitates
May 2017
Publication
It is a common belief that embedded expanding inclusions are subjected to an internal homogeneous compressive hydrostatic stress. Still cracks that appear in precipitates that occupy a larger volume than the original material are frequently observed. The appearance of cracks has since long been regarded as a paradox. In the present study it is shown that matrix materials that increases its volume even several percent during the precipitation process develop a tensile hydrostatic stress in the centre of the precipitate. This is the result of a complicated mechanical-chemical phase transformation process. The process is here studied using a Landau phase feld model. Before the material is transformed and incorporated in a precipitate it undergoes stretching beyond the elastic strain limit because of the presence of already expanded material. During the phase transformation the accompanying volumetric expansion cannot be fully accommodated which instead creates an internal compressive stress and adds tension in the surrounding material. As the growth of the precipitate proceeds a region with increasing tensile stress develops in the interior of the precipitate. This is suggested to be the most probable cause of the observed cracks. First the mechanics that lead to the tension is computed. The infuence of elastic-plastic properties is studied both for cases both with and without cracks. The growth history from microscopic to macroscopic precipitates is followed and the result is compared with observations of so called hydride blisters that are formed on surfaces of zirconium alloys in the presence of hydrogen. A common practical situation is when the zirconium is in contact with an object of lower temperature. Then the cooled spot attracts hydrogen that make the zirconium transform to a metal hydride with the shape of a blister. The simulations predicts a final size and position of the growing crack that compares well with the experimental observations.
A Mountain to Climb? Tracking Progress in Scaling Up Renewable Gas Production in Europe
Oct 2019
Publication
In the last couple of years there has been increasing recognition by key players in the European gas industry that to mitigate the risk of terminal decline in the context of a decarbonising energy system there will need to be rapid scale up of decarbonised gas. This has led to several projections of the scale of decarbonised gas which could potentially be supplied by 2030 2040 or 2050. This paper joint with the Sustainable Gas Institute at Imperial College London considers the very significant rate of scale up and the significant cost reductions contemplated by such projections. Based on a database of actual announced projects (both committed and in earlier stages of development) for production of decarbonised gas it then considers the extent to which project activity is consistent with meeting the ambitious projections. It identifies a significant gap in current levels of activity largely because there is not yet sufficient economic incentive for investors to develop the required projects. It is intended that this paper will form the basis of continued tracking of the level of activity over the coming years to help inform industry players of further actions which may be required.
Energy Transition in France
May 2022
Publication
To address the climate emergency France is committed to achieving carbon neutrality by 2050. It plans to significantly increase the contribution of renewable energy in its energy mix. The share of renewable energy in its electricity production which amounts to 25.5% in 2020 should reach at least 40% in 2030. This growth poses several new challenges that require policy makers and regulators to act on the technological changes and expanding need for flexibility in power systems. This document presents the main strategies and projects developed in France as well as various recommendations to accompany and support its energy transition policy.
Platinum Single-atom Catalyst Coupled with Transition Metal/Metal Oxide Heterostructure for Accelerating Alkaline Hydrogen Evolution Reaction
Jun 2021
Publication
Single-atom catalysts provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However the sluggish activity of the catalysts for alkaline water dissociation has hampered advances in highly efficient hydrogen production. Herein we develop a single-atom platinum immobilized NiO/Ni heterostructure (PtSA-NiO/Ni) as an alkaline hydrogen evolution catalyst. It is found that Pt single atom coupled with NiO/Ni heterostructure enables the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*) which efficiently tailors the water dissociation energy and promotes the H* conversion for accelerating alkaline hydrogen evolution reaction. A further enhancement is achieved by constructing PtSA-NiO/Ni nanosheets on Ag nanowires to form a hierarchical three-dimensional morphology. Consequently the fabricated PtSA-NiO/Ni catalyst displays high alkaline hydrogen evolution performances with a quite high mass activity of 20.6 A mg−1 for Pt at the overpotential of 100 mV significantly outperforming the reported catalysts.
Techno-economic Analysis of Hydrogen Enhanced Methanol to Gasoline Process from Biomass-derived Synthesis Gas
Mar 2021
Publication
In this paper the implications of the use of hydrogen on product yield and conversion efficiency as well as on economic performance of a hydrogen enhanced Biomass-to-Liquid (BtL) process are analyzed. A process concept for the synthesis of fuel (gasoline and LPG) from biomass-derived synthesis gas via Methanol-to-Gasoline (MtG) route with utilization of carbon dioxide from gasification by feeding additional hydrogen is developed and modeled in Aspen Plus. The modeled process produces 0.36 kg fuel per kg dry straw. Additionally 99 MW electrical power are recovered from purge and off gases from fuel synthesis in CCGT process covering the electricity consumption of fuel synthesis and synthesis gas generation. The hydrogen enhanced BtL procces reaches a combined chemical and electrical efficiency of 48.2% and overall carbon efficiency of 69.5%. The total product costs (TPC) sum up to 3.24 €/kg fuel. Raw materials (hydrogen and straw) make up the largest fraction of TPC with a total share of 75%. The hydrogen enhanced BtL process shows increased chemical energy and carbon efficiencies and thus higher product yields. However economic analysis shows that the process is unprofitable under current conditions due to high costs for hydrogen provision.
Nickel-Based Electrocatalysts for Water Electrolysis
Feb 2022
Publication
Currently hydrogen production is based on the reforming process leading to the emission of pollutants; therefore a substitute production method is imminently required. Water electrolysis is an ideal alternative for large-scale hydrogen production as it does not produce any carbon-based pollutant byproducts. The production of green hydrogen from water electrolysis using intermittent sources (e.g. solar and eolic sources) would facilitate clean energy storage. However the electrocatalysts currently required for water electrolysis are noble metals making this potential option expensive and inaccessible for industrial applications. Therefore there is a need to develop electrocatalysts based on earth-abundant and low-cost metals. Nickel-based electrocatalysts are a fitting alternative because they are economically accessible. Extensive research has focused on developing nickel-based electrocatalysts for hydrogen and oxygen evolution. Theoretical and experimental work have addressed the elucidation of these electrochemical processes and the role of heteroatoms structure and morphology. Even though some works tend to be contradictory they have lit up the path for the development of efficient nickel-based electrocatalysts. For these reasons a review of recent progress is presented herein.
Combined Soft Templating with Thermal Exfoliation Toward Synthesis of Porous g-C3N4 Nanosheets for Improved Photocatalytic Hydrogen Evolution
Apr 2021
Publication
Insufficient active sites and fast charge carrier recombination are detrimental to photocatalytic activity of graphitic carbon nitride (g-C3N4). In this work a combination of pore creating with thermal exfoliation was employed to prepare porous g-C3N4 nanosheets for photocatalytic water splitting into hydrogen. Hexadecyl trimethyl ammonium chloride (CTAC) as the soft template promoted the formation of porous g-C3N4 during the thermal condensation of melamine. On further post-synthesis calcination the porous g-C3N4 aggregates were exfoliated into discrete nanosheets accompanied by an increase in specific surface area and defects. Optimal porous g-C3N4 nanosheets achieved 3.6 times the photocatalytic hydrogen evolution rate for bulk counterpart. The enhanced photocatalytic activity may be ascribed to TCN-1%CTAC has larger specific surface area stronger optical absorption intensity and higher photogenerated electron–hole separation efficiency. The external quantum efficiency of TCN-1%CTAC was measured to be 3.4% at 420 nm. This work provides a simple combinatorial strategy for the preparation of porous g-C3N4 nanosheets with low cost environmental friendliness and enhanced photocatalytic activity.
Green Hydrogen: A Guide to Policy Making
Nov 2020
Publication
Hydrogen produced with renewable energy sources – or “green” hydrogen – has emerged as a key element to achieve net-zero emissions from heavy industry and transport. Along with net-zero commitments by growing numbers of governments green hydrogen has started gaining momentum based on low-cost renewable electricity ongoing technological improvements and the benefits of greater power-system flexibility.
Hydrogen-based fuels previously attracted interest mainly as an alternative to shore up oil supply. However green hydrogen as opposed to the “grey” (fossil-based) or “blue” (hybrid) varieties also help to boost renewables in the energy mix and decarbonise energy-intensive industries.
This report from the International Renewable Energy Agency (IRENA) outlines the main barriers that inhibiting green hydrogen uptake and the policies needed to address these. It also offers insights on how to kickstart the green hydrogen sector as a key enabler of the energy transition at the national or regional level.
Key pillars of green hydrogen policy making include:
Hydrogen-based fuels previously attracted interest mainly as an alternative to shore up oil supply. However green hydrogen as opposed to the “grey” (fossil-based) or “blue” (hybrid) varieties also help to boost renewables in the energy mix and decarbonise energy-intensive industries.
This report from the International Renewable Energy Agency (IRENA) outlines the main barriers that inhibiting green hydrogen uptake and the policies needed to address these. It also offers insights on how to kickstart the green hydrogen sector as a key enabler of the energy transition at the national or regional level.
Key pillars of green hydrogen policy making include:
- National hydrogen strategy. Each country needs to define its level of ambition for hydrogen outline the amount of support required and provide a reference on hydrogen development for private investment and finance.
- Setting policy priorities. Green hydrogen can support a wide range of end-uses. Policy makers should identify and focus on applications that provide the highest value.
- Guarantees of origin. Carbon emissions should be reflected over the whole lifecycle of hydrogen. Origin schemes need to include clear labels for hydrogen and hydrogen products to increase consumer awareness and facilitate claims of incentives.
- Governance system and enabling policies. As green hydrogen becomes mainstream policies should cover its integration into the broader energy system. Civil society and industry must be involved to maximise the benefits.
- Subsequent briefs will explore the entire hydrogen value chain providing sector-by-sector guidance on the design and implementation of green hydrogen policies.
Hydrogen-Rich Gas Production from Two-Stage Catalytic Pyrolysis of Pine Sawdust with Nano-NiO/Al2O3 Catalyst
Feb 2022
Publication
Hydrogen production from biomass pyrolysis is economically and technologically attractive from the perspectives of energy and the environment. The two-stage catalytic pyrolysis of pine sawdust for hydrogen-rich gas production is investigated using nano-NiO/Al2O3 as the catalyst at high temperatures. The influences of residence time (0–30 s) and catalytic temperature (500–800 ◦C) on pyrolysis performance are examined in the distribution of pyrolysis products gas composition and gas properties. The results show that increasing the residence time decreased the solid and liquid products but increased gas products. Longer residence times could promote tar cracking and gas-phase conversion reactions and improve the syngas yield H2/CO ratio and carbon conversion. The nano-NiO/A12O3 exhibits excellent catalytic activity for tar removal with a tar conversion rate of 93% at 800 ◦C. The high catalytic temperature could significantly improve H2 and CO yields by enhancing the decomposition of tar and gas-phase reactions between CO2 and CH4 . The increasing catalytic temperature increases the dry gas yield and carbon conversion but decreases the H2/CO ratio and low heating value.
Recent Advances in Pd-Based Membranes for Membrane Reactors
Jan 2017
Publication
Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys supports deposition/production techniques etc. High flux and cheap membranes yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly when employing the membranes in fluidized bed reactors the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes resistance to hydrogen embrittlement and stability at high temperature.
Anchoring of Turbulent Premixed Hydrogen/Air Flames at Externally Heated Walls
Oct 2020
Publication
A joint experimental and numerical investigation of turbulent flame anchoring at externally heated walls is presented. The phenomenon has primarily been studied for laminar flames and micro-combustion while this study focuses on large-scale applications and elevated Reynolds number flows. Therefore a novel burner design is developed and examined for a diverse set of operating conditions. Hydroxyl radical chemiluminescence measurements are employed to validate the numerical method. The numerical investigation evaluates the performance of various hydrogen/air kinetics Reynolds-averaged turbulence models and the eddy dissipation concept (EDC) as a turbulence-chemistry interaction model. Simulation results show minor differences between detailed chemical mechanisms but pronounced deviations for a reduced kinetic. The baseline k-ω turbulence model is assessed to most accurately predict flame front position and shape. Universal applicability of EDC modelling constants is contradicted. Conclusively the flame anchoring concept is considered a promising approach for pilot flames in continuous combustion devices.
Water Photo-Oxidation Reaction on Clean and Doped Two-Dimensional Graphitic C2N
Apr 2020
Publication
In the search for new efficient photo-catalysts for hydrogen production through water splitting the main attention has been paid to tuning the band gap width and its position with respect to vacuum level. However actual electro-catalytic activity for the water oxidation reaction on a catalyst surface is no less important than those quantities. In this work we evaluate from first principles the thermodynamics of the reaction on relatively new candidates for water splitting: two-dimensional C2N and that doped with phosphorus. We find that the 4-step reaction usually expected for water splitting will not proceed on these systems resulting in oxygen atoms left strongly adsorbed to the surface. Another option a 3-step reaction is also found to be unfavorable. We also test an effect of higher oxygen coverage on the reaction thermodynamics as suggested elsewhere. We find that indeed the doubled O-coverage makes the 4-step reaction feasible for the doped C2N. However an unacceptably high anode potential is required to make this reaction proceed. We thus conclude that the materials under consideration may not be efficient electro-catalysts for water splitting.
Indentation and Hydride Orientation in Zr-2.5%Nb Pressure Tube Material
Jun 2019
Publication
In this study indentations were made on Zr-2.5%Nb pressure tube material to induce multi-axial stress field. An I-shaped punch mark was indented on the Pressure tube material with predefined punch load. Later material was charged with 50 wppm of hydrogen. The samples near the punch mark were metallographically examined for hydrides orientation. It was observed that hydrides exhibited preferentially circumferential orientation far away from the indent to mixed orientation containing both circumferential and radial hydrides near the indent. This is probably as a result of stress field generated by indentation. Extent of radial hydride formation was observed to be varying with indentation load.
A Review on Recent Advances in Hydrogen Energy, Fuel Cell, Biofuel and Fuel Refining via Ultrasound Process Intensification
Mar 2021
Publication
Hydrogen energy is one of the most suitable green substitutes for harmful fossil fuels and has been investigated widely. This review extensively compiles and compares various methodologies used in the production storage and usage of hydrogen. Sonochemistry is an emerging synthesis process and intensification technique adapted for the synthesis of novel materials. It manifests acoustic cavitation phenomena caused by ultrasound where higher rates of reactions occur locally. The review discusses the effectiveness of sonochemical routes in developing fuel cell catalysts fuel refining biofuel production chemical processes for hydrogen production and the physical chemical and electrochemical hydrogen storage techniques. The operational parameters and environmental conditions used during ultrasonication also influence the production rates which have been elucidated in detail. Hence this review's major focus addresses sonochemical methods that can contribute to the technical challenges involved in hydrogen usage for energy.
HyDeploy Report: Material Effects of Introducing Hydrogen into the UK Gas Supply
Jun 2018
Publication
Introduction of hydrogen into the UK gas main has been reviewed in terms of how materials within the Keele G3 gas distribution network (G3 GDN) on the Keele University network may be affected by contact with natural gas (NG):hydrogen blends up to a limit of 20 % mol/mol hydrogen.<br/>This work has formed part of the supporting evidence for a 1 year hydrogen blending trial on the Keele G3 GDN coordinated by the HyDeploy consortium (formed of representatives of Cadent Northern Gas Networks ITM Power Progressive Energy HSL and Keele University).<br/>A wide range of materials were identified and assessed via a combination of literature review and practical test programmes. No significant changes to material properties in terms of accelerated material degradation or predicted efficiency of gas confinement were identified which would cause concern for the year-long trial at Keele.<br/>It can be concluded that materials on the Keele G3 GDN should be acceptable to provide a safe operating network the HyDeploy demonstrator project up to a level of 20 % mol/mol hydrogen.<br/>Check the supplements tab for the other documents in this report
Suitable Site Selection for Solar‐Based Green Hydrogen in Southern Thailand Using GIS‐MCDM Approach
May 2022
Publication
Climate change mitigation efforts are in dire need of greener and more versatile fuel al‐ ternatives to fossil fuels. Green hydrogen being both renewable and flexible has the potential to offset fossil fuels as the primary fuel source. Countries around the world are planning to develop their green hydrogen industries and accurate potential assessment is vital. This study employed the consolidation of a geographic information system (GIS) and the analytical hierarchy process (AHP) technique of multicriteria decision making (MCDM) for the potential assessment of green hydrogen in southern Thailand through the selection of suitable sites for solar‐based green hy‐ drogen production. Technical economic and environmental criteria with 10 sub‐criteria were con‐ sidered for the selection of suitable sites. With 0.243 (24.3%) weight the distance from protected areas turned out to be the most important sub‐criterion whereas the criterion of elevation with a 0.017 (1.7%) score was considered the least important. Southern Thailand is a well‐suited area for solar‐based green hydrogen production with a 4302 km2 area of high suitability and a 3350 km2 area of moderate suitability. These suitable areas can be utilized to develop the green hydrogen industry of Thailand and the method developed can be employed for the assessment of green hydrogen potential in other parts of the country. Studies like these are vital for the development of green hydrogen road maps for Thailand to develop its hydrogen policy and promote investments in the sector.
Mg-based Materials for Hydrogen Storage
Aug 2021
Publication
Over the last decade’s magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as well as their extraordinary high gravimetric and volumetric storage densities. This review work provides a broad overview of the most appealing systems and of their hydrogenation/dehydrogenation properties. Special emphasis is placed on reviewing the efforts made by the scientific community in improving the material’s thermodynamic and kinetic properties while maintaining a high hydrogen storage capacity.
Hydrous Hydrazine Decomposition for Hydrogen Production Using of Ir/CeO2: Effect of Reaction Parameters on the Activity
May 2021
Publication
In the present work an Ir/CeO2 catalyst was prepared by the deposition–precipitation method and tested in the decomposition of hydrazine hydrate to hydrogen which is very important in the development of hydrogen storage materials for fuel cells. The catalyst was characterised using different techniques i.e. X-ray photoelectron spectroscopy (XPS) transmission electron microscopy (TEM) scanning electron microscopy (SEM) equipped with X-ray detector (EDX) and inductively coupled plasma—mass spectroscopy (ICP-MS). The effect of reaction conditions on the activity and selectivity of the material was evaluated in this study modifying parameters such as temperature the mass of the catalyst stirring speed and concentration of base in order to find the optimal conditions of reaction which allow performing the test in a kinetically limited regime.
Investigation of Structure of AlN Thin Films Using Fourier-transform Infrared Spectroscopy
Feb 2020
Publication
This study focuses on structural imperfections caused by hydrogen impurities in AlN thin films obtained using atomic layer deposition method (ALD). Currently there is a severe lack of studies regarding the presence of hydrogen in the bulk of AlN films. Fourier-transform infrared spectroscopy (FTIR) is one of the few methods that allow detection bonds of light elements in particular - hydrogen. Hydrogen is known to be a frequent contaminant in AlN films grown by ALD method it may form different bonds with nitrogen e.g. amino (–NH2) or imide (–NH) groups which impair the quality of the resulting film. Which is why it is important to investigate the phenomenon of hydrogen as well as to search for the suitable methods to eliminate or at least reduce its quantity. In this work several samples have been prepared using different precursors substrates and deposition parameters and characterized using FTIR and additional techniques such as AFM XPS and EDS to provide a comparative and comprehensive analysis of topography morphology and chemical composition of AlN thin films.
Hydrogeochemical Modeling to Identify Potential Risks of Underground Hydrogen Storage in Depleted Gas Fields
Nov 2018
Publication
Underground hydrogen storage is a potential way to balance seasonal fluctuations in energy production from renewable energies. The risks of hydrogen storage in depleted gas fields include the conversion of hydrogen to CH4(g) and H2S(g) due to microbial activity gas–water–rock interactions in the reservoir and cap rock which are connected with porosity changes and the loss of aqueous hydrogen by diffusion through the cap rock brine. These risks lead to loss of hydrogen and thus to a loss of energy. A hydrogeochemical modeling approach is developed to analyze these risks and to understand the basic hydrogeochemical mechanisms of hydrogen storage over storage times at the reservoir scale. The one-dimensional diffusive mass transport model is based on equilibrium reactions for gas–water–rock interactions and kinetic reactions for sulfate reduction and methanogenesis. The modeling code is PHREEQC (pH-REdox-EQuilibrium written in the C programming language). The parameters that influence the hydrogen loss are identified. Crucial parameters are the amount of available electron acceptors the storage time and the kinetic rate constants. Hydrogen storage causes a slight decrease in porosity of the reservoir rock. Loss of aqueous hydrogen by diffusion is minimal. A wide range of conditions for optimized hydrogen storage in depleted gas fields is identified.
A Comprehensive Review on the Recent Development of Ammonia as a Renewable Energy Carrier
Jun 2021
Publication
Global energy sources are being transformed from hydrocarbon-based energy sources to renewable and carbon-free energy sources such as wind solar and hydrogen. The biggest challenge with hydrogen as a renewable energy carrier is the storage and delivery system’s complexity. Therefore other media such as ammonia for indirect storage are now being considered. Research has shown that at reasonable pressures ammonia is easily contained as a liquid. In this form energy density is approximately half of that of gasoline and ten times more than batteries. Ammonia can provide effective storage of renewable energy through its existing storage and distribution network. In this article we aimed to analyse the previous studies and the current research on the preparation of ammonia as a next-generation renewable energy carrier. The study focuses on technical advances emerging in ammonia synthesis technologies such as photocatalysis electrocatalysis and plasmacatalysis. Ammonia is now also strongly regarded as fuel in the transport industrial and power sectors and is relatively more versatile in reducing CO2 emissions. Therefore the utilisation of ammonia as a renewable energy carrier plays a significant role in reducing GHG emissions. Finally the simplicity of ammonia processing transport and use makes it an appealing choice for the link between the development of renewable energy and demand.
Thermodynamic Modeling of Hydrogen Refueling for Heavy-duty Fuel Cell Buses and Comparison with Aggregated Real Data
Apr 2021
Publication
The foreseen uptake of hydrogen mobility is a fundamental step towards the decarbonization of the transport sector. Under such premises both refuelling infrastructure and vehicles should be deployed together with improved refuelling protocols. Several studies focus on refuelling the light-duty vehicles with 10 kgH2 up to 700 bar however less known effort is reported for refuelling heavy-duty vehicles with 30–40 kgH2 at 350 bar. The present study illustrates the application of a lumped model to a fuel cell bus tank-to-tank refuelling event tailored upon the real data acquired in the 3Emotion Project. The evolution of the main refuelling quantities such as pressure temperature and mass flow are predicted dynamically throughout the refuelling process as a function of the operating parameters within the safety limits imposed by SAE J2601/2 technical standard. The results show to refuel the vehicle tank from half to full capacity with an Average Pressure Ramp Rate (APRR) equal to 0.03 MPa/s are needed about 10 min. Furthermore it is found that the effect of varying the initial vehicle tank pressure is more significant than changing the ambient temperature on the refuelling performances. In conclusion the analysis of the effect of different APRR from 0.03 to 0.1 MPa/s indicate that is possible to safely reduce the duration of half-to-full refuelling by 62% increasing the APRR value from 0.03 to 0.08 MPa/s.
Feature of Stress Corrosion Cracking of Degraded Gas Pipeline Steels
Aug 2019
Publication
Stress corrosion cracking (SCC) of steels can reduce the structural integrity of gas pipelines. To simulate in-service degradation of pipeline steels in laboratory the method of accelerated degradation consisted in subjecting specimens to electrolytic hydrogenation to loading up the certain plastic deformation and heating of specimen at 250°C was recently developed. The purpose of this paper was to analyse mechanical and SCC behaviour of in-service and in-laboratory degraded gas pipeline steels and to reveal some fractographic features of SCC. Three pipeline steels of the different strength (17H1S which is equivalent of API X52 API X60 and API X70) were investigated. The characteristics of the as-received pipeline steels with different strength were compared with the properties of pipeline steels after in-service and in-laboratory degradation. An influence of the NS4 solution on SCC resistance of 17H1S and API X60 steels in the as-received state and after the accelerated degradation using slow strain rate tension method was analysed. The noticeable decrease of plasticity for 17H1S and API X60 steels after long-term operation was shown. Deep microdelaminations revealed in the central part of fracture surfaces for the operated steels can be considered as the signs of dissipated damaging in the metal caused by texture and hydrogen absorbed by metal. Comparison of the SCC tests results showed that the characteristics of both steels in the as-received state were insignificantly changed under the influence of the environment. At the same time the degraded steels were characterized by a high sensitivity to SCC. It was shown fractographically that it associated with cracking along interfaces of ferrite and pearlite grains with secondary deep intergranular cracks formation and also by delamination between ferrite and cementite inside pearlite grains. The similar fracture mechanism at SCC tests was revealed for near the outer surface of the specimens and in the central part of the fracture surfaces of in-laboratory degraded specimens. These results demonstrated the key role of hydrogen during SCC and in-bulk cracking as well.
Unconventional Pearlitic Pseudocolonies Affecting Macro-, Micro- and Nano-structural Integrity of Cold-drawn Pearlitic Steel Wires: Resembling van Gogh, Bernini, Mantegna and Picasso
Dec 2020
Publication
Prestressing steel wires are manufactured by cold drawing during which a preferential orientation is achieved in the matter of pearlitic colonies and lamellae. In addition to this general trend special (unconventional) pearlitic pseudocolonies evolve during the heavy-drawing manufacture process affecting the posterior macro- micro- and nano-structural integrity of the material. This paper discusses the important role of such a special microstructural unit (the pearlitic pseudocolony) in the fracture process in air (inert) environment in the presence of crack-like defects as well as in the case of environmentally assisted cracking (stress corrosion cracking by localized anodic dissolution) or hydrogen embrittlement. Results clearly demonstrate the key role of pearlitic pseudocolonies in promoting crack deflection (and thus mixed-mode propagation) after a global mode I cracking especially in the case of fracture in air and stress corrosion cracking.
The Microstructure Study of the Hydrogenated Titanium Specimens Tested at High Temperature Creep for Long-term Tensile Strength
Feb 2020
Publication
Experimental tests of flat titanium samples at a temperature of 450 °C stretched with a constant force up to destruction were carried out. Titanium samples were hydrogenated in the Moscow Aviation Institute laboratory to a hydrogen content of 0.1 % 0.3 % and 0.6 % by weight of the specimen and then tested in the laboratory of Lomonosov Moscow State University. From the experiments the time to failure the localization time of the deformations and the stress distribution along the longitudinal coordinate of the sample over time were obtained. A metallographic study was conducted and the phase composition was investigated in Moscow Aviation Institute. The effect of hydrogen on long-term strength mechanical characteristics and phase composition has been elucidated.
Novel Biofuel Cell Using Hydrogen Generation of Photosynthesis
Nov 2020
Publication
Energies based on biomaterials attract a lot of interest as next-generation energy because biomaterials are environmentally friendly materials and abundant in nature. Fuel cells are also known as the clean and important next-generation source of energy. In the present study to develop the fuel cell based on biomaterials a novel biofuel cell which consists of collagen electrolyte and the hydrogen fuel generated from photochemical system II (PSII) in photosynthesis has been fabricated and its property has been investigated. It was found that the PSII solution in which PSII was extracted from the thylakoid membrane using a surfactant generates hydrogen by the irradiation of light. The typical hydrogen-generating rate is approximately 7.41 × 1014 molecules/s for the light intensity of 0.5 mW/cm2 for the PSII solution of 5 mL. The biofuel cell using the PSII solution as the fuel exhibited approximately 0.12 mW/cm2 . This result indicates that the fuel cell using the collagen electrolyte and the hydrogen fuel generated from PSII solution becomes the new type of biofuel cell and will lead to the development of the next-generation energy
Energy Transition Outlook 2021: Technology Progress Report
Jun 2021
Publication
This report is part of DNV’s suite of Energy Transition Outlook publications for 2021. It focuses on how key energy transition technologies will develop compete and interact in the coming five years.
Debate and uncertainty about the energy transition tend to focus on what technology can and can’t do. All too often such discussions involve wishful thinking advocacy of a favoured technology or reference to outdated information. Through this report we bring insights derived from our daily work with the world’s leading energy players including producers transporters and end users. Each of the ten chapters that follow are written by our experts in the field – or in the case of maritime technologies on the ocean.
Because the pace of the transition is intensifying describing any given technology is like painting a fast-moving train. We have attempted to strike a balance between technical details and issues of safety efficiency cost and competitiveness. Transition technologies are deeply interlinked and in some cases interdependent; any discussion on green hydrogen for example must account for developments in renewable electricity hydrogen storage and transport systems and end-use technologies such as fuels cells.
Our selection of ten technologies is not exhaustive but each of these technologies is of particular interest for the pace and direction of the energy transition. They range from relatively mature technologies like solar PV to technologies like nuclear fusion which are some distance from commercialization but which have current R&D and prototyping worth watching. Together they cover most but not all key sectors. We describe expected developments for the coming five years which to a large extent will determine how the energy transition unfolds through to mid-century. As such this Technology Progress report is an essential supplement to our main Energy Transition Outlook forecast.
Our aim is to make an objective and realistic assessment of the status of these technologies and evaluate how they contribute to the energy transition ahead. Attention to progress in these technologies will be critical for anyone concerned with energy.
Debate and uncertainty about the energy transition tend to focus on what technology can and can’t do. All too often such discussions involve wishful thinking advocacy of a favoured technology or reference to outdated information. Through this report we bring insights derived from our daily work with the world’s leading energy players including producers transporters and end users. Each of the ten chapters that follow are written by our experts in the field – or in the case of maritime technologies on the ocean.
Because the pace of the transition is intensifying describing any given technology is like painting a fast-moving train. We have attempted to strike a balance between technical details and issues of safety efficiency cost and competitiveness. Transition technologies are deeply interlinked and in some cases interdependent; any discussion on green hydrogen for example must account for developments in renewable electricity hydrogen storage and transport systems and end-use technologies such as fuels cells.
Our selection of ten technologies is not exhaustive but each of these technologies is of particular interest for the pace and direction of the energy transition. They range from relatively mature technologies like solar PV to technologies like nuclear fusion which are some distance from commercialization but which have current R&D and prototyping worth watching. Together they cover most but not all key sectors. We describe expected developments for the coming five years which to a large extent will determine how the energy transition unfolds through to mid-century. As such this Technology Progress report is an essential supplement to our main Energy Transition Outlook forecast.
Our aim is to make an objective and realistic assessment of the status of these technologies and evaluate how they contribute to the energy transition ahead. Attention to progress in these technologies will be critical for anyone concerned with energy.
Electronic Structure and d-Band Center Control Engineering over Ni-Doped CoP3 Nanowall Arrays for Boosting Hydrogen Production
Jun 2021
Publication
To address the challenge of highly efficient water splitting into H2 successful fabrication of novel porous three-dimensional Ni-doped CoP3 nanowall arrays on carbon cloth was realized resulting in an effective self-supported electrode for the electrocatalytic hydrogen-evolution reaction. The synthesized samples exhibit rough curly and porous structures which are beneficial for gaseous transfer and diffusion during the electrocatalytic process. As expected the obtained Ni-doped CoP3 nanowall arrays with a doping concentration of 7% exhibit the promoted electrocatalytic activity. The achieved overpotentials of 176 mV for the hydrogen-evolution reaction afford a current density of 100 mA cm−2 which indicates that electrocatalytic performance can be dramatically enhanced via Ni doping. The Ni-doped CoP3 electrocatalysts with increasing catalytic activity should have significant potential in the field of water splitting into H2. This study also opens an avenue for further enhancement of electrocatalytic performance through tuning of electronic structure and d-band center by doping.
Well to Wheel Analysis of Low Carbon Alternatives for Road Traffic
Sep 2015
Publication
Several alternative fuel–vehicle combinations are being considered for replacement of the internal combustion engine (ICE) vehicles to reduce greenhouse gas (GHG) emissions and the dependence on fossil fuels. The International Energy Agency has proposed the inclusion of low carbon alternatives such as electricity hydrogen and biofuels in the transport sector for reducing the GHG emissions and providing a sustainable future. This paper compares the use of these alternative fuels viz. electricity hydrogen and bio-ethanol in combination with battery electric vehicle (BEV) and fuel cell electric vehicle (FCEV) technologies on the basis of their overall efficiency and GHG emissions involved in the conversion of the primary energy source to the actual energy required at wheels through a well-to-wheel analysis. The source of energy for electricity production plays a major role in determining the overall efficiency and the GHG emissions of a BEV. Hence electricity production mix of Germany (60% fossil fuel energy) France (76% nuclear energy) Sweden and Austria (60 and 76% renewable energy respectively) the European Union mix (48% fossil fuel energy) and the United States of America (68% fossil fuel energy) are considered for the BEV analysis. In addition to the standard hydrogen based FCEVs CNG and bio-ethanol based FCEVs are analysed. The influence of a direct ethanol fuel cell (DEFC) on GHG emissions and overall chain efficiency is discussed. In addition to the standard sources of bio-ethanol (like sugarcane corn etc.) sources like wood waste and wheat straw are included in the analysis. The results of this study suggest that a BEV powered by an electricity production mix dominated by renewable energy and bio-ethanol based DEFC electric vehicles offer the best solution in terms of GHG emissions efficiency and fossil fuel dependency. Bio-ethanol as a fuel has the additional advantage to be implemented readily in ICE vehicles followed by advancements through reformer based FCEVs and DEFC electric vehicles. Although important this analysis does not include the health effects of the alternative vehicles. Bio-ethanol used in an ICE may lead to increased emission of acetaldehydes which however might not be the case if it is used in fuel cells.
Deep-Decarbonisation Pathways for UK Industry
Dec 2020
Publication
The Climate Change Committee (CCC) commissioned Element Energy to improve our evidence base on the potential of industrial deep-decarbonisation measures (fuel switching CCS/BECCS measures to reduce methane emissions) and develop pathways for their application. This report summarises the evidence and results of the work including:
- Evidence on the key constraints and costs for technology and infrastructure deployment
- The methodology and new Net Zero Industry Pathway (N-ZIP) model used to determine deep-decarbonisation pathways for UK industry (drawing on the evidence above)
- A set of pathways and wider sensitivities produced using the N-ZIP model which fed into the CCC’s Sixth Carbon Budget pathways
- Recommended actions and policy measures as informed by the study.
Towards the Rational Design of Stable Electrocatalysts for Green Hydrogen Production
Feb 2022
Publication
Now it is time to set up reliable water electrolysis stacks with active and robust electro‐ catalysts to produce green hydrogen. Compared with catalytic kinetics much less attention has been paid to catalyst stability and the weak understanding of the catalyst deactivation mechanism restricts the design of robust electrocatalysts. Herein we discuss the issues of catalysts’ stability evaluation and characterization and the degradation mechanism. The systematic understanding of the degradation mechanism would help us to formulate principles for the design of stable catalysts. Particularly we found that the dissolution rate for different 3d transition metals differed greatly: Fe dissolves 114 and 84 times faster than Co and Ni. Based on this trend we designed Fe@Ni and FeNi@Ni core‐shell structures to achieve excellent stability in a 1 A cm−2 current density as well as good catalytic activity at the same time
Spin Pinning Effect to Reconstructed Oxyhydroxide Layer on Ferromagnetic Oxides for Enhanced Water Oxidation
Jun 2021
Publication
Producing hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. With spin-dependent kinetics in OER to manipulate the spin ordering of ferromagnetic OER catalysts (e.g. by magnetization) can reduce the kinetic barrier. However most active OER catalysts are not ferromagnetic which makes the spin manipulation challenging. In this work we report a strategy with spin pinning effect to make the spins in paramagnetic oxyhydroxides more aligned for higher intrinsic OER activity. The spin pinning effect is established in oxideFM/oxyhydroxide interface which is realized by a controlled surface reconstruction of ferromagnetic oxides. Under spin pinning simple magnetization further increases the spin alignment and thus the OER activity which validates the spin effect in rate-limiting OER step. The spin polarization in OER highly relies on oxyl radicals (O∙) created by 1st dehydrogenation to reduce the barrier for subsequent O-O coupling.
Storable Energy Production from Wind over Water
Apr 2020
Publication
The current status of a project is described which aims to demonstrate the technical and economic feasibility of converting the vast wind energy available over the globe’s oceans and lakes into storable energy. To this end autonomous high-performance sailing ships are equipped with hydrokinetic turbines whose output is stored either in electric batteries or is fed into electrolysers to produce hydrogen which then is compressed and stored in tanks. In the present paper the previous analytical studies which showed the potential of this “energy ship concept” are summarized and progress on its hardware demonstration is reported involving the conversion of a model sailboat to autonomous operation. The paper concludes with a discussion of the potential of this concept to achieve the IPCC-mandated requirement of reducing the global CO2 emissions by about 45% by 2030 reaching net zero by 2050.
Fabrication of Highly Textured 2D SnSe Layers with Tunable Electronic Properties for Hydrogen Evolution
Jun 2021
Publication
Hydrogen is regarded to be one of the most promising renewable and clean energy sources. Finding a highly efficient and cost-effective catalyst to generate hydrogen via water splitting has become a research hotspot. Two-dimensional materials with exotic structural and electronic properties have been considered as economical alternatives. In this work 2D SnSe films with high quality of crystallinity were grown on a mica substrate via molecular beam epitaxy. The electronic property of the prepared SnSe thin films can be easily and accurately tuned in situ by three orders of magnitude through the controllable compensation of Sn atoms. The prepared film normally exhibited p-type conduction due to the deficiency of Sn in the film during its growth. First-principle calculations explained that Sn vacancies can introduce additional reactive sites for the hydrogen evolution reaction (HER) and enhance the HER performance by accelerating electron migration and promoting continuous hydrogen generation which was mirrored by the reduced Gibbs free energy by a factor of 2.3 as compared with the pure SnSe film. The results pave the way for synthesized 2D SnSe thin films in the applications of hydrogen production.
Site-Dependent Environmental Impacts of Industrial Hydrogen Production by Alkaline Water Electrolysis
Jun 2017
Publication
Industrial hydrogen production via alkaline water electrolysis (AEL) is a mature hydrogen production method. One argument in favor of AEL when supplied with renewable energy is its environmental superiority against conventional fossil-based hydrogen production. However today electricity from the national grid is widely utilized for industrial applications of AEL. Also the ban on asbestos membranes led to a change in performance patterns making a detailed assessment necessary. This study presents a comparative Life Cycle Assessment (LCA) using the GaBi software (version 6.115 thinkstep Leinfelden-Echterdingen Germany) revealing inventory data and environmental impacts for industrial hydrogen production by latest AELs (6 MW Zirfon membranes) in three different countries (Austria Germany and Spain) with corresponding grid mixes. The results confirm the dependence of most environmental effects from the operation phase and specifically the site-dependent electricity mix. Construction of system components and the replacement of cell stacks make a minor contribution. At present considering the three countries AEL can be operated in the most environmentally friendly fashion in Austria. Concerning the construction of AEL plants the materials nickel and polytetrafluoroethylene in particular used for cell manufacturing revealed significant contributions to the environmental burden.
Wittichenite Semiconductor of Cu3BiS3 Films for Efficient Hydrogen Evolution from Solar Driven Photoelectrochemical Water Splitting
Jun 2021
Publication
A highly efficient low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here we found that the Cu3BiS3 film-based photocathode meets the abovementioned requirements. The Cu3BiS3-based photocathode presents a remarkable onset potential over 0.9 VRHE with excellent photoelectrochemical current densities (~7 mA/cm2 under 0 VRHE) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu3BiS3-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm2 assisted by the BiVO4 photoanode. A tandem device of Cu3BiS3-BiVO4 with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately a 5 × 5 cm2 large Cu3BiS3-BiVO4 tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.
Analysis of the Environmental Degradation Effects on the Cables of “La Arena” Bridge (Spain)
Sep 2017
Publication
After nearly 25 years of service some of the wires of the tendons of “La Arena” bridge (Spain) started to exhibit the effects of environmental degradation processes. “La Arena” is cable-stayed bridge with 6 towers and a reference span between towers of about 100 meters. After a maintenance inspection of the bridge evidences of corrosion were detected in some of the galvanized wires of the cables. A more in-deep analysis of these wires revealed that many of them exhibited loss of section due to the corrosion process. In order to clarify the causes of this degradation event and to suggest some remedial actions an experimental program was designed. This program consisted of tensile and fatigue tests on some strand samples of the bridge together with a fractographic analysis of the fracture surfaces of the wires its galvanized layer thickness and some hydrogen measurements (hydrogen embrittlement could be another effect of the environmental degradation process).Once the type and extension of the flaws in the wires was characterized a structural integrity assessment of the strands was performed with the aim of quantifying the margins until failure and establishing some maintenance recommendations.
A Combined Chemical-Electrochemical Process to Capture CO2 and Produce Hydrogen and Electricity
Sep 2021
Publication
Several carbon sequestration technologies have been proposed to utilize carbon dioxide (CO2 ) to produce energy and chemical compounds. However feasible technologies have not been adopted due to the low efficiency conversion rate and high-energy requirements. Process intensification increases the process productivity and efficiency by combining chemical reactions and separation operations. In this work we present a model of a chemical-electrochemical cyclical process that can capture carbon dioxide as a bicarbonate salt. The proposed process also produces hydrogen and electrical energy. Carbon capture is enhanced by the reaction at the cathode that displaces the equilibrium into bicarbonate production. Literature data show that the cyclic process can produce stable operation for long times by preserving ionic balance using a suitable ionic membrane that regulates ionic flows between the two half-cells. Numerical simulations have validated the proof of concept. The proposed process could serve as a novel CO2 sequestration technology while producing electrical energy and hydrogen.
Development of a Pneumatic Actuated Low-pressure Direct Injection Gas Injector for Hydrogen-fueled Internal Combustion Engines
Dec 2022
Publication
Mixture formation is one of the greatest challenges for the development of robust and efficient hydrogen-fueled internal combustion engines. In many reviews and research papers authors pointed out that direct injection (DI) has noteworthy advantages over a port fuel injection (PFI) such as higher power output higher efficiency the possibility of mixture stratification to control NOx-formation and reduce heat losses and above all to mitigate combustion abnormalities such as back-firing and pre-ignitions. When considering pressurized gas tanks for on-vehicle hydrogen storage a low-pressure (LP) injection system is advantageous since the tank capacity can be better exploited accordingly. The low gas density upstream of the injector requires cross-sectional areas far larger than any other injectors for direct injection in today's gasoline or diesel engines. The injector design proposed in this work consists of a flat valve seat to enable the achievement of lifetime requirements in heavy-duty applications. The gas supply pressure is used as the energy source for the actuation of the valve plate by means of a pneumatic actuator. This article describes the design and the performed tests carried out to prove the concept readiness of the new LP-DI-injector.
EUA- Bringing Hydrogen Alive
Apr 2021
Publication
The UK is on course to become a global leader in hydrogen technology. Over £3bn is ready to be invested into hydrogen today. The pace of activity is rapid and the opportunities are vast.
Join us at our free to attend event where you will gain unique insights into how the Hydrogen industry is progressing together with exclusive access to future plans.
The dynamic and lively session will demonstrate the viability of hydrogen as a key component to achieve Net Zero.
Confirmed contributors include:
Join us at our free to attend event where you will gain unique insights into how the Hydrogen industry is progressing together with exclusive access to future plans.
The dynamic and lively session will demonstrate the viability of hydrogen as a key component to achieve Net Zero.
Confirmed contributors include:
- National Grid Gas Transmission
- Cadent
- Chris Train Previous CEO Cadent
- DNV
- Worcester Bosch
- ITM Power
- Northern Gas Networks
- Decarbonising Heat in Buildings - New Research Findings from the Gas Distribution Networks
On Flame Ball-to-Deflagration Transition in Hydrogen-air Mixtures
Sep 2021
Publication
Ultra-lean hydrogen-air combustion is characterized by two phenomena: the difference in upward and downward flame propagation concentration limits and the incomplete combustion. The clear answers on the two basic questions are still absent: What is a reason and what is a mechanism for their manifestation? Problem statement and the principal research topics of the Flame Ball to Deflagration Transition (FBDT) phenomenon in gaseous hydrogen-air mixtures are presented. The non-empirical concept of the fundamental concentration limits discriminates two basic low-speed laminar combustion patterns - self-propagating locally planar deflagration fronts and drifting locally spherical flame balls. To understand - at what critical conditions and how the baric deflagrations are transforming into iso- baric flame balls? - the photographic studies of the quasi-2-dim flames freely propagating outward radially via thin horizontal channel were performed. For gradual increase of initial hydrogen concentration from 3 to 12 vol.% the three representative morphological types of combustion (star-like dendrite-like and quasi-homogeneous) and two characteristic processes of reaction front bifurcation were revealed. Key elements of the FBDT mechanism both for 2-dim and 3-dim combustion are the following. Locally spherical ""leading centres"" (drifting flame balls) are the ""elementary building blocks"" of all ultra-lean flames. System of the drifting flame balls is formed due to primary bifurcation of the pre-flame kernel just after ignition. Subsequent mutual dynamics and overall morphology of the ultra-lean flames are governed by competitive non-local interactions of the individual drifting flame balls and their secondary/tertiary/etc. bifurcations defined by initial stoichiometry."
Calibrating a Ductile Damage Model for Two Pipeline Steels: Method and Challenges
Dec 2020
Publication
This work is part of a project that aims to develop a micromechanics based damage law taking into account hydrogen assisted degradation. A 'vintage' API 5L X56N and a 'modern' API 5L X70M pipeline steel have been selected for this purpose. The paper focuses on an experimental calibration of ductile damage properties of the well known complete Gurson model for the two steels in absence of hydrogen. A basic microstructural characterization is provided showing a banded ferrite-pearlite microstructure for both steels. Charpy impact tests showed splits at the fracture surface for the X70 steel. Double-notched round bar tensile tests are performed aiming to provide the appropriate input for damage model calibration. The double-notched nature of the specimens allows to examine the material state at maximum load in the unfailed notch and the final material state in the failed notch. Different notch radii are used capturing a broad range of positive stress triaxialities. The notches are optically monitored for transverse necking in two perpendicular directions (transverse to rolling and through thickness) to reveal any anisotropy in plastic deformation and/or damage. It is explained how the occurrence of splits at the segregation zone and anisotropy complicate the calibration procedure. Calibration is done for each steel and acceptable results are obtained. However the occurrence of splits did not allow to evaluate the damage model for the highest levels of tested stress triaxiality.
Enhancing the Hydrogen Storage Properties of AxBy Intermetallic Compounds by Partial Substitution: A Short Review
Dec 2020
Publication
Solid-state hydrogen storage covers a broad range of materials praised for their gravimetric volumetric and kinetic properties as well as for the safety they confer compared to gaseous or liquid hydrogen storage methods. Among them AxBy intermetallics show outstanding performances notably for stationary storage applications. Elemental substitution whether on the A or B site of these alloys allows the effective tailoring of key properties such as gravimetric density equilibrium pressure hysteresis and cyclic stability for instance. In this review we present a brief overview of partial substitution in several AxBy alloys from the long-established AB5 and AB2-types to the recently attractive and extensively studied AB and AB3 alloys including the largely documented solid-solution alloy systems. We not only present classical and pioneering investigations but also report recent developments for each AxBy category. Special care is brought to the influence of composition engineering on desorption equilibrium pressure and hydrogen storage capacity. A simple overview of the AxBy operating conditions is provided hence giving a sense of the range of possible applications whether for low- or high-pressure systems.
Life Cycle Assessment of Fuel Cell Vehicles Considering the Detailed Vehicle Components: Comparison and Scenario Analysis in China Based on Different Hydrogen Production Schemes
Aug 2019
Publication
Numerous studies concerning the life cycle assessment of fuel cell vehicles (FCVs) have been conducted. However little attention has been paid to the life cycle assessment of an FCV from the perspective of the detailed vehicle components. This work conducts the life cycle assessment of Toyota Mirai with all major components considered in a Chinese context. Both the vehicle cycle and the fuel cycle are included. Both comprehensive resources and energy consumption and comprehensive environmental emissions of the life cycles are investigated. Potential environmental impacts are further explored based on CML 2001 method. Then different hydrogen production schemes are compared to obtain the most favorable solution. To explore the potential of the electrolysis the scenario analysis of the power structure is conducted. The results show that the most mineral resources are consumed in the raw material acquisition stage the most fossil energy is consumed in the use stage and global warming potential (GWP) value is fairly high in all life cycle stages of Toyota Mirai using electrolyzed hydrogen. For hydrogen production schemes the scenario analysis indicates that simply by optimizing the power structure the environmental impact of the electrolysis remains higher than other schemes. When using the electricity from hydropower or wind power the best choice will be the electrolysis.
ZnO@ZIF-8 Core-Shell Structure Gas Sensors with Excellent Selectivity to H2
Jun 2021
Publication
As the energy crisis becomes worse hydrogen as a clean energy source is more and more widely used in industrial production and people’s daily life. However there are hidden dangers in hydrogen storage and transportation because of its flammable and explosive features. Gas detection is the key to solving this problem. High quality sensors with more practical and commercial value must be able to accurately detect target gases in the environment. Emerging porous metal-organic framework (MOF) materials can effectively improve the selectivity of sensors as a result of high surface area and coordinated pore structure. The application of MOFs for surface modification to improve the selectivity and sensitivity of metal oxides sensors to hydrogen has been widely investigated. However the influence of MOF modified film thickness on the selectivity of hydrogen sensors is seldom studied. Moreover the mechanism of the selectivity improvement of the sensors with MOF modified film is still unclear. In this paper we prepared nano-sized ZnO particles by a homogeneous precipitation method. ZnO nanoparticle (NP) gas sensors were prepared by screen printing technology. Then a dense ZIF-8 film was grown on the surface of the gas sensor by hydrothermal synthesis. The morphology the composition of the elements and the characters of the product were analyzed by X-ray diffraction analysis (XRD) transmission electron microscope (TEM) scanning electron microscope (SEM) energy dispersive spectrometer (EDS) Brunauer-Emmett-Teller (BET) and differential scanning calorimetry (DSC). It is found that the ZIF-8 film grown for 4 h cannot form a dense core-shell structure. The thickness of ZIF-8 reaches 130 nm at 20 h. Through the detection and analysis of hydrogen (1000 ppm) ethanol (100 ppm) and acetone (50 ppm) from 150 °C to 290 °C it is found that the response of the ZnO@ZIF-8 sensors to hydrogen has been significantly improved while the response to ethanol and acetone was decreased. By comparing the change of the response coefficient when the thickness of ZIF-8 is 130 nm the gas sensor has a significantly improved selectivity to hydrogen at 230 °C. The continuous increase of the thickness tends to inhibit selectivity. The mechanism of selectivity improvement of the sensors with different thickness of the ZIF-8 films is discussed.
Study of Activity and Super-Capacitance Exhibited by Bifunctional Raney 2.0 Catalyst for Alkaline Water-Splitting Electrolysis
Dec 2020
Publication
Low-cost high-performance coatings for hydrogen production via electrolytic water-splitting are of great importance for de-carbonising energy. In this study the Raney2.0 coating was analysed using various electrochemical techniques to assess its absolute performance and it was confirmed to have an extremely low overpotential for hydrogen evolution of just 28 mV at 10 mA/cm2. It was also confirmed to be an acceptable catalyst for oxygen evolution making it the highest performing simple bifunctional electrocatalyst known. The coating exhibits an extremely high capacitance of up to 1.7 F/cm2 as well as being able to store 0.61 J/cm2 in the form of temporary hydride deposits. A new technique is presented that performs a best-fit of a transient simulation of an equivalent circuit containing a constant phase element to cyclic voltammetry measurements. From this the roughness factor of the coating was calculated to be approximately 40000 which is the highest figure ever reported for this type of material. The coating is therefore an extremely useful improved bifunctional coating for the continued roll-out of alkaline electrolysis for large-scale renewable energy capture via hydrogen production.
Comparison of Hydrogen Powertrains with the Battery Powered Electric Vehicle and Investigation of Small-Scale Local Hydrogen Production Using Renewable Energy
Jan 2021
Publication
Climate change is one of the major problems that people face in this century with fossil fuel combustion engines being huge contributors. Currently the battery powered electric vehicle is considered the predecessor while hydrogen vehicles only have an insignificant market share. To evaluate if this is justified different hydrogen power train technologies are analyzed and compared to the battery powered electric vehicle. Even though most research focuses on the hydrogen fuel cells it is shown that despite the lower efficiency the often-neglected hydrogen combustion engine could be the right solution for transitioning away from fossil fuels. This is mainly due to the lower costs and possibility of the use of existing manufacturing infrastructure. To achieve a similar level of refueling comfort as with the battery powered electric vehicle the economic and technological aspects of the local small-scale hydrogen production are being investigated. Due to the low efficiency and high prices for the required components this domestically produced hydrogen cannot compete with hydrogen produced from fossil fuels on a larger scale
Internal Film Cooling with Discrete-Slot Injection Orifices in Hydrogen/Oxygen Engine Thrust Chambers
May 2022
Publication
In the present study a hydrogen and oxygen heat-sink engine thrust chamber and the corresponding injection faceplate with discrete slot orifices are devised to study the cooling performance near the faceplate region. Moreover a set of experiments and numerical simulations are conducted to evaluate the effects of various factors on combustion performance and film cooling efficiency. According to the obtained result the circumferential cooling efficiency has an M-shaped distribution in the near-injector region. Furthermore it has been discovered that when the film flow ratio increases so does the cooling efficiency. This is especially more pronounced in the range of 30–80 mm from the faceplate. The cooling efficiency is found to be proportional to the film flow rate ratio’s 0.4 power. Compared with the slot thickness the reduction in the slot width is more beneficial in improving the cooling efficiency and the advantage is more prominent for small film flow ratios. In addition when the amount of coolant is not enough the cooling effect of the discrete slot film orifice is better than that of the common cylindrical orifice. The present article demonstrates that setting the area ratio of the adjacent film orifices is an effective way to reduce the uneven circumferential distribution of the wall surface temperature.
Model of Local Hydrogen Permeability in Stainless Steel with Two Coexisting Structures
Apr 2021
Publication
The dynamics of hydrogen in metals with mixed grain structure is not well understood at a microscopic scale. One of the biggest issues facing the hydrogen economy is “hydrogen embrittlement” of metal induced by hydrogen entering and diffusing into the material. Hydrogen diffusion in metallic materials is difficult to grasp owing to the non-uniform compositions and structures of metal. Here a time-resolved “operando hydrogen microscope” was used to interpret local diffusion behaviour of hydrogen in the microstructure of a stainless steel with austenite and martensite structures. The martensite/austenite ratios differed in each local region of the sample. The path of hydrogen permeation was inferred from the time evolution of hydrogen permeation in several regions. We proposed a model of hydrogen diffusion in a dual-structure material and verified the validity of the model by simulations that took into account the transfer of hydrogen at the interfaces.
Direct Evidence for Solid-like Hydrogen in a Nanoporous Carbon Hydrogen Storage Material at Supercritical Temperatures
Jul 2015
Publication
Here we report direct physical evidence that confinement of molecular hydrogen (H2) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H2 at temperatures up to 67 K above the liquid vapor critical temperature of bulk H2. This extreme densification is attributed to confinement of H2 molecules in the optimally sized micropores and occurs at pressures as low as 0.02 MPa. The quantities of contained solid-like H2 increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorption isotherms. The demonstration of the existence of solid-like H2 challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H2 density. Thus this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.
Experimental Investigations Relevant for Hydrogen and Fission Product Issues Raised by the Fukushima Accident
Jan 2015
Publication
The accident at Japan's Fukushima Daiichi nuclear power plant in March 2011 caused by an earthquake and a subsequent tsunami resulted in a failure of the power systems that are needed to cool the reactors at the plant. The accident progression in the absence of heat removal systems caused Units 1-3 to undergo fuel melting. Containment pressurization and hydrogen explosions ultimately resulted in the escape of radioactivity from reactor containments into the atmosphere and ocean. Problems in containment venting operation leakage from primary containment boundary to the reactor building improper functioning of standby gas treatment system (SGTS) unmitigated hydrogen accumulation in the reactor building were identified as some of the reasons those added-up in the severity of the accident. The Fukushima accident not only initiated worldwide demand for installation of adequate control and mitigation measures to minimize the potential source term to the environment but also advocated assessment of the existing mitigation systems performance behavior under a wide range of postulated accident scenarios. The uncertainty in estimating the released fraction of the radionuclides due to the Fukushima accident also underlined the need for comprehensive understanding of fission product behavior as a function of the thermal hydraulic conditions and the type of gaseous aqueous and solid materials available for interaction e.g. gas components decontamination paint aerosols and water pools. In the light of the Fukushima accident additional experimental needs identified for hydrogen and fission product issues need to be investigated in an integrated and optimized way. Additionally as more and more passive safety systems such as passive autocatalytic recombiners and filtered containment venting systems are being retrofitted in current reactors and also planned for future reactors identified hydrogen and fission product issues will need to be coupled with the operation of passive safety systems in phenomena oriented and coupled effects experiments. In the present paper potential hydrogen and fission product issues raised by the Fukushima accident are discussed. The discussion focuses on hydrogen and fission product behavior inside nuclear power plant containments under severe accident conditions. The relevant experimental investigations conducted in the technical scale containment THAI (thermal hydraulics hydrogen aerosols and iodine) test facility (9.2 m high 3.2 m in diameter and 60 m3 volume) are discussed in the light of the Fukushima accident.
Electrification and Sustainable Fuels: Competing for Wind and Sun (complement to the Policy brief)
May 2021
Publication
This study seeks to answer a simple question: will we have enough renewable electricity to meet all of the EU's decarbonisation objectives and if not what should be the priorities and how to address the remaining needs for energy towards carbon neutrality? Indeed if not the policy push for green hydrogen would not be covered by enough green electricity to match the “energy efficiency and electrification first” approach outlined in the system integration communication and a prioritization of green electricity uses complemented by other solutions (import of green electricity or sustainable fuels CCS...) would be advisable [1]. On one hand we show that the principle “Energy efficiency and electrification first” results in an electricity demand which will be very difficult to satisfy domestically with renewable energy. On the other hand green hydrogen and other sustainable fuels will be needed for a carbon neutral industry for the replacement of the fuel for aviation and navigation and as strategic green energy reserves. The detailed modelling of these interactions is challenging given the large uncertainties on technology and infrastructure development. Therefore we offer a “15 minutes” decarbonization scenario based on general and transparent technical considerations and very straightforward “back-of-envelope” calculations. This working paper contains the calculations and assumptions in support of the accompanying policy brief with the same title which focuses instead on the main take-aways.
Estimation of Hydrogen Production using Wind Energy in Algeria
Aug 2015
Publication
In response to problems involved in the current crisis of petrol in Algeria with the decrease in the price of the oil barrel the rate of growth in domestic electricity demand and with an associated acceleration of global warming as a result of significantly increased greenhouse gas (GHG) emissions renewable energy seems today as a clean and strategic substitution for the next decades. However the greatest obstacles which face electric energy comes from renewable energy systems are often referred to the intermittency of these sources as well as storage and transport problems the need for their conversion into a versatile energy carrier in its use storable transportable and environmentally acceptable are required. Among all the candidates answering these criteria hydrogen presents the best answer. In the present work particular attention is paid to the production of hydrogen from wind energy. The new wind map of Algeria shows that the highest potential wind power was found in Adrar Hassi-R'Mel and Tindouf regions. The data obtained from these locations have been analyzed using Weibull probability distribution function. The wind energy produced in these locations is exploited for hydrogen production through water electrolysis. The objective of this paper is to realize a technological platform allowing the evaluation of emergent technologies of hydrogen production from wind energy using four wind energy conversion systems of 600 1250 1500 and 2000 kW rated capacity. The feasibility study shows that using wind energy in the selected sites is a promising solution. It is shown that the turbine " De Wind D7" is sufficient to supply the electricity and hydrogen with a least cost and a height capacity factor. The minimum cost of hydrogen production of 1.214 $/kgH2 is obtained in Adrar.
Hydrogen: Untapped Energy?
Jan 2012
Publication
Hydrogen has potential applications across our future energy systems due particularly to its relatively high energy weight ratio and because it is emission-free at the point of use. Hydrogen is also abundant and versatile in the sense that it could be produced from a variety of primary energy sources and chemical substances including water and used to deliver power in a variety of applications including fuel cell combined heat and power technologies. As a chemical feedstock hydrogen has been used for several decades and such expertise could be fed back into the relatively new areas of utilising hydrogen to meet growing energy demands.<br/>The UK interest in hydrogen is also growing with various industrial academic and governmental organisations investigating how hydrogen could be part of a diverse portfolio of options for a low carbon future. While hydrogen as an alternative fuel is yet to command mass-appeal in the UK energy market IGEM believes hydrogen is capable of allowing us to use the wide range of primary energy sources at our disposal in a much greener and sustainable way.<br/>IGEM also sees hydrogen playing a small but key role in the gas industry whereby excess renewable energy is used to generate hydrogen which is then injected into the gas grid for widespread distribution and consumption. Various studies suggest admixtures containing up to 10 – 50%v/v hydrogen could be safely administered into the existing natural gas infrastructure. However IGEM understands that this would currently not be permissible under the Gas Safety (Management) Regulations (GS(M)R) for gas conveyance here in the UK. Also proper assessments of the risks associated with adding hydrogen to natural gas streams will need to be performed so that such systems can be managed effectively.<br/>IGEM has also identified a need for standards that cover the safety requirements of hydrogen technologies particularly those pertaining to installations in commercial or domestic environments. IGEM also recommend that the technical measures used to determine separation distances for hydrogen installations particularly refuelling stations are re-assessed through a systematic identification and control of potential sources of ignition.<br/>Hydrogen has the potential to be a significant fuel of the future and part of a diverse portfolio of energy options capable of meeting growing energy needs. This report therefore seeks to demonstrate how hydrogen could be a potential option for energy storage and power generation in a diverse energy system. It also aims to inform the readers on the current state of hydrogen here in the UK and abroad. This report has been assembled for IGEM members interested bodies and the general public.
Water Removal from LOHC Systems
Oct 2020
Publication
Liquid organic hydrogen carriers (LOHC) store hydrogen by reversible hydrogenation of a carrier material. Water can enter the system via wet hydrogen coming from electrolysis as well as via moisture on the catalyst. Removing this water is important for reliable operation of the LOHC system. Different approaches for doing this have been evaluated on three stages of the process. Drying of the hydrogen before entering the LOHC system itself is preferable. A membrane drying process turns out to be the most efficient way. If the water content in the LOHC system is still so high that liquid–liquid demixing occurs it is crucial for water removal to enhance the slow settling. Introduction of an appropriate packing can help to separate the two phases as long as the volume flow is not too high. Further drying below the rather low solubility limit is challenging. Introduction of zeolites into the system is a possible option. Water adsorbs on the surface of the zeolite and moisture content is therefore decreased.
Hydrogen-based Systems for Integration of Renewable Energy in Power Systems: Achievements and Perspectives
Jul 2021
Publication
This paper is a critical review of selected real-world energy storage systems based on hydrogen ranging from lab-scale systems to full-scale systems in continuous operation. 15 projects are presented with a critical overview of their concept and performance. A review of research related to power electronics control systems and energy management strategies has been added to integrate the findings with outlooks usually described in separate literature. Results show that while hydrogen energy storage systems are technically feasible they still require large cost reductions to become commercially attractive. A challenge that affects the cost per unit of energy is the low energy efficiency of some of the system components in real-world operating conditions. Due to losses in the conversion and storage processes hydrogen energy storage systems lose anywhere between 60 and 85% of the incoming electricity with current technology. However there are currently very few alternatives for long-term storage of electricity in power systems so the interest in hydrogen for this application remains high from both industry and academia. Additionally it is expected that the share of intermittent renewable energy in power systems will increase in the coming decades. This could lead to technology development and cost reductions within hydrogen technology if this technology is needed to store excess renewable energy. Results from the reviewed projects indicate that the best solution from a technical viewpoint consists in hybrid systems where hydrogen is combined with short-term energy storage technologies like batteries and supercapacitors. In these hybrid systems the advantages with each storage technology can be fully exploited to maximize efficiency if the system is specifically tailored to the given situation. The disadvantage is that this will obviously increase the complexity and total cost of the energy system.<br/>Therefore control systems and energy management strategies are important factors to achieve optimal results both in terms of efficiency and cost. By considering the reviewed projects and evaluating operation modes and control systems new hybrid energy systems could be tailored to fit each situation and to reduce energy losses.
An Investigation of a (Vinylbenzyl) Trimethylammonium and N-Vinylimidazole-Substituted Poly (Vinylidene Fluoride-Co-Hexafluoropropylene) Copolymer as an Anion-Exchange Membrane in a Lignin-Oxidising Electrolyser
Jun 2021
Publication
Electrolysis is seen as a promising route for the production of hydrogen from water as part of a move to a wider “hydrogen economy”. The electro-oxidation of renewable feedstocks offers an alternative anode couple to the (high-overpotential) electrochemical oxygen evolution reaction for developing low-voltage electrolysers. Meanwhile the exploration of new membrane materials is also important in order to try and reduce the capital costs of electrolysers. In this work we synthesise and characterise a previously unreported anion-exchange membrane consisting of a fluorinated polymer backbone grafted with imidazole and trimethylammonium units as the ion-conducting moieties. We then investigate the use of this membrane in a lignin-oxidising electrolyser. The new membrane performs comparably to a commercially-available anion-exchange membrane (Fumapem) for this purpose over short timescales (delivering current densities of 4.4 mA cm−2 for lignin oxidation at a cell potential of 1.2 V at 70 °C during linear sweep voltammetry) but membrane durability was found to be a significant issue over extended testing durations. This work therefore suggests that membranes of the sort described herein might be usefully employed for lignin electrolysis applications if their robustness can be improved.
Acoustic and Psychoacoustic Levels from an Internal Combustion Engine Fueled by Hydrogen vs. Gasoline
Feb 2022
Publication
Whereas noise generated by road traffic is an important factor in urban pollution little attention has been paid to this issue in the field of hydrogen-fueled vehicles. The objective of this study is to analyze the influence of the type of fuel (gasoline or hydrogen) on the sound levels produced by a vehicle with an internal combustion engine. A Volkswagen Polo 1.4 vehicle adapted for its bi-fuel hydrogen-gasoline operation has been used. Tests were carried out with the vehicle when stationary to eliminate rolling and aerodynamic noise. Acoustics and psychoacoustics levels were measured both inside and outside the vehicle. A slight increase in the noise level has only been found outside when using hydrogen as fuel compared to gasoline. The increase is statistically significant can be quantified between 1.1 and 1.7 dBA and is mainly due to an intensification of the 500 Hz band. Loudness is also higher outside the vehicle (between 2 and 4 sones) when the fuel is hydrogen. Differences in sharpness and roughness values are lower than the just-noticeable difference (JND) values of the parameters. Higher noise levels produced by hydrogen can be attributed to its higher reactivity compared to gasoline.
A Review on the Properties of Iron Aluminide Intermetallics
Jan 2016
Publication
Iron aluminides have been among the most studied intermetallics since the 1930s when their excellent oxidation resistance was first noticed. Their low cost of production low density high strength-to-weight ratios good wear resistance ease of fabrication and resistance to high temperature oxidation and sulfurization make them very attractive as a substitute for routine stainless steel in industrial applications. Furthermore iron aluminides allow for the conservation of less accessible and expensive elements such as nickel and molybdenum. These advantages have led to the consideration of many applications such as brake disks for windmills and trucks filtration systems in refineries and fossil power plants transfer rolls for hot-rolled steel strips and ethylene crackers and air deflectors for burning high-sulfur coal. A wide application for iron aluminides in industry strictly depends on the fundamental understanding of the influence of (i) alloy composition; (ii) microstructure; and (iii) number (type) of defects on the thermo-mechanical properties. Additionally environmental degradation of the alloys consisting of hydrogen embrittlement anodic or cathodic dissolution localized corrosion and oxidation resistance in different environments should be well known. Recently some progress in the development of new micro- and nano-mechanical testing methods in addition to the fabrication techniques of micro- and nano-scaled samples has enabled scientists to resolve more clearly the effects of alloying elements environmental items and crystal structure on the deformation behavior of alloys. In this paper we will review the extensive work which has been done during the last decades to address each of the points mentioned above.
Low-Cost and Durable Bipolar Plates for Proton Exchange Membrane Electrolyzers
Mar 2017
Publication
Cost reduction and high efficiency are the mayor challenges for sustainable H2 production via proton exchange membrane (PEM) electrolysis. Titanium-based components such as bipolar plates (BPP) have the largest contribution to the capital cost. This work proposes the use of stainless steel BPPs coated with Nb and Ti by magnetron sputtering physical vapor deposition (PVD) and vacuum plasma spraying (VPS) respectively. The physical properties of the coatings are thoroughly characterized by scanning electron atomic force microscopies (SEM AFM); and X-ray diffraction photoelectron spectroscopies (XRD XPS). The Ti coating (50μm) protects the stainless steel substrate against corrosion while a 50- fold thinner layer of Nb decreases the contact resistance by almost one order of magnitude. The Nb/ Ti-coated stainless steel bipolar BPPs endure the harsh environment of the anode for more than 1000h of operation under nominal conditions showing a potential use in PEM electrolyzers for large-scale H2 production from renewables.
A Quantitative Assessment of the Hydrogen Storage Capacity of the UK Continental Shelf
Nov 2020
Publication
Increased penetration of renewable energy sources and decarbonisation of the UK's gas supply will require large-scale energy storage. Using hydrogen as an energy storage vector we estimate that 150 TWh of seasonal storage is required to replace seasonal variations in natural gas production. Large-scale storage is best suited to porous rock reservoirs. We present a method to quantify the hydrogen storage capacity of gas fields and saline aquifers using data previously used to assess CO2 storage potential. We calculate a P50 value of 6900 TWh of working gas capacity in gas fields and 2200 TWh in saline aquifers on the UK continental shelf assuming a cushion gas requirement of 50%. Sensitivity analysis reveals low temperature storage sites with sealing rocks that can withstand high pressures are ideal sites. Gas fields in the Southern North Sea could utilise existing infrastructure and large offshore wind developments to develop large-scale offshore hydrogen production.
Electrocatalytic Properties for the Hydrogen Evolution of the Electrodeposited Ni–Mo/WC Composites
May 2021
Publication
The catalytical activity for the hydrogen evolution reaction (HER) of the electrodeposited Ni–Mo/WC composites is examined in 1 M KOH solution. The structure surface morphology and surface composition is investigated using the scanning electron microscopy X-ray diffraction and X-ray photoelectron spectroscopy. The electrocatalytic properties for the HER is evaluated based on the cathodic polarization electrochemical impedance cyclic voltammetry and chronopotentiometry methods. The obtained results prove the superior catalytic activity for the HER of Ni–Mo/WC composites to Ni–Mo alloy. The catalytic activity of Ni–Mo/WC electrodes is determined by the presence of WC nanoparticles and Mo content in the metallic matrix. The best electrocatalytic properties are identified for Ni–Mo/WC composite with the highest Mo content and the most oxidized surface among the studied coatings. The impedance results reveal that the observed improvement in the catalytic activity is the consequence of high real surface area and high intrinsic catalytic activity of the composite.
Hydrogen for Australia’s Future
Aug 2018
Publication
The Hydrogen Strategy Group chaired by Australia’s Chief Scientist Dr Alan Finkel has today released a briefing paper on the potential domestic and export opportunities of a hydrogen industry in Australia.
Like natural gas hydrogen can be used to heat buildings and power vehicles. Unlike natural gas or petrol when hydrogen is burned there are no CO2 emissions. The only by-products are water vapour and heat.
Hydrogen is the most abundant element in the universe not freely available as a gas on Earth but bound into many common substances including water and fossil fuels.
Hydrogen was first formally presented as a credible alternative energy source in the early 1970s but never proved competitive at scale as an energy source – until now. We find that the worldwide demand for hydrogen is set to increase substantially over coming decades driven by Japan’s decision to put imported hydrogen at the heart of its economy. Production costs are falling technologies are progressing and the push for non-nuclear low-emissions fuels is building momentum. We conclude that Australia is remarkably well-positioned to benefit from the growth of hydrogen industries and markets.
Like natural gas hydrogen can be used to heat buildings and power vehicles. Unlike natural gas or petrol when hydrogen is burned there are no CO2 emissions. The only by-products are water vapour and heat.
Hydrogen is the most abundant element in the universe not freely available as a gas on Earth but bound into many common substances including water and fossil fuels.
Hydrogen was first formally presented as a credible alternative energy source in the early 1970s but never proved competitive at scale as an energy source – until now. We find that the worldwide demand for hydrogen is set to increase substantially over coming decades driven by Japan’s decision to put imported hydrogen at the heart of its economy. Production costs are falling technologies are progressing and the push for non-nuclear low-emissions fuels is building momentum. We conclude that Australia is remarkably well-positioned to benefit from the growth of hydrogen industries and markets.
Instantaneous Hydrogen Production from Ammonia by Non-thermal Arc Plasma Combining with Catalyst
Jul 2021
Publication
Owing to the storage and transportation problems of hydrogen fuel exploring new methods of the realtime hydrogen production from ammonia becomes attractive. In this paper non-thermal arc plasma (NTAP) combining with NiO/Al2O3 catalyst is developed to produce hydrogen from ammonia with high efficiency and large scale. The effects of ammonia gas flow rate and discharge power on the gas temperature electron density the hydrogen production rate and energy efficiency were investigated. Experimental results show that the optical emission spectrum of NTAP working with pure ammonia medium was dominated by the atom spectrum of Hα Hβ and molecular spectrum of NH component. Under the optimum experimental condition of plasma discharge the highest energy efficiency of hydrogen production reached 783.4 L/kW·h at NH3 gas flow rate of 30 SLM. When the catalyst was added and heated by the NTAP simultaneously the energy efficiency further increased to 1080.0 L/kW·h.
Hydrothermal Synthesis of Iridium-Substituted NaTaO3 Perovskites
Jun 2021
Publication
Iridium-containing NaTaO3 is produced using a one-step hydrothermal crystallisation from Ta2O5 and IrCl3 in an aqueous solution of 10 M NaOH in 40 vol% H2O2 heated at 240 °C. Although a nominal replacement of 50% of Ta by Ir was attempted the amount of Ir included in the perovskite oxide was only up to 15 mol%. The materials are formed as crystalline powders comprising cube-shaped crystallites around 100 nm in edge length as seen by scanning transmission electron microscopy. Energy dispersive X-ray mapping shows an even dispersion of Ir through the crystallites. Profile fitting of powder X-ray diffraction (XRD) shows expanded unit cell volumes (orthorhombic space group Pbnm) compared to the parent NaTaO3 while XANES spectroscopy at the Ir LIII-edge reveals that the highest Ir-content materials contain Ir4+. The inclusion of Ir4+ into the perovskite by replacement of Ta5+ implies the presence of charge-balancing defects and upon heat treatment the iridium is extruded from the perovskite at around 600 °C in air with the presence of metallic iridium seen by in situ powder XRD. The highest Ir-content material was loaded with Pt and examined for photocatalytic evolution of H2 from aqueous methanol. Compared to the parent NaTaO3 the Ir-substituted material shows a more than ten-fold enhancement of hydrogen yield with a significant proportion ascribed to visible light absorption.
Towards Ecological Alternatives in Bearing Lubrication
Jun 2021
Publication
Hydrogen is the cleanest fuel available because its combustion product is water. The internal combustion engine can in principle and without significant modifications run on hydrogen to produce mechanical energy. Regarding the technological solution leading to compact engines a question to ask is the following: Can combustion engine systems be lubricated with hydrogen? In general since many applications such as in turbomachines is it possible to use the surrounding gas as a lubricant? In this paper journal bearings global parameters are calculated and compared for steady state and dynamic conditions for different gas constituents such as air pentafluoropropane helium and hydrogen. Such a bearing may be promising as an ecological alternative to liquid lubrication.
Fuel Cells and Hydrogen Observatory 2019 EU and National Policies Report
Sep 2021
Publication
The policy module of the FCHO presents an overview of EU and national policies across various hydrogen and fuel cell related sectors. It provides a snapshot of the current state of hydrogen legislation and policy. Scope: While FCHO covers 38 entities around the world due to the completeness of the data at the moment of writing this report covers 29 entities. The report reflects data collected January 2019 – December 2019. Key Findings: Hydrogen policies are relatively commonplace among European countries but with large differences between member states. EU hydrogen leaders do not lag behind global outliers such as South Korea or Japan.
Aging Effects on Modelling and Operation of a Photovoltaic System with Hydrogen Storage
Jun 2021
Publication
In this work the aging effects on modelling and operation of a photovoltaic system with hydrogen storage in terms of energy production decrease and demand for additional hydrogen during 10 years of the system operation was analysed for the entire energy system for the first time. The analyses were performed with the support of experimental data for the renewable energy system composed of photovoltaic modules fuel cell electrolysers hydrogen storage and hydrogen backup.<br/>It has been found that the total degradation of the analysed system can be described by the proposed parameter – unit additional hydrogen consumption ratio. The results reveal a 33.2–36.2% increase of the unit fuel requirement from an external source after 10 years in reference to the initial condition. Degradation of the components can on the other hand be well described with the unit hydrogen consumption ratio by fuel cell for electricity or the unit electricity consumption ratio by electrolyser for hydrogen production which has been found to vary for the electrolyser in the range of 4.6–4.9% and for the fuel cell stack in the range of 13.4–15.1% during the 10 years of the system operation. The analyses indicate that this value depends on the load profile and PV module types and the system performance decline is non-linear."
2020 It's Time To Get Real
Mar 2020
Publication
Gi Editor Sharon Baker-Hallam sits down with Chris Stark CEO of the Committee on Climate Change to talk about this year’s Sir Denis Rooke Memorial Lecture the economic opportunities to be found in going green and why 2020 is a critical year in the ongoing battle against rising global temperatures
Hydrogen Tank Rupture in Fire in the Open Atmosphere: Hazard Distance Defined by Fireball
Feb 2021
Publication
The engineering correlations for assessment of hazard distance defined by a size of fireball after either liquid hydrogen spill combustion or high-pressure hydrogen tank rupture in a fire in the open atmosphere (both for stand-alone and under-vehicle tanks) are presented. The term “fireball size” is used for the maximum horizontal size of a fireball that is different from the term “fireball diameter” applied to spherical or semi-spherical shape fireballs. There are different reasons for a fireball to deviate from a spherical shape e.g. in case of tank rupture under a vehicle the non-instantaneous opening of tank walls etc. Two conservative correlations are built using theoretical analysis numerical simulations and experimental data available in the literature. The theoretical model for hydrogen fireball size assumes complete isobaric combustion of hydrogen in air and presumes its hemispherical shape as observed in the experiments and the simulations for tank rupturing at the ground level. The dependence of the fireball size on hydrogen mass and fireball’s diameter-to-height ratio is discussed. The correlation for liquid hydrogen release fireball is based on the experiments by Zabetakis (1964). The correlations can be applied as engineering tools to access hazard distances for scenarios of liquid or gaseous hydrogen storage tank rupture in a fire in the open atmosphere
HyDeploy Report: Summary of Gas Appliance and Installation Testing
Jun 2018
Publication
The HyDeploy project has undertaken a programme of work to assess the effect of hydrogen addition on the safety and performance of gas appliances and installations. A representative set of eight appliances have been assessed in laboratory experiments with a range of test gases that explored high and low Wobbe Index and hydrogen concentrations up to 28.4 % mol/mol. These tests have demonstrated that the addition of hydrogen does not affect the key hazard areas of CO production light back flame out or the operation of flame failure devices. It was identified that for some designs of gas fire appliances the operation of the oxygen depletion sensors may be affected by the addition of hydrogen. Testing of the gas fires that are present at Keele University that use oxygen depletion sensors have been shown to operate satisfactorily.<br/>A comprehensive onsite survey programme at Keele University has assessed 95% of the installations (126 of 133) that will receive the hydrogen blended gas during the HyDeploy trial. Where access to properties was not possible then the information obtained revealed that the appliances were annually checked either through British Gas service contracts or as a result of being rental properties. The onsite testing programme assessed installations for gas tightness and appliance combustion safety and operation with normal line gas G20 reference gas and two hydrogen blended gases. The checks identified a small number instances were remedial work was required to correct poor condition or operation. Only one case was found to be immediately dangerous which was capped off until repair work was undertaken. CO and smoke alarms were fitted in approximately half of properties and alarms were provided as required to the occupants. Gas tightness tests identified leaks in three installations. Where installations are gas tight then analysis has shown that no additional leaks would occur with hydrogen blended gas. There were no issues identified with the combustion performance of those appliances that were operating correctly and results were in line with those obtained in the laboratory testing programme.<br/>The findings of the Appliance and Installation testing program have been used to define the input values into the HyDeploy quantified risk assessment (QRA) where Keele University specific operation is different to GB as a whole or where the findings show the addition of hydrogen will change the risk profile.<br/>Click on supplements to see the other documents from this report
A Comprehensive Review of Microbial Electrolysis Cells (MEC) Reactor Designs and Configurations for Sustainable Hydrogen Gas Production
Nov 2015
Publication
Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to upscaling. Traditional MEC designs incorporated membranes but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.
On Capital Utilization in the Hydrogen Economy: The Quest to Minimize Idle Capacity in Renewables-rich Energy Systems
Oct 2020
Publication
The hydrogen economy is currently experiencing a surge in attention partly due to the possibility of absorbing variable renewable energy (VRE) production peaks through electrolysis. A fundamental challenge with this approach is low utilization rates of various parts of the integrated electricity-hydrogen system. To assess the importance of capacity utilization this paper introduces a novel stylized numerical energy system model incorporating the major elements of electricity and hydrogen generation transmission and storage including both “green” hydrogen from electrolysis and “blue” hydrogen from natural gas reforming with CO2 capture and storage (CCS). Concurrent optimization of all major system elements revealed that balancing VRE with electrolysis involves substantial additional costs beyond reduced electrolyzer capacity factors. Depending on the location of electrolyzers greater capital expenditures are also required for hydrogen pipelines and storage infrastructure (to handle intermittent hydrogen production) or electricity transmission networks (to transmit VRE peaks to electrolyzers). Blue hydrogen scenarios face similar constraints. High VRE shares impose low utilization rates of CO2 capture transport and storage infrastructure for conventional CCS and of hydrogen transmission and storage infrastructure for a novel process (gas switching reforming) that enables flexible power and hydrogen production. In conclusion all major system elements must be considered to accurately reflect the costs of using hydrogen to integrate higher VRE shares.
Emerging, Hydrogen-driven Electrochemical Water Purification
Jan 2022
Publication
Energy-efficient technologies for the remediation of water and generation of drinking water is a key towards sustainable technologies. Electrochemical desalination technologies are promising alternatives towards established methods such as reverse osmosis or ultrafiltration. In the last few years hydrogen-driven electrochemical water purification has emerged. This review article explores the concept of desalination fuel cells and capacitive-Faradaic fuel cells for ion separation.
Risk Assessment of the Large-Scale Hydrogen Storage in Salt Caverns
May 2021
Publication
Salt caverns are accepted as an ideal solution for high-pressure hydrogen storage. As well as considering the numerous benefits of the realization of underground hydrogen storage (UHS) such as high energy densities low leakage rates and big storage volumes risk analysis of UHS is a required step for assessing the suitability of this technology. In this work a preliminary quantitative risk assessment (QRA) was performed by starting from the worst-case scenario: rupture at the ground of the riser pipe from the salt cavern to the ground. The influence of hydrogen contamination by bacterial metabolism was studied considering the composition of the gas contained in the salt caverns as time variable. A bow-tie analysis was used to highlight all the possible causes (basic events) as well as the outcomes (jet fire unconfined vapor cloud explosion (UVCE) toxic chemical release) and then consequence and risk analyses were performed. The results showed that a UVCE is the most frequent outcome but its effect zone decreases with time due to the hydrogen contamination and the higher contents of methane and hydrogen sulfide.
Mobility from Renewable Electricity: Infrastructure Comparison for Battery and Hydrogen Fuel Cell Vehicles
May 2018
Publication
This work presents a detailed breakdown of the energy conversion chains from intermittent electricity to a vehicle considering battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs). The traditional well-to-wheel analysis is adapted to a grid to mobility approach by introducing the intermediate steps of useful electricity energy carrier and on-board storage. Specific attention is given to an effective coupling with renewable electricity sources and associated storage needs. Actual market data show that compared to FCEVs BEVs and their infrastructure are twice as efficient in the conversion of renewable electricity to a mobility service. A much larger difference between BEVs and FCEVs is usually reported in the literature. Focusing on recharging events this work additionally shows that the infrastructure efficiencies of both electric vehicle (EV) types are very close with 57% from grid to on-board storage for hydrogen refilling stations and 66% for fast chargers coupled with battery storage. The transfer from the energy carrier at the station to on-board storage in the vehicle accounts for 9% and 12% of the total energy losses of these two modes respectively. Slow charging modes can achieve a charging infrastructure efficiency of 78% with residential energy storage systems coupled with AC chargers.
Large-scale Stationary Hydrogen Storage via Liquid Organic Hydrogen Carriers
Aug 2021
Publication
Large-scale stationary hydrogen storage is critical if hydrogen is to fulfill its promise as a global energy carrier. While densified storage via compressed gas and liquid hydrogen is currently the dominant approach liquid organic molecules have emerged as a favorable storage medium because of their desirable properties such as low cost and compatibility with existing fuel transport infrastructure. This perspective article analytically investigates hydrogenation systems' technical and economic prospects using liquid organic hydrogen carriers (LOHCs) to store hydrogen at a large scale compared to densified storage technologies and circular hydrogen carriers (mainly ammonia and methanol). Our analysis of major system components indicates that the capital cost for liquid hydrogen storage is more than two times that for the gaseous approach and four times that for the LOHC approach. Ammonia and methanol could be attractive options as hydrogen carriers at a large scale because of their compatibility with existing liquid fuel infrastructure. However their synthesis and decomposition are energy and capital intensive compared to LOHCs. Together with other properties such as safety these factors make LOHCs a possible option for large-scale stationary hydrogen storage. In addition hydrogen transportation via various approaches is briefly discussed. We end our discussions by identifying important directions for future research on LOHCs.
Techno-economic Assessment of Hydrogen Production from Seawater
Nov 2022
Publication
Population growth and the expansion of industries have increased energy demand and the use of fossil fuels as an energy source resulting in release of greenhouse gases (GHG) and increased air pollution. Countries are therefore looking for alternatives to fossil fuels for energy generation. Using hydrogen as an energy carrier is one of the most promising alternatives to replace fossil fuels in electricity generation. It is therefore essential to know how hydrogen is produced. Hydrogen can be produced by splitting the water molecules in an electrolyser using the abondand water resources which are covering around ⅔ of the Earth's surface. Electrolysers however require high-quality water with conductivity in the range of 0.1–1 μS/cm. In January 2018 there were 184 offshore oil and gas rigs in the North Sea which may be excellent sites for hydrogen production from seawater. The hydrogen production process reported in this paper is based on a proton exchange membrane (PEM) electrolyser with an input flow rate of 300 L/h. A financially optimal system for producing demineralized water from seawater with conductivity in the range of 0.1–1 μS/cm as the input for electrolyser by WAVE (Water Application Value Engine) design software was studied. The costs of producing hydrogen using the optimised system was calculated to be US$3.51/kg H2. The best option for low-cost power generation using renewable resources such as photovoltaic (PV) devices wind turbines as well as electricity from the grid was assessed considering the location of the case considered. All calculations were based on assumption of existing cable from the grid to the offshore meaning that the cost of cables and distribution infrastructure were not considered. Models were created using HOMER Pro (Hybrid Optimisation of Multiple Energy Resources) software to optimise the microgrids and the distributed energy resources under the assumption of a nominal discount rate inflation rate project lifetime and CO2 tax in Norway. Eight different scenarios were examined using HOMER Pro and the main findings being as follows:<br/>The cost of producing water with quality required by the electrolyser is low compared with the cost of electricity for operation of the electrolyser and therefore has little effect on the total cost of hydrogen production (less than 1%).<br/>The optimal solution was shown to be electricity from the grid which has the lowest levelised cost of energy (LCOE) of the options considered. The hydrogen production cost using electricity from the grid was about US$ 5/kg H2.<br/>Grid based electricity resulted in the lowest hydrogen production cost even when costs for CO2 emissions in Norway that will start to apply in 2025 was considered being approximately US$7.7/kg H2.<br/>From economical point of view wind energy was found to be a more economical than solar.
Public Acceptance for the Implementation of Hydrogen Self-refueling Stations
Sep 2021
Publication
The utilization of hydrogen energy is important for achieving a low-carbon society. Japan has set ambitious goals for hydrogen stations and fuel cell vehicles focusing on the introduction and dissemination of self-refuelling systems. This paper evaluates public trust in the fuel equipment and self-handling technology related to self-refuelling hydrogen stations and compares it with that for widespread gasoline stations. To this end the results of an online survey of 300 people with Japanese driver licenses are reported and analyzed. The results show that trust in the equipment and self-handling is more important for the user than trust in the fuel. In addition to introduce and disseminate new technology such as hydrogen stations users must be made aware of the risk of using the technology until it becomes as familiar as existing gasoline station technology.
Economic Analysis of a High-pressure Urban Pipeline Concept (HyLine) for Delivering Hydrogen to Retail Fueling Stations
Nov 2019
Publication
Reducing the cost of delivering hydrogen to fuelling stations and dispensing it into fuel cell electric vehicles (FCEVs) is one critical element of efforts to increase the cost-competitiveness of FCEVs. Today hydrogen is primarily delivered to stations by trucks. Pipeline delivery is much rarer: one urban U.S. station has been supplied with 800-psi hydrogen from an industrial hydrogen pipeline since 2011 and a German station on the edge of an industrial park has been supplied with 13000-psi hydrogen from a pipeline since 2006. This article compares the economics of existing U.S. hydrogen delivery methods with the economics of a high-pressure scalable intra-city pipeline system referred to here as the “HyLine” system. In the HyLine system hydrogen would be produced at urban industrial or commercial sites compressed to 15000 psi stored at centralized facilities delivered via high-pressure pipeline to retail stations and dispensed directly into FCEVs. Our analysis of retail fuelling station economics in Los Angeles suggests that as FCEV demand for hydrogen in an area becomes sufficiently dense pipeline hydrogen delivery gains an economic advantage over truck delivery. The HyLine approach would also enable cheaper dispensed hydrogen compared with lower-pressure pipeline delivery owing to economies of scale associated with integrated compression and storage. In the largest-scale fuelling scenario analyzed (a network of 24 stations with capacities of 1500 kg/d each and hydrogen produced via steam methane reforming) HyLine could potentially achieve a profited hydrogen cost of $5.3/kg which is approximately equivalent to a gasoline cost of $2.7/gal (assuming FCEVs offer twice the fuel economy of internal combustion engine vehicles and vehicle cost is competitive). It is important to note that significant effort would be required to develop technical knowledge codes and standards that would enable a HyLine system to be viable. However our preliminary analysis suggests that the HyLine approach merits further consideration based on its potential economic advantages. These advantages could also include the value of minimizing retail space used by hydrogen compression and storage sited at fuelling stations which is not reflected in our analysis.
A Novel Integration of a Green Power-to-ammonia to Power System: Reversible Solid Oxide Fuel Cell for Hydrogen and Power Production Coupled with an Ammonia Synthesis Unit
Mar 2021
Publication
Renewable energy is a key solution in maintaining global warming below 2 °C. However its intermittency necessitates the need for energy conversion technologies to meet demand when there are insufficient renewable energy resources. This study aims to tackle these challenges by thermo-electrochemical modelling and simulation of a reversible solid oxide fuel cell (RSOFC) and integration with the Haber Bosch process. The novelty of the proposed system is usage of nitrogen-rich fuel electrode exhaust gas for ammonia synthesis during fuel cell mode which is usually combusted to prevent release of highly flammable hydrogen into the environment. RSOFC round-trip efficiencies of 41–53% have been attained when producing excess ammonia (144 kg NH3/hr) for the market and in-house consumption respectively. The designed system has the lowest reported ammonia electricity consumption of 6.4–8.21 kWh/kg NH3 power-to-hydrogen power-to-ammonia and power-generation efficiencies of 80% 55–71% and 64–66%.
Constrained Extended Kalman Filter Design and Application for On-line State Estimation of High-order Polymer Electrolyte Membrane Fuel Cell Systems
Jun 2021
Publication
In this paper an alternative approach to extended Kalman filtering (EKF) for polymer electrolyte membrane fuel cell (FC) systems is proposed. The goal is to obtain robust real-time capable state estimations of a high-order FC model for observer applications mixed with control or fault detection. The introduced formulation resolves dependencies on operating conditions by successive linearization and constraints allowing to run the nonlinear FC model at significantly lower sampling rates than with standard approaches. The proposed method provides state estimates for challenging operating conditions such as shut-down and start-up of the fuel cell for which the unconstrained EKF fails. A detailed comparison with the unscented Kalman filter shows that the proposed EKF reconstructs the outputs equally accurate but nine times faster. An application to measured data from an FC powered passenger car is presented yielding state estimates of a real FC system which are validated based on the applied model.
No more items...