Production & Supply Chain
Hydrogen Production from Methanol–Water Solution and Pure Water Electrolysis Using Nanocomposite Perfluorinated Sulfocationic Membranes Modified by Polyaniline
Oct 2022
Publication
In this work we report the preparation of Nafion membranes containing two different nanocomposite MF-4SC membranes modified with polyaniline (PANI) by the casting method through two different polyaniline infiltration procedures. These membranes were evaluated as a polymer electrolyte membrane for water electrolysis. Operating conditions were optimized in terms of current density stability and methanol concentration. A study was made on the effects on the cell performance of various parameters such as methanol concentration water and cell voltage. The energy required for pure water electrolysis was analyzed at different temperatures for the different membranes. Our experiments showed that PEM electrolyzers provide hydrogen production of 30 mL/min working at 160 mA/cm2 . Our composite PANI membranes showed an improved behavior over pristine perfluorinated sulfocationic membranes (around 20% reduction in specific energy). Methanol–water electrolysis required considerably less (around 65%) electrical power than water electrolysis. The results provided the main characteristics of aqueous methanol electrolysis in which the power consumption is 2.34 kW h/kg of hydrogen at current densities higher than 0.5 A/cm2 . This value is ~20-fold times lower than the electrical energy required to produce 1 kg of hydrogen by water electrolysis.
Photocatalytic Water Splitting: How Far Away Are We from Being Able to Industrially Produce Solar Hydrogen?
Oct 2022
Publication
Solar water splitting (SWS) has been researched for about five decades but despite successes there has not been a big breakthrough advancement. While the three fundamental steps light absorption charge carrier separation and diffusion and charge utilization at redox sites are given a great deal of attention either separately or simultaneously practical considerations that can help to increase efficiency are rarely discussed or put into practice. Nevertheless it is possible to increase the generation of solar hydrogen by making a few little but important adjustments. In this review we talk about various methods for photocatalytic water splitting that have been documented in the literature and importance of the thin film approach to move closer to the large-scale photocatalytic hydrogen production. For instance when comparing the film form of the identical catalyst to the particulate form it was found that the solar hydrogen production increased by up to two orders of magnitude. The major topic of this review with thin-film forms is discussion on several methods of increased hydrogen generation under direct solar and one-sun circumstances. The advantages and disadvantages of thin film and particle technologies are extensively discussed. In the current assessment potential approaches and scalable success factors are also covered. As demonstrated by a film-based approach the local charge utilization at a zero applied potential is an appealing characteristic for SWS. Furthermore we compare the PEC-WS and SWS for solar hydrogen generation and discuss how far we are from producing solar hydrogen on an industrial scale. We believe that the currently employed variety of attempts may be condensed to fewer strategies such as film-based evaluation which will create a path to address the SWS issue and achieve sustainable solar hydrogen generation.
Storage Batteries in Photovoltaic-electrochemical Device for Solar Hydrogen Production
Aug 2021
Publication
Hydrogen produced by water electrolysis and electrochemical batteries are widely considered as primary routes for the long- and short-term storage of photovoltaic (PV) energy. At the same time fast power ramps and idle periods in PV power generation may cause degradation of water splitting electrochemical (EC) cells. Implementation of batteries in PV-EC systems is a viable option for smoothening out intermittence of PV power. Notably the spreading of PV energy over the diurnal cycle reduces power of the EC cell and thus its overpotential loss. We study these potential advantages theoretically and experimentally for a simple parallel connected combination of PV EC and battery cells (PV-EC-B) operated without power management electronics. We show feasibility of the unaided operation of PV-EC-B device in a relevant duty cycle and explore how PV-EC-B system can operate at higher solar-to-hydrogen efficiency than the equivalent reference PV-EC system despite the losses caused by the battery.
Overview of the Hydrogen Production by Plasma-Driven Solution Electrolysis
Oct 2022
Publication
This paper reviews the progress in applying the plasma-driven solution electrolysis (PDSE) which is also referred to as the contact glow-discharge electrolysis (CGDE) or plasma electrolysis for hydrogen production. The physicochemical processes responsible for the formation of PDSE and effects occurring at the discharge electrode in the cathodic and anodic regimes of the PDSE operation are described. The influence of the PDSE process parameters especially the discharge polarity magnitude of the applied voltage type and concentration of the typical electrolytic solutions (K2CO3 Na2CO3 KOH NaOH H2SO4 ) presence of organic additives (CH3OH C2H5OH CH3COOH) temperature of the electrolytic solution the active length and immersion depth of the discharge electrode into the electrolytic solution on the energy efficiency (%) energy yield (g(H2 )/kWh) and hydrogen production rate (g(H2 )/h) is presented and discussed. This analysis showed that in the cathodic regime of PDSE the hydrogen production rate is 33.3 times higher than that in the anodic regime of PDSE whereas the Faradaic and energy efficiencies are 11 and 12.5 times greater respectively than that in the anodic one. It also revealed the energy yield of hydrogen production in the cathodic regime of PDSE in the methanol–water mixture as the electrolytic solution is 3.9 times greater compared to that of the alkaline electrolysis 4.1 times greater compared to the polymer electrolyte membrane electrolysis 2.8 times greater compared to the solid oxide electrolysis 1.75 times greater than that obtained in the microwave (2.45 GHz) plasma and 5.8% greater compared to natural gas steam reforming.
Polymer Electrolyte Membrane Electrolyzer and Fuel Cell System Characterization for Power System Frequency Control
Mar 2022
Publication
This work focuses on tests for control reserve of a novel Power-to-Gas-to-Power platform based on proton exchange membrane technologies and on pure oxygen instead of air in the re-electrification process. The technologies are intended as a further option to stabilize the power system therefore helping integrating renewable energy into the power system. The tests are based on the pre-qualification tests used by Swissgrid but are not identical in order to capture the maximum dynamics by the plants. The main characteristics identified are the ramping capabilities of ±8% per unit per second for the electrolyzer system and ±33% per unit per second for the fuel cell system. The ramping capabilities are mainly limited by the underlying processes of polymer electrolyte membrane technologies. Additionally the current and projected round-trip efficiencies for Power-to-Gas-to-Power of 39% in 2025 and 48% in 2040 are derived. Furthermore during the successful tests the usage of oxygen in the present Power-to-Gas and Gas-to-Power processes and its influence on the dynamics and the round-trip efficiency was assessed. In consequence fundamental data on the efficiency and the dynamics of the Power-to-Gas-to-Power technologies is presented. This data can serve as basis for prospective assessments on the suitability of the technologies investigated for frequency control in power systems.
Life Cycle Assessment and Economic Analysis of an Innovative Biogas Membrane Reformer for Hydrogen Production
Feb 2019
Publication
This work investigates the environmental and economic performances of a membrane reactor for hydrogen production from raw biogas. Potential benefits of the innovative technology are compared against reference hydrogen production processes based on steam (or autothermal) reforming water gas shift reactors and a pressure swing adsorption unit. Both biogas produced by landfill and anaerobic digestion are considered to evaluate the impact of biogas composition. Starting from the thermodynamic results the environmental analysis is carried out using environmental Life cycle assessment (LCA). Results show that the adoption of the membrane reactor increases the system efficiency by more than 20 percentage points with respect to the reference cases. LCA analysis shows that the innovative BIONICO system performs better than reference systems when biogas becomes a limiting factor for hydrogen production to satisfy market demand as a higher biogas conversion efficiency can potentially substitute more hydrogen produced by fossil fuels (natural gas). However when biogas is not a limiting factor for hydrogen production the innovative system can perform either similar or worse than reference systems as in this case impacts are largely dominated by grid electric energy demand and component use rather than conversion efficiency. Focusing on the economic results hydrogen production cost shows lower value with respect to the reference cases (4 €/kgH2 vs 4.2 €/kgH2) at the same hydrogen delivery pressure of 20 bar. Between landfill and anaerobic digestion cases the latter has the lower costs as a consequence of the higher methane content.
Development Concept of Integrated Energy Network and Hydrogen Energy Industry Based on Hydrogen Production Using Surplus Hydropower
Apr 2020
Publication
The development of hydropower industry is progressing rapidly in China and the installed capacity and power generation are increasing year by year. However due to factors such as transmission channels and power grid peaking capacity hydropower consumption in some areas is facing greater pressure. As an excellent medium for energy interconnection hydrogen energy can play an important role in promoting hydropower consumption. This paper introduces the current status and trends of hydrogen energy development in major developed countries and China and analyzes the current status of China’s hydropower abandoned water. Based on the production of hydrogen using surplus hydropower in the Dadu River Basin in Sichuan an integrated energy network research plan including hydropower electrolytic hydrogen production storage and transportation hydrogen refueling and hydrogen-powered vehicles is proposed. At the same time the development concept of hydrogen energy industry including hydrogen energy source economy hydrogen energy industry ecosphere and hydrogen energy sky road in western Sichuan is also proposed.
Hydrogenerally - Episode 6: Waste to Hydrogen
Nov 2022
Publication
In this sixth episode Steffan Eldred Hydrogen Innovation Network Knowledge Transfer Manager and Debra Jones Chemistry Knowledge Transfer Manager from Innovate UK KTN discuss why converting waste to hydrogen is so important and explore the hydrogen transition opportunities and challenges in this sector alongside their special guest Rob Dent Senior Research Engineer - Energy Linde and Application Sales Engineer at BOC UK & Ireland.
The podcast can be found on their website.
The podcast can be found on their website.
Hydrogen Production in the Light of Sustainability: A Comparative Study on the Hydrogen Production Technologies Using the Sustainability Index Assessment Method
Sep 2021
Publication
Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies fossil fuels have been used in hydrogen production but due to several limitations especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods water or biomass materials are used as the raw material for hydrogen production. In this article after a brief review of different hydrogen production methods concerning the required raw material these methods are examined and ranked from different aspects of economic social environmental and energy and exergy analysis sustainability. In the following the current position of hydrogen production is discussed. Finally according to the introduced methods their advantages and disadvantages solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.
Fuel Cells and Hydrogen Observatory Hydrogen Molecule Market Report
Sep 2021
Publication
The purpose of the hydrogen molecule market analysis is to track changes in the structure of hydrogen supply and demand in Europe. This report is mainly focused on presenting the current landscape - that will allow for future year-on-year comparisons in order to assess the progress Europe is making with regards to deployment of clean hydrogen production capacities as well as development of demand for clean hydrogen from emerging new hydrogen applications in the mobility sector or in industry. The following report summarizes the hydrogen molecule market landscape and contains data about hydrogen production and consumption in the EEA countries (EU countries together with Switzerland Norway Iceland and Liechtenstein). Hydrogen production capacity is presented by country and by technology whereas the hydrogen consumption data is presented by country and by end-use sector. The analysis undertaken for this report was completed using data available at the end of 2019. Hydrogen market (on both the demand and supply side) is dominated by ammonia and refining industries with three countries (DE NL PL) responsible for almost half hydrogen consumption. Today hydrogen is overwhelmingly produced by reforming of fossil fuels (mostly natural gas). Clean hydrogen production capacities are insignificant with blue hydrogen capacities at below 1% and green hydrogen production capacity below 0.1% of total.
Economic Analysis of P2G Green Hydrogen Generated by Existing Wind Turbines on Jeju Island
Dec 2022
Publication
Every wind turbine is subject to fluctuations in power generation depending on climatic conditions. When electricity supply exceeds demand wind turbines are forced to implement curtailment causing a reduction in generation efficiency and commercial loss to turbine owners. Since the frequency and amount of curtailment of wind turbines increases as the amount of renewable energy become higher on Jeju Island in South Korea Jeju is configuring a Power to Gas (P2G) water electrolysis system that will be connected to an existing wind farm to use the “wasted energy”. In this study economic analysis was performed by calculating the production cost of green hydrogen and sensitivity analysis evaluated the variance in hydrogen cost depending on several influential factors. Approaches to lower hydrogen costs are necessary for the following reasons. The operating company needs a periodical update of hydrogen sale prices by reflecting a change in the system margin price (SMP) with the highest sensitivity to hydrogen cost. Technical development to reduce hydrogen costs in order to reduce power consumption for producing hydrogen and a decrease in annual reduction rate for the efficiency of water electrolysis is recommended. Discussions and research regarding government policy can be followed to lower the hydrogen cost.
Everything About Hydrogen Podcast: Easter Eggs
Feb 2023
Publication
On today’s episode of Everything About Hydrogen we speak with Raffi Garabedian CEO and Co-Founder of Electric Hydrogen (EH2) a deep decarbonization company pioneering new technology for low cost high efficiency fossil free hydrogen systems. By using electrolyzers many times larger than the industry standard EH2 aims to help eliminate more than 30% of global GHG emissions from difficult to electrify sectors like steel ammonia and freight.
We are excited to learn more from Raffi about the EH2 technology lessons learned by scaling First Solar and what we might expect to see next.
The podcast can be found on their website.
We are excited to learn more from Raffi about the EH2 technology lessons learned by scaling First Solar and what we might expect to see next.
The podcast can be found on their website.
Water Electrolysis and Hydrogen in the European Union
Nov 2022
Publication
Renewable and low carbon hydrogen is both an energy carrier able to produce other fuels and downstream products such as the e-fuels or e-ammonia and a decarbonised gas produced through renewable electricity. It has the potential to decarbonise hard to abate sectors which are difficult to directly electrify and play a crucial role in achieving net zero emissions target in 2050. The European Commission has recently outlined the policy context and necessary actions for the development and deployment of renewable and low carbon hydrogen within the 2030 time horizon with the Hydrogen Strategy for a Climate Neutral Europe Communication (the Hydrogen Strategy). The REPowerEU Communication4 has further addressed the joint EU and Member State actions needed in the context of the crisis triggered by the invasion of Ukraine in February 2022 and the necessity to phase out dependence on Russian supplies. The EC has strengthened the policy narrative around hydrogen and increased objectives for a pan European framework accelerating and upscaling the production of RES and low-carbon hydrogen. The main objectives and actions of the REPowerEU Plan which build on the Hydrogen Strategy are the deployment of several tens of GW of electrolyser capacity and the production and imports of 10 Mt and 10 Mt respectively of renewable hydrogen by 2030. Currently the most mature and promising green hydrogen production technology is water electrolysis. The main technologies5 considered in this report are: Alkaline electrolysis Polymer Exchange Membrane (PEM) electrolysis Solid Oxide electrolysis and Anion Exchange Membrane electrolysers (AEM).
Technical Performance and Environmental Assessment of an Ionic Liquid-based CCS Process for Hydrogen Production
Apr 2023
Publication
Hydrogen (H2) production combined with carbon capture and storage (CCS) is anticipated to be an important technology contributing to reduce the carbon footprint of current fossil-based H2 production systems. This work addresses for the first time the techno-environmental assessment of a CCS process based on the ionic liquid [Bmim][Acetate] for H2 production by steam methane reforming (SMR) and the comparison to conventional amine-based systems. Two different SMR plants using MDEA or [Bmim][Acetate] for CO2 capture were rigorously modelled using Aspen Plus to compute material and energy needs and emissions. Literature and simulation results were then used to perform a life cycle impact assessment (LCIA) of these processes based on the ReCiPe model. Solvent synthesis CCS process and hydrogen production stages were considered for the cradle-to-gate analysis. Results showed that although [Bmim][Acetate] is a priori more harmful to the environment than amines (in a kg-to-kg comparison) LCIAs carried out for both CCS processes showed from 5 to 17 % lower environmental impacts values for all estimated categories when using [Bmim][Acetate] due to a 9.4 % more energy-efficient performance than MDEA which also reduced a 17.4 % the total utility cost. Indeed if a typical amine loss rate of 1.6 kg/tCO2 is assumed the values of the environmental impacts increase up to 14 % for the IL-based CCS plant but still maintaining its favorable results over MDEA. As consequence the SMR plant with the IL-based CCS system exhibited 3–20 % lower values for most of the studied impact categories. These results contribute to shed some light on evaluating the sustainability of ILs with respect to conventional solvents for CO2 capture and to guide the synthesis of new more sustainable ILs but also they would be used to compare the environmental burdens from the synthesis and process performance of other promising ILs for CO2 capture that are not environmentally assed yet.
Economic and Environmental Assessment of Hydrogen Production from Brazilian Energy Grid
Apr 2023
Publication
The Brazilian energy grid is considered as one of the cleanest in the world because it is composed of more than 80% of renewable energy sources. This work aimed to apply the levelized costs (LCOH) and environmental cost accounting techniques to demonstrate the feasibility of producing hydrogen (H2 ) by alkaline electrolysis powered by the Brazilian energy grid. A project of hydrogen production with a lifetime of 20 years had been evaluated by economical and sensitivity analysis. The production capacity (8.89 to 46.67 kg H2/h) production volume (25 to 100%) hydrogen sale price (1 to 5 USD/kg H2 ) and the MAR rate were varied. Results showed that at 2 USD/kg H2 all H2 production plant sizes are economically viable. On this condition a payback of fewer than 4 years an IRR greater than 31 a break-even point between 56 and 68% of the production volume and a ROI above 400% were found. The sensitivity analysis showed that the best economic condition was found at 35.56 kg H2/h of the plant size which generated a net present value of USD 10.4 million. The cost of hydrogen varied between 1.26 and 1.64 USD/kg and a LCOH of 37.76 to 48.71 USD/MWh. LCA analysis showed that the hydrogen production project mitigated from 26 to 131 thousand tons of CO2 under the conditions studied.
Prospects and Technical Challenges in Hydrogen Production through Dry Reforming of Methane
Mar 2022
Publication
Environmental issues related to greenhouse gases (GHG) emissions have pushed the development of new technologies that will allow the economic production of low-carbon energy vectors such as hydrogen (H2 ) methane (CH4 ) and liquid fuels. Dry reforming of methane (DRM) has gained increased attention since it uses CH4 and carbon dioxide (CO2 ) which are two main greenhouse gases (GHG) as feedstock for the production of syngas which is a mixture of H2 and carbon monoxide (CO) and can be used as a building block for the production of fuels. Since H2 has been identified as a key enabler of the energy transition a lot of studies have aimed to benefit from the environmental advantages of DRM and to use it as a pathway for a sustainable H2 production. However there are several challenges related to this process and to its use for H2 production such as catalyst deactivation and the low H2/CO ratio of the syngas produced which is usually below 1.0. This paper presents the recent advances in the catalyst development for H2 production via DRM the processes that could be combined with DRM to overcome these challenges and the current industrial processes using DRM. The objective is to assess in which conditions DRM could be used for H2 production and the gaps in literature data preventing better evaluation of the environmental and economic potential of this process.
Feasibility of Hydrogen Production from Steam Reforming of Biodiesel (FAME) Feedstock on Ni-supported Catalysts
Jan 2015
Publication
The catalytic steam reforming of biodiesel was examined over Ni-alumina and Ni–ceria–zirconia catalysts at atmospheric pressure. Effects of temperatures of biodiesel preheating/vaporising (190–365 ◦C) and reforming (600–800 ◦C) molar steam to carbon ratio (S/C = 2–3) and residence time in the reformer represented by the weight hourly space velocity ‘WHSV’ of around 3 were examined for 2 h. Ni supported on calcium aluminate and on ceria–zirconia supports achieved steady state hydrogen product stream within 90% of the equilibrium yields although 4% and 1% of the carbon feed had deposited on the catalysts respectively during the combined conditions of start-up and steady state. Addition of dopants to ceria–zirconia supported catalyst decreased the performance of the catalyst. Increase in S/C ratio had the expected positive effects of higher H2 yield and lower carbon deposition.
Hydrogen Production: State of Technology
May 2020
Publication
Presently hydrogen is for ~50% produced by steam reforming of natural gas – a process leading to significant emissions of greenhouse gas (GHG). About 30% is produced from oil/naphtha reforming and from refinery/chemical industry off-gases. The remaining capacity is covered for 18% from coal gasification 3.9% from water electrolysis and 0.1% from other sources. In the foreseen future hydrogen economy green hydrogen production methods will need to supply hydrogen to be used directly as fuel or to generate synthetic fuels to produce ammonia and other fertilizers (viz. urea) to upgrade heavy oils (like oil sands) and to produce other chemicals. There are several ways to produce H2 each with limitations and potential such as steam reforming electrolysis thermal and thermo-chemical water splitting dark and photonic fermentation; gasification and catalytic decomposition of methanol. The paper reviews the fundamentals and potential of these alternative process routes. Both thermo-chemical water splitting and fermentation are marked as having a long term but high "green" potential.
Baseload Electricity and Hydrogen Supply Based on Hybrid PV-wind Power Plants
Sep 2019
Publication
The reliable supplies of electricity and hydrogen required for 100% renewable energy systems have been found to be achievable by utilisation of a mix of different resources and storage technologies. In this paper more demanding parameter conditions than hitherto considered are used in measurement of the reliability of variable renewable energy resources. The defined conditions require that supply of baseload electricity (BLEL) and baseload hydrogen (BLH2) occurs solely using cost-optimised configurations of variable photovoltaic solar power onshore wind energy and balancing technologies. The global scenario modelling is based on hourly weather data in a 0.45° × 0.45° spatial resolution. Simulations are conducted for Onsite and Coastal Scenarios from 2020 to 2050 in 10-year time-steps. The results show that for 7% weighted average cost of capital Onsite BLEL can be generated at less than 119 54 41 and 33 €/MWhel in 2020 2030 2040 and 2050 respectively across the best sites with a maximum 20000 TWh annual cumulative generation potential. Up to 20000 TWhH2HHV Onsite BLH2 can be produced at less than 66 48 40 and 35 €/MWhH2HHV in 2020 2030 2040 and 2050 respectively. A partially flexible electricity demand at 8000 FLh could significantly reduce the costs of electricity supply in the studied scenario. Along with battery storage power-to-hydrogen-to-power is found to have a major role in supply of BLEL beyond 2030 as both a daily and seasonal balancing solution. Batteries are not expected to have a significant role in the provision of electricity to water electrolysers.
Thermodynamic Analysis of the Effect of Green Hydrogen Addition to a Fuel Mixture on the Steam Methane Reforming Process
Oct 2021
Publication
Steam methane (CH4–H2O) reforming in the presence of a catalyst usually nickel is the most common technology for generating synthesis gas as a feedstock in chemical synthesis and a source of pure H2 and CO. What is essential from the perspective of further gas use is the parameter describing a ratio of equilibrium concentration of hydrogen to carbon monoxide (/ = 2/). The parameter is determined by operating temperature and the initial ratio of steam concentration to methane = 2 0 /4 0 . In this paper the author presents a thermodynamic analysis of the effect of green hydrogen addition to a fuel mixture on the steam methane reforming process of gaseous phase (CH4/H2)–H2O. The thermodynamic analysis of conversion of hydrogen-enriched methane (CH4/H2)–H2O has been performed using parametric equation formalism allowing for determining the equilibrium composition of the process in progress. A thermodynamic condition of carbon precipitation in methane reforming (CH4/H2) with the gaseous phase of H2O has been interpreted. The ranges of substrate concentrations creating carbon deposition for temperature T = 1000 K have been determined based on the technologies used. The results obtained can serve as a model basis for describing the properties of steam reforming of methane and hydrogen mixture (CH4/H2)– H2O.
A Multiobjective Optimization of a Catalyst Distribution in a Methane/Steam Reforming Reactor Using a Genetic Algorithm
May 2020
Publication
The presented research focuses on an optimization design of a catalyst distribution inside a small-scale methane/steam reforming reactor. A genetic algorithm was used for the multiobjective optimization which included the search for an optimum of methane conversion rate and a minimum of the difference between highest and lowest temperatures in the reactor. For the sake of computational time the maximal number of the segment with different catalyst densities was set to be thirty in this study. During the entire optimization process every part of the reactor could be filled either with a catalyst material or non-catalytic metallic foam. In both cases the porosity and pore size was also specified. The impact of the porosity and pore size on the active reaction surface and permeability was incorporated using graph theory and three-dimensional digital material representation. Calculations start with the generation of a random set of possible reactors each with a different catalyst distribution. The algorithm calls reforming simulation over each of the reactors and after obtaining concentration and temperature fields the algorithms calculated fitness function. The properties of the best reactors are combined to generate a new population of solutions. The procedure is repeated and after meeting the coverage criteria the optimal catalyst distribution was proposed. The paper is summarized with the optimal catalyst distribution for the given size and working conditions of the system.
Enhanced Hydrogen Generation Efficiency of Methanol using Dielectric Barrier Discharge Plasma Methodology and Conducting Sea Water as an Electrode
Aug 2020
Publication
In this work methanol decomposition method has been discussed for the production of hydrogen gas with the application of plasma. A simple dielectric barrier discharge (DBD) plasma reactor was designed for this purpose with two types of electrode. The DBD plasma reactor was experimented by substituting one of the metal electrodes with feebly conducting sea water which yielded better efficiency in producing hydrogen gas. Experimental parameters such as; discharge voltage and time were varied by maintaining a discharge gap of 1.5 mm and the plasma discharge characteristics were studied. Filamentary type micro-discharges were found to be formed which was observed as numerous streamer clusters in the current waveform. Gas chromatographic study confirmed the production of hydrogen gas with residence time around 3.6 min. Although the concentration (%) of H2 was high (98.1 %) and consistent with copper electrode assembly the rate of formation and concentration was found to be the highest (98.7 %) for water electrode for specific discharge voltage. The energy efficiency was found to be 0.5 mol H2/kWh and 1.2 mol H2/kWh for metal (Cu) and water electrodes respectively. The electrode material significantly affects the plasma condition and hence the rate of hydrogen production. Compositional analysis of the water used as electrode showed a minimal change in the composition even after the completion of the experiment as compared to the untreated water. Methanol degradation study shows the presence of untreated methanol in the residue of the plasma reactor which has been confirmed from the absorption spectra.
Synergetic Effect of Multiple Phases on Hydrogen Desorption Kinetics and Cycle Durability in Ball Milled MgH2–PrF3–Al–Ni Composite
Jan 2021
Publication
A new MgH2–PrF3–Al–Ni composite was prepared by ball milling under hydrogen atmosphere. After initial dehydrogenation and rehydrogenation Pr3Al11 MgF2 PrH3 and Mg2NiH4 nanoparticles formed accompanying the main phase MgH2. The hydrogen absorption-desorption properties were measured by using a Sieverts-type apparatus. The results showed that the MgH2–PrF3–Al–Ni composite improved cycle stability and enhanced hydrogen desorption kinetics. The improvement of hydrogen absorption-desorption properties is ascribed to the synergetic effect of the in situ formed Pr3Al11 MgF2 PrH3 and Mg2NiH4 nanoparticles. This work provides an important inspiration for the improvement of hydrogen storage properties in Mg-based materials.
Setting Thresholds to Define Indifferences and Preferences in PROMETHEE for Life Cycle Sustainability Assessment of European Hydrogen Production
Jun 2021
Publication
The Life Cycle Sustainability Assessment (LCSA) is a proven method for sustainability assessment. However the interpretation phase of an LCSA is challenging because many different single results are obtained. Additionally performing a Multi-Criteria Decision Analysis (MCDA) is one way—not only for LCSA—to gain clarity about how to interpret the results. One common form of MCDAs are outranking methods. For these type of methods it becomes of utmost importance to clarify when results become preferable. Thus thresholds are commonly used to prevent decisions based on results that are actually indifferent between the analyzed options. In this paper a new approach is presented to identify and quantify such thresholds for Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE) based on uncertainty of Life Cycle Impact Assessment (LCIA) methods. Common thresholds and this new approach are discussed using a case study on finding a preferred location for sustainable industrial hydrogen production comparing three locations in European countries. The single LCSA results indicated different preferences for the environmental economic and social assessment. The application of PROMETHEE helped to find a clear solution. The comparison of the newly-specified thresholds based on LCIA uncertainty with default thresholds provided important insights of how to interpret the LCSA results regarding industrial hydrogen production.
Facile Synthesis of Palladium Phosphide Electrocatalysts and their Activity for the Hydrogen Oxidation, Hydrogen Evolutions, Oxygen Reduction and Formic Acid Oxidation Reactions
Nov 2015
Publication
We demonstrate a new approach for producing highly dispersed supported metal phosphide powders with small particle size improved stability and increased electrocatalytic activity towards some useful reactions. The approach involves a one-step conversion of metal supported on high surface area carbon to the metal phosphide utilising a very simple and scalable synthetic process. We use this approach to produce PdP2 and Pd5P2 particles dispersed on carbon with a particle size of 4.5–5.5 nm by converting a commercially available Pd/C powder. The metal phosphide catalysts were tested for the oxygen reduction hydrogen oxidation and evolution and formic acid oxidation reactions. Compared to the unconverted Pd/C material we find that alloying the P at different levels shifts oxide formation on the Pd to higher potentials leading to greater stability during cycling studies (20% more ECSA retained 5k cycles) and in thermal treatment under air. Hydrogen absorption within the PdP2 and Pd5P2 particles is enhanced. The phosphides compare favourably to the most active catalysts reported to date for formic acid oxidation especially PdP2 and there is a significant decrease in poisoning of the surface compared to Pd alone. The mechanistic changes in the reactions studied are rationalised in terms of increased water activation on the surface phosphorus atoms of the catalyst. One of the catalysts PdP2/C is tested in a fuel cell as anode and cathode catalyst and shows good performance.
Assessment of Hydrogen Direct Reduction for Fossil-free Steelmaking
Aug 2018
Publication
Climate policy objectives require zero emissions across all sectors including steelmaking. The fundamental process changes needed for reaching this target are yet relatively unexplored. In this paper we propose and assess a potential design for a fossil-free steelmaking process based on direct reduction of iron ore with hydrogen. We show that hydrogen direct reduction steelmaking needs 3.48 MWh of electricity per tonne of liquid steel mainly for the electrolyser hydrogen production. If renewable electricity is used the process will have essentially zero emissions. Total production costs are in the range of 361–640 EUR per tonne of steel and are highly sensitive to the electricity price and the amount of scrap used. Hydrogen direct reduction becomes cost competitive with an integrated steel plant at a carbon price of 34–68 EUR per tonne CO2 and electricity costs of 40 EUR/MWh. A key feature of the process is flexibility in production and electricity demand which allows for grid balancing through storage of hydrogen and hot-briquetted iron or variations in the share of scrap used.
Everything About Hydrogen Podcast: Hydrogen, Net Zero and Circularity a Perfect Syzygy!
Jul 2020
Publication
On this week's show we speak with Trevor Best CEO of Syzygy Plasmonics a Houston area startup who is a pioneer in the field of photocatalytic based hydrogen production. The company has recently closed its series A funding round. We discuss with Trevor the potential applications of the Syzygy approach and where they are aiming to engage the market first as well as his view of the evolution of the hydrogen market today. All this and more on the show!
The podcast can be found on their website
The podcast can be found on their website
Photocatalytic Production of Hydrogen from Binary Mixtures of C-3 Alcohols on Pt/TiO2: Influence of Alcohol Structure
Oct 2018
Publication
The effect of alcohol structure on photocatalytic production of H2 from C-3 alcohols was studied on 0.5% Pt/TiO2. A C-2 alcohol (ethanol) was also included for comparative purposes. For individual reactions from 10% v/v aqueous solutions of alcohols hydrogen production followed the order ethanol ≈ propan-2-ol > propan-1- ol > propane-123-triol > propane-12-diol > propane-13-diol. The process was found to be quite sensitive to the presence of additional alcohols in the reaction medium as evidenced by competitive reactions. Therefore propan-2-ol conversion was retarded in the presence of traces of the other alcohols this effect being particularly significant for vicinal diols. Additional experiments showed that adsorption of alcohols on Pt/TiO2 followed the order propane-123-triol > propane-12-diol > propane-13-diol > propan-1-ol > ethanol > propan-2-ol. Adsorption studies (DRIFT) and monitoring of reaction products showed that the main photocatalyzed process for propan-2-ol and propan-1-ol transformation is dehydrogenation to the corresponding carbonyl compound (especially for propan-2-ol both in the liquid and the gas phase). In the case of liquid-phase transformation of propan-1-ol ethane was also detected which is indicative of the dissociative mechanism to lead to the corresponding C-1 alkane. All in all competitive reactions proved to be very useful for mechanistic studies.
Hydrogen Fuel and Electricity Generation from a New Hybrid Energy System Based on Wind and Solar Energies and Alkaline Fuel Cell
Apr 2021
Publication
Excessive consumption of fossil fuels has led to depletion of reserves and environmental crises. Therefore turning to clean energy sources is essential. However these energy sources are intermittent in nature and have problems meeting long-term energy demand. The option suggested by the researchers is to use hybrid energy systems. The aim of this paper is provide the conceptual configuration of a novel energy cycle based on clean energy resources. The novel energy cycle is composed of a wind turbine solar photovoltaic field (PV) an alkaline fuel cell (AFC) a Stirling engine and an electrolyzer. Solar PV and wind turbine convert solar light energy and wind kinetic energy into electricity respectively. Then the generated electricity is fed to water electrolyzer. The electrolyzer decomposes water into oxygen and hydrogen gases by receiving electrical power. So the fuel cell inlets are provided. Next the AFC converts the chemical energy contained in hydrogen into electricity during electrochemical reactions with by-product (heat). The purpose of the introduced cycle is to generate electricity and hydrogen fuel. The relationships defined for the components of the proposed cycle are novel and is examined for the first time. Results showed that the output of the introduced cycle is 10.5 kW of electricity and its electrical efficiency is 56.9%. In addition the electrolyzer uses 9.9 kW of electricity to produce 221.3 grams per hour of hydrogen fuel. The share of the Stirling engine in the output power of the cycle is 9.85% (1033.7 W) which is obtained from the dissipated heat of the fuel cell. In addition wind turbine is capable of generating an average of 4.1 kW of electricity. However 238.6 kW of cycle exergy is destroyed. Two different scenarios are presented for solar field design.
Volumetric Analysis Technique for Analyzing the Transport Properties of Hydrogen Gas in Cylindrical-shaped Rubbery Polymers
Mar 2021
Publication
We report volumetric analysis techniques to analyze the transport properties of hydrogen dissolved in cylindrical-shaped polymers. The techniques utilize the volume measurement of the released hydrogen from rubber by gas collection in a graduated cylinder after charging sample with high-pressure hydrogen and subsequent decompression. We further improve the graduated cylinder with some modifications such as reading the electrical capacitance of the water level using electrodes and changing the sample loading position. From the measurement results the uptake (C∞) diffusion coefficient (D) and solubility (S) of hydrogen are quantified with an upgraded diffusion analysis program. These methods are applied to three cylindrical rubbers. Dual adsorption behaviors with increasing pressure are observed for all the samples. C∞ follows Henry’s law up to ~15 MPa whereas Langmuir model applies up to 90 MPa. D shows Knudsen and bulk diffusion behavior below and above pressure respectively. A COMSOL simulation is compared with experimental observations.
Economic Dispatch Model of Nuclear High-Temperature Reactor with Hydrogen Cogeneration in Electricity Market
Dec 2021
Publication
Hydrogen produced without carbon emissions could be a useful fuel as nations look to decarbonize their electricity transport and industry sectors. Using the iodine–sulfur (IS) cycle coupled with a nuclear heat source is one method for producing hydrogen without the use of fossil fuels. An economic dispatch model was developed for a nuclear-driven IS system to determine hydrogen sale prices that would make such a system profitable. The system studied is the HTTR GT/H2 a design for power and hydrogen cogeneration at the Japan Atomic Energy Agency’s High Temperature Engineering Test Reactor. This study focuses on the development of the economic model and the role that input data plays in the final calculated values. Using a historical price duration curve shows that the levelized cost of hydrogen (LCOH) or breakeven sale price of hydrogen would need to be 98.1 JPY/m3 or greater. Synthetic time histories were also used and found the LCOH to be 67.5 JPY/m3 . The price duration input was found to have a significant effect on the LCOH. As such great care should be used in these economic dispatch analyses to select reasonable input assumptions.
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.
Effect of Copper Cobalt Oxide Composition on Oxygen Evolution Electrocatalysts for Anion Exchange Membrane Water Electrolysis
Nov 2020
Publication
Copper cobalt oxide nanoparticles (CCO NPs) were synthesized as an oxygen evolution electrocatalyst via a simple co-precipitation method with the composition being controlled by altering the precursor ratio to 1:1 1:2 and 1:3 (Cu:Co) to investigate the effects of composition changes. The effect of the ratio of Cu2+/Co3+ and the degree of oxidation during the co-precipitation and annealing steps on the crystal structure morphology and electrocatalytic properties of the produced CCO NPs were studied. The CCO1:2 electrode exhibited an outstanding performance and high stability owing to the suitable electrochemical kinetics which was provided by the presence of sufficient Co3+ as active sites for oxygen evolution and the uniform sizes of the NPs in the half cell. Furthermore single cell tests were performed to confirm the possibility of using the synthesized electrocatalyst in a practical water splitting system. The CCO1:2 electrocatalyst was used as an anode to develop an anion exchange membrane water electrolyzer (AEMWE) cell. The full cell showed stable hydrogen production for 100 h with an energetic efficiency of >71%. In addition it was possible tomass produce the uniform highly active electrocatalyst for such applications through the co-precipitation method.
Controlled Biosynthesis of ZnCdS Quantum Dots with Visible-Light-Driven Photocatalytic Hydrogen Production Activity
May 2021
Publication
The development of visible-light-responsive photocatalysts with high efficiency stability and eco-friendly nature is beneficial to the large-scale application of solar hydrogen production. In this work the production of biosynthetic ternary ZnCdS photocatalysts (Eg = 2.35–2.72 eV) by sulfate-reducing bacteria (SRB) under mild conditions was carried out for the first time. The huge amount of biogenic S2− and inherent extracellular proteins (EPs) secreted by SRB are important components of rapid extracellular biosynthesis. The ternary ZnCdS QDs at different molar ratios of Zn2+and Cd2+ from 15:1 to 1:1 were monodisperse spheres with good crystallinity and average crystallite size of 6.12 nm independent of the molar ratio of Cd2+ to Zn2+. All the ZnCdS QDs had remarkable photocatalytic activity and stability for hydrogen evolution under visible light without noble metal cocatalysts. Especially ZnCdS QDs at Zn/Cd = 3:1 showed the highest H2 production activity of 3.752 mmol·h−1·g−1. This excellent performance was due to the high absorption of visible light the high specific surface area and the lower recombination rate between photoexcited electrons and holes. The adhered inherent EPs on the ZnCdS QDs slowed down the photocorrosion and improved the stability in photocatalytic hydrogen evolution. This study provides a new direction for solar hydrogen production.
A Flexible Analytical Model for Operational Investigation of Solar Hydrogen Plants
Nov 2021
Publication
Hydrogen will become a dominant energy carrier in the future and the efficiency and lifetime cost of its production through water electrolysis is a major research focus. Alongside efforts to offer optimum solutions through plant design and sizing it is also necessary to develop a flexible virtualised replica of renewable hydrogen plants that not only models compatibility with the “plug-and-play” nature of many facilities but that also identifies key elements for optimisation of system operation. This study presents a model for a renewable hydrogen production plant based on real-time historical and present-day datasets of PV connected to a virtualised grid-connected AC microgrid comprising different technologies of batteries electrolysers and fuel cells. Mathematical models for each technology were developed from chemical and physical metrics of the plant. The virtualised replica is the first step toward the implementation of a digital twin of the system and accurate validation of the system behaviour when updated with real-time data. As a case study a solar hydrogen pilot plant consisting of a 60 kW Solar PV a 40 kW PEM electrolyser a 15 kW LIB battery and a 5 kW PEM fuel cell were simulated and analysed. Two effective operational factors on the plant's performance are defined: (i) electrolyser power settings to determine appropriate hydrogen production over twilight periods and/or overnight and (ii) a user-defined minimum threshold for battery state of charge to prevent charge depletion overnight if the electrolyser load is higher than its capacity. The objective of this modelling is to maximise hydrogen yield while both loss of power supply probability (LPSP) and microgrid excess power are minimised. This analysis determined: (i) a hydrogen yield of 38e39% from solar DC energy to hydrogen energy produced (ii) an LPSP <2.6 104 and (iii) < 2% renewable energy lost to the grid as excess electricity for the case study.
Global Status of CCS 2021: CCS Accelerating to Net Zero
Oct 2021
Publication
Carbon capture and storage (CCS) continues to make significant progress around the world against a backdrop of greater climate action from countries and private companies. The Global Status of CCS 2021 demonstrates the critical role of CCS as nations and industry accelerate to net-zero.<br/>The report provides detailed analyses of the global project pipeline international policy finance and emerging trends. In addition four regional overviews highlight the rapid development of CCS across North America Asia Pacific Europe and nearby regions and the Gulf Cooperation Council states.
Pulsed-Supplied Water Electrolysis via Two-Switch Converter for PV Capacity Firming
Mar 2022
Publication
Hydrogen constitutes the only carbon-free fuel that can be used for energy conversion producing water as the only by-product. With water being one of the most abundant and inexhaustible raw materials in the world and the required electricity input being provided by renewable resources the produced hydrogen via water electrolysis constitutes a green pathway towards sustainability. In this work a hybrid PV power-to-hydrogen storage and fuel cell system is proposed to satisfy the domestic load of a residential building. Identifying alkaline as a mandatory electrolysis technology the performance of alkaline electrolysis cells is assessed considering the inclusion of a two-switch buck-boost converter. Following a comprehensive formulation with respect to each distinguished system component the balance condition at DC and AC buses is determined. The proposed configuration is evaluated taking into account PV systems of different ratings namely 3 kW 5 kW and 7 kW. Based on actual data relating to both PV generation and domestic load for the year 2020 the obtained results from the annual simulations are compared with feed-in tariff and net-metering schemes. According to the results PV capacity firming is achieved creating great opportunities for autonomy enhancement not only for electricity but also in other energy sectors.
Ammonia as a Carrier for Hydrogen Production by using Lanthanum Based Perovskites
Sep 2021
Publication
LaNiO3 and LaCoO3 perovskites synthesized by self-combustion were characterised and studied in the ammonia decomposition reaction for obtaining hydrogen. Both the fuel to metal nitrates molar ratio and calcination temperature were found to be crucial to synthesize perovskites by self-combustion. Moreover generating non-precursor species during synthesis and small metal size were two factors which significantly influenced catalytic activity. Hence with a citric acid to metal nitrates molar ratio equal to one a LaNiO3 perovskite was obtained with suitable physicochemical properties (specific surface area lower impurities and basicity). In addition a lower calcination temperature (650 ◦C) resulted in small and well-dispersed Ni0 crystallite size after reduction which in turn promoted the catalytic transformation of ammonia into hydrogen. For cobalt perovskites calcination temperature below 900 ◦C did not have a significant influence on the size of the metallic cobalt crystallite size. The nickel and cobalt perovskite-derived catalysts calcined at 650 ◦C and 750 ◦C respectively yielded excellent H2 production from ammonia decomposition. In particular at 450 ◦C almost 100% of the ammonia was converted over the LaNiO3 under study. Furthermore these materials displayed admirable performance and stability after one day of reaction.
Australian Hydrogen Hubs Study
Nov 2019
Publication
Arup have conducted interviews with targeted industry and government stakeholders to gather data and perspectives to support the development of this study. Arup have also utilised private and publicly available data sources building on recent work undertaken by Geoscience Australia and Deloitte and the comprehensive stakeholder engagement process to inform our research. This study considers the supply chain and infrastructure requirements to support the development of export and domestic hubs. The study aims to provide a succinct “Hydrogen Hubs” report for presentation to the hydrogen working group.
The hydrogen supply chain infrastructure required to produce hydrogen for export and domestic hubs was identified along with feedback from the stakeholder engagement process. These infrastructure requirements can be used to determine the factors for assessing export and domestic hub opportunities. Hydrogen production pathways transportation mechanisms and uses were also further evaluated to identify how hubs can be used to balance supply and demand of hydrogen.
A preliminary list of current or anticipated locations has been developed through desktop research Arup project knowledge and the stakeholder consultation process. Over 30 potential hydrogen export locations have been identified in Australia through desktop research and the stakeholder survey and consultation process. In addition to establishing export hubs the creation of domestic demand hubs will be essential to the development of an Australian hydrogen economy. It is for this reason that a list of criteria has been developed for stakeholders to consider in the siting and design of hydrogen hubs. The key considerations explored are based on demand supply chain infrastructure and investment and policy areas.
Based on these considerations a list of criteria were developed to assess the viability of export and domestic hydrogen hubs. Criteria relevant to assessing the suitability of export and domestic hubs include:
A framework that includes the assessment criteria has been developed to aid decision making rather than recommending specific locations that would be most appropriate for a hub. This is because there are so many dynamic factors that go into selecting a location of a hydrogen hub that it is not appropriate to be overly prescriptive or prevent stakeholders from selecting the best location themselves or from the market making decisions based on its own research and knowledge. The developed framework rather provides information and support to enable these decision-making processes.
The hydrogen supply chain infrastructure required to produce hydrogen for export and domestic hubs was identified along with feedback from the stakeholder engagement process. These infrastructure requirements can be used to determine the factors for assessing export and domestic hub opportunities. Hydrogen production pathways transportation mechanisms and uses were also further evaluated to identify how hubs can be used to balance supply and demand of hydrogen.
A preliminary list of current or anticipated locations has been developed through desktop research Arup project knowledge and the stakeholder consultation process. Over 30 potential hydrogen export locations have been identified in Australia through desktop research and the stakeholder survey and consultation process. In addition to establishing export hubs the creation of domestic demand hubs will be essential to the development of an Australian hydrogen economy. It is for this reason that a list of criteria has been developed for stakeholders to consider in the siting and design of hydrogen hubs. The key considerations explored are based on demand supply chain infrastructure and investment and policy areas.
Based on these considerations a list of criteria were developed to assess the viability of export and domestic hydrogen hubs. Criteria relevant to assessing the suitability of export and domestic hubs include:
- Health and safety provisions;
- Environmental considerations;
- Economic and social considerations;
- Land availability with appropriate zoning and buffer distances & ownership (new terminals storage solar PV industries etc.);•
- Availability of gas pipeline infrastructure;
- Availability of electricity grid connectivity backup energy supply or co-location of renewables;
- Road & rail infrastructure (site access);
- Community and environmental concerns and weather. Social licence consideration;
- Berths (berthing depth ship storage loading facilities existing LNG and/or petroleum infrastructure etc.);
- Port potential (current capacity & occupancy expandability & scalability);
- Availability of or potential for skilled workers (construction & operation);
- Availability of or potential for water (recycled & desalinated);
- Opportunity for co-location with industrial ammonia production and future industrial opportunities;
- Interest (projects priority ports state development areas politics etc.);
- Shipping distance to target market (Japan & South Korea);
- Availability of demand-based infrastructure (i.e. refuelling stations).
A framework that includes the assessment criteria has been developed to aid decision making rather than recommending specific locations that would be most appropriate for a hub. This is because there are so many dynamic factors that go into selecting a location of a hydrogen hub that it is not appropriate to be overly prescriptive or prevent stakeholders from selecting the best location themselves or from the market making decisions based on its own research and knowledge. The developed framework rather provides information and support to enable these decision-making processes.
Co-production of Hydrogen and Power from Black Liquor Via Supercritical Water Gasification, Chemical Looping and Power Generation
Mar 2019
Publication
An integrated system to harvest efficiently the energy from the waste of pulp mill industry which is black liquor (BL) is proposed and evaluated. The proposed system consists of the supercritical water gasification (SCWG) of BL syngas chemical looping and power generation. To minimize the exergy loss throughout the system and to optimize the energy efficiency process design and integration is conducted by employing the principles of exergy recovery and process integration methods. Hydrogen is set as the main output while power is produced by utilizing the heat generated throughout the process. Process simulation is conducted using a steady state process simulator Aspen Plus. Energy efficiency is defined into three categories: hydrogen production efficiency power generation efficiency and total energy efficiency. From process simulation both of the integrated systems show very high total energy efficiency of about 73%.
Electrochemical Hydrogen Production Powered by PVCSP Hybrid Power Plants A Modelling Approach for Cost Optimal System Design
Jun 2021
Publication
Global trade of green hydrogen will probably become a vital factor in reaching climate neutrality. The sunbelt of the Earth has a great potential for large-scale hydrogen production. One promising pathway to solar hydrogen is to use economically priced electricity from photovoltaics (PV) for electrochemical water splitting. However storing electricity with batteries is still expensive and without storage only a small operating capacity of electrolyser systems can be reached. Combining PV with concentrated solar power (CSP) and thermal energy storage (TES) seems a good pathway to reach more electrolyser full load hours and thereby lower levelized costs of hydrogen (LCOH). This work introduces an energy system model for finding cost-optimal designs of such PV/CSP hybrid hydrogen production plants based on a global optimization algorithm. The model includes an operational strategy which improves the interplay between PV and CSP part allowing also to store PV surplus electricity as heat. An exemplary study for stand-alone hydrogen production with an alkaline electrolyser (AEL) system is carried out. Three different locations with different solar resources are considered regarding the total installed costs (TIC) to obtain realistic LCOH values. The study shows that a combination of PV and CSP is an auspicious concept for large-scale solar hydrogen production leading to lower costs than using one of the technologies on its own. For today’s PV and CSP costs minimum levelized costs of hydrogen of 4.04 USD/kg were determined for a plant located in Ouarzazate (Morocco). Considering the foreseen decrease in PV and CSP costs until 2030 cuts the LCOH to 3.09 USD/kg while still a combination of PV and CSP is the most economic system.
Economic Conditions for Developing Hydrogen Production Based on Coal Gasification with Carbon Capture and Storage in Poland
Sep 2020
Publication
This study documents the results of economic assessment concerning four variants of coal gasification to hydrogen in a shell reactor. That assessment has been made using discounting methods (NPV: net present value IRR: internal rate of return) as well as indicators based on a free cash flow to firm (FCFF) approach. Additionally sensitivity analysis has been carried out along with scenario analysis in current market conditions concerning prices of hard coal lignite hydrogen and CO2 allowances as well as capital expenditures and costs related to carbon capture and storage (CCS) systems. Based on NPV results a negative economic assessment has been obtained for all the analyzed variants varying within the range of EUR −903 to −142 million although the variants based on hard coal achieved a positive IRR (5.1–5.7%) but lower than the assumed discount rates. In Polish conditions the gasification of lignite seems to be unprofitable in the assumed scale of total investment outlays and the current price of coal feedstock. The sensitivity analyses indicate that at least a 20% increase of hydrogen price would be required or a similar reduction of capital expenditures (CAPEX) and costs of operation for the best variant to make NPV positive. Analyses have also indicated that on the economic basis only the prices of CO2 allowances exceeding EUR 40/Mg (EUR 52/Mg for lignite) would generate savings due to the availability of CCS systems.
Hydrogen Production on Demand by Redox-mediated Electrocatalysis: A Kinetic Study
Aug 2020
Publication
Producing hydrogen from water using a redox mediator on solid electrocatalyst particles in a reactor offers several advantages over classical electrolysis in terms of safety membrane degradation purity and flexibility. Herein vanadium-mediated hydrogen evolution on a commercial and low-cost Mo2C electrocatalyst is studied through the development of a reaction kinetics model. Based on a proposed mechanistic reaction scheme we established a kinetic rate law dependent on the concentration of V2+ the state-of-charge of the vanadium electrolyte from a vanadium redox flow battery and the amount of available catalytic sites on solid Mo2C. Kinetic experiments in transient conditions reveals a first-order dependence on both the concentration of V2+ and the concentration of catalytic active sites and a power law with an exponential factor of 0.57 was measured on the molar ratio V2+/V3+ i.e. on the electrochemical driving force generated on the Mo2C particles. The kinetic rate law was validated by studying the rate of reaction in steady-state conditions using a specially developed rotating ring-disk device (RRD) methodology. The kinetic model was demonstrated to be a useful tool to predict the hydrogen production via the chemical oxidation of V2+ over Mo2C at low pH (> 1 M H2SO4). For a perspective the model was implemented in a semi-batch reactor. The simulations highlight the optimal state-of-charge (SOC) to carry out the reaction in an efficient way for a given demand in hydrogen.
Water Photo-Electrooxidation Using Mats of TiO2 Nanorods, Surface Sensitized by a Metal–Organic Framework of Nickel and 1,2-Benzene Dicarboxylic Acid
Apr 2021
Publication
Photoanodes comprising a transparent glass substrate coated with a thin conductive film of fluorine-doped tin oxide (FTO) and a thin layer of a photoactive phase have been fabricated and tested with regard to the photo-electro-oxidation of water into molecular oxygen. The photoactive layer was made of a mat of TiO2 nanorods (TDNRs) of micrometric thickness. Individual nanorods were successfully photosensitized with nanoparticles of a metal–organic framework (MOF) of nickel and 12-benzene dicarboxylic acid (BDCA). Detailed microstructural information was obtained from SEM and TEM analysis. The chemical composition of the active layer was determined by XRD XPS and FTIR analysis. Optical properties were determined by UV–Vis spectroscopy. The water photooxidation activity was evaluated by linear sweep voltammetry and the robustness was assessed by chrono-amperometry. The OER (oxygen evolution reaction) photo-activity of these photoelectrodes was found to be directly related to the amount of MOF deposited on the TiO2 nanorods and was therefore maximized by adjusting the MOF content. The microscopic reaction mechanism which controls the photoactivity of these photoelectrodes was analyzed by photo-electrochemical impedance spectroscopy. Microscopic rate parameters are reported. These results contribute to the development and characterization of MOF-sensitized OER photoanodes.
The Development of an Assessment Framework to Determine the Technical Hydrogen Production Potential from Wind and Solar Energy
Jun 2022
Publication
Electrolytic hydrogen produced from wind and solar energy is considered a long-term option for multi-sectoral decarbonization. The study objective is to develop a framework for assessing country-level hydrogen technical potential from wind and solar energy. We apply locational suitability and zonal statistical analyses methods in a geographic information system-based environment to derive granular insights on non-captive technically exploitable hydrogen potential in high-resource locations. Seven setback factors were considered for locational suitability and integrated with modules developed for evaluating the wind and solar resource penetration from open-source theoretical renewable resource geospatial data and electricity-to-hydrogen conversion analyses. The technique applied in this study would be a relevant contribution to determining national and regional-wide electrolytic hydrogen production potentials in other jurisdictions with requisite adjustments to data and technical constraints. The results from the case study country Canada – a major hydrogen-producing country – show that the technical hydrogen potentials from wind and solar energy are approximately 1897 and 448 million metric tonnes per year respectively at least 6.3 times greater than global hydrogen demand in 2019. When we integrated locational data on enabling infrastructure we discovered that the lack of access to power transmission lines in low-population-density areas of the country significantly reduces the exploitable wind- and solar-based hydrogen potential by over 80% and 6% respectively. The findings of this study show that in the absence of spatial data on infrastructural constraints the exploitable hydrogen potential in a jurisdiction can be overestimated leading to improper guidance for policy and decision-makers.
Photoelectrochemical Hydrogen Production by Screen-Printed Copper Oxide Electrodes
May 2021
Publication
In this work copper oxides-based photocathodes for photoelectrochemical cells (PEC) were produced for the first time by screen printing. A total 7 × 10−3 g/m2 glycerine trioleate was found as optimum deflocculant amount to assure stable and homogeneous inks based on CuO nano-powder. The inks were formulated considering different binder amounts and deposited producing films with homogenous thickness microstructure and roughness. The as-produced films were thermally treated to obtain Cu2O- and Cu2O/CuO-based electrodes. The increased porosity obtained by adding higher amounts of binder in the ink positively affected the electron transfer from the surface of the electrode to the electrolyte thus increasing the corresponding photocurrent values. Moreover the Cu2O/CuO system showed a higher charge carrier and photocurrent density than the Cu2O-based one. The mixed Cu2O/CuO films allowed the most significant hydrogen production especially in slightly acid reaction conditions.
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.
Evaluation of a New Combined Energy System Performance to Produce Electricity and Hydrogen with Energy Storage Option
Mar 2021
Publication
According to new findings the use of alternative energy sources such as wind energy is needed to supply the energy demand of future generations. On the other hand combined renewable energy systems can be more efficient than their stand-alone systems. Therefore clean energy-based hybrid energy systems can be a suitable solution for fossil fuels. However for their widespread commercialization more detailed and powerful studies are needed. On the other hand in order to attain sustainable development for the use of renewable energy sources due to their nature energy storage is required. The motivation of this study is introduce and examine a new energy system performance for the production of electricity and hydrogen fuel as well as energy storage. So this paper presents the energy and exergy operation of a hybrid wind turbine water electrolyzer and Pumped-hydro-compressed air system. The electricity produced by the wind turbine is used to produce hydrogen fuel in electrolyzer and the excess energy is stored using the storage system. It was found that the electrolyzer needed 512.6 W of electricity to generate 5 mol/h of hydrogen fuel which was supplied by a 10 kW-wind turbine. In such a context the efficiency of the process was 74.93%. Furthermore on average the isothermal process requires 17.53% less storage capacity than the isentropic process. The effect of key parameters such as rate of hydrogen fuel production operating pressures wind speed and components efficiency on the process operation is also examined.
Modeling Photovoltaic-electrochemical Water Splitting Devices for the Production of Hydrogen Under Real Working Conditions
Jan 2022
Publication
Photoelectrochemical splitting of water is potentially a sustainable and affordable solution to produce hydrogen from sun light. Given the infancy stage of technology development it is important to compare the different experimental concepts and identify the most promising routes. The performance of photoelectrochemical devices is typically measured and reported under ideal irradiation conditions i.e. 1 sun. However real-life operating conditions are very different and are varying in time according to daily and seasonal cycles. In this work we present an equivalent circuit model for computing the steady state performance of photoelectrochemical cells. The model allows for a computationally efficient yet precise prediction of the system performance and a comparison of different devices working in real operating conditions. To this end five different photo-electrochemical devices are modeled using experimental results from literature. The calculated performance shows good agreement with experimental data of the different devices. Furthermore the model is extended to include the effect of illumination and tilt angle on the hydrogen production efficiency. The resulting model is used to compare the devices for different locations with high and low average illumination and different tilt angles. The results show that including real illumination data has a considerable impact on the efficiency of the PV-EC device. The yearly average solar-to-hydrogen efficiency is significantly lower than the ideal one. Moreover it is dependent on the tilt angle whose optimal value for European-like latitude is around 40. Notably we also show that the most performing device through the whole year might not necessarily be the one with highest sun-to-hydrogen efficiency for one-sun illumination.
The Role of Hydrogen in the Transition from a Petroleum Economy to a Low-carbon Society
Jun 2021
Publication
A radical decarbonization pathway for the Norwegian society towards 2050 is presented. The paper focuses on the role of hydrogen in the transition when present Norwegian petroleum export is gradually phased out. The study is in line with EU initiatives to secure cooperation opportunities with neighbouring countries to establish an international hydrogen market. Three analytical perspectives are combined. The first uses energy models to investigate the role of hydrogen in an energy and power market perspective without considering hydrogen export. The second uses an economic equilibrium model to examine the potential role of hydrogen export in value creation. The third analysis is a socio-technical case study on the drivers and barriers for hydrogen production in Norway. Main conclusions are that access to renewable power and hydrogen are prerequisites for decarbonization of transport and industrial sectors in Norway and that hydrogen is a key to maintain a high level of economic activity. Structural changes in the economy impacts of new technologies and key enablers and barriers in this transition are discussed.
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.
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.
Two-Dimensional Photocatalysts for Energy and Environmental Applications
Jun 2022
Publication
The depletion of fossil fuels and onset of global warming dictate the achievement of efficient technologies for clean and renewable energy sources. The conversion of solar energy into chemical energy plays a vital role both in energy production and environmental protection. A photocatalytic approach for H2 production and CO2 reduction has been identified as a promising alternative for clean energy production and CO2 conversion. In this process the most critical parameter that controls efficiency is the development of a photocatalyst. Two-dimensional nanomaterials have gained considerable attention due to the unique properties that arise from their morphology. In this paper examples on the development of different 2D structures as photocatalysts in H2 production and CO2 reduction are discussed and a perspective on the challenges and required improvements is given.
Everything About Hydrogen Podcast: Reaching for the Stars
Mar 2023
Publication
Today Everything About Hydrogen had a chance to speak with Paul Barrett the CEO of Hysata and dig into what makes this electrolysis company different.
The podcast can be found on their website.
The podcast can be found on their website.
Utilization of Food Waste for Hydrogen-based Power Generation: Evidence from Four Cities in Ghana
Mar 2023
Publication
Hydrogen gas will be an essential energy carrier for global energy systems in the future. However non-renewable sources account for 96% of the production. Food wastes have high hydrogen generation potential which can positively influence global production and reduce greenhouse gas (GHG) emissions. The study evaluates the potential of food waste hydrogen-based power generation through biogas steam reforming and its environmental and economic impact in major Ghanaian cities. The results highlight that the annual hydrogen generation in Kumasi had the highest share of 40.73 kt followed by Accra with 31.62 kt while the least potential was in Tamale (3.41 kt). About 2073.38 kt was generated in all the major cities. Hydrogen output is predicted to increase from 54.61 kt in 2007 to 119.80 kt by 2030. Kumasi produced 977.54 kt of hydrogen throughout the 24-year period followed by Accra with 759.76 kt Secondi-Takoradi with 255.23 kt and Tamale with 81.85 kt. According to the current study Kumasi had the largest percentage contribution of hydrogen (47.15%) followed by Accra (36.60%) Secondi-Takoradi (12.31%) and Tamale (3.95%). The annual power generation potential in Kumasi and Accra was 73.24 GWh and 56.85 GWh. Kumasi and Accra could offset 8.19% and 6.36% of Ghana's electricity consumption. The total electricity potential of 3728.35 GWh could displace 17.37% of Ghana's power consumption. This electricity generated had a fossil diesel displacement capacity of 1125.90 ML and could reduce GHG emissions by 3060.20 kt CO2 eq. Based on the findings the total GHG savings could offset 8.13% of Ghana's carbon emissions. The cost of power generation from hydrogen is $ 0.074/kWh with an annual positive net present value of $ 658.80 million and a benefit-to-cost ratio of 3.43. The study lays the foundation and opens policy windows for sustainable hydrogen power generation in Ghana and other African countries.
From Biogas to Hydrogen: A Techno-Economic Study on the Production of Turquoise Hydrogen and Solid Carbons
Sep 2022
Publication
Biogas is a renewable feedstock that can be used to produce hydrogen through the decomposition of biomethane. However the economics of the process are not well studied and understood especially in cases where solid carbons are also produced and which have a detrimental effect on the performance of the catalysts. The scale as well as product diversification of a biogas plant to produce hydrogen and other value-added carbons plays a crucial role in determining the feasibility of biogasto-hydrogen projects. Through a techno-economic study using the discounted cash flow method it has been shown that there are no feasible sizes of plants that can produce hydrogen at the target price of USD 3/kg or lower. However for self-funded anaerobic digestor plants retrofitting modular units for hydrogen production would only make financial sense at biogas production capacities of more than 412 m3/h. A sensitivity analysis has also shown that the cost competitiveness is dependent on the type of carbon formed and low-grade carbon black has a negative effect on economic feasibility. Hydrogen produced from biogas would thus not be able to compete with grey hydrogen production but rather with current green hydrogen production costs.
Dynamic Investigation and Optimization of a Solar‐Based Unit for Power and Green Hydrogen Production: A Case Study of the Greek Island, Kythnos
Nov 2022
Publication
The aim of the present work is the analysis of a solar‐driven unit that is located on the non‐interconnected island of Kythnos Greece that can produce electricity and green hydrogen. More specifically solar energy is exploited by parabolic trough collectors and the produced heat is stored in a thermal energy storage tank. Additionally an organic Rankine unit is incorporated to generate electricity which contributes to covering the island’s demand in a clean and renewable way. When the power cannot be absorbed by the local grid it can be provided to a water electrolyzer; therefore the excess electricity is stored in the form of hydrogen. The produced hydrogen amount is compressed afterward stored in tanks and then finally can be utilized as a fuel to meet other important needs such as powering vehicles or ferries. The installation is simulated parametrically and optimized on dynamic conditions in terms of energy exergy and finance. According to the results considering a base electrical load of 75 kW the annual energy and exergy efficiencies are found at 14.52% and 15.48% respectively while the payback period of the system is deter‐ mined at 6.73 years and the net present value is equal to EUR 1073384.
Optimization of Small-Scale Hydrogen Production with Membrane Reactors
Mar 2023
Publication
In the pathway towards decarbonization hydrogen can provide valid support in different sectors such as transportation iron and steel industries and domestic heating concurrently reducing air pollution. Thanks to its versatility hydrogen can be produced in different ways among which steam reforming of natural gas is still the most commonly used method. Today less than 0.7% of global hydrogen production can be considered low-carbon-emission. Among the various solutions under investigation for low-carbon hydrogen production membrane reactor technology has the potential especially at a small scale to efficiently convert biogas into green hydrogen leading to a substantial process intensification. Fluidized bed membrane reactors for autothermal reforming of biogas have reached industrial maturity. Reliable modelling support is thus necessary to develop their full potential. In this work a mathematical model of the reactor is used to provide guidelines for their design and operations in off-design conditions. The analysis shows the influence of temperature pressures catalyst and steam amounts and inlet temperature. Moreover the influence of different membrane lengths numbers and pitches is investigated. From the results guidelines are provided to properly design the geometry to obtain a set recovery factor value and hydrogen production. For a given reactor geometry and fluidization velocity operating the reactor at 12 bar and the permeate-side pressure of 0.1 bar while increasing reactor temperature from 450 to 500 °C leads to an increase of 33% in hydrogen production and about 40% in HRF. At a reactor temperature of 500 °C going from 8 to 20 bar inside the reactor doubled hydrogen production with a loss in recovery factor of about 16%. With the reactor at 12 bar a vacuum pressure of 0.5 bar reduces hydrogen production by 43% and HRF by 45%. With the given catalyst it is sufficient to have only 20% of solids filled into the reactor being catalytic particles. With the fixed operating conditions it is worth mentioning that by adding membranes and maintaining the same spacing it is possible to increase hydrogen production proportionally to the membrane area maintaining the same HRF.
Methane Pyrolysis for CO2-Free H2 Production: A Green Process to Overcome Renewable Energies Unsteadiness
Aug 2020
Publication
The Carbon2Chem project aims to convert exhaust gases from the steel industry into chemicals such as methanol to reduce CO2 emissions. Here H2 is required for the conversion of CO2 into methanol. Although much effort is put to produce H2 from renewables the use of fossil fuels especially natural gas seems to be fundamental in the short term. For this reason the development of clean technologies for the processing of natural gas with a low environmental impact has become a topic of utmost importance. In this context methane pyrolysis has received special attention to produce CO2-free H2.
A Study of Thermoelectric Generation Coupled with Methanol Steam Reforming for Hydrogen Production
Nov 2022
Publication
Waste heat recovery was considered as a promising candidate for energy conservation and emission reduction. Methanol steam reforming was considered to be an effective means for hydrogen production because of its advantages. In this work a micro reactor was constructed and thermoelectric generation coupled with hydrogen production from methanol steam reforming was innovatively used to recycle waste heat which was simulated by hot air from a hot air gun. The waste heat was converted into electricity and hydrogen at the same time. The characteristic of thermoelectric generation coupled with methanol steam reforming was investigated. It was experimentally verified that both the hydrogen production rate and methanol conversion increased with the increasing inlet temperature but thermal efficiency increased firstly and then decreased with the increasing temperature. The methanol steam reforming could effectively maintain cold side temperature distribution of thermoelectric generation. In the case of the thermoelectric module (1) the highest temperature difference of 37 ◦C was determined and the maximum open circuit voltage of 2 V was observed. The highest methanol conversion of 64.26% was achieved at a space velocity of 0.98 h−1 when the temperature was 543 K comprehensively considering the CO content and thermal efficiency.
Distinct facets to enhance the process of hydrogen production via methanol steam reforming—A review
Jan 2022
Publication
Methanol steam reforming manifests great potential for generating hydrogen owing to its lower reaction temperature (200–300 °C) and higher hydrogen/carbon ratio comparing with ethanol and methane reforming. In this case methanol steam reforming is applied in various renewable energy systems to assist the energy conversion and improve the system efficiency. The performance of methanol steam reforming reaction strongly depends on the catalysts and reactor structure. In this paper the development of the copper-based the noble metal–based and the nanomaterial catalysts were summarized by analyzing the effects of different modification methods which indicates that cutting the cost and simplifying the manufacturing process are the future goal of catalyst modification. Moreover the reaction mechanism of different catalyst type was discussed. For the reactor performance conventional miniature micro and membrane reactors were discussed and compared where conventional reactor with high CO tolerance is more suitable for industrial application while membrane reactor with high H2 purity and compact structure is ideal for fuel cell technology. The integration of the methanol steam reforming system into renewable power systems was reviewed as well. Methanol steam reforming technology is of great potential in exhaust heat recovery cogeneration system and other renewable energy field where more comprehensive research should be performed.
Determination of the Optimal Power Ratio between Electrolysis and Renewable Energy to Investigate the Effects on the Hydrogen Production Costs
Sep 2022
Publication
Green hydrogen via renewable powered electrolysis has a high relevance in decarbonization and supply security. Achieving economically competitive hydrogen production costs is a major challenge in times of an energy price crisis. Our objective is to show the economically optimal installed capacity of electrolysers in relation to wind and solar power so swift and credible statements can be made regarding the system design. The ratio between renewable generation and electrolysis power as well as scaling effects operating behaviour and development of costs are considered. Hydrogen production costs are calculated for four exemplary real PV and wind sites and different ratios of electrolysis to renewable power for the year 2020. The ideal ratio for PV systems is between 14% and 73% and for wind between 3.3% and 143% for low and high full load hours. The lowest hydrogen production costs are identified at 2.53 €/kg for 50 MW wind power and 72 MW electrolysis power. The results provide plant constructors the possibility to create a cost-optimized design via an optimum ratio of electrolysis to renewable capacity. Therefore the procedures for planning and dimensioning of selected systems can be drastically simplified.
Feasibility Study of "CO2 Free Hydrogen Chain" Utilizing Australian Brown Coal Linked with CCS
Nov 2012
Publication
We had investigated feasible measures to reduce CO2 emission and came to conclusion that introduction of new fuel such as hydrogen with near zero CO2 emission is required for achieving Japan’s commitment of 80% CO2 reduction by 2050. Under this background we are proposing and aiming to realize “CO2 free hydrogen chain” utilizing Australian brown coal linked with CCS. In this chain hydrogen produced from brown coal is liquefied and transported to Japan by liquid hydrogen carrier. We have conducted feasibility study of commercial scale “CO2 free hydrogen chain” whose result shows the chain is technically and economically feasible.
Exploring Key Operational Factors for Improving Hydrogen Production in a Pilot-scale Microbial Electrolysis Cell Treating Urban Wastewater
Jun 2023
Publication
Bioelectrochemical systems (BES) are becoming popular technologies with a plethora of applications in the environmental field. However research on the scale-up of these systems is scarce. To understand the limiting factors of hydrogen production in microbial electrolysis cell (MEC) at pilot scale a 135 L MEC was operated for six months under a wide range of operational conditions: applied potential [0.8-1.1 V] hydraulic residence time [1.1-3.9 d] and temperature [18-30 ºC] using three types of wastewater; synthetic (900 mg CODs L-1) raw urban wastewater (200 mg CODs L-1) and urban wastewater amended with acetate (1000 mg CODs L-1). The synthetic wastewater yielded the maximum current density (1.23 A m-2) and hydrogen production (0.1 m3 m-3 d-1) ever reported in a pilot scale MEC with a cathodic recovery of 70% and a coulombic efficiency of 27%. In contrast the use of low COD urban wastewater limited the plant performance. Interestingly it was possible to improve hydrogen production by reducing the hydraulic residence time finding the optimal applied potential or increasing the temperature. Further the pilot plant demonstrated a robust capacity to remove the organic matter present in the wastewater under different conditions with removal efficiencies above 70%. This study shows improved results compared to similar MEC pilot plants treating domestic wastewater in terms of hydrogen production and treatment efficiency and also compares its performance against conventional activated sludge processes.
Energy Recovery from Wastewater in Mexico: A Systematic Review
Feb 2023
Publication
The usage of fossil fuels to generate energy and the lack of wastewater treatment in Mexico are two issues that can be addressed at the same time while developing wastewater treatment technologies that incorporate energy recovery in their process train. We carried out a systematic review based on the PRISMA methodology to identify and review studies regarding energy recovery using wastewater as a substrate in Mexico. Peer-reviewed papers were identified through Scopus Web of Knowledge and Google Scholar using a timeframe of 22 years that represented from 2000 to 2022. After applying the selection criteria we identified 31 studies to be included in the final review starting from 2007. The kind of energy product type of technology used substrate wastewater amount of energy produced and main parameters for the operation of the technology were extracted from the papers. The results show that methane is the most researched energy recovery product from wastewater followed by hydrogen and electricity and the technology used to archive it is an up-flow anaerobic sludge bed (UASB) reactor to produce methane and hydrogen. In addition microbial fuel cells (MFCs) were preferred to produce electricity. According to our data more energy per kgCOD removed could be obtained with methane-recovering technologies in the Mexican peer-reviewed studies compared with hydrogen recovery and electricity production.
Hubs and Clusters Approach to Unlock the Development of Carbon Capture and Storage - Case Study in Spain
Jul 2021
Publication
Xiaolong Sun,
Juan Alcalde,
Mahdi Bakhtbidar,
Javier Elío,
Víctor Vilarrasa,
Jacobo Canal,
Julio Ballesteros,
Niklas Heinemann,
Stuart Haszeldine,
Andrew Cavanagh,
David Vega-Maza,
Fernando Rubiera,
Roberto Martínez-Orio,
Gareth Johnson,
Ramon Carbonell,
Ignacio Marzan,
Anna Travé and
Enrique Gomez-Rivas
Many countries have assigned an indispensable role for carbon capture and storage (CCS) in their national climate change mitigation pathways. However CCS deployment has stalled in most countries with only limited commercial projects realised mainly in hydrocarbon-rich countries for enhanced oil recovery. If the Paris Agreement is to be met then this progress must be replicated widely including hydrocarbon-limited countries. In this study we present a novel source-to-sink assessment methodology based on a hubs and clusters approach to identify favourable regions for CCS deployment and attract renewed public and political interest in viable deployment pathways. Here we apply this methodology to Spain where fifteen emission hubs from both the power and the hard-to-abate industrial sectors are identified as potential CO2 sources. A priority storage structure and two reserves for each hub are selected based on screening and ranking processes using a multi-criteria decision-making method. The priority source-to-sink clusters are identified indicating four potential development regions with the North-Western and North-Eastern Spain recognised as priority regions due to resilience provided by different types of CO2 sources and geological structures. Up to 68.7 Mt CO2 per year comprising around 21% of Spanish emissions can be connected to clusters linked to feasible storage. CCS especially in the hard-to-abate sector and in combination with other low-carbon energies (e.g. blue hydrogen and bioenergy) remains a significant and unavoidable contributor to the Paris Agreement’s mid-century net-zero target. This study shows that the hubs and clusters approach can facilitate CCS deployment in Spain and other hydrocarbon-limited countries.
Current and Future role of Haber–Bosch Ammonia in a Carbon-free Energy Landscape
Dec 2019
Publication
The future of a carbon-free society relies on the alignment of the intermittent production of renewable energy with our continuous and increasing energy demands. Long-term energy storage in molecules with high energy content and density such as ammonia can act as a buffer versus short-term storage (e.g. batteries). In this paper we demonstrate that the Haber–Bosch ammonia synthesis loop can indeed enable a second ammonia revolution as energy vector by replacing the CO2 intensive methane-fed process with hydrogen produced by water splitting using renewable electricity. These modifications demand a redefinition of the conventional Haber–Bosch process with a new optimisation beyond the current one which was driven by cheap and abundant natural gas and relaxed environmental concerns during the last century. Indeed the switch to electrical energy as fuel and feedstock to replace fossil fuels (e.g. methane) will lead to dramatic energy efficiency improvements through the use of high efficiency electrical motors and complete elimination of direct CO2 emissions. Despite the technical feasibility of the electrically-driven Haber–Bosch ammonia the question still remains whether such revolution will take place. We reveal that its success relies on two factors: increased energy efficiency and the development of small-scale distributed and agile processes that can align to the geographically isolated and intermittent renewable energy sources. The former requires not only higher electrolyser efficiencies for hydrogen production but also a holistic approach to the ammonia synthesis loop with the replacement of the condensation separation step by alternative technologies such as absorption and catalysis development. Such innovations will open the door to moderate pressure systems the development and deployment of novel ammonia synthesis catalysts and even more importantly the opportunity for integration of reaction and separation steps to overcome equilibrium limitations. When realised green ammonia will reshape the current energy landscape by directly replacing fossil fuels in transportation heating electricity etc. and as done in the last century food.
Hydrogenerally - Episode 9: Nuclear Hydrogen
Jan 2023
Publication
In this episode of the podcast Debra Jones Chemistry Knowledge Transfer Manager and Ray Chegwin Nuclear Knowledge Transfer Manager from Innovate UK KTN talk about nuclear uses for hydrogen with special guest Allan Simpson Technical Lead at the National Nuclear Laboratory.
The podcast can be found on their website.
The podcast can be found on their website.
CCS Industrial Clusters: Building a Social License to Operate
Jun 2022
Publication
This paper explores the opportunities for and progress in establishing a social licence to operate (SLO) for CCS in industrial clusters in the UK focusing on the perspectives of key stakeholders. The evolution of narratives and networks relating to geographical clusters as niches for CCS in industrial decarbonisation is evaluated in relation to seven pillars supporting SLO. Evidence is drawn from a combination of cluster mapping documentary analysis and stakeholder interviews to identify the wider contexts underpinning industrial decarbonisation stakeholder networks interaction and communication critical narratives the conditions for establishing trust and confidence different scales of social licence and maintaining a SLO. The delivery of a sustainable industrial decarbonisation strategy will depend on multiple layers of social licence involving discourses at different scales and potentially for different systems (heat transport different industrial processes). Despite setbacks as a result of funding cancellations and changes to government policy the UK is positioned to be at the forefront of CCS deployment. While there is a high ambition and a strong narrative from government of the urgency to accelerate projects involving CCS clear coordinated strategy and funding frameworks are necessary to build confidence that UK policy is both compatible with net zero and economically viable.
Perspectives for a Sustainable Implementation of Super-green Hydrogen Production by Photoelectrochemical Technology in Hard-to-abate Sectors
May 2023
Publication
The energy transition's success hinges on the effectiveness to curbing carbon emissions from hard-to-abate sectors. Hydrogen (H2) has been proposed as the candidate vector that could be used to replace fossils in such energy-intensive industries. Despite green H2 via solar-powered water electrolysis being a reality today the overall defossilization of the hard-to-abate sectors by electrolytic H2 would be unfeasible as it relies on the availability of renewable electricity. In this sense the unbiassed photoelectrochemical water splitting (PEC) as inspired by natural photosynthesis may be a promising alternative expected in the long term. PEC could be partly or even completely decoupled from renewable electricity and then could produce H2 autonomously. However some remaining challenges still limit PEC water splitting to operate sustainably. These limitations need to be evaluated before the scaling up and implementation. A prospective life cycle assessment (LCA) has been used to elucidate a positive performance scenario in which the so-called super-green H2 or photo-H2 could be a sustainable alternative to electro-H2. The study has defined future scenarios by conducting a set of sensitivity assessments determining the figures of operating parameters such as i) the energy to produce the cell; ii) solar-to-hydrogen efficiency (STH); and iii) lifetime. These parameters have been evaluated based on two impact categories: i) Global Warming Potential (GWP); and ii) fossil Abiotic Depletion Potentials (fADP). The mature water electrolysis was used for benchmarking in order to elucidate the target performance in which PEC technology could be positively implemented at large-scale. Efficiencies over 10% (STH) and 7 years of lifetime are compulsory in the coming developments to achieve a positive scaling-up.
Hydrogenerally - Episode 10: Green Hydrogen Production
Feb 2023
Publication
Debra Jones Chemistry Knowledge Transfer Manager and Simon Buckley Zero Emission Mobility Knowledge Transfer Manager from Innovate UK KTN talk about green hydrogen production with their special guest Chris Jackson CEO & Founder at Protium.
This podcast discussion centres around methods of producing clean hydrogen from renewable energy sources the innovative projects Protium is working on and how much green hydrogen will the UK produce by 2030 and beyond.
The podcast can be found on their website.
This podcast discussion centres around methods of producing clean hydrogen from renewable energy sources the innovative projects Protium is working on and how much green hydrogen will the UK produce by 2030 and beyond.
The podcast can be found on their website.
Optimization of High-Temperature Electrolysis System for Hydrogen Production Considering High-Temperature Degradation
Mar 2023
Publication
Solid oxide electrolysis cells (SOECs) have great application prospects because of their excellent performance but the long-term applications of the stacks are restricted by the structural degradation under the high-temperature conditions. Therefore an SOEC degradation model is developed and embedded in a process model of the high-temperature steam electrolysis (HTSE) system to investigate the influence of the stack degradation at the system level. The sensitivity analysis and optimization were carried out to study the influence factors of the stack degradation and system hydrogen production efficiency and search for the optimal operating conditions to improve the hydrogen production efficiency and mitigate the stack degradation. The analysis results show that the high temperature and large current density can accelerate the stack degradation but improve the hydrogen production efficiency while the high temperature gradually becomes unfavorable in the late stage. The low air-to-fuel feed ratio is beneficial to both the degradation rate and hydrogen production efficiency. The results show that the optimization method can improve the hydrogen production efficiency and inhibit the stack degradation effectively. Moreover part of the hydrogen production efficiency has to be sacrificed in order to obtain a lower stack degradation rate.
Recent Insights into Low-Surface-Area Catalysts for Hydrogen Production from Ammonia
Nov 2022
Publication
A potential method of storing and transporting hydrogen safely in a cost-effective and practical way involves the utilization of molecules that contain hydrogen in their structure such as ammonia. Because of its high hydrogen content and carbon-free molecular structure as well as the maturity of related technology (easy liquefaction) ammonia has gained attention as a “hydrogen carrier” for the generation of energy. Unfortunately hydrogen production from ammonia requires an efficient catalyst to achieve high conversion at low reaction temperatures. Recently very attractive results have been obtained with low-surface-area materials. This review paper is focused on summarizing and comparing recent advances in novel economic and active catalysts for this reaction paying particular attention to materials with low surface area such as silicon carbide (SiC) and perovskites (ABO3 structure). The effects of the supports the active phase and the addition of promoters in such low-porosity materials have been analyzed in detail. Advances in adequate catalytic systems (including support and active metal) benefit the perspective of ammonia as a hydrogen carrier for the decarbonization of the energy sector and accelerate the “hydrogen economy”.
Maximizing Green Hydrogen Production from Water Electrocatalysis: Modeling and Optimization
Mar 2023
Publication
The use of green hydrogen as a fuel source for marine applications has the potential to significantly reduce the carbon footprint of the industry. The development of a sustainable and cost-effective method for producing green hydrogen has gained a lot of attention. Water electrolysis is the best and most environmentally friendly method for producing green hydrogen-based renewable energy. Therefore identifying the ideal operating parameters of the water electrolysis process is critical to hydrogen production. Three controlling factors must be appropriately identified to boost hydrogen generation namely electrolysis time (min) electric voltage (V) and catalyst amount (µg). The proposed methodology contains the following two phases: modeling and optimization. Initially a robust model of the water electrolysis process in terms of controlling factors was established using an adaptive neuro-fuzzy inference system (ANFIS) based on the experimental dataset. After that a modern pelican optimization algorithm (POA) was employed to identify the ideal parameters of electrolysis duration electric voltage and catalyst amount to enhance hydrogen production. Compared to the measured datasets and response surface methodology (RSM) the integration of ANFIS and POA improved the generated hydrogen by around 1.3% and 1.7% respectively. Overall this study highlights the potential of ANFIS modeling and optimal parameter identification in optimizing the performance of solar-powered water electrocatalysis systems for green hydrogen production in marine applications. This research could pave the way for the more widespread adoption of this technology in the marine industry which would help to reduce the industry’s carbon footprint and promote sustainability.
Experimental Study of the Feasibility of In‐Situ Hydrogen Generation from Gas Reservoir
Nov 2022
Publication
Due to there is no better way to exploit depleted gas reservoirs and hydrogen can generate from natural gas combustion. In this paper the possibility of in‐situ hydrogen generation in air injected gas reservoirs was determined through pseudo dynamic experiments. The study indicated that highertemperature and steam/methane ratio can generate more hydrogen and the temperature should not be lower than 600 °C within gas reservoirs. The debris has positive catalysis for hydrogen generation. The maximum mole fraction of hydrogen was 26.63% at 600 °C.
Influence of Renewable Energy Power Fluctuations on Water Electrolysis for Green Hydrogen Production
Nov 2022
Publication
The development of renewable energy technologies is essential to achieve carbon neutrality. Hydrogen can be stably stored and transported in large quantities to maximize power utilization. Detailed understanding of the characteristics and operating methods of water electrolysis technologies in which naturally intermittent fluctuating power is used directly is required for green hydrogen production because fluctuating power-driven water electrolysis processes significantly differ from industrial water electrolysis processes driven by steady grid power. Thus it is necessary to overcome several issues related to the direct use of fluctuating power. This article reviews the characteristics of fluctuating power and its generation as well as the current status and issues related to the operation conditions water electrolyzer configuration system requirements stack/catalyst durability and degradation mechanisms under the direct use of fluctuating power sources. It also provides an accelerated degradation test protocol method for fair catalyst performance comparison and share of effective design directions. Finally it discusses potential challenges and recommendations for further improvements in water electrolyzer components and systems suitable for practical use suggesting that a breakthrough could be realized toward the achievement of a sustainable hydrogen-based society.
A Technical, Economic and Environmental Analysis of Combining Geothermal Energy with Carbon Sequestration for Hydrogen Production
Jul 2014
Publication
Among numerous techniques for the hydrogen production without harmful emissions especially avoiding the carbon dioxide emissions hydrogen technologies driven by geothermal energy represent an attractive solution. This paper is interested in the process by which the electricity generated from geothermal power plant that is operated using CO2 as heat transmission fluid is exploited for hydrogen production through water electrolysis. A numerical simulation is used to evaluate the potential for hydrogen production and to estimate the levelized cost of electrolytic hydrogen. We also present brief analysis of environmental issues including the carbon tax. The results show that the process has a good potential for geothermal hydrogen production is capable of producing about 22 kg/h of electrolytic hydrogen for the geothermal source of carbon dioxide mass flow rate of 40 kg/s and a temperature of 296 K. In economic regard the electric energy system costs are the major component of the total hydrogen production cost (more than 90%). The estimated cost of hydrogen is 8.24 $/kg H2. By including the carbon tax the cost of hydrogen production becomes far more competitive.
Feasibility Analysis of Hydrogen Production Potential from Rooftop Solar Power Plant for Industrial Zones in Vietnam
Nov 2022
Publication
Currently global energy transformation and the promotion of renewable energy use are being taken care of to minimize the harm to the environment. However the disadvantage of renewable energy is the random change which leads to the regulation of grid operations which is very difficult when the capacity of renewable energy sources accounts for a large proportion. The hydrogen production technology from wind and solar energy sources is one of the possible methods to minimize adverse impacts on the utility grid and serve the load demand of industrial zones. In this study the photovoltaic (PV) hydrogen production potential for industrial zones in Vietnam is analyzed. The Homer was used to simulate and calculate power output. The results showed that the Hai Duong province has the lowest solar radiation so the solar power output is 3600389 kWh/year and the amount of hydrogen generated is less so it mainly serves the hydrogen load while the fuel cell can only generate very low amounts of electricity of about 4150 kWh/year for direct current (DC) load. The hybrid power systems in the typical industrial plant in Quang Nam province Binh Thuan province Can Tho city can generate about 17386 kg/year to 17422 kg/year to supply the operation of fuel cells based on the value of solar radiation of each province. The better the area with solar potential the lower the net present cost (NPC) cost of energy (COE) and operation cost so the economical and technical efficiency of the PV–Fuel cell hybrid power system will increase.
Operation of Power-to-X-Related Processes Based on Advanced Data-Driven Methods: A Comprehensive Review
Oct 2022
Publication
This study is a systematic analysis of selected research articles about power-to-X (P2X)- related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels which has led to a huge amount of greenhouse gas emissions that are the source of global warming. One of the most supported actions against such a phenomenon is to employ renewable energy resources some of which are intermittent such as solar and wind. This brings the need for large-scale longer-period energy storage solutions. In this sense the P2X process chain could play this role: renewable energy can be converted into storable hydrogen chemicals and fuels via electrolysis and subsequent synthesis with CO2. The main contribution of this study is to provide a systematic articulation of advanced data-driven methods and latest technologies such as the Internet of Things (IoT) big data analytics and machine learning for the efficient operation of P2X-related processes. We summarize our findings into different working architectures and illustrate them with a numerical result that employs a machine learning model using historic data to define operational parameters for a given P2X process.
Recent Advances in Power-to-X Technology for the Production of Fuels and Chemicals
Jun 2019
Publication
Environmental issues related to greenhouse gas emissions are progressively pushing the transition toward fossil-free energy scenario in which renewable energies such as solar and wind power will unavoidably play a key role. However for this transition to succeed significant issues related to renewable energy storage have to be addressed. Power-to-X (PtX) technologies have gained increased attention since they actually convert renewable electricity to chemicals and fuels that can be more easily stored and transported. H2 production through water electrolysis is a promising approach since it leads to the production of a sustainable fuel that can be used directly in hydrogen fuel cells or to reduce carbon dioxide (CO2) in chemicals and fuels compatible with the existing infrastructure for production and transportation. CO2 electrochemical reduction is also an interesting approach allowing the direct conversion of CO2 into value-added products using renewable electricity. In this review attention will be given to technologies for sustainable H2 production focusing on water electrolysis using renewable energy as well as on its remaining challenges for large scale production and integration with other technologies. Furthermore recent advances on PtX technologies for the production of key chemicals (formic acid formaldehyde methanol and methane) and fuels (gasoline diesel and jet fuel) will also be discussed with focus on two main pathways: CO2 hydrogenation and CO2 electrochemical reduction.
Green Hydrogen Production Technologies from Ammonia Cracking
Nov 2022
Publication
The rising technology of green hydrogen supply systems is expected to be on the horizon. Hydrogen is a clean and renewable energy source with the highest energy content by weight among the fuels and contains about six times more energy than ammonia. Meanwhile ammonia is the most popular substance as a green hydrogen carrier because it does not carry carbon and the total hydrogen content of ammonia is higher than other fuels and is thus suitable to convert to hydrogen. There are several pathways for hydrogen production. The considered aspects herein include hydrogen production technologies pathways based on the raw material and energy sources and different scales. Hydrogen can be produced from ammonia through several technologies such as electro-chemical photocatalytic and thermochemical processes that can be used at production plants and fueling stations taking into consideration the conversion efficiency reactors catalysts and their related economics. The commercial process is conducted by using expensive Ru catalysts in the ammonia converting process but is considered to be replaced by other materials such as Ni Co La and other perovskite catalysts which have high commercial potential with equivalent activity for extracting hydrogen from ammonia. For successful engraftment of ammonia to hydrogen technology into industry integration with green technologies and economic methods as well as safety aspects should be carried out.
Design of a Multi-inlet Solar Thermochemical Reactor for Steam Methane Reforming with Improved Performance
Feb 2023
Publication
Reactor structure design plays an important role in the performance of solar-thermal methane reforming reactors. Based on a conventional preheating reactor this study proposed a cylindrical solar methane reforming reactor with multiple inlets to vary the temperature field distribution which improved the temperature of the reaction region in the reactor thereby improving the reactor performance. A multi-physical model that considers mass momentum species and energy conservation as well as thermochemical reaction kinetics of methane reforming was applied to numerically investigate the reactor performance and analyze the factors that affect performance improvement. It was found that compared with a conventional preheating reactor the proposed cylindrical reactor with inner and external inlets for gas feeding enhanced heat recovery from the exhausted gas and provided a more suitable temperature field for the reaction in the reactor. Under different operating conditions the methane conversion in the cylindrical reactor with multi-inlet increased by 9.5% to 19.1% and the hydrogen production was enhanced by 12.1% to 40.3% in comparison with the conventional design even though the total reaction catalyst volume was reduced.
Understanding Degradation Effects of Elevated Temperature Operating Conditions in Polymer Electrolyte Water Electrolyzers
Apr 2021
Publication
The cost of polymer electrolyte water electrolysis (PEWE) is dominated by the price of electricity used to power the water splitting reaction. We present a liquid water fed polymer electrolyte water electrolyzer cell operated at a cell temperature of 100 °C in comparison to a cell operated at state-of-the-art operation temperature of 60 °C over a 300 h constant current period. The hydrogen conversion efficiency increases by up to 5% at elevated temperature and makes green hydrogen cheaper. However temperature is a stress factor that accelerates degradation causes in the cell. The PEWE cell operated at a cell temperature of 100 °C shows a 5 times increased cell voltage loss rate compared to the PEWE cell at 60 °C. The initial performance gain was found to be consumed after a projected operation time of 3500 h. Elevated temperature operation is only viable if a voltage loss rate of less than 5.8 μV h−1 can be attained. The major degradation phenomena that impact performance loss at 100 °C are ohmic (49%) and anode kinetic losses (45%). Damage to components was identified by post-test electron-microscopic analysis of the catalyst coated membrane and measurement of cation content in the drag water. The chemical decomposition of the ionomer increases by a factor of 10 at 100 °C vs 60 °C. Failure by short circuit formation was estimated to be a failure mode after a projected lifetime 3700 h. At elevated temperature and differential pressure operation hydrogen gas cross-over is limiting since a content of 4% hydrogen in oxygen represents the lower explosion limit.
Stoichiometric Equilibrium Model based Assessment of Hydrogen Generation through Biomass Gasification
Sep 2016
Publication
Hydrogen produced from renewable energy sources is clean and sustainable. Biomass gasification has a significant role in the context of hydrogen generation from biomass. Assessment of the performance of biomass gasification process regarding the product gas yield and composition can be performed using mathematical models. Among the different mathematical models thermodynamic equilibrium models are simple and useful tools for the first estimate and preliminary comparison and assessment of gasification process. A stoichiometric thermodynamic equilibrium model is developed here and its performance is validated for steam gasification and air-steam gasification. The model is then used to assess the feasibility of different biomass feedstock for gasification based on hydrogen yield and lower heating value.
Prediction of Transient Hydrogen Flow of Proton Exchange Membrane Electrolyzer Using Artificial Neural Network
Aug 2023
Publication
A proton exchange membrane (PEM) electrolyzer is fed with water and powered by electric power to electrochemically produce hydrogen at low operating temperatures and emits oxygen as a by-product. Due to the complex nature of the performance of PEM electrolyzers the application of an artificial neural network (ANN) is capable of predicting its dynamic characteristics. A handful of studies have examined and explored ANN in the prediction of the transient characteristics of PEM electrolyzers. This research explores the estimation of the transient behavior of a PEM electrolyzer stack under various operational conditions. Input variables in this study include stack current oxygen pressure hydrogen pressure and stack temperature. ANN models using three differing learning algorithms and time delay structures estimated the hydrogen mass flow rate which had transient behavior from 0 to 1 kg/h and forecasted better with a higher count (>5) of hidden layer neurons. A coefficient of determination of 0.84 and a mean squared error of less than 0.005 were recorded. The best-fitting model to predict the dynamic behavior of the hydrogen mass flow rate was an ANN model using the Levenberg–Marquardt algorithm with 40 neurons that had a coefficient of determination of 0.90 and a mean squared error of 0.00337. In conclusion optimally fit models of hydrogen flow from PEM electrolyzers utilizing artificial neural networks were developed. Such models are useful in establishing an agile flow control system for the electrolyzer system to help decrease power consumption and increase efficiency in hydrogen generation.
Massive Green Hydrogen Production Using Solar and Wind Energy: Comparison between Europe and the Middle East
Jul 2023
Publication
This comparative study examines the potential for green hydrogen production in Europe and the Middle East leveraging 3MWp solar and wind power plants. Experimental weather data from 2022 inform the selection of two representative cities namely Krakow Poland (Europe) and Diyala Iraq (Middle East). These cities are chosen as industrial–residential zones representing the respective regions’ characteristics. The research optimizes an alkaline water electrolyzer capacity in juxtaposition with the aforementioned power plants to maximize the green hydrogen output. Economic and environmental factors integral to green hydrogen production are assessed to identify the region offering the most advantageous conditions. The analysis reveals that the Middle East holds superior potential for green hydrogen production compared to Europe attributed to a higher prevalence of solar and wind resources coupled with reduced land and labor costs. Hydrogen production costs in Europe are found to range between USD 9.88 and USD 14.31 per kilogram in contrast to the Middle East where costs span from USD 6.54 to USD 12.66 per kilogram. Consequently the Middle East emerges as a more feasible region for green hydrogen production with the potential to curtail emissions enhance air quality and bolster energy security. The research findings highlight the advantages of the Middle East industrial–residential zone ‘Diyala’ and Europe industrial–residential zone ‘Krakow’ in terms of their potential for green hydrogen production.
Hydrogen as Energy Carrier: Techno-economic Assessment of Decentralized Hydrogen Production in Germany
Jun 2021
Publication
Political and scientific discussions on changing German energy supply mix and challenges of such energy transition are already well established. At the supply level energy storage seems to be the biggest challenge ahead for such transition. Hydrogen could be one of the solutions for future energy transition if it is produced using renewable energy resources. In order to analyze the future role of hydrogen its economic performance analysis is inevitable. This has been done in this research for a case study site in Cologne. The potential of hydrogen production with the use of solar electricity powered electrolyzers (alkaline and proton exchange membrane (PEM)) has been analyzed. Both grid connected and off grid modes of solar hydrogen production are considered. Economic performance results are presented for six scenarios. Hydrogen produced with the grid connected solar photovoltaics system coupled with alkaline electrolyzers was found the cheapest with the levelized cost of hydrogen (LCOH) at 6.23 V/kg. These costs are comparable with the current hydrogen price at commercial refueling station in Cologne. On the other hand the LCOH of off grid systems with both alkaline and PEM electrolyzers is expensive as expected the most expensive LCOH among six scenarios reached to 57.61 V/kg.
CFD Simulation of a Hybrid Solar/Electric Reactor for Hydrogen and Carbon Production from Methane Cracking
Jan 2023
Publication
Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds fog day-night cycle etc.) generally hinder continuity and stability of the solar process. Therefore a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly the influence of various process parameters including temperature gas residence time methane dilution and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance.
Ammonia Decomposition in the Process Chain for a Renewable Hydrogen Supply
Jun 2022
Publication
This review article deals with the challenge to identify catalyst materials from literature studies for the ammonia decomposition reaction with potential for application in large-scale industrial processes. On the one hand the requirements on the catalyst are quite demanding. Of central importance are the conditions for the primary reaction that have to be met by the catalyst. Likewise the catalytic performance i.e. an ideally quantitative conversion and a high lifetime are critical as well as the consideration of requirements on the product properties in terms of pressure or by-products for potential follow-up processes in this case synthesis gas applications. On the other hand the evaluation of the multitude of literature studies poses difficulties due to significant varieties in catalytic testing protocols.
Green Hydrogen from Anion Exchange Membrane Water Electrolysis: A Review of Recent Developments in Critical Materials and Operating Conditions
Mar 2020
Publication
Hydrogen production using water electrolysers equipped with an anion exchange membrane (AEM) a pure water feed and cheap components such as platinum group metal-free catalysts and stainless steel bipolar plates (BPP) can challenge proton exchange membrane (PEM) electrolysis systems as the state of the art. For this to happen the performance of the AEM electrolyzer must match the compact design stability H2 purity and high current densities of PEM systems. Current research aims at bringing AEM water electrolysis technology to an advanced level in terms of electrolysis cell performance. Such technological advances must be accompanied by demonstration of the cost advantages of AEM systems. The current state of the art in AEM water electrolysis is defined by sporadic reports in the academic literature mostly dealing with catalyst or membrane development. The development of this technology requires a future roadmap for systematic development and commercialization of AEM systems and components. This will include basic and applied research technology development & integration and testing at a laboratory scale of small demonstration units (AEM electrolyzer shortstacks) that can be used to validate the technology (from TRL 2–3 currently to TRL 4–5). This review paper gathers together recent important research in critical materials development (catalysts membranes and MEAs) and operating conditions (electrolyte composition cell temperature performance achievements). The aim of this review is to identify the current level of materials development and where improvements are required in order to demonstrate the feasibility of the technology. Once the challenges of materials development are overcome AEM water electrolysis can drive the future use of hydrogen as an energy storage vector on a large scale (GW) especially in developing countries.
Solar Water Splitting by Photovoltaic-electrolysis with a Solar-to-hydrogen Efficiency over 30%
Oct 2016
Publication
Hydrogen production via electrochemical water splitting is a promising approach for storing solar energy. For this technology to be economically competitive it is critical to develop water splitting systems with high solar-to-hydrogen (STH) efficiencies. Here we report a photovoltaic-electrolysis system with the highest STH efficiency for any water splitting technology to date to the best of our knowledge. Our system consists of two polymer electrolyte membrane electrolysers in series with one InGaP/GaAs/GaInNAsSb triple-junction solar cell which produces a large-enough voltage to drive both electrolysers with no additional energy input. The solar concentration is adjusted such that the maximum power point of the photovoltaic is well matched to the operating capacity of the electrolysers to optimize the system efficiency. The system achieves a 48-h average STH efficiency of 30%. These results demonstrate the potential of photovoltaic-electrolysis systems for cost-effective solar energy storage.
Analysis of Hydrogen Production Costs in Steam-Methane Reforming Considering Integration with Electrolysis and CO2 Capture
Aug 2022
Publication
Global hydrogen production is dominated by the Steam-Methane Reforming (SMR) route which is associated with significant CO2 emissions and excess process heat. Two paths to lower specific CO2 emissions in SMR hydrogen production are investigated: (1) the integration of CO2 capture and compression for subsequent sequestration or utilization and (2) the integration of electrolysis for increased hydrogen production. In both cases the excess process heat is utilized to drive the emissions reduction options. Four different design regimes for integration of carbon capture and compression with the SMR process are identified. Techno-economic analyses are performed to study the effect of CO2 mitigation on hydrogen production costs compared to grey hydrogen production without emissions mitigation options. Integration with electrolysis is shown to be less attractive compared to the proposed heat and power integration schemes for the SMR process with CO2 capture and compression for subsequent sequestration or utilization which can reduce emissions by 90% with hydrogen production costs increasing only moderately by 13%. This blue hydrogen production is compared in terms of costs and emissions against the emerging alternative production by electrolysis in the context of renewable and fossil electricity generation and electricity mixes while considering life-cycle emissions.
Hydrogen Production System Using Alkaline Water Electrolysis Adapting to Fast Fluctuating Photovoltaic Power
Apr 2023
Publication
Using photovoltaic (PV) energy to produce hydrogen through water electrolysis is an environmentally friendly approach that results in no contamination making hydrogen a completely clean energy source. Alkaline water electrolysis (AWE) is an excellent method of hydrogen production due to its long service life low cost and high reliability. However the fast fluctuations of photovoltaic power cannot integrate well with alkaline water electrolyzers. As a solution to the issues caused by the fluctuating power a hydrogen production system comprising a photovoltaic array a battery and an alkaline electrolyzer along with an electrical control strategy and energy management strategy is proposed. The energy management strategy takes into account the predicted PV power for the upcoming hour and determines the power flow accordingly. By analyzing the characteristics of PV panels and alkaline water electrolyzers and imposing the proposed strategy this system offers an effective means of producing hydrogen while minimizing energy consumption and reducing damage to the electrolyzer. The proposed strategy has been validated under various scenarios through simulations. In addition the system’s robustness was demonstrated by its ability to perform well despite inaccuracies in the predicted PV power.
Potential Renewable Hydrogen from Curtailed Electricity to Decarbonize ASEAN’s Emissions: Policy Implications
Dec 2020
Publication
The power generation mix of the Association of Southeast Asian Nations (ASEAN) is dominated by fossil fuels which accounted for almost 80% in 2017 and are expected to account for 82% in 2050 if the region does not transition to cleaner energy systems. Solar and wind power are the most abundant energy resources but contribute negligibly to the power mix. Investors in solar or wind farms face high risks from electricity curtailment if surplus electricity is not used. Employing the policy scenario analysis of the energy outlook modelling results this paper examines the potential scalability of renewable hydrogen production from curtailed electricity in scenarios of high share of variable renewable energy in the power generation mix. The study found that ASEAN has high potential in developing renewable hydrogen production from curtailed electricity. The study further found that the falling cost of renewable hydrogen production could be a game changer to upscaling the large-scale hydrogen production in ASEAN through policy support. The results implied a future role of renewable hydrogen in energy transition to decarbonize ASEAN’s emissions.
Low-carbon and Cost-efficient Hydrogen Optimisation through a Grid-connected Electrolyser: The Case of GreenLab Skive
Nov 2022
Publication
Power-to-X technologies are a promising means to achieve Denmark’s carbon emission reduction targets. Water electrolysis can potentially generate carbon-neutral fuels if powered with renewable electricity. However the high variability of renewable sources threatens the Power-to-X plant’s cost-efficiency instead favouring high and constant operation rates. Therefore a diversified electricity supply is often an option to maximise the load factor of the Power-to-X systems. This paper analyses the impact of using different power sources on the cost of production and the carbon intensity of hydrogen produced by a Power-to-X system. GreenLab Skive the world’s first industrial facility with Power-to-X integrated into an industrial symbiosis network has been used as a case study. Results show that the wind/PV/grid-connected electrolyser for hydrogen and electricity production can reduce operational costs and emissions saving 30.6 × 107 kgCO2 and having a Net Present Value twice higher than a grid-connected electrolyser. In addition the carbon emission coefficient for this configuration is 3.5 × 10− 2 kgH2/kgCO2 against 7.0 gH2/gCO2 produced by Steam Methane Reforming. A sensitivity analysis detects the optimal capacity ratio between the renewables and the electrolyser. A plateau is reached for carbon emission performances suggesting a wind/grid-connected electrolyser setup with a wind farm three times the size of the electrolyser. Results demonstrate that hydrogen cost is not competitive yet with the electricity suggesting an investment cost reduction but can be competitive with the current hydrogen price if the wind capacity is less than three times the electrolyser capacity.
Biohydrogen Production from Biomass Sources: Metabolic Pathways and Economic Analysis
Sep 2021
Publication
The commercialization of hydrogen as a fuel faces severe technological economic and environmental challenges. As a method to overcome these challenges microalgal biohydrogen production has become the subject of growing research interest. Microalgal biohydrogen can be produced through different metabolic routes the economic considerations of which are largely missing from recent reviews. Thus this review briefly explains the techniques and economics associated with enhancing microalgae-based biohydrogen production. The cost of producing biohydrogen has been estimated to be between $10 GJ-1 and $20 GJ−1 which is not competitive with gasoline ($0.33 GJ−1 ). Even though direct biophotolysis has a sunlight conversion efficiency of over 80% its productivity is sensitive to oxygen and sunlight availability. While the electrochemical processes produce the highest biohydrogen (>90%) fermentation and photobiological processes are more environmentally sustainable. Studies have revealed that the cost of producing biohydrogen is quite high ranging between $2.13 kg−1 and 7.24 kg−1 via direct biophotolysis $1.42kg−1 through indirect biophotolysis and between $7.54 kg−1 and 7.61 kg−1 via fermentation. Therefore low-cost hydrogen production technologies need to be developed to ensure long-term sustainability which requires the optimization of critical experimental parameters microalgal metabolic engineering and genetic modification.
Green Hydrogen Production from Raw Biogas: A Techno-Economic Investigation of Conventional Processes Using Pressure Swing Adsorption Unit
Feb 2018
Publication
This paper discusses the techno-economic assessment of hydrogen production from biogas with conventional systems. The work is part of the European project BIONICO whose purpose is to develop and test a membrane reactor (MR) for hydrogen production from biogas. Within the BIONICO project steam reforming (SR) and autothermal reforming (ATR) have been identified as well-known technologies for hydrogen production from biogas. Two biogases were examined: one produced by landfill and the other one by anaerobic digester. The purification unit required in the conventional plants has been studied and modeled in detail using Aspen Adsorption. A pressure swing adsorption system (PSA) with two and four beds and a vacuum PSA (VPSA) made of four beds are compared. VPSA operates at sub-atmospheric pressure thus increasing the recovery: results of the simulations show that the performances strongly depend on the design choices and on the gas feeding the purification unit. The best purity and recovery values were obtained with the VPSA system which achieves a recovery between 50% and 60% at a vacuum pressure of 0.1 bar and a hydrogen purity of 99.999%. The SR and ATR plants were designed in Aspen Plus integrating the studied VPSA model and analyzing the behavior of the systems at the variation of the pressure and the type of input biogas. The SR system achieves a maximum efficiency calculated on the LHV of 52% at 12 bar while the ATR of 28% at 18 bar. The economic analysis determined a hydrogen production cost of around 5 €/kg of hydrogen for the SR case.
Review and Harmonization of the Life-Cycle Global Warming Impact of PV-Powered Hydrogen Production by Electrolysis
Sep 2021
Publication
This work presents a review of life-cycle assessment (LCA) studies of hydrogen electrolysis using power from photovoltaic (PV) systems. The paper discusses the assumptions strengths and weaknesses of 13 LCA studies and identifies the causes of the environmental impact. Differences in assumptions of system boundaries system sizes evaluation methods and functional units make it challenging to directly compare the Global Warming Potential (GWP) resulting from different studies. To simplify this process 13 selected LCA studies on PV-powered hydrogen production have been harmonized following a consistent framework described by this paper. The harmonized GWP values vary from 0.7 to 6.6 kg CO2-eq/kg H2 which can be considered a wide range. The maximum absolute difference between the original and harmonized GWP results of a study is 1.5 kg CO2-eq/kg H2. Yet even the highest GWP of this study is over four times lower than the GWP of grid-powered electrolysis in Germany. Due to the lack of transparency of most LCAs included in this review full identification of the sources of discrepancies (methods applied assumed production conditions) is not possible. Overall it can be concluded that the environmental impact of the electrolytic hydrogen production process is mainly caused by the GWP of the electricity supply. For future environmental impact studies on hydrogen production systems it is highly recommended to 1) divide the whole system into well-defined subsystems using compression as the final stage of the LCA and 2) to provide energy inputs/GWP results for the different subsystems.
Alternative and Innovative Solid Oxide Electrolysis Cell Materials: A Short Review
Jun 2021
Publication
Solid oxide electrolysis cell is the leading technology for production of green hydrogen by high temperature electrolysis. However optimization of existing reference materials constituting the cell and development of innovative materials remain critical for solid oxide electrolysis cell. In particular they are key to reach performance and durability targets compatible with a commercialization for the three main markets identified as follows: large-scale H2 production Power-to-X and Power-to-Power. This short review summarizes the latest progress in research and development of alternative and innovative materials for solid oxide electrolysis cells with a main focus on cathode-supported cell materials. A brief description of the layers constituting the solid oxide electrolysis cell is provided with the associated current state-of-the-art materials. A further emphasis on the most promising alternative and innovative materials for each layer follows based on the major aspects from an industrial perspective to reach a competitive hydrogen production cost for the main targeted markets: performance durability scaling up/manufacturing ability and operational flexibility.
Experimental Study for Thermal Methane Cracking Reaction to Generate Very Pur Hydrogen in Small or Medium Scales by Using Regenrative Reactor
Sep 2022
Publication
Non-catalytic thermal methane cracking (TMC) is an alternative for hydrogen manufacturing and traditional commercial processes in small-scale hydrogen generation. Supplying the high-level temperatures (850–1800°C) inside the reactors and reactor blockages are two fundamental challenges for developing this technology on an industrial scale (Mahdi Yousefi and Donne 2021). A regenerative reactor could be a part of a solution to overcome these obstacles. This study conducted an experimental study in a regenerative reactor environment between 850 and 1170°C to collect the conversion data and investigate the reactor efficiency for TMC processes. The results revealed that the storage medium was a bed for carbon deposition and successfully supplied the reaction’s heat with more than 99.7% hydrogen yield (at more than 1150°C). Results also indicated that the reaction rate at the beginning of the reactor is much higher and the temperature dependence in the early stages of the reaction is considerably higher. However after reaching a particular concentration of Hydrogen at each temperature the influence of temperature on the reaction rate decreases and is almost constant. The type of produced carbon in the storage medium and its auto-catalytic effect on the reactions were also investigated. Results showed that carbon black had been mostly formed but in different sizes from 100 to 2000 nm. Increasing the reactor temperature decreased the size of the generated carbon. Pre-produced carbon in the reactor did not affect the production rate and is almost negligible at more than 850°C.
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